黄河流域特色保护类村庄种群分布动态与生境选择

基于种群生态学理论,将黄河流域971个国家级特色保护类村庄视作一个地理种群。综合GIS空间分析和数理统计方法,明晰这一种群的分布动态和生境选择特征,进而应用地理探测器对比揭示影响该种群分布的生态因子。结果表明:(1)黄河流域特色保护类村庄的分布密度随种群增长而大幅提高,分布模式随尺度变大由显著聚集转为不显著离散,分布格局随时间推移由多中心向单中心演化,但集聚中心一直位于河谷盆地;(2)黄河流域特色保护类村庄具有“聚中低山区、向阳坡斜坡、喜温暖湿润、近黄河干流”的偏好,趋向中等人口密度、经济欠发达地区分布,主要位于国道沿线30 km、省道沿线10 km、中心城市周边20~80 km、历史城镇周边60 km、旅游景区和文保单位周边20 km范围内;(3)影响特色保护类村庄种群分布的生态因子具有综合性、非等价性和限定性,在黄河流域以文保单位和海拔为主导。

全域土地综合整治视域下的乡村空间重构路径——以汉中市谢村镇26个村庄为例

全域土地综合整治是推进乡村空间重构、建设和美乡村的重要手段。为破解乡村资源利用与要素整合方面的短板,实现乡村全域全要素协调发展。在明晰全域土地综合整治与乡村空间重构逻辑关联的基础上,以具备典型特征的汉中市谢村镇26个村庄为例,基于“人-地-产”耦合互动的分析框架,构建了乡村空间重构评价模型。运用GIS空间分析等技术,定量测度乡村空间重构耦合度与协调度的时空演变规律,并通过诊断模型等方法揭示了影响乡村发展的主要障碍因子。进一步将重构指数与协调度相结合,划分全域土地综合整治的分区格局,并提出相应的整治模式。根据弱势系统识别结果,提出了差异化的乡村空间重构路径:以盘活低效用地为核心,重构全域空间;以开展环境整治为途径,塑造宜居空间;以保护历史文化为抓手,保障宜业空间。

东南沿海传统村落人口外流格局及驱动机制的微观研究

该文以浙闽粤三省959个国家级传统村落为样本,综合运用加权核密度估计、克里金插值等方法,在村级尺度多维刻画东南沿海传统村落人口外流的空间格局,利用相关系数和地理探测器定量探测影响因子的作用,进而从地理资本视角分析影响因子的作用机理并构建驱动机制。结果表明:①东南沿海传统村落人口外流的地形分异和山区集聚格局显著,重心位于闽北山区,核心源区位于浙西南山区;②地形条件、人地关系、城村联系和经济收入是影响人口外流率村际差异的显著因子,人均耕地面积与其他因子的协同作用是主导驱动力;③传统村落人口外流是海拔、坡度、地形起伏度等7个显著因子协同作用的结果,是生态资本、区位资本和经济资本的函数。

Reliability analysis of slope stability by neural network,principal component analysis,and transfer learning techniques

The prediction of slope stability is considered as one of the critical concerns in geotechnical engineering.Conventional stochastic analysis with spatially variable slopes is time-consuming and highly computation-demanding.To assess the slope stability problems with a more desirable computational effort,many machine learning(ML)algorithms have been proposed.However,most ML-based techniques require that the training data must be in the same feature space and have the same distribution,and the model may need to be rebuilt when the spatial distribution changes.This paper presents a new ML-based algorithm,which combines the principal component analysis(PCA)-based neural network(NN)and transfer learning(TL)techniques(i.e.PCAeNNeTL)to conduct the stability analysis of slopes with different spatial distributions.The Monte Carlo coupled with finite element simulation is first conducted for data acquisition considering the spatial variability of cohesive strength or friction angle of soils from eight slopes with the same geometry.The PCA method is incorporated into the neural network algorithm(i.e.PCA-NN)to increase the computational efficiency by reducing the input variables.It is found that the PCA-NN algorithm performs well in improving the prediction of slope stability for a given slope in terms of the computational accuracy and computational effort when compared with the other two algorithms(i.e.NN and decision trees,DT).Furthermore,the PCAeNNeTL algorithm shows great potential in assessing the stability of slope even with fewer training data.

热屏结构对300 mm半导体级单晶硅生长过程温度分布影响的数值模拟

半导体级单晶硅是芯片的基础核心材料,不仅要求控制杂质浓度,还对晶体的缺陷有很高的要求。原生点缺陷浓度作为衡量晶体品质的重要指标之一,需要通过热场的优化、晶体生长温度场的调整、晶体生长过程中晶棒温度分布的控制,以及V/G值(拉速与晶棒内轴向温度梯度比值)的优化来调控。本文采用ANSYS软件中流体计算模块Fluent的有限体积分析法,研究了不同热屏结构对300 mm半导体级直拉单晶硅温度分布的影响。针对二段式热屏,模拟了不同热屏角度下拉晶初期(400 mm)、中期(800和1400 mm)和末期(2000 mm)三个等径阶段的温度分布、固液界面轴向温度梯度和V/G值。通过分析各阶段V/G值的变化,在相对较大的温度梯度下,寻找到了一种V/G值更接近临界值ζ且径向均一性更优的热屏结构,为控制缺陷的浓度提供更好的条件。通过对晶棒热历史的讨论,优化热屏结构以缩短降温周期,为控制缺陷的尺寸提供更好的条件。模拟计算结果表明,热屏夹角为110°、热屏下段厚度为70 mm、热屏内壁与晶棒间距为30 mm时,其结构设计能够提供低缺陷单晶硅生产的温度分布条件。

基于时频感知双路径Conformer的语音增强

近年来,Conformer在语音领域的应用表现较为突出。该模块通过结合多头自注意力机制和卷积神经网络,能够同时关注短时和长时序列信息,从而在语音处理任务中表现出卓越的性能。在此基础上提出了一种基于时频感知双路径Conformer的语音增强网络(TFDPCNet)。首先,该网络将改进的Conformer结构作为核心,采用双路径结构,构成时频感知的双路径Conformer模块(TFDP-Conformer),增强了整体网络的时频提取能力;同时,为了减小时频特征融合的难度,提出了注意力门控交叉融合模块(AGCF),通过额外的注意力门进一步增强了网络训练过程中时频特征的交互,提高了时频特征的利用率;最后,引用度量鉴别器,并对其进行适当剪枝,使得增强后的音频和原始音频在量化评价指标上保持更高的一致性。实验结果表明,相比于TSTNN算法,TFDPCNet在主观和客观指标上都有明显提高。

Progress on immuno-microenvironment and immune-related therapies in patients with pseudomyxoma peritonei

Pseudomyxoma peritonei(PMP) is an indolent malignant syndrome. The standard treatment for PMP is cytoreductive surgery combined with intraperitoneal hyperthermic chemotherapy(CRS + HIPEC). However, the high recurrence rate and latent clinical symptoms and signs are major obstacles to further improving clinical outcomes. Moreover, patients in advanced stages receive little benefit from CRS + HIPEC due to widespread intraperitoneal metastases. Another challenge in PMP treatment involves the progressive sclerosis of PMP cell-secreted mucus, which is often increased due to activating mutations in the gene coding for guanine nucleotide-binding protein alpha subunit(GNAS). Consequently, the development of other PMP therapies is urgently needed. Several immune-related therapies have shown promise, including the use of bacterium-derived non-specific immunogenic agents, radioimmunotherapeutic agents, and tumor cell-derived neoantigens, but a well-recognized immunotherapy has not been established. In this review the roles of GNAS mutations in the promotion of mucin secretion and disease development are discussed. In addition, the immunologic features of the PMP microenvironment and immune-associated treatments are discussed to summarize the current understanding of key features of the disease and to facilitate the development of immunotherapies.

Molecular mechanism of flowering time regulation in Brassica rapa:similarities and differences with Arabidopsis

Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable conditions.Brassica rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil crops.Flowering time is one of the most important agricultural traits of B.rapa crops because of its influence on yield and quality.The transition to flowering in B.rapa is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)signaling.These signals are integrated to control the expression of floral integrators BrFTs and BrSOC1s to regulate flowering.In this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in B.rapa and compare this to what is known in Arabidopsis.

Different people,different wild:Comparing and mapping wilderness representation in Wuyishan National Park,China

It is essential to better integrate wilderness representations of different stakeholders into wilderness conservation.The way in which local residents and other stakeholders frame the construction of wilderness of protected areas in developing countries are poorly understood.In these areas,land use policy and decision may lead to conflicts.This study aims to explore existing public wilderness representations using a questionnaire survey(n=514)administered amongst tourists and other stakeholders in the Wuyishan National Park,in southeast China.The spatial differences in public representations of wilderness across different stakeholder groups were compared against expert knowledge.We found that integrated wilderness representation maps of different stakeholder groups were consistent,namely'area where wild animals live','area with no human influence','a barren and lonely area'.However,three sub-representations of the individual stakeholders varied significantly.Moreover,expert-based wilderness mapping did not reflect public representations accurately,and an integrated wilder-ness quality map considering wilderness representations across both stakeholders and experts can better identify detailed wilderness areas.Our study provides new insights and technical support for future exploration of wilder-ness conservation and mapping in China and other countries with insufficient awareness of wilderness values and investigations in a regional scale.

Percutaneous ultrasound-guided coaxial core needle biopsy for the diagnosis of multiple splenic lesions: A case report

BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.

Lateral circumflex femoral artery perforator flap for the reconstruction of head soft tissue defects:Cross-region venous anastomosis

Background:Owing to its unique characteristics,the lateral circumflex femoral artery perforator(LCFAP)flap is often preferred for repairing head wounds with exposed skulls.However,given the vascular distribution in the head,particularly the veins,can lead to postoperative complications such as venous congestion of the flap.The rates of vascular exploration and necrosis in these flaps are significantly higher than in other body regions.Therefore,it is crucial to identify a safe and effective method for venous anastomosis of free flaps in the head region.Methods:This retrospective case series study included 10 patients with large head soft tissue defects treated at the Burn and Plastic Surgery Department of the Affiliated Hospital of Zunyi Medical University from January 2020 to December 2022.The head defects were reconstructed using LCFAP flaps,with flap veins anastomosed to the external jugular vein in the neck,either directly or via a bridging technique.Results:Among the 10 adult patients with massive head wound defects,7(70%)were men.The patients’mean age was 53.0 years(48–59 years).The wound defects were caused by trauma in 6(60%)patients and by tumors in 4(40%)patients.Postoperatively,no significant complications occurred,and all LCFAP flap survived without necrosis.Conclusion:The descending branch of the LCFAP flap effectively repairs massive head wound defects.The venous anastomosis method for this flap is associated with a low incidence of venous complications and a high patency rate,making it a clinically valuable reference.

Runoff Characteristics of Different Stands in Dongjiang Lake Reservoir Area

Different forest stands in the Dongjiang Lake Reservoir area of Zixing were selected as the research objects to study the characteristics of runoff generation in different forest stands.The results showed that there was no significant difference in annual runoff among M3,M1,and M5,and no significant difference between each forest stand and the control.The order was M3(22.75 mm)>M1(21.77 mm)>M5(20.14 mm).Forest vegetation generates less runoff through vegetation restoration compared to the control,indicating that forest vegetation reconstruction and restoration are beneficial for soil and water conservation.

Spatial Heterogeneity of Agricultural Science and Technology Parks Technology Diffusion: A Case Study of Yangling ASTP

Agricultural science and technology parks(ASTPs) represent an important growth pole in China’s agricultural modernization.Clarifying their diffusion laws can optimize the technological diffusion process and improve its efficiency. Our study uses disaggregated spatial information in its model to analyze ASTP technology diffusion in a heterogeneous space. We constructed a comprehensive index system to evaluate the diffusion environmental quality and introduced the heterogeneous diffusion equation to calculate the technological diffusion probability. We applied this framework to a real-world scenario: the apple planting technology diffusion of the Yangling ASTP in the Loess Plateau, China. The results indicated: (1)the technological diffusion environment of the Loess Plateau advantageous apple producing area showed strong spatial heterogeneity caused by climate, topography, and external transportation links.(2) Under the combined effects of distance and spatial heterogeneity, the spatial diffusion pattern of the Yangling ASTP apple technology was expansion diffusion supplemented by hierarchical diffusion and banded diffusion, and (3) ASTP technology diffusion showed a strong distance attenuation effect, and the frictional effect of distance can be decreased by improving the diffusion environmental quality. These laws can promote regional balanced ASTP-driven development.

热屏结构对200 mm半导体级提拉单晶硅中氧含量分布的影响

半导体级单晶硅是芯片的基础核心材料,其晶体的氧含量分布对晶圆品质有重要影响。通过优化提拉单晶炉的热屏结构可有效控制晶体生长过程中的氧含量分布,但难以通过实验探究其内在影响机制。本文采用ANSYS有限元分析,研究了热屏结构对200 mm半导体级直拉单晶硅氧含量分布的影响。针对一段式、二段式两种典型的商用单晶炉热屏结构,模拟了拉晶初期(300 mm)、中期(800 mm)、末期(1000 mm)三个等径阶段的温度场、流场分布,固液界面温度梯度及径向氧含量分布。计算结果表明,与二段式热屏相比,一段式热屏的熔体温度场均一性较好,固液界面的温度梯度较小。此外,一段式热屏的氩气流场有利于熔体自由表面上方SiO气体挥发和减弱熔体的剪切对流,使固液界面前端向晶体扩散的氧减少。因此,一段式热屏的固液界面径向氧含量分布均匀性较好且晶体中的氧含量较低。

Mutagenesis of SlNAC4 by CRISPR/Cas9 alters gene expression and softening of ripening tomato fruit

Softening is one of the key fruit quality traits,which results from the selective expression of cell wall metabolism genes during ripening.The identification of transcription factors(TFs)that regulate fruit softening is an important field in order to understand and control fruit softening.In tomato,NAC(NAM,ATAF,and CUC)TFs members have been demonstrated to be involved in fruit ripening regulation,including NAC-NOR(nonripening),NOR-like1,SlNAC4,SlNAC1.Here,we generated slnac4 mutant knockout(CR-SlNAC4)tomato plant by a clustered regularly interspaced short palindromic repeats genomic targeting system(CRISPR/Cas9)and SlNAC4 overexpressing(OE-SlNAC4)plant.In addition to confirming the previously reported results that SlNAC4 positively regulates fruit ripening,we found that SlNAC4 has a strong effect on tomato fruit softening.Compared with the control fruit,fruit softening was inhibited in slnac4 fruit and conversely was accelerated in OE-SlNAC4 tomato fruit.Through RNA-sequencing(RNA-seq)analysis,we found that expression levels of SlEXP1(expansin)and SlCEL2(endo-β-1,4 glucanase)genes involved in cell wall metabolism were significantly different in WT(wild type)/slnac4 and WT/OE-SlNAC4 fruit.Further study showed that these genes contained a NAC TF binding domain in their promoter regions.In vitro electrophoretic mobility shift assays(EMSA)and dual-luciferase reporter assays(DLR)demonstrated that these two genes were the direct targets of SlNAC4 binding and transactivation.The results enriched the function of SlNAC4 and provided a new dimension in understanding the regulation of tomato fruit softening.

横向磁场下坩埚转速对半导体级直拉单晶硅熔体中流场与氧浓度的影响机制

利用ANSYS有限元软件分析了横向磁场下不同坩埚转速对200 mm半导体级直拉单晶硅的流场及氧浓度的影响。研究结果表明:在横向磁场下,硅熔体的流场和氧浓度分布呈三维非对称性,熔体对流形式主要包括泰勒-普劳德曼漩涡、浮力-热毛细漩涡及次漩涡,其中前两者有助于氧挥发,而次漩涡则起到抑制作用。当坩埚转速较低(0.5~1.0 r/min)时,较弱的熔体对流强度导致坩埚壁与固液界面间的热传导效率低,氧主要以扩散机制迁移至固液界面,熔硅中氧浓度高;当坩埚转速较高(2~2.5 r/min)时,氧通过强对流形式迁移至固液界面。随着坩埚转速增加,次漩涡和浮力-热毛细漩涡的作用强度提高,浮力-热毛细漩涡影响区域远离自由表面,使硅熔体中的氧浓度呈先下降后上升的趋势。数值模拟结果与实验结果均表明,在横向磁场条件下优选1.5 r/min的坩埚转速可获得平均氧浓度较低的单晶硅。上述分析结果可以为横向磁场下半导体级单晶硅拉晶参数优化提供参考依据。

含萘酰亚胺和烷基疏水基的新型表面活性剂合成及性能

为获得高效多功能表面活性剂,设计并合成了一系列萘酰亚胺和长链烷基为疏水基的新型季铵盐阳离子表面活性剂(C_(n)NDA,n=10,12,14,16代表长链烷基链长),并利用红外光谱(FT-IR)、核磁氢谱(^(1)H NMR)、核磁碳谱(^(13)C NMR)和质谱(HRMS)对其结构进行了表征。研究了C_(n)NDA的表面活性、胶束性质、泡沫及抗菌性能。结果表明,C_(n)NDA具有优异的表面活性和泡沫性能。当疏水烷基链长碳数从10增加到16,其cmc值从1.01降至0.026 mmol/L;0.10 g/L的C14NDA水溶液的泡沫半衰期可达16 h。同时C_(n)NDA具有良好的抗菌活性,C_(16)NDA对大肠杆菌和金黄色葡萄球菌的最低杀菌质量浓度分别为3.0和1.2μg/mL。另外,^(1)H NMR和荧光光谱研究表明,C_(n)NDA能够形成分子间氢键,且萘酰亚胺基团间形成了π-π堆积。C_(n)NDA的优异性能与上述分子间的相互作用密切相关。该类表面活性剂在杀菌和泡沫等领域具有潜在的应用前景。

直拉单晶硅中的缺陷形成机理及控制方法

半导体级单晶硅作为半导体产业链中的重要原材料,其杂质、缺陷等品质对电子器件和集成电路的性能起着至关重要的作用。单晶硅生长和加工过程都不可避免地会形成各种缺陷。鉴于直拉法是目前主流的单晶硅制造方法,针对直拉法半导体级单晶硅制造技术中的晶体缺陷工程问题进行了探讨。简要介绍了半导体级单晶硅中各种晶体缺陷以及它们的形成机理。最后,总结了控制缺陷形成的主要方法。

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells(CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

The study of a neutron spectrum unfolding method based on particle swarm optimization combined with maximum likelihood expectation maximization

The neutron spectrum unfolding by Bonner sphere spectrometer(BSS) is considered a complex multidimensional model,which requires complex mathematical methods to solve the first kind of Fredholm integral equation. In order to solve the problem of the maximum likelihood expectation maximization(MLEM) algorithm which is easy to suffer the pitfalls of local optima and the particle swarm optimization(PSO) algorithm which is easy to get unreasonable flight direction and step length of particles, which leads to the invalid iteration and affect efficiency and accuracy, an improved PSO-MLEM algorithm, combined of PSO and MLEM algorithm, is proposed for neutron spectrum unfolding. The dynamic acceleration factor is used to balance the ability of global and local search, and improves the convergence speed and accuracy of the algorithm. Firstly, the Monte Carlo method was used to simulated the BSS to obtain the response function and count rates of BSS. In the simulation of count rate, four reference spectra from the IAEA Technical Report Series No. 403 were used as input parameters of the Monte Carlo method. The PSO-MLEM algorithm was used to unfold the neutron spectrum of the simulated data and was verified by the difference of the unfolded spectrum to the reference spectrum. Finally, the 252Cf neutron source was measured by BSS, and the PSO-MLEM algorithm was used to unfold the experimental neutron spectrum.Compared with maximum entropy deconvolution(MAXED), PSO and MLEM algorithm, the PSO-MLEM algorithm has fewer parameters and automatically adjusts the dynamic acceleration factor to solve the problem of local optima. The convergence speed of the PSO-MLEM algorithm is 1.4 times and 3.1 times that of the MLEM and PSO algorithms. Compared with PSO, MLEM and MAXED, the correlation coefficients of PSO-MLEM algorithm are increased by 33.1%, 33.5% and 1.9%, and the relative mean errors are decreased by 98.2%, 97.8% and 67.4%.