406 research outputs found

    mTOR signaling in skeletal development and disease

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    Cohomology vanishing theorems for free boundary submanifolds

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    In this paper, via a new Hardy type inequality, we establish some cohomology vanishing theorems for free boundary compact submanifolds MnM^n with nā‰„2n\geq2 immersed in the Euclidean unit ball Bn+k\mathbb{B}^{n+k} under one of the pinching conditions āˆ£Ī¦āˆ£2ā‰¤C|\Phi|^2\leq C, āˆ£Aāˆ£2ā‰¤C~|A|^2\leq \widetilde{C}, or āˆ£Ī¦āˆ£ā‰¤R(p,āˆ£Hāˆ£)|\Phi|\leq R(p,|H|), where AA (Ī¦)(\Phi) is the (traceless) second fundamental form, HH is the mean curvature, C,C~C,\widetilde{C} are positive constants and R(p,āˆ£Hāˆ£)R(p,|H|) is a positive function. In particular, we remove the condition on the flatness of the normal bundle, solving the first question, and partially answer the second question on optimal pinching constants proposed by Cavalcante, Mendes and Vit\'{o}rio.Comment: 14 pages, any comments are welcom

    Temporal and Spatial Evolution of Agricultural Carbon Emissions and Their Impact on Functional Zoning: Evidence from Hubei Province

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    Introduction: To investigate the spatiotemporal evolution of agricultural carbon emissions and carbon absorption, analyse the spatiotemporal variations in the carbon balance, delineate carbon-offsetting regions, and formulate low-carbon development strategies tailored to various major functional zones, this study aims to promote coordinated regional ecological and environmental governance. Methods: This study takes a perspective based on major functional zones, focuses on 17 cities in Hubei Province, studies the spatiotemporal variations in agricultural carbon budgets and carbon offsets in each city from the perspective of functional zoning and proposes a spatial optimization scheme for reducing carbon emissions. Results and discussion: The results show that both agricultural carbon emissions and carbon absorption in Hubei Province gradually increased, although the agricultural carbon budgets varied significantly among cities. Arable lands were the main agricultural carbon sinks in Hubei Province. Overall, carbon emissions exhibited declining coreā€“periphery zonation, with Xiangyang, Jingzhou, and Huanggang serving as the centre (high emissions) and the cities of Shennongjia, Enshi, and Yichang serving as the periphery (low emissions). Carbon absorption displayed a U-shaped distribution, with high values in the east, south, and west and low values in the centre and north. The cities of Yichang, Jingmen, and Huanggang were the peak carbon sink areas. In recent years, the coordination between the agricultural carbon emissions and carbon budgets in Hubei Province has gradually improved, and agricultural carbon absorption and emissions have become increasingly balanced. Seven carbon-positive, five carbon-neutral, and five carbon-negative areas were identified in the province. Based on these findings, differentiated carbon emission reduction strategies were proposed to promote coordinated and low-carbon agriculture

    Analysing the Global and Local Spatial Associations of Medical Resources Across Wuhan City Using POI Data

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    Background: There is a sharp contradiction between the supply and demand of medical resources in the provincial capitals of China. Understanding the spatial patterns of medical resources and identifying their spatial association and heterogeneity is a prerequisite to ensuring that limited resources are allocated fairly and optimally, which, along with improvements to urban residentsā€™ quality of life, is a key aim of healthy city planning. However, the existing studies on medical resources pattern mainly focus on their spatial distribution and evolution characteristics, and lack the analyses of the spatial co-location between medical resources from the global and local perspectives. It is worth noting that the research on the spatial relationship between medical resources is an important way to realize the spatial equity and operation efficiency of urban medical resources. Methods: Localized colocation quotient (LCLQ) analysis has been used successfully to measure directional spatial associations and heterogeneity between categorical point data. Using point of interest (POI) data and the LCLQ method, this paper presents the first analysis of spatial patterns and directional spatial associations between six medical resources across Wuhan city. Results: (1) Pharmacies, clinics and community hospitals show ā€œmulticentreā€‰+ā€‰multicircleā€, ā€œcentreā€‰+ā€‰axisā€‰+ā€‰dotā€ and ā€œbandedā€ distribution characteristics, respectively, but specialized hospitals and general hospitals present ā€œsingle coreā€ and ā€œdouble coreā€ modes. (2) Overall, medical resources show agglomeration characteristics. The degrees of spatial agglomeration of the five medical resources, are ranked from high to low as follows: pharmacy, clinic, community hospital, special hospital, general hospital and 3A hospital. (3) Although pharmacies, clinics, and community hospitals of basic medical resources are interdependent, specialized hospitals, general hospitals and 3A hospitals of professional medical resources are also interdependent; furthermore, basic medical resources and professional medical resources are mutually exclusive. Conclusions: Government and urban planners should pay great attention to the spatial distribution characteristics and association intensity of medical resources when formulating relevant policies. The findings of this study contribute to health equity and health policy discussions around basic medical services and professional medical services

    Numerical study on landslide dynamic process and its impact damage prediction to brick-concrete buildings, a case from Fenghuang street landslide in Shaanxi, China

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    The study of landslide dynamic process and impact damage has important theoretical and practical significance for landslide risk quantitative assessment. Taking Fenghuang Street landslide in Ningqiang County, Shaanxi Province, China as an example, the dynamic process of landslide and its damage to brick-concrete structure buildings are predicted by using discrete element method. Firstly, a three-dimensional numerical landslide model is established by means of the particle flow code system (PFC3D), which is based on landslide investigation, surveying, engineering exploration and geotechnical testing. Secondly, the whole process of landslide deformation, failure, movement and impact damage was simulated, and the velocity, displacement and impact force of the landslide in the motion process were quantitatively studied. Thirdly, the building model (brick-concrete structure) located at the foot of the landslide was constructed by PFC3D and finite element software (Midas/gen), respectively. The characteristics of deformation and displacement of the buildings after the landslide impact are analyzed, and the impact damage of the landslide is predicted. The results show that the rear edge of Fenghuang Street landslide first deforms and fails, and the leading edge is gradually pushed out. After the locking section of the front edge is broken, the landslide begins to slide as a whole, which is a typical push landslide. The main sliding time of the landslide is about 30Ā s, the maximum average velocity is 3.2Ā m/s, and the maximum displacement is about 40Ā m. After the landslide hits the building, the building is displaced in the moving direction of the landslide, and the wall of the building impacted by the landslide is destroyed, resulting in an collapse evident. The relevant research methodologies and findings in this paper can provide a reference for the risk assessment of the same type of landslides, especially the quantitative assessment of the vulnerability for the brick-concrete buildings at risk

    Continuous Acetoneā€“Butanolā€“Ethanol (ABE) Fermentation with in Situ Solvent Recovery by Silicalite-1 Filled PDMS/PAN Composite Membrane

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    The pervaporation (PV) performance of a thin-film silicalite-1 filled PDMS/PAN composite membrane was investigated in the continuous acetoneā€“butanolā€“ethanol (ABE) production by a fermentationā€“PV coupled process. Results showed that continuous removal of ABE from the broth at three different dilution rates greatly increased both the solvent productivity and the glucose utilization rate, in comparison to the control batch fermentation. The high solvent productivity reduced the acid accumulation in the broths because most acids were reassimilated by cells for ABE production. Therefore, a higher total solvent yield of 0.37 g/g was obtained in the fermentationā€“PV coupled process, with a highly concentrated condensate containing 89.11ā€“160.00 g/L ABE. During 268 h of the fermentationā€“PV coupled process, the PV membrane showed a high ABE separation factor of more than 30 and a total flux of 486ā€“710 g/m2h. Membrane fouling was negligible for the three different dilution rates. The solution-diffusion model, especially the mass transfer equation, was proved to be applicable to this coupled process.<br/

    Transfer of Bone-Marrow-Derived Mesenchymal Stem Cells Influences Vascular Remodeling and Calcification after Balloon Injury in Hyperlipidemic Rats

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    Bone-marrow-derived mesenchymal stem cells (BM-MSCs) were found to markedly increase atherosclerotic lesion size. The aim of this paper was to investigate whether BM-MSCs contribute to vascular remodeling and calcification after balloon injury in hyperlipidemic rats. Labeled BM-MSCs were found in the lesion of hyperlipidemic rats after balloon injury. Comparing injury group, transferred BM-MSCs significantly triggered vascular negative remodeling, characterized by the changes of remodeling index (0.628 Ā± 0.0293 versus 0.544 Ā± 0.0217), neointimal area (0.078 Ā± 0.015ā€‰mm2 versus 0.098 Ā± 0.019ā€‰mm2), PCNA index (23.91 Ā± 6.59% versus 43.11 Ā± 5.31%), and percentage of stenosis (18.20 Ā± 1.09% versus 30.58 Ā± 1.21%). Apparent vascular calcification was detected in medial layers at 6 weeks after balloon angioplasty, which may be associated with upregulation of bone morphogenetic protein-2 (BMP-2). Our data indicated that unselected BM-MSCs transfer may induce vascular remodeling and calcification after balloon injury in hyperlipidemic rats

    Statistical Detection of Collective Data Fraud

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    Statistical divergence is widely applied in multimedia processing, basically due to regularity and interpretable features displayed in data. However, in a broader range of data realm, these advantages may no longer be feasible, and therefore a more general approach is required. In data detection, statistical divergence can be used as a similarity measurement based on collective features. In this paper, we present a collective detection technique based on statistical divergence. The technique extracts distribution similarities among data collections, and then uses the statistical divergence to detect collective anomalies. Evaluation shows that it is applicable in the real world.Comment: 6 pages, 6 figures and tables, submitted to ICME 202

    BMPRIA mediated signaling is essential for temporomandibular joint development in mice

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    The central importance of BMP signaling in the development and homeostasis of synovial joint of appendicular skeleton has been well documented, but its role in the development of temporomandibular joint (TMJ), also classified as a synovial joint, remains completely unknown. In this study, we investigated the function of BMPRIA mediated signaling in TMJ development in mice by transgenic loss-of- and gain-of-function approaches. We found that BMPRIA is expressed in the cranial neural crest (CNC)-derived developing condyle and glenoid fossa, major components of TMJ, as well as the interzone mesenchymal cells. Wnt1-Cre mediated tissue specific inactivation of BmprIa in CNC lineage led to defective TMJ development, including failure of articular disc separation from a hypoplastic condyle, persistence of interzone cells, and failed formation of a functional fibrocartilage layer on the articular surface of the glenoid fossa and condyle, which could be at least partially attributed to the down-regulation of Ihh in the developing condyle and inhibition of apoptosis in the interzone. On the other hand, augmented BMPRIA signaling by Wnt1-Cre driven expression of a constitutively active form of BmprIa (caBmprIa) inhibited osteogenesis of the glenoid fossa and converted the condylar primordium from secondary cartilage to primary cartilage associated with ectopic activation of Smad-dependent pathway but inhibition of JNK pathway, leading to TMJ agenesis. Our results present unambiguous evidence for an essential role of finely tuned BMPRIA mediated signaling in TMJ development

    Direct and Indirect Effects of Urbanization on Energy Intensity in Chinese Cities: A Regional Heterogeneity Analysis

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    Energy intensity reduction has become a constrained target from the 11th five-year plan in China. Energy consumption is expected to increase because of rapid urbanization and economic growth, whereas energy intensity reduction is regarded as a method to alleviate the pressure of growing energy demand. An important contribution of this study is the investigation of urbanization impact on energy intensity across China at the urban level. This research uses a balanced panel data set of 224 cities for the period between 2005 and 2016 and reports deep insights into and innovative findings for the reduction of energy intensity across different regions and cities in China. To examine the direct, indirect, and total effects and regional heterogeneous effects, we employ spatial Durbin models and spatial decomposition techniques. It reveals significant and negative direct effects of urbanization in the western and full regions. However, the indirect and total effects of urbanization are significantly negative in the eastern and western regions. The pressure of urbanization on energy has alleviated and is reversing, especially under the construction of people-oriented and green new-type urbanization. The empirics highlight industrialization as a contributing factor for high energy intensity in the spatial outcomes of regional analysis. The direct effect of per capita GDP supports the existence of the inverted U-shaped relationship between economic development and energy intensity. The study proposes fruitful implications to construct new-type urbanization forenergy conservation and sustainable development in China
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