The planar force model of prepreg,initially established based on the principle of minimum potential energy and the Rayleigh-Ritz method,was improved by considering the difference between the tensile and compressive mo...The planar force model of prepreg,initially established based on the principle of minimum potential energy and the Rayleigh-Ritz method,was improved by considering the difference between the tensile and compressive moduli in the direction of the prepreg fibers.Compressivetensile stress distribution coefficients were also established.Combined with tests on the effect of process parameters on interlayer tack,a theoretical prediction model for the turning radius related to process parameters was developed,and the impact of prepreg interlayer tack force on the minimum turning radius was analyzed.A finite element simulation model for prepreg curve placement was created to study the size and distribution patterns of folds generated during the prepreg turning process.A minimum turning radius test was conducted to establish evaluation criteria for surface defects in curve placement and verify the accuracy of the minimum turning radius prediction model.Based on this,a prediction method for the minimum turning radius of prepreg related to process parameters was established,providing constraints for the trajectory design of variable-stiffness placement composites.展开更多
Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Usi...Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Using global datasets from Tallo(a tree allometry and crown architecture database encompassing thousands of species)and TRY(a plant traits database),we fit B ayesian hierarchical models with three alternative functional forms(powerlaw,generalized Michaelis-Menten(gMM),and Weibull)to characterize how diameter at breast height(DBH),tree height(H),and crown radius(CR)scale with and without wood density as a species-level predictor.Our analysis revealed that the saturating Weibull function best captured the relationship between tree height and DBH in both functional groups,whereas the CR-DBH relationship was best predicted by a power-law function in angiosperms and by the gMM function in gymnosperms.Although including wood density did not significantly improve predictive performance,it revealed important ecological trade-offs:lighter-wood angiosperms achieve taller mature heights more rapidly,and denser wood promotes wider crown expansion across clades.We also found that accurately estimating DBH required considering both height and crown size,highlighting how these variables together distinguish trees of similar height but differing trunk diameters.Our results emphasize the importance of applying saturating functions for large trees to improve forest biomass estimates and show that wood density,though not always predictive at broad scales,helps illuminate the biomechanical and ecological constraints underlying diverse tree architectures.These findings offer practical pathways for integrating height-and crown-based metrics into existing carbon monitoring programs worldwide.展开更多
In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizh...In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizhong Zhou,Hongxia Liu and Yang Xu(2022).Then,an A_(α)-spectral condition is given to ensure that G is a fractional ID-[a,b]-factor-critical covered graph and an(a,b,k)-factor-critical graph,respectively.In fact,(a,b,k)-factor-critical graph is a graph which has an[a,b]-factor for k=0.Thus,these above results extend the results of Jia Wei and Shenggui Zhang(2023)and Ao Fan,Ruifang Liu and Guoyan Ao(2023)in some sense.展开更多
BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appea...BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appears to provide limited additional benefit.AIM To determine the necessary number of follow-up X-rays to use resources efficiently.METHODS Participants included in this study are pediatric age group patients who were treated operatively for distal radius/both bone fractures and were identified from a prospected collected data from the operating room database between the years 2009 and 2017.The data in the study included patients who had distal radius fractures and underwent fixation surgery(n=88).RESULTS When assessing the difference in the odds of conducting 1 or less X-ray compared to 2 or more X-rays in regard to the type of fixation,the only significant difference is the closed reduction fixation method.Patients who underwent closed reduction method procedure have significantly lower odds of having 2 more X-rays compared to those who didn’t have closed reduction method.Open reduction,internal fixation,and other fixation methods(close reduction and internal fixation,debridement,or epiphysiodesis)have higher odds of having two or more X-rays compared to patients who did not receive these methods;however,these odds are not statistically significant.CONCLUSION The findings of this study reveal notable absence of a statistically significant association between the frequency of postoperative X-rays and the outcome of children with distal radius fractures.展开更多
This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh ...This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.展开更多
A graph G is H-free,if it contains no H as a subgraph.A graph G is said to be H-minor free,if it does not contain H as a minor.In 2010,Nikiforov asked that what the maximum spectral radius of an H-free graph of order ...A graph G is H-free,if it contains no H as a subgraph.A graph G is said to be H-minor free,if it does not contain H as a minor.In 2010,Nikiforov asked that what the maximum spectral radius of an H-free graph of order n is.In this paper,we consider some Brualdi-Solheid-Turan type problems on bipartite graphs.In 2015,Zhai,Lin and Gong in[Linear Algebra Appl.,2015,471:21-27]proved that if G is a bipartite graph with order n≥2k+2 and ρ(G)≥ρ(K_(k,n-k)),then G contains a C_(2k+2) unless G≌K_(k,n-k).First,we give a new and more simple proof for the above theorem.Second,we prove that if G is a bipartite graph with order n≥2k+2 and ρ(G)≥ρ(K_(k,n-k)),then G contains all T_(2k+3) unless G≌K_(k,n-k).Finally,we prove that among all outerplanar bipartite graphs on n≥308026 vertices,K_(1,n-1) attains the maximum spectral radius.展开更多
For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G)...For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).展开更多
For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant verti...For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.展开更多
Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of...Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.展开更多
The impact of aerosols on clouds,which remains one of the largest aspects of uncertainty in current weather forecasting and climate change research,can be influenced by various factors,such as the underlying surface t...The impact of aerosols on clouds,which remains one of the largest aspects of uncertainty in current weather forecasting and climate change research,can be influenced by various factors,such as the underlying surface type,cloud type,cloud phase,and aerosol type.To explore the impact of different underlying surfaces on the effect of aerosols on cloud development,this study focused on the Yangtze River Delta(YRD)and its offshore regions(YRD sea)for a comparative analysis based on multi-source satellite data,while also considering the variations in cloud type and cloud phase.The results show lower cloud-top height and depth of single-layer clouds over the ocean than land,and higher liquid cloud in spring over the ocean.Aerosols are found to enhance the cumulus cloud depth through microphysical effects,which is particularly evident over the ocean.Aerosols are also found to decrease the cloud droplet effective radius in the ocean region and during the mature stage of cloud development in the land region,while opposite results are found during the early stage of cloud development in the land region.The quantitative results indicate that the indirect effect is positive(0.05)in the land region at relatively high cloud water path,which is smaller than that in the ocean region(0.11).The findings deepen our understanding of the influence aerosols on cloud development and the mechanisms involved,which could then be applied to improve the ability to simulate cloud-associated weather processes.展开更多
Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechan...Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechanical properties, offers a reliable alternative. The aim of this study was to evaluate the radiological, the functional results and to determine the factors of poor postoperative prognosis of DRF treated with Newclip radial plates®. Methodology: This prospective cohort study evaluates the radiological and functional outcames of displaced radius fractures (DRFs) in patients ≥50 years old treated with Newclip® (locked anterior plates) at the Basse-Terre Hospital in Guadeloupe from 2022 to 2024. The patients were categorized into those with epiphyseal involvement (E1 - E4) and without epiphyseal involvement (E0) based on Laulan’s MEU classification. Radiological parameters (distal radio-ulnar index (DRUI), radial inclination frant view (IRF), radial inclination sagittal view (IRS) were assessed pre and post-operatively. Functional recovery was evaluated at 12 months using the QuickDash questionnaire. Results: Falls were the most common cause of fracture. Post-operatively, SRI was the least restored parameter. Poor prognostic factor for SRI improvement included posterior commimution and unstable fractures. Factors associated with higher QuickDash scores included unstable factures, unrestored DRUI, low plate position, metaphyseal features, and ulnar features. Conclusion: The anterior locking plate osteosynthesis is reliable treatment option with excellent functional outcomes.展开更多
In this paper, we will demonstrate that there is a link between cosmology and the Planck scale. It has, in recent years, been shown that the Planck length can be determined independently of G, ℏ, and c, and that a ser...In this paper, we will demonstrate that there is a link between cosmology and the Planck scale. It has, in recent years, been shown that the Planck length can be determined independently of G, ℏ, and c, and that a series of cosmological predictions can be derived solely from two constants, namely the Planck length and the speed of gravity. The speed of gravity can be easily determined without knowledge of the speed of light [1] [2]. This provides a new perspective on cosmology and demonstrates that there is a link between the Planck scale and cosmology. This is fully consistent with a recent quantization of general relativity theory that links general relativity to the Compton frequency and the Planck scale. We examine both the Friedmann cosmology and the recently introduced cosmology based on the extremal solution of the Reissner-Nordström, Kerr, and Kerr-Newman metric.1.展开更多
In the practice of pipeline transport of oil,oil products and gas to perform turns of trunk and field pipelines in vertical and horizontal planes are used bends of various designs such as:elbows with bending radius of...In the practice of pipeline transport of oil,oil products and gas to perform turns of trunk and field pipelines in vertical and horizontal planes are used bends of various designs such as:elbows with bending radius of 1.0DN or 1.5DN and standardized angles of 30°,45°,60°,90°;induction bends with bending angles from 1°to 90°;cold bends with bending angles depending on the nominal diameter DN.展开更多
Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases...Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases,adding unnecessary cost,radiation exposure,and clinical burden.A recent study highlights this issue and questions whether routine imaging truly benefits patient outcomes.As orthopedic care shifts toward more patient-centered and value-driven models,there is increasing support for the judicious use of radiographs,reserving imaging for cases where clinical examination or patient symptoms suggest a potential problem.This shift would reflect a broader movement within orthopedic practice:Aligning tradition with necessity,and optimizing care based on evidence rather than habit.展开更多
Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotop...Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.展开更多
BACKGROUND Supracondylar humeral fractures(SCHF)are the second most common fractures in childhood and can lead to short-and long-term complications.Despite their prevalence,the anatomical factors that predispose child...BACKGROUND Supracondylar humeral fractures(SCHF)are the second most common fractures in childhood and can lead to short-and long-term complications.Despite their prevalence,the anatomical factors that predispose children to SCHF remain unclear.This study aimed to determine whether there are significant morpho-logical differences in the elbow by comparing the radiographic angular measure-ments of the contralateral elbows of patients with SCHF to those of patients with distal radius fractures(DRF)and a healthy control group.We sought to explore if these morphological variations contribute to the occurrence of SCHF.Radiographs of 78 SCHF patients were analyzed for angular measurements of the contralateral elbow.Two control groups were used:98 healthy children and 40 patients with DRF.Angular measurements included Baumann angle(BA),hu-meroulnar angle(HUA),humerus metaphysis-diaphysis angle(HMDA),humerus shaft-condylar angle(HSCA),and lateral capitellohumeral angle.Only BA,HUA,and HMDA were measured in the DRF group.Statistical analysis was performed to compare differences among groups.RESULTS Significant differences were found in elbow measurements between SCHF and control groups(P<0.05).However,the mean values for all groups fell within the ranges described in the literature.CONCLUSION While statistically significant differences were found in elbow morphology between SCHF patients and controls,these differences don't translate into clinically meaningful morphological deviations.展开更多
A flexible sidetracking stimulation technology of horizontal wells is formed to develop the lateral deep remaining oil and gas resources of the low-permeability mature oilfields.This technology first uses the flexible...A flexible sidetracking stimulation technology of horizontal wells is formed to develop the lateral deep remaining oil and gas resources of the low-permeability mature oilfields.This technology first uses the flexible sidetracking tool to achieve low-cost sidetracking in the old wellbore,and then uses the hydraulic jet technology to induce multiple fractures to fracture.Finally,the bullhead fracturing of multi-cluster temporary plugging for the sidetracking hole is carried out by running the tubing string,to realize the efficient development of the remaining reserves among the wells.The flexible sidetracking stimulation technology involves flexible sidetracking horizontal wells drilling and sidetracking horizontal well fracturing.The flexible sidetracking horizontal well drilling includes three aspects:flexible drill pipe structure and material optimization,drilling technology,and sealed coring tool.The sidetracking horizontal well fracturing includes two aspects:fracturing scheme optimization,fracturing tools and implementation process optimization.The technology has been conducted several rounds of field tests in the Ansai Oilfield of Changqing,China.The results show that by changing well type and reducing row spacing of oil and water wells,the pressure displacement system can be well established to achieve effective pressure transmission and to achieve the purpose of increasing liquid production in low-yield and low-efficiency wells.It is verified that the flexible sidetracking stimulation technology can provide favorable support for accurately developing remaining reserves in low-permeability reservoirs.展开更多
Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakag...Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakage risk from deformed pipelines was developed.First,the pipe instability deformation limit was corrected by the multi-indicator optimized screening method proposed in this paper.Then,the leakage risk influence radius of the pipe segment was defined by the failure probability.Next,the pipe segment'deformation and strength were assessed sequentially using the ratio and point methods.Combining the fuzzy logic inference method with the assessment results as input variable,and the failure probabilities as output variable,a quantitative assessment model for the pipeline leakage risk was established.Accordingly,the risk range and level of adjacent coal mines and surfaces were divided,and the verification method and forward countermeasures were proposed.Finally,an engineering case was used for analysis and verification.The results show that the gas pipeline with 650 m length was divided into seven regions and four risk levels.The influence radius of the risk levels from low to high were 12.75 m,25.5 m,38.25 m,and 51 m,and the influence widths on the surface were 25.28 m,49.84 m,76.34 m,and 101.84 m,correspondingly.The nearest distances from the risk area to the mine and village were 212.65 m and 329.08 m.The assessment of potentially threatened areas is significantly simplified by the assessment model combined with pipeline deformation,which has great practical importance for risk management and disaster prevention in adjacent space.展开更多
Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respe...Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respectively.The spectral radius of A_(α)(G)is called byα-spectral radius of the graph G.In this paper,we study the perturbation of the complete multipartite graphsα-spectral radius when move a vertex from a part to other part of the complete multipartite graphs.Moreover,we give some conditions when theα-spectral Turán of graphs implies the Turán theorem of graphs.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.U24A20118,52175311,52175133,12472131,52405149)the Fundamental Research Funds for the Central Universities,China(Nos.JZ2023HGPB0289,JZ2023HGQA0475,PA2024GDSK0063)the Anhui Provincial Natural Science Foundation,China(No.2408085QE156)。
文摘The planar force model of prepreg,initially established based on the principle of minimum potential energy and the Rayleigh-Ritz method,was improved by considering the difference between the tensile and compressive moduli in the direction of the prepreg fibers.Compressivetensile stress distribution coefficients were also established.Combined with tests on the effect of process parameters on interlayer tack,a theoretical prediction model for the turning radius related to process parameters was developed,and the impact of prepreg interlayer tack force on the minimum turning radius was analyzed.A finite element simulation model for prepreg curve placement was created to study the size and distribution patterns of folds generated during the prepreg turning process.A minimum turning radius test was conducted to establish evaluation criteria for surface defects in curve placement and verify the accuracy of the minimum turning radius prediction model.Based on this,a prediction method for the minimum turning radius of prepreg related to process parameters was established,providing constraints for the trajectory design of variable-stiffness placement composites.
基金supported by the Xingdian Talent Support Program of Yunnan Province(E5YNR03B01)the Xishuangbanna State Rainforest Talent Support Program(E4BN041B01)the CAS President’s International Fellowship Initiative(2020FYB0003)。
文摘Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Using global datasets from Tallo(a tree allometry and crown architecture database encompassing thousands of species)and TRY(a plant traits database),we fit B ayesian hierarchical models with three alternative functional forms(powerlaw,generalized Michaelis-Menten(gMM),and Weibull)to characterize how diameter at breast height(DBH),tree height(H),and crown radius(CR)scale with and without wood density as a species-level predictor.Our analysis revealed that the saturating Weibull function best captured the relationship between tree height and DBH in both functional groups,whereas the CR-DBH relationship was best predicted by a power-law function in angiosperms and by the gMM function in gymnosperms.Although including wood density did not significantly improve predictive performance,it revealed important ecological trade-offs:lighter-wood angiosperms achieve taller mature heights more rapidly,and denser wood promotes wider crown expansion across clades.We also found that accurately estimating DBH required considering both height and crown size,highlighting how these variables together distinguish trees of similar height but differing trunk diameters.Our results emphasize the importance of applying saturating functions for large trees to improve forest biomass estimates and show that wood density,though not always predictive at broad scales,helps illuminate the biomechanical and ecological constraints underlying diverse tree architectures.These findings offer practical pathways for integrating height-and crown-based metrics into existing carbon monitoring programs worldwide.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11961041,12261055)the Key Project of Natural Science Foundation of Gansu Province(Grant No.24JRRA222)the Foundation for Innovative Fundamental Research Group Project of Gansu Province(Grant No.25JRRA805).
文摘In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizhong Zhou,Hongxia Liu and Yang Xu(2022).Then,an A_(α)-spectral condition is given to ensure that G is a fractional ID-[a,b]-factor-critical covered graph and an(a,b,k)-factor-critical graph,respectively.In fact,(a,b,k)-factor-critical graph is a graph which has an[a,b]-factor for k=0.Thus,these above results extend the results of Jia Wei and Shenggui Zhang(2023)and Ao Fan,Ruifang Liu and Guoyan Ao(2023)in some sense.
文摘BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appears to provide limited additional benefit.AIM To determine the necessary number of follow-up X-rays to use resources efficiently.METHODS Participants included in this study are pediatric age group patients who were treated operatively for distal radius/both bone fractures and were identified from a prospected collected data from the operating room database between the years 2009 and 2017.The data in the study included patients who had distal radius fractures and underwent fixation surgery(n=88).RESULTS When assessing the difference in the odds of conducting 1 or less X-ray compared to 2 or more X-rays in regard to the type of fixation,the only significant difference is the closed reduction fixation method.Patients who underwent closed reduction method procedure have significantly lower odds of having 2 more X-rays compared to those who didn’t have closed reduction method.Open reduction,internal fixation,and other fixation methods(close reduction and internal fixation,debridement,or epiphysiodesis)have higher odds of having two or more X-rays compared to patients who did not receive these methods;however,these odds are not statistically significant.CONCLUSION The findings of this study reveal notable absence of a statistically significant association between the frequency of postoperative X-rays and the outcome of children with distal radius fractures.
基金Supported by Natural Science Foundation of HuBei Province(2022CFB299).
文摘This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.
基金Supported by NSFC(No.12271162)Natural Science Foundation of Shanghai(No.22ZR1416300).
文摘A graph G is H-free,if it contains no H as a subgraph.A graph G is said to be H-minor free,if it does not contain H as a minor.In 2010,Nikiforov asked that what the maximum spectral radius of an H-free graph of order n is.In this paper,we consider some Brualdi-Solheid-Turan type problems on bipartite graphs.In 2015,Zhai,Lin and Gong in[Linear Algebra Appl.,2015,471:21-27]proved that if G is a bipartite graph with order n≥2k+2 and ρ(G)≥ρ(K_(k,n-k)),then G contains a C_(2k+2) unless G≌K_(k,n-k).First,we give a new and more simple proof for the above theorem.Second,we prove that if G is a bipartite graph with order n≥2k+2 and ρ(G)≥ρ(K_(k,n-k)),then G contains all T_(2k+3) unless G≌K_(k,n-k).Finally,we prove that among all outerplanar bipartite graphs on n≥308026 vertices,K_(1,n-1) attains the maximum spectral radius.
基金Supported by NSFC (Nos.12171089,12271235)NSF of Jiangsu (No.BK20190919)NSF of Fujian (No.2021J02048)。
文摘For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).
文摘For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.
基金Chongqing Fuling District Science and Health Joint Medical Research Project(2022KWLH069)。
文摘Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.
基金supported by the National Natural Science Foundation of China(Grant No.42230601).
文摘The impact of aerosols on clouds,which remains one of the largest aspects of uncertainty in current weather forecasting and climate change research,can be influenced by various factors,such as the underlying surface type,cloud type,cloud phase,and aerosol type.To explore the impact of different underlying surfaces on the effect of aerosols on cloud development,this study focused on the Yangtze River Delta(YRD)and its offshore regions(YRD sea)for a comparative analysis based on multi-source satellite data,while also considering the variations in cloud type and cloud phase.The results show lower cloud-top height and depth of single-layer clouds over the ocean than land,and higher liquid cloud in spring over the ocean.Aerosols are found to enhance the cumulus cloud depth through microphysical effects,which is particularly evident over the ocean.Aerosols are also found to decrease the cloud droplet effective radius in the ocean region and during the mature stage of cloud development in the land region,while opposite results are found during the early stage of cloud development in the land region.The quantitative results indicate that the indirect effect is positive(0.05)in the land region at relatively high cloud water path,which is smaller than that in the ocean region(0.11).The findings deepen our understanding of the influence aerosols on cloud development and the mechanisms involved,which could then be applied to improve the ability to simulate cloud-associated weather processes.
文摘Background and Objectives: The distal radius fracture (DRF) is a major public health problem in northern countries. Its frequency is constantly increasing. The locked anterior plate with its well-established biomechanical properties, offers a reliable alternative. The aim of this study was to evaluate the radiological, the functional results and to determine the factors of poor postoperative prognosis of DRF treated with Newclip radial plates®. Methodology: This prospective cohort study evaluates the radiological and functional outcames of displaced radius fractures (DRFs) in patients ≥50 years old treated with Newclip® (locked anterior plates) at the Basse-Terre Hospital in Guadeloupe from 2022 to 2024. The patients were categorized into those with epiphyseal involvement (E1 - E4) and without epiphyseal involvement (E0) based on Laulan’s MEU classification. Radiological parameters (distal radio-ulnar index (DRUI), radial inclination frant view (IRF), radial inclination sagittal view (IRS) were assessed pre and post-operatively. Functional recovery was evaluated at 12 months using the QuickDash questionnaire. Results: Falls were the most common cause of fracture. Post-operatively, SRI was the least restored parameter. Poor prognostic factor for SRI improvement included posterior commimution and unstable fractures. Factors associated with higher QuickDash scores included unstable factures, unrestored DRUI, low plate position, metaphyseal features, and ulnar features. Conclusion: The anterior locking plate osteosynthesis is reliable treatment option with excellent functional outcomes.
文摘In this paper, we will demonstrate that there is a link between cosmology and the Planck scale. It has, in recent years, been shown that the Planck length can be determined independently of G, ℏ, and c, and that a series of cosmological predictions can be derived solely from two constants, namely the Planck length and the speed of gravity. The speed of gravity can be easily determined without knowledge of the speed of light [1] [2]. This provides a new perspective on cosmology and demonstrates that there is a link between the Planck scale and cosmology. This is fully consistent with a recent quantization of general relativity theory that links general relativity to the Compton frequency and the Planck scale. We examine both the Friedmann cosmology and the recently introduced cosmology based on the extremal solution of the Reissner-Nordström, Kerr, and Kerr-Newman metric.1.
文摘In the practice of pipeline transport of oil,oil products and gas to perform turns of trunk and field pipelines in vertical and horizontal planes are used bends of various designs such as:elbows with bending radius of 1.0DN or 1.5DN and standardized angles of 30°,45°,60°,90°;induction bends with bending angles from 1°to 90°;cold bends with bending angles depending on the nominal diameter DN.
文摘Routine postoperative radiographs after surgical fixation of pediatric distal-radius fractures have long been part of standard care.Yet growing evidence shows that these images rarely change management in stable cases,adding unnecessary cost,radiation exposure,and clinical burden.A recent study highlights this issue and questions whether routine imaging truly benefits patient outcomes.As orthopedic care shifts toward more patient-centered and value-driven models,there is increasing support for the judicious use of radiographs,reserving imaging for cases where clinical examination or patient symptoms suggest a potential problem.This shift would reflect a broader movement within orthopedic practice:Aligning tradition with necessity,and optimizing care based on evidence rather than habit.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204412,12274423,12174402,12393821,and 12004124)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0920100 and XDB0920101)support from the Natural Sciences and Engineering Research Council of Canada.All calculations were performed on the APM-Theoretical Computing Cluster(APM-TCC).
文摘Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.
文摘BACKGROUND Supracondylar humeral fractures(SCHF)are the second most common fractures in childhood and can lead to short-and long-term complications.Despite their prevalence,the anatomical factors that predispose children to SCHF remain unclear.This study aimed to determine whether there are significant morpho-logical differences in the elbow by comparing the radiographic angular measure-ments of the contralateral elbows of patients with SCHF to those of patients with distal radius fractures(DRF)and a healthy control group.We sought to explore if these morphological variations contribute to the occurrence of SCHF.Radiographs of 78 SCHF patients were analyzed for angular measurements of the contralateral elbow.Two control groups were used:98 healthy children and 40 patients with DRF.Angular measurements included Baumann angle(BA),hu-meroulnar angle(HUA),humerus metaphysis-diaphysis angle(HMDA),humerus shaft-condylar angle(HSCA),and lateral capitellohumeral angle.Only BA,HUA,and HMDA were measured in the DRF group.Statistical analysis was performed to compare differences among groups.RESULTS Significant differences were found in elbow measurements between SCHF and control groups(P<0.05).However,the mean values for all groups fell within the ranges described in the literature.CONCLUSION While statistically significant differences were found in elbow morphology between SCHF patients and controls,these differences don't translate into clinically meaningful morphological deviations.
基金Supported by the National Key Research and Development Program of China(2023YFF0615403)CNPC Science and Technology Project(2023ZZ0803).
文摘A flexible sidetracking stimulation technology of horizontal wells is formed to develop the lateral deep remaining oil and gas resources of the low-permeability mature oilfields.This technology first uses the flexible sidetracking tool to achieve low-cost sidetracking in the old wellbore,and then uses the hydraulic jet technology to induce multiple fractures to fracture.Finally,the bullhead fracturing of multi-cluster temporary plugging for the sidetracking hole is carried out by running the tubing string,to realize the efficient development of the remaining reserves among the wells.The flexible sidetracking stimulation technology involves flexible sidetracking horizontal wells drilling and sidetracking horizontal well fracturing.The flexible sidetracking horizontal well drilling includes three aspects:flexible drill pipe structure and material optimization,drilling technology,and sealed coring tool.The sidetracking horizontal well fracturing includes two aspects:fracturing scheme optimization,fracturing tools and implementation process optimization.The technology has been conducted several rounds of field tests in the Ansai Oilfield of Changqing,China.The results show that by changing well type and reducing row spacing of oil and water wells,the pressure displacement system can be well established to achieve effective pressure transmission and to achieve the purpose of increasing liquid production in low-yield and low-efficiency wells.It is verified that the flexible sidetracking stimulation technology can provide favorable support for accurately developing remaining reserves in low-permeability reservoirs.
基金funded by the National Natural Science Foundation of China(52225402 and 51874312)the Major scientific and technological innovation project of Shandong Province(2019SDZY01 and 2019SDZY02).
文摘Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakage risk from deformed pipelines was developed.First,the pipe instability deformation limit was corrected by the multi-indicator optimized screening method proposed in this paper.Then,the leakage risk influence radius of the pipe segment was defined by the failure probability.Next,the pipe segment'deformation and strength were assessed sequentially using the ratio and point methods.Combining the fuzzy logic inference method with the assessment results as input variable,and the failure probabilities as output variable,a quantitative assessment model for the pipeline leakage risk was established.Accordingly,the risk range and level of adjacent coal mines and surfaces were divided,and the verification method and forward countermeasures were proposed.Finally,an engineering case was used for analysis and verification.The results show that the gas pipeline with 650 m length was divided into seven regions and four risk levels.The influence radius of the risk levels from low to high were 12.75 m,25.5 m,38.25 m,and 51 m,and the influence widths on the surface were 25.28 m,49.84 m,76.34 m,and 101.84 m,correspondingly.The nearest distances from the risk area to the mine and village were 212.65 m and 329.08 m.The assessment of potentially threatened areas is significantly simplified by the assessment model combined with pipeline deformation,which has great practical importance for risk management and disaster prevention in adjacent space.
基金The National Science Foundation of China(12371349,12471331)。
文摘Let G be a graph andαÎ[0,1),Nikiforov merged the adjacency matrix and the signless Laplacian matrix to A_(α)(G)=αD(G)+(1-α)A(G),where D(G)A(G)are the degree diagonal matrix and the adjacency matrix of G,respectively.The spectral radius of A_(α)(G)is called byα-spectral radius of the graph G.In this paper,we study the perturbation of the complete multipartite graphsα-spectral radius when move a vertex from a part to other part of the complete multipartite graphs.Moreover,we give some conditions when theα-spectral Turán of graphs implies the Turán theorem of graphs.
