Urban forests are highly multifunctional and provide numerous ecological functions.Plant functional traits individually or jointly influence the ecological multifunctionality of tree species(TS-EMF)and can also modify...Urban forests are highly multifunctional and provide numerous ecological functions.Plant functional traits individually or jointly influence the ecological multifunctionality of tree species(TS-EMF)and can also modify TSEMF in response to environmental changes.However,there has been limited exploration of multitrait combinations for predicting TS-EMF across seasons and of trait thresholds that enhance TS-EMF.Here,for 10 dominant tree species in urban forests of Northeast China,14 traits were measured and four aboveground and three belowground ecological functions assessed in three seasons.Ecological functions and TS-EMF differed significantly throughout the seasons(P<0.05).Synergistic relationships were found between carbon sequestration and oxygen release,between cooling and humidification,and between organic carbon accumulation and nutrient cycling.Notably,aboveground multifunctionality played a leading role in TS-EMF.With seasonal changes,resource allocation shifted toward traits related to resource acquisition rather than conservation to maintain TS-EMF.The combination of traits that predicted TS-EMF varied by type,accounting for up to 66.45%of the variation.TS-EMF was primarily driven by leaf structure in spring and by nutrient accumulation in autumn.Leaf carbon content(LCC)consistently served as a stabilizing factor for predicting TS-EMF across seasons.At 36.5-36.8 mg g^(-1),LCC had its optimal effect on TS-EMF.Other traits in combination that positively influence total TS-EMF include leaf nitrogen content(3.43-3.45 mg g^(-1)),leaf phosphorus content(0.80-0.83 mg g^(-1)),and leaf area(65.86-68.43 cm^(2)).Within these specified trait thresholds,Morus alba and Quercus mongolica were identified as key species.These findings suggest that the trade-off between various ecological functions can be managed by altering plant traits across seasons.This approach could provide a theoretical foundation for enhancing the TS-EMF of urban forests through trait-based management,offering practical guidance for selecting tree species.展开更多
A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that r...A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that regulates heading date,plant height and grain number.Here,we investigated the relationship between Ghd7 and florigen genes Hd3a and RFT1,to determine their roles in regulating heading date and grain number under different photoperiods.Our results revealed that under long-day(LD)conditions,Hd3a acts prior to RFT1 to promote heading while negatively regulating plant height and grain number.In contrast,Ghd7 positively regulates heading date,plant height,and grain number by inhibiting both Hd3a and RFT1.Under short-day(SD)conditions,the functions of Hd3a and RFT1 remain consistent with those under LD conditions,but Ghd7 does not inhibit their expression,resulting in a weaker phenotypic effect compared to Hd3a.Additionally,under both LD and SD conditions,increased Ghd7 expression enhances its inhibitory effect on Hd3a and RFT1,leading to later heading and increased grain number;however,once the heading date exceeds 94 d,grain number no longer increases.Moreover,the gn1a allele increased grain number by 16.5%to 42.5%,while combinations of the elite alleles from Ghd7,Hd3a,RFT1,and Gn1a significantly increased grain number by up to 240.9%.Therefore,we propose a new breeding strategy to optimize the heading date and grain number using the Ghd7Hd3aRFT1gn1a combination of Ghd7,Hd3a,RFT1,and Gn1a under LD conditions,and the Ghd7hd3aRFT1gn1a combination under SD conditions.This strategy improved the yield of the high-quality Northeast variety Kongyu 131(KY131)by 69.1%in Beijing and 93.7%in Hainan.This strategy will greatly improve the efficiency of north-to-south adaptation in rice,providing theoretical guidance for expanding the geographical adaptability of rice varieties.展开更多
Recently,Choe-Koo-Wang(J Funct Anal,2020,278)demonstrated the rigid phenomenon:The compact linear combination of composition operators under the Coefficient Non-cancellation Condition(CNC),implies that each difference...Recently,Choe-Koo-Wang(J Funct Anal,2020,278)demonstrated the rigid phenomenon:The compact linear combination of composition operators under the Coefficient Non-cancellation Condition(CNC),implies that each difference is compact on the weighted Bergman space in the unit disk.Motivated by the subtle connection of composition operator theory on the weighted Bergman spaces,Korenblum spaces and bounded holomorphic function spaces,we first explore the rigid phenomenon which also holds on the Korenblum space over the unit ball.Furthermore,we discuss which difference of composition operators is compact when the compact combination of composition operators does not satisfy the condition(CNC)on Korenblum spaces and bounded holomorphic function spaces over the unit ball setting.展开更多
Effective isolation between the cement sheath and the sandstone is crucial for the development and production of oil and gas wells in sandstone formations.In this study,a cement-sandstone composite(CSC)was prepared,an...Effective isolation between the cement sheath and the sandstone is crucial for the development and production of oil and gas wells in sandstone formations.In this study,a cement-sandstone composite(CSC)was prepared,and based onμ-CT three-dimensional reconstruction imaging and finite element analysis(FEA)techniques,the stress distribution and potential failure mechanism at the cement-sandstone bonding interface under axial loading were analyzed.The key findings are as follows:(1)stress concentrations are highly likely to form at the gap between the cement and sandstone interface and around interfacial voids,with Von Mises stress reaching critical levels of 18.0-20.0 MPa at these locations,significantly exceeding the stress magnitudes in well-bonded regions;(2)the phenomenon of local stress concentration driven by interfacial defects can be identified as the main basis for predicting damage location in interfacial debonding and continuous shear under axial load;(3)ensuring tight cementation at the cement-sandstone interface and minimizing interfacial voids are paramount for preventing stress-induced failure;(4)the critical Von Mises stress value of 20 MPa at the interface defect can be used as a benchmark for material selection and designed to ensure long-term integrity in oil and gas well applications subjected to similar axial loads.These findings contribute to a more accurate understanding of the failure mechanism of the cement-sandstone interface and to the precise design of material properties,thereby ensuring the long-term integrity of oil and gas well applications subjected to similar axial loads.展开更多
Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic beh...Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic behaviors of these combinations,especially the mechanism of action of prestressed bolts,still need to be further investigated.This study carried out split Hopkinson pressure bar(SHPB)tests on three sets of coal-rock(CR),CRB,and coal-rock-prestressed bolt(CRPB)combinations with different interface angles(β=15°,30°,45°,and 60°).The dynamic properties of the combinations were analyzed based on the stress-strain curve,energy dissipation,dynamic strength,fractal dimension of cracks,and failure mode of bolts.The test results show that a larger β will affect the stress transfer and anti-sliding ability of CR,resulting in a decrease in CR strength.The anchoring force of the bolt effectively suppresses the slip feature of CRB at the yield stage.As the strain rate increases,CRB shows a more pronounced'sudden increase'in strength,and the bolt significantly enhances its dynamic strength.The prestressed bolts enhance the dynamic strength of CRPB while weaken the effect of β.The fractal dimension of the macrocracks increases with strain rate,with smaller variations in CRB and CRPB,indicating that the bolt reduces the complexity degree of CRB and CRPB.The anchoring force of CRB depends on bolt strength,which reduces the slip along the interface.The anchoring force of CRPB balances the coal-rock slip and suppresses crack formation,resulting in a more cohesive response under dynamic load.展开更多
Background:Human skin is affected by ultraviolet rays on a daily basis,and excessive ultraviolet radiation(UVR)can lead to sunburn erythema,tanning,photoaging,and skin tumors.The combination of Astragali Radix(AR)and ...Background:Human skin is affected by ultraviolet rays on a daily basis,and excessive ultraviolet radiation(UVR)can lead to sunburn erythema,tanning,photoaging,and skin tumors.The combination of Astragali Radix(AR)and Anemarrhenae Rhizoma(AAR)is a common pairing in traditional Chinese medicine(TCM).According to earlier studies,they possess properties capable of alleviating the adverse impacts of UVR on the skin.However,the specific actions and underlying mechanisms require further investigation.The study aims to analyze the efficacy of AR-AAR in preventing UVR-induced skin damage and to clarify the associated molecular mechanisms.Methods:Potential signaling pathways by which AR and AAR may protect against UVR-induced skin damage were identified with network pharmacology,molecular docking techniques and molecular dynamics(MD)simulation.Except the normal group,the back skin of SD rats was exposed to 1.1 mW/cm^(2) UVA combined with 0.1 mW/cm^(2) UVB daily,and the UVR skin damage model was established.Morphological features of skin tissues of different groups were discovered through Hematoxylin and Eosin(HE)staining,Masson staining,Weigert staining.ELISA was utilized to measure the levels of reactive oxygen species(ROS),Interleukin 6(IL-6),Interleukin 1β(IL-1β)and Tumor necrosis factos-α(TNF-α)in skin tissues.RT-PCR and Western blot were employed to quantify the mRNA and protein contents of PI3K,AKT,and MMP-9.Results:Network pharmacology analysis predicts that AR-AAR may improve skin damage induced by UVR through the PI3K/AKT signaling pathway.Histological staining shows that AR-AAR can significantly reduce inflammatory infiltration and fibrosis in damaged skin.Treatment with AR-AAR(2:1)significantly reduced the expression levels of IL-1β,IL-6,TNF-αand ROS in UVR-damaged rat skin.After treatment with AR-AAR(2:1),not only did the relative mRNA expression levels of PI3K and AKT and the protein expression levels of PI3K,AKT,P-PI3K,and P-AKT increase,but the mRNA and protein expression levels of MMP-9 decreased.Conclusion:The study indicate that the AR-AAR combination and its active components may mitigate UVR skin damage by modulating the PI3K/AKT signaling pathway.展开更多
Mango is a plant with high economic value in the agricultural industry;thus,it is necessary to maximize the productivity performance of the mango plant,which can be done by implementing artificial intelligence.In this...Mango is a plant with high economic value in the agricultural industry;thus,it is necessary to maximize the productivity performance of the mango plant,which can be done by implementing artificial intelligence.In this study,a lightweight object detection model will be developed that can detect mango plant conditions based on disease potential,so that it becomes an early detection warning system that has an impact on increasing agricultural productivity.The proposed lightweight model integrates YOLOv7-Tiny and the proposed modules,namely the C2S module.The C2S module consists of three sub-modules such as the convolutional block attention module(CBAM),the coordinate attention(CA)module,and the squeeze-and-excitation(SE)module.The dataset is constructed by eight classes,including seven classes of disease conditions and one class of health conditions.The experimental result shows that the proposed lightweight model has the optimal results,which increase by 13.15% of mAP50 compared to the original model YOLOv7-Tiny.While the mAP50:95 also achieved the highest results compared to other models,including YOLOv3-Tiny,YOLOv4-Tiny,YOLOv5,and YOLOv7-Tiny.The advantage of the proposed lightweightmodel is the adaptability that supports it in constrained environments,such as edge computing systems.This proposedmodel can support a robust,precise,and convenient precision agriculture system for the user.展开更多
The internal flow fields within a three-dimensional inward-tunning combined inlet are extremely complex,especially during the engine mode transition,where the tunnel changes may impact the flow fields significantly.To...The internal flow fields within a three-dimensional inward-tunning combined inlet are extremely complex,especially during the engine mode transition,where the tunnel changes may impact the flow fields significantly.To develop an efficient flow field reconstruction model for this,we present an Improved Conditional Denoising Diffusion Generative Adversarial Network(ICDDGAN),which integrates Conditional Denoising Diffusion Probabilistic Models(CDDPMs)with Style GAN,and introduce a reconstruction discrimination mechanism and dynamic loss weight learning strategy.We establish the Mach number flow field dataset by numerical simulation at various backpressures for the mode transition process from turbine mode to ejector ramjet mode at Mach number 2.5.The proposed ICDDGAN model,given only sparse parameter information,can rapidly generate high-quality Mach number flow fields without a large number of samples for training.The results show that ICDDGAN is superior to CDDGAN in terms of training convergence and stability.Moreover,the interpolation and extrapolation test results during backpressure conditions show that ICDDGAN can accurately and quickly reconstruct Mach number fields at various tunnel slice shapes,with a Structural Similarity Index Measure(SSIM)of over 0.96 and a Mean-Square Error(MSE)of 0.035%to actual flow fields,reducing time costs by 7-8 orders of magnitude compared to Computational Fluid Dynamics(CFD)calculations.This can provide an efficient means for rapid computation of complex flow fields.展开更多
Objective To observe the influence of different acupoint combinations on immediate effect of surface electromyography of patients with cervical spondylosis, and to explore the interactions and laws among different acu...Objective To observe the influence of different acupoint combinations on immediate effect of surface electromyography of patients with cervical spondylosis, and to explore the interactions and laws among different acupoint combinations. Methods Acupuncture in three kinds of different acupoint combinations was conducted on 90 patients with cervical spondylosis（three groups）： group A [distal point selection group： Kūnlún（昆仑 BL 60） and Hòuxī（后溪 SI 3）]; group B [local point selection group： Fēngchí（风池 GB 20） and Tiānzhù（天柱 BL 10）]; group C（distal and local point selection group： BL 60, SI 3, GB 20 and BL 10）. Self control before and after treatment was adopted to observe the mean value of surface electromyography（SEMG） amplitude, to measure the mean values of integrated electromyography（IEMG） and electromyography root mean square（RMS）, and to calculate the variation rate of electromyography amplitude of trapezius on the affected side of patients before and after acupuncture. The differences of influences of different acupoint combinations on immediate effect of surface electromyography were compared intra-group, and the differences among the three groups after acupuncture were also compared. Results According to the intragroup comparison before and after acupuncture, the differences of mean value of electromyography amplitude, variation rate of electromyography amplitude, IEMG and RMS were both statistically significant（all P〈0.05）. According to the inter-group comparison after acupuncture, the mean value of electromyography amplitude, variation rate of electromyography amplitude, IEMG and RMS varied in different degrees, however, the differences were not significant（all P〉0.05）; there was no significant difference in the total effective rate among the three groups（P〉0.05）. Conclusion Acupuncture treatment in different acupoint combinations can increase IEMG and RMS and reduce mean value of electromyography amplitude and variation rate of electromyography amplitude, enhance cervical vertebral stability and active contractility of muscle fiber, and improve the fatigue resistance of neck flexion; while, the therapeutic effect of acupuncture on cervical spondylosis has nothing to do with the distance or the number of selected acupoint.展开更多
During 2000-2013, totally ten high-amylose specific hybrid rice combinations approved and five combinations for production test were bred in Sichuan Province. In the paper, rice yield, economic traits, quality indicat...During 2000-2013, totally ten high-amylose specific hybrid rice combinations approved and five combinations for production test were bred in Sichuan Province. In the paper, rice yield, economic traits, quality indicators and rice blast-resistance identification results of these 15 hybrid combinations were described and analyzed. Results show that Chuanxiangyou37 and Tianlongyou540 have relatively high amylose content, good yielding ability, high resistance and appropriate growth period, which are new hybrid rice varieties with organic combination of high amylase content, high gel consistency, high yield, stable yield and wide adaptability. Therefore, Chuanxiangyou37 and Tianlongyou540 are recommended as the main combination for rice production.展开更多
Programmed cell death 1（PD-1）/programmed cell death 1 ligand（PD-L1） blockade has shown promising effects in cancer immunotherapy. Removing the so-called ＂brakes＂ on T cell immune responses by blocking the PD-1/P...Programmed cell death 1（PD-1）/programmed cell death 1 ligand（PD-L1） blockade has shown promising effects in cancer immunotherapy. Removing the so-called ＂brakes＂ on T cell immune responses by blocking the PD-1/PDL1 check point should boost anti-tumor immunity and provide durable tumor regression for cancer patients.However, 30%–60% of patients show no response to PD-1/PD-L1 blockade. Thus, it is urgent to explore the underlying resistance mechanisms to improve sensitivity to anti-PD-1/PD-L1 therapy. We propose that the mechanisms promoting resistance mainly include T cell exclusion or exhaustion at the tumor site,immunosuppressive factors in the tumor microenvironment（TME）, and a range of tumor-intrinsic factors. This review highlights the power of studying the cellular and molecular mechanisms of resistance to improve the rational design of combination therapeutic strategies that can be translated to the clinic. Here, we briefly discuss the development of PD-1/PD-L1 blockade agents and focus on the current issues and future prospects for potential combinatorial therapeutic strategies that include anti-PD-1/PD-L1 therapy, based upon the available preclinical and clinical data.展开更多
Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock...Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock combinations. Fifty-four coal–rock combinations were prepared and split equally into groups containing different moisture contents(dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal–rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal–rock combinations and laws of crack propagation.展开更多
The invertibility of combinations of two orthogonal projectors aP ＋ bQ - cPQ - dQP is researched by using the CSdecomposition of matrices and properties of orthogonal projectors. The Moore-enrose inverse of the combi...The invertibility of combinations of two orthogonal projectors aP ＋ bQ - cPQ - dQP is researched by using the CSdecomposition of matrices and properties of orthogonal projectors. The Moore-enrose inverse of the combinations is presented under some special conditions.展开更多
In this paper we give equivalent theorems on simultaneous approximation for the combinations of Bernstein operators by r-th Ditzian- Totik modulus of smoothness w^rφλ （f, t）（0 ≤ λ≤ 1）. We also investigate th...In this paper we give equivalent theorems on simultaneous approximation for the combinations of Bernstein operators by r-th Ditzian- Totik modulus of smoothness w^rφλ （f, t）（0 ≤ λ≤ 1）. We also investigate the relation between the derivatives of the combinations of Bernstein operators and the smoothness of derivatives of functions.展开更多
There have been exponential gains in immuno-oncology in recent times through the development of immune checkpoint inhibitors. Already approved by the U.S. Food and Drug Administration for advanced melanoma and non-sma...There have been exponential gains in immuno-oncology in recent times through the development of immune checkpoint inhibitors. Already approved by the U.S. Food and Drug Administration for advanced melanoma and non-small cell lung cancer,immune checkpoint inhibitors also appears to have significant antitumor activity in multiple other tumor types. An exciting component of immunotherapy is the durability of antitumor responses observed, with some patients achieving disease control for many years. Nevertheless, not all patients benefit, and efforts should thus now focus on improving the efficacy of immunotherapy through the use of combination approaches and predictive biomarkers of response and resistance. There are multiple potential rational combinations using an immunotherapy backbone, including existing treatments such as radiotherapy, chemotherapy or molecularly targeted agents, as well as other immunotherapeutics. The aim of such antitumor strategies will be to raise the tail on the survival curve by increasing the number of long term survivors, while managing any additive or synergistic toxicities that may arise with immunotherapy combinations. Rational trial designs based on a clear understanding of tumor biology and drug pharmacology remain paramount. This article reviews the biology underpinning immuno-oncology, discusses existing and novel immunotherapeutic combinations currently in development, the challenges of predictive biomarkers of response and resistance and the impact of immuno-oncology on early phase clinical trial design.展开更多
The purpose of this paper is to characterize the pointwise rate of convergence for the combinations of Szász-Mirakjan operators using Ditzian-Totik modulus of smoothness.
Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechani...Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechanism and therapeutic strategies have not been clarified.This study aimed to identify potential roles of mi RNA/m RNA axis in the pathogenesis and drug combinations in the treatment of NASH.Methods:Microarray GSE59045 and GSE48452 were downloaded from the Gene Expression Omnibus and analyzed using R.Then we obtained differentially expressed genes(DE-genes).DAVID database was used for Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment pathway analysis.Protein-protein interaction(PPI)networks were used for the identification of hub genes.We found upstream regulators of hub genes using mi RTar Base.The expression and correlation of key mi RNA and its targets were detected by q PCR.Drug Pair Seeker was employed to predict drug combinations against NASH.The expression of mi RNA and hub genes in HCC was identified in the Cancer Genome Atlas database and Human Protein Atlas database.Results:Ninety-four DE-genes were accessed.GO and KEGG analysis showed that these predicted genes were linked to lipid metabolism.Eleven genes were identified as hub genes in PPI networks,and they were highly expressed in cells with vigorous lipid metabolism.hsa-mi R-335-5 p was the upstream regulator of 9 genes in the 11 hub genes,and it was identified as a key mi RNA.The hub genes were highly expressed in NASH models,while hsa-mi R-335-5 p was lowly expressed.The correlation of mi RNA-m RNA was established by q PCR.Functional verification indicated that hsa-mi R-335-5 p had inhibitory effect on the development of NASH.Finally,drug combinations were predicted and the expression of mi RNA and hub genes in HCC was identified.Conclusions:In the study,potential mi RNA-m RNA pathways related to NASH were identified.Targeting these pathways may be novel strategies against NASH.展开更多
[Objective] The aim of this study was to investigate the production performance of three pig cultivars through their fattening performance, carcass traits and meat quality for facilitating its application in practical...[Objective] The aim of this study was to investigate the production performance of three pig cultivars through their fattening performance, carcass traits and meat quality for facilitating its application in practical production. [ Method] Three pig cultivars were selected including Yesong （ F1 hybrid of pure-bred wild boar cross with songliao black sow as female parent） hybrid pigs, D × L × Y pigs from three-way cross and L x Y pigs from two-way cross. The test pigs in early period （before 60 kg） and late period （after 60 kg） were all fed with diets of the same nutritional level by free feeding and drinking water. The pre-test period was 3 d, while the test period was 120 d. Every 30 days, pigs with an empty stomach were weighed on morning, and when fattening to 120 d, five pigs with good growth and development in each cultivar were selected for slaughter to determine carcass traits and meat quality. [ Result] Under the same diets and feeding conditions, average daily gain and weight gain in the whole period of pigs from three-way cross were all significantly higher than those of pigs from two-way cross, and also extremely higher than those of Yesong pigs. There was no difference in dressed carcass percentage, backfat thickness and proportion of hind leg among three hybrid combinations. Lean meat percentage and eye muscle area of pigs from three-way cross and pigs from two-way cross were all significantly higher than those of Yesong pigs. Yesong pigs had relatively darker carnation, but marble vein （P〈0.05） and water loss rate （P〈0. 01 ） of Yesong pigs were relatively fewer than those of pigs from two-way cross and pigs from three-way cross. Shear force of Yesong pigs was significantly higher than that of pigs from two-way cross and pigs from three-way cross, [ Conclusion] Yesong hybrid pigs make full use of heterosis between wild pigs and Songliao black pigs for improvement of its meat quality, but some values of major economic traits in Yesong hybrid pigs is still lower than those in pigs from thrae-way cross and pigs from two-way cress.展开更多
In this paper, linear combinations of composition operators acting on weighted Dirichlet spaces are studied. By using the first derivative of the kernel function, we obtain a lower estimate for the essential norms of ...In this paper, linear combinations of composition operators acting on weighted Dirichlet spaces are studied. By using the first derivative of the kernel function, we obtain a lower estimate for the essential norms of these operators acting on the Dirichlet space D and S2. For general weighted Dirichlet space, by using complex interpolation methods, we characterize the compactness of these operators induced by linear fractional self-maps of the disk.展开更多
GPS positioning precision is affected by various error sources, and traditional combinations of GPS carrier phase observations have their own limitations such as the wide-lane, the narrow-lane and the ionospheric-free...GPS positioning precision is affected by various error sources, and traditional combinations of GPS carrier phase observations have their own limitations such as the wide-lane, the narrow-lane and the ionospheric-free combinations. To obtain the optimal positioning precision, a new linear combination method is addressed through the variance-covariance （VCV） of the GPS multi-frequency carrier phase combination equations, and the impact of the positioning precision is analyzed with the changing of the observation errors deduced by the law of error propagation. For the high precision positioning with only one carrier phase combination, the optimal combination method is deduced and further validated by an example of a baseline resolution with 60 km length. The result indicates that this method is the simplest, and the positioning precision is the best. Therefore, it is useful for long baseline quick positioning for different precision requirements in various distances.展开更多
基金supported by the National Natural Science Foundation(32130068,32271634,and 32071597)CAS Key Laboratory of Forest Ecology and Silviculture,Institute of Applied Ecology,Chinese Academy of Sciences(KLFES-2025)。
文摘Urban forests are highly multifunctional and provide numerous ecological functions.Plant functional traits individually or jointly influence the ecological multifunctionality of tree species(TS-EMF)and can also modify TSEMF in response to environmental changes.However,there has been limited exploration of multitrait combinations for predicting TS-EMF across seasons and of trait thresholds that enhance TS-EMF.Here,for 10 dominant tree species in urban forests of Northeast China,14 traits were measured and four aboveground and three belowground ecological functions assessed in three seasons.Ecological functions and TS-EMF differed significantly throughout the seasons(P<0.05).Synergistic relationships were found between carbon sequestration and oxygen release,between cooling and humidification,and between organic carbon accumulation and nutrient cycling.Notably,aboveground multifunctionality played a leading role in TS-EMF.With seasonal changes,resource allocation shifted toward traits related to resource acquisition rather than conservation to maintain TS-EMF.The combination of traits that predicted TS-EMF varied by type,accounting for up to 66.45%of the variation.TS-EMF was primarily driven by leaf structure in spring and by nutrient accumulation in autumn.Leaf carbon content(LCC)consistently served as a stabilizing factor for predicting TS-EMF across seasons.At 36.5-36.8 mg g^(-1),LCC had its optimal effect on TS-EMF.Other traits in combination that positively influence total TS-EMF include leaf nitrogen content(3.43-3.45 mg g^(-1)),leaf phosphorus content(0.80-0.83 mg g^(-1)),and leaf area(65.86-68.43 cm^(2)).Within these specified trait thresholds,Morus alba and Quercus mongolica were identified as key species.These findings suggest that the trade-off between various ecological functions can be managed by altering plant traits across seasons.This approach could provide a theoretical foundation for enhancing the TS-EMF of urban forests through trait-based management,offering practical guidance for selecting tree species.
基金supported by grants from the Chinese Academy of Sciences(XDA24010101)the Biological Breeding-National Science and Technology Major Project(2024ZD04077)+2 种基金the National Key Research and Development Program of China(2023YFF1001200)Natural Science Foundation of Zhejiang Province(LD24C130001)the Agricultural Science and Technology Innovation Program(ASTIP)of CAAS。
文摘A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that regulates heading date,plant height and grain number.Here,we investigated the relationship between Ghd7 and florigen genes Hd3a and RFT1,to determine their roles in regulating heading date and grain number under different photoperiods.Our results revealed that under long-day(LD)conditions,Hd3a acts prior to RFT1 to promote heading while negatively regulating plant height and grain number.In contrast,Ghd7 positively regulates heading date,plant height,and grain number by inhibiting both Hd3a and RFT1.Under short-day(SD)conditions,the functions of Hd3a and RFT1 remain consistent with those under LD conditions,but Ghd7 does not inhibit their expression,resulting in a weaker phenotypic effect compared to Hd3a.Additionally,under both LD and SD conditions,increased Ghd7 expression enhances its inhibitory effect on Hd3a and RFT1,leading to later heading and increased grain number;however,once the heading date exceeds 94 d,grain number no longer increases.Moreover,the gn1a allele increased grain number by 16.5%to 42.5%,while combinations of the elite alleles from Ghd7,Hd3a,RFT1,and Gn1a significantly increased grain number by up to 240.9%.Therefore,we propose a new breeding strategy to optimize the heading date and grain number using the Ghd7Hd3aRFT1gn1a combination of Ghd7,Hd3a,RFT1,and Gn1a under LD conditions,and the Ghd7hd3aRFT1gn1a combination under SD conditions.This strategy improved the yield of the high-quality Northeast variety Kongyu 131(KY131)by 69.1%in Beijing and 93.7%in Hainan.This strategy will greatly improve the efficiency of north-to-south adaptation in rice,providing theoretical guidance for expanding the geographical adaptability of rice varieties.
基金supported by National Science Foundations of China(Grant No.11771340,12171373).
文摘Recently,Choe-Koo-Wang(J Funct Anal,2020,278)demonstrated the rigid phenomenon:The compact linear combination of composition operators under the Coefficient Non-cancellation Condition(CNC),implies that each difference is compact on the weighted Bergman space in the unit disk.Motivated by the subtle connection of composition operator theory on the weighted Bergman spaces,Korenblum spaces and bounded holomorphic function spaces,we first explore the rigid phenomenon which also holds on the Korenblum space over the unit ball.Furthermore,we discuss which difference of composition operators is compact when the compact combination of composition operators does not satisfy the condition(CNC)on Korenblum spaces and bounded holomorphic function spaces over the unit ball setting.
基金supported by the National Natural Science Foundation of China(No.52274026)the National Key Research and Development Program(No.2022YFC2806504)the CNOOC Research Project(No.KJGG-2022-17-04 and NO.KJGG-2022-17-05).
文摘Effective isolation between the cement sheath and the sandstone is crucial for the development and production of oil and gas wells in sandstone formations.In this study,a cement-sandstone composite(CSC)was prepared,and based onμ-CT three-dimensional reconstruction imaging and finite element analysis(FEA)techniques,the stress distribution and potential failure mechanism at the cement-sandstone bonding interface under axial loading were analyzed.The key findings are as follows:(1)stress concentrations are highly likely to form at the gap between the cement and sandstone interface and around interfacial voids,with Von Mises stress reaching critical levels of 18.0-20.0 MPa at these locations,significantly exceeding the stress magnitudes in well-bonded regions;(2)the phenomenon of local stress concentration driven by interfacial defects can be identified as the main basis for predicting damage location in interfacial debonding and continuous shear under axial load;(3)ensuring tight cementation at the cement-sandstone interface and minimizing interfacial voids are paramount for preventing stress-induced failure;(4)the critical Von Mises stress value of 20 MPa at the interface defect can be used as a benchmark for material selection and designed to ensure long-term integrity in oil and gas well applications subjected to similar axial loads.These findings contribute to a more accurate understanding of the failure mechanism of the cement-sandstone interface and to the precise design of material properties,thereby ensuring the long-term integrity of oil and gas well applications subjected to similar axial loads.
基金Financial support from the National Natural Science Foundation of China(Grant No.52374119)the Province Education Department of Liaoning(Grant No.LJ212410146068)the opening fund of State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University(Grant No.HJGZ2023103).
文摘Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic behaviors of these combinations,especially the mechanism of action of prestressed bolts,still need to be further investigated.This study carried out split Hopkinson pressure bar(SHPB)tests on three sets of coal-rock(CR),CRB,and coal-rock-prestressed bolt(CRPB)combinations with different interface angles(β=15°,30°,45°,and 60°).The dynamic properties of the combinations were analyzed based on the stress-strain curve,energy dissipation,dynamic strength,fractal dimension of cracks,and failure mode of bolts.The test results show that a larger β will affect the stress transfer and anti-sliding ability of CR,resulting in a decrease in CR strength.The anchoring force of the bolt effectively suppresses the slip feature of CRB at the yield stage.As the strain rate increases,CRB shows a more pronounced'sudden increase'in strength,and the bolt significantly enhances its dynamic strength.The prestressed bolts enhance the dynamic strength of CRPB while weaken the effect of β.The fractal dimension of the macrocracks increases with strain rate,with smaller variations in CRB and CRPB,indicating that the bolt reduces the complexity degree of CRB and CRPB.The anchoring force of CRB depends on bolt strength,which reduces the slip along the interface.The anchoring force of CRPB balances the coal-rock slip and suppresses crack formation,resulting in a more cohesive response under dynamic load.
基金supported by the Shaanxi Qinchuang Yuan“scientist+engineer”team construction(No.2023KXJ-080)Shaanxi Chiral Drug Engineering Technology Research Center(Department of Science and Technology of Shaanxi Province.No.[2011]-251).
文摘Background:Human skin is affected by ultraviolet rays on a daily basis,and excessive ultraviolet radiation(UVR)can lead to sunburn erythema,tanning,photoaging,and skin tumors.The combination of Astragali Radix(AR)and Anemarrhenae Rhizoma(AAR)is a common pairing in traditional Chinese medicine(TCM).According to earlier studies,they possess properties capable of alleviating the adverse impacts of UVR on the skin.However,the specific actions and underlying mechanisms require further investigation.The study aims to analyze the efficacy of AR-AAR in preventing UVR-induced skin damage and to clarify the associated molecular mechanisms.Methods:Potential signaling pathways by which AR and AAR may protect against UVR-induced skin damage were identified with network pharmacology,molecular docking techniques and molecular dynamics(MD)simulation.Except the normal group,the back skin of SD rats was exposed to 1.1 mW/cm^(2) UVA combined with 0.1 mW/cm^(2) UVB daily,and the UVR skin damage model was established.Morphological features of skin tissues of different groups were discovered through Hematoxylin and Eosin(HE)staining,Masson staining,Weigert staining.ELISA was utilized to measure the levels of reactive oxygen species(ROS),Interleukin 6(IL-6),Interleukin 1β(IL-1β)and Tumor necrosis factos-α(TNF-α)in skin tissues.RT-PCR and Western blot were employed to quantify the mRNA and protein contents of PI3K,AKT,and MMP-9.Results:Network pharmacology analysis predicts that AR-AAR may improve skin damage induced by UVR through the PI3K/AKT signaling pathway.Histological staining shows that AR-AAR can significantly reduce inflammatory infiltration and fibrosis in damaged skin.Treatment with AR-AAR(2:1)significantly reduced the expression levels of IL-1β,IL-6,TNF-αand ROS in UVR-damaged rat skin.After treatment with AR-AAR(2:1),not only did the relative mRNA expression levels of PI3K and AKT and the protein expression levels of PI3K,AKT,P-PI3K,and P-AKT increase,but the mRNA and protein expression levels of MMP-9 decreased.Conclusion:The study indicate that the AR-AAR combination and its active components may mitigate UVR skin damage by modulating the PI3K/AKT signaling pathway.
基金supported by National Science and Technology Council(NSTC)Taiwan,Grant No.NSTC 113-2221-E-167-023.
文摘Mango is a plant with high economic value in the agricultural industry;thus,it is necessary to maximize the productivity performance of the mango plant,which can be done by implementing artificial intelligence.In this study,a lightweight object detection model will be developed that can detect mango plant conditions based on disease potential,so that it becomes an early detection warning system that has an impact on increasing agricultural productivity.The proposed lightweight model integrates YOLOv7-Tiny and the proposed modules,namely the C2S module.The C2S module consists of three sub-modules such as the convolutional block attention module(CBAM),the coordinate attention(CA)module,and the squeeze-and-excitation(SE)module.The dataset is constructed by eight classes,including seven classes of disease conditions and one class of health conditions.The experimental result shows that the proposed lightweight model has the optimal results,which increase by 13.15% of mAP50 compared to the original model YOLOv7-Tiny.While the mAP50:95 also achieved the highest results compared to other models,including YOLOv3-Tiny,YOLOv4-Tiny,YOLOv5,and YOLOv7-Tiny.The advantage of the proposed lightweightmodel is the adaptability that supports it in constrained environments,such as edge computing systems.This proposedmodel can support a robust,precise,and convenient precision agriculture system for the user.
文摘The internal flow fields within a three-dimensional inward-tunning combined inlet are extremely complex,especially during the engine mode transition,where the tunnel changes may impact the flow fields significantly.To develop an efficient flow field reconstruction model for this,we present an Improved Conditional Denoising Diffusion Generative Adversarial Network(ICDDGAN),which integrates Conditional Denoising Diffusion Probabilistic Models(CDDPMs)with Style GAN,and introduce a reconstruction discrimination mechanism and dynamic loss weight learning strategy.We establish the Mach number flow field dataset by numerical simulation at various backpressures for the mode transition process from turbine mode to ejector ramjet mode at Mach number 2.5.The proposed ICDDGAN model,given only sparse parameter information,can rapidly generate high-quality Mach number flow fields without a large number of samples for training.The results show that ICDDGAN is superior to CDDGAN in terms of training convergence and stability.Moreover,the interpolation and extrapolation test results during backpressure conditions show that ICDDGAN can accurately and quickly reconstruct Mach number fields at various tunnel slice shapes,with a Structural Similarity Index Measure(SSIM)of over 0.96 and a Mean-Square Error(MSE)of 0.035%to actual flow fields,reducing time costs by 7-8 orders of magnitude compared to Computational Fluid Dynamics(CFD)calculations.This can provide an efficient means for rapid computation of complex flow fields.
基金Supported by “The 12th five-year plan” programmed project of educational science in Hubei Province:2014B095
文摘Objective To observe the influence of different acupoint combinations on immediate effect of surface electromyography of patients with cervical spondylosis, and to explore the interactions and laws among different acupoint combinations. Methods Acupuncture in three kinds of different acupoint combinations was conducted on 90 patients with cervical spondylosis（three groups）： group A [distal point selection group： Kūnlún（昆仑 BL 60） and Hòuxī（后溪 SI 3）]; group B [local point selection group： Fēngchí（风池 GB 20） and Tiānzhù（天柱 BL 10）]; group C（distal and local point selection group： BL 60, SI 3, GB 20 and BL 10）. Self control before and after treatment was adopted to observe the mean value of surface electromyography（SEMG） amplitude, to measure the mean values of integrated electromyography（IEMG） and electromyography root mean square（RMS）, and to calculate the variation rate of electromyography amplitude of trapezius on the affected side of patients before and after acupuncture. The differences of influences of different acupoint combinations on immediate effect of surface electromyography were compared intra-group, and the differences among the three groups after acupuncture were also compared. Results According to the intragroup comparison before and after acupuncture, the differences of mean value of electromyography amplitude, variation rate of electromyography amplitude, IEMG and RMS were both statistically significant（all P〈0.05）. According to the inter-group comparison after acupuncture, the mean value of electromyography amplitude, variation rate of electromyography amplitude, IEMG and RMS varied in different degrees, however, the differences were not significant（all P〉0.05）; there was no significant difference in the total effective rate among the three groups（P〉0.05）. Conclusion Acupuncture treatment in different acupoint combinations can increase IEMG and RMS and reduce mean value of electromyography amplitude and variation rate of electromyography amplitude, enhance cervical vertebral stability and active contractility of muscle fiber, and improve the fatigue resistance of neck flexion; while, the therapeutic effect of acupuncture on cervical spondylosis has nothing to do with the distance or the number of selected acupoint.
基金Supported by Financial Genetic Engineering Program of Sichuan Province during the 12th Five-Year Plan Period(2011JYGC11-029)Sichuan Innovation Team Program of National Modern Agricultural Industry Technology System of China+1 种基金Rice Breeding Program of Sichuan Province during the 12th Five-Year Plan Period(2011NZ-0098-1)Major Scientific and Technological Project of Luzhou City(2011-N-09)~~
文摘During 2000-2013, totally ten high-amylose specific hybrid rice combinations approved and five combinations for production test were bred in Sichuan Province. In the paper, rice yield, economic traits, quality indicators and rice blast-resistance identification results of these 15 hybrid combinations were described and analyzed. Results show that Chuanxiangyou37 and Tianlongyou540 have relatively high amylose content, good yielding ability, high resistance and appropriate growth period, which are new hybrid rice varieties with organic combination of high amylase content, high gel consistency, high yield, stable yield and wide adaptability. Therefore, Chuanxiangyou37 and Tianlongyou540 are recommended as the main combination for rice production.
基金supported by grants from the National Natural Science Foundation of China (No. 81171986)the Ministry of Public Health (No. 201501004)
文摘Programmed cell death 1（PD-1）/programmed cell death 1 ligand（PD-L1） blockade has shown promising effects in cancer immunotherapy. Removing the so-called ＂brakes＂ on T cell immune responses by blocking the PD-1/PDL1 check point should boost anti-tumor immunity and provide durable tumor regression for cancer patients.However, 30%–60% of patients show no response to PD-1/PD-L1 blockade. Thus, it is urgent to explore the underlying resistance mechanisms to improve sensitivity to anti-PD-1/PD-L1 therapy. We propose that the mechanisms promoting resistance mainly include T cell exclusion or exhaustion at the tumor site,immunosuppressive factors in the tumor microenvironment（TME）, and a range of tumor-intrinsic factors. This review highlights the power of studying the cellular and molecular mechanisms of resistance to improve the rational design of combination therapeutic strategies that can be translated to the clinic. Here, we briefly discuss the development of PD-1/PD-L1 blockade agents and focus on the current issues and future prospects for potential combinatorial therapeutic strategies that include anti-PD-1/PD-L1 therapy, based upon the available preclinical and clinical data.
基金Project(2014QNB31)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(51674248)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock combinations. Fifty-four coal–rock combinations were prepared and split equally into groups containing different moisture contents(dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal–rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal–rock combinations and laws of crack propagation.
基金Supported by the Hubei Normal University Research Grant (2008D54)
文摘The invertibility of combinations of two orthogonal projectors aP ＋ bQ - cPQ - dQP is researched by using the CSdecomposition of matrices and properties of orthogonal projectors. The Moore-enrose inverse of the combinations is presented under some special conditions.
基金Supported by the Key Academic Discipline of Zhejiang Provincial of China under Grant No.2005.
文摘In this paper we give equivalent theorems on simultaneous approximation for the combinations of Bernstein operators by r-th Ditzian- Totik modulus of smoothness w^rφλ （f, t）（0 ≤ λ≤ 1）. We also investigate the relation between the derivatives of the combinations of Bernstein operators and the smoothness of derivatives of functions.
文摘There have been exponential gains in immuno-oncology in recent times through the development of immune checkpoint inhibitors. Already approved by the U.S. Food and Drug Administration for advanced melanoma and non-small cell lung cancer,immune checkpoint inhibitors also appears to have significant antitumor activity in multiple other tumor types. An exciting component of immunotherapy is the durability of antitumor responses observed, with some patients achieving disease control for many years. Nevertheless, not all patients benefit, and efforts should thus now focus on improving the efficacy of immunotherapy through the use of combination approaches and predictive biomarkers of response and resistance. There are multiple potential rational combinations using an immunotherapy backbone, including existing treatments such as radiotherapy, chemotherapy or molecularly targeted agents, as well as other immunotherapeutics. The aim of such antitumor strategies will be to raise the tail on the survival curve by increasing the number of long term survivors, while managing any additive or synergistic toxicities that may arise with immunotherapy combinations. Rational trial designs based on a clear understanding of tumor biology and drug pharmacology remain paramount. This article reviews the biology underpinning immuno-oncology, discusses existing and novel immunotherapeutic combinations currently in development, the challenges of predictive biomarkers of response and resistance and the impact of immuno-oncology on early phase clinical trial design.
文摘The purpose of this paper is to characterize the pointwise rate of convergence for the combinations of Szász-Mirakjan operators using Ditzian-Totik modulus of smoothness.
基金supported by grants from Key ProgramNational Natural Science Foundation of China(81930016)+3 种基金National Natural Science Foundation of China(81702858)Key Research&Development Plan of Zhejiang Province(2019C03050)National S&T Major Project(2017ZX10203205)National Natural Science Funds for Distinguished Young Scholar of China(81625003)。
文摘Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechanism and therapeutic strategies have not been clarified.This study aimed to identify potential roles of mi RNA/m RNA axis in the pathogenesis and drug combinations in the treatment of NASH.Methods:Microarray GSE59045 and GSE48452 were downloaded from the Gene Expression Omnibus and analyzed using R.Then we obtained differentially expressed genes(DE-genes).DAVID database was used for Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment pathway analysis.Protein-protein interaction(PPI)networks were used for the identification of hub genes.We found upstream regulators of hub genes using mi RTar Base.The expression and correlation of key mi RNA and its targets were detected by q PCR.Drug Pair Seeker was employed to predict drug combinations against NASH.The expression of mi RNA and hub genes in HCC was identified in the Cancer Genome Atlas database and Human Protein Atlas database.Results:Ninety-four DE-genes were accessed.GO and KEGG analysis showed that these predicted genes were linked to lipid metabolism.Eleven genes were identified as hub genes in PPI networks,and they were highly expressed in cells with vigorous lipid metabolism.hsa-mi R-335-5 p was the upstream regulator of 9 genes in the 11 hub genes,and it was identified as a key mi RNA.The hub genes were highly expressed in NASH models,while hsa-mi R-335-5 p was lowly expressed.The correlation of mi RNA-m RNA was established by q PCR.Functional verification indicated that hsa-mi R-335-5 p had inhibitory effect on the development of NASH.Finally,drug combinations were predicted and the expression of mi RNA and hub genes in HCC was identified.Conclusions:In the study,potential mi RNA-m RNA pathways related to NASH were identified.Targeting these pathways may be novel strategies against NASH.
基金funded by National key Technology R & D Program (2008BADB2B02)
文摘[Objective] The aim of this study was to investigate the production performance of three pig cultivars through their fattening performance, carcass traits and meat quality for facilitating its application in practical production. [ Method] Three pig cultivars were selected including Yesong （ F1 hybrid of pure-bred wild boar cross with songliao black sow as female parent） hybrid pigs, D × L × Y pigs from three-way cross and L x Y pigs from two-way cross. The test pigs in early period （before 60 kg） and late period （after 60 kg） were all fed with diets of the same nutritional level by free feeding and drinking water. The pre-test period was 3 d, while the test period was 120 d. Every 30 days, pigs with an empty stomach were weighed on morning, and when fattening to 120 d, five pigs with good growth and development in each cultivar were selected for slaughter to determine carcass traits and meat quality. [ Result] Under the same diets and feeding conditions, average daily gain and weight gain in the whole period of pigs from three-way cross were all significantly higher than those of pigs from two-way cross, and also extremely higher than those of Yesong pigs. There was no difference in dressed carcass percentage, backfat thickness and proportion of hind leg among three hybrid combinations. Lean meat percentage and eye muscle area of pigs from three-way cross and pigs from two-way cross were all significantly higher than those of Yesong pigs. Yesong pigs had relatively darker carnation, but marble vein （P〈0.05） and water loss rate （P〈0. 01 ） of Yesong pigs were relatively fewer than those of pigs from two-way cross and pigs from three-way cross. Shear force of Yesong pigs was significantly higher than that of pigs from two-way cross and pigs from three-way cross, [ Conclusion] Yesong hybrid pigs make full use of heterosis between wild pigs and Songliao black pigs for improvement of its meat quality, but some values of major economic traits in Yesong hybrid pigs is still lower than those in pigs from thrae-way cross and pigs from two-way cress.
文摘In this paper, linear combinations of composition operators acting on weighted Dirichlet spaces are studied. By using the first derivative of the kernel function, we obtain a lower estimate for the essential norms of these operators acting on the Dirichlet space D and S2. For general weighted Dirichlet space, by using complex interpolation methods, we characterize the compactness of these operators induced by linear fractional self-maps of the disk.
基金Supported by the Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education, China(No.2006KDZ05).
文摘GPS positioning precision is affected by various error sources, and traditional combinations of GPS carrier phase observations have their own limitations such as the wide-lane, the narrow-lane and the ionospheric-free combinations. To obtain the optimal positioning precision, a new linear combination method is addressed through the variance-covariance （VCV） of the GPS multi-frequency carrier phase combination equations, and the impact of the positioning precision is analyzed with the changing of the observation errors deduced by the law of error propagation. For the high precision positioning with only one carrier phase combination, the optimal combination method is deduced and further validated by an example of a baseline resolution with 60 km length. The result indicates that this method is the simplest, and the positioning precision is the best. Therefore, it is useful for long baseline quick positioning for different precision requirements in various distances.
