The G?ksun(Kahramanmaras)ophiolite(GKO),cropping out in a tectonic window bounded by the Malatya metamorphic unit on both the north and south,is located in the EW-trending lower nappe zone of the southeast Anatolian o...The G?ksun(Kahramanmaras)ophiolite(GKO),cropping out in a tectonic window bounded by the Malatya metamorphic unit on both the north and south,is located in the EW-trending lower nappe zone of the southeast Anatolian orogenic belt(Turkey).It exhibits a complete oceanic lithospheric section and overlies the Middle Eocene Maden Group/Complex with a tectonic contact at its base.The ophiolitic rocks and the tectonically overlying Malatya metamorphic(continental)unit were intruded by I-type calc-alkaline Late Cretaceous granitoid(~81-84 Ma).The ultramafic to cumulates in the GKO are represented by wehrlite,plagioclase wehrlite,olivine gabbro and gabbro.The crystallization order for the cumulate rocks is as follows:olivine±chromian spinel→clinopyroxene→plagioclase.The major and trace element geochemistry as well as the mineral chemistry of the ultramafic to mafic cumulate rocks suggest that the primary magma generating the GKO is compositionally similar to that observed in the modern island-arc tholeiitic sequences.The mineral chemistry of the ultramafic to mafic cumulates indicates that they were derived from a mantle source that was previously depleted by earlier partial melting events.The highly magnesian olivine(Fo77-83),clinopyroxene(Mg#of 82-90)and the highly Ca-plagioclase(An81-89)exhibit a close similarity to those,which formed in a supra-subduction zone(SSZ)setting.The field and the geochemical evidence suggest that the GKO formed as part of a much larger sheet of oceanic lithosphere,which accreted to the base of the Tauride active continental margin,including the ispendere,K?mürhan and the Guleman ophiolites.The latter were contemporaneous and genetically/tectonically related within the same SSZ setting during the closure of the Neotethyan oceanic basin(Berit Ocean)between the Taurides to the north and the Bitlis-Pütürge massif to the south during the Late Cretaceous.展开更多
Due to their high density,the ilmenite-bearing cumulates(IBC)(with or without KREEP)formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar ...Due to their high density,the ilmenite-bearing cumulates(IBC)(with or without KREEP)formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle overturn.Geophysical evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary(CMB).However,partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant,thus preventing the IBC/KREEP layer from sinking to the CMB.Here,we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO model.The modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt%partial melting in the shallow(~120 km)and a much larger degree of partial melting in the deep lunar mantle(~420 km).Due to the density contrast with the surrounding mantle,IBC/KREEP-bearing melts could potentially decouple under certain conditions.The modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma ocean.Sinking of IBC/KREEP back into the lunar mantle may introduce plagioclase,clinopyroxene,garnet,and incompatible radioactive elements into the deep lunar mantle,which will further affect the thermal and chemical evolution of the lunar interior.展开更多
Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental man...Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental mantle evolution（partial melting and metasomatism in upper mantle）.Until now,varieties of sulfide inclusions have been extensively discovered in the ultramafic or mafic phenocrysts.展开更多
The Late Cretaceous Sabzevar ophiolite represents one of the largest and most complete fragments of Tethyan oceanic lithosphere in the NE Iran.It is mainly composed of serpentinized mantle peridotites slices;nonethele...The Late Cretaceous Sabzevar ophiolite represents one of the largest and most complete fragments of Tethyan oceanic lithosphere in the NE Iran.It is mainly composed of serpentinized mantle peridotites slices;nonetheless,minor tectonic slices of all crustal sequence constituents are observed in this ophiolite.The crustal sequence contains a well-developed ultramafic and mafic cumulates section,comprising plagioclase-bearing wehrlite,olivine clinopyroxenite,olivine gabbronorite,gabbronorite,amphibole gabbronorite and quartz gabbronorite with adcumulate,mesocumulate,heteradcumulate and orthocumulate textures.The crystallization order for these rocks is olivine±chromian spinel→clinopyroxene→plagioclase→orthopyroxene→amphibole.The presence of primary magmatic amphiboles in the cumulate rocks shows that the parent magma evolved under hydrous conditions.Geochemically,the studied rock units are characterized by low TiO2(0.18-0.57 wt.%),P2 O5(<0.05 wt.%),K2 O(0.01-0.51 wt.%)and total alkali contents(0.12-3.04 wt.%).They indicate fractionated trends in the chondrite-normalized rare earth element(REE)plots and multi-element diagrams(spider diagrams).The general trend of the spider diagrams exhibit slight enrichment in large ion lithophile elements(LILEs)relative to high field strength elements(HFSEs)and positive anomalies in Sr,Pb and Eu and negative anomalies in Zr and Nb relative to the adjacent elements.The REE plots of these rocks display increasing trend from La to Sm,positive Eu anomaly(Eu/Eu*=1.06-1.54)and an almost flat pattern from medium REE(MREE)to heavy REE(HREE)region[(Gd/Yb)N=1-1.17].Moreover,clinopyroxenes from the cumulate rocks have low REE contents and show marked depletion in light REE(LREE)compared to MREE and HREE[(La/Sm)N=0.10-0.27 and(La/Yb)N=0.08-0.22].The composition of calculated melts in equilibrium with the clinopyroxenes from less evolved cumulate samples are closely similar to island arc tholeiitic(IAT)magmas.Modal mineralogy,geochemical features and REE modeling indicate that Sabzevar cumulate rocks were formed by crystal accumulation from a hydrous depleted basaltic melt with IAT affinity.This melt has been produced by moderate to high degree(~15%)of partial melting a depleted mantle source,which partially underwent metasomatic enrichment from subducted slab components in an intra-oceanic arc setting.展开更多
Mafic enclaves in granites are generally considered to represent coeval mafic melts that derived from metasomatized mantle,which can provide valuable information about crust-mantle interaction.Exploring the genetic li...Mafic enclaves in granites are generally considered to represent coeval mafic melts that derived from metasomatized mantle,which can provide valuable information about crust-mantle interaction.Exploring the genetic links between the mafic enclaves and their host monzogranite from the Triassic Zhashui Pluton,Qinling orogenic belt.The enclaves(220±4.6 Ma)and the monzogranite(220±2.8 Ma)display identical zircon U-Pb ages,and they also share similar trace element and zircon Lu-Hf isotopes,indicating a cognate source.The monzogranite displays zirconεHf(t)values of−0.99 to+1.98,while the mafic enclaves show similar values of−0.45 to+3.26;however,differences in mineral chemistry reveal different crystallization conditions.The amphibole from the mafic enclaves has higher temperature and pressure(757℃;2.65 kbar)compared to those of the host monzogranite(733℃;1.96 kbar),suggesting that mafic minerals in the enclaves crystallized at an early stage.Moreover,apatite in the mafic enclaves displays slightly higher volatile contents(0.72 wt%)than those of the monzogranite(0.66 wt%),indicating a volatile-rich condition.These results suggest that the mafic enclaves represent early hydrous mafic cumulates in the granitic chamber,and subsequent magma convection would have led to the formation of the mafic enclaves.展开更多
The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triass...The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triassic cumulate hornblende gabbro was identified in the southern margin of the Gangdese magmatic belt.The gabbro exhibits cumulate structure,with hornblende and plagioclase as the primary mineral phases.Isotopic data indicate a hydrous magma source derived from a depleted mantle wedge that has been modified by slab dehydration.Geochemical discriminations suggest that the gabbro was formed in an intraoceanic arc setting,with crystallization ages of ca.220-213 Ma.Hornblende,hornblendelagioclase and ilmenite thermometers reveal that the crystallization temperature of 900-750°C for the gabbro.Hornblende and hornblende-plagioclase geobarometers yield an emplacement depth at ca.14.5-19.5 km.This gabbro constitutes a line of evidence for an intraoceanic arc magmatism that is coeval with the counterparts in the southern Turkey,revealing an intraoceanic subduction system within the Neotethys from west to east in the Late Triassic and that the oceanization of the Neotethys was much earlier than previous expectation.展开更多
Cyclic impact induces ongoing fatigue damage and performance degradation in anchoring structures,ser-ving as a critical factor leading to the instability of deep roadways.This paper takes the intrinsic spatio-temporal...Cyclic impact induces ongoing fatigue damage and performance degradation in anchoring structures,ser-ving as a critical factor leading to the instability of deep roadways.This paper takes the intrinsic spatio-temporal relationship of macro-microscopic cumulative damage in anchoring structures as the main thread,revealing the mechanism of bearing capacity degradation and progressive instability of anchoring structure under cyclic impact.Firstly,a set of impact test devices and methods for the prestressed solid anchor bolt anchoring structure were developed,effectively replicating the cyclic impact stress paths in situ.Secondly,cyclic impact anchoring structure tests and simulations were conducted,which clarifies the damage evolution mechanism of the anchoring structure.Prestress loss follows a cubic decay func-tion as the number of impacts increases.Under the same impact energy and pretension force,the impact resistance cycles of extended anchoring and full-length anchoring were increased by 186.7%and 280%,respectively,compared to end anchoring.The rate of internal damage accumulation is positively corre-lated with impact energy and negatively correlated with anchorage length.Internal tensile cracks account for approximately 85%.Stress transmission follows a fluctuating pattern.Compared to the extended anchoring,the maximum vibration velocity of the exposed end particles in the full-length anchoring was reduced by 59.31%.Damage evolution exhibits a pronounced cumulative mutation effect.Then,a three-media,two-interface mechanical model of the anchoring structure was constructed.It has been clarified that the compressive stress,tensile stress,and oscillation effect arising from rapid transi-tions between compression and tension are the primary internal factors responsible for the degradation of the anchoring structure’s bearing capacity.Finally,the progressive instability mechanism of the anchoring structure under cyclic impact was elucidated.The mutual feedback and superposition of media rupture,interface debonding,and bearing capacity degradation result in overall failure.The failure pro-cess involves stages dominated by oscillation-compression,tensile stress,and compression failure.A tar-geted control strategy was further proposed.This provides a reference for maintaining the long-term stability of deep roadways under dynamic impact loads.展开更多
Metabasites consisting of metamorphic ultra-mafic rocks, cumulate gabbro, gabbro (diabase), basalt, and plagiogranite are exposed at the Taoxinghu area in central Qiangtang, northern Tibetan Plateau. Zircon SHRIMP U-P...Metabasites consisting of metamorphic ultra-mafic rocks, cumulate gabbro, gabbro (diabase), basalt, and plagiogranite are exposed at the Taoxinghu area in central Qiangtang, northern Tibetan Plateau. Zircon SHRIMP U-Pb dating for the cumulate gabbro yields a weighted mean age of 467±4 Ma, which is the oldest and most reliable magmatic age in this area. Zircon 176Hf/177Hf ratios range from 0.282615 to 0.282657, with εHf(t) values of 5.02±0.28, indicating that the cumulate gabbro was mainly derived from the depleted mantle. In addition, geochemical data of metabasites suggest that they have similar characteristics to those in the mid-ocean ridge basalts (MORB). The Taoxinghu metabasites may represent the fragment of Early Paleozoic ophiolite in the "Central Uplift" of the Qiangtang, northern Tibetan Plateau.展开更多
Mafic xenoliths occur in Mesozoic diorites from nine localities in eastern Inner Mongolia from the Da Hinggan Mrs. to Huabei craton. Their petrologic and geochemical features suggest that they are an intact suite of c...Mafic xenoliths occur in Mesozoic diorites from nine localities in eastern Inner Mongolia from the Da Hinggan Mrs. to Huabei craton. Their petrologic and geochemical features suggest that they are an intact suite of cumulate complex whose mineral assemblages contain typical patent mantle metasomatism minerals such as pargosite, phlogopite and apatite. Their REEs and trace element characteristics suggest a comagmatic relationship in these cumulates with different compositions. Isotopic dating of the xenoliths indicates that they are products of the mantle magmatic underplating in the Early Mesozoic (237—224 Ma), and they may provide direct evidence for the crust-mantle interaction and vertical accretion of continental crust under a background of the mantle upwelling in the Early Mesozoic in Huabei region.展开更多
BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity va...BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity variables affect MDD.We hypothesize that high-level trait-and state-related stress-sensitivity factors may have different cumulative effects on the clinical symptoms and follow-up outcomes of MDD.AIM To investigate how stress-sensitivity factors added up and affected MDD clinical symptoms and follow-up results.METHODS In this prospective study,281 MDD patients were enrolled from a tertiary care setting.High-level stress-sensitivity factors were classified as trait anxiety,state anxiety,perceived stress,and neuroticism,with a total score in the top quartile of the research cohort.The cumulative effects of stress-sensitivity factors on cognitive dysfunction,disability and functional impairment,suicide risk,and depressive and anxiety symptoms were examined using an analysis of variance with linear trend analysis.Correlations were investigated further using multiple regression analysis.RESULTS Regarding high-level stress-sensitivity factors,53.40%of patients had at least one at baseline,and 29.61%had two or more.Four high-level stress-sensitivity components had significant cumulative impacts on MDD symptoms at baseline(all P<0.001).Perceived stress predicted the greatest effect sizes of state-related factors on depressive symptoms(partialη^(2)=0.153;standardizedβ=0.195;P<0.05).The follow-up outcomes were significantly impacted only by the high-level trait-related components,mainly when it came to depressive symptoms and suicide risk,which were predicted by trait anxiety and neuroticism,respectively(partialη^(2)=0.204 and 0.156;standardizedβ=0.247 and 0.392;P<0.05).CONCLUSION To enhance outcomes of MDD and lower the suicide risk,screening for stress-sensitivity factors and considering multifaceted measures,mainly focusing on trait-related ones,should be addressed clinically.展开更多
Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections h...Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections have the form ∝ L^(-ω),then we find ω=1.546(30) andω=1.509(14) as the best estimates.These are obtained from the finite-size scaling of the susceptibility data in the range of linear lattice sizes L ∈[128,2048] at the critical value of the Binder cumulant and from the scaling of the corresponding pseudocritical couplings within L∈[64,2048].These values agree with several other MC estimates at the assumption of the power-law corrections and are comparable with the known results of the ε-expansion.In addition,we have tested the consistency with the scaling corrections of the form ∝ L^(-4/3),∝L^(-4/3)In L and ∝L^(-4/3)/ln L,which might be expected from some considerations of the renormalization group and Coulomb gas model.The latter option is consistent with our MC data.Our MC results served as a basis for a critical reconsideration of some earlier theoretical conjectures and scaling assumptions.In particular,we have corrected and refined our previous analysis by grouping Feynman diagrams.The renewed analysis gives ω≈4-d-2η as some approximation for spatial dimensions d <4,or ω≈1.5 in two dimensions.展开更多
Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves a...Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.展开更多
BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS...BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS.However,the optimal timing for polyp screening and preventive intervention using entero-scopic polypectomy remains uncertain.This is primarily due to the extremely low incidence of the condition and the paucity of data regarding the natural risk of requiring surgery and its age distribution in PJS patients.In order to develop recommendations on the appropriate timing of polyp screening and preventive intervention in PJS,a comprehensive understanding of the natural surgical risks AIM To investigate the natural surgical risks associated with polyps in PJS and to clarify their age distribution.METHODS A web-based open survey was launched to collect information from Chinese individuals suspected of having PJS.The questionnaire was distributed to the PJS instant messaging groups using a quick response code method.The data were analyzed using descriptive statistical methods,and the cumulative incidence of surgery was calculated using the Kaplan-Meier method.RESULTS Of the 442 patients enrolled,301(68.10%)had undergone 506 surgical procedures prior to enteroscopy or the survey deadline.Among the 506 surgical procedures,388(76.68%)were performed on patients aged between 6 and 25 years.The cumulative incidence rates of the first surgical procedure at 5,10,15,20,25,and 30 years of age were 5.0%(95%confidence interval[CI]:2.9%-7.0%),20.6%(95%CI:16.6%-24.4%),40.5%(95%CI:35.5%-45.1%),58.0%(95%CI:52.7%-62.7%),72.6%(95%CI:67.3%-77.0%),and 82.4%(95%CI:77.0%-86.5%),respectively.The primary indications for the first surgical procedures were intussusception(81.40%),obstruction(13.95%),and gas-trointestinal bleeding(4.65%).The cumulative incidence rates of requiring a second surgical procedure within 1,3,5,10 and 15 years following the first surgical procedure were 3.7%(95%CI:1.5%-5.8%),12.5%(95%CI:8.6%-16.2%),20.3%(95%CI:15.6%-24.8%),37.0%(95%CI:33.1%-45.3%),54.2%(95%CI:46.8%-60.5%),respectively.Patients who underwent their first surgical procedure at the age of nine years or younger presented an elevated risk of requiring a second surgical procedure(P<0.01).CONCLUSION Chinese patients with PJS have a high natural risk of undergoing surgery.Without preventive intervention,these procedures may become necessary at an early age and may be repeated.Early screening and regular surveillance,with preventive intervention if necessary,should commence at six years of age.展开更多
Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purp...Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purpose of this study was to systematically alter the trunk lean angle in distance running using an auditory real-time feedback approach and to derive dose-response relationships between sagittal plane trunk lean angle and lower extremity(cumulative)joint loading to guide overuse load management in clinical practice.Methods:Thirty recreational runners(15 males and 15 females)ran at a constant speed of 2.5 m/s at 5 systematically varied trunk lean conditions on a force-instrumented treadmill while kinematic and kinetic data were captured.Results:A change in trunk lean angle from-2°(extension)to 28°(flexion)resulted in a systematic increase in stance phase angular impulse,cumulative impulse,and peak moment at the hip joint in the sagittal and transversal plane.In contrast,a systematic decrease in these parameters at the knee j oint in the sagittal plane and the hip joint in the frontal plane was found(p<0.001).Linear fitting revealed that with every degree of anterior trunk leaning,the cumulative hip joint extension loading increases by 3.26 Nm·s/kg/1000 m,while simultaneously decreasing knee joint extension loading by 1.08 Nm·s/kg/1000 m.Conclusion:Trunk leaning can reduce knee joint loading and hip joint abduction loading,at the cost of hip joint loading in the sagittal and transversal planes during distance running.Modulating lower extremity joint loading by altering trunk lean angle is an effective strategy to redistribute joint load between/within the knee and hip joints.When implementing anterior trunk leaning in clinical practice,the increased demands on the hip musculature,dynamic stability,and the potential trade-off with running economy should be considered.展开更多
As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wi...As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wind speed correlation,a multi-scenario PLF calculation method that combines random sampling and segmented discrete wind farm power was proposed.Firstly,based on constructing discrete scenes of wind farms,the Nataf transform is used to handle the correlation between wind speeds.Then,the random sampling method determines the output probability of discrete wind power scenarios when wind speed exhibits correlation.Finally,the PLF calculation results of each scenario areweighted and superimposed following the total probability formula to obtain the final power flow calculation result.Verified in the IEEE standard node system,the absolute percent error(APE)for the mean and standard deviation(SD)of the node voltages and branch active power are all within 1%,and the average root mean square(AMSR)values of the probability curves are all less than 1%.展开更多
In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion...In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion-resistant and cost-effective.However,the damage mechanisms of GFRP bolts under blasting dynamic loads are still unclear,especially compared to metal bolts.This study investigates the cumulative damage of fully grouted GFRP bolts under blasting dynamic loads.The maximum axial stress at the tails of the bolts is defined as the damage variable,based on the failure characteristics of GFRP bolts.By combining this with Miner's cumulative damage theory,a comprehensive theoretical and numerical model is established to calculate cumulative damage.Field data collected from the Jinchuan No.3 Mining Area,including GFRP bolts parameters and blasting vibration data are used for further analysis of cumulative damage in fully grouted GFRP bolts.Results indicate that with an increasing number of blasts,axial stress increases in all parts of GFRP bolts.The tail exhibits the most significant rise,with stress extending deeper into the anchorage zone.Cumulative damage follows an exponential trend with the number of blasts,although the incremental damage per blast decelerates over time.Higher dynamic load intensities accelerate damage accumulation,leading to an exponential decline in the maximum loading cycles before failure.Additionally,stronger surrounding rock and grout mitigate damage accumulation,with the effect of surrounding rock strength being more pronounced than that of grout.In contrast,the maximum axial stress of metal bolts increases quickly to a certain point and then stabilizes.This shows a clear difference between GFRP and metal bolts.This study presents a new cumulative damage theory that underpins the design of GFRP bolt support systems under blasting conditions,identifies key damage factors,and suggests mitigation measures to enhance system stability.展开更多
Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occu...Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occurrence of pressure injuries(PIs).Methods:In this retrospective longitudinal study,we obtained health-related data from the Medical Information Mart for Intensive Care IV database,including sociodemographic,disease-related variables,and ICU treatment variables.The daily CFB adjusted for body weight was calculated,and the occurrence of PIs during the ICU stay was recorded.A group-based trajectory model was used to explore the different CFB trajectories.Binary logistic regression was used to analyze the relationship between the CFB trajectory group and PIs.Results:Among the 4,294 included participants,we identified four distinct trajectories of CFB in ICU patients:the rapid accumulation group(12.5%),the slow accumulation group(28.5%),the neutral balance group(41.7%),and the negative decrease group(17.3%).After adjusting for some sociodemographic,disease-related variables,and ICU treatment variables,the rapid accumulation group had an OR of 1.63(95%CI:1.30,2.04)for all stages of PIs and an OR of 1.36(95%CI:1.08,1.72)for stage II or higher PIs compared to the neutral balance group.Conclusions:Four unique trajectories of CFB were identified among patients in the ICU,including rapid accumulation,slow accumulation,neutral balance,and negative decrease.Rapid accumulation independently increased the risk of PIs during ICU stay.展开更多
In November 2024,the Global Solar Council announced that the world cumulative solar capacity reached 2 terawatts,twice as much as in mid-2022,clearly showing that solar energy is set to lead the energy transition.
Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-in...Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.展开更多
On 18 December 2023,a MS 6.2 earthquake struck the Jishishan area in Northwest China,located at the border of the Qinghai-Tibet and Loess Plateau.The earthquake triggered shallow loess landslides,small rock failures,a...On 18 December 2023,a MS 6.2 earthquake struck the Jishishan area in Northwest China,located at the border of the Qinghai-Tibet and Loess Plateau.The earthquake triggered shallow loess landslides,small rock failures,and soil cracks,mainly along hilly gullies and cut slopes at the edges of terraced fields.A rare large-scale flowslide also occurred in irrigated farmland.These seismic landslides and collapses blocked roads,buried farmland,damaged houses,and resulted in many casualties.Field investigations revealed that these geological hazards were concentrated around cultivated land.Consequently,cultivated land was introduced as an engineering geological zoning factor into the seismic geological hazard risk assessment for Jishishan area.The Newmark cumulative displacement model was refined by incorporating lithological uncertainties via the Monte Carlo method.Comparative analysis of coseismic geohazards with and without considering cultivated land suggests that,in loess-covered areas with cultivation activities,the consideration of the disturbed characteristics of soils provides a more accurate probabilistic risk assessment of seismic geohazards.Human cultivation and irrigation activities affect the physical properties of surface soil,the terraced fields around earthquake prone areas have a risk of earthquake-induced geological hazards.This study may offer valuable insights for hazard prevention and mitigation in high fortification intensity loess covered areas.展开更多
基金supported by TüBITAK (YDABCAG199Y011) and the Cukurova University Scientific Research Projects (MMF2002BAP41)the Open Fund (GPMR201702) of State Key Lab of Geological Processes and Mineral Resources,China University of Geosciences,Wuhansubsidy by the Russian Government to support the Program of competitive growth of Kazan Federal University
文摘The G?ksun(Kahramanmaras)ophiolite(GKO),cropping out in a tectonic window bounded by the Malatya metamorphic unit on both the north and south,is located in the EW-trending lower nappe zone of the southeast Anatolian orogenic belt(Turkey).It exhibits a complete oceanic lithospheric section and overlies the Middle Eocene Maden Group/Complex with a tectonic contact at its base.The ophiolitic rocks and the tectonically overlying Malatya metamorphic(continental)unit were intruded by I-type calc-alkaline Late Cretaceous granitoid(~81-84 Ma).The ultramafic to cumulates in the GKO are represented by wehrlite,plagioclase wehrlite,olivine gabbro and gabbro.The crystallization order for the cumulate rocks is as follows:olivine±chromian spinel→clinopyroxene→plagioclase.The major and trace element geochemistry as well as the mineral chemistry of the ultramafic to mafic cumulate rocks suggest that the primary magma generating the GKO is compositionally similar to that observed in the modern island-arc tholeiitic sequences.The mineral chemistry of the ultramafic to mafic cumulates indicates that they were derived from a mantle source that was previously depleted by earlier partial melting events.The highly magnesian olivine(Fo77-83),clinopyroxene(Mg#of 82-90)and the highly Ca-plagioclase(An81-89)exhibit a close similarity to those,which formed in a supra-subduction zone(SSZ)setting.The field and the geochemical evidence suggest that the GKO formed as part of a much larger sheet of oceanic lithosphere,which accreted to the base of the Tauride active continental margin,including the ispendere,K?mürhan and the Guleman ophiolites.The latter were contemporaneous and genetically/tectonically related within the same SSZ setting during the closure of the Neotethyan oceanic basin(Berit Ocean)between the Taurides to the north and the Bitlis-Pütürge massif to the south during the Late Cretaceous.
基金funded by the National Natural Science Foundation of China(41773052,41973058)。
文摘Due to their high density,the ilmenite-bearing cumulates(IBC)(with or without KREEP)formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle overturn.Geophysical evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary(CMB).However,partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant,thus preventing the IBC/KREEP layer from sinking to the CMB.Here,we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO model.The modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt%partial melting in the shallow(~120 km)and a much larger degree of partial melting in the deep lunar mantle(~420 km).Due to the density contrast with the surrounding mantle,IBC/KREEP-bearing melts could potentially decouple under certain conditions.The modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma ocean.Sinking of IBC/KREEP back into the lunar mantle may introduce plagioclase,clinopyroxene,garnet,and incompatible radioactive elements into the deep lunar mantle,which will further affect the thermal and chemical evolution of the lunar interior.
基金financially supported by the National Natural Science Foundation of China(grant No. 41302062)the China Geological Survey(grant No. 12120115034401)
文摘Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental mantle evolution（partial melting and metasomatism in upper mantle）.Until now,varieties of sulfide inclusions have been extensively discovered in the ultramafic or mafic phenocrysts.
文摘The Late Cretaceous Sabzevar ophiolite represents one of the largest and most complete fragments of Tethyan oceanic lithosphere in the NE Iran.It is mainly composed of serpentinized mantle peridotites slices;nonetheless,minor tectonic slices of all crustal sequence constituents are observed in this ophiolite.The crustal sequence contains a well-developed ultramafic and mafic cumulates section,comprising plagioclase-bearing wehrlite,olivine clinopyroxenite,olivine gabbronorite,gabbronorite,amphibole gabbronorite and quartz gabbronorite with adcumulate,mesocumulate,heteradcumulate and orthocumulate textures.The crystallization order for these rocks is olivine±chromian spinel→clinopyroxene→plagioclase→orthopyroxene→amphibole.The presence of primary magmatic amphiboles in the cumulate rocks shows that the parent magma evolved under hydrous conditions.Geochemically,the studied rock units are characterized by low TiO2(0.18-0.57 wt.%),P2 O5(<0.05 wt.%),K2 O(0.01-0.51 wt.%)and total alkali contents(0.12-3.04 wt.%).They indicate fractionated trends in the chondrite-normalized rare earth element(REE)plots and multi-element diagrams(spider diagrams).The general trend of the spider diagrams exhibit slight enrichment in large ion lithophile elements(LILEs)relative to high field strength elements(HFSEs)and positive anomalies in Sr,Pb and Eu and negative anomalies in Zr and Nb relative to the adjacent elements.The REE plots of these rocks display increasing trend from La to Sm,positive Eu anomaly(Eu/Eu*=1.06-1.54)and an almost flat pattern from medium REE(MREE)to heavy REE(HREE)region[(Gd/Yb)N=1-1.17].Moreover,clinopyroxenes from the cumulate rocks have low REE contents and show marked depletion in light REE(LREE)compared to MREE and HREE[(La/Sm)N=0.10-0.27 and(La/Yb)N=0.08-0.22].The composition of calculated melts in equilibrium with the clinopyroxenes from less evolved cumulate samples are closely similar to island arc tholeiitic(IAT)magmas.Modal mineralogy,geochemical features and REE modeling indicate that Sabzevar cumulate rocks were formed by crystal accumulation from a hydrous depleted basaltic melt with IAT affinity.This melt has been produced by moderate to high degree(~15%)of partial melting a depleted mantle source,which partially underwent metasomatic enrichment from subducted slab components in an intra-oceanic arc setting.
基金supported by the National Natural Science Foundation of China(Grant Nos.42372071,41421002)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201324)a research grant of the State Key Laboratory of Continental Dynamics(Grant No.SKLCD-04).
文摘Mafic enclaves in granites are generally considered to represent coeval mafic melts that derived from metasomatized mantle,which can provide valuable information about crust-mantle interaction.Exploring the genetic links between the mafic enclaves and their host monzogranite from the Triassic Zhashui Pluton,Qinling orogenic belt.The enclaves(220±4.6 Ma)and the monzogranite(220±2.8 Ma)display identical zircon U-Pb ages,and they also share similar trace element and zircon Lu-Hf isotopes,indicating a cognate source.The monzogranite displays zirconεHf(t)values of−0.99 to+1.98,while the mafic enclaves show similar values of−0.45 to+3.26;however,differences in mineral chemistry reveal different crystallization conditions.The amphibole from the mafic enclaves has higher temperature and pressure(757℃;2.65 kbar)compared to those of the host monzogranite(733℃;1.96 kbar),suggesting that mafic minerals in the enclaves crystallized at an early stage.Moreover,apatite in the mafic enclaves displays slightly higher volatile contents(0.72 wt%)than those of the monzogranite(0.66 wt%),indicating a volatile-rich condition.These results suggest that the mafic enclaves represent early hydrous mafic cumulates in the granitic chamber,and subsequent magma convection would have led to the formation of the mafic enclaves.
文摘The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triassic cumulate hornblende gabbro was identified in the southern margin of the Gangdese magmatic belt.The gabbro exhibits cumulate structure,with hornblende and plagioclase as the primary mineral phases.Isotopic data indicate a hydrous magma source derived from a depleted mantle wedge that has been modified by slab dehydration.Geochemical discriminations suggest that the gabbro was formed in an intraoceanic arc setting,with crystallization ages of ca.220-213 Ma.Hornblende,hornblendelagioclase and ilmenite thermometers reveal that the crystallization temperature of 900-750°C for the gabbro.Hornblende and hornblende-plagioclase geobarometers yield an emplacement depth at ca.14.5-19.5 km.This gabbro constitutes a line of evidence for an intraoceanic arc magmatism that is coeval with the counterparts in the southern Turkey,revealing an intraoceanic subduction system within the Neotethys from west to east in the Late Triassic and that the oceanization of the Neotethys was much earlier than previous expectation.
基金supported by National Key Research and Development Program of China(No.2023YFC2907600)the National Natural Science Foundation of China(Nos.52074263,52274145 and 52034007)+1 种基金the Postdoctoral Fellowship Program(Grade C)of China Postdoctoral Science Foundation(No.GZC20241925)the Fundamental Research Funds for the Central Universities(No.2024QN11002).
文摘Cyclic impact induces ongoing fatigue damage and performance degradation in anchoring structures,ser-ving as a critical factor leading to the instability of deep roadways.This paper takes the intrinsic spatio-temporal relationship of macro-microscopic cumulative damage in anchoring structures as the main thread,revealing the mechanism of bearing capacity degradation and progressive instability of anchoring structure under cyclic impact.Firstly,a set of impact test devices and methods for the prestressed solid anchor bolt anchoring structure were developed,effectively replicating the cyclic impact stress paths in situ.Secondly,cyclic impact anchoring structure tests and simulations were conducted,which clarifies the damage evolution mechanism of the anchoring structure.Prestress loss follows a cubic decay func-tion as the number of impacts increases.Under the same impact energy and pretension force,the impact resistance cycles of extended anchoring and full-length anchoring were increased by 186.7%and 280%,respectively,compared to end anchoring.The rate of internal damage accumulation is positively corre-lated with impact energy and negatively correlated with anchorage length.Internal tensile cracks account for approximately 85%.Stress transmission follows a fluctuating pattern.Compared to the extended anchoring,the maximum vibration velocity of the exposed end particles in the full-length anchoring was reduced by 59.31%.Damage evolution exhibits a pronounced cumulative mutation effect.Then,a three-media,two-interface mechanical model of the anchoring structure was constructed.It has been clarified that the compressive stress,tensile stress,and oscillation effect arising from rapid transi-tions between compression and tension are the primary internal factors responsible for the degradation of the anchoring structure’s bearing capacity.Finally,the progressive instability mechanism of the anchoring structure under cyclic impact was elucidated.The mutual feedback and superposition of media rupture,interface debonding,and bearing capacity degradation result in overall failure.The failure pro-cess involves stages dominated by oscillation-compression,tensile stress,and compression failure.A tar-geted control strategy was further proposed.This provides a reference for maintaining the long-term stability of deep roadways under dynamic impact loads.
基金supported by National Natural Science Foundation of China (Grants Nos. 40872146 and 40672147)China Geological Survey (Grant Nos. 1212010561605 and 1212010911070)Institute of Geology, Chinese Academy of Geological Sciences (Grant No. J0910)
文摘Metabasites consisting of metamorphic ultra-mafic rocks, cumulate gabbro, gabbro (diabase), basalt, and plagiogranite are exposed at the Taoxinghu area in central Qiangtang, northern Tibetan Plateau. Zircon SHRIMP U-Pb dating for the cumulate gabbro yields a weighted mean age of 467±4 Ma, which is the oldest and most reliable magmatic age in this area. Zircon 176Hf/177Hf ratios range from 0.282615 to 0.282657, with εHf(t) values of 5.02±0.28, indicating that the cumulate gabbro was mainly derived from the depleted mantle. In addition, geochemical data of metabasites suggest that they have similar characteristics to those in the mid-ocean ridge basalts (MORB). The Taoxinghu metabasites may represent the fragment of Early Paleozoic ophiolite in the "Central Uplift" of the Qiangtang, northern Tibetan Plateau.
文摘Mafic xenoliths occur in Mesozoic diorites from nine localities in eastern Inner Mongolia from the Da Hinggan Mrs. to Huabei craton. Their petrologic and geochemical features suggest that they are an intact suite of cumulate complex whose mineral assemblages contain typical patent mantle metasomatism minerals such as pargosite, phlogopite and apatite. Their REEs and trace element characteristics suggest a comagmatic relationship in these cumulates with different compositions. Isotopic dating of the xenoliths indicates that they are products of the mantle magmatic underplating in the Early Mesozoic (237—224 Ma), and they may provide direct evidence for the crust-mantle interaction and vertical accretion of continental crust under a background of the mantle upwelling in the Early Mesozoic in Huabei region.
基金Supported by Science and Technology Innovation 2030-Major Projects,No.2021ZD0202000National Key Research and Development Program of China,No.2019YFA0706200+2 种基金National Natural Science Foundation of China,No.82371535Science and Technology Innovation Program of Hunan Province,No.2023RC3083Fundamental Research Funds for the Central Universities of Central South University,No.2023ZZTS0838.
文摘BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity variables affect MDD.We hypothesize that high-level trait-and state-related stress-sensitivity factors may have different cumulative effects on the clinical symptoms and follow-up outcomes of MDD.AIM To investigate how stress-sensitivity factors added up and affected MDD clinical symptoms and follow-up results.METHODS In this prospective study,281 MDD patients were enrolled from a tertiary care setting.High-level stress-sensitivity factors were classified as trait anxiety,state anxiety,perceived stress,and neuroticism,with a total score in the top quartile of the research cohort.The cumulative effects of stress-sensitivity factors on cognitive dysfunction,disability and functional impairment,suicide risk,and depressive and anxiety symptoms were examined using an analysis of variance with linear trend analysis.Correlations were investigated further using multiple regression analysis.RESULTS Regarding high-level stress-sensitivity factors,53.40%of patients had at least one at baseline,and 29.61%had two or more.Four high-level stress-sensitivity components had significant cumulative impacts on MDD symptoms at baseline(all P<0.001).Perceived stress predicted the greatest effect sizes of state-related factors on depressive symptoms(partialη^(2)=0.153;standardizedβ=0.195;P<0.05).The follow-up outcomes were significantly impacted only by the high-level trait-related components,mainly when it came to depressive symptoms and suicide risk,which were predicted by trait anxiety and neuroticism,respectively(partialη^(2)=0.204 and 0.156;standardizedβ=0.247 and 0.392;P<0.05).CONCLUSION To enhance outcomes of MDD and lower the suicide risk,screening for stress-sensitivity factors and considering multifaceted measures,mainly focusing on trait-related ones,should be addressed clinically.
文摘Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections have the form ∝ L^(-ω),then we find ω=1.546(30) andω=1.509(14) as the best estimates.These are obtained from the finite-size scaling of the susceptibility data in the range of linear lattice sizes L ∈[128,2048] at the critical value of the Binder cumulant and from the scaling of the corresponding pseudocritical couplings within L∈[64,2048].These values agree with several other MC estimates at the assumption of the power-law corrections and are comparable with the known results of the ε-expansion.In addition,we have tested the consistency with the scaling corrections of the form ∝ L^(-4/3),∝L^(-4/3)In L and ∝L^(-4/3)/ln L,which might be expected from some considerations of the renormalization group and Coulomb gas model.The latter option is consistent with our MC data.Our MC results served as a basis for a critical reconsideration of some earlier theoretical conjectures and scaling assumptions.In particular,we have corrected and refined our previous analysis by grouping Feynman diagrams.The renewed analysis gives ω≈4-d-2η as some approximation for spatial dimensions d <4,or ω≈1.5 in two dimensions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102480,52278543 and 51978660)Natural Science Foundation of Jiangsu Province(Grant No.BK20231489)。
文摘Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.
文摘BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS.However,the optimal timing for polyp screening and preventive intervention using entero-scopic polypectomy remains uncertain.This is primarily due to the extremely low incidence of the condition and the paucity of data regarding the natural risk of requiring surgery and its age distribution in PJS patients.In order to develop recommendations on the appropriate timing of polyp screening and preventive intervention in PJS,a comprehensive understanding of the natural surgical risks AIM To investigate the natural surgical risks associated with polyps in PJS and to clarify their age distribution.METHODS A web-based open survey was launched to collect information from Chinese individuals suspected of having PJS.The questionnaire was distributed to the PJS instant messaging groups using a quick response code method.The data were analyzed using descriptive statistical methods,and the cumulative incidence of surgery was calculated using the Kaplan-Meier method.RESULTS Of the 442 patients enrolled,301(68.10%)had undergone 506 surgical procedures prior to enteroscopy or the survey deadline.Among the 506 surgical procedures,388(76.68%)were performed on patients aged between 6 and 25 years.The cumulative incidence rates of the first surgical procedure at 5,10,15,20,25,and 30 years of age were 5.0%(95%confidence interval[CI]:2.9%-7.0%),20.6%(95%CI:16.6%-24.4%),40.5%(95%CI:35.5%-45.1%),58.0%(95%CI:52.7%-62.7%),72.6%(95%CI:67.3%-77.0%),and 82.4%(95%CI:77.0%-86.5%),respectively.The primary indications for the first surgical procedures were intussusception(81.40%),obstruction(13.95%),and gas-trointestinal bleeding(4.65%).The cumulative incidence rates of requiring a second surgical procedure within 1,3,5,10 and 15 years following the first surgical procedure were 3.7%(95%CI:1.5%-5.8%),12.5%(95%CI:8.6%-16.2%),20.3%(95%CI:15.6%-24.8%),37.0%(95%CI:33.1%-45.3%),54.2%(95%CI:46.8%-60.5%),respectively.Patients who underwent their first surgical procedure at the age of nine years or younger presented an elevated risk of requiring a second surgical procedure(P<0.01).CONCLUSION Chinese patients with PJS have a high natural risk of undergoing surgery.Without preventive intervention,these procedures may become necessary at an early age and may be repeated.Early screening and regular surveillance,with preventive intervention if necessary,should commence at six years of age.
文摘Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purpose of this study was to systematically alter the trunk lean angle in distance running using an auditory real-time feedback approach and to derive dose-response relationships between sagittal plane trunk lean angle and lower extremity(cumulative)joint loading to guide overuse load management in clinical practice.Methods:Thirty recreational runners(15 males and 15 females)ran at a constant speed of 2.5 m/s at 5 systematically varied trunk lean conditions on a force-instrumented treadmill while kinematic and kinetic data were captured.Results:A change in trunk lean angle from-2°(extension)to 28°(flexion)resulted in a systematic increase in stance phase angular impulse,cumulative impulse,and peak moment at the hip joint in the sagittal and transversal plane.In contrast,a systematic decrease in these parameters at the knee j oint in the sagittal plane and the hip joint in the frontal plane was found(p<0.001).Linear fitting revealed that with every degree of anterior trunk leaning,the cumulative hip joint extension loading increases by 3.26 Nm·s/kg/1000 m,while simultaneously decreasing knee joint extension loading by 1.08 Nm·s/kg/1000 m.Conclusion:Trunk leaning can reduce knee joint loading and hip joint abduction loading,at the cost of hip joint loading in the sagittal and transversal planes during distance running.Modulating lower extremity joint loading by altering trunk lean angle is an effective strategy to redistribute joint load between/within the knee and hip joints.When implementing anterior trunk leaning in clinical practice,the increased demands on the hip musculature,dynamic stability,and the potential trade-off with running economy should be considered.
基金supported by Basic Science Research Program through the National Natural Science Foundation of China(Grant No.61867003).
文摘As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wind speed correlation,a multi-scenario PLF calculation method that combines random sampling and segmented discrete wind farm power was proposed.Firstly,based on constructing discrete scenes of wind farms,the Nataf transform is used to handle the correlation between wind speeds.Then,the random sampling method determines the output probability of discrete wind power scenarios when wind speed exhibits correlation.Finally,the PLF calculation results of each scenario areweighted and superimposed following the total probability formula to obtain the final power flow calculation result.Verified in the IEEE standard node system,the absolute percent error(APE)for the mean and standard deviation(SD)of the node voltages and branch active power are all within 1%,and the average root mean square(AMSR)values of the probability curves are all less than 1%.
基金funded by the National Natural Science Foundation of China(No.51974206)the Hubei Province Safety Production Special Fund Science and Technology Project(No.KJZX202007007).
文摘In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion-resistant and cost-effective.However,the damage mechanisms of GFRP bolts under blasting dynamic loads are still unclear,especially compared to metal bolts.This study investigates the cumulative damage of fully grouted GFRP bolts under blasting dynamic loads.The maximum axial stress at the tails of the bolts is defined as the damage variable,based on the failure characteristics of GFRP bolts.By combining this with Miner's cumulative damage theory,a comprehensive theoretical and numerical model is established to calculate cumulative damage.Field data collected from the Jinchuan No.3 Mining Area,including GFRP bolts parameters and blasting vibration data are used for further analysis of cumulative damage in fully grouted GFRP bolts.Results indicate that with an increasing number of blasts,axial stress increases in all parts of GFRP bolts.The tail exhibits the most significant rise,with stress extending deeper into the anchorage zone.Cumulative damage follows an exponential trend with the number of blasts,although the incremental damage per blast decelerates over time.Higher dynamic load intensities accelerate damage accumulation,leading to an exponential decline in the maximum loading cycles before failure.Additionally,stronger surrounding rock and grout mitigate damage accumulation,with the effect of surrounding rock strength being more pronounced than that of grout.In contrast,the maximum axial stress of metal bolts increases quickly to a certain point and then stabilizes.This shows a clear difference between GFRP and metal bolts.This study presents a new cumulative damage theory that underpins the design of GFRP bolt support systems under blasting conditions,identifies key damage factors,and suggests mitigation measures to enhance system stability.
文摘Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occurrence of pressure injuries(PIs).Methods:In this retrospective longitudinal study,we obtained health-related data from the Medical Information Mart for Intensive Care IV database,including sociodemographic,disease-related variables,and ICU treatment variables.The daily CFB adjusted for body weight was calculated,and the occurrence of PIs during the ICU stay was recorded.A group-based trajectory model was used to explore the different CFB trajectories.Binary logistic regression was used to analyze the relationship between the CFB trajectory group and PIs.Results:Among the 4,294 included participants,we identified four distinct trajectories of CFB in ICU patients:the rapid accumulation group(12.5%),the slow accumulation group(28.5%),the neutral balance group(41.7%),and the negative decrease group(17.3%).After adjusting for some sociodemographic,disease-related variables,and ICU treatment variables,the rapid accumulation group had an OR of 1.63(95%CI:1.30,2.04)for all stages of PIs and an OR of 1.36(95%CI:1.08,1.72)for stage II or higher PIs compared to the neutral balance group.Conclusions:Four unique trajectories of CFB were identified among patients in the ICU,including rapid accumulation,slow accumulation,neutral balance,and negative decrease.Rapid accumulation independently increased the risk of PIs during ICU stay.
文摘In November 2024,the Global Solar Council announced that the world cumulative solar capacity reached 2 terawatts,twice as much as in mid-2022,clearly showing that solar energy is set to lead the energy transition.
文摘Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.
基金funded by the Basic Scientific Research Fund,Science and Technology Innovation Base of Lanzhou,Institute of Earthquake Forecasting,China Earthquake Administration(Grants No.2020IESLZ03 and 2015IESLZ05)the National Key R&D program of China(Grant No.2017YFC1500906)
文摘On 18 December 2023,a MS 6.2 earthquake struck the Jishishan area in Northwest China,located at the border of the Qinghai-Tibet and Loess Plateau.The earthquake triggered shallow loess landslides,small rock failures,and soil cracks,mainly along hilly gullies and cut slopes at the edges of terraced fields.A rare large-scale flowslide also occurred in irrigated farmland.These seismic landslides and collapses blocked roads,buried farmland,damaged houses,and resulted in many casualties.Field investigations revealed that these geological hazards were concentrated around cultivated land.Consequently,cultivated land was introduced as an engineering geological zoning factor into the seismic geological hazard risk assessment for Jishishan area.The Newmark cumulative displacement model was refined by incorporating lithological uncertainties via the Monte Carlo method.Comparative analysis of coseismic geohazards with and without considering cultivated land suggests that,in loess-covered areas with cultivation activities,the consideration of the disturbed characteristics of soils provides a more accurate probabilistic risk assessment of seismic geohazards.Human cultivation and irrigation activities affect the physical properties of surface soil,the terraced fields around earthquake prone areas have a risk of earthquake-induced geological hazards.This study may offer valuable insights for hazard prevention and mitigation in high fortification intensity loess covered areas.
