According to low earth orbit（LEO） satellite systems with users of different levels, a dynamic channel reservation scheme based on priorities is proposed. Dynamic calculation of the thresholds for reserved channels i...According to low earth orbit（LEO） satellite systems with users of different levels, a dynamic channel reservation scheme based on priorities is proposed. Dynamic calculation of the thresholds for reserved channels is the key of this strategy. In order to obtain the optimal thresholds, the traffic is predicted based on the high-speed deterministic movement property of LEO satellites firstly. Then, a channel allocation model based on Markov is established. Finally, the solution of the model is obtained based on the genetic algorithm. Without user location, this strategy effectively reduces handover failures and improves channel utilization by adjusting dynamically the thresholds according to traffic conditions. The simulation results show that the system＇s overall quality of service can be improved by this strategy.展开更多
In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multipl...In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel.展开更多
Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very sca...Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme.展开更多
Ovarian aging is characterized by a progressive decline in oocyte quality and quantity with age.Icariin(ICA),a flavonoid compound derived from Epimedium species,has demonstrated potential as an agent for ovarian resto...Ovarian aging is characterized by a progressive decline in oocyte quality and quantity with age.Icariin(ICA),a flavonoid compound derived from Epimedium species,has demonstrated potential as an agent for ovarian restoration.In this study,a subcutaneous implantation system using gelatin methacryloyl(GelMA)hydrogel embedded with ICA was developed to restore ovarian function in aged female mice.Mice were assigned to receive subcutaneous implantation of GelMA alone(GelMA group),GelMA containing ICA(GelMA/ICA group),or a sham operation.Ovarian morphology,serum hormone levels,follicle counts across developmental stages,and reproductive outcomes were evaluated.In vitro fertilization(IVF)and embryo culture assays were performed to assess oocyte developmental potential,while a 10 day natural mating trial was conducted to determine fertility restoration.RNA sequencing(RNA-seq)and RT-qPCR were performed to elucidate the underlying molecular mechanisms.Results showed that GelMA/ICA treatment significantly increased ovarian index(0.19±0.01 vs.0.13±0.01,P<0.0001)and follicle numbers at all developmental stages,including primordial(383.33±151.65 vs.107.14±32.26,P<0.0001),primary(203.33±83.22 vs.91.43±27.04,P=0.003),and secondary follicles(154.17±52.00 vs.59.28±20.50,P=0.029)compared to the sham controls.Hormonal analyses revealed a significant reduction in serum follicle-stimulating hormone(FSH,11.97±3.53 vs.53.10±17.89 ng/mL,P=0.0008),accompanied by elevated anti-Müllerian hormone(AMH,22.97±2.26 vs.5.54±1.56 ng/mL,P<0.0001)and estradiol(E2,315.30±37.62 vs.168.5±14.78 pg/mL,P<0.0001).Oocyte yield and developmental potential improved significantly,as reflected by the increased number of superovulated MII oocytes(17.83±5.15 vs.4.83±4.79,P=0.0002),and higher proportions of two-cell(85.90%±6.16%vs.50.00%±10.00%,P=0.0009),four-cell(81.67%±9.76%vs.50.00%±10.00%,P=0.0061),and blastocyst stage embryos(64.25%±10.55%vs.23.33%±15.28%,P=0.0067).Live birth numbers were significantly increased following GelMA/ICA treatment(6.90±3.21 vs.1.72±2.05,P=0.0001).Transcriptomic analysis revealed up-regulation of genes associated with cytoskeletal organization(Vil1,Tubb3),lipid storage(Soat2,Plin4),oocyte maturation(Oosp2),and cytokine secretion(Cxcl12).Collectively,these findings suggest that GelMA/ICA hydrogels effectively reverse key hallmarks of ovarian aging and restore reproductive function in aged mice,offering a promising platform for fertility preservation and a novel therapeutic for future investigations into ovarian aging.展开更多
Accurately forecasting ecosystem services is critical for enhancing our understanding and improving management practices within nature reserves,particularly in light of climate change,land use/cover changes,and their ...Accurately forecasting ecosystem services is critical for enhancing our understanding and improving management practices within nature reserves,particularly in light of climate change,land use/cover changes,and their complex interactions.However,existing studies often fail to fully consider vegetation response,constituting a gap in the comprehensive assessment of changes in ecosystem services.Therefore,a coupled model framework integrating climate change,land use change,and vegetation dynamics was developed to allow for the simulation of dynamic ecosystem service scenarios throughout the twenty-first century.The Jiulianshan National Nature Reserve in Jiangxi Province was considered as the study area.The results showed that ecosystem services and their synergistic effects will be optimized under scenarios that emphasize strict protection of ecological lands and incorporating the SSP1-2.6 scenario.However,sustaining optimized ecosystem services poses significant challenges in scenarios characterized by resource-intensive development and ongoing climate warming,as in the SSP5-8.5 scenario.Notably,discernible variations exist in balancing and synergizing the management of ecosystem services across diverse land uses and forest types.Our study underscores the importance of integrating vegetation response into the framework of ecosystem service forecasting,which is essential for assisting nature reserves in effectively addressing the multifaceted risks associated with climate change and rapid socio-economic development.展开更多
Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantiall...Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantially enhance land resources.This study highlights the necessity for a precise correlation between land development initiatives and constraints in order to optimize efficiency and enhance the effectiveness of such projects,with the core being the seamless integration of land development engineering and techniques to eliminate agricultural constraints.This study employs a systems engineering approach to classify improvement factors into mobile and fixed categories,elucidating the integration methods of constraint factors.Adhering to the Wooden Barrel Principle,these constraints were rigorously analyzed based on soil quality,land topography,water availability,and agricultural infrastructure.An innovative method of engineering type combination is proposed,which effectively explains the correlation between natural factors combination,project type combination,and target factors combination.It provides a convenient way for the selection of barren grassland development projects and lays a foundation for land planning,development project establishment,program selection,engineering design,and budget preparation.Taking Tang County of China as an example,it is divided into 19 factor improvement areas,a quick reference table of engineering types is established,and 14 main types of engineering combinations are obtained,which lays a foundation for the application of theoretical framework in practice.展开更多
Objective: To compare the functional outcomes of patients who had parotid masseter fascia reserved and unreserved flap elevating scheme in parotidectomy, especially the morbidity of Frey's syndrome. Methods: Twent...Objective: To compare the functional outcomes of patients who had parotid masseter fascia reserved and unreserved flap elevating scheme in parotidectomy, especially the morbidity of Frey's syndrome. Methods: Twenty-three patients (group A) had parotid masseter fascia reserved in the parotidectomy, 32 patients (group B) had parotid masseter fascia unreserved in the operation. Compare the morbidity of gustatory sweating syndrome of the two groups. Results: Follow-up after 6 months to 2.5 years, gustatory sweating syndrome occurred in 4 patients of group A (17%), 17 patients in group B (57%). Conclusion: Reservation technic of the parotid masseter fascial in parotidectomy could prevent regeneration of parasympathetic nerve and thus prevent Frey's syndrome post-operation.展开更多
This paper had described the influence of restoration and reservation of Xi'an Qujiang Pond Ruins Park on urban landscape with an emphasis,proposed to promote urban landscape development by making use of cultural ...This paper had described the influence of restoration and reservation of Xi'an Qujiang Pond Ruins Park on urban landscape with an emphasis,proposed to promote urban landscape development by making use of cultural ruins. It analyzed the good and bad effects of Xi'an Qujiang Pond Ruins Park on urban landscape and concluded that cultural ruins should be used to shape new outlook of urban landscape,so as to discuss the momentous significance of cultural ruins in urban landscape.展开更多
[Objective] The aim was to explore the spatial and temporal distribution characteristics of wind energy resource and preservation in central and west area of Hexi Corridor. [Method] By dint of the wind speed data from...[Objective] The aim was to explore the spatial and temporal distribution characteristics of wind energy resource and preservation in central and west area of Hexi Corridor. [Method] By dint of the wind speed data from 1955 to 2007 in ten meteorological observation station in central and west area of Hexi Corridor,and special wind tower fine data from January to December in 2007,the distribution and reserves of the region＇s wind energy resources were studied. [Result] The results showed that environmental wind speed was relatively stable in central and west Hexi Corridor. There were no distinct changes in climate characteristics distribution. There were regional differences in the distribution of wind energy,and there was a large numerical area of wind energy in Gazhou County and Yumen City; Wind energy in the region generally was higher. The wind energy density was above 100 w/m2 in the 10 m layer,around 140 w/m2 in most places,and was more than 200 w/m2 in the large number area. The wind grew in vertical direction along with the linear growth of height. Each 10 m high wind increased to 15 w/m2 averagely,50m layer wind energy was greater than the general 240 w/m2 and there were obvious changes on daily and annual with wind energy in central and west area of Hexi Corridor. The duration from March to May was a wind energy-intensive stage,10m height from the ground in the wind around 10：00 in low-value. After growing from 11：00,it met the day largest number at 18：00,and then reduced gradually. Effective wind speed hours in the region in general were more than 6 200 h,and the value in the large areas was close to 7 600 h. [Conclusion] The study laid basis for the development and application of wind energy in central and west area of Hexi Corridor.展开更多
[Objective] The aim was to explore the effects of cultivation and seed reservation methods on quality and disease/insect damages of maca seed in cold highland areas,providing scientific references for cultivation and ...[Objective] The aim was to explore the effects of cultivation and seed reservation methods on quality and disease/insect damages of maca seed in cold highland areas,providing scientific references for cultivation and seed reservation and planning of maca vareity.[Method] Yellow,purple and black maca were selected and cultivated in the region with an elevation of 3 000 m to be experimental materials and cultivation and seed reservation methods were as follows：maca seed reservation in situ,seed reservation in original soils maca grown after selection of maca balls,and seed reservation in the region with an elevation of 2 700 m after selection of maca ball,seed reservation in greenhouses in the region with an elevation of 2 400 m after selection of maca ball,and growing selected balls in greenhouses and transplanting to the farmlands with an elevation of 2 400 m.[Result] The cultivation and seed reservation methods had significant or extremely significant effects on maca phenological phase;maca in different colors were treated by different cultivation and seed reservation methods,showing insignificant effects on disease and insect damages.[Conclusion] It can be concluded that the selected maca balls stored for 15 d as per the method grown in the region with an elevation of 2 700 m will improve seed quality and reduce disease or insect damages.展开更多
[Objective] The aim is to conduct systematic diagnoses on the eco-vulnerability in Daqinggou National Natural Reserve. [Method] A kind of ＂problem pile＂ is proposed about 58 interrelated problems of ecological vulne...[Objective] The aim is to conduct systematic diagnoses on the eco-vulnerability in Daqinggou National Natural Reserve. [Method] A kind of ＂problem pile＂ is proposed about 58 interrelated problems of ecological vulnerability by field survey and questionnaires and a ladder diagram of interrelations among the problems is established. The root problems, basic problems, core problems, interrelation and solving approaches are proposed, as well. [Result] It can be concluded from system diagnosis that fragile ecosystem of the Reserve can be observed from poor disasterresistibility, lower species diffusivity, lower system metabolism and poor system restorability. According to system diagnoses, management planning and control subsystem is key for protection of system vulnerability and solving different problems in process-oriented system. Conservation of the Reserve and ecological education on tourists are indispensible. It can be concluded from diagnoses that plant updating, evolution and ill growth in the Reserve are the focus of the vulnerable ecosystem, which influence species diffusivity, system metabolism and restorability and constitute central nodes of process-oriented and effect-oriented subsystems. [Conclusion] The research provides references for solving vulnerability issues of conservation and tourism management in Daqinggou National Nature Reserve.展开更多
The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It ha...The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It has been suggested that the size of the brain(brain reserve) and the extent of neural connections acquired through life(neural reserve) set a threshold beyond which noticeable impairments occur.In contrast,cognitive reserve refers to the brain's ability to adapt and reo rganize stru cturally and functionally to resist damage and maintain function,including neural reserve and brain maintenance,resilience,and compensation(Verkhratsky and Zorec,2024).展开更多
Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it pr...Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it protects a vital temperate mountainous forest ecosystem on the Loess Plateau.The reserve is centred around the Liupan Mountain range,one of China’s youngest mountain chains,formed by Himalayan tectonic movements.展开更多
Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value ...Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value of CT-FFR combined with CCTA–defined atherosclerotic extent in diabetic patients with coronary artery disease(CAD).Methods A retrospective pooled analysis of individual patient data was performed. Deep-learning-based vessel-specific CTFFR was calculated. All patients enrolled were followed-up for at least 5 years. Predictive abilities for major adverse cardiac events(MACE) were compared among three models(model 1), constructed using clinical variables;model 2, model 1+CCTA–derived atherosclerotic extent(Leiden risk score);and model 3, model 2+CT-FFR.Results A total of 480 diabetic patients [median age, 61(55–66) years;52.9% men] were included. During a median follow-up time of 2197(2126–2355) days, 55 patients(11.5%) experienced MACE. In multivariate-adjusted Cox models, Leiden risk score(HR: 1.06;95% CI: 1.01–1.11;P = 0.013) and CT-FFR ≤ 0.80(HR: 6.54;95% CI: 3.18–13.45;P < 0.001) were the independent predictors. The discriminant ability was higher in model 2 than in model 1(C-index, 0.75 vs. 0.63;P < 0.001) and was further promoted by adding CT-FFR to model 3(C-index, 0.81 vs. 0.75;P = 0.002). Net reclassification improvement(NRI) was 0.19(P = 0.009) for model 2 beyond model 1. Of note, adding CT-FFR to model 3 also exhibited significantly improved reclassification compared with model 2(NRI = 0.14;P = 0.011).Conclusion In diabetic patients with CAD, CT-FFR provides robust and incremental prognostic information for predicting longterm outcomes. The combined model exhibits improved prediction abilities, which is beneficial for risk stratification.展开更多
CHINA Wuliangshan National Nature Reserve Spanning a significant altitudinal range from 1,600 to 3,371 metres and encompassing a total area of 31,585 hectares,the Wuliangshan National Nature Reserve protects one of th...CHINA Wuliangshan National Nature Reserve Spanning a significant altitudinal range from 1,600 to 3,371 metres and encompassing a total area of 31,585 hectares,the Wuliangshan National Nature Reserve protects one of the most intact and pristine forest ecosystems in southern Yunnan Province.展开更多
Elk are seen at the Tian’ezhou National Nature Reserve for Elk in Shishou,Hubei Province,on 27 November 2025.The reserve’s elk population has risen from just 64 in the 1990s to more than 4,500 today.
Ungulates serve as key components in maintaining ecosystem stability,and their ecological functions are closely linked to the integrity of giant panda habitats within Wanglang National Nature Reserve.Assessment of ung...Ungulates serve as key components in maintaining ecosystem stability,and their ecological functions are closely linked to the integrity of giant panda habitats within Wanglang National Nature Reserve.Assessment of ungulate habitat suitability in this reserve can provide critical insights into the distribution patterns of ungulate communities across protected areas while informing conservation strategy optimization.Therefore,six ungulate species were monitored,including Tufted deer(Elaphodus cephalophus),Chinese serow(Capricornis milneedwardsii),Chinese goral(Naemorhedus griseus),Sichuan takin(Budorcas taxicolor),Reeve's muntjac(Muntiacus reevesi),and Wild boar(Sus scrofa)in Wanglang National Nature Reserve.The infrared camera monitoring data(a total of 83 sites)and 23 environmental variables were collected from January 2011 to May 2019,the relative abundance index(RAI),independent samples t-test,and optimized MaxEnt model were employed to evaluate the habitat suitability of six ungulate species.Our findings were as follows:(1)there were significant differences in the annual RAI among the six ungulate species(P<0.01).(2)the suitable habitat area varied among species:Tufted deer occupied 9578 hm^(2)(31.08%of the total),Chinese serow 10,093 hm^(2)(32.75%);Chinese goral 9936 hm^(2)(32.24%);Sichuan takin 10,992 hm^(2)(35.67%);Reeve's muntjac 9542 hm^(2)(30.96%);and Wild boar 9642 hm^(2)(31.28%).(3)the spatial niche overlaps between each pair of the six ungulates were all relatively high(D=0.77-0.89).(4)the annual average temperature,precipitation during the coldest season,and vegetation were the key factors influencing habitat selection.These findings offer valuable references for the conservation of ungulates in natural reserve and are conducive to formulating more scientific and effective.展开更多
In recent years,the combined effects of seismic disturbances and extreme rainfall events have intensified water turbidity and sedimentation in several lakes within the Jiuzhaigou Nature Reserve located within the Jiuz...In recent years,the combined effects of seismic disturbances and extreme rainfall events have intensified water turbidity and sedimentation in several lakes within the Jiuzhaigou Nature Reserve located within the Jiuzhaigou watershed in Southwest China.In July 2024,turbidity events were observed in multiple core lakes,with noticeable impacts on local ecological functions and landscape values.To quantitatively characterize lake physical changes and explore their driving mechanisms,this study developed an integrated“air-space-ground”lake morphological measurement framework that combines unmanned aerial vehicle(UAV),unmanned surface vehicles(USV),and satellite remote sensing to enable high-precision acquisition of lake bathymetry,relationships between water level and surface area,and storage capacity.Additionally,time-series analyses of fractional vegetation cover(FVC)and the Revised Universal Soil Loss Equation(RUSLE)model were applied to characterize the patterns of change in vegetation cover and soil erosion intensity before and after seismic and extreme rainfall events.The results show that:(1)The physical morphology of the lakes has changed significantly compared with the field measurements conducted in 2004.The surface areas of the Arrow Bamboo Lake and the Rhinoceros Lake decreased by 15.2%~17.0%,and lake storage capacity decreased by 20%~33%.In Long Lake,the difference between the minimum and maximum daily water levels reached 13.21 m,and since 2021,the annual mean water level has exhibited a continuous decline at a rate of 1.46 m·a^(-1).(2)Based on the results of the FVC time series analysis,the two earthquake events resulted in decreases in vegetation cover by 19.14%and 13.19%,and these decreases were accompanied by enhanced soil erosion under heavy rainfall conditions.This process facilitated the transport of large amounts of terrestrial material into the lakes,thereby contributing to water turbidity and sediment accumulation.RUSLE-based estimates further indicate that the two earthquakes increased the peak mean soil erosion modulus by 7.61 t·ha^(-1)·a^(-1)and 4.10 t·ha^(-1)·a^(-1),respectively,relative to pre-earthquake conditions.Based on these findings,it is recommended to implement slope vegetation restoration on the upstream areas of the core lakes,strengthen slope protection in accident-prone locations,and monitor water-sediment dynamics during heavy rainfall periods,to mitigate sedimentation risks and enhance the stability of the scenic area's ecosystem.展开更多
Objective:To identify predictors of pregnancy and live birth outcomes in assisted reproductive technology(ART)cycles based on patient characteristics,hormonal profile,and embryo transfer variables.Methods:This retrosp...Objective:To identify predictors of pregnancy and live birth outcomes in assisted reproductive technology(ART)cycles based on patient characteristics,hormonal profile,and embryo transfer variables.Methods:This retrospective cohort study included 50 fresh in vitro fertilization(IVF)/intracytoplasmic sperm injection(ICSI)cycles selected from ART participants at a single tertiary ART center.Controlled ovarian stimulation was performed using recombinant follicle stimulating hormone(rFSH),gonadotropin-releasing hormone(GnRH)antagonist,and menotropins;oocyte retrieval occurred 36 h after trigger and embryo transfer was performed on day 3 or 5.Outcomes(chemical pregnancy,ongoing pregnancy,abortion,live birth)were compared across groups stratified by maternal age,antral follicle count(AFC),anti-Müllerian hormone(AMH),baseline luteinizing hormone(LH),estradiol(E2)at trigger,and endometrial thickness.Multivariate regression was used to identify independent predictors of live birth.Results:A total of 124 ART patients were screened during the study period,of whom 50 participants meeting the eligibility criteria were included in the final analysis.The median age of the participants was 35.8 years[interquartile range(IQR)32.5–39.6].The median AFC was 8(IQR 4–14),AMH level was 1.4 ng/mL(IQR 0.7–2.9),and the median endometrial thickness at embryo transfer was 10.2 mm(IQR 9.0–11.3).Chemical,ongoing,abortion,and live birth rates were 62%,32%,12%,and 16%,respectively.Younger maternal age(<35 years),higher AFC(>12),AMH 1–4 ng/mL,and endometrial thickness≥10 mm were associated with more favorable pregnancy outcomes.In multivariate analysis,higher baseline LH(β=0.089;95%CI 0.017–0.162;P=0.02)and greater endometrial thickness(β=0.145;95%CI 0.011–0.278;P=0.04)independently predicted live birth,whereas age,AFC,AMH,and E2 did not.Conclusions:Maternal age,ovarian reserve markers,LH levels,and endometrial thickness collectively influence ART outcomes.Baseline LH and endometrial receptivity are key independent predictors of live birth and may guide individualized treatment strategies.展开更多
基金supported by the National Natural Science Foundation of China(7130108161373137)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20130877BK2012833)
文摘According to low earth orbit（LEO） satellite systems with users of different levels, a dynamic channel reservation scheme based on priorities is proposed. Dynamic calculation of the thresholds for reserved channels is the key of this strategy. In order to obtain the optimal thresholds, the traffic is predicted based on the high-speed deterministic movement property of LEO satellites firstly. Then, a channel allocation model based on Markov is established. Finally, the solution of the model is obtained based on the genetic algorithm. Without user location, this strategy effectively reduces handover failures and improves channel utilization by adjusting dynamically the thresholds according to traffic conditions. The simulation results show that the system＇s overall quality of service can be improved by this strategy.
基金support by the National Natural Science Foundation of China (61401360)the Fundamental Research Funds for the Central Universities (3102017zy026)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China (2016JM6017)the Scientific Research Program Funded by Shaanxi Provincial Education Department (16JK1702)
文摘In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel.
文摘Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme.
基金supported by the National Natural Science Foundation of China(82271671)Nanjing Drum Tower Hospital Academic Innovation Peak Fund(2024-DF-02)+4 种基金Clinical Trials from Nanjing Drum Tower Hospital(2023-LCYJ-MS-05)Nanjing International Science and Technology Cooperation Program(202201027)to L.D.Research Project of State Key Laboratory of Reproductive Medicine and Offspring Health(SKLRM-2022D2)Changzhou Medical Center of Nanjing Medical University(CMCM202203)Clinical Trials from Nanjing Drum Tower Hospital(2022-LCYJ-ZD-02)to H.S.
文摘Ovarian aging is characterized by a progressive decline in oocyte quality and quantity with age.Icariin(ICA),a flavonoid compound derived from Epimedium species,has demonstrated potential as an agent for ovarian restoration.In this study,a subcutaneous implantation system using gelatin methacryloyl(GelMA)hydrogel embedded with ICA was developed to restore ovarian function in aged female mice.Mice were assigned to receive subcutaneous implantation of GelMA alone(GelMA group),GelMA containing ICA(GelMA/ICA group),or a sham operation.Ovarian morphology,serum hormone levels,follicle counts across developmental stages,and reproductive outcomes were evaluated.In vitro fertilization(IVF)and embryo culture assays were performed to assess oocyte developmental potential,while a 10 day natural mating trial was conducted to determine fertility restoration.RNA sequencing(RNA-seq)and RT-qPCR were performed to elucidate the underlying molecular mechanisms.Results showed that GelMA/ICA treatment significantly increased ovarian index(0.19±0.01 vs.0.13±0.01,P<0.0001)and follicle numbers at all developmental stages,including primordial(383.33±151.65 vs.107.14±32.26,P<0.0001),primary(203.33±83.22 vs.91.43±27.04,P=0.003),and secondary follicles(154.17±52.00 vs.59.28±20.50,P=0.029)compared to the sham controls.Hormonal analyses revealed a significant reduction in serum follicle-stimulating hormone(FSH,11.97±3.53 vs.53.10±17.89 ng/mL,P=0.0008),accompanied by elevated anti-Müllerian hormone(AMH,22.97±2.26 vs.5.54±1.56 ng/mL,P<0.0001)and estradiol(E2,315.30±37.62 vs.168.5±14.78 pg/mL,P<0.0001).Oocyte yield and developmental potential improved significantly,as reflected by the increased number of superovulated MII oocytes(17.83±5.15 vs.4.83±4.79,P=0.0002),and higher proportions of two-cell(85.90%±6.16%vs.50.00%±10.00%,P=0.0009),four-cell(81.67%±9.76%vs.50.00%±10.00%,P=0.0061),and blastocyst stage embryos(64.25%±10.55%vs.23.33%±15.28%,P=0.0067).Live birth numbers were significantly increased following GelMA/ICA treatment(6.90±3.21 vs.1.72±2.05,P=0.0001).Transcriptomic analysis revealed up-regulation of genes associated with cytoskeletal organization(Vil1,Tubb3),lipid storage(Soat2,Plin4),oocyte maturation(Oosp2),and cytokine secretion(Cxcl12).Collectively,these findings suggest that GelMA/ICA hydrogels effectively reverse key hallmarks of ovarian aging and restore reproductive function in aged mice,offering a promising platform for fertility preservation and a novel therapeutic for future investigations into ovarian aging.
基金supported by the National Natural Science Foundation of China (32160292, 32471681, and 32201575)Jiangxi “Double Thousand Plan”(jxsq2020101080)+1 种基金the Natural Science Foundation of Jiangxi Province (20224BAB205008, 20224BAB213033, and 20242BAB2538)Jiangxi Province Science and Technology+Water Resources” Joint Plan Project (2023KSG01001 and 2022KSG01010)
文摘Accurately forecasting ecosystem services is critical for enhancing our understanding and improving management practices within nature reserves,particularly in light of climate change,land use/cover changes,and their complex interactions.However,existing studies often fail to fully consider vegetation response,constituting a gap in the comprehensive assessment of changes in ecosystem services.Therefore,a coupled model framework integrating climate change,land use change,and vegetation dynamics was developed to allow for the simulation of dynamic ecosystem service scenarios throughout the twenty-first century.The Jiulianshan National Nature Reserve in Jiangxi Province was considered as the study area.The results showed that ecosystem services and their synergistic effects will be optimized under scenarios that emphasize strict protection of ecological lands and incorporating the SSP1-2.6 scenario.However,sustaining optimized ecosystem services poses significant challenges in scenarios characterized by resource-intensive development and ongoing climate warming,as in the SSP5-8.5 scenario.Notably,discernible variations exist in balancing and synergizing the management of ecosystem services across diverse land uses and forest types.Our study underscores the importance of integrating vegetation response into the framework of ecosystem service forecasting,which is essential for assisting nature reserves in effectively addressing the multifaceted risks associated with climate change and rapid socio-economic development.
基金funded by Science and Technology Project of Hebei Education Department[QN2023085].
文摘Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantially enhance land resources.This study highlights the necessity for a precise correlation between land development initiatives and constraints in order to optimize efficiency and enhance the effectiveness of such projects,with the core being the seamless integration of land development engineering and techniques to eliminate agricultural constraints.This study employs a systems engineering approach to classify improvement factors into mobile and fixed categories,elucidating the integration methods of constraint factors.Adhering to the Wooden Barrel Principle,these constraints were rigorously analyzed based on soil quality,land topography,water availability,and agricultural infrastructure.An innovative method of engineering type combination is proposed,which effectively explains the correlation between natural factors combination,project type combination,and target factors combination.It provides a convenient way for the selection of barren grassland development projects and lays a foundation for land planning,development project establishment,program selection,engineering design,and budget preparation.Taking Tang County of China as an example,it is divided into 19 factor improvement areas,a quick reference table of engineering types is established,and 14 main types of engineering combinations are obtained,which lays a foundation for the application of theoretical framework in practice.
文摘Objective: To compare the functional outcomes of patients who had parotid masseter fascia reserved and unreserved flap elevating scheme in parotidectomy, especially the morbidity of Frey's syndrome. Methods: Twenty-three patients (group A) had parotid masseter fascia reserved in the parotidectomy, 32 patients (group B) had parotid masseter fascia unreserved in the operation. Compare the morbidity of gustatory sweating syndrome of the two groups. Results: Follow-up after 6 months to 2.5 years, gustatory sweating syndrome occurred in 4 patients of group A (17%), 17 patients in group B (57%). Conclusion: Reservation technic of the parotid masseter fascial in parotidectomy could prevent regeneration of parasympathetic nerve and thus prevent Frey's syndrome post-operation.
文摘This paper had described the influence of restoration and reservation of Xi'an Qujiang Pond Ruins Park on urban landscape with an emphasis,proposed to promote urban landscape development by making use of cultural ruins. It analyzed the good and bad effects of Xi'an Qujiang Pond Ruins Park on urban landscape and concluded that cultural ruins should be used to shape new outlook of urban landscape,so as to discuss the momentous significance of cultural ruins in urban landscape.
基金Supported by National Natural Science Fund (41075008)Chinese Meteorological Climate Changes Program (280200S011000)Gansu Meteorological Bureau Climate Science and Research Program(2011-09)~~
文摘[Objective] The aim was to explore the spatial and temporal distribution characteristics of wind energy resource and preservation in central and west area of Hexi Corridor. [Method] By dint of the wind speed data from 1955 to 2007 in ten meteorological observation station in central and west area of Hexi Corridor,and special wind tower fine data from January to December in 2007,the distribution and reserves of the region＇s wind energy resources were studied. [Result] The results showed that environmental wind speed was relatively stable in central and west Hexi Corridor. There were no distinct changes in climate characteristics distribution. There were regional differences in the distribution of wind energy,and there was a large numerical area of wind energy in Gazhou County and Yumen City; Wind energy in the region generally was higher. The wind energy density was above 100 w/m2 in the 10 m layer,around 140 w/m2 in most places,and was more than 200 w/m2 in the large number area. The wind grew in vertical direction along with the linear growth of height. Each 10 m high wind increased to 15 w/m2 averagely,50m layer wind energy was greater than the general 240 w/m2 and there were obvious changes on daily and annual with wind energy in central and west area of Hexi Corridor. The duration from March to May was a wind energy-intensive stage,10m height from the ground in the wind around 10：00 in low-value. After growing from 11：00,it met the day largest number at 18：00,and then reduced gradually. Effective wind speed hours in the region in general were more than 6 200 h,and the value in the large areas was close to 7 600 h. [Conclusion] The study laid basis for the development and application of wind energy in central and west area of Hexi Corridor.
文摘[Objective] The aim was to explore the effects of cultivation and seed reservation methods on quality and disease/insect damages of maca seed in cold highland areas,providing scientific references for cultivation and seed reservation and planning of maca vareity.[Method] Yellow,purple and black maca were selected and cultivated in the region with an elevation of 3 000 m to be experimental materials and cultivation and seed reservation methods were as follows：maca seed reservation in situ,seed reservation in original soils maca grown after selection of maca balls,and seed reservation in the region with an elevation of 2 700 m after selection of maca ball,seed reservation in greenhouses in the region with an elevation of 2 400 m after selection of maca ball,and growing selected balls in greenhouses and transplanting to the farmlands with an elevation of 2 400 m.[Result] The cultivation and seed reservation methods had significant or extremely significant effects on maca phenological phase;maca in different colors were treated by different cultivation and seed reservation methods,showing insignificant effects on disease and insect damages.[Conclusion] It can be concluded that the selected maca balls stored for 15 d as per the method grown in the region with an elevation of 2 700 m will improve seed quality and reduce disease or insect damages.
基金Supported by State Forestry Administration"Public Welfare Program"(201204205)~~
文摘[Objective] The aim is to conduct systematic diagnoses on the eco-vulnerability in Daqinggou National Natural Reserve. [Method] A kind of ＂problem pile＂ is proposed about 58 interrelated problems of ecological vulnerability by field survey and questionnaires and a ladder diagram of interrelations among the problems is established. The root problems, basic problems, core problems, interrelation and solving approaches are proposed, as well. [Result] It can be concluded from system diagnosis that fragile ecosystem of the Reserve can be observed from poor disasterresistibility, lower species diffusivity, lower system metabolism and poor system restorability. According to system diagnoses, management planning and control subsystem is key for protection of system vulnerability and solving different problems in process-oriented system. Conservation of the Reserve and ecological education on tourists are indispensible. It can be concluded from diagnoses that plant updating, evolution and ill growth in the Reserve are the focus of the vulnerable ecosystem, which influence species diffusivity, system metabolism and restorability and constitute central nodes of process-oriented and effect-oriented subsystems. [Conclusion] The research provides references for solving vulnerability issues of conservation and tourism management in Daqinggou National Nature Reserve.
文摘The concept of the brain cognitive reserve is derived from the well-acknowledged notion that the degree of brain damage does not always match the severity of clinical symptoms and neurological/cognitive outcomes.It has been suggested that the size of the brain(brain reserve) and the extent of neural connections acquired through life(neural reserve) set a threshold beyond which noticeable impairments occur.In contrast,cognitive reserve refers to the brain's ability to adapt and reo rganize stru cturally and functionally to resist damage and maintain function,including neural reserve and brain maintenance,resilience,and compensation(Verkhratsky and Zorec,2024).
文摘Located in southern Ningxia Hui Autonomous Region,northwest China,the Liupan Mountain National Nature Reserve covers a total area of 26,783.64 hectares.Established in 1982 and upgraded to national status in 1988,it protects a vital temperate mountainous forest ecosystem on the Loess Plateau.The reserve is centred around the Liupan Mountain range,one of China’s youngest mountain chains,formed by Himalayan tectonic movements.
文摘Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value of CT-FFR combined with CCTA–defined atherosclerotic extent in diabetic patients with coronary artery disease(CAD).Methods A retrospective pooled analysis of individual patient data was performed. Deep-learning-based vessel-specific CTFFR was calculated. All patients enrolled were followed-up for at least 5 years. Predictive abilities for major adverse cardiac events(MACE) were compared among three models(model 1), constructed using clinical variables;model 2, model 1+CCTA–derived atherosclerotic extent(Leiden risk score);and model 3, model 2+CT-FFR.Results A total of 480 diabetic patients [median age, 61(55–66) years;52.9% men] were included. During a median follow-up time of 2197(2126–2355) days, 55 patients(11.5%) experienced MACE. In multivariate-adjusted Cox models, Leiden risk score(HR: 1.06;95% CI: 1.01–1.11;P = 0.013) and CT-FFR ≤ 0.80(HR: 6.54;95% CI: 3.18–13.45;P < 0.001) were the independent predictors. The discriminant ability was higher in model 2 than in model 1(C-index, 0.75 vs. 0.63;P < 0.001) and was further promoted by adding CT-FFR to model 3(C-index, 0.81 vs. 0.75;P = 0.002). Net reclassification improvement(NRI) was 0.19(P = 0.009) for model 2 beyond model 1. Of note, adding CT-FFR to model 3 also exhibited significantly improved reclassification compared with model 2(NRI = 0.14;P = 0.011).Conclusion In diabetic patients with CAD, CT-FFR provides robust and incremental prognostic information for predicting longterm outcomes. The combined model exhibits improved prediction abilities, which is beneficial for risk stratification.
文摘CHINA Wuliangshan National Nature Reserve Spanning a significant altitudinal range from 1,600 to 3,371 metres and encompassing a total area of 31,585 hectares,the Wuliangshan National Nature Reserve protects one of the most intact and pristine forest ecosystems in southern Yunnan Province.
文摘Elk are seen at the Tian’ezhou National Nature Reserve for Elk in Shishou,Hubei Province,on 27 November 2025.The reserve’s elk population has risen from just 64 in the 1990s to more than 4,500 today.
基金project titled“Research on the Distribution Trend of Suitable Habitats for Terrestrial Wild Animals”(Number:SXBYKY2021029).
文摘Ungulates serve as key components in maintaining ecosystem stability,and their ecological functions are closely linked to the integrity of giant panda habitats within Wanglang National Nature Reserve.Assessment of ungulate habitat suitability in this reserve can provide critical insights into the distribution patterns of ungulate communities across protected areas while informing conservation strategy optimization.Therefore,six ungulate species were monitored,including Tufted deer(Elaphodus cephalophus),Chinese serow(Capricornis milneedwardsii),Chinese goral(Naemorhedus griseus),Sichuan takin(Budorcas taxicolor),Reeve's muntjac(Muntiacus reevesi),and Wild boar(Sus scrofa)in Wanglang National Nature Reserve.The infrared camera monitoring data(a total of 83 sites)and 23 environmental variables were collected from January 2011 to May 2019,the relative abundance index(RAI),independent samples t-test,and optimized MaxEnt model were employed to evaluate the habitat suitability of six ungulate species.Our findings were as follows:(1)there were significant differences in the annual RAI among the six ungulate species(P<0.01).(2)the suitable habitat area varied among species:Tufted deer occupied 9578 hm^(2)(31.08%of the total),Chinese serow 10,093 hm^(2)(32.75%);Chinese goral 9936 hm^(2)(32.24%);Sichuan takin 10,992 hm^(2)(35.67%);Reeve's muntjac 9542 hm^(2)(30.96%);and Wild boar 9642 hm^(2)(31.28%).(3)the spatial niche overlaps between each pair of the six ungulates were all relatively high(D=0.77-0.89).(4)the annual average temperature,precipitation during the coldest season,and vegetation were the key factors influencing habitat selection.These findings offer valuable references for the conservation of ungulates in natural reserve and are conducive to formulating more scientific and effective.
基金financially supported by the National Social Science Fund Key Projects of China(Grant No.23AZD086)。
文摘In recent years,the combined effects of seismic disturbances and extreme rainfall events have intensified water turbidity and sedimentation in several lakes within the Jiuzhaigou Nature Reserve located within the Jiuzhaigou watershed in Southwest China.In July 2024,turbidity events were observed in multiple core lakes,with noticeable impacts on local ecological functions and landscape values.To quantitatively characterize lake physical changes and explore their driving mechanisms,this study developed an integrated“air-space-ground”lake morphological measurement framework that combines unmanned aerial vehicle(UAV),unmanned surface vehicles(USV),and satellite remote sensing to enable high-precision acquisition of lake bathymetry,relationships between water level and surface area,and storage capacity.Additionally,time-series analyses of fractional vegetation cover(FVC)and the Revised Universal Soil Loss Equation(RUSLE)model were applied to characterize the patterns of change in vegetation cover and soil erosion intensity before and after seismic and extreme rainfall events.The results show that:(1)The physical morphology of the lakes has changed significantly compared with the field measurements conducted in 2004.The surface areas of the Arrow Bamboo Lake and the Rhinoceros Lake decreased by 15.2%~17.0%,and lake storage capacity decreased by 20%~33%.In Long Lake,the difference between the minimum and maximum daily water levels reached 13.21 m,and since 2021,the annual mean water level has exhibited a continuous decline at a rate of 1.46 m·a^(-1).(2)Based on the results of the FVC time series analysis,the two earthquake events resulted in decreases in vegetation cover by 19.14%and 13.19%,and these decreases were accompanied by enhanced soil erosion under heavy rainfall conditions.This process facilitated the transport of large amounts of terrestrial material into the lakes,thereby contributing to water turbidity and sediment accumulation.RUSLE-based estimates further indicate that the two earthquakes increased the peak mean soil erosion modulus by 7.61 t·ha^(-1)·a^(-1)and 4.10 t·ha^(-1)·a^(-1),respectively,relative to pre-earthquake conditions.Based on these findings,it is recommended to implement slope vegetation restoration on the upstream areas of the core lakes,strengthen slope protection in accident-prone locations,and monitor water-sediment dynamics during heavy rainfall periods,to mitigate sedimentation risks and enhance the stability of the scenic area's ecosystem.
文摘Objective:To identify predictors of pregnancy and live birth outcomes in assisted reproductive technology(ART)cycles based on patient characteristics,hormonal profile,and embryo transfer variables.Methods:This retrospective cohort study included 50 fresh in vitro fertilization(IVF)/intracytoplasmic sperm injection(ICSI)cycles selected from ART participants at a single tertiary ART center.Controlled ovarian stimulation was performed using recombinant follicle stimulating hormone(rFSH),gonadotropin-releasing hormone(GnRH)antagonist,and menotropins;oocyte retrieval occurred 36 h after trigger and embryo transfer was performed on day 3 or 5.Outcomes(chemical pregnancy,ongoing pregnancy,abortion,live birth)were compared across groups stratified by maternal age,antral follicle count(AFC),anti-Müllerian hormone(AMH),baseline luteinizing hormone(LH),estradiol(E2)at trigger,and endometrial thickness.Multivariate regression was used to identify independent predictors of live birth.Results:A total of 124 ART patients were screened during the study period,of whom 50 participants meeting the eligibility criteria were included in the final analysis.The median age of the participants was 35.8 years[interquartile range(IQR)32.5–39.6].The median AFC was 8(IQR 4–14),AMH level was 1.4 ng/mL(IQR 0.7–2.9),and the median endometrial thickness at embryo transfer was 10.2 mm(IQR 9.0–11.3).Chemical,ongoing,abortion,and live birth rates were 62%,32%,12%,and 16%,respectively.Younger maternal age(<35 years),higher AFC(>12),AMH 1–4 ng/mL,and endometrial thickness≥10 mm were associated with more favorable pregnancy outcomes.In multivariate analysis,higher baseline LH(β=0.089;95%CI 0.017–0.162;P=0.02)and greater endometrial thickness(β=0.145;95%CI 0.011–0.278;P=0.04)independently predicted live birth,whereas age,AFC,AMH,and E2 did not.Conclusions:Maternal age,ovarian reserve markers,LH levels,and endometrial thickness collectively influence ART outcomes.Baseline LH and endometrial receptivity are key independent predictors of live birth and may guide individualized treatment strategies.
