Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are in...Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are introduced first. Then two soft computational methods,genetic algorithms and back propagation (BP) neural network technology,are combined to the experiment on assisting in composing "two voice part inventions". The system presented in this paper is quite effective and satisfactory.展开更多
Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions ...Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.展开更多
BACKGROUND In patients with metastatic colorectal cancer,chemotherapy may lead to changes in body composition,including skeletal muscle quantity and quality,and body fat area and distribution.Longitudinal follow-up da...BACKGROUND In patients with metastatic colorectal cancer,chemotherapy may lead to changes in body composition,including skeletal muscle quantity and quality,and body fat area and distribution.Longitudinal follow-up data in a homogeneous population are required to understand these changes better.AIM To comprehensively evaluate changes in body composition and their prognostic value in patients with metastatic colorectal cancer undergoing palliative chemo-therapy.METHODS This retrospective study included patients with recurrent or metastatic colorectal cancer who received palliative chemotherapy between 2008 and 2017.Computed tomography scans were analyzed at multiple time points(before each new chemotherapy regimen and after discontinuing all chemotherapy).Body composition was analyzed from each scan using artificial intelligence software(AID-UTM,iAID Inc.),and its association with survival was evaluated through time-dependent Cox regression to adjust for time-varying effects.RESULTS This analysis included 1805 patients,with a median age at diagnosis of 57 years,and 62%were male.At first-line chemotherapy initiation,4.7%,30.9%,36.5%,and 37.1%of the patients had sarcopenia,myosteatosis,and visceral and subcutaneous obesity,respectively.During treatment,approximately 54.5%of the patients experienced significant changes in body composition,with 9.1%and 19.2%developing new sarcopenia and myosteatosis,respectively.Sarcopenia and myosteatosis were associated with poorer survival outcomes[hazard ratio(HR)for sarcopenia,2.55(95%CI:2.06-3.16,P<0.001;HR for myosteatosis,2.37(95%CI:2.00-2.82),P<0.001].In contrast,visceral and subcutaneous obesity were associated with improved survival[HR for visceral obesity,0.69(95%CI:0.57-0.82),P<0.001;HR for subcutaneous obesity,0.78(95%CI:0.64-0.95),P=0.015],with no negative impacts observed at higher fat levels.These changes correlated with end-of-life survival time.CONCLUSION Abnormalities and body composition changes were frequently observed during palliative chemotherapy for advanced colorectal cancer;myosteatosis was common.Comprehensive body composition assessment offers valuable prognostic insights without requiring additional testing.展开更多
Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CIN...Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CINAHL,and Web of Science were systematically searched for this network meta-analysis.Randomized controlled studies(RCTs)that included children aged 4-12 years with no physical or mental conditions;performed at least 1 type of lifestyle intervention;reported change in body mass index(BMI),BMI z-score,or body fat percentage(BFP);and were published between January2010 and August 2023 were included.Results:The final analysis included 91 RCTs with aggregate data for 58,649 children.All interventions were categorized into single-arm approaches(physical activity,diet,and behavioral and informational support)and combined arms approaches(bicomponent and multicomponent treatment).Multicomponent treatment showed significant effectiveness on the reduction of BMI(mean deviation(MD)-0.49,95%confidence interval(95%CI):-0.88 to-0.12),BMI z-score(MD=-0.11,95%CI:-0.18 to-0.04),and BFP(MD=-1.69,95%CI:-2.97 to-0.42)compared to the usual care condition.Bicomponent treatment also significantly reduced BMI(MD=-0.28,95%CI:-0.54 to-0.04)and BMI z-score(MD=-0.07,95%CI:-0.12 to-0.02)compared to usual care.Conclusion:Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP.Among single-component approaches,physical activity engagement emerged as the most effective.These findings should guide practitioners in recommending comprehensive lifestyle modifications for children.Moreover,children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.展开更多
A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most ...A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most existing erosion models assume that bed sediments are fully saturated,although this condition is rarely observed in nature.Therefore,a thorough understanding of debris flow overtopping erosion on a convex unsaturated bed is crucial for quantifying disaster risk.In this study,we experimentally investigated the effects of sediment composition,specifically coarse-grain size distribution and fine particle content,on the pore pressure evolution and entrainment of debris flows overriding a convex unsaturated colluvial bed.The average entrainment rate at convex sites for continuously graded bed sediment was higher than its discontinuous counterpart.The measured pore pressures within the unsaturated bed sediments were primarily generated by the passing debris flows.Furthermore,it was found that these pressures decreased as the fine particle content increased and the coarse-grain size of the erodible substrates decreased.When the coarse-grain size of the debris flow was smaller than that of the bed sediment,only a portion of the eroded material was entrained by the moving debris flow.In contrast,when the coarse-grain size of the debris flow was equal to or greater than that of the bed sediment,nearly all of the eroded material was entrained.The findings of this study could contribute to the assessment of hazard amplification and inform the design of mitigation and prevention strategies.展开更多
Understory plants are an integral part of forests,serving a variety of functions that help maintain healthy ecosystems.The structure and composition of the understory are influenced by numerous biotic and abiotic fact...Understory plants are an integral part of forests,serving a variety of functions that help maintain healthy ecosystems.The structure and composition of the understory are influenced by numerous biotic and abiotic factors,with light being critical.The introduction of the pathogen Cronartium ribicola,which causes white pine blister rust,into North America in the early 20 th century led to the near total loss of western white pine(Pinus monticola)from moist forests of the Northern Rockies.Management is reintroducing blister rust-resistant western white pine across the landscape,but the effects on the understory are unknown.We examined the effects of stand structure and proportion of western white pine in the overstory on understory diversity of vascular plants in closed canopy stands dominated by blister rust-resistant western white pine across northern Idaho.Habitat series explained the greatest amount of variation(34%)in species presence-absence,while canopy cover accounted for 25%,basal area of all trees for 18%,and the proportion of western white pine composition by 14%.Our analysis revealed positive relationships between the proportion of western white pine in the overstory and both the presence of understory plants and the cover of several understory species.For both the presence and cover,separate sets of thirteen species were found to have a positive relationship with the proportion of western white pine in the overstory,with eight species in common.This research fills a knowledge gap by using data from a range of stands across northern Idaho with varying abundance of western white pine in the overstory to evaluate the relationship between the understory and overstory composition.As land managers plant more western white pine trees,we are likely to see the concomitant increase in understory plant diversity across the landscape,in addition to numerous other benefits,including disturbance resistance and resilience.展开更多
Objective:Hypertension is a serious public health concern that is influenced by a variety of body composition parameters.This study examines the associations between body composition metrics and blood pressure(BP)in a...Objective:Hypertension is a serious public health concern that is influenced by a variety of body composition parameters.This study examines the associations between body composition metrics and blood pressure(BP)in a rural population,specifically how variations in body fat distribution and other metrics affect systolic blood pressure(SBP)and diastolic blood pressure(DBP).Methods:A cross-sectional study of 226 participants examined the relationships between body composition metrics—such as total body fat,visceral fat,and body mass index(BMI)—and BP.Correlation and regression analyses were used to assess these relationships.Results:The study found substantial positive correlations between visceral fat and total body fat with both SBP and DBP.Visceral fat was strongly connected with both SBP(r=0.145,P=0.030)and DBP(r=0.331,P<0.01),while total body fat was significantly correlated with DBP(r=0.268,P<0.01)but not SBP.Body composition variables explained 12.8% of the variance in SBP(R^(2)=0.128,P=0.001)and 15.0% in DBP(R^(2)=0.150,P<0.001).Conclusions:The study found substantial connections between body composition,particularly visceral and subcutaneous fat and systolic and DBP.Higher levels of visceral fat were linked to elevate BP.Body composition accounted for a significant amount of BP fluctuation.展开更多
Litter decomposition is an essential ecosystem process influenced by multiple factors,including substrate quality,climate,edaphic environment,and decomposer communities.However,the role of canopy species identity and ...Litter decomposition is an essential ecosystem process influenced by multiple factors,including substrate quality,climate,edaphic environment,and decomposer communities.However,the role of canopy species identity and diversity on leaf litter decomposition in forests remains understudied.By controlling for macroclimate,soil properties,and litter substrate in a mature common garden,we investigated whether a three-month tea bag incubation of standardized green and rooibos tea substrate is driven by canopy tree species characteristics and diversity.Our study hypothesized two primary pathways:a chemical engineering effect,where trees alter soil properties and decomposer communities through litter input,and a physical engineering effect,where tree canopy structure modulates the local microclimate.The results showed that even under uniform macroclimatic and initial soil conditions,mass loss rates varied widely for green tea(27.4%–73.2%)and rooibos tea(6.1%–34.7%),comparable as found in other research between distinct biomes.While substrate quality was the dominant factor,both engineering pathways and,to a minor extent,tree diversity modulated mass losses.For green tea,tree chemical and physical characteristics seemed equally important,while the physical environment showed an increased importance for rooibos.Incubation depth played a key role,where forest floor decomposition rates are more susceptible to temporal climate variations,and soil-layer decomposition rates are less susceptible to climate variations and more determined by tree species identity.Our findings suggest that tea bag experiments focusing solely on topsoil burial may underestimate processes in the forest floor and the mineralorganic boundary layer.This study underscores the critical role of litter substrate quality in decomposition while demonstrating that tree community composition and the associated herbaceous layer,through both chemical and physical engineering pathways,strongly modulate decomposition rates.展开更多
Panax notoginseng(P.notoginseng),a valuable traditional Chinese medicine,is the dried root of plants in Acanthopanax gracilistylus family,with the effect of dispersing blood stasis,eliminating swelling and relieving p...Panax notoginseng(P.notoginseng),a valuable traditional Chinese medicine,is the dried root of plants in Acanthopanax gracilistylus family,with the effect of dispersing blood stasis,eliminating swelling and relieving pain.With the development of modern medicine,the active ingredients and mechanisms of P.notoginseng have been gradually revealed.The present paper systematically reviews the chemical composition and biological activities of P.nologinseng,to provide a scientific basis and reference for detailed research on P.nologinseng.展开更多
This study proposes a multi-scale simplified residual convolutional neural network(MS-SRCNN)for the precise prediction of Mg-Nd binary alloy compositions from scanning electron microscope(SEM)images.A multi-scale data...This study proposes a multi-scale simplified residual convolutional neural network(MS-SRCNN)for the precise prediction of Mg-Nd binary alloy compositions from scanning electron microscope(SEM)images.A multi-scale data structure is established by spatially aligning and stacking SEM images at different magnifications.The MS-SRCNN significantly reduces computational runtime by over 90%compared to traditional architectures like ResNet50,VGG16,and VGG19,without compromising prediction accuracy.The model demonstrates more excellent predictive performance,achieving a>5%increase in R^(2) compared to single-scale models.Furthermore,the MS-SRCNN exhibits robust composition prediction capability across other Mg-based binary alloys,including Mg-La,Mg-Sn,Mg-Ce,Mg-Sm,Mg-Ag,and Mg-Y,thereby emphasizing its generalization and extrapolation potential.This research establishes a non-destructive,microstructure-informed composition analysis framework,reduces characterization time compared to traditional experiment methods and provides insights into the composition-microstructure relationship in diverse material systems.展开更多
Nail changes following upper extremity transplantation(UET)cannot be overlooked as they possess diagnostic and prognostic relevance in allotransplantation of upper limbs.This comprehensive review explores nail and nai...Nail changes following upper extremity transplantation(UET)cannot be overlooked as they possess diagnostic and prognostic relevance in allotransplantation of upper limbs.This comprehensive review explores nail and nail bed related changes encountered in UET recipients in the literature.The differential diagnosis of nail abnormalities in UET includes a wide range of systemic,local and iatrogenic conditions other than immune responses to the allograft.It requires interdisciplinary evaluation by primary transplant surgeons,pathologists,dermatologists and immunologists.The possible underlying mechanisms of nail pathology in UET and the management are discussed.It also underscores the importance of onychodystrophy and need for timely intervention and to improve outcomes in UET recipients.展开更多
The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process ...The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.展开更多
Cross-band camouflage technology is a critical necessity,enabling personnel and equipment to evade detection across evolving surveillance systems,thereby enhancing survivability and mission success.Herein,this work de...Cross-band camouflage technology is a critical necessity,enabling personnel and equipment to evade detection across evolving surveillance systems,thereby enhancing survivability and mission success.Herein,this work develops a layer-structured composite system based on carbon nanotube(CNT)film comprising ionic liquid(IL)interlayer for infrared(IR)modulation and surface-engineered Cu_(2)O nanoparticles for visible camouflage.The CNT/IL/CNT architecture enables reversible IR emissivity switching(Δε≈0.55)through electrically driven ion intercalation/deintercalation within 2 s,while spray-coated Cu_(2)O nanoparticles(100~400 nm diameter)on the top CNT film layer generate rich structure colors with 90%IR transmittance.This spectral-decoupling design overcomes the traditional trade-off between color visibility and IR transmittance observed in pigment-based systems.Remarkably,due to physical interface coupling,the Cu_(2)O-coated layer-structured system maintains exceptional electrical conductivity,enabling simultaneous electromagnetic interference shielding and electrothermal energy conversion.The integrated system demonstrates long-term operational stability.By unifying visible-IR camouflage,electromagnetic protection,and energy management in a lightweight platform,this work provides an important paradigm for cross-band camouflage technologies.展开更多
The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner M...The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.展开更多
Based on the idea of system,the paper had analyzed components of garden road system in urban park and their relations from the perspective of function,pattern and facility,and established framework of garden road syst...Based on the idea of system,the paper had analyzed components of garden road system in urban park and their relations from the perspective of function,pattern and facility,and established framework of garden road system for guidance of garden road construction.After introduction of the connotation of garden road system,its attributes were summarized which were isolated elements,integrated collection,clear level and dynamic development;and its functional composition had been concluded from the aspects of practical function and social function.Practical functions contained traffic organization and guidance tour,space division and landscape composition,facility organization and habitat improvement.Social functions consisted of communication and education function.The pattern of garden road system had been introduced in terms of pattern elements,level structure and layout form.Facilities of garden road system had been classified into five categories covering rest facilities,ornamental facilities,light facilities,display facilities and service facilities.展开更多
The inventories of nutrients in the surface water and large phytoplankton(>69 μm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for...The inventories of nutrients in the surface water and large phytoplankton(>69 μm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for N, P and from 1980s for Si. By examining long term changes of nutrient concentration, calculating stoichiometric balance, and comparing diatom composition, Si limitation of diatom production was found to be more possible. The possibility of Si limitation was from 37% in 1980s to 50% in 1990s. Jiaozhou Bay ecosystem is becoming serious eutrophication, with notable increase of NO 2 N, NO 3 N and NH 4 N from 0 1417 μmol/L, 0 5414 μmol/L, 1 7222 μmol/L in 1960s to 0 9551 μmol/L, 3 001 μmol/L, 8 0359 μmol/L in late 1990s respectively and prominent decrease of Si from 4 2614 μmol/L in 1980s to 1 5861 μmol/L in late 1990s; the nutrient structure is controlled by nitrogen; the main limiting nutrient is probably silicon; because of the Si limitation the phytoplankton community structure has changed drastically.展开更多
Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 day...Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight （SGRw） but did affect specific growth rate in terms of energy （SGRe）. Stocking density significantly influenced the ration level （RLw and RLe）, feed conversion ratio （FCRw and FCRe） and apparent digestibility rate （ADR）. Ration level and FCRw tended to increase with increasing density. Fish at the highest density D~ and lowest density D4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.展开更多
Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of ...Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of infinite volume of phase separator, ACR system with one phase separator is simulated in this paper. The variation of refrigerant composition under different valves opening is obtained. A related experimental system is set up to verify the variation. The result shows that when the valve opening connected to the evaporator increases or the valve opening under the phase separator decreases, the low-boiling component concentration of the working mixture passing through the compressor and condenser increases, while the high-boiling component concentration decreases. Furthermore, the variations of condensation pressure and evaporation pressure under different valves opening are also observed. This paper is helpful to deepen the understanding of ACR system.展开更多
Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,suc...Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,such effects under longterm straw incorporation conditions at different fertility levels are largely unknown.Thus,we conducted a 13-year ongoing experiment to evaluate the effects of long-term straw incorporation on the structure and functions of the soil food web in low and high fertility soils through analyzing its effects on nematode communities,food web indices and metabolic footprints.Four treatments were included:straw removal(–S)under non-fertilized(–NPK)or fertilized(+NPK)conditions;and straw incorporation(+S)under–NPK or+NPK conditions.Soil samples from a 0–20 cm depth layer were collected when wheat and rice were harvested.Compared with straw removal,straw incorporation increased the abundances of total nematodes,bacterivores,plant-parasites and omnivores-predators,as well the relative abundances of omnivores-predators with increases of 73.06,89.29,95.31,238.98,and 114.61%in–NPK soils and 16.23,2.23,19.01,141.38,and 90.23%in+NPK soils,respectively.Regardless of sampling times and fertilization effects,straw incorporation increased the diversity and community stability of nematodes,as indicated by the Shannon-Weaver diversity index and maturity index.Enrichment and structure index did not show significant responses to straw incorporation,but a slight increase was observed in the structure index.The analysis of nematode metabolic footprints showed that straw incorporation increased the plant-parasite footprint and structure footprint by 97.27 and 305.39%in–NPK soils and by 11.29 and 149.56%in+NPK soils,but did not significantly influence enrichment,bacterivore and fungivore footprints.In conclusion,long-term straw incorporation,particularly under a low fertility level,favored the soil nematodes and regulated the soil food web mainly via a top-down effect.展开更多
This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined s...This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined seventh stage of Cambrian System at the first appearance of the cosmopolitan agnostoid Lejopyge iaevigata. This level is favored in a vote of International Subcommission on Cambrian Stratigraphy （ISCS） as the biohorizon for defining the base of a global stage. Two hundred and sixty-four samples for carbon and oxygen isotope analysis have been collected from the carbonate successions at an interval of 0.25 to 0.5 m in this section. Results of the carbon isotope data exhibit a remarkable disciplinarian trend. The pattern of the carbon isotope evolution is gently undulant with a relatively long period during the underlying Drumian Stage, and then the values of δ13C fluctuate sharply with a short period in provisional seventh stage. The onset of sharp fluctuation in the δ13C values begins at the proposed GSSP level, defining the base of the global seventh stage, where δ13C values change from a gentle trend to a sharp trend. Distinct covariant-relationships among δ13C,δ18O, and sea level fluctuations suggest that a warming change in paleoclimate took place during the early global seventh stage, which led to a positive shift in δ13C values.展开更多
基金National Natural Science Foundation of China (No.60975076)
文摘Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are introduced first. Then two soft computational methods,genetic algorithms and back propagation (BP) neural network technology,are combined to the experiment on assisting in composing "two voice part inventions". The system presented in this paper is quite effective and satisfactory.
基金supported by the Fundamental Research Funds of Chinese Academy of Forestry(Nos.CAFYBB2022SY037,CAFYBB2021ZA002 and CAFYBB2022QC002)the Basic Research Foundation of Yunnan Province(Grant No.202201AT070264).
文摘Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.
基金Supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute,by the Ministry of Health&Welfare,Republic of Korea,No.RS-2018-KH049509the 2022 Cancer Research Support Project from the Korea Foundation for Cancer Research,No.CB-2022-A-3.
文摘BACKGROUND In patients with metastatic colorectal cancer,chemotherapy may lead to changes in body composition,including skeletal muscle quantity and quality,and body fat area and distribution.Longitudinal follow-up data in a homogeneous population are required to understand these changes better.AIM To comprehensively evaluate changes in body composition and their prognostic value in patients with metastatic colorectal cancer undergoing palliative chemo-therapy.METHODS This retrospective study included patients with recurrent or metastatic colorectal cancer who received palliative chemotherapy between 2008 and 2017.Computed tomography scans were analyzed at multiple time points(before each new chemotherapy regimen and after discontinuing all chemotherapy).Body composition was analyzed from each scan using artificial intelligence software(AID-UTM,iAID Inc.),and its association with survival was evaluated through time-dependent Cox regression to adjust for time-varying effects.RESULTS This analysis included 1805 patients,with a median age at diagnosis of 57 years,and 62%were male.At first-line chemotherapy initiation,4.7%,30.9%,36.5%,and 37.1%of the patients had sarcopenia,myosteatosis,and visceral and subcutaneous obesity,respectively.During treatment,approximately 54.5%of the patients experienced significant changes in body composition,with 9.1%and 19.2%developing new sarcopenia and myosteatosis,respectively.Sarcopenia and myosteatosis were associated with poorer survival outcomes[hazard ratio(HR)for sarcopenia,2.55(95%CI:2.06-3.16,P<0.001;HR for myosteatosis,2.37(95%CI:2.00-2.82),P<0.001].In contrast,visceral and subcutaneous obesity were associated with improved survival[HR for visceral obesity,0.69(95%CI:0.57-0.82),P<0.001;HR for subcutaneous obesity,0.78(95%CI:0.64-0.95),P=0.015],with no negative impacts observed at higher fat levels.These changes correlated with end-of-life survival time.CONCLUSION Abnormalities and body composition changes were frequently observed during palliative chemotherapy for advanced colorectal cancer;myosteatosis was common.Comprehensive body composition assessment offers valuable prognostic insights without requiring additional testing.
文摘Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CINAHL,and Web of Science were systematically searched for this network meta-analysis.Randomized controlled studies(RCTs)that included children aged 4-12 years with no physical or mental conditions;performed at least 1 type of lifestyle intervention;reported change in body mass index(BMI),BMI z-score,or body fat percentage(BFP);and were published between January2010 and August 2023 were included.Results:The final analysis included 91 RCTs with aggregate data for 58,649 children.All interventions were categorized into single-arm approaches(physical activity,diet,and behavioral and informational support)and combined arms approaches(bicomponent and multicomponent treatment).Multicomponent treatment showed significant effectiveness on the reduction of BMI(mean deviation(MD)-0.49,95%confidence interval(95%CI):-0.88 to-0.12),BMI z-score(MD=-0.11,95%CI:-0.18 to-0.04),and BFP(MD=-1.69,95%CI:-2.97 to-0.42)compared to the usual care condition.Bicomponent treatment also significantly reduced BMI(MD=-0.28,95%CI:-0.54 to-0.04)and BMI z-score(MD=-0.07,95%CI:-0.12 to-0.02)compared to usual care.Conclusion:Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP.Among single-component approaches,physical activity engagement emerged as the most effective.These findings should guide practitioners in recommending comprehensive lifestyle modifications for children.Moreover,children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1505205)the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-01)Sichuan Science and Technology Program(Grant No.2024NSFSC0781).
文摘A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most existing erosion models assume that bed sediments are fully saturated,although this condition is rarely observed in nature.Therefore,a thorough understanding of debris flow overtopping erosion on a convex unsaturated bed is crucial for quantifying disaster risk.In this study,we experimentally investigated the effects of sediment composition,specifically coarse-grain size distribution and fine particle content,on the pore pressure evolution and entrainment of debris flows overriding a convex unsaturated colluvial bed.The average entrainment rate at convex sites for continuously graded bed sediment was higher than its discontinuous counterpart.The measured pore pressures within the unsaturated bed sediments were primarily generated by the passing debris flows.Furthermore,it was found that these pressures decreased as the fine particle content increased and the coarse-grain size of the erodible substrates decreased.When the coarse-grain size of the debris flow was smaller than that of the bed sediment,only a portion of the eroded material was entrained by the moving debris flow.In contrast,when the coarse-grain size of the debris flow was equal to or greater than that of the bed sediment,nearly all of the eroded material was entrained.The findings of this study could contribute to the assessment of hazard amplification and inform the design of mitigation and prevention strategies.
基金supported by the United States Department of Agriculture,Forest Service,Rocky Mountain Research Station through Research Joint Venture Agreement 17–098Funding was provided by the USDA Forest Service Northern Region。
文摘Understory plants are an integral part of forests,serving a variety of functions that help maintain healthy ecosystems.The structure and composition of the understory are influenced by numerous biotic and abiotic factors,with light being critical.The introduction of the pathogen Cronartium ribicola,which causes white pine blister rust,into North America in the early 20 th century led to the near total loss of western white pine(Pinus monticola)from moist forests of the Northern Rockies.Management is reintroducing blister rust-resistant western white pine across the landscape,but the effects on the understory are unknown.We examined the effects of stand structure and proportion of western white pine in the overstory on understory diversity of vascular plants in closed canopy stands dominated by blister rust-resistant western white pine across northern Idaho.Habitat series explained the greatest amount of variation(34%)in species presence-absence,while canopy cover accounted for 25%,basal area of all trees for 18%,and the proportion of western white pine composition by 14%.Our analysis revealed positive relationships between the proportion of western white pine in the overstory and both the presence of understory plants and the cover of several understory species.For both the presence and cover,separate sets of thirteen species were found to have a positive relationship with the proportion of western white pine in the overstory,with eight species in common.This research fills a knowledge gap by using data from a range of stands across northern Idaho with varying abundance of western white pine in the overstory to evaluate the relationship between the understory and overstory composition.As land managers plant more western white pine trees,we are likely to see the concomitant increase in understory plant diversity across the landscape,in addition to numerous other benefits,including disturbance resistance and resilience.
基金supported by Universitas Advent Indonesia(No.067/EKS-SU/V/24 and 389/KEPK-FIK.UNAI/EC/V/24)。
文摘Objective:Hypertension is a serious public health concern that is influenced by a variety of body composition parameters.This study examines the associations between body composition metrics and blood pressure(BP)in a rural population,specifically how variations in body fat distribution and other metrics affect systolic blood pressure(SBP)and diastolic blood pressure(DBP).Methods:A cross-sectional study of 226 participants examined the relationships between body composition metrics—such as total body fat,visceral fat,and body mass index(BMI)—and BP.Correlation and regression analyses were used to assess these relationships.Results:The study found substantial positive correlations between visceral fat and total body fat with both SBP and DBP.Visceral fat was strongly connected with both SBP(r=0.145,P=0.030)and DBP(r=0.331,P<0.01),while total body fat was significantly correlated with DBP(r=0.268,P<0.01)but not SBP.Body composition variables explained 12.8% of the variance in SBP(R^(2)=0.128,P=0.001)and 15.0% in DBP(R^(2)=0.150,P<0.001).Conclusions:The study found substantial connections between body composition,particularly visceral and subcutaneous fat and systolic and DBP.Higher levels of visceral fat were linked to elevate BP.Body composition accounted for a significant amount of BP fluctuation.
基金funded by the Global PhD Scholarship between KU Leuven and UCLouvain。
文摘Litter decomposition is an essential ecosystem process influenced by multiple factors,including substrate quality,climate,edaphic environment,and decomposer communities.However,the role of canopy species identity and diversity on leaf litter decomposition in forests remains understudied.By controlling for macroclimate,soil properties,and litter substrate in a mature common garden,we investigated whether a three-month tea bag incubation of standardized green and rooibos tea substrate is driven by canopy tree species characteristics and diversity.Our study hypothesized two primary pathways:a chemical engineering effect,where trees alter soil properties and decomposer communities through litter input,and a physical engineering effect,where tree canopy structure modulates the local microclimate.The results showed that even under uniform macroclimatic and initial soil conditions,mass loss rates varied widely for green tea(27.4%–73.2%)and rooibos tea(6.1%–34.7%),comparable as found in other research between distinct biomes.While substrate quality was the dominant factor,both engineering pathways and,to a minor extent,tree diversity modulated mass losses.For green tea,tree chemical and physical characteristics seemed equally important,while the physical environment showed an increased importance for rooibos.Incubation depth played a key role,where forest floor decomposition rates are more susceptible to temporal climate variations,and soil-layer decomposition rates are less susceptible to climate variations and more determined by tree species identity.Our findings suggest that tea bag experiments focusing solely on topsoil burial may underestimate processes in the forest floor and the mineralorganic boundary layer.This study underscores the critical role of litter substrate quality in decomposition while demonstrating that tree community composition and the associated herbaceous layer,through both chemical and physical engineering pathways,strongly modulate decomposition rates.
文摘Panax notoginseng(P.notoginseng),a valuable traditional Chinese medicine,is the dried root of plants in Acanthopanax gracilistylus family,with the effect of dispersing blood stasis,eliminating swelling and relieving pain.With the development of modern medicine,the active ingredients and mechanisms of P.notoginseng have been gradually revealed.The present paper systematically reviews the chemical composition and biological activities of P.nologinseng,to provide a scientific basis and reference for detailed research on P.nologinseng.
基金funded by the National Natural Science Foundation of China(No.52204407)the Natural Science Foundation of Jiangsu Province(No.BK20220595)the China Postdoctoral Science Foundation(No.2022M723689).
文摘This study proposes a multi-scale simplified residual convolutional neural network(MS-SRCNN)for the precise prediction of Mg-Nd binary alloy compositions from scanning electron microscope(SEM)images.A multi-scale data structure is established by spatially aligning and stacking SEM images at different magnifications.The MS-SRCNN significantly reduces computational runtime by over 90%compared to traditional architectures like ResNet50,VGG16,and VGG19,without compromising prediction accuracy.The model demonstrates more excellent predictive performance,achieving a>5%increase in R^(2) compared to single-scale models.Furthermore,the MS-SRCNN exhibits robust composition prediction capability across other Mg-based binary alloys,including Mg-La,Mg-Sn,Mg-Ce,Mg-Sm,Mg-Ag,and Mg-Y,thereby emphasizing its generalization and extrapolation potential.This research establishes a non-destructive,microstructure-informed composition analysis framework,reduces characterization time compared to traditional experiment methods and provides insights into the composition-microstructure relationship in diverse material systems.
文摘Nail changes following upper extremity transplantation(UET)cannot be overlooked as they possess diagnostic and prognostic relevance in allotransplantation of upper limbs.This comprehensive review explores nail and nail bed related changes encountered in UET recipients in the literature.The differential diagnosis of nail abnormalities in UET includes a wide range of systemic,local and iatrogenic conditions other than immune responses to the allograft.It requires interdisciplinary evaluation by primary transplant surgeons,pathologists,dermatologists and immunologists.The possible underlying mechanisms of nail pathology in UET and the management are discussed.It also underscores the importance of onychodystrophy and need for timely intervention and to improve outcomes in UET recipients.
基金support of the Korea Institute of Industrial Technol-ogy as“Development of a remote manufacturing system for high-risk,high-difficulty pipe production processes”(kitech EH-25-0004)supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(RS-2023–00237714+2 种基金Development of Dynamic Metrology Tool for CMP Process StabilizationRS-2025–02634755Development of Real-Time Electrical Fire Prevention System Technology Reflecting the Characteristics of Traditional Markets)funded by the Ministry of Trade,Industry&Energy(MOTIE,Republic of Korea).
文摘The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.
基金Financial support from the National Nature Science Foundation of China(No.:52373244)the Foundation of National Science and Technology Key Laboratory(No.:KZ571801)。
文摘Cross-band camouflage technology is a critical necessity,enabling personnel and equipment to evade detection across evolving surveillance systems,thereby enhancing survivability and mission success.Herein,this work develops a layer-structured composite system based on carbon nanotube(CNT)film comprising ionic liquid(IL)interlayer for infrared(IR)modulation and surface-engineered Cu_(2)O nanoparticles for visible camouflage.The CNT/IL/CNT architecture enables reversible IR emissivity switching(Δε≈0.55)through electrically driven ion intercalation/deintercalation within 2 s,while spray-coated Cu_(2)O nanoparticles(100~400 nm diameter)on the top CNT film layer generate rich structure colors with 90%IR transmittance.This spectral-decoupling design overcomes the traditional trade-off between color visibility and IR transmittance observed in pigment-based systems.Remarkably,due to physical interface coupling,the Cu_(2)O-coated layer-structured system maintains exceptional electrical conductivity,enabling simultaneous electromagnetic interference shielding and electrothermal energy conversion.The integrated system demonstrates long-term operational stability.By unifying visible-IR camouflage,electromagnetic protection,and energy management in a lightweight platform,this work provides an important paradigm for cross-band camouflage technologies.
文摘The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.
基金Supported by Fund Project of Scientific Research of Zhongkai University of Agriculture and Engineering(G3071201)~~
文摘Based on the idea of system,the paper had analyzed components of garden road system in urban park and their relations from the perspective of function,pattern and facility,and established framework of garden road system for guidance of garden road construction.After introduction of the connotation of garden road system,its attributes were summarized which were isolated elements,integrated collection,clear level and dynamic development;and its functional composition had been concluded from the aspects of practical function and social function.Practical functions contained traffic organization and guidance tour,space division and landscape composition,facility organization and habitat improvement.Social functions consisted of communication and education function.The pattern of garden road system had been introduced in terms of pattern elements,level structure and layout form.Facilities of garden road system had been classified into five categories covering rest facilities,ornamental facilities,light facilities,display facilities and service facilities.
文摘The inventories of nutrients in the surface water and large phytoplankton(>69 μm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for N, P and from 1980s for Si. By examining long term changes of nutrient concentration, calculating stoichiometric balance, and comparing diatom composition, Si limitation of diatom production was found to be more possible. The possibility of Si limitation was from 37% in 1980s to 50% in 1990s. Jiaozhou Bay ecosystem is becoming serious eutrophication, with notable increase of NO 2 N, NO 3 N and NH 4 N from 0 1417 μmol/L, 0 5414 μmol/L, 1 7222 μmol/L in 1960s to 0 9551 μmol/L, 3 001 μmol/L, 8 0359 μmol/L in late 1990s respectively and prominent decrease of Si from 4 2614 μmol/L in 1980s to 1 5861 μmol/L in late 1990s; the nutrient structure is controlled by nitrogen; the main limiting nutrient is probably silicon; because of the Si limitation the phytoplankton community structure has changed drastically.
基金Supported by the National Natural Science Foundation of China(No.31240012)the Earmarked Fund for Modern Agro-industry Technology Research System+2 种基金the Special Foundation for Postdoctoral Innovative Projects of Shandong Province(No.201101009)the National Key Technology R&D Program of China(No.2011BAD13B04)The Key Laboratory of Mariculture(KLM),Ministry of Education,Ocean University of China(OUC)
文摘Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight （SGRw） but did affect specific growth rate in terms of energy （SGRe）. Stocking density significantly influenced the ration level （RLw and RLe）, feed conversion ratio （FCRw and FCRe） and apparent digestibility rate （ADR）. Ration level and FCRw tended to increase with increasing density. Fish at the highest density D~ and lowest density D4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.
基金Supported by the China Postdoctoral Science Foundation(2014M552195)the State Key Laboratory Foundation of Subtropical Building,South China University of Technology(2013ZC13)the Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization,South China University of Technology(2013A061401005)
文摘Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of infinite volume of phase separator, ACR system with one phase separator is simulated in this paper. The variation of refrigerant composition under different valves opening is obtained. A related experimental system is set up to verify the variation. The result shows that when the valve opening connected to the evaporator increases or the valve opening under the phase separator decreases, the low-boiling component concentration of the working mixture passing through the compressor and condenser increases, while the high-boiling component concentration decreases. Furthermore, the variations of condensation pressure and evaporation pressure under different valves opening are also observed. This paper is helpful to deepen the understanding of ACR system.
基金This study was funded by the Open Project of Key Laboratory of the Ministry of Agriculture and Rural Affairs,China(KLFAW201705)the National Natural Science Foundation of China(31870501)+1 种基金the Technological Achievements Cultivation Project of Hubei Academy of Agricultural Sciences(2017CGPY01)the Key Project of Technological Innovation in Hubei Province,China(2018ABA091).
文摘Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,such effects under longterm straw incorporation conditions at different fertility levels are largely unknown.Thus,we conducted a 13-year ongoing experiment to evaluate the effects of long-term straw incorporation on the structure and functions of the soil food web in low and high fertility soils through analyzing its effects on nematode communities,food web indices and metabolic footprints.Four treatments were included:straw removal(–S)under non-fertilized(–NPK)or fertilized(+NPK)conditions;and straw incorporation(+S)under–NPK or+NPK conditions.Soil samples from a 0–20 cm depth layer were collected when wheat and rice were harvested.Compared with straw removal,straw incorporation increased the abundances of total nematodes,bacterivores,plant-parasites and omnivores-predators,as well the relative abundances of omnivores-predators with increases of 73.06,89.29,95.31,238.98,and 114.61%in–NPK soils and 16.23,2.23,19.01,141.38,and 90.23%in+NPK soils,respectively.Regardless of sampling times and fertilization effects,straw incorporation increased the diversity and community stability of nematodes,as indicated by the Shannon-Weaver diversity index and maturity index.Enrichment and structure index did not show significant responses to straw incorporation,but a slight increase was observed in the structure index.The analysis of nematode metabolic footprints showed that straw incorporation increased the plant-parasite footprint and structure footprint by 97.27 and 305.39%in–NPK soils and by 11.29 and 149.56%in+NPK soils,but did not significantly influence enrichment,bacterivore and fungivore footprints.In conclusion,long-term straw incorporation,particularly under a low fertility level,favored the soil nematodes and regulated the soil food web mainly via a top-down effect.
基金the National Natural Science Foundation of China (Nos. 40672023, 40332018)Chinese Academy of Sciences (KZCX2-YW-122) and the Major Basic Research Project of MST (2006CB806400).
文摘This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined seventh stage of Cambrian System at the first appearance of the cosmopolitan agnostoid Lejopyge iaevigata. This level is favored in a vote of International Subcommission on Cambrian Stratigraphy （ISCS） as the biohorizon for defining the base of a global stage. Two hundred and sixty-four samples for carbon and oxygen isotope analysis have been collected from the carbonate successions at an interval of 0.25 to 0.5 m in this section. Results of the carbon isotope data exhibit a remarkable disciplinarian trend. The pattern of the carbon isotope evolution is gently undulant with a relatively long period during the underlying Drumian Stage, and then the values of δ13C fluctuate sharply with a short period in provisional seventh stage. The onset of sharp fluctuation in the δ13C values begins at the proposed GSSP level, defining the base of the global seventh stage, where δ13C values change from a gentle trend to a sharp trend. Distinct covariant-relationships among δ13C,δ18O, and sea level fluctuations suggest that a warming change in paleoclimate took place during the early global seventh stage, which led to a positive shift in δ13C values.
