As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study...As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study,it is revealed that the intensity of the SPCZ can change the characteristics of sea ice in the West Antarctica during austral autumn,which is significantly independent of the El Niño-Southern Oscillation(ENSO).Observational and numerical results suggest that a stronger-than-usual SPCZ can generate a poleward-propagating Rossby wave train along a great circular route and induce a weakening of the Amundsen Sea Low(ASL)near West Antarctica,which may somewhat offset the teleconnections exerted by ENSO.These changes in the strength and zonal extent of ASL is noticeable and robustly lead to a tripole response of sea-ice perturbations in the Ross,Amundsen,and Weddell Seas.We find that the wind-driven dynamical processes determine the local sea-ice changes,while the influence from thermodynamic processes is trivial.This research underscores the need to consider the SPCZ variability for a comprehensive understanding of sea-ice changes in West Antarctica on interannual timescales.展开更多
As a geopolitical bloc,the West is suffering unprecedented shocks.Once shared values are beginning to collapse,the shared security concept is rapidly diverging,and the shared view of order is also tending to disintegr...As a geopolitical bloc,the West is suffering unprecedented shocks.Once shared values are beginning to collapse,the shared security concept is rapidly diverging,and the shared view of order is also tending to disintegrate.There are more and more claims in the world,especially within the West,that the West has come to an end.Whether the West has ended or is heading toward its end is still a matter of opinion.However,it is undeniable that major problems have emerged within the West and some fundamental changes have taken place.Moreover,due to their structural reasons,these changes are not temporary and are likely to be a long-term trend.The West has long played an important role in many areas such as international politics,economy,and security.Its major changes will inevitably have a profound impact on the world order.The West will be further divided,and the opposition and confrontation between the West and non-West may tend to fade.The multipolarization of the world and the democratization of international relations will accelerate.展开更多
Key West is in the state of Florida.It is the southernmost city in the USA.That means it is the city farthest to the south.It is very close to Cuba,another country.
Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly infl...Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.展开更多
The West Lake area and water system in West Lake scenic area of Hangzhou City directly affect the soil properties of waterfront lawn beds,which in turn have a significant impact on the growth of waterfront lawns.In or...The West Lake area and water system in West Lake scenic area of Hangzhou City directly affect the soil properties of waterfront lawn beds,which in turn have a significant impact on the growth of waterfront lawns.In order to further improve the quality of lawns,the conditions of 10 waterfront lawn beds in West Lake scenic area were tested and analyzed.The results showed that the waterfront lawn beds in West Lake scenic area were prone to salinization,with moderate or high pH values,moderate overall organic matter content,relatively sufficient nitrogen and phosphorus elements,and relatively deficient potassium elements.The contents of exchangeable calcium in all samples were higher than the lower limit,and the contents of exchangeable sodium,exchangeable magnesium,and available manganese in the soil were moderate or low,while the contents of available copper were moderate or high.展开更多
Understanding the formation of lithium-rich pegmatites is critical for meeting global lithium demand.The 509 Daobanxi Li pegmatite deposit,located in the West Kunlun orogenic belt of northwestern China,represents a si...Understanding the formation of lithium-rich pegmatites is critical for meeting global lithium demand.The 509 Daobanxi Li pegmatite deposit,located in the West Kunlun orogenic belt of northwestern China,represents a significant example of an LCT-type(Li-Cs-Ta)pegmatite system.This study investigates the paragenetic sequence of lithium(Li)minerals and the factors controlling their crystallization,providing new insights into the magmatic-hydrothermal evolution of rare-element pegmatites.Pegmatite dikes exhibit distinct zonation,comprising a wall rock zone,a border zone(aplitic layer),and a core zone(pegmatitic layer),with Li mineralization concentrated in the pegmatitic and aplitic layers.The primary Li minerals include spodumene(Spd),montebrasite(Mbs),eucryptite(Ecr),elbaite(Elb),and lepidolite(Lpd),which crystallize in the order of spodumene→montebrasite→elbaite→lepidolite.Spodumene,the dominant Li-bearing mineral,crystallizes from a Li-saturated melt during the magmatic stage.Montebrasite,a Li-phosphate mineral,forms in P-rich environments,coexisting with spodumene and columbite-group minerals(CGM).During the magmatic-hydrothermal transition,elbaite crystallizes from a B-rich melt,exhibiting skeletal and patchy zoning due to undercooling and disequilibrium crystallization.Hydrothermal alteration leads to the breakdown of spodumene and the formation of secondary minerals such as eucryptite and lepidolite,with lepidolite being the final Li-bearing phase,enriched in fluorine.The coupled dissolution-precipitation processes during the magmatic-hydrothermal transition play a critical role in the remobilization and enrichment of rare elements such as Li,Nb,Ta,and Sn.This deposit,characterized by spodumene crystallization in the Spd+Quartz stability field(≥300 MPa,≤725℃)and subsequent alteration to Ecr+quartz assemblages(<270℃,<160 MPa),exhibits broader temperature-pressure conditions exceeding typical global pegmatites like Tanco,with no petalite formation observed due to its persistent exclusion from petalite stability fields throughout mineralization.The shear zone controls the pegmatite emplacement and lithium enrichment in the 509 Daobanxi lithium deposit,and its deformation-fluid coupling mechanism provides new insights for the exploration of LCT pegmatite deposits.The present study highlights the importance of understanding both magmatic and hydrothermal processes in the formation of LCT-type pegmatites and provides valuable insights for the exploration of critical metal resources in similar geological settings.展开更多
The subduction and closure history of the Paleo-Tethyan Ocean is of significant importance to the formation of the Alpine-Himalayan orogenic belt.However,in West Qinling,China,the evolution of the subducted Paleo-Teth...The subduction and closure history of the Paleo-Tethyan Ocean is of significant importance to the formation of the Alpine-Himalayan orogenic belt.However,in West Qinling,China,the evolution of the subducted Paleo-Tethyan oceanic slab in the mantle remains unclear.In this work,we determine high-resolution P-wave azimuthal anisotropic tomography of the crust and upper mantle beneath west Qinling by inverting newly collected local and teleseismic data.The local earthquakes are relocated by jointly using permanent and portable stations and weighted by their hypocentral errors during the inversion.Our model reveals a slab-like high P-wave velocity(V_(p))anomaly below 300 km depth and significant depth variations of anisotropy in the upper mantle beneath the West Qinling orogen.By comparing with previous geophysical results and integrating with geological and geochemical findings,we interpret that this high-V_(p)anomaly is most likely the subducted Mianlue oceanic slab preserved in the upper mantle and the mantle transition zone since the early Mesozoic.Beneath the Songpan-Ganzi block and the Longzhong basin,low-V anomalies with weak azimuthal anisotropy suggest a vertical mantle upwelling at a depth of 120 to 200 km,providing positive buoyancy to the subducted oceanic slab and extends its stagnation duration in the upper mantle.展开更多
The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents ...The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents a sustainable strategy to mitigate lignocellulosic waste,reduce reliance on fossil resources,and lower environmental pollution.This approach also creates economic opportunities for rural African communities by generating diverse income sources for workers in collection,processing,and manufacturing.As a result,the integration of agricultural residues into biocomposites production not only addresses environmental concerns but also fosters economic growth and supports rural development.In this review,five biomasses from West Africa are examined,focusing on their production,chemical composition,physical and mechanical properties,and potential applications in biocomposites.The five biomasses listed are cocoa pod husks,oil palm empty fruit bunches,rice husks,millet stalks,and typha stalks.Key parameters,such as the type of binder,fiber dimensions,fiber-to-binder ratio,and the strength of fiber-binder adhesion,are systematically studied to assess their influence on the overall performance of the resulting composites.Special attention is given to understanding how these factors affect mechanical properties(e.g.,strength and flexibility),thermal behavior(e.g.,insulation capacity and heat resistance),and physico-chemical characteristics(e.g.,moisture absorption,density,and chemical stability).This comprehensive analysis provides insights into optimizing composite formulations for enhanced functionality and sustainability.This study is essential to optimize the use of agricultural residues inWest Africa for biocomposites,tackling waste issues,promoting sustainability,and filling research gaps on their properties.展开更多
Subduction initiation is a critical part of the plate tectonic system,but its geodynamic process is still poorly understood due to the lack of well-preserved geological records.Based on new zircon U–Pb–Hf isotopic a...Subduction initiation is a critical part of the plate tectonic system,but its geodynamic process is still poorly understood due to the lack of well-preserved geological records.Based on new zircon U–Pb–Hf isotopic and whole-rock geochemical data,we report the first discovery of a latest Cambrian–Early Ordovician forearc-arc rock sequence in the Eastern Alps.This sequence includes granitic gneisses,amphibolites,and amphibole plagiogneisses from the ophiolitic Speik Complex and Gleinalpe Complex.These rocks exhibit geochemical affinities with typical oceanic plagiogranites,forearc basalts(FABs),and island arc basalts,respectively.The latest Cambrian plagiogranitic protoliths(491±2 Ma)are shearing-type plagiogranites that were formed in the tectonic setting of forearc spreading.The latest Cambrian FABs(496–489 Ma)have similar geochemical compositions and positiveεHf(t)values(+2.5 to+14.9)to the depleted mid-ocean ridge basalts.However,they show depletion in high field strength elements(HFSEs;e.g.,Nb,Ta,and Zr)and have relatively low Ti/V ratios.These features suggest that they were derived from a depleted mantle source modified by subducting slab-released components in a forearc environment.The Early Ordovician basaltic protoliths(476–472 Ma)of amphibole plagiogneisses show enrichment in large ion lithophile elements and depletion in HFSEs(e.g.Nb,Ta,Zr,and Hf),implying a mature island arc environment.These metaigneous rocks,along with the coeval boninite-like high-Mg amphibolites near the study area,form a typical rock sequence resembling that of the Izu–Bonin–Mariana(IBM)arc system.The Speik and Gleinalpe complexes document a complete magmatic evolution from subduction initiation to mature arc development within the West Proto-Tethys Ocean.Integrating our new data with published work,we reconstruct the late Ediacaran–early Paleozoic tectonic evolution of the northern Gondwana.During the late Ediacaran–early Cambrian,the rollback of the West Proto-Tethys oceanic plate triggered the separation of the Wechsel-Silvretta-Gleinalpe continental arc from the northern Gondwana.This process led to the formation of the Speik back-arc oceanic basin,a southwestern branch of the West Proto-Tethys Ocean.In the latest Cambrian–Early Ordovician,subduction initiation occurred in the Speik Ocean,which subsequently developed into an intra-oceanic arc system.During the Early Devonian,the Speik Ocean closed and the Wechsel-Silvretta-Gleinalpe continental arc reattached to the Gondwana,as evidenced by the metamorphic event at ca.400 Ma.展开更多
The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt(WKOB),and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks...The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt(WKOB),and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks in the WKOB.Sedimentary rocks in the WKOB received little attention in the past;however,they could provide important constraints on the evolution of the oceanic lithosphere.Here,a series of shales and greywackes found in the Kudi area of WKOB were studied to constrain their deposition ages and explore their significance in the evolution of the ProtoTethys oceanic crust.The U-Pb dating and europium anomaly(Eu/Eu^(*))were analyzed for detrital zircons from greywackes interlayers,while bulk rare earth elements and yttrium(REY)of the shales were measured.Detrital zircons U-Pb ages yield a maximum deposition age of 436 Ma for the greywackes and black shales,while the REY distribution patterns of the black shales are similar to those of the Tarim Ordovician Saergan shales.Accordingly,the studied WKOB black shales were deposited in the Proto-Tethys Ocean during the Late Ordovician-Early Silurian period.The maximum deposition age at 436 Ma may represent a minimum closure time of the Proto-Tethys Ocean,which is also supported by the absence of increases in Eu/Eu^(*)values during the Late Ordovician-Early Silurian.Besides,our Eu/Eu^(*)values in detrital zircons indicate diminished orogenesis during the Archean to Meso-Proterozoic,subduction-related accretion at the margins of the supercontinent Rodinia during the Neoproterozoic.展开更多
In order to understand the transmission mechanism of West Nile virus(WNv)in birds(especially crows)and mosquitoes populations,this paper extends the traditional ordinary differential model of WNv to a reaction-diffusi...In order to understand the transmission mechanism of West Nile virus(WNv)in birds(especially crows)and mosquitoes populations,this paper extends the traditional ordinary differential model of WNv to a reaction-diffusion system with more complex cross-diffusion.We explore the relationship between the basic reproduction number and cross-diffusion coefficients involving various parameters,and investigate the effect of vertical transmission of the virus on the transmission mechanism.We use the method of upper and lower solutions to investigate the existence of the coexistence solutions.The theoretical analysis and numerical simulation show that the WNv carried by birds and mosquitoes will coexist when the low-risk threshold R0*≥1,which is a disadvantage to the prevention and control of this virus,and disappear when the high-risk threshold R*0≤1,which is an advantage to that.展开更多
This paper examines the classic Chinese novel Journey to the West through the lens of rational choice theory,with a particular focus on the logic of cultivation and behavioral decision-making.By incorporating the noti...This paper examines the classic Chinese novel Journey to the West through the lens of rational choice theory,with a particular focus on the logic of cultivation and behavioral decision-making.By incorporating the notion of“inner cultivation”(xin xing xiulian)into the analytical framework,we introduce the concept of the“cultivating economic agent,”aiming to explore how rationality is generated,evolved,and transcended throughout the spiritual journey.The study argues that,in the context of Eastern culture,rationality is not merely an innate or static faculty but one that can be cultivated and transformed.Through textual analysis of the behavioral trajectories of Sun Wukong,Zhu Bajie,and Tang Sanzang,we uncover a structured behavioral logic of“goal orientation–institutional discipline–purification of the mind.”The findings suggest that although cultivation behaviors are not utilitarian decisions per se,they exhibit rational characteristics such as goal stability,autonomous will,and embedded incentives.展开更多
Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic...Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.展开更多
Coupled dissolution-precipitation is one of the critical processes influencing the mineralogical and geochemical evolution of pegmatites.This mechanism involves the simultaneous dissolution of primary mineral phases a...Coupled dissolution-precipitation is one of the critical processes influencing the mineralogical and geochemical evolution of pegmatites.This mechanism involves the simultaneous dissolution of primary mineral phases and the precipitation of secondary phases,driven by changes in the chemical environment,often mediated by hydrothermal fluids.The Bailongshan Li deposit,located in the West Kunlun region of northwest China,is a significant geological formation known for its rich lithium content and associated rare metals such as tantalum,niobium,and tin.This study investigates the coupled dissolution-precipitation processes that have played a crucial role in the mineralization of this deposit,focusing on key minerals,including cassiterite(Cst),columbite-group minerals(CGM),and elbaite(Elb).Using a combination of petrographic analysis,back-scattered electron(BSE)imaging,cathodoluminescence(CL)imaging,and micro X-ray fluorescence(XRF)mapping,we examined the textural and chemical characteristics of these minerals.Our findings reveal intricate patchy zoning patterns and element distributions(indicated by the Nb,Ta,W,Mn,Fe,Hf,Ti for CGM;Hf,Ti Rb,W,Nb,Ta for Cst;Ti,Zn,Fe,W,Hf,Mn,K for Elb)that indicate multiple stages of mineral alteration driven by fluid-mediated processes.The coupled dissolution-precipitation mechanisms observed in the Bailongshan deposit have resulted in significant redistribution and enrichment of economically valuable elements.The study highlights the importance of hydrothermal fluids in altering primary mineral phases and precipitating secondary phases with distinct compositions.These processes not only modified the mineralogical makeup of the pegmatite but also enhanced its economic potential by concentrating rare metals.Signatures of coupled dissolutionprecipitation processes can serve as an essential tool for mineral exploration,guiding the search for high-grade zones within similar pegmatitic formations.展开更多
BACKGROUND The global prevalence of diabetes among adults aged 29-79 years was found to be 10.5%.It is a global public health threat with a rising trend in morbidity and mortality.Poor glycemic control(GC)among patien...BACKGROUND The global prevalence of diabetes among adults aged 29-79 years was found to be 10.5%.It is a global public health threat with a rising trend in morbidity and mortality.Poor glycemic control(GC)among patients with type 2 diabetes mellitus(T2DM)is a major determinant of diabetes-related complications.There are limited data on GC and associated factors among patients with T2DM in South West Region,Cameroon.AIM To assess GC and identify contributing factors among patients with T2DM in a regional hospital in South West Region,Cameroon.METHODS A cross-sectional study was conducted from February 2022 to July 2022 among 131 participants in Limbe Regional Hospital who were selected by convenience.Glycated hemoglobin(HbA1c)was measured by ion-exchange chromatography.Sociodemographic,clinical,and lifestyle data were collected,entered into Excel,and exported to Statistical Package for Social Sciences version 22 for analysis.A multivariate logistic regression analysis was conducted to assess the association between explanatory variables and GC.The level of significance was set at P<0.05.RESULTS The mean age was 56±5.1 years.Eighty-eight(67.2%)patients were female.The mean HbA1c was 8.8%±1.8%.Poor GC(HbA1c≥7%)was registered in 106(80.9%;95%confidence interval:73.1%-87.3%)participants.Lack of self-monitoring of blood glucose at home was associated with poor GC(adjusted odds ratio:3.858,95%confidence interval:1.262-11.800;P=0.018).CONCLUSION The majority of patients with T2DM had poor GC.Absence of self-monitoring of blood glucose at home was the main contributing factor for poor GC.展开更多
Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate w...Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.展开更多
0 INTRODUCTION Orogenic belts are commonly built by multiple-stage processes involving oceanic subduction and continental collisions that result in the generation of magma with distinct geochemical compositions,as exe...0 INTRODUCTION Orogenic belts are commonly built by multiple-stage processes involving oceanic subduction and continental collisions that result in the generation of magma with distinct geochemical compositions,as exemplified by Central Asian Orogenic Belts(e.g.,Wang et al.,2024;Yin et al.,2024;Xiao et al.,2005)and the Tethyan tectonic domains(e.g.,Chen et al.,2024;Li et al.,2024;Tao et al.,2024a;Gehrels et al.,2011;Yin and Harrison,2000).展开更多
Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon...Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42375024).
文摘As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study,it is revealed that the intensity of the SPCZ can change the characteristics of sea ice in the West Antarctica during austral autumn,which is significantly independent of the El Niño-Southern Oscillation(ENSO).Observational and numerical results suggest that a stronger-than-usual SPCZ can generate a poleward-propagating Rossby wave train along a great circular route and induce a weakening of the Amundsen Sea Low(ASL)near West Antarctica,which may somewhat offset the teleconnections exerted by ENSO.These changes in the strength and zonal extent of ASL is noticeable and robustly lead to a tripole response of sea-ice perturbations in the Ross,Amundsen,and Weddell Seas.We find that the wind-driven dynamical processes determine the local sea-ice changes,while the influence from thermodynamic processes is trivial.This research underscores the need to consider the SPCZ variability for a comprehensive understanding of sea-ice changes in West Antarctica on interannual timescales.
文摘As a geopolitical bloc,the West is suffering unprecedented shocks.Once shared values are beginning to collapse,the shared security concept is rapidly diverging,and the shared view of order is also tending to disintegrate.There are more and more claims in the world,especially within the West,that the West has come to an end.Whether the West has ended or is heading toward its end is still a matter of opinion.However,it is undeniable that major problems have emerged within the West and some fundamental changes have taken place.Moreover,due to their structural reasons,these changes are not temporary and are likely to be a long-term trend.The West has long played an important role in many areas such as international politics,economy,and security.Its major changes will inevitably have a profound impact on the world order.The West will be further divided,and the opposition and confrontation between the West and non-West may tend to fade.The multipolarization of the world and the democratization of international relations will accelerate.
文摘Key West is in the state of Florida.It is the southernmost city in the USA.That means it is the city farthest to the south.It is very close to Cuba,another country.
基金National Natural Science Foundation of China,No.42201170Young Elite Scientists Sponsorship Program by CAST,No.2022QNRC001。
文摘Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.
基金Sponsored by Key Project of Hangzhou Science and Technology Bureau(20191203B78).
文摘The West Lake area and water system in West Lake scenic area of Hangzhou City directly affect the soil properties of waterfront lawn beds,which in turn have a significant impact on the growth of waterfront lawns.In order to further improve the quality of lawns,the conditions of 10 waterfront lawn beds in West Lake scenic area were tested and analyzed.The results showed that the waterfront lawn beds in West Lake scenic area were prone to salinization,with moderate or high pH values,moderate overall organic matter content,relatively sufficient nitrogen and phosphorus elements,and relatively deficient potassium elements.The contents of exchangeable calcium in all samples were higher than the lower limit,and the contents of exchangeable sodium,exchangeable magnesium,and available manganese in the soil were moderate or low,while the contents of available copper were moderate or high.
基金supported by the National Natural Science Foundation of China(Nos.42250202,92162323,42272075)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24lgqb01).
文摘Understanding the formation of lithium-rich pegmatites is critical for meeting global lithium demand.The 509 Daobanxi Li pegmatite deposit,located in the West Kunlun orogenic belt of northwestern China,represents a significant example of an LCT-type(Li-Cs-Ta)pegmatite system.This study investigates the paragenetic sequence of lithium(Li)minerals and the factors controlling their crystallization,providing new insights into the magmatic-hydrothermal evolution of rare-element pegmatites.Pegmatite dikes exhibit distinct zonation,comprising a wall rock zone,a border zone(aplitic layer),and a core zone(pegmatitic layer),with Li mineralization concentrated in the pegmatitic and aplitic layers.The primary Li minerals include spodumene(Spd),montebrasite(Mbs),eucryptite(Ecr),elbaite(Elb),and lepidolite(Lpd),which crystallize in the order of spodumene→montebrasite→elbaite→lepidolite.Spodumene,the dominant Li-bearing mineral,crystallizes from a Li-saturated melt during the magmatic stage.Montebrasite,a Li-phosphate mineral,forms in P-rich environments,coexisting with spodumene and columbite-group minerals(CGM).During the magmatic-hydrothermal transition,elbaite crystallizes from a B-rich melt,exhibiting skeletal and patchy zoning due to undercooling and disequilibrium crystallization.Hydrothermal alteration leads to the breakdown of spodumene and the formation of secondary minerals such as eucryptite and lepidolite,with lepidolite being the final Li-bearing phase,enriched in fluorine.The coupled dissolution-precipitation processes during the magmatic-hydrothermal transition play a critical role in the remobilization and enrichment of rare elements such as Li,Nb,Ta,and Sn.This deposit,characterized by spodumene crystallization in the Spd+Quartz stability field(≥300 MPa,≤725℃)and subsequent alteration to Ecr+quartz assemblages(<270℃,<160 MPa),exhibits broader temperature-pressure conditions exceeding typical global pegmatites like Tanco,with no petalite formation observed due to its persistent exclusion from petalite stability fields throughout mineralization.The shear zone controls the pegmatite emplacement and lithium enrichment in the 509 Daobanxi lithium deposit,and its deformation-fluid coupling mechanism provides new insights for the exploration of LCT pegmatite deposits.The present study highlights the importance of understanding both magmatic and hydrothermal processes in the formation of LCT-type pegmatites and provides valuable insights for the exploration of critical metal resources in similar geological settings.
基金supported by the Geological Investigation Project(DD20250209005,DD20242873,and DD20221643)the National Natural Science Foundation of China(Nos.42074112,4171101169 and 42174117)Japan Society for the Promotion of Science(No.19H01996).
文摘The subduction and closure history of the Paleo-Tethyan Ocean is of significant importance to the formation of the Alpine-Himalayan orogenic belt.However,in West Qinling,China,the evolution of the subducted Paleo-Tethyan oceanic slab in the mantle remains unclear.In this work,we determine high-resolution P-wave azimuthal anisotropic tomography of the crust and upper mantle beneath west Qinling by inverting newly collected local and teleseismic data.The local earthquakes are relocated by jointly using permanent and portable stations and weighted by their hypocentral errors during the inversion.Our model reveals a slab-like high P-wave velocity(V_(p))anomaly below 300 km depth and significant depth variations of anisotropy in the upper mantle beneath the West Qinling orogen.By comparing with previous geophysical results and integrating with geological and geochemical findings,we interpret that this high-V_(p)anomaly is most likely the subducted Mianlue oceanic slab preserved in the upper mantle and the mantle transition zone since the early Mesozoic.Beneath the Songpan-Ganzi block and the Longzhong basin,low-V anomalies with weak azimuthal anisotropy suggest a vertical mantle upwelling at a depth of 120 to 200 km,providing positive buoyancy to the subducted oceanic slab and extends its stagnation duration in the upper mantle.
基金BIO4Africa Project which is funded by the European Union(Horizon 2020-No.101000762).
文摘The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents a sustainable strategy to mitigate lignocellulosic waste,reduce reliance on fossil resources,and lower environmental pollution.This approach also creates economic opportunities for rural African communities by generating diverse income sources for workers in collection,processing,and manufacturing.As a result,the integration of agricultural residues into biocomposites production not only addresses environmental concerns but also fosters economic growth and supports rural development.In this review,five biomasses from West Africa are examined,focusing on their production,chemical composition,physical and mechanical properties,and potential applications in biocomposites.The five biomasses listed are cocoa pod husks,oil palm empty fruit bunches,rice husks,millet stalks,and typha stalks.Key parameters,such as the type of binder,fiber dimensions,fiber-to-binder ratio,and the strength of fiber-binder adhesion,are systematically studied to assess their influence on the overall performance of the resulting composites.Special attention is given to understanding how these factors affect mechanical properties(e.g.,strength and flexibility),thermal behavior(e.g.,insulation capacity and heat resistance),and physico-chemical characteristics(e.g.,moisture absorption,density,and chemical stability).This comprehensive analysis provides insights into optimizing composite formulations for enhanced functionality and sustainability.This study is essential to optimize the use of agricultural residues inWest Africa for biocomposites,tackling waste issues,promoting sustainability,and filling research gaps on their properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272244 and 91755212)Taishan Scholars(Grant No.ts20190918).
文摘Subduction initiation is a critical part of the plate tectonic system,but its geodynamic process is still poorly understood due to the lack of well-preserved geological records.Based on new zircon U–Pb–Hf isotopic and whole-rock geochemical data,we report the first discovery of a latest Cambrian–Early Ordovician forearc-arc rock sequence in the Eastern Alps.This sequence includes granitic gneisses,amphibolites,and amphibole plagiogneisses from the ophiolitic Speik Complex and Gleinalpe Complex.These rocks exhibit geochemical affinities with typical oceanic plagiogranites,forearc basalts(FABs),and island arc basalts,respectively.The latest Cambrian plagiogranitic protoliths(491±2 Ma)are shearing-type plagiogranites that were formed in the tectonic setting of forearc spreading.The latest Cambrian FABs(496–489 Ma)have similar geochemical compositions and positiveεHf(t)values(+2.5 to+14.9)to the depleted mid-ocean ridge basalts.However,they show depletion in high field strength elements(HFSEs;e.g.,Nb,Ta,and Zr)and have relatively low Ti/V ratios.These features suggest that they were derived from a depleted mantle source modified by subducting slab-released components in a forearc environment.The Early Ordovician basaltic protoliths(476–472 Ma)of amphibole plagiogneisses show enrichment in large ion lithophile elements and depletion in HFSEs(e.g.Nb,Ta,Zr,and Hf),implying a mature island arc environment.These metaigneous rocks,along with the coeval boninite-like high-Mg amphibolites near the study area,form a typical rock sequence resembling that of the Izu–Bonin–Mariana(IBM)arc system.The Speik and Gleinalpe complexes document a complete magmatic evolution from subduction initiation to mature arc development within the West Proto-Tethys Ocean.Integrating our new data with published work,we reconstruct the late Ediacaran–early Paleozoic tectonic evolution of the northern Gondwana.During the late Ediacaran–early Cambrian,the rollback of the West Proto-Tethys oceanic plate triggered the separation of the Wechsel-Silvretta-Gleinalpe continental arc from the northern Gondwana.This process led to the formation of the Speik back-arc oceanic basin,a southwestern branch of the West Proto-Tethys Ocean.In the latest Cambrian–Early Ordovician,subduction initiation occurred in the Speik Ocean,which subsequently developed into an intra-oceanic arc system.During the Early Devonian,the Speik Ocean closed and the Wechsel-Silvretta-Gleinalpe continental arc reattached to the Gondwana,as evidenced by the metamorphic event at ca.400 Ma.
基金financially supported by the National Major Science and Technology Project of China(No.2016ZX05004-004)the State Scholarship Grant from the China Scholarship Council(CSC)to Yinggang Zhang。
文摘The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt(WKOB),and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks in the WKOB.Sedimentary rocks in the WKOB received little attention in the past;however,they could provide important constraints on the evolution of the oceanic lithosphere.Here,a series of shales and greywackes found in the Kudi area of WKOB were studied to constrain their deposition ages and explore their significance in the evolution of the ProtoTethys oceanic crust.The U-Pb dating and europium anomaly(Eu/Eu^(*))were analyzed for detrital zircons from greywackes interlayers,while bulk rare earth elements and yttrium(REY)of the shales were measured.Detrital zircons U-Pb ages yield a maximum deposition age of 436 Ma for the greywackes and black shales,while the REY distribution patterns of the black shales are similar to those of the Tarim Ordovician Saergan shales.Accordingly,the studied WKOB black shales were deposited in the Proto-Tethys Ocean during the Late Ordovician-Early Silurian period.The maximum deposition age at 436 Ma may represent a minimum closure time of the Proto-Tethys Ocean,which is also supported by the absence of increases in Eu/Eu^(*)values during the Late Ordovician-Early Silurian.Besides,our Eu/Eu^(*)values in detrital zircons indicate diminished orogenesis during the Archean to Meso-Proterozoic,subduction-related accretion at the margins of the supercontinent Rodinia during the Neoproterozoic.
基金Supported by the Anhui Province Graduate Education Quality Engineering Project(2022jyjxggyj168)Anhui Province Higher Education Provincial-Level Quality Engineering Major Project(2022jcbs020)Anhui Province Higher Education Provincial-Level Quality Engineering General Project(2022jyxm527).
文摘In order to understand the transmission mechanism of West Nile virus(WNv)in birds(especially crows)and mosquitoes populations,this paper extends the traditional ordinary differential model of WNv to a reaction-diffusion system with more complex cross-diffusion.We explore the relationship between the basic reproduction number and cross-diffusion coefficients involving various parameters,and investigate the effect of vertical transmission of the virus on the transmission mechanism.We use the method of upper and lower solutions to investigate the existence of the coexistence solutions.The theoretical analysis and numerical simulation show that the WNv carried by birds and mosquitoes will coexist when the low-risk threshold R0*≥1,which is a disadvantage to the prevention and control of this virus,and disappear when the high-risk threshold R*0≤1,which is an advantage to that.
文摘This paper examines the classic Chinese novel Journey to the West through the lens of rational choice theory,with a particular focus on the logic of cultivation and behavioral decision-making.By incorporating the notion of“inner cultivation”(xin xing xiulian)into the analytical framework,we introduce the concept of the“cultivating economic agent,”aiming to explore how rationality is generated,evolved,and transcended throughout the spiritual journey.The study argues that,in the context of Eastern culture,rationality is not merely an innate or static faculty but one that can be cultivated and transformed.Through textual analysis of the behavioral trajectories of Sun Wukong,Zhu Bajie,and Tang Sanzang,we uncover a structured behavioral logic of“goal orientation–institutional discipline–purification of the mind.”The findings suggest that although cultivation behaviors are not utilitarian decisions per se,they exhibit rational characteristics such as goal stability,autonomous will,and embedded incentives.
文摘Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.
基金jointly supported by the National Natural Science Foundation of China(Nos.42250202,92162323,42272075)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24lgqb001)+1 种基金the Natural Science Foundation Project of Guangdong Province(No.2022A1515010003)the Guangdong Province Introduced Innovative R&D Team of Big Data—Mathematical Earth Sciences and Extreme Geological Events Team(No.2021ZT09H399)。
文摘Coupled dissolution-precipitation is one of the critical processes influencing the mineralogical and geochemical evolution of pegmatites.This mechanism involves the simultaneous dissolution of primary mineral phases and the precipitation of secondary phases,driven by changes in the chemical environment,often mediated by hydrothermal fluids.The Bailongshan Li deposit,located in the West Kunlun region of northwest China,is a significant geological formation known for its rich lithium content and associated rare metals such as tantalum,niobium,and tin.This study investigates the coupled dissolution-precipitation processes that have played a crucial role in the mineralization of this deposit,focusing on key minerals,including cassiterite(Cst),columbite-group minerals(CGM),and elbaite(Elb).Using a combination of petrographic analysis,back-scattered electron(BSE)imaging,cathodoluminescence(CL)imaging,and micro X-ray fluorescence(XRF)mapping,we examined the textural and chemical characteristics of these minerals.Our findings reveal intricate patchy zoning patterns and element distributions(indicated by the Nb,Ta,W,Mn,Fe,Hf,Ti for CGM;Hf,Ti Rb,W,Nb,Ta for Cst;Ti,Zn,Fe,W,Hf,Mn,K for Elb)that indicate multiple stages of mineral alteration driven by fluid-mediated processes.The coupled dissolution-precipitation mechanisms observed in the Bailongshan deposit have resulted in significant redistribution and enrichment of economically valuable elements.The study highlights the importance of hydrothermal fluids in altering primary mineral phases and precipitating secondary phases with distinct compositions.These processes not only modified the mineralogical makeup of the pegmatite but also enhanced its economic potential by concentrating rare metals.Signatures of coupled dissolutionprecipitation processes can serve as an essential tool for mineral exploration,guiding the search for high-grade zones within similar pegmatitic formations.
文摘BACKGROUND The global prevalence of diabetes among adults aged 29-79 years was found to be 10.5%.It is a global public health threat with a rising trend in morbidity and mortality.Poor glycemic control(GC)among patients with type 2 diabetes mellitus(T2DM)is a major determinant of diabetes-related complications.There are limited data on GC and associated factors among patients with T2DM in South West Region,Cameroon.AIM To assess GC and identify contributing factors among patients with T2DM in a regional hospital in South West Region,Cameroon.METHODS A cross-sectional study was conducted from February 2022 to July 2022 among 131 participants in Limbe Regional Hospital who were selected by convenience.Glycated hemoglobin(HbA1c)was measured by ion-exchange chromatography.Sociodemographic,clinical,and lifestyle data were collected,entered into Excel,and exported to Statistical Package for Social Sciences version 22 for analysis.A multivariate logistic regression analysis was conducted to assess the association between explanatory variables and GC.The level of significance was set at P<0.05.RESULTS The mean age was 56±5.1 years.Eighty-eight(67.2%)patients were female.The mean HbA1c was 8.8%±1.8%.Poor GC(HbA1c≥7%)was registered in 106(80.9%;95%confidence interval:73.1%-87.3%)participants.Lack of self-monitoring of blood glucose at home was associated with poor GC(adjusted odds ratio:3.858,95%confidence interval:1.262-11.800;P=0.018).CONCLUSION The majority of patients with T2DM had poor GC.Absence of self-monitoring of blood glucose at home was the main contributing factor for poor GC.
基金Under the auspices of the National Key Research and Development Program of China(No.2022YFD1500501)the Innovation Team Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)+2 种基金the National Natural Science Foundation of China(No.41971066)the Key Laboratory Foundation of Mollisols Agroecology(No.2020ZKHT-03)the High Tech Fund Project of S&T Cooperation between Jilin Province and Chinese Academy of Sciences(No.2022SYHZ0018)。
文摘Water scarcity and soil salinization pose significant challenges to agriculture in the West Liaohe Plain,eastern Inner Mongolia,China.Shallow-buried drip irrigation can improve soil water use efficiency to alleviate water shortage in agriculture and the application of lignite humic acid reduces the adverse effects of soil salinization.However,further research is needed to investigate the effects of different application rates of lignite humic acid and humic acid-based combined amendment on soil physicochemical properties,nutrient contents,and crop yield in saline-sodic farmlands under shallow-buried drip irrigation.A two-year field experiment was conducted with control without any amendment(CK),three treatments amended with 3 t/ha(H1),6 t/ha(H2),and 12 t/ha(H3)lignite humic acid,and three application rates with 15 t/ha(T1),22.5 t/ha(T2),and 30 t/ha(T3)lignite humic acid-based combined amendment in 2021 and2022.The results showed that H3 reduced soil bulk density,p H,electrical conductivity,and total alkalinity,while increasing the contents of soil organic matter,total nitrogen,and available potassium in the two-year experiment.Moreover,the maize yield in H3 increased by an average of 35.5%.T2 decreased soil bulk density,p H,total alkalinity,and increased maize yield by 16.2%,compared to the first year.These results suggest that T2 consistently improved both soil quality and crop yield.Correlation analyses showed that lignite humic acid and its complexes promote maize growth and increase yield by increasing soil organic matter and total nitrogen while reducing soil salinity and total alkalinity.Based on the comprehensive analysis of the field data and the results of the comprehensive evaluation of soil quality,it was determined that the appropriate improvement measures for saline-sodic farmlands under shallow-buried drip irrigation are the application of 12 t/ha of lignite humic acid and 22.5 t/ha of lignite humic acid-based combined amendment.This study demonstrates the effectiveness of lignite humic acid and its combined amendment in mitigating the constraints of saline-sodic farmlands and enhancing crop yields,providing a sustainable solution for improving saline-sodic farmlands in the West Liaohe Plain.
基金supported by the National Key Research and Development Project(No.2022YFC2903302)the Second Tibet Plateau Scientific Expedition and Research Program(STEP),(No.2019QZKK0802)+2 种基金the National Natural Science Foundation of China(No.42361144841)the Chinese Academy of Geological Sciences Basal Research Fund(No.JKYZD202402)the Scientific Research Fund Project of BGRIMM Technology Group(No.JTKY202427822)。
文摘0 INTRODUCTION Orogenic belts are commonly built by multiple-stage processes involving oceanic subduction and continental collisions that result in the generation of magma with distinct geochemical compositions,as exemplified by Central Asian Orogenic Belts(e.g.,Wang et al.,2024;Yin et al.,2024;Xiao et al.,2005)and the Tethyan tectonic domains(e.g.,Chen et al.,2024;Li et al.,2024;Tao et al.,2024a;Gehrels et al.,2011;Yin and Harrison,2000).
文摘Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.
