The application effect of 30 introduced flowering shrubs in landscape in Hefei City was comprehensively evaluated by the analytic hierarchy process(APH).A comprehensive evaluation model was established by using factor...The application effect of 30 introduced flowering shrubs in landscape in Hefei City was comprehensively evaluated by the analytic hierarchy process(APH).A comprehensive evaluation model was established by using factors such as plant type,resistance and drought tolerance of introduced flowering shrubs.The results show that the application effect of grade-I introduced flowering shrubs(including 12 kinds,e.g.Lantanacamara)was the best(j≥2.6),and that of grade-II introduced flowering shrubs(including 14 kinds,e.g.Abelia×grandiflora‘Francis Mason’)was better(2.2≤j<2.6),while that of grade-III introduced flowering shrubs(including 4 kinds,e.g.Ligustrum×vicaryi)was moderate(j<2.2).The evaluation results can provide reference for the application effect of introduced flowering shrubs in landscape in Hefei City.展开更多
Invasive species may pose significant threats to biodiversity and ecosystem structure and functioning.The number of introduced species that have become invasive is substantial and is rapidly increasing.Identifying pot...Invasive species may pose significant threats to biodiversity and ecosystem structure and functioning.The number of introduced species that have become invasive is substantial and is rapidly increasing.Identifying potentially invasive species and preventing their expansion are of critical importance in invasion ecology.Phylogenetic relatedness between invasive and native species has been used in predicting invasion success.Previous studies on the phylogenetic relatedness of plants at the transition from naturalization to invasion have shown mixed results,which may be because different methods were used in different studies.Here,I use the same method to analyze two comprehensive data sets from South Africa and China,using two phylogenetic metrics reflecting deep and shallow evolutionary histories,to address the question whether the probability of becoming invasive is higher for naturalized species distantly related to the native flora.My study suggests that the probability of becoming invasive is higher for naturalized species closely related to the native flora.The finding of my study is consistent with Darwin's preadaptation hypothesis.展开更多
Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measur...Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measure, a principal method is designed for quantifying the detectabilities of fault detection algorithms over special datasets.展开更多
Avian malaria and related haemosporidian parasites can negatively impact fitness in many songbirds.Research on the malaria infection and its physiological costs on their avian hosts is heavily skewed toward native pas...Avian malaria and related haemosporidian parasites can negatively impact fitness in many songbirds.Research on the malaria infection and its physiological costs on their avian hosts is heavily skewed toward native passerines,with exotic species underrepresented.However,introduced species may carry on and spread new pathogens to native species,and play a role on parasite transmission cycle in invaded bird communities as pathogen reservoir.Here,we molecularly assess the prevalence and diversity of haemosporidian parasites in three introduced wetland passerines(the Red Avadavat Amandava amandava,the Yellow-crowned Bishop Euplectes afer,and the Common Waxbill Estrilda astrild)captured during the same season in southwestern Spain.We also explored the relation between parasite infection,body condition,haematocrit,and uropygial gland volume.We detected an overall parasite prevalence of 3.55%,where Common Waxbills showed higher prevalence(6.94%)than Red Avadavats(1.51%).None Yellow-crowned Bishops were infected with haemosporidians.Almost 60%of infections were caused by Leucocytozoon,and about 40%by Plasmodium.We identified four unique lineages of Plasmodium and three of Leucocytozoon.Moreover,91%of the identified host-parasite interactions represented new host records for these haemosporidian parasites.Parasite infection was not related to body condition,haematocrit,and uropygial gland volume of the wetland passerines.Haematocrit values varied seasonally among bird species.Additionally,haematocrit was positively related to body condition in the Yellow-crowned Bishops,but not in the other species.Red Avadavats had higher haematocrit levels than Yellow-crowned Bishops,whereas Common Waxbills showed the lower haematocrit values.The uropygial gland volume was positively correlated with body condition in all bird species.Common Waxbills showed higher uropygial gland volumes related to their body size than birds from other two species.These outcomes highlight the importance of exotic invasive species in the transmission dynamics of haemosporidian parasites.展开更多
Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q...Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.展开更多
This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in...This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.展开更多
Extreme droughts are anticipated to have detrimental impacts on forest ecosystems,especially in water-limited regions,due to the influence of climate change.However,considerable uncertainty remains regarding the patte...Extreme droughts are anticipated to have detrimental impacts on forest ecosystems,especially in water-limited regions,due to the influence of climate change.However,considerable uncertainty remains regarding the patterns in species-specific responses to extreme droughts.Here,we conducted a study integrating dendrochronology and remote sensing methods to investigate the mosaic-distributed maple-oak(native)natural forests and poplar plantations(introduced)in the Horqin Sandy Land,Northeast China.We assessed the impacts of extreme droughts on tree performances by measuring interannual variations in radial growth and vegetation index.The results showed that precipitation and self-calibrated palmer drought severity index(scPDSI)are the major factors influencing tree-ring width index(RWI)and normalized difference vegetation index(NDVI).The severe droughts between 2000 and 2004 resulted in reduced RWI in the three studied tree species as well as led to NDVI reductions in both the maple-oak natural forests and the poplar plantations.The RWI reached the nadir during the2000-2004 severe droughts and remained at low levels two years after the severe drought,creating a legacy effect.In contrast to the lack of significant correlation between RWI and scPDSI,NDVI exhibited a significant positive correlation with scPDSI indicating the greater sensitivity of canopy performance to droughts than radial growth.Furthermore,interspecific differences in RWI and NDVI responses were observed,with the fast-growing poplar species experiencing a more significant RWI decrease and more negative NDVI anomaly during severe droughts than native species,highlighting the species-specific trade-offs between drought resilience and growth rate.This study emphasizes the importance of combining tree-level radial growth with landscape-scale canopy remote sensing to understand forest resilience and response.Our study improves our understanding of forest responses to extreme drought and highlights species differences in climate responses,offering crucial insights for optimizing species selection in sustainable afforestation and forest management in water-limited regions under the influence of climate change.展开更多
I recently got the opportunity to visit China to attend a seminar organized by the China Counsel for the Promotion of International Trade(CCPIT),for participants from the Belt and Road Initiative(BRI)countries.The pur...I recently got the opportunity to visit China to attend a seminar organized by the China Counsel for the Promotion of International Trade(CCPIT),for participants from the Belt and Road Initiative(BRI)countries.The purpose of the seminar was to invite the delegates from BRI countries,and give them firsthand experience of the Chinese development miracle by introducing them to Chinese history,its governance methodology and how it has managed to carry out its significant progress in the last three decades,for example,by following policies that facilitated entrepreneurship,and providing businesses the right kind of platform.展开更多
As an enthusiast of travelling,a young French entrepreneur has dedicated her life to sharing the vitality of China’s eastern economic hub with more people.ON the streets of Shanghai,China’s eastern mega city,you can...As an enthusiast of travelling,a young French entrepreneur has dedicated her life to sharing the vitality of China’s eastern economic hub with more people.ON the streets of Shanghai,China’s eastern mega city,you can often see a young French woman leading a group of tourists around the city on citywalks,introducing the history and culture of the metropolis to them in Chinese,English,and French.展开更多
During the annual meeting of the National People’s Congress(NPC),China’s top legislature,in March,President Xi Jinping stressed focusing on high-quality development as the top priority and developing new quality pro...During the annual meeting of the National People’s Congress(NPC),China’s top legislature,in March,President Xi Jinping stressed focusing on high-quality development as the top priority and developing new quality productive forces according to local conditions while deliberating with lawmakers from Jiangsu Province.Following the path that President Xi emphasized,SAIC-GM-Wuling Automobile Co.,Ltd.has been committed to modernizing research and development(R&D),introducing intelligent manufacturing,upgrading the automobile industry.展开更多
BACKGROUND Paravalvular leak(PVL),also known as paravalvular prosthetic regurgitation,is not a rare complication after surgical valve replacement,and it may cause varying degrees of heart failure.The transcatheter clo...BACKGROUND Paravalvular leak(PVL),also known as paravalvular prosthetic regurgitation,is not a rare complication after surgical valve replacement,and it may cause varying degrees of heart failure.The transcatheter closure of PVL is technically demanding and challenging.CASE SUMMARY A 68-year-old man presented with degenerative mitral regurgitation with heart failure,New York Heart Association functional class 3.He received bioprosthetic mitral valve replacement in December 2019.PVL was noted at the location of the aorto-mitral curtain in transesophageal echocardiography without signs of endocarditis or dehiscence of the bioprosthetic valve.Transseptal transcatheter closure of the mitral PVL was performed efficiently using the EchoNavigator virtual marker and Agilis NxT steerable introducer.CONCLUSION This case highlights that the EchoNavigator virtual marker and Agilis NxT steerable introducer can facilitate transseptal transcatheter closure of mitral PVL by reducing the procedure time and contrast media.展开更多
Kissing gouramy (Helostoma temminckii) was introduced into Tasek Merimbun in the 1980's. We studied their genetic profile using allozyme electrophoresis and found that all loci were monomorphic. The loss of hetero...Kissing gouramy (Helostoma temminckii) was introduced into Tasek Merimbun in the 1980's. We studied their genetic profile using allozyme electrophoresis and found that all loci were monomorphic. The loss of heterozygotes may suggest that the gouramy are inbreds. They must have reproduced by repeated sib-mating over the years. The severe drought in Tasek Merimbun may have aggravated the genetic erosion further. The genetic variability of kissing gouramy in terms of % polymorphic loci, mean number of alleles per loci and observed heterozygosity level were lower than cyprinids in the same lake and kissing gouramy from the wild. We also note that kissing gouramy is a fast grower and may threaten the livelihood of indigenous fishes in the lake.展开更多
Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatel...Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.展开更多
With the physical method of micro-gap gas discharge, OH. radicals were produced by the ionization of O2 in air and H2O in the gaseous state, in order to explore more effective method totreat the ship's ballast water....With the physical method of micro-gap gas discharge, OH. radicals were produced by the ionization of O2 in air and H2O in the gaseous state, in order to explore more effective method totreat the ship's ballast water. The surface morphology of Al2O3 dielectric layer was analysed using Atomic Force Microscopy (AFM), where the size of Al2O3 particles was in the range of 2 μm to 5 μm. At the same time, the biochemical effect of hydroxyl radicals on the introduced organisms and the quality of ship's ballast water were studied. The results indicate that the main reasons of cell death are lipid peroxide and damage of the antioxidant enzyme system in Catalase (CAT), Peroxidase (POD) and Superoxide dismutase (SOD). In addition, the quality of the ballast water was greatly improved.展开更多
Aerodigestive cancer, like esophageal cancer or head and neck cancer, is well known to have a poor prognosis. It is often diagnosed in the late stages, with dysphagia being the major symptom. Insufficient nutrition an...Aerodigestive cancer, like esophageal cancer or head and neck cancer, is well known to have a poor prognosis. It is often diagnosed in the late stages, with dysphagia being the major symptom. Insufficient nutrition and lack of stimulation of the intestinal mucosa may worsen immune compromise due to toxic side effects. A poor nutritional status is a significant prognostic factor for increased mortality. Therefore, it is most important to optimize enteral nutrition in patients with aerodigestive cancer before and during treatment, as well as during palliative treatment. Percutaneous endoscopic gastrostomy(PEG) may be useful for nutritional support. However, PEG tube placement is limited by digestive tract stenosis and is an invasive endoscopic procedure with a risk of complications. There are three PEG techniques. The pull/push and introducer methods have been established as standard techniques for PEG tube placement. The modified introducer method, namely the direct method, allows for direct placement of a larger button-bumper-type catheter device. PEG tube placement using the introducer method or the direct method may be a much safer alternative than the pull/push method. PEG may be recommended in patients with aerodigestive cancer because of the improved complication rate.展开更多
With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of 02 and H2O. In this paper, the effect of biochemistry of hydroxyl...With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of 02 and H2O. In this paper, the effect of biochemistry of hydroxyl radicals on introduced organisms in ballast water was experimentally investigated. The results indicate that the contents of chlorophyl-a, chlorophyl-b, chlorophyl-c and carotenoid are decreased by 35%-4% within 8.0s and further to the lowest limit of test 5 minutes. In addition, the main reasons of cell death are the lipid peroxidation, the strong destruction to the monose, amylose, protein, DNA and RNA of cell, and damage in CAT, POD and SOD of antioxidant enzyme system.展开更多
Previous studies suggest that dipolarization fronts (DFs) are 1 to 3RE (RE is the earth radius) wide in the dawn-dusk direction. Recent kinetic simulations have found that DFs may break up into small-scale structures ...Previous studies suggest that dipolarization fronts (DFs) are 1 to 3RE (RE is the earth radius) wide in the dawn-dusk direction. Recent kinetic simulations have found that DFs may break up into small-scale structures after they are produced by reconnection. Motivated by this simulation, we revisited the scale size of DFs in the dawn-dusk direction by using Cluster observations during the years when the inter-distance among Cluster spacecraft was between 1000 and 2000 km. We selected the DFs that were detected by more than one spacecraft and estimated the radii of these DFs by a simple geometrical analysis, which is based on comparison of DF normals observed by different spacecraft. We found a few DFs that were only a few ion inertial lengths in the dawn-dusk direction. These results point out the importance of multi-scale coupling during the evolution of DFs.展开更多
The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free...The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN),from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diumal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Aky-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves o1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.展开更多
基金Sponsored by the Innovation and Entrepreneurship Training Planning Project for University Students in Anhui Province(S202212216129)Key Research Project of Natural Science in Universities of Anhui Province(2023AH051816)General Teaching Research Project of Anhui Province(2022jyxm665).
文摘The application effect of 30 introduced flowering shrubs in landscape in Hefei City was comprehensively evaluated by the analytic hierarchy process(APH).A comprehensive evaluation model was established by using factors such as plant type,resistance and drought tolerance of introduced flowering shrubs.The results show that the application effect of grade-I introduced flowering shrubs(including 12 kinds,e.g.Lantanacamara)was the best(j≥2.6),and that of grade-II introduced flowering shrubs(including 14 kinds,e.g.Abelia×grandiflora‘Francis Mason’)was better(2.2≤j<2.6),while that of grade-III introduced flowering shrubs(including 4 kinds,e.g.Ligustrum×vicaryi)was moderate(j<2.2).The evaluation results can provide reference for the application effect of introduced flowering shrubs in landscape in Hefei City.
文摘Invasive species may pose significant threats to biodiversity and ecosystem structure and functioning.The number of introduced species that have become invasive is substantial and is rapidly increasing.Identifying potentially invasive species and preventing their expansion are of critical importance in invasion ecology.Phylogenetic relatedness between invasive and native species has been used in predicting invasion success.Previous studies on the phylogenetic relatedness of plants at the transition from naturalization to invasion have shown mixed results,which may be because different methods were used in different studies.Here,I use the same method to analyze two comprehensive data sets from South Africa and China,using two phylogenetic metrics reflecting deep and shallow evolutionary histories,to address the question whether the probability of becoming invasive is higher for naturalized species distantly related to the native flora.My study suggests that the probability of becoming invasive is higher for naturalized species closely related to the native flora.The finding of my study is consistent with Darwin's preadaptation hypothesis.
基金supported by the National Key R&D Program of China (2021YFB1715000)the National Natural Science Foundation of China (U1811461, 62022013, 12150007, 62103450, 61832003, 62272137)。
文摘Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measure, a principal method is designed for quantifying the detectabilities of fault detection algorithms over special datasets.
基金support provided by Facility of Bioscience Applied Techniques of SAIUEx(financed by UEX,Junta de Extremadura,MICINN,FEDER and FSE)funded by Consejería de Economía e Infraestructura of the Junta de Extremadura and the European Regional Development Fund,a Way to Make Europe(research projects IB16121 and IB20089)+1 种基金supported by a postdoctoral grant from the Juan de la Cierva Subprogram(FJCI 2017-34109,MICINN)a postdoctoral contract for scientific excellence in the development of the Plan Propio de I+D+i of the UCLM(co-funded by the European Social Fund Plus(ESF+))。
文摘Avian malaria and related haemosporidian parasites can negatively impact fitness in many songbirds.Research on the malaria infection and its physiological costs on their avian hosts is heavily skewed toward native passerines,with exotic species underrepresented.However,introduced species may carry on and spread new pathogens to native species,and play a role on parasite transmission cycle in invaded bird communities as pathogen reservoir.Here,we molecularly assess the prevalence and diversity of haemosporidian parasites in three introduced wetland passerines(the Red Avadavat Amandava amandava,the Yellow-crowned Bishop Euplectes afer,and the Common Waxbill Estrilda astrild)captured during the same season in southwestern Spain.We also explored the relation between parasite infection,body condition,haematocrit,and uropygial gland volume.We detected an overall parasite prevalence of 3.55%,where Common Waxbills showed higher prevalence(6.94%)than Red Avadavats(1.51%).None Yellow-crowned Bishops were infected with haemosporidians.Almost 60%of infections were caused by Leucocytozoon,and about 40%by Plasmodium.We identified four unique lineages of Plasmodium and three of Leucocytozoon.Moreover,91%of the identified host-parasite interactions represented new host records for these haemosporidian parasites.Parasite infection was not related to body condition,haematocrit,and uropygial gland volume of the wetland passerines.Haematocrit values varied seasonally among bird species.Additionally,haematocrit was positively related to body condition in the Yellow-crowned Bishops,but not in the other species.Red Avadavats had higher haematocrit levels than Yellow-crowned Bishops,whereas Common Waxbills showed the lower haematocrit values.The uropygial gland volume was positively correlated with body condition in all bird species.Common Waxbills showed higher uropygial gland volumes related to their body size than birds from other two species.These outcomes highlight the importance of exotic invasive species in the transmission dynamics of haemosporidian parasites.
基金supported by the Ontario Centres of Excellence,Nipissing University Internal Research FundOntario/Baden-Württemberg Student Exchange Programthe Ontario/Baden-Württemberg Faculty Research Exchange
文摘Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.
文摘This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.
基金supported by the National Natural Science Foundation of China(Nos.32220103010,32192431,31722013)the National Key R&D Program of China(Nos.2023YFF1304201,2020YFA0608100)+1 种基金the Major Program of Institute of Applied EcologyChinese Academy of Sciences(No.IAEMP202201)。
文摘Extreme droughts are anticipated to have detrimental impacts on forest ecosystems,especially in water-limited regions,due to the influence of climate change.However,considerable uncertainty remains regarding the patterns in species-specific responses to extreme droughts.Here,we conducted a study integrating dendrochronology and remote sensing methods to investigate the mosaic-distributed maple-oak(native)natural forests and poplar plantations(introduced)in the Horqin Sandy Land,Northeast China.We assessed the impacts of extreme droughts on tree performances by measuring interannual variations in radial growth and vegetation index.The results showed that precipitation and self-calibrated palmer drought severity index(scPDSI)are the major factors influencing tree-ring width index(RWI)and normalized difference vegetation index(NDVI).The severe droughts between 2000 and 2004 resulted in reduced RWI in the three studied tree species as well as led to NDVI reductions in both the maple-oak natural forests and the poplar plantations.The RWI reached the nadir during the2000-2004 severe droughts and remained at low levels two years after the severe drought,creating a legacy effect.In contrast to the lack of significant correlation between RWI and scPDSI,NDVI exhibited a significant positive correlation with scPDSI indicating the greater sensitivity of canopy performance to droughts than radial growth.Furthermore,interspecific differences in RWI and NDVI responses were observed,with the fast-growing poplar species experiencing a more significant RWI decrease and more negative NDVI anomaly during severe droughts than native species,highlighting the species-specific trade-offs between drought resilience and growth rate.This study emphasizes the importance of combining tree-level radial growth with landscape-scale canopy remote sensing to understand forest resilience and response.Our study improves our understanding of forest responses to extreme drought and highlights species differences in climate responses,offering crucial insights for optimizing species selection in sustainable afforestation and forest management in water-limited regions under the influence of climate change.
文摘I recently got the opportunity to visit China to attend a seminar organized by the China Counsel for the Promotion of International Trade(CCPIT),for participants from the Belt and Road Initiative(BRI)countries.The purpose of the seminar was to invite the delegates from BRI countries,and give them firsthand experience of the Chinese development miracle by introducing them to Chinese history,its governance methodology and how it has managed to carry out its significant progress in the last three decades,for example,by following policies that facilitated entrepreneurship,and providing businesses the right kind of platform.
文摘As an enthusiast of travelling,a young French entrepreneur has dedicated her life to sharing the vitality of China’s eastern economic hub with more people.ON the streets of Shanghai,China’s eastern mega city,you can often see a young French woman leading a group of tourists around the city on citywalks,introducing the history and culture of the metropolis to them in Chinese,English,and French.
文摘During the annual meeting of the National People’s Congress(NPC),China’s top legislature,in March,President Xi Jinping stressed focusing on high-quality development as the top priority and developing new quality productive forces according to local conditions while deliberating with lawmakers from Jiangsu Province.Following the path that President Xi emphasized,SAIC-GM-Wuling Automobile Co.,Ltd.has been committed to modernizing research and development(R&D),introducing intelligent manufacturing,upgrading the automobile industry.
文摘BACKGROUND Paravalvular leak(PVL),also known as paravalvular prosthetic regurgitation,is not a rare complication after surgical valve replacement,and it may cause varying degrees of heart failure.The transcatheter closure of PVL is technically demanding and challenging.CASE SUMMARY A 68-year-old man presented with degenerative mitral regurgitation with heart failure,New York Heart Association functional class 3.He received bioprosthetic mitral valve replacement in December 2019.PVL was noted at the location of the aorto-mitral curtain in transesophageal echocardiography without signs of endocarditis or dehiscence of the bioprosthetic valve.Transseptal transcatheter closure of the mitral PVL was performed efficiently using the EchoNavigator virtual marker and Agilis NxT steerable introducer.CONCLUSION This case highlights that the EchoNavigator virtual marker and Agilis NxT steerable introducer can facilitate transseptal transcatheter closure of mitral PVL by reducing the procedure time and contrast media.
基金Universiti Brunei Darussalam for supporting the research project
文摘Kissing gouramy (Helostoma temminckii) was introduced into Tasek Merimbun in the 1980's. We studied their genetic profile using allozyme electrophoresis and found that all loci were monomorphic. The loss of heterozygotes may suggest that the gouramy are inbreds. They must have reproduced by repeated sib-mating over the years. The severe drought in Tasek Merimbun may have aggravated the genetic erosion further. The genetic variability of kissing gouramy in terms of % polymorphic loci, mean number of alleles per loci and observed heterozygosity level were lower than cyprinids in the same lake and kissing gouramy from the wild. We also note that kissing gouramy is a fast grower and may threaten the livelihood of indigenous fishes in the lake.
基金supported by the National High Technology Development Project of China under contract No. 2012AA10A404the Recommended International Advanced Agricultural Science and Technology Project of China under contract No. 2012-S5
文摘Seven microsatellite markers were used to evaluate the genetic diversity and differentiation of seven stocks of Litopenaeus vannamei, which were introduced from Central and South America to China. All seven microsatellite loci were polymorphic, with polymorphism information content(PIC) values ranging from 0.593 to 0.952. Totally 92 alleles were identified, and the number of alleles(Na) and effective alleles(Ne) varied between 4 and 21 and 2.7 and 14.6, respectively. Observed heterozygosity(Ho) values were lower than the expected heterozygosity(He) values(0.526–0.754), which indicated that the seven stocks possessed a rich genetic diversity. Thirty-seven tests were detected for reasonable significant deviation from Hardy-Weinberg equilibrium. Fis values were positive at five loci, suggesting that there was a relatively high degree of inbreeding within stocks. Pairwise Fst values ranged from 0.0225 to 0.151, and most of the stock pairs were moderately differentiated. Genetic distance and cluster analysis using UPGMA revealed a close genetic relationship of L. vannamei between Pop2 and Pop3. AMOVA indicated that the genetic variation among stocks(11.3%) was much lower than that within stocks(88.7%). Although the seven stocks had a certain degree of genetic differentiation and a rich genetic diversity, there is an increasing risk of decreased performance due to inbreeding in subsequent generations.
基金supported by the Key Project of National Support Plan from Science and Technology Ministry of China (2006BAC11B06) the Key Project of International Cooperation from the Ministry of Science and Technology of China (2005DFA20800)+1 种基金the Support Plan of National New Century Excellent Youth of China (NCET-04-0286, -05-0398) the Project of National Natural Science Foundation of China (No. 60371035)
文摘With the physical method of micro-gap gas discharge, OH. radicals were produced by the ionization of O2 in air and H2O in the gaseous state, in order to explore more effective method totreat the ship's ballast water. The surface morphology of Al2O3 dielectric layer was analysed using Atomic Force Microscopy (AFM), where the size of Al2O3 particles was in the range of 2 μm to 5 μm. At the same time, the biochemical effect of hydroxyl radicals on the introduced organisms and the quality of ship's ballast water were studied. The results indicate that the main reasons of cell death are lipid peroxide and damage of the antioxidant enzyme system in Catalase (CAT), Peroxidase (POD) and Superoxide dismutase (SOD). In addition, the quality of the ballast water was greatly improved.
文摘Aerodigestive cancer, like esophageal cancer or head and neck cancer, is well known to have a poor prognosis. It is often diagnosed in the late stages, with dysphagia being the major symptom. Insufficient nutrition and lack of stimulation of the intestinal mucosa may worsen immune compromise due to toxic side effects. A poor nutritional status is a significant prognostic factor for increased mortality. Therefore, it is most important to optimize enteral nutrition in patients with aerodigestive cancer before and during treatment, as well as during palliative treatment. Percutaneous endoscopic gastrostomy(PEG) may be useful for nutritional support. However, PEG tube placement is limited by digestive tract stenosis and is an invasive endoscopic procedure with a risk of complications. There are three PEG techniques. The pull/push and introducer methods have been established as standard techniques for PEG tube placement. The modified introducer method, namely the direct method, allows for direct placement of a larger button-bumper-type catheter device. PEG tube placement using the introducer method or the direct method may be a much safer alternative than the pull/push method. PEG may be recommended in patients with aerodigestive cancer because of the improved complication rate.
基金Key Project of National Foundation Research from Science and Tech-nology, Ministry of China (2002CCC00900), Key and General Projects of NSFC (No. 60371035) and Project of Society Development of Dalian (2004B3SF181).
文摘With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of 02 and H2O. In this paper, the effect of biochemistry of hydroxyl radicals on introduced organisms in ballast water was experimentally investigated. The results indicate that the contents of chlorophyl-a, chlorophyl-b, chlorophyl-c and carotenoid are decreased by 35%-4% within 8.0s and further to the lowest limit of test 5 minutes. In addition, the main reasons of cell death are the lipid peroxidation, the strong destruction to the monose, amylose, protein, DNA and RNA of cell, and damage in CAT, POD and SOD of antioxidant enzyme system.
基金supported by the National Natural Science Foundation of China (NSFC) under grant 41774154 and 41504123the Science Foundation of Jiangxi Province under grant 20122BAB21 2002+1 种基金the Nanchang University graduate innovation special fund project under grant CX2017106the Key Industry Innovation Chain of Shaanxi under grant 2018JQ4032
文摘Previous studies suggest that dipolarization fronts (DFs) are 1 to 3RE (RE is the earth radius) wide in the dawn-dusk direction. Recent kinetic simulations have found that DFs may break up into small-scale structures after they are produced by reconnection. Motivated by this simulation, we revisited the scale size of DFs in the dawn-dusk direction by using Cluster observations during the years when the inter-distance among Cluster spacecraft was between 1000 and 2000 km. We selected the DFs that were detected by more than one spacecraft and estimated the radii of these DFs by a simple geometrical analysis, which is based on comparison of DF normals observed by different spacecraft. We found a few DFs that were only a few ion inertial lengths in the dawn-dusk direction. These results point out the importance of multi-scale coupling during the evolution of DFs.
文摘The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN),from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diumal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Aky-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves o1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.