Object LAMOST J020623.21+494127.9(program star) in the thin disk of the Milky Way is reported as a highly r-process-enhanced r-II star with [Eu/Fe] = +1.32 and [Fe/H] =-0.54. The chemical profile of the star reflects ...Object LAMOST J020623.21+494127.9(program star) in the thin disk of the Milky Way is reported as a highly r-process-enhanced r-II star with [Eu/Fe] = +1.32 and [Fe/H] =-0.54. The chemical profile of the star reflects the intrinsic composition of the gas cloud present at its birth. Using an abundance decomposition method, we fit25 elements from the abundance data set, including 10 heavy neutron-capture elements. We explore the astrophysical origin of the elements in this star through its abundance ratios and component ratios. We find that the contributions from the massive stars played a significant role in the production of light elements in the program star. Our analysis reveals that the heavy neutron-capture elements are produced purely by the main r-process. However, the adopted main r-process model does not adequately fit the observed data, suggesting another main r-process pattern may exist.展开更多
Background The present experiment aimed to evaluate the effects of commercially processed former foodstuffs(cFF)as dietary substitutes of corn,soybean meal and soybean oil on the growth performance,apparent total trac...Background The present experiment aimed to evaluate the effects of commercially processed former foodstuffs(cFF)as dietary substitutes of corn,soybean meal and soybean oil on the growth performance,apparent total tract digestibil-ity(ATTD),hematobiochemical profiles,and liver gene abundance in broiler chickens.Two hundred one-day-old male ROSS-308 chicks were assigned to 4 dietary groups(5 replicates of ten birds per replicate)according to their average body weight(BW,38.0±0.11 g).All groups received a two-phase feeding program:starter,d 1–12 and grower,d 12–33.The control group(cFF0)was fed a standard commercial feed based on corn,soybean meal and soybean oil.The other three groups received diets in which the feed based on corn,soybean meal,and soybean oil was partially replaced with cFF at a substitution level of 6.25%(cFF6.25),12.5%(cFF12.5)or 25%(cFF25)for the following 33 d.Results The growth performance data showed no differences in BW or average daily gain among groups,although the average daily feed intake decreased during the grower period(12–33 d)and over entire experimental period(1–33 d)in a linear manner as the cFF inclusion level rose(P=0.026),positively affecting the gain to feed ratio(P=0.001).The ATTD of dry matter of the cFF-fed groups were greater with respect to control group and increased throughout the experimental period,whereas the ATTD of ether extract linearly decreased with increasing levels of cFF-fed groups compared with control group and throughout the experimental period(P<0.05).Additionally,a lin-ear increase in the heterophil to lymphocyte ratio,serum cholesterol,triglycerides and alanine-aminotransferase were observed with increasing dietary levels of cFF(P<0.05);however,no differences were observed in lipoprotein lipase or sterol regulatory element binding transcription factor gene abundance.Conclusions The results of this experiment demonstrate that it is possible to incorporate cFF into nutritionally balanced diets for broiler chickens,even up to 25%substitution levels,for up to 33 d without adversely impacting the overall growth performance of male broiler chickens raised under commercial conditions.Further studies are essential to validate the hematological trait findings.展开更多
Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and noctu...Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.展开更多
The optical absorption of large molecular compounds HULIS(humic-like substances)can significantly impact the aerosol light absorption and radiative forcing,influencing cloud condensation nuclei formation and thus the ...The optical absorption of large molecular compounds HULIS(humic-like substances)can significantly impact the aerosol light absorption and radiative forcing,influencing cloud condensation nuclei formation and thus the climate and atmospheric environment.This study collected aerosol(PM_(2.5))samples from the summit of Mount Tai in North China to investigate the concentration,molecular composition,and optical properties of HULIS.The average concentration of HULIS in the PM_(2.5) in this study was 1.26±0.54μg/m^(3),comprising for 56%of the water-soluble organic carbon(WSOC),with levels lower than urban areas but higher than other mountainous regions.Mass spectrometry revealed that CHO and CHON components,with high aromaticity and phenolic groups,are major contributors to absorption and fluorescence.These results indicate that HULIS is mainly composed of lignin and proteins/amino sugars,derived from combustion and secondary formation,and possesses a high light absorption capacity(withMAE365(mass absorption efficiency)and AAE(A˚ngstrom exponent)indices of 0.62m^(2)/g and 4.99,respectively).Parallel factor analysis identified three fluorescence components of HULIS,with proportions of 60.8%for less oxygen humic-like substances,21.0%for high oxygen humic-like substances,and 18.2%for protein-like substances.Our study highlights the significance of the light-absorbing capacity and secondary formation of HULIS at Mount Tai,laying the groundwork for investigation into the climate effects,formation mechanisms,and sources of HULIS generation.展开更多
Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressur...Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressure independently of precise ungulate population data.This study aimed to determine the regeneration mechanisms of palatable tree species in natural forest ecosystems by measuring the forage abundance from young trees of focal species and estimating the browsing pressure exerted by ungulates.We analyzed an extensive dataset of 2,838 tree saplings in two national parks in Poland to examine relationships between variables using a zero-intercept linear regression,and multiple linear regression models,and performed parametric and nonparametric tests.We found that the browsing intensity index(BI)is a good predictor of browsing pressure.Both total abundance and twig dry mass loss due to ungulate browsing were more pronounced in shorter saplings,with these effects decreasing as sapling height increased.Picea abies was the most abundant browse source in the Tatra National Park(TNP),whereas Fagus sylvatica dominated in the Roztocze National Park(RNP).Acer pseudoplatanus and Sorbus aucuparia experienced significantly higher browsing pressure in the TNP,whereas Carpinus betulus was more heavily browsed than other species in the RNP.The increase in browse abundance rapidly reduced ungulate browsing pressure on highly palatable tree species.We conclude that despite the high browsing pressure on the palatable species,the contribution of browse from focal species helps to mitigate this pressure and supports their regeneration in the forest canopy.Therefore,this finding provides valuable insights for managing and conserving tree species vulnerable to ungulate browsing in natural forest ecosystems.In addition,the method we used in this study is novel to estimate browsing pressure and assess the recruitment potential of vulnerable tree species;hence,it can be applied in large-scale studies with similar scenarios.展开更多
Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structura...Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.展开更多
The concentration of development projects near protected areas can undermine their conservation objectives.This study examines the impact of such projects on wildlife abundance in Campo-Ma’an National Park(CMNP).Info...The concentration of development projects near protected areas can undermine their conservation objectives.This study examines the impact of such projects on wildlife abundance in Campo-Ma’an National Park(CMNP).Information from the CMNP Conservation Department was analysed to investigate the link between development projects around the park and changes in wildlife populations,and analysis was conducted using statistical tools,including Excel 2020 and SPSS.Pearson’s correlation coefficient was employed to assess the relationship between wildlife abundance indicators and the number of development projects surrounding the park.The findings reveal a significant decline in the abundance of key species,including elephants,great apes(such as gorillas and chimpanzees),and mandrills,over the past decade.Although a brief period of improvement was observed in the early 2010s,these gains were quickly reversed.Overall,the pattern shows that as development activities increased,wildlife numbers tended to decrease.These results underscore the urgent need for stricter regulation of development near the park and for comprehensive environmental and social impact assessments to be conducted before projects commencement.This process must receive greater attention from authorities and stakeholders to regulate activities around national parks and foster conservation efforts.Strengthening this oversight will help to maintain the park’s ecological integrity and promote sustainable conservation.展开更多
Stellar atmospheric parameters and elemental abundances are traditionally determined using template matching techniques based on high-resolution spectra.However,these methods are sensitive to noise and unsuitable for ...Stellar atmospheric parameters and elemental abundances are traditionally determined using template matching techniques based on high-resolution spectra.However,these methods are sensitive to noise and unsuitable for ultra-low-resolution data.Given that the Chinese Space Station Telescope(CSST)will acquire large volumes of ultra-low-resolution spectra,developing effective methods for ultra-low-resolution spectral analysis is crucial.In this work,we investigated the Fully Connected Residual Network(FCResNet)for simultaneously estimating atmospheric parameters(T_(eff),log g,[Fe/H])and elemental abundances([C/Fe],[N/Fe],[Mg/Fe]).We trained and evaluated FCResNet using CSST-like spectra(R~200)generated by degrading LAMOST spectra(R~1800),with reference labels from APOGEE.FCResNet significantly outperforms traditional machine learning methods(KNN,XGBoost,S VR)and CNN in prediction precision.For spectra with the g-band signal-tonoise ratio greater than 20,FCResNet achieves precisions of 78 K,0.15 dex,0.08 dex,0.05 dex,0.10 dex,and0.05 dex for T_(eff),log g,[Fe/H],[C/Fe],[N/Fe]and[Mg/Fe],respectively,on the test set.FCResNet processes one million spectra in only 42 s while maintaining a simple architecture with only 348 KB model size.These results suggest that FCResNet is a practical and promising tool for processing the large volume of ultra-lowresolution spectra that will be obtained by CSST in the future.展开更多
AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the dise...AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.展开更多
To understand the correlations between the abundance of Trichodina spp. and the water quality parameters, the abundance of Trichodina spp. on the gill of yellow catfish in aquaculture water was investigated. Meanwhile...To understand the correlations between the abundance of Trichodina spp. and the water quality parameters, the abundance of Trichodina spp. on the gill of yellow catfish in aquaculture water was investigated. Meanwhile, the temperature and total phosphorus, available phosphorus, total nitrogen, nitrite and ammonia nitro- gen contents of the aquaculture water were measured and determined. The results showed that the abundance of Trichodina spp. on the gill of yellow catfish was negatively correlated with the total phosphorus, available phosphorus and total nitro- gen contents in the aquaculture water, and was positively correlated with the nitrite content in the aquaculture water （P〈0.05）; there were no significant correlations between the abundance of Trichodina spp. and the temperature and ammonia nitrogen content of the aquaculture water （P〉0.05）.展开更多
To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area...To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area, Hainan Island. Mist-nets were operated for a total of 7135 net-hours. A total of 587 individuals of 45 bird species were captured. The total mean capture rate was 8.6 ± 10.4 per 100 net-hours. A total of 4932 individuals of 107 bird species were recorded by visual observation alone and 7616 individuals of 120 species were recorded in a visual and aural combination. The Grey-cheeked Fulvetta (Alcippe morrisonia) was the most abundant species, accounting for 38.7% of total captures, 27.9% of visual observations and 22.2% of visual + aural observations. The capture number was correlated with the number observed. Thirty-one species were more likely to be captured than observed. Canopy species, such as members of the Corvidae and Dicruridae, were seldom captured. For all ground feeding species, the capture number was greater than that of observation. Some cryptic species, such as the Lesser Wren Babbler (Napothera epilepidota), Spotnecked Babbler (Stachyris striolata) and Cuckoo Owl (Glaucidium cuculoides) also had a higher relative capture rate than that of observations. There was a significant relationship between light intensity and the number of birds captured.展开更多
The spatial distribution and species abundance of Pinus tabulaeformis and Quercus liaotungensis Koidz were analyzed with random distribution abundance model and aggregated distribution abundance model,and evaluation g...The spatial distribution and species abundance of Pinus tabulaeformis and Quercus liaotungensis Koidz were analyzed with random distribution abundance model and aggregated distribution abundance model,and evaluation goodness was evaluated based on related information of sample area at 4 hm2 in Shanxi Lingkong Mountain with altitude at 1500-1 800 m.The results showed that of the 30 xylophyta plants,abundance of 20 plants was increasing in sequence and the covered spaces extended accordingly,except of 10 plant species.As pixel area extended,curve of abundance-area tended to be volatile if area in abundance sequence was smaller than that of the front one;the curve tended to be stable if the fluctuating point was removed.For the same species,the higher pixel area is,the larger the covered area of the species in corresponding pixel would be.The results of evaluation goodness indicated that aggregated distribution model is better for prediction on relationship between abundance and area,compared with random distribution abundance model.Both of the two models rely on value of m,namely,number of covered pixel given the pixel is fixed.For the species distribute dispersedly,the prediction results would be more accurate if both of the two models are made use of,or the prediction errors would be larger.Given that the total area of sample plot is fixed,the smaller the pixel area is,the more accurate the prediction would be.展开更多
With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adap...With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adapt to these changes? To elucidate this question,we studied the effect of urbanization on the abundance and distribution of Tree Sparrows in Beijing.We found the abundance of the Tree Sparrow negatively correlated with an urbanization score.Sparrow abundance was very low in residential areas with high-rise buildings,commercial centers and main roads,while their numbers were significantly higher in parks,university campuses,low building residential and suburban areas.Environmental factors within the 50 m and 200 m scales were most suitable in predicting the distribution of Tree Sparrows during winter,while factors within 50 m and 400 m scales are suitable during the breeding season.During winter,the number of conifer trees and pedestrians were the major factors at the 50 m scale,while the area of high-rise buildings and vegetation become the predominant factors on a 200 m scale.Alternatively,during the breeding season the area of low buildings and the number of conifers and pedestrians were the main factors on the 50 m scale while the area of high-rise buildings and vegetation remained the most important factors on the 400 m scale.These results indicate that highly urbanized areas are not suitable habitats for the Tree Sparrow,although this species can adapt to human environments.Food and nest sites for urban birds should be considered in urban planning of big cities in developing countries.展开更多
This paper gives a detailed introduction to the biotic resources in Panxi Area and lists the most typical biotic resources in this area. The authors of this paper adopt the biotic resource abundance evaluation index m...This paper gives a detailed introduction to the biotic resources in Panxi Area and lists the most typical biotic resources in this area. The authors of this paper adopt the biotic resource abundance evaluation index model R1= （S0t -- S1t ） × S1i-1 （i= 1,2,3, …n） to make a quantitative calculation of the biotic resource abundance in this area, and the calculation results show that this area abounds in biotic resources. Through the analysis of the causes of abundant biotic resources in this area, the luxuriant biotic resources in Panxi Area are largely attributed to the complex and varied environment, atrocious climate in history and the introduction of alien species. The purpose of this paper is to point out that biotic resource exploitation is one of the driving forces of economic development in this area, and to emphasize the necessity of biotic resource preservation and its harmonious development with the environment.展开更多
HD 222925 is a rare r-process enhanced star in the Milky Way because of its metal abundance([Fe/H]=-1.46±0.10)and Eu abundance([Eu/Fe]=1.32±0.08).Based on the very complete set of elemental abundances of HD ...HD 222925 is a rare r-process enhanced star in the Milky Way because of its metal abundance([Fe/H]=-1.46±0.10)and Eu abundance([Eu/Fe]=1.32±0.08).Based on the very complete set of elemental abundances of HD 222925,we use the abundance decomposition method to fit the observed abundances of 58elements in the sample star,which is also the largest number of elemental abundances fitted at the same time for a fixed star.We analyze the astrophysical origins of elements in HD 222925 by its abundance ratios and component ratios.It is found that the light elements and the iron group elements in HD 222925 mainly originate from the primary process of the TypeⅡsupernovae(SNeⅡ)with the progenitor mass M>10 M_(⊙)and have no contribution from SNe Ia and the first generation of very massive stars.The contribution of the weak r-process to Ga,Ge,and As is superior to that of the other processes,and its contribution decreases linearly with increasing atomic number.The main r-process that is likely derived from a neutron star merger plays a key role in the formation of neutroncapture elements(Z≥38)in HD 222925.展开更多
Molecular oxygen abundance is a key parameter in understanding the chemical network of the interstellar medium.We estimate the molecular oxygen column density and abundance for a sample of Galactic massive star format...Molecular oxygen abundance is a key parameter in understanding the chemical network of the interstellar medium.We estimate the molecular oxygen column density and abundance for a sample of Galactic massive star formation regions based on observations from the Submillimiter Wave Astronomy Satellite(SWAS)survey.We obtained an averaged O_(2)spectrum based on this sample using the(SWAS)survey data(O_(2),487.249 GHz,N=3-1,J=3-2).No emission or absorption feature is seen around the supposed central velocity with a total integration time of t_(total)=8.67×10^(3)hr and an rms noise per channel of 1.45 m K.Assuming a kinetic temperature T_(kin)=30 K,we derive the 3σupper limit of the O_(2)column density to be 3.3×10^(15)cm^(-2),close to the lowest values reported in Galactic massive star formation regions in previous studies.The corresponding O_(2)abundance upper limit is6.7×10^(-8),lower than all previous results based on SWAS observations and is close to the lowest reported value in massive star formation regions.On a galactic scale,our statistical results confirm a generally low O_(2)abundance for Galactic massive star formation regions.This abundance is also lower than results reported in extragalactic sources.展开更多
Lithium abundances in our Galaxy and especially 6 Li abundances provide important constraints on our understanding of Big Bang Nucleosynthesis(BBNS),stellar evolution and the creation of light elements by cosmic rays ...Lithium abundances in our Galaxy and especially 6 Li abundances provide important constraints on our understanding of Big Bang Nucleosynthesis(BBNS),stellar evolution and the creation of light elements by cosmic rays in the ISM.~6 Li has been detected in energetic solar events,one chromospherically active binary and several dwarf halo stars.Continuing our work on active late-type stars with high lithium abundances,we expand our study to consider if the flare origin of lithium created by spallation can contribute significantly to the Galactic abundance of lithium.We previously derived ~6 Li/~7 Li=0.030 ± 0.010 for active K dwarf GJ 117 using VLT UVES observations.We find^6 Li/~7 Li ratios of 0.02 and 0.10 for two other stars in our sample,GJ 182 and EUVE J1145-55.3 A,respectively.Considering that these later type,active stars have significant flare rates and stellar winds,we have estimated the contribution of these stars to the Galactic lithium abundance.Given that K and M stars comprise over 84% of our Galaxy and that many of these can have significant stellar winds,we conclude that spallation in stellar flares can contribute 1% and up to 5% of the Galactic lithium abundance.展开更多
The variations of environmental abundance and microcystin-LR （MC-LR） production ability of toxic Microcystis in the Nanquan region of Lake Taihu are investigated by real-time quantitative PCR （RTQ-PCR） and high pe...The variations of environmental abundance and microcystin-LR （MC-LR） production ability of toxic Microcystis in the Nanquan region of Lake Taihu are investigated by real-time quantitative PCR （RTQ-PCR） and high performance liquid chromatography （HPLC） from May to December in 2009. Simultaneously, degrees of water pollution and eutrophication are monitored. The results indicate that the water quality in the Nanquan region of Lake Taihu is in a moderate degree of pollution and eutrophication. Algal density exceeds the threshold of bloom from May to November. The environmental abundance of toxic Microcystis is more than 40% from May to October and then significantly declines to 5.66% due to the obvious reduction in the water temperature in December. From May to December, the MC-LR production ability of toxic Microcystis ranges from 1.661 to 9.293 μg/108cells. With the significant drops in water temperature and algal density, the MC-LR production ability of toxic Microcystis is obviously increased from November to December. It is concluded that the lake presents Microcystis bloom and the toxic Microcystis becomes dominant during most of the year. The environmental abundance and the MC-LR production ability of toxic Microcystis have a close relationship with water temperature. The effective control of toxic Microcystis should be considered in both the bloom period and the non-bloom period of winter since the MC-LR production ability of toxic Microcystis obviously increases in winter.展开更多
A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The...A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The average abundance of meiofauna is (1 584± 686) ind./10cm2, with corresponding biomass (dwt) of (1 086±425)!μg/10cm2. The pattern of abundance of meiofauna is similar to the pattern of biomass. There are 65.88% meiofauna in 0￣2 cm sediments, 27.66% in 2￣5 cm sediments and 6.47% in 5￣8 cm sediments. The Spearman correlation analysis between meiofauna and environmental factors shows that abundance of meiofauna, free living ma- rine nematodes, benthic copepods has significant positive correlations with Chl-a. And the abundance of copepods has significant posi- tive correlations with several factors such as Chl-a, Pha-a, Chl-a plus Pha-a and organic matter. A total of 18 meiofauna groups are i- dentified. Nematode is the most dominant group, average abundance (1 404±670) ind/10cm2, accounting for 88.65%, and the follow- ing groups are also important: benthic copepods (5.48%), kinorhyncha (1.26%), polychaeta (1.07%). By biomass, dominant groups are nematodes (51.72%), polychaeta (21.84%), copepods (14.87%), ostracoda (4.92%), kinorhyncha (3.67%). A total of 90 species of ne- matodes are identified. The species composition of nematodes is listed based on selected two stations 7794 (coastal area) and 10694 (cold water mass in deep waters).展开更多
This study aims to explore the distribution of meiofaunal abundance in relation to environmental factors in the Beibu Gulf, a natural semi-enclosed part of the South China Sea, surrounded by China and Vietnam. Meiofau...This study aims to explore the distribution of meiofaunal abundance in relation to environmental factors in the Beibu Gulf, a natural semi-enclosed part of the South China Sea, surrounded by China and Vietnam. Meiofauna and ten benthic environmental factors were determined at 27 sampling stations in the Beibu Gulf in four surveys during 2006 2007. The results show a clear geographical trend in meiofaunal abundance, water depth, salinity and clay content. The meiofaunal abundance and the clay content decreased, whereas the water depth and the salinity increased from the north to the south of the Gulf. The percentage of meiofaunal abundance in the 0 2 cm layer increased, whereas in the 2-5 cm and 5 10 cm layers it decreased from the north to the south of the Gulf. Correlation analysis show significant negative correlations between meiofaunal abundance and water depth, benthic temperature, salinity and pH, but significant positive correlations between meiofaunal abundance and dissolved oxygen, chlorophyll a and clay content.展开更多
基金supported by the National Key Basic R&D Program of China No. 2024YFA1611903the National Natural Science Foundation of China (NSFC, Grant No. 12173013)+2 种基金the project of Hebei provincial department of science and technology under the grant No. 226Z7604Gthe Hebei NSF (No. A2021205006)the China Manned Space Project for funding support of this study
文摘Object LAMOST J020623.21+494127.9(program star) in the thin disk of the Milky Way is reported as a highly r-process-enhanced r-II star with [Eu/Fe] = +1.32 and [Fe/H] =-0.54. The chemical profile of the star reflects the intrinsic composition of the gas cloud present at its birth. Using an abundance decomposition method, we fit25 elements from the abundance data set, including 10 heavy neutron-capture elements. We explore the astrophysical origin of the elements in this star through its abundance ratios and component ratios. We find that the contributions from the massive stars played a significant role in the production of light elements in the program star. Our analysis reveals that the heavy neutron-capture elements are produced purely by the main r-process. However, the adopted main r-process model does not adequately fit the observed data, suggesting another main r-process pattern may exist.
基金Department of Veterinary Sciences“Ricerca Locale–Linea A”.
文摘Background The present experiment aimed to evaluate the effects of commercially processed former foodstuffs(cFF)as dietary substitutes of corn,soybean meal and soybean oil on the growth performance,apparent total tract digestibil-ity(ATTD),hematobiochemical profiles,and liver gene abundance in broiler chickens.Two hundred one-day-old male ROSS-308 chicks were assigned to 4 dietary groups(5 replicates of ten birds per replicate)according to their average body weight(BW,38.0±0.11 g).All groups received a two-phase feeding program:starter,d 1–12 and grower,d 12–33.The control group(cFF0)was fed a standard commercial feed based on corn,soybean meal and soybean oil.The other three groups received diets in which the feed based on corn,soybean meal,and soybean oil was partially replaced with cFF at a substitution level of 6.25%(cFF6.25),12.5%(cFF12.5)or 25%(cFF25)for the following 33 d.Results The growth performance data showed no differences in BW or average daily gain among groups,although the average daily feed intake decreased during the grower period(12–33 d)and over entire experimental period(1–33 d)in a linear manner as the cFF inclusion level rose(P=0.026),positively affecting the gain to feed ratio(P=0.001).The ATTD of dry matter of the cFF-fed groups were greater with respect to control group and increased throughout the experimental period,whereas the ATTD of ether extract linearly decreased with increasing levels of cFF-fed groups compared with control group and throughout the experimental period(P<0.05).Additionally,a lin-ear increase in the heterophil to lymphocyte ratio,serum cholesterol,triglycerides and alanine-aminotransferase were observed with increasing dietary levels of cFF(P<0.05);however,no differences were observed in lipoprotein lipase or sterol regulatory element binding transcription factor gene abundance.Conclusions The results of this experiment demonstrate that it is possible to incorporate cFF into nutritionally balanced diets for broiler chickens,even up to 25%substitution levels,for up to 33 d without adversely impacting the overall growth performance of male broiler chickens raised under commercial conditions.Further studies are essential to validate the hematological trait findings.
文摘Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.
基金supported by the National Natural Science Foundation of China(Nos.22176112 and 42307134)the Natural Science Foundation of Shandong Province(No.ZR2021MD028)the Natural Science Foundation of Qingdao(No.23–2-1–74-zyyd-jch).
文摘The optical absorption of large molecular compounds HULIS(humic-like substances)can significantly impact the aerosol light absorption and radiative forcing,influencing cloud condensation nuclei formation and thus the climate and atmospheric environment.This study collected aerosol(PM_(2.5))samples from the summit of Mount Tai in North China to investigate the concentration,molecular composition,and optical properties of HULIS.The average concentration of HULIS in the PM_(2.5) in this study was 1.26±0.54μg/m^(3),comprising for 56%of the water-soluble organic carbon(WSOC),with levels lower than urban areas but higher than other mountainous regions.Mass spectrometry revealed that CHO and CHON components,with high aromaticity and phenolic groups,are major contributors to absorption and fluorescence.These results indicate that HULIS is mainly composed of lignin and proteins/amino sugars,derived from combustion and secondary formation,and possesses a high light absorption capacity(withMAE365(mass absorption efficiency)and AAE(A˚ngstrom exponent)indices of 0.62m^(2)/g and 4.99,respectively).Parallel factor analysis identified three fluorescence components of HULIS,with proportions of 60.8%for less oxygen humic-like substances,21.0%for high oxygen humic-like substances,and 18.2%for protein-like substances.Our study highlights the significance of the light-absorbing capacity and secondary formation of HULIS at Mount Tai,laying the groundwork for investigation into the climate effects,formation mechanisms,and sources of HULIS generation.
基金funded by Polish National Science Foundation(NCN)(grant No.2018/31/B/NZ8/02786,project title:“How do largescale disturbances influence the relationship between ungulate herbivory and natural regeneration in temperate forests?”)from the Ministry of Science and Higher Education of the Republic of Poland within the framework of statutory activities SUB/040011-D019/2020 of the Department of Forest Biodiversity,University of Agriculture in Krakow.
文摘Herbivorous ungulates are vital elements of forest ecosystems,yet their impact on tree regeneration and forest dynamics is challenging to assess.Despite their significant influence,few studies measure browsing pressure independently of precise ungulate population data.This study aimed to determine the regeneration mechanisms of palatable tree species in natural forest ecosystems by measuring the forage abundance from young trees of focal species and estimating the browsing pressure exerted by ungulates.We analyzed an extensive dataset of 2,838 tree saplings in two national parks in Poland to examine relationships between variables using a zero-intercept linear regression,and multiple linear regression models,and performed parametric and nonparametric tests.We found that the browsing intensity index(BI)is a good predictor of browsing pressure.Both total abundance and twig dry mass loss due to ungulate browsing were more pronounced in shorter saplings,with these effects decreasing as sapling height increased.Picea abies was the most abundant browse source in the Tatra National Park(TNP),whereas Fagus sylvatica dominated in the Roztocze National Park(RNP).Acer pseudoplatanus and Sorbus aucuparia experienced significantly higher browsing pressure in the TNP,whereas Carpinus betulus was more heavily browsed than other species in the RNP.The increase in browse abundance rapidly reduced ungulate browsing pressure on highly palatable tree species.We conclude that despite the high browsing pressure on the palatable species,the contribution of browse from focal species helps to mitigate this pressure and supports their regeneration in the forest canopy.Therefore,this finding provides valuable insights for managing and conserving tree species vulnerable to ungulate browsing in natural forest ecosystems.In addition,the method we used in this study is novel to estimate browsing pressure and assess the recruitment potential of vulnerable tree species;hence,it can be applied in large-scale studies with similar scenarios.
基金supported by the UGent GOA project“Forest biodiversity and multifunctionality drive chronic stress-mediated dynamics in pathogen reservoirs(FORESTER)”(No.BOF20/GOA/009).
文摘Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.
文摘The concentration of development projects near protected areas can undermine their conservation objectives.This study examines the impact of such projects on wildlife abundance in Campo-Ma’an National Park(CMNP).Information from the CMNP Conservation Department was analysed to investigate the link between development projects around the park and changes in wildlife populations,and analysis was conducted using statistical tools,including Excel 2020 and SPSS.Pearson’s correlation coefficient was employed to assess the relationship between wildlife abundance indicators and the number of development projects surrounding the park.The findings reveal a significant decline in the abundance of key species,including elephants,great apes(such as gorillas and chimpanzees),and mandrills,over the past decade.Although a brief period of improvement was observed in the early 2010s,these gains were quickly reversed.Overall,the pattern shows that as development activities increased,wildlife numbers tended to decrease.These results underscore the urgent need for stricter regulation of development near the park and for comprehensive environmental and social impact assessments to be conducted before projects commencement.This process must receive greater attention from authorities and stakeholders to regulate activities around national parks and foster conservation efforts.Strengthening this oversight will help to maintain the park’s ecological integrity and promote sustainable conservation.
基金supported by the National Astronomical Observatories of Chinese Academy of Sciences(No.E4ZR0516)the National Natural Science Foundation of China(12273078,12273075 and 12411530071)+2 种基金support from Royal Society IECNSFC233140 exchange grantFunding for the Project has been provided by the National Development and Reform CommissionFunding for the Sloan Digital Sky Survey IV has been provided by the Alfred P.Sloan Foundation,the U.S.Department of Energy Office of Science,and the Participating Institutions。
文摘Stellar atmospheric parameters and elemental abundances are traditionally determined using template matching techniques based on high-resolution spectra.However,these methods are sensitive to noise and unsuitable for ultra-low-resolution data.Given that the Chinese Space Station Telescope(CSST)will acquire large volumes of ultra-low-resolution spectra,developing effective methods for ultra-low-resolution spectral analysis is crucial.In this work,we investigated the Fully Connected Residual Network(FCResNet)for simultaneously estimating atmospheric parameters(T_(eff),log g,[Fe/H])and elemental abundances([C/Fe],[N/Fe],[Mg/Fe]).We trained and evaluated FCResNet using CSST-like spectra(R~200)generated by degrading LAMOST spectra(R~1800),with reference labels from APOGEE.FCResNet significantly outperforms traditional machine learning methods(KNN,XGBoost,S VR)and CNN in prediction precision.For spectra with the g-band signal-tonoise ratio greater than 20,FCResNet achieves precisions of 78 K,0.15 dex,0.08 dex,0.05 dex,0.10 dex,and0.05 dex for T_(eff),log g,[Fe/H],[C/Fe],[N/Fe]and[Mg/Fe],respectively,on the test set.FCResNet processes one million spectra in only 42 s while maintaining a simple architecture with only 348 KB model size.These results suggest that FCResNet is a practical and promising tool for processing the large volume of ultra-lowresolution spectra that will be obtained by CSST in the future.
文摘AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.
基金Supported by National Natural Science Foundation of China(31402343)Project of Wuhan Academy of Agricultural Science(Cxfzx201503)~~
文摘To understand the correlations between the abundance of Trichodina spp. and the water quality parameters, the abundance of Trichodina spp. on the gill of yellow catfish in aquaculture water was investigated. Meanwhile, the temperature and total phosphorus, available phosphorus, total nitrogen, nitrite and ammonia nitro- gen contents of the aquaculture water were measured and determined. The results showed that the abundance of Trichodina spp. on the gill of yellow catfish was negatively correlated with the total phosphorus, available phosphorus and total nitro- gen contents in the aquaculture water, and was positively correlated with the nitrite content in the aquaculture water （P〈0.05）; there were no significant correlations between the abundance of Trichodina spp. and the temperature and ammonia nitrogen content of the aquaculture water （P〉0.05）.
基金funded by the Kadoorie Farm and Botanical Garden and the Hong Kong Special Administrative Region,China
文摘To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area, Hainan Island. Mist-nets were operated for a total of 7135 net-hours. A total of 587 individuals of 45 bird species were captured. The total mean capture rate was 8.6 ± 10.4 per 100 net-hours. A total of 4932 individuals of 107 bird species were recorded by visual observation alone and 7616 individuals of 120 species were recorded in a visual and aural combination. The Grey-cheeked Fulvetta (Alcippe morrisonia) was the most abundant species, accounting for 38.7% of total captures, 27.9% of visual observations and 22.2% of visual + aural observations. The capture number was correlated with the number observed. Thirty-one species were more likely to be captured than observed. Canopy species, such as members of the Corvidae and Dicruridae, were seldom captured. For all ground feeding species, the capture number was greater than that of observation. Some cryptic species, such as the Lesser Wren Babbler (Napothera epilepidota), Spotnecked Babbler (Stachyris striolata) and Cuckoo Owl (Glaucidium cuculoides) also had a higher relative capture rate than that of observations. There was a significant relationship between light intensity and the number of birds captured.
基金Supported by Monitoring Station of Lingkong Natural Reserve Forest Ecosystem~~
文摘The spatial distribution and species abundance of Pinus tabulaeformis and Quercus liaotungensis Koidz were analyzed with random distribution abundance model and aggregated distribution abundance model,and evaluation goodness was evaluated based on related information of sample area at 4 hm2 in Shanxi Lingkong Mountain with altitude at 1500-1 800 m.The results showed that of the 30 xylophyta plants,abundance of 20 plants was increasing in sequence and the covered spaces extended accordingly,except of 10 plant species.As pixel area extended,curve of abundance-area tended to be volatile if area in abundance sequence was smaller than that of the front one;the curve tended to be stable if the fluctuating point was removed.For the same species,the higher pixel area is,the larger the covered area of the species in corresponding pixel would be.The results of evaluation goodness indicated that aggregated distribution model is better for prediction on relationship between abundance and area,compared with random distribution abundance model.Both of the two models rely on value of m,namely,number of covered pixel given the pixel is fixed.For the species distribute dispersedly,the prediction results would be more accurate if both of the two models are made use of,or the prediction errors would be larger.Given that the total area of sample plot is fixed,the smaller the pixel area is,the more accurate the prediction would be.
基金supported by the National Natural Science Foundation of China (Grant No. 30900181)“111 Project” (2008-B08044)
文摘With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adapt to these changes? To elucidate this question,we studied the effect of urbanization on the abundance and distribution of Tree Sparrows in Beijing.We found the abundance of the Tree Sparrow negatively correlated with an urbanization score.Sparrow abundance was very low in residential areas with high-rise buildings,commercial centers and main roads,while their numbers were significantly higher in parks,university campuses,low building residential and suburban areas.Environmental factors within the 50 m and 200 m scales were most suitable in predicting the distribution of Tree Sparrows during winter,while factors within 50 m and 400 m scales are suitable during the breeding season.During winter,the number of conifer trees and pedestrians were the major factors at the 50 m scale,while the area of high-rise buildings and vegetation become the predominant factors on a 200 m scale.Alternatively,during the breeding season the area of low buildings and the number of conifers and pedestrians were the main factors on the 50 m scale while the area of high-rise buildings and vegetation remained the most important factors on the 400 m scale.These results indicate that highly urbanized areas are not suitable habitats for the Tree Sparrow,although this species can adapt to human environments.Food and nest sites for urban birds should be considered in urban planning of big cities in developing countries.
文摘This paper gives a detailed introduction to the biotic resources in Panxi Area and lists the most typical biotic resources in this area. The authors of this paper adopt the biotic resource abundance evaluation index model R1= （S0t -- S1t ） × S1i-1 （i= 1,2,3, …n） to make a quantitative calculation of the biotic resource abundance in this area, and the calculation results show that this area abounds in biotic resources. Through the analysis of the causes of abundant biotic resources in this area, the luxuriant biotic resources in Panxi Area are largely attributed to the complex and varied environment, atrocious climate in history and the introduction of alien species. The purpose of this paper is to point out that biotic resource exploitation is one of the driving forces of economic development in this area, and to emphasize the necessity of biotic resource preservation and its harmonious development with the environment.
基金supported by the National Natural Science Foundation of China(NSFC)under grants 12173013,11773009the National Key Basic R&D Program of China via 2019YFA0405500+4 种基金W.Y.C.is supported by the“333 talents project”of Hebei Province under the number A202010001supported by the Natural Science Foundation of Hebei Province under grant A2021205006by the project of the Hebei provincial department of science and technology under grant number 226Z7604Gby Scientific Research Project of Hebei Province(ZC2022090)Shijiazhuang University Doctoral Scientific Research Fund Project(21BS014)。
文摘HD 222925 is a rare r-process enhanced star in the Milky Way because of its metal abundance([Fe/H]=-1.46±0.10)and Eu abundance([Eu/Fe]=1.32±0.08).Based on the very complete set of elemental abundances of HD 222925,we use the abundance decomposition method to fit the observed abundances of 58elements in the sample star,which is also the largest number of elemental abundances fitted at the same time for a fixed star.We analyze the astrophysical origins of elements in HD 222925 by its abundance ratios and component ratios.It is found that the light elements and the iron group elements in HD 222925 mainly originate from the primary process of the TypeⅡsupernovae(SNeⅡ)with the progenitor mass M>10 M_(⊙)and have no contribution from SNe Ia and the first generation of very massive stars.The contribution of the weak r-process to Ga,Ge,and As is superior to that of the other processes,and its contribution decreases linearly with increasing atomic number.The main r-process that is likely derived from a neutron star merger plays a key role in the formation of neutroncapture elements(Z≥38)in HD 222925.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11988101 and12041302)the International Partnership Program of the Chinese Academy of Sciences(grant No.114A11KYSB20210010)+5 种基金National Key R&D Program of China No.2023YFA1608004operated by the California Institute of Technology under a contract with the National Aeronautics and Space Administration(80NM0018D0004)the support of the Tianchi Talent Program of Xinjiang Uygur Autonomous Regionthe Collaborative Research Center 1601(SFB 1601 sub-project A2)funded by the Deutsche Forschungsgemeinschaft—500700252support from the University of Cologne and its Global Faculty program。
文摘Molecular oxygen abundance is a key parameter in understanding the chemical network of the interstellar medium.We estimate the molecular oxygen column density and abundance for a sample of Galactic massive star formation regions based on observations from the Submillimiter Wave Astronomy Satellite(SWAS)survey.We obtained an averaged O_(2)spectrum based on this sample using the(SWAS)survey data(O_(2),487.249 GHz,N=3-1,J=3-2).No emission or absorption feature is seen around the supposed central velocity with a total integration time of t_(total)=8.67×10^(3)hr and an rms noise per channel of 1.45 m K.Assuming a kinetic temperature T_(kin)=30 K,we derive the 3σupper limit of the O_(2)column density to be 3.3×10^(15)cm^(-2),close to the lowest values reported in Galactic massive star formation regions in previous studies.The corresponding O_(2)abundance upper limit is6.7×10^(-8),lower than all previous results based on SWAS observations and is close to the lowest reported value in massive star formation regions.On a galactic scale,our statistical results confirm a generally low O_(2)abundance for Galactic massive star formation regions.This abundance is also lower than results reported in extragalactic sources.
基金the California State University NorthridgeDepartment of Physics and Astronomy for support on this project。
文摘Lithium abundances in our Galaxy and especially 6 Li abundances provide important constraints on our understanding of Big Bang Nucleosynthesis(BBNS),stellar evolution and the creation of light elements by cosmic rays in the ISM.~6 Li has been detected in energetic solar events,one chromospherically active binary and several dwarf halo stars.Continuing our work on active late-type stars with high lithium abundances,we expand our study to consider if the flare origin of lithium created by spallation can contribute significantly to the Galactic abundance of lithium.We previously derived ~6 Li/~7 Li=0.030 ± 0.010 for active K dwarf GJ 117 using VLT UVES observations.We find^6 Li/~7 Li ratios of 0.02 and 0.10 for two other stars in our sample,GJ 182 and EUVE J1145-55.3 A,respectively.Considering that these later type,active stars have significant flare rates and stellar winds,we have estimated the contribution of these stars to the Galactic lithium abundance.Given that K and M stars comprise over 84% of our Galaxy and that many of these can have significant stellar winds,we conclude that spallation in stellar flares can contribute 1% and up to 5% of the Galactic lithium abundance.
基金The National Key Technologies R& D Program of Chinaduring the11th Five-Year Plan Period(No.2008ZX07101-011)the National Natural Science Foundation of China(No.30972440)+1 种基金the NaturalScience Foundation of Jiangsu Province(No.BK2008320)the 333 Project Foundation of Jiangsu Province(No.07056)
文摘The variations of environmental abundance and microcystin-LR （MC-LR） production ability of toxic Microcystis in the Nanquan region of Lake Taihu are investigated by real-time quantitative PCR （RTQ-PCR） and high performance liquid chromatography （HPLC） from May to December in 2009. Simultaneously, degrees of water pollution and eutrophication are monitored. The results indicate that the water quality in the Nanquan region of Lake Taihu is in a moderate degree of pollution and eutrophication. Algal density exceeds the threshold of bloom from May to November. The environmental abundance of toxic Microcystis is more than 40% from May to October and then significantly declines to 5.66% due to the obvious reduction in the water temperature in December. From May to December, the MC-LR production ability of toxic Microcystis ranges from 1.661 to 9.293 μg/108cells. With the significant drops in water temperature and algal density, the MC-LR production ability of toxic Microcystis is obviously increased from November to December. It is concluded that the lake presents Microcystis bloom and the toxic Microcystis becomes dominant during most of the year. The environmental abundance and the MC-LR production ability of toxic Microcystis have a close relationship with water temperature. The effective control of toxic Microcystis should be considered in both the bloom period and the non-bloom period of winter since the MC-LR production ability of toxic Microcystis obviously increases in winter.
基金supported by the National Key Basic Research Programs from Ministry of Science and Technology of China under contract Nos G1999043709 and 2002CB412400the National Natural Science Foundation of China under contract No.40176033.
文摘A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The average abundance of meiofauna is (1 584± 686) ind./10cm2, with corresponding biomass (dwt) of (1 086±425)!μg/10cm2. The pattern of abundance of meiofauna is similar to the pattern of biomass. There are 65.88% meiofauna in 0￣2 cm sediments, 27.66% in 2￣5 cm sediments and 6.47% in 5￣8 cm sediments. The Spearman correlation analysis between meiofauna and environmental factors shows that abundance of meiofauna, free living ma- rine nematodes, benthic copepods has significant positive correlations with Chl-a. And the abundance of copepods has significant posi- tive correlations with several factors such as Chl-a, Pha-a, Chl-a plus Pha-a and organic matter. A total of 18 meiofauna groups are i- dentified. Nematode is the most dominant group, average abundance (1 404±670) ind/10cm2, accounting for 88.65%, and the follow- ing groups are also important: benthic copepods (5.48%), kinorhyncha (1.26%), polychaeta (1.07%). By biomass, dominant groups are nematodes (51.72%), polychaeta (21.84%), copepods (14.87%), ostracoda (4.92%), kinorhyncha (3.67%). A total of 90 species of ne- matodes are identified. The species composition of nematodes is listed based on selected two stations 7794 (coastal area) and 10694 (cold water mass in deep waters).
基金The part of the Chinese Offshore Investigation and Assessment Project funded by the State Oceanic Adminis-tration of China
文摘This study aims to explore the distribution of meiofaunal abundance in relation to environmental factors in the Beibu Gulf, a natural semi-enclosed part of the South China Sea, surrounded by China and Vietnam. Meiofauna and ten benthic environmental factors were determined at 27 sampling stations in the Beibu Gulf in four surveys during 2006 2007. The results show a clear geographical trend in meiofaunal abundance, water depth, salinity and clay content. The meiofaunal abundance and the clay content decreased, whereas the water depth and the salinity increased from the north to the south of the Gulf. The percentage of meiofaunal abundance in the 0 2 cm layer increased, whereas in the 2-5 cm and 5 10 cm layers it decreased from the north to the south of the Gulf. Correlation analysis show significant negative correlations between meiofaunal abundance and water depth, benthic temperature, salinity and pH, but significant positive correlations between meiofaunal abundance and dissolved oxygen, chlorophyll a and clay content.
