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Study of primordial deuterium abundance in Big Bang nucleosynthesis 被引量:1
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作者 Zhi-Lin Shen Jian-Jun He 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第3期208-215,共8页
Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium... Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent reactions.To date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational precision.In this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium abundance.We found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H uncertainty.Currently,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He rate.From the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d. 展开更多
关键词 Big Bang nucleosynthesis abundance of deuterium Reaction cross section Reaction rate Monte Carlo method
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Molecular Oxygen Abundance in Galactic Massive Star Formation Regions Based on SWAS Observations
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作者 Bing-Ru Wang Di Li +9 位作者 Paul F.Goldsmith Jingwen Wu Chao-Wei Tsai Donghui Quan Xia Zhang Junzhi Wang Gary J.Melnick Jin-Zeng Li Gary A.Fuller Jinjin Xie 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第9期83-98,共16页
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
关键词 ism:molecules galaxies:abundances ism:lines and bands Galaxy:abundances
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The Impact of Nova Outbursts on the Chemical Abundance of the Interstellar Medium
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作者 Guoli He Chunhua Zhu +4 位作者 Guoliang Lü Lin Li Sufen Guo Helei Liu Jun Gao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第10期116-129,共14页
Nova outbursts are the results of thermonuclear runaways,which occur when sufficient material accretes on the surfaces of white dwarfs(WDs).Using the MESA code,we construct a detailed grid for carbon-oxygen and oxygen... Nova outbursts are the results of thermonuclear runaways,which occur when sufficient material accretes on the surfaces of white dwarfs(WDs).Using the MESA code,we construct a detailed grid for carbon-oxygen and oxygen-neon-magnesium novae.By employing population synthesis methods,we conduct a statistical analysis of the distribution of novae in the Milky Way.In our models,on average,a typical nova system may undergo about8000 eruptions and the Galactic nova rate is~130 yr^(-1).The C,N,and O elements in nova ejecta are strongly affected by the mixing degree between WD core and accreted material.Our results show that the average value of^(12)C/^(13)C in nova ejecta is about an order of magnitude lower than that on the surface of a red giant,that for^(16)O/^(17)O is about 5 times lower,and that for^(14)N/^(15)N is about 1.5 times lower.The annual yields of^(13)C,^(15)N,and^(17)O from nova ejection are larger than those from AGB stars.This indicates that compared to a red giant,nova eruptions are a more important source of the odd-numbered nuclear elements of^(13)C,^(15)N,and^(17)O in the Galactic interstellar medium. 展开更多
关键词 ism:abundances (stars:)novae cataclysmic variables (stars:)white dwarfs
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Small temporal variation in abundance of virioplankton compared to bacterioplankton and phytoplankton in two bays in the northern South China Sea
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作者 Jiandong ZHANG Yineng LI +1 位作者 Lijuan LONG Sijun HUANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第4期1130-1142,共13页
Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China Sea.The two coastal regions exhibited different variation patterns in physicochemical p... Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China Sea.The two coastal regions exhibited different variation patterns in physicochemical parameters.Moreover,the diel variations of picoplankton groups were different between the two bays.The abundance of the picoplankton in Sanya Bay displayed a pronounced diel variation,while it was not significant in Daya Bay.In addition,some similar patterns of picoplankton abundance were discovered.In the two bays,virioplankton exhibited the smallest fluctuation range,whereas picocyanobacteria fluctuated most markedly.The fluctuation range of picoplankton groups was larger in spring tide than in neap tide,especially in Sanya Bay.Random forest model analysis demonstrated that the variation of picoplankton groups was attributed to physical and chemical factors in Sanya Bay and Daya Bay,respectively.Therefore,our findings suggest that virioplankton abundance can persist more stably in response to changing environmental conditions compared to bacterioplankton and picophytoplankton. 展开更多
关键词 diel variation abundance picoplankton group VIRIOPLANKTON PICOCYANOBACTERIA
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Diversity, Abundance and Distribution Patterns of Epibenthic Echinoderms in Dungonab Bay, Red Sea, Sudan
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作者 Abdelmoneim Karamalla Gaiballa 《Open Journal of Ecology》 2024年第4期366-380,共15页
The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square met... The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square metre belt transects along each permanent line transect at 20 metre intervals were used to collect data. The data were subjected to univariate and multivariate analyses. Spatial variations of epibenthic echinoderm abundance were assessed with one-way analysis of variance. Hierarchical agglomerative clustering was used to identify and illustrate the similarities in echinoderm abundance between line transects and between belt transects. Indices of richness (d), diversity (H'), evenness (J') and dominance (C) were used to explain the diversity of epibenthic echinoderm species. The distribution pattern of each echinoderm species was determined in each permanent line transect. A total of 986 individuals were recorded within sixteen species of epibenthic echinoderms in the four line transects. Holothuriidae was the dominant family (5 species and 342 individuals). The most abundant echinoderms species was Pearsonothuria graeffei (77 individuals, about 7.81%). Abundances intra-transects and intra-families were insignificant (f = 1.67, p = 0.183, df = 3 and f = 3.24, p = 0.083, df = 9, respectively). The highest values of Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef species richness index (d), and Simpson Dominance index (C) were 2.738, 0.9875, 2.791 and 0.07159, respectively. The distribution patterns of all species in the study transects varied between clumped and uniform, with the exception of Asthenosoma varium of the Echinothuridae family, which had clumped distribution patterns in all transects. The study concluded that Dungonab Bay supports rich and diverse communities of epibenthic echinoderms. 展开更多
关键词 SUDAN Red Sea ECHINODERM DIVERSITY abundance and Distribution
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Seasonal Abundance and Diversity of Birds of Prey and Owls in Al Wathba Wetland Reserve in Abu Dhabi, UAE
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作者 Shakeel Ahmed Salim Jáved +3 位作者 Shahid B. Khan Eissa Al Hammadi Abdullah Al Hammadi Nouf Sameer Alqadi 《Open Journal of Ecology》 2024年第3期228-244,共17页
Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 20... Inland wetlands in Abu Dhabi Emirate are wintering and stopover sites for migratory birds of prey. We conducted long-term regular monitoring surveys in Al Wathba Wetland Reserve (AWWR) from January 1995 to December 2022. Both diurnal and occasionally nocturnal surveys were undertaken to record the migratory raptors and owls in the Wetland Reserve. During the study, a total of 1282 regular monitoring visits were undertaken and 27 species of diurnal raptors and owls representing five families and three orders were detected. These represent 57% of the total species of birds of prey recorded in the UAE. Overall, 63% of all the species that we observed were Accipitriformes followed by 26% Falconiformes and 11% Strigiformes. We found that changes in mean daily temperature have a positive effect on raptor species diversity and abundance in the Wetland Reserve. The species encounter rate was higher in low temperature as compared to high temperature and overall regression equation was statistically significant F (4, 1126) = 8.49), p = 0.00). However, the numbers of raptors did not vary significantly across the years (p = 0.51). Western Marsh-harrier (Circus aeruginosus) and Greater Spotted Eagle (Clanga clanga) were recorded to be the most abundant species in the wetland reserve followed by Common Kestrel (Falco tinnunculus). However, the encounter rate of globally threatened Greater Spotted Eagle was detected to have significantly decreased since 2016. Moreover, 63% of the species detected were uncommon and rarely recorded such as 1) Saker Falcon 2) Lanner Falcon 3) Long-eared Owl & Merlin, which were the rare records from the wetland reserve. Furthermore, 27 years of regular monitoring in the wetland have yielded diverse diurnal raptors and owl fauna (H) = 0.83, (E) = 1.43 (Shannon Diversity Index). The results demonstrate that long-term monitoring surveys in arid environments are essential to determine the trends in the raptor populations and to document rare and globally important species. 展开更多
关键词 Wetland Reserve RAPTORS abundance DIVERSITY Abu Dhabi Inland Wetland AWWR Greater Spotted Eagle
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Evaluating the Impacts of Human Activities on Diversity, Abundance, and Distribution of Large Mammals in Nimule National Park, South Sudan
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作者 Abdallah Gordon Shazali Joseph Mayindo Mayele +1 位作者 Joel Emmanuel Saburi Jubara Nadlin 《Open Journal of Ecology》 2024年第5期483-507,共25页
Globally, human activities have a significant impact on the diversity, abundance, and distribution of large mammals in Protected Areas (PAs). These disturbances increase human pressure on biodiversity and species habi... Globally, human activities have a significant impact on the diversity, abundance, and distribution of large mammals in Protected Areas (PAs). These disturbances increase human pressure on biodiversity and species habitats, highlighting the need for conservation. This study aimed to assess the abundance and distribution of large mammals in different habitat types within Nimule National Park (NNP) and understand the impacts of human activities on them. Data on the abundance and distribution of large mammals and their respective habitat types were collected through line transect surveys. Human activity signs were observed and recorded along the transect lines. To estimate the impacts of human activities on the diversity, abundance, and distribution of large mammal species, as well as to identify any significant differences between them and their habitat types, the study utilized the Kruskal Wallis test, Polynomial multiple regressions, and diversity indices. The findings from the Shannon-Weiner and Simpson indices indicated that large mammal species were more diverse inside the park (H’ = 1.136;D = 0.570) compared to the buffer zone (H’ = 0.413;D = 0.171), with 85% (443 out of 510 samples) recorded within Nimule National Park. The species abundance showed a semi-balanced status (0.58). The diversity results among different habitat types revealed that large mammals were more diverse and highly distributed in both open woodlands (244) and dense woodlands (192), while riverine vegetation had the lowest diversity (8). Statistical tests demonstrated a highly significant difference at a 99% confidence interval (p-value = 0.01) between habitat types and identified species of large mammals. Additionally, the results highlighted the high abundance of Uganda kob (274), baboons (141), and warthog (57) across most habitat types, accounting for at least 75% of their distribution. The most prevalent human activities observed were cattle footprints (27%) and cattle dung (14%). Human footprints and tree cutting combined accounted for 9%, indicating the practice of livestock grazing, poaching, encroachment, and fuelwood collection by local communities. However, these activities did not appear to significantly impact the diversity, abundance, and distribution of large mammals in Nimule National Park. Therefore, it is crucial to foster shared responsibilities and engage relevant stakeholders in the management and conservation of large wildlife species. Regular community awareness programs should be implemented to cultivate a sense of ownership. Moreover, it is recommended that a comprehensive survey be conducted on the population status of all mammal species in Nimule National Park, including its surrounding Buffer Zone. Monitoring the impact of human activities on their behavior and habitats using satellite images should also be carried out at least every five to ten years. 展开更多
关键词 Diversity of Large Mammals abundance and Distribution IMPACTS Biodiversity Conservation Human Activities Nimule National Park South Sudan
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Abiotic Factors Associated with Abundance Dynamics and Antibiotic Multidrug Resistance of Escherichia coli and Enterococcus faecalis Isolated from Some Ombessa Aquatic Systems (Central Cameroon Region)
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作者 Lucie Leme Banock Blandine Pulchérie Tamatcho Kweyang +3 位作者 Fabrice Ezo’o Mengo Stephane Arthur Noah Eric Donald Mbo Zang Olive Vivien Noah Ewoti 《Journal of Geoscience and Environment Protection》 2024年第9期335-369,共35页
The present study conducted in the town of Ombessa aims to assess the influence of abiotic factors on the abundance dynamics and antibiotic susceptibility of Escherichia coli and Enterococcus faecalis isolated from so... The present study conducted in the town of Ombessa aims to assess the influence of abiotic factors on the abundance dynamics and antibiotic susceptibility of Escherichia coli and Enterococcus faecalis isolated from some aquatic systems from February to July 2022, monthly samples were taken at 10 water points used by the population (8 groundwater points and 2 surface water points). Samples were analyzed for physico-chemical parameters such as temperature, pH, electrical conductivity. Bacteriological variables such as BHAM, E. coli and E. faecalis abundances were also assessed. Antibiotic susceptibility of E. coli and E. faecalis was assessed using 06 antibiotics using the Kirby-Bauer diffusion disk method. The results show that bacterial abundances were the highest in surface waters. Bacterial densities were the highest in May and the lowest in February. The average densities recorded were 3845 CFU/100mL for BHAM, 380 CFU/100mL for E. coli and 14 CFU/100mL for E. faecalis in groundwater;and 8583 CFU/100mL for BHAM, 6878 CFU/100mL for E. coli and 812 CFU/100mL for E. faecalis in surface water. Antibiotic susceptibility tests showed that these bacterial species are sensitive to Gentamicin, Chloramphenicol, Azithromycin and Ciprofloxacin. They are all resistant to Trimethoprim/Sulfamethoxazole, E. coli is resistant to Doxycycline and E. faecalis has an intermediate sensitivity to Gentamicin. Overall, the Multiresistance to Antibiotics (MRA) indices obtained were above 0.2, indicating the presence of multidrug resistance in bacterial communities. The physico-chemical properties of the water varied over time and space, but on the whole remained below the threshold values of WHO guidelines. The degree of linkage between abiotic water variables and bacteriological parameters has shown that bacterial densities are more abundant in rainy seasons and increased O2 levels favor bacterial growth, while TSS, CO2 and dissolved nitrate levels affect the sensitivity of these bacterial species to antibiotics. 展开更多
关键词 Bacterial abundance MULTIRESISTANCE ABIOTIC AQUATIC
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Fish Assemblage and Abundance Distribution in Nanji Islands Marine Nature Reserve in Relation to Season Change
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作者 Cheikh Sarr Cungen Yu +2 位作者 Ousmane Ndiaye Hamet Diadhiou Ngor Ndour 《Journal of Agricultural Chemistry and Environment》 2024年第1期13-32,共20页
The fishing survey station located in the warm waters of the East China Sea is one of the abundant fishery resources of waters;with a large number of economic fish breeding grounds and economic juvenile feeding ground... The fishing survey station located in the warm waters of the East China Sea is one of the abundant fishery resources of waters;with a large number of economic fish breeding grounds and economic juvenile feeding grounds. Several fish species according to this bottom trawl survey results which appear in the annual survey from winter to autumn give us a total of 58 species, which have appeared throughout the year. But the vast majority of species appears only in certain seasons, according to the sea fish survey and based on seasonal migratory species or species mainly small endemic species. The survey of fish is tropical and subtropical warm water species and warm temperate species, and the history of the area has several types of 397 different species. There are many reasons, in addition to recent years, human disturbance and adverse consequences of environmental changes brought about, but also with the relevant sampling methods and sampler time, the survey sampled only trawl based, from Ping yang Ocean and Fisheries Bureau, the waters are still other jobs method net, gill nets, fishing industry, etc. Survey results show that the type of fish in the summer (58 species) > spring (55 species) > winter (51 species) > autumn (42 species). The type of season was among spring to summer rose, summer to autumn decline. The survey found that in the reef area of the Nanji Islands, no one species of fish is the dominant species throughout the year (according to the dominant species, each species is dominant only in one season). From the dominant species turnover accounting for the four seasons, in winter it has 53.72% of the total biomass or annual biomass, spring it has 41.53% of the overall biomass, summer it has 31.85% and autumn it has 38.56% of total biomass. Visible, seasonal succession of dominant species of fish phenomenon is very obvious, especially in the spring and winter, summer transfers dominate species at this stage show the greatest change, but winter, the transfer of this dominant species changes in minimal. Seasonal changes from biomass and the average annual marine fish survey biomass were 4832.25 g/h. From different seasons, the average biomass in winter (10779.88 g/h) > of the average biomass in spring (3624.1 g/hour) > of the mean biomass in autumn (3158 g/h) > the average Biomass in summer (1767 g/h). All of them show significant seasonal variation of the biomass, in winter and spring, the biomass is generally not high, but significantly higher than in the summer and autumn seasons. Each season, around the coast of southern Zhejiang, is less than the biomass and other catches off, which involves investigating sea location, size range, and the survey ship different network related tools. Another change from the area of biomass, some studies found that the survey of four-season fish of waters above the biological capacity of several kilograms only in some stations, namely stations and the highest biomass in summer appeared in stations 3, 7 and 11. In autumn the highest biomass appeared in stations 3, 6, 20 and 23. 展开更多
关键词 Nanji Islands Species Composition abundance Distribution SEASONS
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Impacts of bird abundance, activity height and light intensity on the number of birds captured by mist netting 被引量:2
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作者 邹发生 陈桂珠 杨琼芳 《Chinese Birds》 2010年第4期221-229,共9页
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
关键词 activity height bird abundance light intensity mist nets point counts
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Effect of urbanization on the abundance and distribution of Tree Sparrows (Passer montanus) in Beijing 被引量:3
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作者 张淑萍 郑光美 《Chinese Birds》 2010年第3期188-197,共10页
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
关键词 URBANIZATION Tree Sparrow (Passer montanus) abundance DISTRIBUTION BEIJING
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基于DEMATEL-ISM的公共设施可持续设计提升策略研究 被引量:2
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作者 易西多 刘颖 《包装工程》 CAS 北大核心 2024年第2期25-35,共11页
目的 为探索可持续设计需求在公共设施设计中的重要性问题,准确全面地推进公共设施的可持续设计,构建覆盖公共设施生命全周期的多指标设计体系模型,对设计阶段前期的因素重要性需求及相关性进行评估。从而支持在后续的公共设施设计过程... 目的 为探索可持续设计需求在公共设施设计中的重要性问题,准确全面地推进公共设施的可持续设计,构建覆盖公共设施生命全周期的多指标设计体系模型,对设计阶段前期的因素重要性需求及相关性进行评估。从而支持在后续的公共设施设计过程中的可持续设计评估。方法 以可持续设计的环境价值、经济价值和社会价值为目标层,对美景度、环保度等9个影响因素进行分析,获取公共设施在可持续设计方面的各种影响因素,构建研究体系。在此基础上,提出运用DEMATEL-ISM组合模型探究各制约因素间的复杂影响关系,利用排序和重要性结果,寻找关键要素,绘制层级关系示意图,使各种因素之间的关系更加条理化、层次化。根据计算结果提出有助于在设计阶段提高公共设施设计可持续的策略及建议。结果 研究表明,在公共设施的可持续设计中,实用度和可控度的中心度最高,为重要的影响因素。公共设施可持续设计需要以提高美景度及和谐度为改善基础,实用度、可控度和体验度为调节因素,最终通过控制环保度、耐久度等因素,保障公共设施设计的可持续运行。结论 基于DEMATEL-ISM可以直观清晰地展现公共设施可持续设计影响因素之间的相互关系。通过对模型信息的理性分析,能够促使后期设计方案在公共设施生命全周期的各个维度上具有可持续性,并在理论层面为设计环节的决策提供参考依据。 展开更多
关键词 DEMATEL ism 可持续设计 公共设施 影响因素
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Correlation Analysis between Abundance of Trichodina spp. and Water Quality Parameters
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作者 张立强 李媛 +4 位作者 魏朝晖 邓平 丁桂珍 李勤 艾桃山 《Agricultural Science & Technology》 CAS 2017年第7期1318-1321,共4页
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
关键词 Trichodina spp. abundance Total phosphorus Total nitrogen NITRITE Ammonia nitrogen
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基于集成DEMATEL-ISM的民航飞行安全风险影响因素研究 被引量:1
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作者 徐佳 刘宗芹 +1 位作者 周卓丹 林雍雅 《科技和产业》 2024年第6期200-206,共7页
航空安全是民航发展的生命线,飞行安全风险研究是飞行安全分析的重要内容,飞行安全风险影响因素的研究是飞行安全风险研究的重要基础。为研究民航飞行安全风险影响因素,在构建飞行安全风险评价指标体系的基础上,采用决策式实验分析法和... 航空安全是民航发展的生命线,飞行安全风险研究是飞行安全分析的重要内容,飞行安全风险影响因素的研究是飞行安全风险研究的重要基础。为研究民航飞行安全风险影响因素,在构建飞行安全风险评价指标体系的基础上,采用决策式实验分析法和解释结构模型联合法(decision-making trial and evaluation laboratory-interpretative structural modeling method,DEMATEL-ISM)的算法构建飞行安全风险影响因素模型,对因素的属性、重要度、作用机理等进行深入分析,建立系统性的多级递阶结构模型。最后通过算例编程仿真实现,对结果深入分析与研究,探讨其实际应用价值,证明该方法的可行性和有效性,该方法可以为飞行安全风险管理提供决策帮助和理论指导,有助于提升飞行安全管理水平。 展开更多
关键词 飞行安全风险 飞行安全风险影响因素 DEMATEL ism 集成DEMATEL-ism
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基于DEMATEL-ISM模型的地铁火灾疏散影响因素研究 被引量:3
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作者 孟晓静 马欢 《工业安全与环保》 2024年第1期40-44,共5页
为减少地铁火灾事故对人员及财产安全的威胁,提升地铁火灾疏散安全性,对地铁火灾疏散影响因素进行系统性研究。在构建地铁火灾疏散影响因素指标体系的基础上,将决策实验室分析法(DEMATEL)与解释结构模型(ISM)联合,用于研究各因素对地铁... 为减少地铁火灾事故对人员及财产安全的威胁,提升地铁火灾疏散安全性,对地铁火灾疏散影响因素进行系统性研究。在构建地铁火灾疏散影响因素指标体系的基础上,将决策实验室分析法(DEMATEL)与解释结构模型(ISM)联合,用于研究各因素对地铁火灾疏散系统的重要程度,并对各因素间的逻辑结构进行梳理分析。结果表明,恐慌心理和火灾产物分别为影响地铁火灾疏散系统安全性的关键性直接因素和根本因素,24个地铁火灾疏散影响因素可划分为3层5阶的递阶结构。此研究有助于科学认识地铁火灾疏散系统,对提高实际疏散安全性具有参考价值。 展开更多
关键词 地铁火灾 人员疏散 影响因素 DEMATEL模型 ism模型
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家庭农场数字农业技术采纳作用机制——基于ISM-MICMAC模型分析 被引量:1
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作者 周妮笛 纪丽彤 +1 位作者 舒澍成 杨菲 《科技管理研究》 CSSCI 2024年第1期117-123,共7页
为探究家庭农场数字农业技术采纳作用机制,通过构建技术采纳影响因素体系,利用ISM-MICMAC模型得出各层次因素、驱动力-依赖性矩阵。ISM层次模型表明,技术安全性感知是直接表层因素,社会网络、设备操作能力、家庭收入、耕地面积、组织化... 为探究家庭农场数字农业技术采纳作用机制,通过构建技术采纳影响因素体系,利用ISM-MICMAC模型得出各层次因素、驱动力-依赖性矩阵。ISM层次模型表明,技术安全性感知是直接表层因素,社会网络、设备操作能力、家庭收入、耕地面积、组织化程度、土地细碎化程度、是否参加培训、技术有用性感知和技术易用性感知是中层间接因素,家庭农场主的政治身份、受教育程度、年龄、家庭劳动力人数、居住地理位置、政府宣传引导、政府经济补贴和基础设施是深层本质因素,对技术采纳起决定性作用;驱动力-依赖性矩阵表明,家庭农场主政治身份、受教育程度属高驱动力、低依赖性独立因素。据此提出完善数字基础设施、强化宣传推广、开展教育培训和增加政策扶持等对策。 展开更多
关键词 数字农业技术 技术采纳 影响因素 ism MICMAC
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基于DEMATEL-ISM的水利工程EPC项目价值增值机理研究 被引量:4
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作者 俞洪良 杨正涵 +1 位作者 徐铨彪 潘益斌 《浙江大学学报(理学版)》 CAS CSCD 北大核心 2024年第1期120-130,共11页
采用设计-采购-施工(engineering-procurement-construction,EPC)总承包模式的水利工程项目日益增多,研究其价值增值机理有利于总承包方做好项目的价值管理。从水利工程EPC项目的价值链分析入手,基于文献和专家访谈得到23个价值增值影... 采用设计-采购-施工(engineering-procurement-construction,EPC)总承包模式的水利工程项目日益增多,研究其价值增值机理有利于总承包方做好项目的价值管理。从水利工程EPC项目的价值链分析入手,基于文献和专家访谈得到23个价值增值影响因素。采用问卷调查方式得到各因素间的影响程度评分,用决策实验和评估实验(decision-making trial and evaluation laboratory,DEMATEL)法计算了各因素的中心度和原因度,结合解释结构模型(interpretative structural modeling,ISM)对数据进行分析,将价值增值因素划分为6类,构建了水利工程EPC项目价值增值的递阶模型,探究和揭示了项目价值增值的路径和机理。研究结果对水利工程EPC总承包方制订管理策略有一定启示作用。 展开更多
关键词 水利工程 设计-采购-施工(EPC)总承包 价值增值 决策实验和评估实验-解释结构模型(DEMATEL-SIM)
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基于ISM和AHP的城乡结合部公众突发公共卫生事件风险感知关键影响因素分析 被引量:1
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作者 黄敏 陈嘉淇 《安全与环境工程》 CAS CSCD 北大核心 2024年第3期47-53,64,共8页
深入研究城乡结合部公众突发公共卫生事件风险感知关键影响因素,对政府调节公众风险感知、提升应急管理能力具有重要意义。首先构建城乡结合部公众突发公共卫生事件风险感知影响因素指标体系,然后利用解释结构模型(ISM)方法对影响因素... 深入研究城乡结合部公众突发公共卫生事件风险感知关键影响因素,对政府调节公众风险感知、提升应急管理能力具有重要意义。首先构建城乡结合部公众突发公共卫生事件风险感知影响因素指标体系,然后利用解释结构模型(ISM)方法对影响因素进行层次分析,并采用层次分析(AHP)法对各层次影响因素的影响力大小进行分析,确定城乡结合部公众突发公共卫生事件风险感知的关键影响因素。结果表明:城乡结合部公众突发公共卫生事件风险感知的影响因素分为直接因素、间接因素和根本因素三个层次;应急决策指挥和感染死亡情况是关键直接影响因素,医疗救援能力和应急物资保障是关键间接影响因素,文化水平、技能水平和公共设施完善度是关键根本影响因素。针对关键影响因素,提出建立和完善预警系统、普及宣传应急知识和加大对城乡结合部地区医疗机构的投入等措施,为政府应急管理提供决策支持。 展开更多
关键词 城乡结合部 突发公共卫生事件 风险感知 关键影响因素 解释结构模型(ism) 层次分析法(AHP)
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结合STPA和DEMATEL-ISM的民机起落架收放系统风险研究 被引量:1
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作者 贾宝惠 韩文瑞 +2 位作者 肖海建 高源 陈怡凡 《安全与环境学报》 CAS CSCD 北大核心 2024年第8期2885-2894,共10页
为从系统整体角度完成对起落架收放系统的风险辨识和影响分析,将系统理论过程分析(Systematic Theory Process Analysis,STPA)与决策实验室分析-解释结构模型(Decision Making Trial and Evaluation Laboratory Interpretive Structural... 为从系统整体角度完成对起落架收放系统的风险辨识和影响分析,将系统理论过程分析(Systematic Theory Process Analysis,STPA)与决策实验室分析-解释结构模型(Decision Making Trial and Evaluation Laboratory Interpretive Structural Modeling,DEMATEL-ISM)相结合来开展分析。首先,定义事故和系统级危险,以民机进近阶段放下起落架为例,运用STPA完成对风险因素的系统化辨识;其次,基于最大平均熵减(Maximum Mean De-entropy,MMDE)算法帮助DEMATEL-ISM模型确定阈值,完成对风险因素影响的重要性分析并识别可能引发系统级危险的风险传递路径,据此挖掘关键致因场景,以给出风险预防建议。结果显示:线路性能退化或失效、位置作动控制组件(Position Action Control Unit,PACU)核心处理器故障为关键原因因素,收放作动筒作动异常、机组成员操作不当、起落架指示灯显示异常、起落架液压选择阀作动异常、PACU信息接收有误为关键结果因素,这些因素均涉及多条可能引发系统级危险的风险传递路径,应予以重点控制。 展开更多
关键词 安全工程 起落架收放系统 系统理论过程分析(STPA) 决策实验室分析法(DEMATEL) 解释结构模型(ism) 关键因素 风险传递路径
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我国高校大数据治理能力成熟度模型的构建与实践——基于CMM与ISM融合研究的视角
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作者 胡水星 包飞宇 +1 位作者 荆洲 王会军 《远程教育杂志》 CSSCI 北大核心 2024年第4期22-30,共9页
构建科学有效的高校大数据治理评价模型,对激活大数据在教育数字化转型中的核心驱动作用,发挥高校在教育数字化转型中的引领示范作用具有重要意义。基于此,基于高校大数据治理的核心要素,通过融合解释结构模型(ISM)和能力成熟度模型(CMM... 构建科学有效的高校大数据治理评价模型,对激活大数据在教育数字化转型中的核心驱动作用,发挥高校在教育数字化转型中的引领示范作用具有重要意义。基于此,基于高校大数据治理的核心要素,通过融合解释结构模型(ISM)和能力成熟度模型(CMM)两种研究方法,以ISM的层次结构划分逻辑、核心要素在层次结构中的分布情况等量化手段,强化在CMM构建过程中,划分成熟度等级、确定关键过程域、明晰成熟度等级和关键过程域的对应关系等主要环节的科学性与合理性,构建出包括5个成熟度级别、21项关键过程域在内的我国高校大数据治理能力成熟度模型。同时,基于2022年浙江省高校信息化建设评估项目数据,采取分层抽样法抽取30所高校开展模型的实践应用,以期为高校大数据治理评价研究提供参考。 展开更多
关键词 高校大数据治理 评价模型 ism CMM
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