北京城市代谢预测研究——基于长短期记忆神经网络模型     

刘炳春  齐鑫  王庆山 《地理科学进展》2019,38(6):851-860

城市化进程提升促使城市环境污染加剧、能源消耗激增、人口密度过大等问题的深层次原因在于城市代谢失调。为精准预测北京市城市代谢变化趋势,论文通过能源消费量及人类活动时间指标测算了1980—2016年北京市体外能代谢率,表征城市代谢程度。据此运用长短期记忆神经网络模型(LSTM)预测了2017—2022年北京各部门体外能代谢率。结果表明：① 基于长短期记忆神经网络的城市代谢预测模型精度较高,能够对北京各部门体外能代谢率进行更为精准的预测;② 2017—2022年间,北京第一产业和总体外能代谢率呈下降趋势,其中第一产业在2017年达到峰值,第二、第三产业及生活部门体外能代谢率将呈现增长趋势。③ 除第一、第三产业和总体外能代谢率外,历史变化的时间扰动幅度先小后大。④ 对各部门体外能代谢率EMR_T的影响贡献度最大的因子为第二产业体外能代谢率EMR₂,最小的为第一产业体外能代谢率EMR₁。论文研究结果可为政策制定者优化城市管理方案、提升城市综合实力提供理论依据和决策支持。  相似文献   

Organic matter dynamics and budgets in the turbidity maximum zone of the Seine Estuary (France)     

Josette Garnier  Gilles Billen  Stéphanie Even  Henri Etcheber  Pierre Servais 《Estuarine, Coastal and Shelf Science》2008

Organic matter was studied in the turbidity maximum zone (TMZ) of the Seine Estuary during 8 tidal cycles from April to October in 2001, 2002 and 2003, covering a salinity range from 0 to 27. The hydrological conditions were quite varied (extremely wet in 2001, unusually dry in 2003). A particularly striking feature is the high organic matter content in the suspended solids (SS) of the Seine estuary (4–5%).  相似文献   

Modelling ecosystem functions and properties at different time and spatial scales in shallow coastal lagoons: An application of the LOICZ biogeochemical model     

Gianmarco Giordani  Martina Austoni  José M. Zaldívar  Dennis P. Swaney  Pierluigi Viaroli 《Estuarine, Coastal and Shelf Science》2008

The Land-Ocean Interactions in the Coastal Zone (LOICZ) biogeochemical model (LBM) was applied at different temporal and spatial scales in 17 Italian lagoons of the LaguNet network (http://www.dsa.unipr.it/lagunet). A series of alternative assumptions taking into account benthic vegetation and sedimentary fluxes were introduced and compared with the classical LBM approach at various time scales. The reliability of the LBM application to the seventeen Italian lagoons was tested by comparison to a pool of shallow coastal systems from the global LOICZ database with comparable depths and sizes. The nutrient loads of the Italian sites can be considered relatively low, particularly for dissolved inorganic phosphorus (DIP). Although the median values of estimated internal transformations (source-sink) of both dissolved inorganic phosphorous and nitrogen at the LaguNet sites were comparable with the selected LOICZ sites, the positive and negative extreme values were one order of magnitude lower. Overall, the LBM applications to the Italian sites gave good quality budgets for shallow systems subjected to relatively low nutrient inputs and with a wide range of primary producer communities, including seagrass, macroalgae and phytoplankton. Furthermore, stoichiometry of Carbon:Nitrogen:Phosphorous for the different primary producer groups allowed the integration of previous studies by identifying a series of relationships between nutrient loads and ecosystem functions.  相似文献   

诱导子对海洋真菌Penicillium crustosum 2A4-Z15菌株生物碱代谢的调节作用          下载免费PDF全文

边猛  田黎  张久明  郑立  周俊英  崔志松  林文翰 《海洋学报》2008,30(2):117-123

分别采用4种生物源诱导子和5种非生物源诱导子,对具有较强抑菌活性的海洋真菌壳青霉Penicillium crustosum2A4-Z15菌株进行诱导,考察诱导子对于菌株产生物碱的代谢调节作用。结果表明,不同来源的诱导子对菌株的生物碱产量和生物量影响不同,生物源诱导子的正向调节作用较明显,且其中以细菌源诱导子最为明显。当海洋细菌源诱导子在2A4-Z15菌株发酵对数生长期末,以10μg/cm3的浓度加入时,发酵物生物碱产量最高,较对照提高44.1%。  相似文献   

大弹涂鱼（Boleophthalmus pectinirostris）窒息点及昼夜代谢规律     

曹伏君  郭良珍 《海洋与湖沼》2011,42(6):759-763

在水温25℃时,采用封闭静水式和封闭流水式装置测定了大弹涂鱼的窒息点及其昼夜代谢规律。结果表明,大弹涂鱼的窒息点为0.71mg/L;其标准代谢（SM）和常规代谢（RM）随体质量的增加而降低,不同规格处理组昼夜变化规律相同,即夜间代谢强于白天,但不同处理组SM（F=35.247,P〈0.01）和RM（F=4.679,P〈...  相似文献   

不同条件下凡纳滨对虾(Litopenaeus vannamei)能量代谢研究          下载免费PDF全文

李婷  梁堪富  李义军  王平  孙成志  孙成波 《海洋与湖沼》2011,42(1):41-46

通过设置不同温度、盐度、pH值和摄食状态的方法,研究凡纳滨对虾在不同条件下的无机磷、亚硝酸氮、硝酸氮、氨氮的释放率.结果表明,温度、体重、盐度、pH值和摄食状态对其代谢存在影响.无机磷、亚硝酸氮、硝酸氮、氨氮的释放率与体重呈负相关;在20-30℃的温度范围内,随着温度的上升,凡纳滨对虾磷、亚硝酸氮、氨氮的释放率均上升,...  相似文献   

5. Prebiotic Chemistry – Biochemistry – Emergence of Life (4.4–2 Ga)     

Robert Pascal  Laurent Boiteau  Patrick Forterre  Muriel Gargaud  Antonio Lazcano  Purificación Lopez-Garcia  Marie-Christine Maurel  David Moreira  Juli Pereto  Daniel Prieur  Jacques Reisse 《Earth, Moon, and Planets》2006,98(1-4):153-203

This chapter is devoted to a discussion about the difficulties and even the impossibility to date the events that occurred during the transition from non-living matter to the first living cells. Nevertheless, the attempts to devise plausible scenarios accounting for the emergence of the main molecular devices and processes found in biology are presented including the role of nucleotides at early stages (RNA world). On the other hand, hypotheses on the development of early metabolisms, compartments and genetic encoding are also discussed in relation with their role in extant living organisms. The nature of the Last Common Ancestor is also presented as well as hypotheses on the evolution of viruses. The following sections constitute a collection of independent articles providing a general overview of these aspects.  相似文献   

城市能源利用与CO_2排放的多尺度综合评价(英文)     

张丽君  刘刚军  秦耀辰 《地理学报(英文版)》2014,(4)

Accurate and detailed accounting of energy-induced carbon dioxide(CO2) emissions is crucial to the evaluation of pressures on natural resources and the environment, as well as to the assignment of responsibility for emission reductions. However, previous emission inventories were usually production- or consumption-based accounting, and few studies have comprehensively documented the linkages among socio-economic activities and external transaction in urban areas. Therefore, we address this gap in proposing an analytical framework and accounting system with three dimensions of boundaries to comprehensively assess urban energy use and related CO2 emissions. The analytical framework depicted the input, transformation, transfer and discharge process of the carbon-based(fossil) energy flows through the complex urban ecosystems, and defined the accounting scopes and boundaries on the strength of ‘carbon footprint' and ‘urban metabolism'. The accounting system highlighted the assessment for the transfer and discharge of socio-economic subsystems with different spatial boundaries. Three kinds methods applied to Beijing City explicitly exhibited the accounting characteristics. Our research firstly suggests that urban carbon-based energy metabolism can be used to analyze the process and structure of urban energy consumption and CO2 emissions. Secondly, three kinds of accounting methods use different benchmarks to estimate urban energy use and CO2 emissions with their distinct strength and weakness. Thirdly, the empirical analysis in Beijing City demonstrate that the three kinds of methods are complementary and give different insights to discuss urban energy-induced CO2 emissions reduction. We deduce a conclusion that carbon reductions responsibility can be assigned in the light of production, consumption and shared responsibility based principles. Overall, from perspective of the industrial and energy restructuring and the residential lifestyle changes, our results shed new light on the analysis on the evolutionary mechanism and pattern of urban energy-induced CO2 emissions with the combination of three kinds of methods. And the spatial structure adjustment and technical progress provides further elements for consideration about the scenarios of change in urban energy use and CO2 emissions.  相似文献   

Effect of Dietary Potassium on Growth,Nitrogen Metabolism,Osmoregulation and Immunity of Pacific White Shrimp （Litopenaeus vannamel） Reared in Low Salinity Seawater     

《青岛海洋大学学报(英文版)》2014,(2):311-320

An 8 weeks feeding experiment was conducted to determine the effect of dietary potassium on the growth and physio-logical acclimation of Pacific white shrimp （Litopenaeus vannamei） reared in diluted seawater （salinity 4）. Six semi-purified practical diets containing 0.59, 0.96, 1.26, 1.48, 1.74, and 2.17 g potassium K＋ per 100 g diet were formulated, respectively. The survival and feed conversion rate did not show significant difference among groups of shrimps given these diets （P〉0.05）. The shrimps fed the diets containing 0.96-1.48 g K＋ per 100g diet gained the highest weight, specific growth rate, and protein efficiency ratio. Their ammonium-N excretion rate as well as hemolymph concentration of Na＋ and C1- were significantly lower than those of the control （P〈0.05）, but a reverse trend was observed for their gill Na＋/K＋-ATPase. Moreover, the shrimps fed with 1.48 g K＋ per 100 g diet were the highest in hemolymph urea level, and the phenoloxidase and lysozyme activities were significantly higher than those of the control （P〈0.05）. The growth and physiological response of the test shrimps suggested that diet containing 1.48 g K＋ per 100 g diet improved the growth of L. vannamei in low-salinity seawater, and enhanced the physiological acclimation of the organism.  相似文献   

Effect of dietary potassium on growth,nitrogen metabolism,osmoregulation and immunity of pacific white shrimp (Litopenaeus vannamei) reared in low salinity seawater     

LIU Hongyu  ZHANG Xinjie  TAN Beiping  LIN Yingbo  CHI Shuyan  DONG Xiaohui  and YANG Qihui 《中国海洋大学学报(英文版)》2014,13(2):311-320

An 8 weeks feeding experiment was conducted to determine the effect of dietary potassium on the growth and physiological acclimation of Pacific white shrimp(Litopenaeus vannamei) reared in diluted seawater(salinity 4). Six semi-purified practical diets containing 0.59, 0.96, 1.26, 1.48, 1.74, and 2.17+ g potassium K per 100 g diet were formulated, respectively. The survival and feed conversion rate did not show significant difference among groups of shrimps given these diets(P0.05). The shrimps fed the diets containing 0.96-1.48 g K+ per 100 g diet gained the highest weight, specific growth rate, and protein efficiency ratio. Their ammonium-N excretion rate as well as hemolymph concentration of Na+ and Cl- were significantly lower than those of the control(P0.05), but a reverse trend was observed for their gill Na+/K+-ATPase. Moreover, the shrimps fed with 1.48 g K+ per 100 g diet were the highest in hemolymph urea level, and the phenoloxidase and lysozyme activities were significantly higher than those of the control(P0.05). The growth and physiological response of the test shrimps suggested that diet containing 1.48 g K+ per 100 g diet improved the growth of L. vannamei in low-salinity seawater, and enhanced the physiological acclimation of the organism.  相似文献