生态文明理念下的国土空间均衡：基于两种财富的分析框架     

易家林  郭杰  林津  欧名豪 《地理研究》2022,41(4):945-959

国土空间均衡是生态文明建设与国土空间治理的重要目标。本文首先在“两山”理论与强弱可持续理论的指导下,基于生态财富与物质财富的二分法,探究国土空间均衡的内涵要义及状态评估模型;其次,通过生态财富与物质财富的特性差异及互动机制分析来探讨国土空间均衡的实现机制;最后,基于具体国土空间单元均衡状态的演进分析,研究整体国土空间均衡实现的可行路径。结果显示：① 基于两种财富的国土空间均衡的内涵即人均物质财富以及人均生态财富在空间上的双收敛,且各空间均收敛于较理想的水平值。② 整体性的国土空间均衡状态将会出现“一均衡、三失衡”四种情形。促进两种财富的良性互动,增强协同效应,减少权衡关系,是实现国土空间均衡的关键。③ 国土空间单元的均衡状态可划分为低等均衡或全面失衡、发展失衡、生态失衡、协调均衡四种,促进各具体国土空间单元向高阶均衡状态演进是实现整体国土空间均衡的可行路径。依循两种财富的互动机制与国土空间单元均衡状态的演进规律来指导具体国土空间单元的开发与保护,有利于实现整体的国土空间均衡。  相似文献   

A new identification method for five species of oysters in genus Crassostrea from China based on high-resolution melting analysis   总被引：2，自引：0，他引：2  

王家丰  许飞  李莉  张国范 《中国海洋湖沼学报》2014,32(2):419-425

The high phenotypic plasticity in the shell of oysters presents a challenge during taxonomic and phylogenetie studies of these economically important bivalves. However, because DNA can exhibit marked differences among morphologically similar species, DNA barcoding offers a potential means for oyster identification. We analyzed the complete sequences of the cytochrome oxidase subunit I （COI） of five common Crassostrea species in China （including Hong Kong oyster C. hongkongensis, Jinjiang oyster C. ariakensis, Portuguese oyster C. angulata, Kumamoto oyster C. sikamea, and Pacific oyster C. gigas） and screened for distinct fragments. Using these distinct fragments on a high-resolution melting analysis platform, we developed an identification method that does not rely on species-specific PCR or fragment length polymorphism and is efficient, reliable, and easy to visualize. Using a single pair of primers （Oyster- COI-1）, we were able to successfully distinguish among the five oyster species. This new method provides a simple and powerful tool for the identification of oyster species.  相似文献   

Zooplankton community analysis in the Changjiang River estuary by single-gene-targeted metagenomics     

程方平  王敏晓  李超伦  孙松 《中国海洋湖沼学报》2014,32(4):858-870

DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similarity<96%). Sibling species could also be distinguished. Many species that were overlooked by morphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.  相似文献   

Kilofarms in The Agricultural Heartland     

John Fraser Hart  Mark B. Lindberg 《Geographical review》2014,104(2):139-152

Kilofarms are farms of 1,000 acres or more. The U.S. Department of Agriculture's Census of Agriculture has few tabulations of data by farm size, but geographical analysis suggests some of the characteristics of kilofarms. Their operators are part‐owner farmers. Their land and buildings are worth several millions of dollars, and their gross annual income is well over the $250,000 necessary to provide an acceptable level of living for a contemporary farm family. Kilofarmers concentrate on growing crops of corn and soybeans for cash sale, and they rely on computers and Internet access to help them make marketing decisions.  相似文献   

Impact of Conjugated Shear Joint of “X” Type on Macroscopic Karstification on the Basis of the Analysis of Google Earth Images     

YANG Ruidong  SHENG Xueyong  WEI Xiao  and WEN Xuefeng 《《地质学报》英文版》2012,86(2):520-530

As viewed from space remote-sensing images (e.g. Google Earth images) of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth’s surface is strongly controlled by the Conjugated shear joint of “X” type. Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface, thus, leading to the dissolution of carbonate rocks nearby. As a result, the karst landscape is formed, which is dominated by linear karst valleys. An “X” karst valley network structure appears in the area where horizontal strata are distributed, and a feather-like network structure appears in the area where vertical strata are distributed, respectively. When the water permeates downwards to the underground-water level, it will flow horizontally along the strike of “X” joints toward the local base level of erosion to form an “X” network system of underground conduits in the area where horizontal strata are distributed, but it is relatively complex, because of the joining of other joints. This is the first time we have made use of Google Earth images to study the karst environment. Therefore, it has been successful in research on the Earth’s geomorphology, which could only rely on aerial photos and satellite photos in the past. Google Earth images provide low-cost and applicable imaging materials for the study of Earth’s geomorphology and karst rocky desertification and its control.  相似文献   

非饱和黄土基质吸力的变化     

张楠  计博勋 《吉林地质》2012,31(2):137-142

天然状态下存在大量的非饱和黄土。因此,非饱和黄土中存在的基质吸力在很大程度上可以控制抗剪强度。本次研究的非饱和黄土土样采自中国兰州市,用以展开室内试验,探讨黄土中基质吸力的变化规律以及其脱离含水量的影响因素。结果显示:结构性、矿物成分以及可溶盐含量是控制非饱和黄土基质吸力变化的最重要的三个影响因素。其中,残余含水量和土样密度有相反的相互关系。土样中存在大量的蒙脱石和伊利石的互层(I/S),以及土样中存在的可溶盐也在某种程度上影响着基质吸力的变化。  相似文献   

Enhancement of the benthic communities around an isolated island in the Antarctic Ocean     

Jos&#; I Saiz  Nuria Anad&#;n  Javier Cristobo  Oscar Garc&#;a-Alvarez  Gerardo Garc&#;a-Castrillo  Eduardo L&#;pez  Cruz Palac&#;n  Jes&#;s S Troncoso  Ana Ramos 《海洋学报(英文版)》2013,32(6):47-55

Insular marine biotas are often richer in faunal diversity than those from the open sea in the same geographical region. The existence of particular island effects were tested under polar conditions by comparing infaunal benthic assemblages on Peter I Island with those of similar latitudes in the open ocean at the Bellingshausen Sea and also from the coast of the Antarctic Peninsula. Sampling was carried out aboard the R/V Hespérides during the expedition named BENTART-2003 from 24 January to 3 March 2003. Benthic samples were collected at 18 stations ranging from 90 to 2 044 m depth, using an USNEL-type box corer (BC) dredge. Representatives of 32 higher taxa of invertebrates were found. Univariate and multivariate analyses revealed various patterns in the data. First, significant differences in polychaete abundance were detected between the stations located in the open sea and the remaining sites (island plus mainland sites). Bivalve abundances were also distinct between island and mainland sampling sites. Sediment columns taken from the island seafloor exhibited the highest rate of bioturbation by the infauna. These findings confirm the model that islands develop distinct assemblages characterized by the enhancement of the benthic communities even in cold waters. Several abiotic factors were measured simultaneously at the seafloor and along the water column to investigate faunal distribution patterns. Significant correlations were found between the benthic assemblages and a combination of two environmental variables: "island effect" (measured as a categorical variable) and the redox state of sediments. Richer and more complex benthic assemblages were found in Peter I Island’s sea bottom, whereas the more depauperate bottoms remained in the open sea.  相似文献   

Bianchi Type I string dust cosmological model with magnetic field in general relativity     

Raj Bali  Umesh Kumar Pareek 《Astrophysics and Space Science》2007,312(3-4):305-310

Bianchi Type I string dust cosmological models in presence and absence of magnetic field following the techniques used by Letelier and Stachel, are investigated. To get the deterministic solution, we have assumed that σ ₁¹ is proportional to the expansion (θ) where σ ₁¹ is the eigen value of shear tensor (σ _i ^j ) and which leads to A=N(BC)⁻ⁿ , n>0 where A,B,C are metric potentials and , N and ℓ are constants. The behaviour of the models in presence and absence of magnetic field are discussed. The other physical and geometrical aspects of the model are also discussed.  相似文献   

Elemental abundance analyses with DAO spectrograms: XXXIII. β UMa (A0mA1 IV‐V), α Dra (A0 III), π Dra (A2 IIIs), and κ Cep (B9 III)     

S.J. Adelman  K. Yu  A.F. Gulliver 《Astronomische Nachrichten》2011,332(2):153-158

This paper presents extended analyses of β UMa (A0mA1 IV‐V), α Dra (A0 III), π Dra (A2 IIIs), and κ Cep (B9 III) which have previously been studied in this series. α Dra is a metal‐poor star while κ Cep has solar abundances. Both β UMa and π Dra are Am stars. Whenever possible, more accurate and precise gf values replace older values. High S/N (200+) and high dispersion Dominion Astrophysical Observatory spectrograms to the red of previously obtained spectra supplement the observations. The derived rotational velocities are 45, 25, 26, and 23 km s^–1, respectively. These LTE fine analyses use the ATLAS9 and the WIDTH9 programs of R. L. Kurucz. The results of the extended and the previous analyses are in good agreement. Thus in the past decade a significant improvement in the system of gf values has not been achieved although for many lines there have been changes. The use of additional regions has increased the quality of some results (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

IPCC emission scenarios: How did critiques affect their quality and relevance 1990–2022?     

《Global Environmental Change》2022

Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.  相似文献