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As the floating population has become a vital issue influencing China's economic and social development and aroused broad concern, many scholars have paid attention to the factors that influence settlement intentions of the floating population, while their spatial differences are usually neglected in extant studies. To rectify this situation, this study employs a multi-scale geographically weighted regression model to investigate the spatial pattern of determinants on hukou transfer intentions of the floating population, based on the data of the China Migrants Dynamic Survey in 2016. The results demonstrate that the effects of various determinants present different spatial patterns: part of significance pattern (the average residence time in destination cities, the ratio of rural hukou holders, the number of flows, the ratio of family income to family expenditure, the geographical location), the “East-West” pattern (the ratio of self-employed migrants, the average wage of employed workers), the “Southwest-Northeast” pattern (the ratio of migrants in the secondary industry, the ratio of sharing town employees' social insurance, the ratio of floating population accompanied by children in destination cities, and the population density of municipal districts). Cities of different conditions should formulate different policies that are sensitive to their contexts. 相似文献
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《Netherlands Journal of Sea Research》1979,13(1):99-116
Fine grained material was collected from an extensive North Sea mud field north of 53°30′N. Of one sample deposition and erosion velocities were measured in a series of laboratory experiments using a circular tack in which currents with different speeds could be generated. A series of consolidation periods were applied.The results are compared with tidal current velocity patterns and wave information for the North Sea obtained from published data. It is shown that the boundary between the mud field and the sandy Souther Bight is principally determined by spring tide current velocities. In the mud field net deposition of mud is possible because the increase of erosion velocity by consolidation proceeds faster than the increase of current velocity after slack tide. 相似文献
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Now the appraisement of stock market of China is still in the exploring phases. When stocks are appraised, people usually use expert-method or history-method aiming at different factors, especially the confirming of the factors that affect the stock evaluation and the interaction between different factors are not analyzed quantitatively, resulting in the stagnation of next researches on the whole.By applying the SEM to stock evaluation of Chinese stock market, we build a financial structural model, analyzes the influence to stock evaluation of each factor and build the experience mode value of stock evaluation of China. This can be consulted by stock evaluation and credit evaluation of China. 相似文献
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Estimation of salt tolerance in Andrographis paniculata accessions using multiple regression model 总被引:1,自引:0,他引:1
The complexity and polygenic nature of the salt tolerance trait in plants needs to develop a multiple indicator in the screening process. The mentioned issue led us to carry out an experiment to identify tolerant genotypes through multiple parameters in Andrographis paniculata. For this purpose, the 40-days seedlings were grown in different salinity levels (control, 4, 8, 12 and 16?dS?m?1) on Hoagland??s medium. The results indicated that salinity had a significant effect on the morphological, physiological and biochemical traits. All measured morphological traits, and chlorophyll, K+ and Ca2+ content were significantly decreased with increasing salinity levels, while proline and Na+ content increased. The present exploration revealed that, salt tolerance index (STI), using the multiple regression model, demonstrated a more stable trend than the single variable assay (total dry weight). Furthermore, STI based on multiple regression analysis gives an accurate definition of salt-tolerant individuals. Under salt stress, tolerant accessions had high STI and produced higher proline, K+ and Ca2+, and lower Na+ content than sensitive accessions. Cluster analysis based on related traits to STI, indicated high similarity in each group. These outcomes can be utilized to evaluate the salt tolerance threshold in the species and may have a great advantage over conventional methods. Probably, our upshots can be applied in the next breeding programs to develop salt-tolerant varieties. 相似文献
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While the spatial distribution of foreign aid has aroused a widespread academic interest, the existing research is limited mainly to the transnational level and lacks an analysis of aid allocation within a single recipient country. Moreover, more attention is paid to the factors influencing the aid allocation than to the interactions among different aid allocation stakeholders. To fill the research blank, this paper proposes a “three-party relationship model” to analyze the spatial allocation of aid within a recipient county, and uses the case of Japan's aid to China to validate the model. We find most of the aid has been allocated to the economic infrastructure, over time, and the key aid sector has shifted from economic infrastructure to social infrastructure and general environmental protection; The allocation characteristics of total aid and key aid sectors are various; The spatial allocation pattern of aid reflects an interaction between the donor (Japan) and the recipient country (China). The degree of importance of each aid allocation stakeholder is different at different stages of the total life cycle of aid, and the aid allocation stakeholder relationship in the three-party relationship model may be constantly reshaped during the allocation processes of aid in space. 相似文献
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《Soil Technology》1992,5(3):213-224
The methodology described in this paper provides land evaluators and land use planners with a tool to predict the land production potential for irrigated and rainfed winter wheat in Pinan County (China), taking into account environmental conditions and management practices of the local farmers.The correlation between predicted yields and actual reported yields by local farmers suggests a close resemblance between the simulated production environment and the situation in which the farmers operate.Incorporation in the model of quantified effects of limiting factors on crop performance allows estimation of inputs necessary to improve the actual yield level. 相似文献
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Multiplying possibilities: A postdevelopment approach to hygiene and sanitation in Northwest China
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Kelly Dombroski 《Asia Pacific viewpoint》2015,56(3):321-334
Postdevelopment thinkers and writers have critiqued development discourse for its role in perpetuating inequality. In water, sanitation and hygiene (WASH) literature and interventions, the discourse used perpetuates inequality through classing anything other than private toilets as ‘without sanitation’. This implies that the people who use forms of hygiene and sanitation relying on collective toilets and alternative strategies are somehow unhygienic. Yet residents of Xining (Qinghai Province, China) rely on hygiene assemblages that do not always include private toilets, but nonetheless still work to guard health for families with young children. In this paper, I develop a postdevelopment approach to hygiene and sanitation starting with the place‐based hygiene realities already working to guard health in some way, then working to multiply possibilities for future discursive and material hygiene realities. 相似文献
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Habitation environment suitability and population density patterns in China: A regionalization approach 总被引:1,自引:0,他引:1
The stunning disparity in population density between the southeast and northwest in China is highlighted by the “Hu Line,” a famous population demarcation line proposed by Huanyong Hu in 1935. This research seeks to uncover the underlying physical environment factors that shape such a contrast. Specifically, we propose a habitation environment suitability index (HESI) model to integrate topographic factors, climatic suitability, and hydrological condition into one comprehensive index, and then use a GIS‐automated regionalization method termed REDCAP (Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning) to derive two demarcation lines based on the HESI and population density values, respectively. The two lines that divide China into two regions are largely consistent with each other. The result indicates that the population distribution disparity between the southeast and northwest is largely attributable to the difference in physical environments, and the barrier defined by the Hu Line is here to stay. In addition, the research also explores the (in)consistency between population density and HESI distribution patterns in various regions. 相似文献
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Jiangteng Zhou 《Growth and change》2023,54(2):482-506
This paper examines the impact of highway construction on the size distribution of manufacturing firms using Chinese firm and highway network data. I construct instrumental variables using historical and counterfactual road approaches to identify the causal effects of highway construction. I find that highway construction can increase firm size dispersion and market concentration. Areas near highways have a higher number of firms, more outsourcing activities, and more large firms; while areas further from highways have a higher share of new entry firms. 相似文献
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中国农业工程建设标准体系概述 总被引:2,自引:0,他引:2
研究旨在建立农业工程建设标准体系。运用文献资料查询、专家咨询和研讨等方法,对标准体系框架结构中专业维的划分与组成以及标准体系中标准明细表进行了深入的研究。研究确定农业工程建设标准体系框架结构中专业维包括六大专业27个门类,序列维包括建设过程中12个关键环节、层次维包括4个层次;明细表中包括现行标准173项,在编标准8项,待编标准326项。初步构建了中国农业工程建设标准体系,为农业工程建设标准制修订奠定基础。 相似文献
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中国农村居民点研究进展 总被引:5,自引:2,他引:3
分析了农村居民点研究中主要存在的问题,提出了该领域未来的发展方向,以对农村居民点研究提供参考。研究方法:随着我国社会经济的快速发展,农村居民点发生了一系列变化,大量文献对这种变化进行了阐述,对目前的研究成果进行总结梳理。研究结果:根据农村居民点的研究进展情况,从农村居民点空间结构及其变化、农村居民点演变驱动力机制、城乡一体化过程中有关农村居民点问题、农村居民点土地整理及其他有关农村居民点的研究等五个方面系统地总结农村居民点的研究进展。.研究结论:农村居民点研究的理论体系还需完善,空间分布提取方法有待提高,农村居民点土地整理方法尚需整合。 相似文献
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Regional Consumption Inequality in China: An Oaxaca‐Blinder Decomposition at the Prefectural Level
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Sharp regional differences in income and consumption patterns have characterized the Chinese development process. Focusing on the years 2007 and 2012, this work employs the Oaxaca‐Blinder decomposition to assess the extent and the determinants of the urban/non‐urban and coastal/inland disparity in consumption patterns. The analysis shows that the average gaps across the Chinese prefectures tend to be mainly explained, along both divides, by the mean differences in local endowments of the covariates that explain consumption over GDP ratio. In particular, at the basis of the observed regional disparity, there is an uneven allocation of FDI and foreign enterprises, as well as of domestic investments in fixed assets and welfare state provisions. 相似文献
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《Journal of Landscape Research》2017,(5)
With the development of the aging society in China,the contradiction between the growing old people and the shortage of the elder care community has been increasingly sharp.How to reasonably and effectively establish the elder care community becomes a problem that demanding prompt solution in China.This paper,starting from the most basic constituent factors of the elder care community,namely the concept,the configuration and the service,analyzes 6 types of the concept,redefines the type of the building configuration of the elder care community,and explains the types and levels of the service,which aims to guide the elder care community to deal with the relationship between the 3 factors with a view to providing a reference for the architectural design and standard preparation in the elder care community. 相似文献
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Jaime Prohens Pietro Gramazio Mariola Plazas Hannes Dempewolf Benjamin Kilian María J. Díez Ana Fita Francisco J. Herraiz Adrián Rodríguez-Burruezo Salvador Soler Sandra Knapp Santiago Vilanova 《Euphytica》2017,213(7):158
The need to boost agricultural production in the coming decades in a climate change scenario requires new approaches for the development of new crop varieties that are more resilient and more efficient in the use of resources. Crop wild relatives (CWRs) are a source of variation for many traits of interest in breeding, in particular tolerance to abiotic and biotic stresses. However, their potential in plant breeding has largely remained unexploited. CWRs can make an effective contribution to broadening the genetic base of crops and to introgressing traits of interest, but their direct use by breeders in breeding programs is usually not feasible due to the presence of undesirable traits in CWRs (linkage drag) and frequent breeding barriers with the crop. Here we call for a new approach, which we tentatively call ‘introgressiomics’, which consists of mass scale development of plant materials and populations with introgressions from CWRs into the genetic background of crops. Introgressiomics is a form of pre-emptive breeding and can be focused, when looking for specific phenotypes, or un-focused, when it is aimed at creating highly diverse introgressed populations. Exploring germplasm collections and identifying adequate species and accessions from different genepools encompassing a high diversity, using different strategies like the creation of germplasm diversity sets, Focused identification of germplasm strategy (FIGS) or gap analysis, is a first step in introgressiomics. Interspecific hybridization and backcrossing is often a major barrier for introgressiomics, but a number of techniques can be used to potentially overcome these and produce introgression populations. The generation of chromosome substitution lines (CSLs), introgression lines (ILs), or multi-parent advanced inter-cross (MAGIC) populations by means of marker-assisted selection allows not only the genetic analysis of traits present in CWRs, but also developing genetically characterized elite materials that can be easily incorporated in breeding programs. Genomic tools, in particular high-throughput molecular markers, facilitate the characterization and development of introgressiomics populations, while new plant breeding techniques (NPBTs) can enhance the introgression and use of genes from CWRs in the genetic background of crops. An efficient use of introgressiomics populations requires moving the materials into breeding pipelines. In this respect public–private partnerships (PPPs) can contribute to an increased use of introgressed materials by breeders. We hope that the introgressiomics approach will contribute to the development of a new generation of cultivars with dramatically improved yield and performance that may allow coping with the environmental changes caused by climate change while at the same time contributing to a more efficient and sustainable agriculture. 相似文献
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Heritability of quantitative traits in segregating common bean families using a Bayesian approach 总被引:1,自引:1,他引:0
Maria Celeste Gonçalves-Vidigal Freddy Mora Thaís Souto Bignotto Roxelle Ethienne Ferreira Munhoz Lara Daniela de Souza 《Euphytica》2008,164(2):551-560
Genetic parameters for six quantitative traits in the early generation of segregating populations of common beans (Phaseolus vulgaris L.) were evaluated. A Bayesian approach was used for estimating the variance components, breeding values and broad sense
heritability of the quantitative traits under analysis. The Markov Chain Monte Carlo method was utilized to analyze the contribution
of genes affecting complex traits. Twenty-four F3 families were evaluated in the field during 2005 in Santa Catarina, southern Brazil. With regard to the grain yield and yield
components, the additive variances were relatively similar to the dominance variances. This result is confirmed by the 95%
credible set from the posterior distribution. The mean estimates of broad-sense heritability (H2) varied from 11.5% to 64.2%. The heritability estimates of yield and yield components were higher than the estimates for
the number of days until flowering and reproductive period. However, for grain yield, the 95% heritability credible set included
the heritability estimates from point of crop duration. The predicted genetic gain reached the highest value for the number
of pods per plant (10.95%). Days to flowering and reproductive period had the lowest values of genetic advance. One hundred
seed-weight, grain yield and seeds per pod exhibited a similar predictable level of genetic gain: GA = 5.73%, 5.81% and 4.77%,
respectively. The Bayesian framework provided information that is useful for a breeding program, since it contributes to the
understanding of how quantitative traits are genetically controlled. 相似文献
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Many spectral indices have been proposed to derive plant nitrogen (N) nutrient indicators based on different algorithms. However, the relationships between selected spectral indices and the canopy N content of crops are often inconsistent. The goals of this study were to test the performance of spectral indices and partial least square regression (PLSR) and to compare their use for predicting canopy N content of winter wheat. The study was conducted in cool and wet southeastern Germany and the hot and dry North China Plain for three winter wheat growing seasons. The canopy N content of winter wheat varied from 0.54% to 5.55% in German cultivars and from 0.57% to 4.84% in Chinese cultivars across growth stages and years. The best performing spectral indices and their band combinations varied across growth stages, cultivars, sites and years. Compared with the best performing spectral indices, the average value of the R2 for the PLSR models increased by 76.8% and 75.5% in the calibration and validation datasets, respectively. The results indicate that PLSR is a potentially useful approach to derive canopy N content of winter wheat across growth stages, cultivars, sites and years under field conditions when a broad set of canopy reflectance data are included in the calibration models. PLSR will be useful for real-time estimation of N status of winter wheat in the fields and for guiding farmers in the accurate application of their N fertilisation strategies. 相似文献