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1.
PLoS One ; 18(5): e0286248, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37256864

RESUMO

Under the background of global urbanization, the continuous expansion and extensive utilization of urban and rural construction land has caused a large amount of arable land to be occupied, which seriously threatens national food security. This paper describes the spatio-temporal patterns of urban and rural construction land expansion and its occupation of arable land by using the urban and rural construction land expansion intensity, the urban and rural construction land expansion intensity difference index, and geo-detector model. It also explores the mechanisms through which the arable land was occupied. Results showed that construction land in both urban and rural areas expanded over the period 2009-2018 despite a large number of rural and urban migrants, and the major contributor to the rapid urbanization in China. This dual expansion could mainly be attributed to the tendency of these migrants to keep or even enlarge their rural construction land, which also resulted in a severer arable land loss than that caused by the expansion of urban construction land. Second, the rate of arable land occupied by urban and rural construction land in Henan province has been gradually slowing down, whereas the expansion of rural construction land is most dependent on arable land occupation. Third, according to the geo-detector model, the relationship between urbanization level and arable land occupied by urban and rural construction was the strongest, followed by the growth rate of fixed asset investment and the proportion of secondary and tertiary industries in GDP.


Assuntos
Indústrias , Urbanização , Humanos , China , População Rural , Ocupações , Conservação dos Recursos Naturais/métodos , Cidades
2.
Artigo em Inglês | MEDLINE | ID: mdl-36900843

RESUMO

The countryside is a complex regional system with population and land as the core elements, and it is of great significance to study the coordination of the rural human-land relationship for promoting rural ecological protection and high-quality development. The Yellow River Basin (Henan section) is an important grain-producing area with dense population, fertile soil, and rich water resources. Based on the rate of change index and Tapio decoupling model, this study took county-level administrative region as the evaluation unit to explore the characteristics of the spatio-temporal correlation model of rural population/arable land/rural settlements in the Yellow River Basin (Henan section) from 2009 to 2018 and the optimal path of coordinated development. The results show the following: (1) The decrease of rural population, the increase of arable land in a relatively large part of non-central cities, the decrease of arable land in central cities, and the general increase in the area of rural settlements are the most important characteristics of the Yellow River Basin (Henan section) for the change of rural population/arable land/rural settlements. (2) There are spatial agglomeration characteristics of rural population changes, arable land changes, and rural settlements changes. Areas with a high degree of change in arable land have a certain degree of spatial consistency with areas with a high degree of change in rural settlements. (3) The type of T3 (rural population and arable land)/T3 (rural population and rural settlement) is the most important temporal and spatial combination mode, and rural population outflow is serious. In general, the spatio-temporal correlation model of rural population/arable land/rural settlements in the eastern and western sections of the Yellow River Basin (Henan section) is better than that in the middle section. The research results are helpful to deeply understand the relationship between rural population and land in the period of rapid urbanization and can provide reference for the classification and sub-standard policies of rural revitalization. It is urgent to establish sustainable rural development strategies for improving the human-land relationship, narrowing the rural-urban disparity, innovating rural residential land area policies, and revitalizing the rural area.


Assuntos
Rios , População Rural , Humanos , Urbanização , Solo , Desenvolvimento Sustentável , China , Conservação dos Recursos Naturais/métodos
3.
Artigo em Inglês | MEDLINE | ID: mdl-33672829

RESUMO

The significant spatial heterogeneity among river basin ecosystems makes it difficult for local governments to carry out comprehensive governance for different river basins in a special administrative region spanning multi-river basins. However, there are few studies on the construction of a comprehensive governance mechanism for multi-river basins at the provincial level. To fill this gap, this paper took Henan Province of China, which straddles four river basins, as the study region. The chord diagram, overlay analysis, and carbon emission models were applied to the remote sensing data of land use to analyze the temporal and spatial patterns of carbon storage caused by land-use changes in Henan Province from 1990 to 2018 to reflect the heterogeneity of the contribution of the four basins to human activities and economic development. The results revealed that food security land in the four basins decreased, while production and living land increased. Ecological conservation land was increased over time in the Yangtze River Basin. In addition, the conversion from food security land to production and living land was the common characteristic for the four basins. Carbon emission in Henan increased from 134.46 million tons in 1990 to 553.58 million tons in 2018, while its carbon absorption was relatively stable (1.67-1.69 million tons between 1990 and 2018). The carbon emitted in the Huai River Basin was the main contributor to Henan Province's total carbon emission. The carbon absorption in Yellow River Basin and Yangtze River Basin had an obvious spatial agglomeration effect. Finally, considering the current need of land spatial planning in China and the goal of carbon neutrality by 2060 set by the Chinese government, we suggested that carbon sequestration capacity should be further strengthened in Yellow River Basin and Yangtze River Basin based on their respective ecological resource advantages. For future development in Hai River Basin and Huai River Basin, coordinating the spatial allocation of urban scale and urban green space to build an ecological city is a key direction to embark upon.


Assuntos
Carbono , Ecossistema , China , Cidades , Humanos , Rios
4.
J Photochem Photobiol B ; 205: 111842, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32146274

RESUMO

Development of high responsive photocatalysts for the degradation of dye from water is a significance method to solve the difficulties of water contamination. In the present project, Cr2O3 nanoparticles were decorated onto cellulose through a facile synthesis method, which was exposed to characterization by XRD, FESEM, DLS, PL, and UV-vis spectroscopy. The structural attributes confirmed the presence of rhombohedral phase of Cr2O3 nanoparticles. The mean crystal size of Cr2O3, and Cr2O3/cellulose nanocomposites were 38.50 nm, and 50.11 nm, respectively. The band gap values (Eg) of Cr2O3, and Cr2O3/cellulose nanocomposites were was found 3.00, and 2.53 eV, respectively. Moreover, the morphological and optical studies have been showed the impressive photocatalytic properties of the prepared Cr2O3/cellulose nanocomposites. The photocatalytic efficiency of Cr2O3, and Cr2O3/cellulose nanocomposites has been investigated for the photo-degradation of crystal violet in the ultraviolet light region. The Cr2O3/cellulose indicated promising photocatalytic performance and up to 99.65% of the crystal violet was photo-degraded in 40 min. The obtained crystal violet degradation results were fitted onto a Langmuir-Hinshelwood (L-H) plot. The antioxidant performances of Cr2O3, and Cr2O3/cellulose were analyzed. The beneficial antibacterial performance of the Cr2O3/cellulose nanocomposites was tested by various bacteria as Escherichia coli, Pseudomonas aeruginosa, staphylococcus aurous, and Streptococcus pyogenes.


Assuntos
Antibacterianos , Antioxidantes , Celulose , Compostos de Cromo , Nanocompostos , Antibacterianos/administração & dosagem , Antibacterianos/química , Antioxidantes/administração & dosagem , Antioxidantes/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Compostos de Bifenilo/química , Catálise , Celulose/administração & dosagem , Celulose/química , Compostos de Cromo/administração & dosagem , Compostos de Cromo/química , Corantes/química , Violeta Genciana/química , Nanocompostos/administração & dosagem , Nanocompostos/química , Picratos/química , Poluentes Químicos da Água/química
5.
Exp Ther Med ; 7(6): 1591-1594, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24926349

RESUMO

The aim of the present study was to determine the effect of different concentrations of mitomycin C (MMC) administered intraoperatively during laser-assisted subepithelial keratectomy (LASEK) surgery. A total of 261 patients (496 eyes) were randomly divided into two groups: 0.04% MMC treatment group consisting of 133 patients (245 eyes) and the 0.02% MMC treatment group consisting of 128 patients (251 eyes). The MMC solutions were dropped intraoperatively onto the ablation region and the duration was dependent on the preoperative refractive power of the patient's cornea: ≤-3.00 diopters (D), 30 sec; between -3.25 D and -6.00 D, 60 sec; between -6.25 D and -9.00 D, 90 sec and ≥-9.25 D, 110 sec. Postoperative observations included haze formation, visual acuity, changes in refractive power, corneal endothelial cell density and incidence of complications. The one year postoperative incidence of haze differed significantly between the groups (P<0.05). The one week and one year comparisons of postoperative visual acuity also differed significantly between the groups (P<0.05). Postoperative changes in corneal refractive power at one, six and 12 months following surgery significantly differed between the groups (P<0.05). No statistically significant difference was identified between the density of corneal endothelial cells prior to surgery and the density at one, six and 12 months following surgery (P>0.05). Thus, the intraoperative application of 0.04% MMC solution effectively inhibited haze formation and markedly improved the efficacy of LASEK surgery, when compared with that of 0.02% MMC.

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