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1.
Artigo em Inglês | MEDLINE | ID: mdl-33401753

RESUMO

Infectious diseases have caused some of the most feared plagues and greatly harmed human health. However, despite the qualitative understanding that the occurrence and diffusion of infectious disease is related to the environment, the quantitative relations are unknown for many diseases. Zika virus (ZIKV) is a mosquito-borne virus that poses a fatal threat and has spread explosively throughout the world, impacting human health. From a geographical perspective, this study aims to understand the global hotspots of ZIKV as well as the spatially heterogeneous relationship between ZIKV and environmental factors using exploratory special data analysis (ESDA) model. A geographically weighted regression (GWR) model was used to analyze the influence of the dominant environmental factors on the spread of ZIKV at the continental scale. The results indicated that ZIKV transmission had obvious regional and seasonal heterogeneity. Population density, GDP per capita, and landscape fragmentation were the dominant environmental factors affecting the spread of ZIKV, which indicates that social factors had a greater influence than natural factors on the spread of it. As SARS-CoV-2 is spreading globally, this study can provide methodological reference for fighting against the pandemic.


Assuntos
Infecção por Zika virus , Animais , Humanos , Mosquitos Vetores , Análise Espaço-Temporal , Zika virus , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/transmissão
2.
Front Immunol ; 11: 1717, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33013823

RESUMO

Vascular endothelial injury caused by post-hemorrhagic shock mesenteric lymph (PHSML) return is an important manifestation during refractory hemorrhagic shock. Using human umbilical vein endothelial cells (HUVECs) and transcriptome analysis, this study sought to investigate the molecular mechanism underlying the adverse effect of PHSML on vascular endothelium. Post-hemorrhagic shock mesenteric lymph was collected from male rats after they underwent hemorrhagic shock and following resuscitation, while normal mesenteric lymph (NML) was harvested from sham rats. Human umbilical vein endothelial cells were incubated with the culture medium containing either 10% phosphate buffered saline (Control), NML, or PHSML for 3 h, and then were harvested for RNA sequencing. In comparison with NML treated cells, 37 genes were differentially expressed in PHSML-treated HUVECs, including 32 upregulated genes and five downregulated genes. These differentially expressed genes were mainly enriched in inflammatory pathways, including signaling pathways for activation of the NOD-like receptors, NF-κB, and TNF. Furthermore, we found that C-C motif chemokine ligand 2 (CCL2) was increased significantly after PHSML treatment, and Bindarit, a CCL2 production inhibitor, attenuated the damage of HUVECs induced by PHSML. The results provide molecular evidence on vascular endothelium damage caused by PHSML. C-C motif chemokine ligand 2 might represent a new target for reducing vascular injury after severe hemorrhagic shock.

3.
Ambio ; 49(12): 2015-2025, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32488572

RESUMO

Ecosystems respond to climatic and anthropogenic forcings with regime shifts and reorganizations of their system structures. In river basins, changes in sediment transport can have cascading effects that cause ecosystem regime shifts. The Yellow River, once the world's most sediment-rich river, has experienced dramatic regime shifts. Although recent intervention has returned sediment discharge in the Yellow River to pristine levels, our understanding of previous regime shifts remains inadequate, particularly for the regime shift to a sediment rich period during early historical time. We reanalyzed previous datasets to clarify the first historical sediment transport regime shift in the Yellow River. Our results show that while historical climatic changes (e.g., the Medieval Warm Period, about 900-1100 AD) caused changes in sediment transport, a regime shift occurred only under increased forcing from anthropogenic stresses (started from about 1350 AD, reached the tipping point after 1900 AD). This unique behavior of the Yellow River under increasing anthropogenic forces may provide perspective for sustainable river basin management.


Assuntos
Ecossistema , Rios , China , Monitoramento Ambiental , Sedimentos Geológicos
5.
Sci Total Environ ; 714: 136792, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32018969

RESUMO

Urban heat island (UHI) effect is an important ecological consequence of rapid urbanization. Although the spatio-temporal evolution of urban heat islands (UHIs) and their driving forces have been discussed in previous studies, the accurate identification of the spatial morphology and connectivity of UHIs is currently lacking. Taking Beijing City as an example, the radius approach (RA) was applied to identify the thresholds of UHIs, and multiple indexes were calculated to analyze the changing connectivity of UHIs from 2000 to 2015. The results showed that the UHIs in Beijing City formed archipelagos, which composed of single main heat island that occupied >79.85% of the total area, and small heat islands scattered in the centers of surrounding districts. In 15 years, the total area occupied by UHIs increased by 30.04%, indicating that the UHI effect became worse. As for landscape patterns of UHIs, aggregation index (AI) increased by 1.6%, landscape shape index (LSI) decreased by 4.1%, and probability of connectivity (PC) increased by 69.1%, all indicating that the distribution of UHIs became more compact, and the connectivity between islands increased. Different expansion types had different influences on the landscape patterns of UHIs: the edge-expansion reduced the fragmentation of UHIs and increased connectivity between islands, the infilling expansion made the boundaries of UHIs regular, and the leapfrog expansion made the AI slight decrease. Based on the radius approach, identifying the range of multi-center UHIs and their spatial expansion type can provide an effective planning guideline for mitigating the negative UHI effect.

6.
Ambio ; 49(1): 245-257, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30852776

RESUMO

The dramatic increase in anthropogenic activity severely threatens the biodiversity and life-support services that underpin human well-being. The broadened focus of protecting ecosystem services (ESs) better aligns the interests of people and biodiversity conservation. In this study, we used species richness as a surrogate for biodiversity and mapped the key ESs in East Africa with the goal to assess the spatial congruence between biodiversity and ESs, and evaluate the representation of current protected areas (PAs) network for biodiversity and ESs. The results showed that PAs well represented for species richness and regulating services but underrepresented for provisioning services. The PAs network occupies 10.96% of East Africa's land surface, and captures 20.62-26.37% of conservation priorities for vertebrate and plant species. It encompasses more than 16.23% of priority areas for three regulating services, but only 6.17% and 5.22% for crop and livestock production, respectively. Strong correlations and high overlaps exist between species richness and regulating services, particularly for carbon storage, water yield and plants. Thus, we believe that actions taken to conserve biodiversity also will protect certain ESs, which in turn will create new incentives and funding sources for the conservation of biodiversity. Overall, our results have wide-ranging policy implications and can be used to optimize conservation strategies for both biodiversity and multiple ESs in East Africa.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , África Oriental , Biodiversidade , Carbono , Humanos
7.
Bioresour Technol ; 297: 122387, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31735696

RESUMO

This work developed a novel two-stage bioprocess for electricity generation from bakery waste (BW). In the first stage, commercial glucoamylase was utilized to hydrolyze the BW to produce soluble BW hydrolysate. It was found that 100 g BW could be converted to 32 g hydrolysis solid and 760 mL BW hydrolysate. The highest glucose production of 21.9 g/L could be achieved within 5 h. In the second stage, the soluble BW hydrolysate was utilized as feedstock for electricity generation in microbial fuel cell (MFC). The maximum voltage of 0.386 V was obtained. The power density reached a peak value of 29.96 mW/m2 when the external resistance was 1090 Ω. It could be potentially utilized to transform high-starch containing raw materials into biofuels production which could reduce the cost of biofuels production effectively for industrial application.


Assuntos
Fontes de Energia Bioelétrica , Biocombustíveis , Eletricidade , Glucana 1,4-alfa-Glucosidase , Hidrólise
8.
Sci Total Environ ; 705: 135853, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31818570

RESUMO

Plantations can significantly improve the ecological environment of arid areas. However, in the arid area of Northwestern China, plantations consume several thousand cubic meters of water per hectare per year, which also has a negative effect. By evaluating the relationship between the supply and demand of ecosystem services, the positive and negative benefits of plantations can be effectively identified for regional sustainable development. This study took typical arid regions as examples and evaluated the changes in ecosystem services before and after the conversion of a desert shrub system to a plantation system based on emergy analysis. The relationship between the supply and demand of various ecosystem services from different stakeholder perspectives was investigated and combined with the degree of ecosystem service demand obtained from the participatory survey. Results showed the following. (1) The ecosystem services provided by vegetation increased, the ecosystem services provided by water resources decreased, and the total service decreased by 6.89E+17 sej. (2) The relationship between the supply and demand of ecosystem services provided by water resources was of the "low-high" type. Dust purification was of the "high-high" type, and carbon sequestration and soil conservation were of the "high-low" type. (3) From the perspective of citizens, the matching degrees of the supply and demand of dust purification and soil conservation services were 21.75% and 9.38% higher than those of farmers, respectively. From the perspective of farmers, the matching degrees of the supply and demand of water supply, water purification, power supply and sediment transport, and carbon sequestration were 9.90%, 10.96%, 3.22%, and 18.28% higher than those of citizens, respectively. In summary, attention should be given to the efficient use and conservation of water resources and the promotion of the coordinated development of ecosystem services by comparing the differences in matching degrees of supply and demand among different stakeholders when constructing plantations. Meanwhile, the distribution of water resources should be given attention to protect the water demand of citizens in a targeted manner for effectively improving the level of regional well-being.

9.
Sci Total Environ ; 769: 144297, 2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33486176

RESUMO

Understanding the impacts of climate change and human activities on vegetation is of great significance to the sustainable development of terrestrial ecosystems. However, most studies focused on the overall impact over a period and rarely examined the time-lag effect of vegetation's response to climatic factors when exploring the driving mechanisms of vegetation dynamics. In this study, we identified key areas driven by either positive or negative human activities and climate change. Taking the three karst provinces of southwest China as the case study area, a Leaf Area Index (LAI)-climate model was constructed by quantifying the time-lag effect. Then the associated residual threshold was calculated to identify the vegetation change areas dominated by human activities and climate change. The results showed that, during the implementation period of ecological restoration projects from 1999 to 2015, positive impact areas of human activities were mainly distributed among the implementation areas of ecological restoration projects, accounting for 5.61% of the total area. For another, the negative impact areas were mainly distributed across the mountainous area of Yunnan Province, accounting for 1.30% of the total area. Karst landform had the greatest influence on the areas dominated by positive human activities, whereas both topography and karst landform significantly affected the areas dominated by negative human activities. Urban development level had the greatest impact on the areas dominated by climate change. The outcomes of this study provided scientific supports for the sustainable development of ecological restoration projects in China's karst region.

10.
J Environ Manage ; 251: 109615, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31581043

RESUMO

Rapid environment change and urbanization process have profoundly altered the socio-ecological relationships and influenced on how local residents perceive ecosystem services (ES) and human well-being (HW). However, the quantified socio-cultural valuation of rural-urban comparison is still insufficient. In this study, we investigated the perception on provisioning, regulating, and cultural ES importance and HW satisfaction degree of basic materials, health, security, and social relations. Subsequently, we explored the linkages between and within ES and HW by face-to-face interviews with urban and rural residents. The results showed that rural residents valued more genetic resources, flood regulation, erosion regulation, and aesthetics ES, while urban residents gave high importance to wood & fiber ES. Overall, urban residents valued provisioning ES, while rural residents valued regulating ES. No difference was observed in cultural ES. For HW, rural residents felt more satisfied with security and health, while urban residents were more satisfied with basic materials. We observed strong relationships among provisioning and regulating ES in rural and urban communities, and the same was observed as in health and security HW. Principal component analysis (PCA) results showed the different variable associations in rural ES and urban HW as well as different groups in urban ES and rural HW. Through confirmation factor analysis (CFA), we screened out freshwater, water purification, air purification, and cultural value as dominant ES indicators for rural and urban population according to the framework of Millennium Ecosystem Assessment in Yanhe watershed. The assessment of people's perception can contribute to the integration of socio-cultural values into the policymaking process.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , China , Ecologia , Humanos , População Rural
11.
Sci Total Environ ; 697: 134103, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31476500

RESUMO

The thinking of landscape sustainability discussed the win-win goal of landscape management for both ecological conservation and social development. The China-proposed Belt and Road Initiative has a pathway of green development towards sustainability, which could be benefited from a corporation on transnational landscape management. Although previous remote sensing observations showed that the ecosystem improvement and social development can coexist in most of the Belt and Road region, whether the change tendencies can be sustained have been neglected. Based on the continuous vegetation index, nighttime light and landcover datasets between 1980s-2010s, a detailed observation of the landscape evolution was obtained in this study. Depending on the identifications of temporal breakpoints, the time series was separated to identify the former and latter tendencies, and the evolution score were evaluated. The results showed that the vegetation greening trend weakened in nearly half of the region, and the arid region mostly experienced vegetation browning lately. The evolution patterns of ecological landscape and social landscape were coincided distributed in China and India, and in Southeast Asia was not scored high for both ecological conservation and social development. Consequently, we should not be overly optimistic about the synergy between ecosystem improvement and social development.


Assuntos
Conservação dos Recursos Naturais/métodos , Ecossistema , Mudança Social , Transportes , Ecologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-31484402

RESUMO

Facing the demands of biodiversity conservation and ecosystem service improvement, the spatial pattern optimization of nature reserves has always been a research topic of interest. However, there remains a lack of methodological guidance in the planning of nature reserves and the surrounding areas. To promote the landscape sustainability of nature reserves, we constructed ecological security patterns (ESPs) with two scenarios as a case study in Wenchuan, China. In detail, the ecological sources were identified by ecosystem service evaluation, and the resistance surface was characterized by the habitat quality. The ecological corridors were determined based on circuit theory and the minimum cumulative resistance model. The ecological sources were mainly aggregated in the protected areas, with an area of more than 1000 ha; the high-resistance values were mainly in the area with dense roads or high elevation. There were 21 corridors in the scenario of only optimizing the nature reserve, while 31 corridors were identified when considering non-nature reserves, and the landscape connectivity was enhanced accordingly. The result supported constructing the ESPs between nature and non-nature reserves in Wenchuan to further protect pandas, and a methodological contribution was made to understand the differences of ESPs between them, thus supporting a methodological formulation of sustainable landscape patterns.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , China , Ecologia
13.
J Environ Manage ; 249: 109315, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442906

RESUMO

The perspective of ecosystem services bundle is virtually a spatial clustering on landscape to mapping the relationship between ecosystem services and support the spatial strategy of landscape management. However, the efficiency of various clustering algorithms for geographically different regions are still in obscurity. In this study, we provided landscape functional zoning as a planning tool based on the ecosystem services bundles formed by carbon sequestration, soil retention and water yield. Then we used four landscape pattern indices to evaluate the performance of six clustering algorithms on landscape functional zoning. The case counties include Lankao, Jinggangshan and Luquan in China. The results showed the Natural Breaks (Jenks) scheme should be the most reasonable zone because of its high aggregated distribution and low diversity. This scheme was adjusted using some other schemes and has been employed as the final 7 kinds of zoning types. There were 5 types appeared in Lankao and Jinggangshan, and 6 types appeared in Luquan. We discussed that landscape functional zone can be a nexus connecting landscape planning and social policy. Rural reconstructing process on landscape was depicted, and landscape functional zone was proposed a practical planning tool bridged human wellbeing. The task of landscape functional zoning with the management indications may provide interdisciplinary support to decision-makers and natural resource users on landscape management.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Algoritmos , China , Planejamento de Cidades , Humanos
14.
Sci Rep ; 9(1): 9707, 2019 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273266

RESUMO

The streamflow of major global rivers changes under the influences of climate change and human activities and varies greatly in different regions. The Yellow River has undergone a dramatic shift during the last six decades. Its streamflow gradually dwindled away and even dried-up severely in the late 20th century, but in recent years it has recovered and remains stable. Comprehensive understanding of the river streamflow change and its driving forces promotes effective water resource management within this complex human-natural system. Here, we develop a runoff identity attribution approach to analyze 61 years of streamflow observations from the Yellow River. We find that between the 1950s and the 1980s, human water consumption contributed more than 90% to streamflow reduction, but from the 1970s onwards, land cover change became the major factor to decrease streamflow. Since 2000, government management schemes have prevented streamflow from declining further and guarantee its stability. Based on the analysis framework we propose, persistent droughts, which are related to abrupt streamflow abatement, may be the most uncontrollable factor in the future. A more resilient management system should be therefore built to grapple with the expected increased frequency of such extreme climate events in the future.

15.
Sci Total Environ ; 660: 765-775, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30743962

RESUMO

Multifunctional landscape has become a new discipline growth point in landscape ecology. Globally mountainous areas occupy about one fifth of Earth's surface. However, few studies focused on landscape multifunctionality in mountainous areas. Taking Dali Bai Autonomous Prefecture, China, as a case study area, five typical landscape functions (net primary productivity, soil retention, water yield, crop production, and residential support) were quantified and mapped. Hotspots of multiple landscape functions were identified using spatial overlap tools, interaction between each landscape function pair was discussed through Spearman's rank correlation analysis, and development zoning was conducted based on landscape function bundle. The results showed that, about 61% of the study area had at least one kind of landscape function hotspot, with only 2.7% covering three or more kinds of landscape function hotspots. Significant trade-offs or synergies existed between all pairs of landscape functions, except the pair of net primary productivity and residential support. With the application of Self-Organizing Feature Maps (SOFM) method, the study area was divided into four types of development zones (i.e. ecological shelter area, ecological transition area, suburban development area, and urban agglomeration area) which were all corresponding to different landscape function bundles. This study could provide spatial guidance for differentiated sustainable developing in mountainous areas according to local conditions of landscape multifunctionality.

16.
J Agric Food Chem ; 67(7): 1927-1936, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30678459

RESUMO

Taurine, a ß-aminosulfonic acid, exerts many cellular physiological functions. It is still unknown whether taurine can regulate milk synthesis in the mammary gland. Therefore, in this study we investigated the effects and mechanism of taurine on milk synthesis in mammary epithelial cells (MECs). Bovine MECs (BMECs) cultured in FBS-free OPTI-MEMImedium were treated with taurine (0, 0.08, 0.16, 0.24, 0.32, and 0.4 mM). Taurine treatment led to increased milk protein and fat synthesis, mTOR phosphorylation, and SREBP-1c protein expression, in a dose-dependent manner, with an apparent maximum at 0.24 mM. Gene function study approaches revealed that the GPR87-PI3K-SETD1A signaling was required for taurine to increase the mTOR and SREBP-1c mRNA levels. Taurine stimulated GPR87 expression and cell membrane localization in a dose dependent manner, suggesting a sensing mechanism of GPR87 to extracellular taurine. Collectively, these data demonstrate that taurine promotes milk synthesis via the GPR87-PI3K-SETD1A signaling.


Assuntos
Histona-Lisina N-Metiltransferase/metabolismo , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Receptores de Ácidos Lisofosfatídicos/metabolismo , Taurina/farmacologia , Animais , Bovinos , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Lipídeos/biossíntese , Proteínas do Leite/biossíntese , RNA Mensageiro/análise , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Homólogo LST8 da Proteína Associada a mTOR/genética
17.
Sci Total Environ ; 651(Pt 1): 979-989, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30257235

RESUMO

Large-scale vegetation restoration has important impacts on plant species diversity, which then influences plant community stability and resilience. The purpose of this paper is to compare the diversity of plantations as well as the diversity of artificially restored and naturally restored grasslands under different years of recovery and to identify the plots with the highest species diversity by vegetation type and restoration duration to determine strategies for vegetation restoration in hilly and gully regions of the Loess Plateau. Stands of Robinia pseudoacacia and Caragana korshinskii of different ages (10, 20, 30 and 40 years old) in the Danangou catchment on the Loess Plateau of China were selected as a case study to analysis effects of afforestation on the structure and function of ecosystems. The results showed that (1) under different numbers of years of recovery, the species diversity of woodland changes with changes in the coverage of woody plants, and the species diversity of R. pseudoacacia plantations planted on sunny slopes and R. pseudoacacia and C. korshinskii plantations planted on shady slopes reaches its maximum when coverage reaches a minimum value after 20 and 30 years of recovery, respectively; (2) soil moisture (in both shallow and deep layers) is the key factor controlling species diversity in woodlands, as the soil moisture changes with the coverage of woody plants following different numbers of years of recovery, which then influences the species diversity; (3) compared to the woodlands, the natural grassland exhibited higher species diversity under all recovery duration. Therefore, natural recovery is recommended if only species diversity is considered rather than human demand for wood, but if demand for materials is considered, we recommend thinning R. pseudoacacia on sunny and shady slopes at the ages of 10-20 and 10-30 years, respectively.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/métodos , Recuperação e Remediação Ambiental/métodos , China , Ecossistema
18.
Environ Manage ; 62(5): 968-986, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30069852

RESUMO

This study proposes a framework for evaluating anthropogenic nitrogen emissions and local vulnerability in order to assess regional ecological risk of human activity during a stable urbanization process. Taiwan, an isolated island with a unique environment, intensive agriculture, concentrated industries, and stable urbanization, was an ideal location for testing this framework. Local vulnerability is influenced by social characteristics, economic development, environmental protection, and other indicators related to these. Within the context of urbanization, therefore, and using official statistical data, human metabolism, agricultural and industrial production, and transportation were evaluated. The results indicate that the rate of anthropogenic nitrogen emissions decreased as the process of urbanization in Taiwan stabilized. While nitrogen emissions from agricultural production, household and industrial wastewater gradually decreased due to a reduction in the area of arable farmland, a reduction in the use of fertilizers and increased sewage treatment, nitrogen emissions from transportation increased due to higher energy consumption from vehicle use. Taiwan exhibited a higher degree of regional vulnerability in 1998 because motor vehicle density increased significantly, while rates of per capita green area and resource recovery remained relatively low. The study found that if Taiwan maintains its current conditions with respect to standard of living, agriculture, industry, and transportation, nitrogen emissions from human metabolism and agricultural and industrial production will not increase regional ecological risk, while nitrogen emissions from transportation will likely increase this risk. Therefore, this paper suggests that future environmental planning in Taiwan should prioritize low-emissions sustainable transportation.


Assuntos
Poluentes Atmosféricos/análise , Conservação dos Recursos Naturais/tendências , Nitrogênio/análise , Urbanização/tendências , Agricultura , Ecologia , Fertilizantes , Humanos , Indústrias , Veículos Automotores , Medição de Risco , Taiwan , Transportes
19.
Sensors (Basel) ; 18(8)2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30096778

RESUMO

With the booming development of the Internet of things (IoT) industry, the demand of positioning technology in various IoT application scenarios is also greatly increased. To meet the positioning requirements of the IoT application, we propose a distance measurement method based on phase regeneration that can provide positioning capability for IoT applications in indoor and outdoor environments. The PRG algorithm consists of two phases: coarse ranging phase and fine ranging phase. Fingerprint positioning algorithm based on Gradient Boost Decision Tree (GBDT) is used to determine coarse distance. The host machine measures the difference between the transmitted carrier phase and the received regenerative carrier phase to fix the fine distance and then the coarse distance is used to determine the carrier phase integer ambiguity. Finally, high precision ranging is realized. Simulation results show that the PRG method can achieve range finding with decimeter level precision under the 10 MHz subcarrier frequency.

20.
Sci Total Environ ; 644: 556-566, 2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-29990905

RESUMO

Land use change can result in variations in ecosystem services (ESs) and their relationships. Studying the temporal dynamics of ESs and their relationships can support scenario analyses that provide the theoretical basis for policy decisions and regional ecosystem management. Previous studies have revealed the trade-offs between two ESs on multiple scales, while the trade-offs between multiple ESs require further analysis. Furthermore, trade-offs are rarely considered in scenario constructions, which weakens the ability of scenarios to inform land use policy. In this study, the InVEST model was applied to assess carbon sequestration, habitat quality, nutrient retention, sediment retention and seasonal water yield at five-year intervals from 1990 to 2015 and to construct five simulated scenarios that represented different ecological restoration and land reclamation policies. The results indicated that the Grain for Green Project (GFGP) increased all ESs, with seasonal water yield increasing by approximately 1.29 times above the initial stage. However, decreasing cropland area reduced the correlations between ESs both in trade-offs and synergies. Among all scenarios studied, the Returning Cropland to Grassland trade-off scenario had the maximum effect, while the natural succession to shrubland scenario had a minimum effect at the pixel level. Except for the land reclamation scenario, the overall ES benefits in the other scenarios exceeded the benefits received in 2015. Given the extent of watershed areas impacted by different overall ES benefit and trade-off situations, the Returning Cropland to Grassland scenario appears to best reduce the impacts of the worst situation compared to 2015, reducing the negative impacts by 22.6%. We suggest that scenarios that combine both overall ESs values and their trade-offs can support more effective and efficient land use decisions.

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