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1.
Glob Chang Biol ; 30(4): e17291, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38647225

RESUMEN

Terrestrial ecosystem resilience is crucial for maintaining the structural and functional stability of ecosystems following disturbances. However, changes in resilience over the past few decades and the risk of future resilience loss under ongoing climate change are unclear. Here, we identified resilience trends using two remotely sensed vegetation indices, analyzed the relative importance of potential driving factors to resilience changes, and finally assessed the risk of future resilience loss based on the output data of eight models from CMIP6. The results revealed that more than 60% of the ecosystems experienced a conversion from an increased trend to a declined trend in resilience. Attribution analysis showed that the most important driving factors of declined resilience varied regionally. The declined trends in resilience were associated with increased precipitation variability in the tropics, decreased vegetation cover in arid region, increased temperature variability in temperate regions, and increased average temperature in cold regions. CMIP6 reveals that terrestrial ecosystems under SPP585 are expected to experience more intense declines in resilience than those under SSP126 and SSP245, particularly in cold regions. These results highlight the risk of continued degradation of ecosystem resilience in the future and the urgency of climate mitigation actions.


Asunto(s)
Cambio Climático , Ecosistema , Temperatura , Modelos Teóricos
2.
BMC Geriatr ; 24(1): 138, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38321378

RESUMEN

BACKGROUND: There is a causal link between childhood socioeconomic status and health status in adulthood and beyond. It's vital to comprehend the relationship between childhood socioeconomic status and mental health among older Chinese individuals from the current generation who have undergone significant social changes in China. This understanding is critical to foster healthy demographic and social development in China. METHODS: Using data from the 2020 China Family Panel Studies, we investigate the relationship between childhood socioeconomic status and depression in older adults. Additionally, we examine the mediating role of adult socioeconomic status and subjective well-being. RESULTS: 1) Childhood socioeconomic status of Chinese older adults differences by region of residence, while depression levels differences by gender, region of residence, and marital status. 2) Adult socioeconomic status mediated the relationship between childhood socioeconomic status and depression in older adults. 3) Adult socioeconomic status and subjective well-being had a chain-mediated role in the relationship between childhood socioeconomic status and depression in older adults. CONCLUSIONS: In terms of childhood socioeconomic status, older adults in urban regions were significantly higher than those in rural regions. As for depression level, female older adults were more depressed than males; married older people have the lowest depression levels, while unmarried and widowed older people have higher depression levels; older adults in rural regions had higher depression levels than those in urban regions. Evidence from our study further suggests that childhood socioeconomic status can suppress the depression level in older adults through adult socioeconomic status; it can also further reduce the depression level in older adults through the chain mediation of adult economic status affecting subjective well-being. As depression is more prevalent among older individuals with a lower childhood socioeconomic status, it is vital to prioritize the extensive impact of childhood socioeconomic status as a distal factor and investigate "upstream" solutions to enhance childhood socioeconomic status and reduce the gap during the early years of life.


Asunto(s)
Depresión , Clase Social , Masculino , Humanos , Femenino , Anciano , Depresión/psicología , Factores Socioeconómicos , Estado de Salud , Salud Mental , China
3.
J Environ Manage ; 356: 120617, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38537466

RESUMEN

Residents' environmental attitudes (EAs) towards ecological restoration programs are vital for evaluating program effectiveness and promoting environmental management. However, most local studies have neglected the indirect environmental contextual influences on residents' EAs, and have omitted the regional variations in the environmental contextual influences. To investigate the multilevel factors affecting residents' EAs, we conducted a transect survey that included the eastern, middle, and western regions in northern China's drylands, where have experienced ecological restoration. Multilevel linear models (MLMs) were applied to analyse the direct and indirect impacts of environmental contexts and individual characteristics on rural residents' EAs. The results showed the environmental context can indirectly impact EAs by amplifying the influence of individual characteristics such as family structure and income on EAs. The EAs are influenced by different local environmental contexts among the east, middle and west of China's drylands. The humidity attitude was influenced by precipitation only in the highly arid western and middle regions, while precipitation attitude is strongly influenced by land surface temperature and humidity in eastern China's drylands. These findings hold important implications for understanding the cross-scale impact of environmental contexts on EAs in drylands.


Asunto(s)
Actitud , Renta , Humanos , Población Rural , China
4.
Glob Chang Biol ; 29(13): 3562-3574, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36708329

RESUMEN

Recovery time, the time it takes for ecosystems to return to normal states after experiencing droughts, is critical for assessing the response of ecosystems to droughts; however, the spatial dominant factors determining recovery time are poorly understood. We identify the global patterns of terrestrial ecosystem recovery time based on remote sensed vegetation indices, analyse the affecting factors of recovery time using random forest regression model, and determine the spatial distribution of the dominant factors of recovery time based on partial correlation. The results show that the global average recovery time is approximately 3.3 months, and that the longest recovery time occurs in mid-latitude drylands. Analysis of affecting factors of recovery time suggests that the most important environmental factor affecting recovery time is soil moisture during the recovery period, followed by temperature and vapour pressure deficit (VPD). Recovery time shortens with increasing soil moisture and prolongs with increasing VPD; however, the response of recovery time to temperature is nonmonotonic, with colder or hotter temperatures leading to longer recovery time. Soil moisture dominates the drought recovery time over 58.4% of the assessed land area, mostly in the mid-latitudes. The concern is that soil moisture is projected to decline in more than 65% regions in the future, which will lengthen the drought recovery time and exacerbate drought impacts on terrestrial ecosystems, especially in southwestern United States, the Mediterranean region and southern Africa. Our research provides methodological insights for quantifying recovery time and spatially identifies dominant factors of recovery time, improving our understanding of ecosystem response to drought.


Asunto(s)
Sequías , Ecosistema , Suelo , Temperatura , Sudoeste de Estados Unidos , Cambio Climático
5.
Glob Chang Biol ; 29(3): 702-718, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36270805

RESUMEN

The ecosystems of the Tibetan Plateau (TP) provide multiple important ecosystem services that benefit both local populations and those beyond, such as through climate regulation services on precipitation for East Asia and China. However, the precipitation regulation service of the TP ecosystems for supplying moisture and maintaining precipitation is yet to be evaluated. In this study, we used the moisture recycling framework and a moisture tracking model to quantify the precipitation regulation services of TP ecosystems for their contribution to precipitation. We found TP ecosystems contributed substantially to local and downwind precipitation, with a contribution of 221 mm/year for the TP and neighboring areas through evapotranspiration (ET) (104 mm/year through transpiration), declined to <10 mm/year for eastern China and other surrounding countries. Among ecosystem types, grassland contributed most to precipitation, followed by barren and snow lands, forests, and shrublands. In terms of seasonality, precipitation contribution from TP ecosystems was greater in summer months than in non-summer months for western China, while the opposite was true for eastern China-although the magnitude was much smaller. Over the past two decades, the significant ET increases in TP translated to a widespread increase in precipitation contribution for TP and downwind beneficiary regions from 2000 to 2020. Our study provides a quantitative way to understand the precipitation regulation services of TP ecosystems through moisture recycling, substantiating their key role to maintain precipitation and the water cycle for downwind regions-effectively acting as an ecological safeguard that could be perceived by the public.


Asunto(s)
Clima , Ecosistema , Tibet , Estaciones del Año , Bosques
6.
Rev Cardiovasc Med ; 24(9): 257, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39076379

RESUMEN

Background: Although compliance with the guideline recommendations for heart failure (HF) is associated with improved survival, the effects of medication on clinical practice often fail to meet expectations due to physician and/or patient-related reasons that are unclear. This study analyzed physicians' compliance with guideline-directed medical therapy (GDMT) based on real-world clinical data and identified risk factors of low compliance. Methods: This study included patients with HF, who were treated at the Affiliated Hospital of North Sichuan Medical College from July 2017 to June 2021. All patients were divided into high compliance, moderate compliance, and low compliance with GDMT groups. The proportion of patients receiving treatment in compliance with GDMT was analyzed, the relationship between compliance with GDMT and clinical outcomes was evaluated, and the risk factors of low compliance were identified. Results: Of all patients with HF included in the study, 498 (23.8%) had low compliance with GDMT, 1413 (67.4%) had moderate compliance with GDMT, and 185 (8.8%) had high compliance with GDMT. The readmission rate of patients in the moderate compliance with GDMT group was significantly higher than that in the high and low compliance groups (p = 0.028). There were no significant differences in the rates of severe cardiovascular disease among the three groups. The mortality rate of patients in the high compliance with GDMT group was significantly higher than that of the other groups (p < 0.001). We found that a history of hypertension; New York Heart Association (NYHA) classification (III and IV vs. I); and abnormal heart rate, high-sensitive troponin T (hsTnT), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), uric acid, and left ventricular diastolic dysfunction (LVDD) were all significantly associated with low compliance with GDMT. Conclusions: The proportion of physicians' compliance with GDMT in treating patients with HF is low. Risk factors of low compliance include hypertension; NYHA classification (III and IV vs. I); and abnormal heart rate, hsTnT, NT proBNP, uric acid, and LVDD.

7.
Nanotechnology ; 34(12)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36548986

RESUMEN

Recently, carbon dots (CDs) have exhibited promising applications in the fluorescence detection of various ions and biomolecules. In this work, one kind of nitrogen-doped CDs (N-CDs) with high fluorescence intensity was synthesized, characterized by transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier-transform infrared, UV-vis absorption spectra, and fluorescence spectra. The results show that the spherical and uniform N-CDs (quantum yield: 60.2%) have remarkable fluorescence properties and photostability, which makes N-CDs can be utilized as an 'on-off-on' sensor for Hg2+and glutathione (GSH). In addition, the pH-sensitive behavior of N-CDs makes it also applicable to H+detection under acid conditions (pKa = 3.53). The linear range of the 'turn-off' sensor detecting Hg2+was 0.014-50µM, with a 0.014µM limit of detection (LOD). GSH was detected by the fluorescence 'turn-on' method with a linear range of 0.125-60µM and a LOD of 0.125µM. The outstanding performance of N-CDs makes it potential applications in ecological pollution and biomolecule visualization monitoring.


Asunto(s)
Mercurio , Puntos Cuánticos , Colorantes Fluorescentes/química , Carbono/química , Puntos Cuánticos/química , Espectrometría de Fluorescencia/métodos , Glutatión , Iones , Nitrógeno/química , Concentración de Iones de Hidrógeno
8.
J Fluoresc ; 33(2): 459-469, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36441340

RESUMEN

Carbon dots (CDs) have excellent fluorescence properties and can be used in many research fields. In this paper, carbon dots were prepared by microwave-assisted pyrolysis of citric acid and urea, characterized by transmission electron microscope (TEM), X-ray diffractometer (XRD), 13C-NMR spectrum, zeta potential, Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-vis) absorption and fluorescence spectra, and detected the Hg2+ and ascorbic acid (AA) sequentially. It showed that carbon dots were hollow, spherical particles and less than 10 nm, photoluminescence quantum yield of carbon dots was about 15%. The CDs were selective and sensitive to Hg2+ and AA based on the "on-off-on" fluorescence behavior. The detection limits of CDs for Hg2+ and AA were 0.138 µM and 0.212 µM, respectively. Fluorescence response mechanism of CDs was also discussed.


Asunto(s)
Mercurio , Puntos Cuánticos , Ácido Ascórbico , Puntos Cuánticos/química , Carbono/química , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría de Fluorescencia , Colorantes Fluorescentes/química
9.
Int J Biometeorol ; 67(11): 1789-1802, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37561207

RESUMEN

COVID-19 has ravaged Brazil, and its spread showed spatial heterogeneity. Changes in the environment have been implicated as potential factors involved in COVID-19 transmission. However, considerable research efforts have not elucidated the risk of environmental factors on COVID-19 transmission from the perspective of infectious disease dynamics. The aim of this study is to model the influence of the environment on COVID-19 transmission and to analyze how the socio-ecological factors affecting the probability of virus transmission in 10 states dramatically shifted during the early stages of the epidemic in Brazil. First, this study used a Pearson correlation to analyze the interconnection between COVID-19 morbidity and socio-ecological factors and identified factors with significant correlations as the dominant factors affecting COVID-19 transmission. Then, the time-lag effect of dominant factors on the morbidity of COVID-19 was investigated by constructing a distributed lag nonlinear model and standard two-stage meta-analytic model, and the results were considered in the improved SEIR model. Lastly, a machine learning method was introduced to explore the nonlinear relationship between the environmental propagation probability and socio-ecological factors. By analyzing the impact of environmental factors on virus transmission, it can be found that population mobility directly caused by human activities had a greater impact on virus transmission than temperature and humidity. The heterogeneity of meteorological factors can be accounted for by the diverse climate patterns in Brazil. The improved SEIR model was adopted to explore the interconnection of COVID-19 transmission and the environment, which revealed a new strategy to probe the causal links between them.

10.
J Environ Manage ; 326(Pt B): 116756, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36423408

RESUMEN

Drought is a major driver of interannual variability in the gross primary productivity (GPP) of global terrestrial ecosystems, and drought recovery time has been widely used to assess ecosystem responses to drought. However, the response of the carbon-water coupled cycle to drought, especially changes in the correlation between drought intensity and carbon-water coupling throughout the recovery time, remains unclear. In this study, the Yellow River Basin (YRB) located mostly in drylands was the study area. We assessed the correlation between the standardized water vapour pressure deficit (VPD) and the water use efficiency of ecosystems (WUEe) and water use efficiency of canopies (WUEc) every month with the drought recovery time of GPP. We found that the drought intensity in the middle reach of the YRB (MYRB) was greater and the drought recovery time was longer than those in the upper reach (UYRB) and lower reach (LYRB) during the period from 2003 to 2017. In terms of the correlation between drought intensity and carbon-water coupling, the greater the VPD was, the lower the WUEc. In addition, the correlation of WUEc with VPD was higher than that of WUEe in most areas of the YRB, especially in the LYRB. On the watershed level, the correlation between the two types of WUE and VPD increased gradually with the recovery time, while the correlation between WUEc and VPD (mostly negative) changed more than the correlation between WUEe and VPD (mostly positive). Therefore, the response of WUEc to meteorological drought should be given more attention, especially during the middle and late stages of drought, since it exhibited an opposite signal compared to that of WUEe during drought recovery.


Asunto(s)
Sequías , Ecosistema , Presión de Vapor , Ríos , Carbono
11.
J Environ Manage ; 335: 117514, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36841000

RESUMEN

Ecological restoration is an important approach to improving landscape sustainability. However, ecological restoration in drylands is strongly limited by water resources. Therefore, a technical route for ecological restoration in drylands that creates sustainable landscapes based on those water constraints is needed. In this study, we develop a spatially explicit framework named "Constraint-Pattern-Benefit" to plan ecological restoration patterns in Inner Mongolia, China. Based on a prediction of the ecosystem service (ES) increase under limited evapotranspiration as a water constraint, we constructed 5 landscape sustainability-related strategies with 100 ecological restoration scenarios, which considered fragmentation of restoration locations, distance to city, water consumption, and the allocation scale to determine the spatial arrangement of ecological restoration. Results show that the ES increase potential of ecological restoration under water constraints is distributed in the center of Inner Mongolia. The multi-objective scenario simultaneously achieves 59.1% water yield, 74.2% soil conservation, 57.2% sand fixation, and 52.8% carbon sequestration with 50% restored landscape. Considering the indicators of fragmentation, water consumption, and distance to city decreases the restored landscape fragmentation from 0.44 to 0.26, improves the restoration efficiency by 14.41%, and increases the beneficiary population by 35.5%, respectively. Small-scale allocation can further increase the ES realization efficiency, which is on average 4.8% higher at the city scale than at the provincial scale. Moreover, this approach focuses on the sustainable effect of the spatial arrangement on dryland landscapes at different scales, which provides methodological support for improving the sustainability of drylands.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Agua , China , Suelo
12.
J Environ Manage ; 326(Pt A): 116644, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36370611

RESUMEN

Humans and water are closely connected in large river basins and form social-ecological systems (SESs). However, cross-scale effect in SESs make it difficult to identify the key forces driving human-water connections at the community scale when ignoring the landscape context. Focusing on the incongruous human-water relationships in the lower reaches of the Yellow River, we built local resident perception-based networks linking the agricultural subsystem, environmental subsystem, and cultural subsystem by distributing farmer household questionnaires and extracted 13 indicators from 7 kinds of network metrics to indicate human-water connections. We applied analysis of variance (ANOVA), random forest (RF) and multilevel linear model (MLM) methods to identify the driving forces of perception-based human-water connections among 20 factors at both the community and landscape scales. The results showed that the perception-based network indicators were mainly directly influenced by community-level driving factors, especially the accessibility of information, such as the frequency of going out, the frequency of accessing the Yellow River channel, and the information source for the national policy on the Yellow River. The influences of community-level driving factors on network indicators were affected by landscape-level driving factors, e.g., the nighttime light, population density, gross domestic product and proportion of artificial land, thus indicating indirect influences from the landscape context. These analyses and findings can enrich the methods by which social, ecological and hydrological elements are structurally linked in sociohydrologic research and highlight the cross-scale effect of the landscape context on human-water systems at the community level.


Asunto(s)
Ríos , Agua , Humanos , Monitoreo del Ambiente/métodos , Ecosistema , Percepción , China
13.
Entropy (Basel) ; 24(10)2022 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-37420479

RESUMEN

To address the difficulty of extracting the features of composite-fault signals under a low signal-to-noise ratio and complex noise conditions, a feature-extraction method based on phase-space reconstruction and maximum correlation Re'nyi entropy deconvolution is proposed. Using the Re'nyi entropy as the performance index, which allows for a favorable trade-off between sporadic noise stability and fault sensitivity, the noise-suppression and decomposition characteristics of singular-value decomposition are fully utilized and integrated into the feature extraction of composite-fault signals by the maximum correlation Re'nyi entropy deconvolution. Verification based on simulation, experimental data, and a bench test proves that the proposed method is superior to the existing methods regarding the extraction of composite-fault signal features.

14.
Sensors (Basel) ; 21(23)2021 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-34883873

RESUMEN

The traditional signal of opportunity (SOP) positioning system is equipped with dedicated receivers for each type of signal to ensure continuous signal perception. However, it causes a low equipment resources utilization and energy waste. With increasing SOP types, problems become more serious. This paper proposes a new signal perception unit for SOP positioning systems. By extracting the perception function from the positioning system and operating independently, the system can flexibly schedule resources and reduce waste based on the perception results. Through time-frequency joint representation, time-frequency image can be obtained which provides more information for signal recognition, and is difficult for traditional single time/frequency-domain analysis. We also designed a convolutional neural network (CNN) for signal recognition and a negative learning method to correct the overfitting to noisy data. Finally, a prototype system was built using USRP and LabVIEW for a 2.4 GHz frequency band test. The results show that the system can effectively identify Wi-Fi, Bluetooth, and ZigBee signals at the same time, and verified the effectiveness of the proposed signal perception architecture. It can be further promoted to realize SOP perception in almost full frequency domain, and improve the integration and resource utilization efficiency of the SOP positioning system.


Asunto(s)
Redes Neurales de la Computación , Ruido , Percepción
15.
J Environ Manage ; 291: 112689, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33962289

RESUMEN

Dryland ecosystems are experiencing dramatic climate change, either drier or wetter. However, the differences in response amplitudes of dryland ecosystems to drier and wetter climates have not been frequently discussed, especially when using composite indicators at large scales. This study explores the changing patterns of ecosystem vulnerability in China's drylands by comprehensively considering exposure, sensitivity and resilience indicators using leaf area index (LAI) datasets and meteorological data within two periods from 1982 to 1999 (P1) and from 2000 to 2016 (P2). The results show that nearly 57% of China's drylands have experienced drier conditions in 2000-2016 based on the average aridity index (AI) values compared with the conditions in 1982-1999. Compared with the conditions in 1982-1999, ecosystem vulnerability has increased in 78% of dryland, and ecosystem resilience has decreased in 46% of the area in 2000-2016. The amplitudes of vulnerability increase are higher in drier conditions than in wetter conditions. Ecosystem resilience has obviously increased in wetter conditions but has decreased in drier conditions, especially in farming-pastoral ecotones with an obvious land use change. Consequently, vegetation-climate composite indicators provide a holistic pattern of China's dryland ecosystem response to climate change, and the decreased ecosystem resilience in drier conditions in northeast China should be a warning signal under the national vegetation greening background. This research highlights that the impact of drying on ecosystem resilience leads the response of ecosystems to drier environment.


Asunto(s)
Cambio Climático , Ecosistema , Agricultura , China
16.
J Environ Manage ; 292: 112783, 2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-34015616

RESUMEN

Monitoring landscape pattern change can provide spatial explicit basis for future landscape management. The future socioeconomic and climate change drivers should be systematically combined in landscape pattern monitoring, while they are often regarded as independent parameters in landscape monitoring models. This study sought to project the detailed landscape pattern change based on landscape composition and configuration in Tibet by 2030, and combined the shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs). The results showed area of the unused land and forest will reduce by a minimum standard of 11.42 × 104 and 9.04 × 104 km2 from 2010 to 2030, respectively. Other land use types will increase, and the highest increase in grassland will be 9.30 × 105 km2. Combined SSP1 and RCP2.6 scenario show high landscape aggregation and low edge density on cultivated land, urban land and grassland in Tibet as a whole. However, in typical cultivated and urban landscape, the abovementioned rule is appeared in the combined SSP4 and RCP6.0 scenario. These findings stress the importance of systematically modeling the socioeconomic demand and climate change in landscape pattern monitoring, and using both landscape composition and configuration indexes for scenario evaluation.


Asunto(s)
Cambio Climático , Bosques , Tibet
17.
J Environ Manage ; 251: 109615, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31581043

RESUMEN

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.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , China , Ecología , Humanos , Población Rural
18.
J Environ Manage ; 249: 109315, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31442906

RESUMEN

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.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Algoritmos , China , Planificación de Ciudades , Humanos
19.
Sensors (Basel) ; 18(8)2018 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-30096778

RESUMEN

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.
Environ Manage ; 62(5): 968-986, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30069852

RESUMEN

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.


Asunto(s)
Contaminantes Atmosféricos/análisis , Conservación de los Recursos Naturales/tendencias , Nitrógeno/análisis , Urbanización/tendencias , Agricultura , Ecología , Fertilizantes , Humanos , Industrias , Vehículos a Motor , Medición de Riesgo , Taiwán , Transportes
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