84 research outputs found
Geomorphometric characterisation of natural and anthropogenic land covers
Abstract The scientific community has widely discussed the role of abiotic and biotic forces in reshaping the Earth's surface. Currently, the literature is debating whether humans are leaving a topographic signature on the landscape. Apart from the influence of humans on processes, does the resulting landscape bear an unmistakable signature of anthropogenic activities? This research analyses from a statistical point of view the morphological signature of anthropogenic and natural land covers in different topographic context, as a fundamental challenge in the emerging debate of human-environment relationships and the modelling of global environmental change. It aims to explore how intrinsically small-scale processes, related to land use, can influence the form of entire landscapes and to determine whether these processes create a distinctive topography. The work focusses on four study areas in floodplains, plain to hilly, hills and mountains, for which LiDAR-derived Digital Terrain Models (DTMs) are available. Surface morphology is described with different geomorphometric parameters (slope, mean curvature and surface peak curvature) and their frequency distribution. The results show that the distribution of geomorphometric indices can reveal anthropogenic land covers and landscapes. In most cases, different land covers show statistically significant differences (p < 0.05) in their morphology. Finally, this study demonstrates the possibility to use a geomorphic analysis to quantify anthropogenic impact based on land covers in different landscape contexts. This provides useful insight into understanding the impact of human activities on the present morphology and offers a comprehensive understanding of coupling human-land interaction from a geomorphological point of view
From a Spatial Structure Perspective : Spatial-Temporal Variation of Climate Redistribution of China Based on the Köppen–Geiger Classification
https://doi.org/10.1029/2022GL099319Shifting climate zones are widely used to diagnose and predict regional climate change. However, few attempts have been made to measure the spatial redistribution of these climate zones from a spatial structure perspective. We investigated changes in spatial structure of Köppen climate landscape in China between 1963 and 2098 with a landscape aggregation index. Our results reveal an apparent signal from fragmentation to aggregation, accompanied by the intensification of areal dispersion between cold and warm climate types. Our attribution analysis indicates that anthropogenic forcings have a larger influence on changes of spatial structure than natural variation. We also found that topographical heterogeneity is likely to contribute to the regional spatial fragmentation, especially in the Qinghai-Tibet Plateau. However, we also found that the spatial fragmentation will be weakened around the mid-2040s. We argue that biodiversity is likely to be mediated by spatial structure of future climate landscapes in China.Peer reviewe
Xinfeng capsule improves pulmonary function in ankylosing spondylitis patients via NF-ÎşB-iNOS-NO signaling pathway
AbstractObjectiveTo study changes in the nuclear factor-κB p65 (NF-κB p65)-inducible nitric oxide synthase (iNOS)-nitric oxide (NO) signaling pathway and the effects of Xinfeng capsules (XFC) in patients with ankylosing spondylitis (AS)MethodsOne hundred twenty patients with AS were randomly divided into an XFC group and a Salazopyrin group. Sixty health subjects were included as a normal control group. In the two treatment groups, pulmonary functional parameters, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), maximal voluntary ventilation (MVV), peak expiratory flow (PEF), forced expiratory flow at 25% of forced vital capacity (FEF25), forced expiratory flow at 50% of forced vital capacity (FEF50), and forced expiratory flow at 75% of forced vital capacity (FEF75) were determined. Enzyme linked immunosorbent assays were used for detection of the serum oxidative stress indexes, NF-κB p65, iNOS, NO, reactive oxygen species (ROS), reactive nitrogen species (RNS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidative capacity (TAOC) and interleukin-4 (IL-4), IL-10, IL-1β, and tumor necrosis factor-α (TNF-α) contents. Westergren's method was used for determination of erythrocyte sedimentation rate (ESR). High-sensitivity C-reactive protein (Hs-CRP) was detected with a 7060 full-automatic biochemical analyzer (Hitachi, Japan).ResultsThe clinical therapeutic effect in the XFC group was significantly superior to that in the Salazopyrin group (P<0.01). Compared with the normal control group, FEV1, MVV, PEF, FEF50, FEF75, SOD, CAT, TAOC, IL-4, IL-10 were significantly lower, and NF-κB p65, iNOS, NO, ROS, RNS, MDA, IL-1β, TNF-α, ESR, and Hs-CRP significantly higher in patients with AS (P<0.01 or P<0.05). Compared with before treatment, FEV1, MVV, PEF, FEF50, FEF75, SOD, CAT, TAOC, IL-4, and IL-10 were significantly increased, and NF-κB p65, iNOS, NO, ROS, RNS, MDA, IL-1β, TNF-α, ESR, CRP, visual analog scales (VAS), Bath ankylosing spondylitis disease active index, Bath ankylosing spondylitis functional index, and Bath ankylosing spondylitis global index significantly decreased in the two treatment groups after treatment (P< 0.01 or P<0.05), with significant differences between the XFC and Salazopyrin groups (P<0.01 or P<0.05). Spearman correlation analysis indicated that FEV1, MVV, PEF, FEF50, and FEF75 were positively correlated with SOD, CAT, TAOC, IL-4, and IL-10, and were negatively correlated with NF-κB p65, iNOS, NO, ROS, RNS, MDA, IL-1β, TNF-α, ESR, and CRP.ConclusionPatients with AS have local pathologic changes in the spinal cord and other joints. They also have decreased pulmonary function, which is negatively correlated with the NF-κB-iNOS-NO signaling pathway, oxidative indexes, and inflammatory factors. XFC improves rigidity and pain in spinal joints and other symptoms, laboratory indexes, and pulmonary function. The mechanism is possibly related to inhibition of the NF-κB-iNOS-NO signaling pathway
Metformin Uniquely Prevents Thrombosis by Inhibiting Platelet Activation and mtDNA Release
Thrombosis and its complications are the leading cause of death in patients with diabetes. Metformin, a first-line therapy for type 2 diabetes, is the only drug demonstrated to reduce cardiovascular complications in diabetic patients. However, whether metformin can effectively prevent thrombosis and its potential mechanism of action is unknown. Here we show, metformin prevents both venous and arterial thrombosis with no significant prolonged bleeding time by inhibiting platelet activation and extracellular mitochondrial DNA (mtDNA) release. Specifically, metformin inhibits mitochondrial complex I and thereby protects mitochondrial function, reduces activated platelet-induced mitochondrial hyperpolarization, reactive oxygen species overload and associated membrane damage. In mitochondrial function assays designed to detect amounts of extracellular mtDNA, we found that metformin prevents mtDNA release. This study also demonstrated that mtDNA induces platelet activation through a DC-SIGN dependent pathway. Metformin exemplifies a promising new class of antiplatelet agents that are highly effective at inhibiting platelet activation by decreasing the release of free mtDNA, which induces platelet activation in a DC-SIGN-dependent manner. This study has established a novel therapeutic strategy and molecular target for thrombotic diseases, especially for thrombotic complications of diabetes mellitus
Nutrient regulation of biological nitrogen fixation across the tropical western North Pacific
Nitrogen fixation is critical for the biological productivity of the ocean, but clear mechanistic controls on this process remain elusive. Here, we investigate the abundance, activity, and drivers of nitrogen-fixing diazotrophs across the tropical western North Pacific. We find a basin-scale coherence of diazotroph abundances and N 2 fixation rates with the supply ratio of iron:nitrogen to the upper ocean. Across a threshold of increasing supply ratios, the abundance of nifH genes and N 2 fixation rates increased, phosphate concentrations decreased, and bioassay experiments demonstrated evidence for N 2 fixation switching from iron to phosphate limitation. In the northern South China Sea, supply ratios were hypothesized to fall around this critical threshold and bioassay experiments suggested colimitation by both iron and phosphate. Our results provide evidence for iron:nitrogen supply ratios being the most important factor in regulating the distribution of N 2 fixation across the tropical ocean
A longitudinal resource for population neuroscience of school-age children and adolescents in China
During the past decade, cognitive neuroscience has been calling for population diversity to address the challenge of validity and generalizability, ushering in a new era of population neuroscience. The developing Chinese Color Nest Project (devCCNP, 2013–2022), the first ten-year stage of the lifespan CCNP (2013–2032), is a two-stages project focusing on brain-mind development. The project aims to create and share a large-scale, longitudinal and multimodal dataset of typically developing children and adolescents (ages 6.0–17.9 at enrolment) in the Chinese population. The devCCNP houses not only phenotypes measured by demographic, biophysical, psychological and behavioural, cognitive, affective, and ocular-tracking assessments but also neurotypes measured with magnetic resonance imaging (MRI) of brain morphometry, resting-state function, naturalistic viewing function and diffusion structure. This Data Descriptor introduces the first data release of devCCNP including a total of 864 visits from 479 participants. Herein, we provided details of the experimental design, sampling strategies, and technical validation of the devCCNP resource. We demonstrate and discuss the potential of a multicohort longitudinal design to depict normative brain growth curves from the perspective of developmental population neuroscience. The devCCNP resource is shared as part of the “Chinese Data-sharing Warehouse for In-vivo Imaging Brain” in the Chinese Color Nest Project (CCNP) – Lifespan Brain-Mind Development Data Community (https://ccnp.scidb.cn) at the Science Data Bank
The quantification of the socio-economic impact on geomorphology
It is acknowledged that the Earth’s surface was shaped by natural processes such as tectonic uplift, erosion and sediment movement. Nevertheless, recently, the human society as a new force to reshape the landscape has been perceived by the scientific community. The Anthropocene working group (AWG), which is a part of subcommission on Quaternary Stratigraphy – International commission on Stratigraphy of International Union of Geological Science (IUGS) proposed to mark the current geologic time unit as Anthropocene. The AWG declared human beings stepped into an epoch that our societies have become a global geophysical force and the extent of human intervention on geomorphic processes has become comparable to nature, and the trend is accelerating.
Humans act as a geomorphic agent shaping Earth’s surface through activities ranging from agricultural tillage, mining, road networks and building constructions. These activities leave significant signatures on the topography, literally and figuratively across millennia and reflecting the socio-economic conditions of the societies that produce them. People tend to live in the surroundings where resources such as food and fuel are cheaper and more accessible, and the economic and social demands of resources drive the land-use changes to meet the demands. As the human population has grown and the power of technology has expanded, the socio-economic demands have scaled up, the landscapes were imprinted by the rapid increase of anthropogenic modification caused by deforestation, agricultural expansion and urban construction to supply the food and energy demands. The Great Acceleration witnessed remarkable explosion of socio-economic development, with significant consequences on the surface topography. It is estimated that humans have shaped around one-third of the landscape through agricultural fields, pastures, or urban landscapes.
However, an empirical computation to link between socio-economic development, land-use changes and the geomorphology alterations is still a gap. Societal-based understanding of anthropogenic geomorphology provides the way of how human activities involved in natural environmental changes such as soil erosion, floods and tectonic uplifts with the timeline. We synthesized scientific evidence on the emergence, history of present anthropogenic features and illustrated how these features impact the Earth's surface processes. Then we integrated social-geophysical approaches to interpreting a full range of anthropogenic features with identification of remote sensing techniques and reconstruction of the long-term changes by archaeologists, as diagnostic fingerprints of the social processes that formed them. Further, we testified that the natural landscape and anthropogenic landscape present a significant difference in geomorphic signatures, and implied that anthropogenic force shapes the geomorphology in a way different from natural force. Lastly, we used the nighttime light data to represent the socioeconomic status and SLLAC (Slope Local Length of Autocorrelation) metrics to measure the anthropogenic modification on the landscape, and then to assess the correlation between socio-economic impact on the geomorphology based on each stratification of a global pattern.
This thesis helps to understand how the features that human left on the topography affect the Earth surface processes, interpret those features as sociocultural fingerprints, demonstrate that the anthropogenic forcing leaves a different topographic signature on the surface from the natural forcing, and quantify the correlation between socio-economic development and anthropogenic geomorphology. This research not only fill the gap in why people shape the landscape through a diversity of activities; it also presents a possible correlation between socio-economic development and anthropogenic geomorphology. This work also provides the possibility towards an empirical estimation of landscape under the human’s impact at a global scale, and underlines that an integrated approach combining social economy, ecology and geomorphology is needed for the future landscape management
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