11 research outputs found
Trajectory Tracking Control Design for UAV Based on MPC and Active Disturbance Rejection
No full text
Grey Tienshan Urumqi Glacier No.1 and light-absorbing impurities
No full textThe Tienshan Urumqi Glacier No.1 (TUG1) usually shows "grey" surfaces in summers. Besides known regional warming, what should be responsible for largely reducing its surface albedo and making it look "grey"? A field campaign was conducted on the TUG1 on a selected cloud-free day of 2013 after a snow fall at night. Fresh and aged snow samples were collected in the field, and snow densities, grain sizes, and spectral reflectances were measured. Light-absorbing impurities (LAIs) including black carbon (BC) and dust, and number concentrations and sizes of the insoluble particles (IPs) in the samples were measured in the laboratory. High temperatures in summer probably enhanced the snow ageing. During the snow ageing process, the snow density varied from 243 to 458 kg m(-3), associated with the snow grain size varying from 290 to 2500 mu m. The concentrations of LAIs in aged snow were significantly higher than those in fresh snow. Dust and BC varied from 16 ppm and 25 ppb in fresh snow to 1507 ppm and 1738 ppb in aged snow, respectively. Large albedo difference between the fresh and aged snow suggests a consequent forcing of 180 W m(-2). Simulations under scenarios show that snow ageing, BC, and dust were responsible for 44, 25, and 7 % of the albedo reduction in the accumulation zone, respectively.Chinese Academy of Sciences [KJZD-EW-G03-03]; Visiting Scholarship Program of the China Scholarship Council; China Special Fund for Meteorological Research in the Public Interest [GYHY201406016]; Special Fund on Climate Change of China Meteorological AdministrationSCI(E)[email protected]
A Fault-Tolerant Location Approach for Transient Voltage Disturbance Source Based on Information Fusion
No full textThis paper proposed a fault-tolerant approach based on information fusion (IF) to automatically locate the transient voltage disturbance source (TVDS) in smart distribution grids. We first defined three credibility factors that will influence the reliability of the direction-judgments at each power quality monitor (PQM). Then we proposed two rules of influence and a verification factor for the distributed generation (DG) integration. Based on the two sets of direction-judgment criteria, a novel decision-making method with fault tolerance based on the IF theory is proposed for automatic location of the TVDS. Three critical schemes, including credibility fusion, conflict weakening, and correction for DG integration, have been integrated in the proposed fusion method, followed by a reliability evaluation of the location results. The proposed approach was validated on the IEEE 13-node test feeder, and the TVDS location results demonstrated the effectiveness and fault tolerance of the IF based approach
Fault-tolerant location of transient voltage disturbance source for DG integrated smart grid
No full textIn this paper, a new fault-tolerant approach based on improved particle swarm optimization (IPSO) is proposed to automatically locate the transient voltage disturbance source (TVDS) for smart grid with distributed generation (DG) integration. We first analyze the influence of the DG integration on the TVDS direction-judgments. Two new credibility indexes, the monitoring-credibility and the partial-credibility, are defined to measure the reliability of direction-judgment result at each power quality monitor (PQM) with consideration of multiple factors, including DG integration, disturbance intensity and fluctuation characteristic. By using these credibility indexes and a newly defined search space, a heuristic searching approach, called IPSO, is then proposed to obtain the optimal solution of the TVDS location. Simulation study is carried out on the IEEE 34 node test feeder, and the results demonstrate that the proposed approach has significantly improved fault-tolerant capability with satisfatory convergence speed
Additional file 1 of Lymphocyte activating gene 3 protein expression in nasopharyngeal carcinoma is correlated with programmed cell death-1 and programmed cell death ligand-1, tumor-infiltrating lymphocytes
No full textAdditional file 1: Figure S1. Hematoxylin–eosin (HE) staining of all 15 NPC cell lines (× 20). Scale bars: 50 μm
Regulation of photosensation by hydrogen peroxide and antioxidants in C. elegans.
No full textThe eyeless C. elegans exhibits robust phototaxis behavior in response to short-wavelength light, particularly UV light. C. elegans senses light through LITE-1, a unique photoreceptor protein that belongs to the invertebrate taste receptor family. However, it remains unclear how LITE-1 is regulated. Here, we performed a forward genetic screen for genes that when mutated suppress LITE-1 function. One group of lite-1 suppressors are the genes required for producing the two primary antioxidants thioredoxin and glutathione, suggesting that oxidization of LITE-1 inhibits its function. Indeed, the oxidant hydrogen peroxide (H2O2) suppresses phototaxis behavior and inhibits the photoresponse in photoreceptor neurons, whereas other sensory behaviors are relatively less vulnerable to H2O2. Conversely, antioxidants can rescue the phenotype of lite-1 suppressor mutants and promote the photoresponse. As UV light illumination generates H2O2, we propose that upon light activation of LITE-1, light-produced H2O2 then deactivates LITE-1 to terminate the photoresponse, while antioxidants may promote LITE-1's recovery from its inactive state. Our studies provide a potential mechanism by which H2O2 and antioxidants act synergistically to regulate photosensation in C. elegans
Current status and recent changes of glaciers in Tajikistan
No full textTajikistan contains the majority of Central Asia’s glaciers, which cover about 6.00% of the national territory; their rapid shrinkage poses a significant threat to regional water resource security. However, glacier monitoring in Tajikistan was interrupted after 1991, creating a substantial gap in understanding the current state and temporal evolution of these glaciers. Based on glacier inventory data, in situ measurements, and published literature, this study examined the present status and recent variations of glaciers in Tajikistan through data integration and validation, literature collation and comparative analysis, and the application of Geographic Information System (GIS) spatial analysis techniques. As of 2023, Tajikistan possesses a total of 11,528 glaciers, encompassing an area of 7624.48 (±305.58) km2. Small glaciers dominate in number, whereas large glaciers account for the majority of the total area. Over the past two decades, the glacier count has decreased by 2014, and the total area has decreased by 628.98 km2, corresponding to an average annual reduction rate of 0.33%. Regional shrinkage rates range from 4.10% to 22.28%. Glaciers have undergone accelerated mass loss during the past 20 a; only those on the northeastern Pamir Plateau exhibit a weak positive mass balance. Observations of typical monitored glaciers also reveal intensified melting and retreat, consistent with regional trends. In light of the recent acceleration of glacier shrinkage in Tajikistan, focused measures should be implemented to strengthen glacier monitoring, enhance public awareness of glacier preservation, and promote the sustainable development and utilization of glacier tourism. These findings bridge the knowledge gap regarding the spatiotemporal dynamics of Tajikistan’s glaciers over recent decades and provide essential data support for regional water resource management
GABA-independent activation of GABAB receptor by mechanical forces
No full textInternational audienceThe heterodimeric GABAB receptor, composed of GB1 and GB2 subunits, is a metabotropic G protein-coupled receptor (GPCR) activated by the neurotransmitter GABA. GABA binds to the extracellular domain of GB1 to activate G proteins through GB2. Here we show that GABAB receptors can be activated by mechanical forces, such as traction force and shear stress, in a GABA-independent manner. This GABA-independent mechano-activation of GABAB receptor is mediated by a direct interaction between integrins and the extracellular domain of GB1, indicating that GABAB receptor and integrin form a mechano-transduction complex. Mechanistically, shear stress promotes the binding of integrin to GB1 and induces an allosteric re-arrangement of GABAB receptor transmembrane domains towards an active conformation, culminating in receptor activation. Furthermore, we demonstrate that shear stress-induced GABAB receptor activation plays a crucial role in astrocyte remodeling. These findings reveal a role of GABAB receptor in mechano-transduction, uncovering a ligand-independent activation mechanism for GPCRs
A Cold-Sensing Receptor Encoded by a Glutamate Receptor Gene
No full textIn search of the molecular identities of cold-sensing receptors, we carried out an unbiased genetic screen for cold-sensing mutants in C. elegans and isolated a mutant allele of glr-3 gene that encodes a kainate-type glutamate receptor. While glutamate receptors are best known to transmit chemical synaptic signals in the CNS, we show that GLR-3 senses cold in the peripheral sensory neuron ASER to trigger cold-avoidance behavior. GLR-3 transmits cold signals via G protein signaling independently of its glutamate-gated channel function, suggesting GLR-3 as a metabotropic cold receptor. The vertebrate GLR-3 homolog GluK2 from zebrafish, mouse, and human can all function as a cold receptor in heterologous systems. Mouse DRG sensory neurons ex- prc GluK2, and GluK2 knockdown in these neurons suppresses their sensitivity to cold but not cool temperatures. Our study identifies an evolutionarily conserved cold receptor, revealing that a central chemical receptor unexpectedly functions as a thermal receptor in the periphery
