A major research plan entitled “Integrated research on the ecohydrological process of the Heihe River Basin” was launched by the National Natural Science Foundation of China in 2010. One of the key aims of this research plan is to establish a research platform that integrates observation, data management, and model simulation to foster twenty-first-century watershed science in China. Based on the diverse needs of interdisciplinary studies within this research plan, a program called the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) was implemented. The overall objective of HiWATER is to improve the observability of hydrological and ecological processes, to build a world-class watershed observing system, and to enhance the applicability of remote sensing in integrated ecohydrological studies and water resource management at the basin scale. This paper introduces the background, scientific objectives, and experimental design of HiWATER. The instrumental setting and airborne mission plans are also outlined. The highlights are the use of a flux observing matrix and an eco-hydrological wireless sensor network to capture multiscale heterogeneities and to address complex problems, such as heterogeneity, scaling, uncertainty, and closing water cycle at the watershed scale. HiWATER was formally initialized in May 2012 and will last four years until 2015. Data will be made available to the scientific community via the Environmental and Ecological Science Data Center for West China. International scientists are welcome to participate in the field campaign and use the data in their analyses.
The Watershed Allied Telemetry Experimental Research (WATER) is a simultaneous airborne, satellite‐borne, and ground‐based remote sensing experiment aiming to improve the observability, understanding, and predictability of hydrological and related ecological processes at a catchment scale. WATER consists of the cold region, forest, and arid region hydrological experiments as well as a hydrometeorology experiment and took place in the Heihe River Basin, a typical inland river basin in the northwest of China. The field campaigns have been completed, with an intensive observation period lasting from 7 March to 12 April, from 15 May to 22 July, and from 23 August to 5 September 2008: in total, 120 days. Twenty‐five airborne missions were flown. Airborne sensors including microwave radiometers at L, K, and Ka bands, imaging spectrometer, thermal imager, CCD, and lidar were used. Various satellite data were collected. Ground measurements were carried out at four scales, that is, key experimental area, foci experimental area, experiment site, and elementary sampling plot, using ground‐based remote sensing instruments, densified network of automatic meteorological stations, flux towers, and hydrological stations. On the basis of these measurements, the remote sensing retrieval models and algorithms of water cycle variables are to be developed or improved, and a catchment‐scale land/hydrological data assimilation system is being developed. This paper reviews the background, scientific objectives, experiment design, filed campaign implementation, and current status of WATER. The analysis of the data will continue over the next 2 years, and limited revisits to the field are anticipated.
[1] Agreement among instruments is very important for the Multi-Scale Observation Experiment on Evapotranspiration over heterogeneous land surfaces of The Heihe Watershed Allied Telemetry Experimental Research (HiWATER-MUSOEXE), particularly in regard to radiation and turbulent flux measurements. Before HiWATER-MUSOEXE was conducted, 20 eddy covariance (EC) system sets, 18 radiometer sets, and seven large aperture scintillometers (LASs) sets were intercompared over the Gobi desert between 14 and 24 May 2012. For radiometers, the four-component radiation measurements exhibited good agreement -the average root-mean-square error (RMSE) and mean relative error (MRE) for the net radiation were 10.38 W m À2 and 1.24%, respectively. With regard to the EC systems, the best consistency for sensible heat fluxes was found among CSAT3 sonic anemometers and Li7500A/Li7500/EC150 combinations (average RMSE, 12.30 W m À2 and MRE, À1.36%), followed by Gill sonic anemometers and Li7500A/Li7500 combinations when a proper angle of attack correction method was applied (average RMSE, 16.75 W m À2 and MRE, À5.52%). The sensible heat flux measured using different LASs agreed well with high correlation coefficients -the average RMSE and MRE values were 10.26 W m À2 and 5.48% for boundary layer scintillometer (BLS) 900, 16.32 W m À2 and 10.47% for BLS450, and 14.38 W m À2 and À3.72% for ZZLAS, respectively. The EC and LAS measurements were compared and agreed well over homogeneous underlying surfaces, which also indicated that the EC and LAS measurements would be comparable in the follow-up experiment. The intercomparison results can be used to determine instrument placement and are very helpful for subsequent data analysis.
GABA-mediated postsynaptic currents (IPSCs) were recorded from dopaminergic (DA) neurons of the ventral tegmental area (VTA) of rats, in acute brain slices, and from enzymatically or mechanically dissociated neurons. In young rats (3-10 d of age), where GABA is excitatory, glycine (1-3 M) and taurine (10 -30 M) increased the amplitude of evoked IPSCs (eIPSCs) and the frequency of spontaneous IPSCs (sIPSCs) but had minimal postsynaptic effects. Strychnine (1 M) blocked the action of glycine; when applied alone, it reduced the amplitude of eIPSCs and the frequency of sIPSCs, indicating a tonic facilitation of GABAergic excitation by some endogenous glycine agonist(s). In medium containing no Ca 2ϩ , or with Cd 2ϩ or tetrodotoxin added, the amplitude and especially the frequency of sIPSCs greatly diminished. In many cells, glycine had no effect on remaining miniature IPSCs, suggesting a preterminal site of glycine receptors (GlyRs). Fura-2 fluorescent imaging showed a glycine-induced increase of [Ca 2ϩ ] in nerve terminals (on DA neurons), which was suppressed by strychnine or 3 M -conotoxin MVIIA. Therefore, the presynaptic GlyR-mediated facilitation of GABAergic transmission seems to be mediated by N-and/or P/Q-type Ca 2ϩ channels. In older rats (22-30 d of age), where GABA causes inhibition, the effect of strychnine on GABAergic IPSCs was reversed to facilitation, indicating a tonic glycinergic inhibition of GABA release. Furthermore, glycine (1-3 M) reduced the amplitude of eIPSCs and the frequency of sIPSCs. Hence, the overall effect of the presynaptic action of glycine is to enhance the firing of DA cells, both in very young and older rats.
Research on land surface processes at the catchment scale has drawn much attention over the past few decades, and a number of watershed observatories have been established worldwide. The Heihe River Basin (HRB), which contains the second largest inland river in China, is an ideal natural field experimental area for investigation of land surface processes involving diverse landscapes and the coexistence of cold and arid regions. The Heihe Integrated Observatory Network was established in 2007. For long-term observations, a hydrometeorological observatory, ecohydrological wireless sensor network, and satellite remote sensing are now in operation. In 2012, a multiscale observation experiment on evapotranspiration over heterogeneous land surfaces was conducted in the midstream region of the HRB, which included a flux observation matrix, wireless sensor network, airborne remote sensing, and synchronized ground measurements. Under an open data policy, the datasets have been publicly released following careful data processing and quality control. The outcomes highlight the integrated research on land surface processes in the HRB and include observed trends, scaling methods, high spatiotemporal resolution remote sensing products, and model-data integration in the HRB, all of which are helpful to other endorheic basins in the "Silk Road Economic Belt." Henceforth, the goal of the Heihe Integrated Observatory Network is to develop an intelligent monitoring system that incorporates ground-based observatory networks, unmanned aerial vehicles, and multi-source satellites through the Internet of Things technology. Furthermore, biogeochemical processes observation will be improved, and the study of integrating ground observations, remote sensing, and large-scale models will be promoted further.
This work reports a facile strategy for the preparation of a novel well-defined brush copolymer with two different grafts distributed on the same unit along the backbone via combination of three controlled polymerization methods, ring-opening polymerization (ROP), ring-opening metathesis polymerization (ROMP), and atom transfer radical polymerization (ATRP) based on the synthesis of the heterotrifunctional inimer, 2-hydroxymethyl-3-(2-bromoisobutyryloxymethyl)-5-norbornene (NBE-OH/Br). ROP of ε-caprolactone initiated by NBE-OH/Br was carried out to generate macroinimer, norbornene-graft-poly(ε-caprolactone)/Br (NBE-g-PCL/ Br). The grafting-through strategy was then employed to construct the polymer backbone, poly(norbornene)graft-poly(ε-caprolactone)/Br (PNBE-g-PCL/Br) via ROMP of the norbornene-terminated macroinimer NBE-g-PCL/Br. Finally, the grafting-from route was used for the synthesis of amphiphilic grafted brush copolymer, poly(norbornene)-graft-poly(ε-caprolactone)/poly(2-(dimethylamino)ethyl methacrylate) (PNBE-g-PCL/PDMAE-MA) by ATRP of 2-(dimethylamino)ethyl methacrylate using bromo-functionalized ROMP product PNBE-g-PCL/Br as macroinitiators, containing one hydrophobic PCL graft and one hydrophilic PDMAEMA graft on each unit of the backbone.
Experimentally evoked seizures can activate the intrinsic mitochondrial cell death pathway, components of which are modulated in the hippocampus of patients with temporal lobe epilepsy. Bcl-2 family proteins are critical regulators of mitochondrial dysfunction, but their significance in this setting remains primarily untested. Presently, we investigated the mitochondrial pathway and role of anti-apoptotic Bcl-2 proteins using a mouse model of seizure-induced neuronal death. Status epilepticus was evoked in mice by intra-amygdala kainic acid, causing cytochrome c release, processing of caspases 9 and 7, and death of ipsilateral hippocampal pyramidal neurons. Seizures caused a rapid decline in hippocampal Bcl-w levels not seen for either Bcl-2 or Bcl-xl. To test whether endogenous Bcl-w was functionally significant for neuronal survival, we investigated hippocampal injury after seizures in Bcl-w-deficient mice. Seizures induced significantly more hippocampal CA3 neuronal loss and DNA fragmentation in Bcl-w-deficient mice compared with wild-type mice. Quantitative electroencephalography analysis also revealed that Bcl-w-deficient mice display a neurophysiological phenotype whereby there was earlier polyspike seizure onset. Finally, we detected higher levels of Bcl-w in hippocampus from temporal lobe epilepsy patients compared with autopsy controls. These data identify Bcl-w as an endogenous neuroprotectant that may have seizure
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