The present situation and problems of enviromental economic policy in China are discussed,and the measures to improve environmental ecomomic policy are put forward.
Hyperspectral unmixing decomposes the observed mixed spectra into a collection of constituent pure material signatures and the associated fractional abundances. Because of the universal modeling ability of neural networks, deep learning (DL) techniques are gaining prominence in solving hyperspectral analysis tasks. The autoencoder (AE) network has been extensively investigated in linear blind source unmixing. However, the linear mixing model (LMM) may fail to provide good unmixing performance when the nonlinear mixing effects are nonnegligible in complex scenarios. Considering the limitations of LMM, we propose an unsupervised nonlinear spectral unmixing method, based on autoencoder architecture. Firstly, a deep neural network is employed as the encoder to extract the low-dimension feature of the mixed pixel. Then, the generalized bilinear model (GBM) is used to design the decoder, which has a linear mixing part and a nonlinear mixing one. The coefficient of the bilinear mixing part can be adjusted by a set of learnable parameters, which makes the method perform well on both nonlinear and linear data. Finally, some regular terms are imposed on the loss function and an alternating update strategy is utilized to train the network. Experimental results on synthetic and real datasets verify the effectiveness of the proposed model and show very competitive performance compared with several existing algorithms.
Leaf area index (LAI) is a key parameter for the study of biogeochemical cycles in ecosystems. Remote sensing techniques have been widely used to estimate LAIs in a wide range of vegetation types. However, limited by the sensor detection capability, considerable fewer studies investigated the layered estimation of LAIs in the vertical direction, which can significantly affect the precision evaluation of vegetation biophysical and biochemical processes. This study tried to generate a kind of pseudo large footprint waveform from the small footprint full-waveform airborne LiDAR data by an aggregation approach. The layered distribution of canopy heights and LAIs were successfully retrieved based on the large footprint waveform data in an agricultural landscape of orchards with typical multi-layer vegetation covers. The Gaussian fitting was conducted on the normalized large footprint waveforms to identify the vertical positions for different vegetation layers. Then, the gap theory was applied to retrieve the layered LAIs. Statistically significant simple linear regression models were fitted between the LiDAR-retrieved and field-observed values for the canopy heights and LAIs in different layers. Satisfactory results were obtained with a root mean square error of 0.36 m for the overstorey canopy height (R2 = 0.82), 0.29 m for the understory canopy height (R2 = 0.76), 0.28 for overstorey LAI (R2 = 0.75), 0.40 for understory LAI (R2 = 0.64), and 0.38 for total LAI (R2 = 0.69), respectively. To conclude, estimating the layered LAIs in the multi-layer agriculture orchards from the pseudo large footprint waveforms is feasible and the estimation errors are acceptable, which will provide some new ideas and methods for the quantitative remote sensing with vegetation.
Salvia miltiorrhiza is a perennial herbaceous plant for traditional Chinese medicine. It has been extensively applied for many hundred years to treat various diseases (Su et al. 2015). It is also a kind of important cash crop that is widely cultivated in southern Shaanxi province. In June of 2021, in a field in Luonan County, Shaanxi Province, some S. miltiorrhiza plants with stunting and leaf wilting symptoms were observed. The diseased plants exhibited a large number of globular galling on the secondary and tertiary roots. The symptoms were typical of infection by root-knot nematodes. Population densities of second-stage juveniles (J2s) ranged from 330 to 650 per 100 cm3. To identify the species of the root-knot nematodes, J2s and males were collected from the soil in the root zone, and females were isolated from diseased roots. The perineal patterns of females (n = 12) were round-shaped, with low dorsal arches, obvious lateral lines, and characteristic small punctations near anus. Morphological measurements of females (n = 20) included body length (L) = 565.25 ± 33.9 (503.35 - 632.47) μm, body width (BW) = 420.00 ± 21.28 (378.27 - 452.51) μm, stylet = 11.11 ± 0.73 (10.05-12.29) μm, dorsal pharyngeal gland orifice to stylet base (DGO) = 4.69 ± 0.45 (3.82-5.32) μm, vulval slit length = 21.1 ± 1.33 (18.38-22.96) μm, and vulval slit to anus distance = 15.76 ± 1.24 (13.38-17.45) μm. The morphological characters of males (n = 7): L = 1098.14 ± 82.99 (962.83-1193.87) μm, BW = 28.44 ± 1.18 (26.59-29.83) μm, stylet = 18.27 ± 0.97 (16.57-19.28) μm, DGO = 4.89 ± 0.62 (3.82-5.68) μm, and spicule length = 24.04 ± 1.80 (21.30-26.71) μm. The key morphometrics of J2s: L = 380.24 ± 18.24 (354.43-423.13) μm, BW = 13.94 ± 0.70 (12.88-15.34) μm, stylet = 11.82 ± 0.49 (10.96-12.61) μm, DGO = 3.68 ± 0.42 (3.09-4.56) μm, tail length = 55.42 ± 5.81 (46.97-67.03) μm, and hyaline tail terminus = 13.79 ± 1.24 (12.0-16.51) μm. These morphological characteristics are consistent with Meloidogyne hapla as described by Whitehead (1968). Ten individual females were transferred to ten different tubes for DNA extraction. The DNA extraction followed the method described by Htay et al. (2016). The species-specific primers JMV1 (5'-GGATGGCGTGCTTTCAAC-3') and JMV (5'-AAAAATCCCCTCGAAAAATCCACC-3') were used for the identification of M. hapla (Adam et al. 2007). A single 440 bp fragment was amplified by this pair of primers, confirming their identities as M. hapla. To confirm species identification, the ITS region was amplified using the primers 18S/26S (5'-TTGATTACGTCCCTGCCCTTT-3'/5'-TTTCACTCGCCGTTACTAAGG-3') (Vrain et al. 1992). The sequence from the ITS region was 768 bp (GenBank Accession No. OM049198) and was 100% identical to the sequences of M. hapla (GenBank Accession Nos. MT249016 and KJ572385). The mitochondrial DNA (mtDNA) region between COII and the lRNA gene was amplified using primers C2F3 (5'-GGTCAATGTTCAGAAATTTGTGG-3') and 1108 (5'-TACCTTTGACCAATCACGCT-3') (Powers and Harris, 1993). A fragment of 529 bp was obtained and the sequence (GenBank Accession No. OM055828) was 100% identical to the known sequence of M. hapla from Taiwan (GenBank Accession No. KJ598134). An infection test was conducted in greenhouse conditions. Six 2-month-old S. miltiorrhiza plants were individually maintained in 12-cm diameter, 10-cm deep plastic pots containing sterilized soil and each plant was inoculated with 3000 J2s hatched from egg masses of collected M. hapla samples. Two non-inoculated S. miltiorrhiza plants served as negative controls. After 60 days, inoculated plants exhibited galled roots similar to those observed in the field. Many galls (61.33 ± 8.52) and egg masses (26.17 ± 4.79) were found on each root system. The nematode reproduction factor (RF = final population/initial population) was 4.5. No symptoms were observed in control plants. The nematode was reisolated from root tissue and identified to be M. hapla with its sequence-specific primers JMV1/JMV. These results confirmed that the nematode population could infect S. miltiorrhiza. To our knowledge, this is the first time of natural infection of S. miltiorrhiza with M. hapla in China. Including S. miltiorrhiza, the medicinal ingredients of many traditional Chinese herbal medicines were extracted from the roots of the plants. The infection of root-knot nematode will cause a serious decline in the quality of Chinese medicinal materials. Therefore, it is necessary to identify the species of root-knot nematode in different Chinese herbal medicines.
As a rapid developing area, Changping in Beijing, China, the change of land use and land cover(LUCC) had occurred at large scale in the recent 20 years. Remote sensing had provided the approach to monitoring LUCC and the environment response. The paper focus on monitoring LUCC and quantitative analysis of the thermal environment response. Based on the multi-temporal LandsatETM remote sensing images in 1999 and 2006, the earth surface brightness tempreture had been obtained by retrieving from LandsatTM6. The regional land use change and its spatio-temporal thermal environment evolution were analyzed with ENVI4.7 and Arc GIS 9.2. The research results showed that the land use changed evidently from 1999 to 2006. The regional urban expanding and the spatio-temporal thermal environment evolution was consistent from 1999 to 2006. By comparing the contrbution from the different land use types to the urban thermal environment effect, it was discovered that forest land was the largest contributor for the low area. The proportion of forest land decreased in the low temperature areas, and the proportion of urban land increased in high temperature area from 1999 to 2006. The urban heat island effect was obvious. The nakes arable land resulted the high temperature areas. The forest land and the agricultural land with the crop was helpful for the lower temperature areas.
The general situation of system composition and safety management of high-speed railway terminal is investigated and a comprehensive evaluation index system of operational security is established on the basis of railway laws and regulations and previous research results to evaluate the operational security management of the high-speed railway terminal objectively and scientifically. Index weight is determined by introducing interval eigenvalue method (IEM), which aims to reduce the dependence of judgment matrix on consistency test and improve judgment accuracy. Operational security status of a high-speed railway terminal in northwest China is analyzed using the traditional model of fuzzy comprehensive evaluation, and a general technique idea and references for the operational security evaluation of the high-speed railway terminal are provided. IEM is introduced to determine the weight of each index, overcomes shortcomings of traditional analytic hierarchy process (AHP) method, and improves the accuracy and scientificity of the comprehensive evaluation. Risk factors, such as terrorist attacks, bad weather, and building fires, are intentionally avoided in the selection of evaluation indicators due to the complexity of risk factors in the operation of high-speed railway passenger stations and limitation of the length of the paper. However, such risk factors should be considered in the followup studies.
The conflict between the integration program of coal resources and the natural protection of Dusong Nature Reserve in Fugu County has been discussed.Accordingly,suitable environmental impact assessment program or ideas was proposed to achieve a win-win situation of both the reasonable development of coal resources and sustainable development ecological environment.
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