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  • MDPI AG  (7)
  • 1
    Online Resource
    Online Resource
    Soil Compressibility and Resilience Based on Uniaxial Compression Loading Test in Response to Soil Water Suction and Soil Organic Matter Content in Northeast China
    MDPI AG ; 2022
    In:  Sustainability Vol. 14, No. 5 ( 2022-02-24), p. 2620-
    Details
    In: Sustainability, MDPI AG, Vol. 14, No. 5 ( 2022-02-24), p. 2620-
    Abstract: Due to the widespread use of heavy machinery, improper soil tillage practices, and insufficient soil organic materials input, soil compaction has become a major issue affecting soil function in modern agriculture and the sustainability of the environment. The aim of the present study was to evaluate the responses of soil mechanical parameters to soil water content and soil organic matter content (SOM), and to investigate the physical properties of nine disturbed soils in a black soil region in Northeast China. The soil samples were capillary saturated and subjected to 6, 10, 100, 600, and 800 kPa soil water suction (SWS), and pre-compression stress (σp), compression index (Cc), and decompression index (Dc) were measured. SWS and SOM, and their interaction, significantly influenced the mechanical parameters. σp increased with an increase in SWS until 600 kPa, while Dc exhibited an opposite trend with an increase in SWS. Cc had a peak value at SWS of 100 kPa. All mechanical parameter values were higher under high SOM than under low SOM. σp, Cc, and Dc were influenced variably by different soil physicochemical factors. Structural equation modeling results revealed that soil mechanical parameters were directly and indirectly influenced by soil texture and mean weight diameter of aggregates, in addition to SOM and SWS. According to the results of the present study, based on soil mechanical and physical properties, increasing SOM and ensuring suitable soil water content during tillage could be applied as management strategies to minimize further soil compaction and improve soil resilience, and thus promote the sustainable development of agriculture in Northeast China.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    URL: Article
    DOI: 10.3390/su14052620
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2518383-7
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  • 2
    Online Resource
    Online Resource
    Influences of MJO on the Diurnal Variation and Associated Offshore Propagation of Rainfall near Western Coast of Sumatra
    MDPI AG ; 2022
    In:  Atmosphere Vol. 13, No. 2 ( 2022-02-16), p. 330-
    Details
    In: Atmosphere, MDPI AG, Vol. 13, No. 2 ( 2022-02-16), p. 330-
    Abstract: Madden-Julian Oscillation (MJO) plays an important role in modulating precipitation at Maritime Continent (MC) not only on a larger scale, but also in the diurnal cycle. Diurnal rainfall offshore propagation is one of the most evident features near coasts. This study investigates the impacts of MJO on diurnal rainfall and its offshore propagation at the western coast of Sumatra during boreal winters using ERA5 reanalysis. The real-time multivariate MJO (RMM) index was applied to locate the active MJO convection through eight different phases, in the western hemisphere and Africa in P8–P1, at the Indian Ocean in P2–P3, at MC in P4–P5, and the western Pacific Ocean in P6–P7. The rainfall characteristics, including the daily rate, the absolute and normalized diurnal variation amplitudes, and the strengths of diurnal offshore propagation, not only depend on active/inactive MJO stages but also vary under different MJO phases, through the combined modulations of large-scale backgrounds and local-scale land–sea circulations. The offshore rainfall propagation is associated with meso-large-scale gravity waves generated from land–sea thermal contrast and thus is affected by the radiation effect of cloud under different MJO phases. The stronger wave signals in P8–P1 and P6–P7 enhance the diurnal rainfall variation amplitudes away from the coast, while the strong coupling of moist convection with gravity waves contributes greatly to the diurnal rainfall cycle in P2–P3.
    Type of Medium: Online Resource
    ISSN: 2073-4433
    URL: Article
    DOI: 10.3390/atmos13020330
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2605928-9
    SSG: 23
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  • 3
    Online Resource
    Online Resource
    Effect of GABA-T on Reproductive Function in Female Rats
    MDPI AG ; 2020
    In:  Animals Vol. 10, No. 4 ( 2020-03-27), p. 567-
    Details
    In: Animals, MDPI AG, Vol. 10, No. 4 ( 2020-03-27), p. 567-
    Abstract: This study explored the role of γ-aminobutyric acid transaminase (GABA-T) in the puberty and reproductive performance of female rats. Immunofluorescence technique, quantitative real-time PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the distribution of GABA-T and the expression of genes and hormones in female rats, respectively. The results showed that GABA-T was mainly distributed in the arcuate nucleus (ARC), paraventricular nucleus (PVN) and periventricular nucleus (PeN) of the hypothalamus, and in the adenohypophysis, ovarian granulosa cells and oocytes. Abat mRNA level at 28 d was lowest in the hypothalamus and the pituitary; at puberty, it was lowest in the ovary. Abat mRNA level was highest in adults in the hypothalamus; at infancy and puberty, it was highest in the pituitary; and at 21 d it was highest in the ovary. After vigabatrin (GABA-T irreversible inhibitor) was added to hypothalamus cells, the levels of Abat mRNA and Rfrp-3 mRNA were significantly reduced, but Gnrh mRNA increased at the dose of 25 and 50 μg/mL; Kiss1 mRNA was significantly increased but Gabbr1 mRNA was reduced at the 50 μg/mL dose. In prepubertal rats injected with vigabatrin, puberty onset was delayed. Abat mRNA, Kiss1 mRNA and Gnrh mRNA levels were significantly reduced, but Rfrp-3 mRNA level increased in the hypothalamus. Vigabatrin reduced the concentrations of GABA-T, luteinizing hormone (LH) and progesterone (P4), and the ovarian index. Lactation performance was reduced in adult rats with vigabatrin treatment. Four hours after vigabatrin injection, the concentrations of GABA-T and LH were significantly reduced in adult and 25 d rats, but follicle-stimulating hormone (FSH) increased in 25 d rats. In conclusion, GABA-T affects the reproductive function of female rats by regulating the levels of Gnrh, Kiss1 and Rfrp-3 in the hypothalamus as well as the concentrations of LH and P4.
    Type of Medium: Online Resource
    ISSN: 2076-2615
    URL: Article
    DOI: 10.3390/ani10040567
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2606558-7
    SSG: 23
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  • 4
    Online Resource
    Online Resource
    Local-Scale Horizontal CO2 Flux Estimation Incorporating Differential Absorption Lidar and Coherent Doppler Wind Lidar
    MDPI AG ; 2022
    In:  Remote Sensing Vol. 14, No. 20 ( 2022-10-14), p. 5150-
    Details
    In: Remote Sensing, MDPI AG, Vol. 14, No. 20 ( 2022-10-14), p. 5150-
    Abstract: A micro-pulse lidar system incorporating differential absorption lidar (DIAL) and coherent Doppler wind lidar (CDWL) is proposed and demonstrated. Due to the high signal-to-noise ratio (SNR) of the superconducting nanowire single-photon detector (SNSPD), the DIAL channel achieves high sensitivity in CO2 measurement. Meanwhile, the CDWL channel is used to obtain the horizontal wind field. In the process of the optimization and calibration of the DIAL receiver, specifically, mode scrambling and temperature control of the connecting fiber between the telescope and the SNSPD enhance the stability and robustness of the system. Horizontal scanning of the CO2 concentration and the wind field is carried out in a 6 km range over a scanning span of 60° with a radial resolution of 150 m and 15 s. The results show that the hybrid lidar system captures the spatial distribution of CO2 concentration and the wind field simultaneously. The horizontal net CO2 flux in a radius of 6 km is estimated by integrating the CO2 concentration and the wind transport vector, indicating different characteristics of horizontal net CO2 fluxes in an industrial area, a university campus, and a park. During most of the experiment, CO2 flux remained positive in the industrial area, but balances fell to nearly zero on the campus and in the park. The horizontal net fluxes averaged over 24 h in the three areas are 3.5 × 105 ppm·m2·s−1, 0.7 × 105 ppm·m2·s−1, and 0.1 × 105 ppm·m2·s−1.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    URL: Article
    DOI: 10.3390/rs14205150
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2513863-7
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  • 5
    Online Resource
    Online Resource
    Denoising Algorithm for the FY-4A GIIRS Based on Principal Component Analysis
    MDPI AG ; 2019
    In:  Remote Sensing Vol. 11, No. 22 ( 2019-11-19), p. 2710-
    Details
    In: Remote Sensing, MDPI AG, Vol. 11, No. 22 ( 2019-11-19), p. 2710-
    Abstract: The Geostationary Interferometric Infrared Sounder (GIIRS) is the first high-spectral resolution advanced infrared (IR) sounder onboard the new-generation Chinese geostationary meteorological satellite FengYun-4A (FY-4A). The GIIRS has 1650 channels, and its spectrum ranges from 700 to 2250 cm−1 with an unapodized spectral resolution of 0.625 cm−1. It represents a significant breakthrough for measurements with high temporal, spatial and spectral resolutions worldwide. Many GIIRS channels have quite similar spectral signal characteristics that are highly correlated with each other in content and have a high degree of information redundancy. Therefore, this paper applies a principal component analysis (PCA)-based denoising algorithm (PDA) to study simulation data with different noise levels and observation data to reduce noise. The results show that the channel reconstruction using inter-channel spatial dependency and spectral similarity can reduce the noise in the observation brightness temperature (BT). A comparison of the BT observed by the GIIRS (O) with the BT simulated by the radiative transfer model (B) shows that a deviation occurs in the observation channel depending on the observation array. The results show that the array features of the reconstructed observation BT (rrO) depending on the observation array are weakened and the effect of the array position on the observations in the sub-center of the field of regard (FOR) are partially eliminated after the PDA procedure is applied. The high observation and simulation differences (O-B) in the sub-center of the FOR array notably reduced after the PDA procedure is implemented. The improvement of the high O-B is more distinct, and the low O-B becomes smoother. In each scan line, the standard deviation of the reconstructed background departures (rrO-B) is lower than that of the background departures (O-B). The observation error calculated by posterior estimation based on variational assimilation also verifies the efficiency of the PDA. The typhoon experiment also shows that among the 29 selected assimilation channels, the observation error of 65% of the channels was reduced as calculated by the triangle method.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    URL: Article
    DOI: 10.3390/rs11222710
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2513863-7
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  • 6
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    Online Resource
    Synthesis and Mechanism Study of Temperature- and Salt-Resistant Amphoteric Polyacrylamide with MAPTAC and DTAB as Monomers
    MDPI AG ; 2022
    In:  Processes Vol. 10, No. 8 ( 2022-08-22), p. 1666-
    Details
    In: Processes, MDPI AG, Vol. 10, No. 8 ( 2022-08-22), p. 1666-
    Abstract: The failure of thickeners at high temperature results in gelled acid acidification fracturing. To solve the problem, 8 kinds of polymers were synthesized by free radical polymerization of aqueous solution using AM, AMPS, NaAMPS, MAPTAC, DTAB and NVP as raw materials. The polymer was characterized by infrared spectroscopy and viscosity-average molecular weight, and the temperature resistance, rheology, salt resistance and shear resistance of the polymer solution were compared, and the mechanism was analyzed. The results show that the viscosity of GTY−2 is 181.52 mPa·s, and the viscosity loss rate is 56.89% at 180 °C and 100 s−1, and its temperature resistance is the best. Meanwhile, the viscosity retention rate of GTY−2 is 84.58% after 160 min shear, showing the strongest shear resistance. The viscosity loss rate of GTY−1 in 20% hydrochloric acid solution is 80.88%, and its acid resistance is stronger than that of GTY−2. Moreover, due to the amphiphilicity of DTAB, the molecular hydration film becomes thicker, and the salt resistance of GTY−2 is lower than that of GTY−1. The experimental results show that GTY−1 and GTY−2 have good temperature resistance, salt resistance, acid resistance and shear resistance, and can be used as thickeners for acid fracturing with thickened acid to improve the effect of acid fracturing under high temperature conditions.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    URL: Article
    DOI: 10.3390/pr10081666
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720994-5
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  • 7
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    Online Resource
    An Analysis of Vocal Features for Parkinson’s Disease Classification Using Evolutionary Algorithms
    MDPI AG ; 2022
    In:  Diagnostics Vol. 12, No. 8 ( 2022-08-16), p. 1980-
    Details
    In: Diagnostics, MDPI AG, Vol. 12, No. 8 ( 2022-08-16), p. 1980-
    Abstract: Parkinson’s Disease (PD) is a brain disorder that causes uncontrollable movements. According to estimation, roughly ten million individuals worldwide have had or are developing PD. This disorder can have severe consequences that affect the patient’s daily life. Therefore, several previous works have worked on PD detection. Automatic Parkinson’s Disease detection in voice recordings can be an innovation compared to other costly methods of ruling out examinations since the nature of this disease is unpredictable and non-curable. Analyzing the collected vocal records will detect essential patterns, and timely recommendations on appropriate treatments will be extremely helpful. This research proposed a machine learning-based approach for classifying healthy people from people with the disease utilizing Grey Wolf Optimization (GWO) for feature selection, along with Light Gradient Boosted Machine (LGBM) to optimize the model performance. The proposed method shows highly competitive results and has the ability to be developed further and implemented in a real-world setting.
    Type of Medium: Online Resource
    ISSN: 2075-4418
    URL: Article
    DOI: 10.3390/diagnostics12081980
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662336-5
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