22 research outputs found

    Research on the influence of the nature of the weathered bedrock zone on the roof water bursting and sand bursting: taking Zhaogu No. 1 Mine as an example

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    Based on Zhaogu No. 1 Mine’s characters that are the overlying thick alluvium, multi-aquifers (groups) and thin bedrock, the water pressure of the gravel aquifer under the alluvial layer reaches 4.0 MPa, defined a high-pressure aquifer. To determine the influence of bedrock properties on roof water inrush and sand bursting, and ensure the normal mining around the thin bedrock area under groups, there were tests, point loading, dry saturated water absorption rate and indoor disintegration, of bedrock samples taken from hydrological survey holes to determine those properties and influence on retaining sand-proof pillars by analyzing the variation curves of various indexes of them with depth. The experiments’ results showed that the weathering depth of bedrock exceeds 20 m; the dry saturated water absorption rate of mudstone in the vertical depth ranging of 0−6.5 m from the bottom interface of the alluvial layer is greater than 15%. The mudstone exposed to water features muddy disintegration, broken rock fragments and mud blocks, which means it is good water-proof performance of effective bridging mining cracks and a protective layer for waterproof coal pillars; as the strength of weathered mudstone below the alluvial layer 0 to 11.4 m is lower than it of the fine gravel aquifer in the lower that of 4.0 MPa, the sand control coal pillar’s protective layer that is greater more than 11.4 m is cannot be entirely composed of weathered mudstone; due to strong resistance to disintegration and lower dry saturated water absorption rate of sandstone, the protective layer cannot be entirely composed of weathered sandstone. The compressive strength of weathered sandstone, when it is higher than 4.0 MPa, can effectively resist the overlying water head pressure

    Soil nitrogen and carbon storages and carbon pool management index under sustainable conservation tillage strategy

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    Agricultural practices are significant to increase the soil nitrogen and organic carbon sequestration to adapt and mitigate the climate change in a recent climate change scenario. With this background, we carried out research in the Longzhong Loess Plateau region of China. This research was conducted under a randomized complete block design, with three replicates. Adopt the method of combining outdoor positioning field test with indoor index measurement to explore the soil bulk density (BD), nitrogen components (viz., nitrate nitrogen (NO3−-N), ammonia nitrogen (NH4+-N), total nitrogen (TN), microbial biomass nitrogen (MBN) and nitrogen storage (NS), and carbon components [viz., soil organic carbon (SOC), easily oxidized organic carbon (EOC), microbial biomass carbon (MBC) and carbon storage (CS), carbon pool index (CPI), carbon pool activity (A) and carbon pool activity index (AI) and carbon pool management index (CPMI)] and C/N, ratio under different tillage practices [namely., conventional tillage (CT), no tillage (NT), straw mulch with conventional tillage (CTS) and straw mulch with no tillage (NTS)]. Our results depicted that different conservation tillage systems significantly increased soil BD over conventional tillage. Compared with CT, the NTS, CTS and NT reduced soil NO3−-N, increased the soil NH4+-N, TN, MBN and NS, among them, NS under NTS, CTS and NT treatment was 25.0, 14.8 and 13.1% higher than that under CT treatment, respectively. Additionally, conservation tillage significantly increased SOC, EOC, MBC, CS, CPI, AI, CPMI and C/N, ratio than CT. Inside, CS under NTS, CTS and NT treatment was 19.4, 12.1 and 13.4% higher than that under CT treatment, respectively. Moreover, during the 3-year study period, the CPMI under NTS treatment was the largest (139.26, 140.97, and 166.17). Consequently, we suggest that NTS treatment was more sustainable strategy over other investigated conservation tillage practices and should be recommended as climate mitigation technique under climate change context

    A Compact Unconditionally Stable Method for Time-Domain Maxwell's Equations

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    Higher order unconditionally stable methods are effective ways for simulating field behaviors of electromagnetic problems since they are free of Courant-Friedrich-Levy conditions. The development of accurate schemes with less computational expenditure is desirable. A compact fourth-order split-step unconditionally-stable finite-difference time-domain method (C4OSS-FDTD) is proposed in this paper. This method is based on a four-step splitting form in time which is constructed by symmetric operator and uniform splitting. The introduction of spatial compact operator can further improve its performance. Analyses of stability and numerical dispersion are carried out. Compared with noncompact counterpart, the proposed method has reduced computational expenditure while keeping the same level of accuracy. Comparisons with other compact unconditionally-stable methods are provided. Numerical dispersion and anisotropy errors are shown to be lower than those of previous compact unconditionally-stable methods

    A Parallel CE-LOD-FDTD Model for Instrument Landing System Signal Disturbance Analyzing

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    Ceftriaxone inhibits stress‐induced bladder hyperalgesia and alters cerebral micturition and nociceptive circuits in the rat: A multidisciplinary approach to the study of urologic chronic pelvic pain syndrome research network study

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    AimsEmotional stress plays a role in the exacerbation and development of interstitial cystitis/bladder pain syndrome (IC/BPS). Given the significant overlap of brain circuits involved in stress, anxiety, and micturition, and the documented role of glutamate in their regulation, we examined the effects of an increase in glutamate transport on central amplification of stress-induced bladder hyperalgesia, a core feature of IC/BPS.MethodsWistar-Kyoto rats were exposed to water avoidance stress (WAS, 1 hour/day x 10 days) or sham stress, with subgroups receiving daily administration of ceftriaxone (CTX), an activator of glutamate transport. Thereafter, cystometrograms were obtained during bladder infusion with visceromotor responses (VMR) recorded simultaneously. Cerebral blood flow (CBF) mapping was performed by intravenous injection of [14 C]-iodoantipyrine during passive bladder distension. Regional CBF was quantified in autoradiographs of brain slices and analyzed in three dimensional reconstructed brains with statistical parametric mapping.ResultsWAS elicited visceral hypersensitivity during bladder filling as demonstrated by a decreased pressure threshold and VMR threshold triggering the voiding phase. Brain maps revealed stress effects in regions noted to be responsive to bladder filling. CTX diminished visceral hypersensitivity and attenuated many stress-related cerebral activations within the supraspinal micturition circuit and in overlapping limbic and nociceptive regions, including the posterior midline cortex (posterior cingulate/anterior retrosplenium), somatosensory cortex, and anterior thalamus.ConclusionsCTX diminished bladder hyspersensitivity and attenuated regions of the brain that contribute to nociceptive and micturition circuits, show stress effects, and have been reported to demonstrated altered functionality in patients with IC/BPS. Glutamatergic pharmacologic strategies modulating stress-related bladder dysfunction may be a novel approach to the treatment of IC/BPS

    Changes in Soil Properties and Crop Yield under Sustainable Conservation Tillage Systems in Spring Wheat Agroecosystems

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    The cultivated soils in several semi-arid areas have very low organic matter due to climatic constraints that limit primary crop yield. Conservation tillage systems, outlined here as no tillage, no tillage with straw return and straw incorporation into the field, have been accepted as capable systems that preserve soil’s resources and sustain soil productivity. However, in semi-arid climates, there is presently no knowledge about the influence of different conservation tillage techniques on soil’s physical, chemical and biological properties at different soil depths in spring wheat fields and only little information about spring wheat yield in these management systems. Therefore, the present study was carried out with the objective of examining the impact of conservation tillage systems on soil properties (physical, chemical and biological) and spring wheat yield. The three conservation tillage treatments consisted of no tillage system (NT), wheat stubble return with no tillage (NTS) and straw incorporation with conventional tillage (CTS), as well as one conventional tillage (CT) control treatment, which were evaluated under randomized complete block design with three replications. The three conservation tillage treatments were compared with the conventional tillage control. Conservation tillage significantly increased the bulk density, gravimetric water content, water storage, hydraulic conductivity and soil aggregates and decreased the pore space and soil temperature compared to CT; however, no significant difference was found in the case of field capacity. Soil chemical properties in the 0–40 cm soil layer increased with conservation tillage compared to CT. Conservation tillage also notably increased the soil microbial counts, urease, alkaline phosphatase, invertase, cellulase and catalase activities relative to CT. Microbial biomasses (carbon and nitrogen) and wheat yield significantly elevated under conservation tillage compared to CT. Therefore, conservation tillage could significantly improve soil properties and maintain wheat yield for the research zone

    Effects of water avoidance stress on peripheral and central responses during bladder filling in the rat: A multidisciplinary approach to the study of urologic chronic pelvic pain syndrome (MAPP) research network study - Fig 2

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    <p><b>(A) Representative examples of visceromotor reflex (VMR)</b> in the control and WAS animals at each level of bladder pressure between 0 and 40 cmH<sub>2</sub>O. <b>(B) During isotonic bladder distension, VMR AUC (VMR +/- standard error) in WAS significantly increased compared to controls</b> at 20 cmH<sub>2</sub>O (P = 0.03). VMR: visceromotor reflex. AUC: area under the curve. Note different scales used at different pressure levels. WAS: water avoidance stress.</p

    Seed correlation of functional activity across the whole brain during bladder filling.

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    <p>WAS compared to control rats show greater functional connectivity of <b>(row 1)</b> the posterior cingulate to the parabrachial/Barrington nucleus complex, <b>(row 2)</b> the posterior insula to anterior secondary motor cortex (M2), and <b>(row 3)</b> the Barrington nucleus to the anterior, dorsal midline thalamus (mediodorsal, MD; paraventricular, PVN), as well as the ventrobasilar thalamic complex, primary and secondary somatosensory cortex (S1, S2) and retrosplenial cortex.</p

    Differences in functional brain activation during bladder filling of WAS rats compared to controls.

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    <p><b>Left column:</b> Statistical parametric maps showing significant difference (P < 0.05 for clusters of greater than 100 contiguous significant voxels) in brain activation in sedated WAS rats compared to controls are superimposed on gray-scale coronal sections showing the rCBF distribution of the template brain. <b>Right column:</b> ROI analysis shows group mean rCBF (± S.E.) for select brain regions in the micturition circuit, in which rCBF in each animal was normalized by its whole brain mean perfusion. * P < 0.05, **P < 0.005 for clusters of greater than 100 significant, contiguous voxels. Abbreviations: Cx (cortex), PAG (periaqueductal gray), PB (parabrachial nucleus).</p
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