43 research outputs found

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30M⊙M_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    Optimal Selection Method for Sweet Spots in Low-Permeability Multilayered Reservoirs

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    Low-permeability oil reservoirs account for more than two-thirds of China’s proven reserves, and most of them are multilayered; the traditional sweet spots focus on single-layered reservoirs. The sweet spots of low-permeability reservoirs have two meanings: the geologically superior reservoir and the beneficial development of the reservoir. In this study, a concept of reservoir stratification coefficient is proposed to evaluate the characteristics of multilayered reservoirs, and three indicators are proposed, namely, reservoir stratification coefficient, energy storage coefficient, and stratigraphic coefficient, as the indicators of sweet spots of multilayered reservoirs. The three indicators are combined into a single indicator using a weighted approach, and the sweet spots can be identified based on the combined indicator. The Xiliu A area of the North China oilfield was selected for a case study. According to the structural, sedimentary, and reservoir characteristics of the block, combined with the development and production conditions, the Sha 3 Member I oil group was selected as the study object of sweet spots of the low-permeability reservoir. The results show that the reservoir stratification coefficient, energy storage coefficient, and stratigraphic coefficient proposed in this study are effective indicators for the preferential selection of sweet spots, which can reflect the longitudinal heterogeneity, energy storage size, and flow capacity of multilayered reservoirs. After a comparative analysis with actual blocks, it was found that the results obtained using the method are consistent with the actual capacity of the reservoir. The production capacity is high. The evaluation effect is ideal, and the applicability is good. Thus, this study provides a new technical method for the evaluation of similar multilayered reservoirs. The findings of this study can help for a better understanding of the development and production conditions and optimization basis of low-permeability reservoirs

    A New Well-Balanced Reconstruction Technique for the Numerical Simulation of Shallow Water Flows with Wet/Dry Fronts and Complex Topography

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    This study develops a new well-balanced scheme for the one-dimensional shallow water system over irregular bed topographies with wet/dry fronts, in a Godunov-type finite volume framework. A new reconstruction technique that includes flooded cells and partially flooded cells and preserves the non-negative values of water depth is proposed. For the wet cell, a modified revised surface gradient method is presented assuming that the bed topography is irregular in the cell. For the case that the cell is partially flooded, this paper proposes a special reconstruction of flow variables that assumes that the bottom function is linear in the cell. The Harten⁻Lax⁻van Leer approximate Riemann solver is applied to evaluate the flux at cell faces. The numerical results show good agreement with analytical solutions to a set of test cases and experimental results

    Sensitivity Analysis of Water-Alternating-COâ‚‚ Flooding for Enhanced Oil Recovery in High Water Cut Oil Reservoirs

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    The objective of this work is to investigate the effect of operational schemes, reservoir types and development parameters on both the amount of incremental oil produced and CO2 stored in high water cut oil reservoirs during CO2 water-alternating-gas (WAG) flooding by running compositional numerical simulator.The method used is the orthogonal experimental design method to optimize operation parameters, including CO2 slug size, ratio of CO2 slug size to water slug size (WAG ratio), CO2 injection rate, and voidage replacement ratio. The Net Present Value (NPV) was used as an objective function for economic analysis. Various 3-D heterogeneous reservoir models were built to investigate the impact of reservoir types and development parameters on CO2 flooding efficiency and storage capacity.The results indicate that as compared to inverted nine-spot pattern and inverted seven-spot pattern, five-spot pattern is more suitable for CO2 WAG flooding. The earlier water injection is switched to CO2, the more benefit can be obtained. Compared with CO2 injection cost and tax credit per ton of CO2 stored, oil price is considered as the most influential economic parameter on CO2 WAG flooding

    Global Transcriptome Analysis During Adipogenic Differentiation and Involvement of Transthyretin Gene in Adipogenesis in Cattle

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    <p>Adipose tissue plays central role in determining the gustatory quality of beef, but traditional Chinese beef cattle have low levels of fat content. We applied RNA-seq to study the molecular mechanisms underlying adipocyte differentiation in Qinchuan cattle. A total of 18,283 genes were found to be expressed in preadipocytes and mature adipocytes, respectively. 470 of which were significantly differentially expressed genes (DEGs) [false discovery rate (FDR) values < 0.05 and fold change ≥ 2]. In addition, 4534 alternative splicing (AS) events and 5153 AS events were detected in preadipocytes and adipocytes, respectively. We constructed a protein interaction network, which suggested that collagen plays an important role during bovine adipogenic differentiation. We characterized the function of the most down-regulated DEG (P < 0.001) among genes we have detected by qPCR, namely, the transthyretin (TTR) gene. Overexpression of TTR appears to promote the expression of the peroxisome proliferator activated receptor γ (PPARγ) (P < 0.05) and fatty acid binding Protein 4 (FABP4) (P < 0.05). Hence, TTR appears to be involved in the regulation of bovine adipogenic differentiation. Our study represents the comprehensive approach to explore bovine adipocyte differentiation using transcriptomic data and reports an involvement of TTR during bovine adipogenic differentiation. Our results provide novel insights into the molecular mechanisms underlying bovine adipogenic differentiation.</p

    Lipid Catabolism in Starved Yak Is Inhibited by Intravenous Infusion of β-Hydroxybutyrate

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    Lipid is the chief energy source for starved animals. &beta;-hydroxybutyrate (BHBA) is the main ketone body produced by lipid decomposition. In Chinese hamster ovary (CHO) cell experiment, it was found that BHBA could be used not only as an energy substance, but also as a ligand of GPR109A for regulating lipid metabolism. However, whether BHBA can regulate lipid metabolism of yaks, and its effective concentration and signal pathway are not clear. This study investigated the effects and mechanism of starvation and BHBA on the lipid metabolism of yak. Eighteen male Jiulong yaks were selected and then randomly divided into three groups: normal feeding group (NG), starvation group (SG), and starvation with BHBA infusion group (SBG). The yaks in the NG group were freely fed during the trial, while the yaks in the SG and SBG groups fasted; from 7th to 9th days of the experiment, the NG and SG were infused continuous with 0.9% normal saline and SBG was infused 1.7 mmol/L BHBA solution respectively. The blood samples were collected on the 0th, 1st, 3rd, 5th, 7th, and 9th day of experiment. The subcutaneous adipose tissue of all the yaks in this study were taken from live bodies after infusion. Serum glucose, lipid metabolites, hormone concentrations, and mRNA and protein expressions of key factors of lipid metabolism and signaling pathway in subcutaneous adipose tissue were measured. The results showed that, as compared with NG, starvation significantly reduced the body weight of yak in SG, and significantly increased the concentration of BHBA in serum and the mRNA expression of PKA and CREB1 in subcutaneous adipose tissue, while the mRNA expression of MEK, PKC, ERK1/2, the area of adipocytes, and the proportion of saturated fatty acid were decreased. Whereas, further increase of BHBA concentration through infusion promoted the mRNA expression of GPR109A receptor in the subcutaneous adipose tissue of SBG, inhibited the mRNA expression of AC and PKA, and decreased the phosphorylation protein abundance of CREB1, and significantly increased the diameter and area of adipocytes. These findings suggest that starvation led to enhanced lipid catabolism in yaks. An increasing BHBA concentration could increase the mRNA expression of GPR109A receptor in subcutaneous adipose tissue and inhibit the cAMP/PKA/CREB signaling pathway and lipid decomposition

    Effects of Land Transport Stress on Variations in Ruminal Microbe Diversity and Immune Functions in Different Breeds of Cattle

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    The intensity and specialization of beef cattle production make off-site fattening, and introduce new breeds need transportation to achieve the goals. The present study was aimed to investigate effects of land transport stress on hormones levels, microbial fermentation, microbial composition, immunity and correlation among them among Simmental Crossbred Cattle (SC), Native Yellow Cattle (NY), and Cattle Yak (CY). High-throughput sequencing was used to investigate the rumen microbial diversity. After transport stress cortisol (COR), adrenocorticotropic hormone (ACTH) and pro-inflammatory cytokines IL-6, TNF-&alpha;, and IL-1&beta; were increased (p &lt; 0.05) in all groups. Rumen lipopolysaccharide (LPS) was increased (p &lt; 0.05) in SC and CY groups. Total volatile fatty acids were increased (p &lt; 0.05) in all groups. The ruminal microbiota about OTUs, Chao1, and Shannon in SC and CY groups were higher than before transport. Prevotella1 in NY group was higher (p &lt; 0.05) than other groups before transport; after transport Firmicutes and Lactobacillus were increased (p &lt; 0.05) than other groups in CY. Lactobacillus was positively correlated with IL-6 and IL-4. Under transport stress, cattle may suffer from inflammatory response through modulating HPA axis and microbiota metabolite affects the secretion of hormone levels and immune function and breeds factor affect the performance of stress resistance

    miR-378a-3p promotes differentiation and inhibits proliferation of myoblasts by targeting HDAC4 in skeletal muscle development

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    <p>Muscle development, or myogenesis, is a highly regulated, complex process. A subset of microRNAs (miRNAs) have been identified as critical regulators of myogenesis. Recently, miR-378a was found to be involved in myogenesis, but the mechanism of how miR-378a regulates the proliferation and differentiation of myoblasts has not been determined. We found that miR-378a-3p expression in muscle was significantly higher than in other tissues, suggesting an important effect on muscle development. Overexpression of miR-378a-3p increased the expression of MyoD and MHC in C2C12 myoblasts both at the level of mRNA and protein, confirming that miR-378a-3p promoted muscle cell differentiation. The forced expression of miR-378a-3p promoted apoptosis of C2C12 cells as evidenced by CCK-8 assay and Annexin V-FITC/PI staining results. Through TargetScan, histone acetylation enzyme 4 (HDAC4) was identified as a potential target of miR-378a-3p. We confirmed targeting of HDAC4 by miR-378a-3p using a dual luciferase assay and western blotting. Our RNAi analysis results also showed that HDAC4 significantly promoted differentiation of C2C12 cells and inhibited cell survival through Bcl-2. Therefore, we conclude that miR-378a-3p regulates skeletal muscle growth and promotes the differentiation of myoblasts through the post-transcriptional down-regulation of HDAC4.</p
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