Experimental study on fracture plugging effect of irregular-shaped lost circulation materials

Using micro-visualization experimental device for the formation of fracture plugging zone, the plugging behavior of irregular-shaped lost circulation materials (LCMs) with different types and concentrations in fractures was experimentally analyzed. The results show that the sealing time decreases significantly with the increase of material concentration. When the concentration is 20%, the sealing times of materials LCM-1∼LCM-5 are 6s, 7s, 5s, 6s, 4s, respectively. The formation of fracture plugging zone includes two stages, and the main factors affecting the formation of fracture plugging zone are flatness, roundness, convexity and concentrations. Flatness affects the retention stage of LCMs through the matching degree between particle size and fracture width. Convexity and roundness affect the retention stage by increasing the friction coefficient between particles. The high-efficiency retention ability of irregular LCMs is characterized by strong matching to fracture width, and strong friction and sliding resistance between particles. It is recommended that the optimized geometric parameters of high-efficiency retention materials should meet the requirements of “low flatness, low roundness and low convexity” (flatness \u3c0.6, roundness \u3c0.6 and convexity \u3c0.8), which can improve the plugging effect significantly

Infrared echo and late-stage rebrightening of nuclear transient PS1-10adi: exploring Torus by tidal disruption event in active galactic nuclei

Tidal disruption events (TDEs) in active galactic nuclei (AGNs) have been overlooked for a long time but tentatively been investigated recently. We report the discovery of a long-lasting luminous mid-infrared (mid-IR) flare in PS1-10adi, which is a newly-identified highly energetic transient event occurred in AGN. The IR luminosity of PS1-10adi, as well as other analogous events, are at least one order of magnitude higher than all known supernova, but can be well interpreted as the dust echoes of TDEs, whose ultra-high IR energy is reprocessed from the dusty torus around the black hole. The torus dust is sublimating during the early stage of the outburst and probably lead to the observed rapid emergence of Fe II lines. Moreover, the UV-optical rebrightening and contemporaneous X-ray onset after $\sim1500$ rest-frame days since the optical peak is also an intriguing feature of PS1-10adi, which could be attributed to the interaction between the high-velocity outflow and torus. We suggest that the luminous IR echo is a very typical phenomenon of TDEs in AGNs and may provide us an ideal opportunity to explore the torus properties.Comment: Accepted by ApJ, 1 table, 8 figure

Identification of SNPs in MITF associated with beak color of duck

Introduction: Beak color—a pigment-related trait—is an important feature of duck breeds. Recently, little research has addressed genetic mechanism of the beak colors in poultry, whereas the process and the regulation factors of melanin deposition have been well described.Methods: To investigate the genetic mechanism of beak colors, we conducted an integrated analysis of genomic selection signatures to identify a candidate site associated with beak color. For this, we used black-billed (Yiyang I meat duck synthetic line H1, H2, H3&HF) and yellow-billed ducks (Cherry Valley ducks and white feather Putian black duck). Quantitative real-time PCR and genotyping approaches were used to verify the function of the candidate site.Results: We identified 3,895 windows containing 509 genes. After GO and KEGG enrichment analysis, nine genes were selected. Ultimately, MITF was selected by comparing the genomic differentiation (FST). After loci information selection, 41 extreme significantly different loci were selected, which are all located in intron regions of MITF and are in almost complete linkage disequilibrium. Subsequently, the site ASM874695v1:10:g.17814522T > A in MITF was selected as the marker site. Furthermore, we found that MITF expression is significantly higher in black-beaked ducks than in yellow-beaked ducks of the F2 generation (p < 0.01). After genotyping, most yellow-billed individuals are found with homozygous variant; at the same time, there are no birds with homozygous variant in black-billed populations, while the birds with homozygous and heterozygous variant share the same proportion.Conclusion:MITF plays a very critical role in the melanogenesis and melanin deposition of duck beaks, which can effectively affect the beak color. The MITF site, ASM874695v1:10:g.17814522T > A could be selected as a marker site for the duck beak color phenotype

Long-Term Effects of Tai Chi Intervention on Sleep and Mental Health of Female Individuals With Dependence on Amphetamine-Type Stimulants

Previous studies provide evidence that Tai Chi (TC) can reduce the symptoms of sleep problems and be of benefit for the rehabilitation of substance abusers. In this study, we investigated if TC practice can improve sleep quality and mood of females who are dependent on amphetamine-type stimulant (ATS). Eighty subjects were randomly assigned to TC intervention and standard care (SC) for 6 months. We applied analysis of variance on repeated-measure with the year of drug dependence as the covariate to test the changes of the self-rated Pittsburg Sleep Quality Index (PSQI), Self-Rating Depression Scale (SDS), as well as fitness after 3 and 6 months. Relapse investigation was conducted by checking the database of China's National Surveillance System on Drug Abuse and that of the Shanghai Drug Control Committee's illicit drug dependents. Our investigation focused on the relapse of participants who had undergone and completed treatment in the Shanghai Mandatory Detoxification and Rehabilitation Center in 2015. The result showed that the PSQI scores of sleep duration [F(2, 92) = 9.86], need for sleep medications [F(2, 92) = 36.44] and daytime dysfunction [F(2, 92) = 5.15] were found to have a significant difference by time × group interaction after 6 months. SDS showed no significant difference between the two groups; however, the score of SDS in TC decreased after 6-month intervention, and no changes were observed in SC. Pulse rate had significantly decreased in the TC group compared with the SC group after 6 months. 9.5% (4) ATS dependents in TC and 26.3% (10) ATS dependents in SC were found to have relapsed. Our result suggested that TC had positive effects on sleep quality, depression and fitness. Long-term study demonstrated that TC may be a cheap and potential supplementary treatment for ATS-dependent individuals. TC may also be considered as an alternative exercise to escalate abstinence for ATS-dependent females.Clinical trial registration: ChiCTR-IPR-14005343 chictr. org.c