SLSM : An Efficient Strategy for Lazy Schema Migration on Shared-Nothing Databases

By introducing intermediate states for metadata changes and ensuring that at most two versions of metadata exist in the cluster at the same time, shared-nothing databases are capable of making online, asynchronous schema changes. However, this method leads to delays in the deployment of new schemas since it requires waiting for massive data backfill. To shorten the service vacuum period before the new schema is available, this paper proposes a strategy named SLSM for zero-downtime schema migration on shared-nothing databases. Based on the lazy migration of stand-alone databases, SLSM keeps the old and new schemas with the same data distribution, reducing the node communication overhead of executing migration transactions for shared-nothing databases. Further, SLSM combines migration transactions with user transactions by extending the distributed execution plan to allow the data involved in migration transactions to directly serve user transactions, greatly reducing the waiting time of user transactions. Experiments demonstrate that our strategy can greatly reduce the latency of user transactions and improve the efficiency of data migration compared to existing schemes

Optimization of extraction process and antioxidant activity of total flavonoids from Aloe vera stir-fry products

Objective: To optimize the extraction process of total flavonoids from Aloe vera stir-fry products and investigate its antioxidant activity. Methods: Single factor test and response surface method were used to optimize the extraction process, The content of total flavonoids in Aloe vera raw and fried products from different areas was determined by UV spectrophotometry,The antioxidant activity was studied by DPPH·, ABTS+·, ·OH and FRAP methods, the correlation between total flavonoids yield and antioxidant activity was analyzed by Pearson correlation. Results: The optimal extraction conditions were as follows soaking time 3 h, ultrasonic time 15 min, ethanol volume fraction 60% and solid-liquid ratio 1∶10 （g/mL）. The content of total flavonoids in Aloe vera increased. The total flavonoids of Aloe vera raw and fried products from 8 producing areas had certain scavenging effect on four kinds of free radicals, and the concentration was positively correlated with that of Aloe vera, showing good antioxidant activity.Correlation analysis showed that antioxidant capacity was significantly correlated with total flavonoid yield. Conclusion: The optimized extraction process of total flavonoids from Aloe vera stir-fried products is reasonable and feasible, and has strong antioxidant activity

Research for Inertia Response and Primary Frequency Regulation Ability of Wind Turbine

[Introduction] Large-scale connection of wind power to the power grid poses great challenges to the stability (especially frequency stability) of grid operation.In order to solve the problem of inadequate frequency regulation capability caused by large-scale connection of wind power to the power grid and improve the frequency adaptability of wind power grid connection, wind turbines need to have frequency regulation function and response timeliness. [Method] This paper adopted a frequency regulation system scheme based on rotor kinetic energy and pitch angle reserve, which could provide active support for the power grid quickly and accurately during the power grid frequency change. Firstly, the main control algorithm was designed based on the theoretical analysis of inertia response and primary frequency regulation algorithm logic. Then, the functional verification was carried out on the co-simulation platform. Finally, the actual test was carried out in a project.[Result] The simulation and test results showed that the frequency regulation system scheme based on rotor kinetic energy and pitch angle reserve could cope with a variety of grid frequency changes and quickly provided active support. [Conclusion] The frequency regulation system scheme of wind turbines can perform a fast inertia response (with the response time less than 500 ms) and primary frequency regulation response (with the response time less than 5 s) under various frequency change conditions and provide active support for the power grid, which can help recover the grid frequency and effectively improve the frequency adaptability of wind turbines

The abundance of homoeologue transcripts is disrupted by hybridization and is partially restored by genome doubling in synthetic hexaploid wheat

Dataset S7. List of nonadditively expressed genes in F1 hybrids derived from AS2255 × AS60. (XLSX 72 kb

Identification of key genes affecting ventilator-induced diaphragmatic dysfunction in diabetic mice

BackgroundMechanical ventilation (MV) is often required in critically ill patients. However, prolonged mechanical ventilation can lead to Ventilator-induced diaphragmatic dysfunction (VIDD), resulting in difficulty in extubation after tracheal intubation, prolonged ICU stay, and increased mortality. At present, the incidence of diabetes is high in the world, and the prognosis of diabetic patients with mechanical ventilation is generally poor. Therefore, the role of diabetes in the development of VIDD needs to be discovered.MethodsMV modeling was performed on C57 mice and DB mice, and the control group was set up in each group. After 12 h of mechanical ventilation, the muscle strength of the diaphragm was measured, and the muscle fiber immunofluorescence staining was used to verify the successful establishment of the MV model. RNA sequencing (RNA-seq) method was used to detect mRNA expression levels of the diaphragms of each group, and then differential expressed gene analysis, Heatmap analysis, WGCNA analysis, Venn analysis, GO and KEGG enrichment analysis were performed. qRT-PCR was used to verify the expression of the selected mRNAs.ResultsOur results showed that, compared with C57 control mice, the muscle strength and muscle fiber cross-sectional area of mice after mechanical ventilation decreased, and DB mice showed more obvious in this respect. RNA-seq showed that these differential expressed (DE) mRNAs were mainly related to genes such as extracellular matrix, collagen, elastic fiber and Fbxo32. GO and KEGG enrichment analysis showed that the signaling pathways associated with diabetes were mainly as follows: extracellular matrix (ECM), protein digestion and absorption, PI3K-Akt signaling pathway, calcium signaling pathway, MAPK signaling pathway and AGE-RAGE signaling pathway in diabetic complications, etc. ECM has the closest relationship with VIDD in diabetic mice. The key genes determined by WGCNA and Venn analysis were validated by quantitative real-time polymerase chain reaction (qRT-PCR), which exhibited trends similar to those observed by RNA-seq.ConclusionVIDD can be aggravated in diabetic environment. This study provides new evidence for mRNA changes after mechanical ventilation in diabetic mice, suggesting that ECM and collagen may play an important role in the pathophysiological mechanism and progression of VIDD in diabetic mice, and provides some clues for the research, diagnosis, and treatment of VIDD in diabetic context

A Model for Transgenerational Imprinting Variation in Complex Traits

Despite the fact that genetic imprinting, i.e., differential expression of the same allele due to its different parental origins, plays a pivotal role in controlling complex traits or diseases, the origin, action and transmission mode of imprinted genes have still remained largely unexplored. We present a new strategy for studying these properties of genetic imprinting with a two-stage reciprocal F mating design, initiated with two contrasting inbred lines. This strategy maps quantitative trait loci that are imprinted (i.e., iQTLs) based on their segregation and transmission across different generations. By incorporating the allelic configuration of an iQTL genotype into a mixture model framework, this strategy provides a path to trace the parental origin of alleles from previous generations. The imprinting effects of iQTLs and their interactions with other traditionally defined genetic effects, expressed in different generations, are estimated and tested by implementing the EM algorithm. The strategy was used to map iQTLs responsible for survival time with four reciprocal F populations and test whether and how the detected iQTLs inherit their imprinting effects into the next generation. The new strategy will provide a tool for quantifying the role of imprinting effects in the creation and maintenance of phenotypic diversity and elucidating a comprehensive picture of the genetic architecture of complex traits and diseases

G Wireless Multimedia: Technologies and Practical Issues

This paper provides an overview of the emerging wireless communication standards, end-to-end wireless streaming systems, and relevant wireless multimedia technologies. It highlights some of the challenges in the deployment of 3G wireless multimedia services, using PacketVideo's solutions as an example