128 research outputs found

    Subgenomic Stability of Progenitor Genomes During Repeated Allotetraploid Origins of the Same Grass Brachypodium hybridum

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    Both homeologous exchanges and homeologous expression bias are generally found in most allopolyploid species. Whether homeologous exchanges and homeologous expression bias differ between repeated allopolyploid speciation events from the same progenitor species remains unknown. Here, we detected a third independent and recent allotetraploid origin for the model grass Brachypodium hybridum. Our homeologous exchange with replacement analyses indicated the absence of significant homeologous exchanges in any of the three types of wild allotetraploids, supporting the integrity of their progenitor subgenomes and the immediate creation of the amphidiploids. Further homeologous expression bias tests did not uncover significant subgenomic dominance in different tissues and conditions of the allotetraploids. This suggests a balanced expression of homeologs under similar or dissimilar ecological conditions in their natural habitats. We observed that the density of transposons around genes was not associated with the initial establishment of subgenome dominance; rather, this feature is inherited from the progenitor genome. We found that drought response genes were highly induced in the two subgenomes, likely contributing to the local adaptation of this species to arid habitats in the third allotetraploid event. These findings provide evidence for the consistency of subgenomic stability of parental genomes across multiple allopolyploidization events that led to the same species at different periods. Our study emphasizes the importance of selecting closely related progenitor species genomes to accurately assess homeologous exchange with replacement in allopolyploids, thereby avoiding the detection of false homeologous exchanges when using less related progenitor species genomes

    AceGPT, Localizing Large Language Models in Arabic

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    This paper explores the imperative need and methodology for developing a localized Large Language Model (LLM) tailored for Arabic, a language with unique cultural characteristics that are not adequately addressed by current mainstream models like ChatGPT. Key concerns additionally arise when considering cultural sensitivity and local values. To this end, the paper outlines a packaged solution, including further pre-training with Arabic texts, supervised fine-tuning (SFT) using native Arabic instructions and GPT-4 responses in Arabic, and reinforcement learning with AI feedback (RLAIF) using a reward model that is sensitive to local culture and values. The objective is to train culturally aware and value-aligned Arabic LLMs that can serve the diverse application-specific needs of Arabic-speaking communities. Extensive evaluations demonstrated that the resulting LLM called `AceGPT' is the SOTA open Arabic LLM in various benchmarks, including instruction-following benchmark (i.e., Arabic Vicuna-80 and Arabic AlpacaEval), knowledge benchmark (i.e., Arabic MMLU and EXAMs), as well as the newly-proposed Arabic cultural \& value alignment benchmark. Notably, AceGPT outperforms ChatGPT in the popular Vicuna-80 benchmark when evaluated with GPT-4, despite the benchmark's limited scale. % Natural Language Understanding (NLU) benchmark (i.e., ALUE) Codes, data, and models are in https://github.com/FreedomIntelligence/AceGPT.Comment: https://github.com/FreedomIntelligence/AceGP

    Zanthoxylum alkylamides activate phosphorylated AMPK and ameliorate glycolipid metabolism in the streptozotocin-induced diabetic rats

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    This study aimed to evaluate the effects of Zanthoxylum alkylamides on the glycolipid metabolism of rats with streptozotocin (STZ)-induced diabetes. Diabetic rats were given daily oral treatments of 2, 4, or 8 mg/kg bw alkylamides for 28 days. Alkylamides significantly decreased fasting blood glucose and fructosamine content, as well as relieved organ enlargement caused by diabetes. The serum and liver triglyceride, malondialdehyde, and free fatty-acid contents of rats with STZ-induced diabetes were significantly reduced. Total cholesterol in the liver also significantly decreased. Quantitative polymerase chain reaction (Q-PCR) and Western blot detected insignificantly increased (P > 0.05) mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK) in the skeletal muscle of diabetic rats. However, AMPK and p-AMPK (Thr172) protein expression levels significantly increased. The mRNA and protein expression levels of silencing information regulator 1 significantly increased. The mRNA expression levels of acetyl-CoA-carboxylase (ACC) and protein p-ACC (Ser79) also increased. The mRNA and protein expression levels of glucose transporter type 4 (GLUT4) were significantly upregulated in the skeletal muscle cell membranes of diabetic rats. Results indicated that alkylamides activated the AMPK-signaling pathway. Thus, inhibiting ACC activity reduced fatty-acid synthesis. The rapid translocation of GLUT4 mediated increased glucose transport rate and reduced blood glucose. Therefore, alkylamides can ameliorate glucose and lipid metabolism disorders in diabetic rats by activating the AMPK pathway

    A Clustering-based Framework for Improving the Performance of JPEG Quantization Step Estimation

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    A new impulsive synchronization criterion for T–S fuzzy model and its applications

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    This paper focuses on the problem of impulsive synchronization of T–S fuzzy systems. A new synchronization criterion is derived for T–S fuzzy systems by utilizing the concept of average impulsive interval. The proposed impulsive control scheme has a simple control structure, and is theoretically and numerically proved to be less conservative than some existing results. The method is also illustrated by applying to Lorenz system, Rössler’s system as well as permanent magnet synchronous motors system
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