The classification of major depressive disorders (MDDs) is a challenging task in clinical practice, especially in low-resource scenarios where generalization is essential for effective adaptation. Recent progress in meta-training large language models (LLMs) via in-context learning (ICL) offers promise for robust adaptation to unseen tasks without parameter updates. However, existing methods rely on multitask fine-tuning and do not fully exploit the optimization advantages of model-agnostic meta learning (MAML) techniques, limiting their generalization. This study proposes prompt-MAML, a novel method for meta-training LLMs that enhances multimodal ICL for classifying MDD tasks. The method integrates audio-textual features through a transformer-based cross-modal alignment module and incorporates bi-level optimization to learn generalizable model parameters that adapt well to unseen tasks. Extensive experiments demonstrate that prompt-MAML outperforms strong baseline models by an average improvement in macro-F1 of +4% on seen domains, +3% on unseen domains, and +3% in few-shot settings, demonstrating robustness and effectiveness in data-scarce and cross-domain clinical scenarios. Additionally, exploration depth is shown to play a key role in task performance, and further analysis of task complexity, modality, and optimiser configurations highlights critical design considerations for meta-training LLMs.

The metaverse has gradually come into the public eye and has become a hotspot in cyberspace, but it still faces many technical difficulties to be solved. Blockchain is a key component of the metaverse, enhancing the development of the metaverse by connecting the real and virtual worlds seamlessly and solving some of the difficulties faced by the metaverse. Our paper comprehensively studies the development and application of blockchain technology in the metaverse. First, there is an introduction to blockchain and the metaverse, followed by a discussion of why blockchain should be integrated into the metaverse. Second, an overview of the main blockchain technologies is provided to evaluate blockchain’s role in the metaverse and the value is summarized. Third, the development of future integration of blockchain and metaverse is presented from the perspective of social life and technology. For social life, how to use blockchain in the metaverse to enhance and improve social life is discussed. Then, from the technical perspective, it discusses how blockchain shapes the metaverse. Finally, challenges associated with the integration of blockchain into metaverses are analyzed and some promising research directions and solutions are proposed.