The city of Rio de Janeiro has post-trained and released a massive language model named Rio 3.5 Open, with 397 billion parameters. It is built upon a Qwen base model—referred to as Qwen 7/2—and integrates SwiGLU activation and Rotary positional embeddings. The model is openly accessible, marking a rare public-sector contribution of a large-scale open LLM.
The viral study tested medical AI products UpToDate and OpenEvidence—not underlying models—on benchmarks like MedQA and HealthBench, finding them worse than frontier general-purpose models. The author argues this does not prove domain-specific models are inherently inferior; their own comprehensive benchmark shows fine-tuning a frontier model for medicine yields a noticeable boost. Current domain-specific models often lag because they are built on older or weaker open-source base models, not because specialization fails. For example, Baichuan-M4 is cited as a medical-specific model that claims to outperform frontier models. The main takeaway is that adapting strong frontier models into medical tools quickly would produce superior domain-specific systems, but open-source base model progress and adaptation speed remain challenges.
Trajectory Labs announced they have achieved frontier model performance using an open model that was post-trained in under 24 hours. The training infrastructure was powered by Together Compute and NVIDIA. No specific model name, benchmark metrics, or dataset details were provided in the social media post. The announcement highlights the potential of combining open models with efficient training infrastructure.
On the NVIDIA AI Podcast, Mistral AI CTO and co-founder Timothée Lacroix discussed the company's open-model philosophy, its Forge customization framework, and the collaboration with NVIDIA through the Nemotron Coalition. The conversation addresses bringing open models to enterprise environments. Lacroix elaborated on Mistral's approach to openness and model adaptation. The Nemotron Coalition is a partnership aimed at advancing AI capabilities.
A weekly roundup of top AI papers on Hugging Face highlights a study on scaling parameter-efficient fine-tuning (PEFT) to millions of personalized models with trillions of parameters. The research explores how to efficiently adapt large models for individual users without full fine-tuning. This approach could enable highly personalized AI systems at scale. The paper is part of a broader collection of notable AI publications from June 1-7.
A user on X expressed that it is empowering to post-train a Hugging Face model and push it back to the Hub for sharing. The Hugging Face official account retweeted this comment, underscoring user satisfaction with the platform’s workflow. The interaction highlights how seamless fine-tuning and redistribution have become through Hugging Face’s ecosystem.