Issue

25 October 2026

2 min read · 1 Short

AI & Tech: RFD4-Proteina, plain RAG vs agent memory, where "wait" comes from, six-week forecasts. Then lost in the middle, RL sharpens, protein diffusion.

AI & Tech

RFD4-Proteina, plain RAG, "wait", six-week forecasts

AI & Tech: RFD4-Proteina, plain RAG vs agent memory, where "wait" comes from, six-week forecasts. Then lost in the middle, RL sharpens, protein diffusion.

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4 News

AI · Protein design

RFD4-Proteina: protein design that thinks longer (preprint)

The Institute for Protein Design and NVIDIA released RFD4-Proteina, an open model that can spend more computing on hard design problems. It succeeds five to ten times more often, and runs five to ten times faster. With Manchester, it designed enzymes for making an HIV prevention drug. It is still a preprint.

RFD4-Proteina: protein design that thinks longer (preprint)
Image: University of Manchester

AI · Agents

Plain RAG beats complex agent memory

Do AI agents need complex memory? Researchers in China tested plain retrieval and reranking over the raw conversation history. It ranked first in six of seven benchmark settings, beating the strongest agentic memory system by up to 5.5 points, because it keeps more of the evidence.

Plain RAG beats complex agent memory
Figure: Bao et al., arXiv 2610.30755 · CC BY 4.0

AI · Reasoning

Reasoning models inherit their 'wait'

Reasoning models often write 'wait' before rechecking a step, usually credited to reinforcement learning. A Hong Kong team traced the word through open models' training. Reinforcement learning from scratch almost never coins it; it arrives with training data. So counting 'wait' is no proof of learned reasoning.

Reasoning models inherit their 'wait'
Figure: Kou et al., arXiv 2610.30882 · CC BY 4.0

AI · Weather

Machine learning doubles six-week forecasts

Forecasts two to six weeks ahead are notoriously hard. A team including MIT and Microsoft built a machine-learning layer that learns a forecast model's past errors and corrects them. In a European competition, it doubled the model's predictive power and beat climate averages. Published in Nature.

Machine learning doubles six-week forecasts
Figure: Nature briefing, Guan et al. 2026 · CC BY-NC-ND 4.0

3 Ideas

Idea · Language models

Lost in the middle

Lost in the middle. Language models use information best at the start or end of their context, and worst in the middle. In a 2023 test with twenty documents, accuracy dropped when the right one sat in the middle. That is one reason reranking, which puts the best evidence first, still matters.

Liu et al. 2023 · arXiv:2307.03172

Lost in the middle
Diagram: own drawing · Liu et al. 2023

Idea · Training

RL draws out, it does not create

Reinforcement learning with verifiable rewards makes a model likelier to find a correct reasoning path on its first try. But a 2025 study found those paths were already in the base model: given many attempts, it solves as many problems, or more. Training sharpens what is there, like today's 'wait'.

Yue et al. 2025 · arXiv:2504.13837

RL draws out, it does not create
Diagram: own drawing · Yue et al. 2025

Idea · Protein design

Designing proteins by removing noise

Diffusion models start from random noise and remove it step by step, the way image generators sharpen a picture. RFdiffusion applied this to protein backbones: start from scrambled coordinates, then denoise toward a structure that meets a goal, such as binding a target. It is an ancestor of today's RFD4-Proteina.

Watson et al. 2023 · Nature

Designing proteins by removing noise
Diagram: own drawing · Watson et al. 2023

Credits

  • Image: University of Manchester
  • Figure: Bao et al., arXiv 2610.30755 · CC BY 4.0
  • Figure: Kou et al., arXiv 2610.30882 · CC BY 4.0
  • Figure: Nature briefing, Guan et al. 2026 · CC BY-NC-ND 4.0
  • Diagram: own drawing · Liu et al. 2023
  • Diagram: own drawing · Yue et al. 2025
  • Diagram: own drawing · Watson et al. 2023

Voice: synthetic (neural text-to-speech).

Scripts written from the linked sources.

4 News 3 IdeasNews and IdeasAI and techartificial intelligenceprotein designRFD4-ProteinaInstitute for Protein DesignNVIDIAenzyme designRAGretrieval augmented generationagent memoryrerankingreasoning modelsreinforcement learningLLMsubseasonal forecastingweather forecastlost in the middleRFdiffusiondiffusion modelsmachine learning

Question of the day

In how many of seven benchmark settings did plain retrieval with reranking rank first?

Three

Six

All seven

The ballot is in the email. Each choice there is counted once.

Also on 25 Oct 2026: Biology & Nature Mind & Society Physics & Engineering

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