{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9fa2254f3b9b6040cbbfd0a5cf11d71c9b1ecf875f737789104834da4cdbfd52","created":"2026-10-03T07:17:57Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"ee3240b9d721fce7e7054a562949fde26f9ee45924e52e74130bb23c26720630","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"bio.collective-behavior.collective-gradient-sensing","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Single cells can be poor at sensing a weak chemical gradient, but clusters of cells sometimes follow gradients better than any single member. How much a group can gain, and what limits it, is unsettled.","posed_since":"","precise":"For a cluster of $N$ cells of size a, coupled by gap junctions or mechanical contacts, in a shallow gradient g = |grad c|/c, find the minimum error in estimated gradient direction as a function of $N$, intercellular communication noise and cluster geometry. Answer: the scaling of the error with N, including the crossover from N^-1/2 averaging to saturation set by communication noise, compared with experiments on cell clusters.","problem_ref":null,"references":"","settled_by":"Measurements of chemotactic accuracy versus cluster size with controlled coupling strength, compared with the predicted crossover.","status_note":"Theory since 2016 predicts saturation at large N from communication noise; quantitative experimental tests remain few.","title":"Physical limits of gradient sensing by cell collectives","topic_ref":"169c237bb7dec2b851fb7b715df607d983a88bff09590a878223e10c99e9ed50"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"aa0b8774704ba75ceaf93f5d9fefc9f1fade866637a142e72804df6a11674d83","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f74d57eed79ecb8f1fa9d46025914fdad3c7dbfe605695055d66bea4cac577a1","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"pggZ_Q1Ri-c3lo8gVZjf_PEeTaNcR3BXtkE_R-ElPb5zr8Q7sCgd7VhIDTh9bxwH6HhokwLUJWeCicoprCkIDg"},"schema":"pubphys.envelope/1"},"record_hash":"aa0b8774704ba75ceaf93f5d9fefc9f1fade866637a142e72804df6a11674d83","leaf_index":744}