SciDEX — Task: [Atlas] Research-front velocity meter for sub-fiel

Per-field velocity meter (z-scored hyps+papers+debates+OQs per week) with cold/warm/hot/red-hot bands and leaderboard.

Spec File

Effort: standard

Goal

Some sub-fields are accelerating (new hypothesis-per-week rate
spiking, new debates being spawned, new papers ingested), some
are dormant. Research funders, journalists, and senior PIs all
want to know "where is the action moving?" — but SciDEX surfaces
no per-sub-field velocity signal.

Build a Research-Front Velocity Meter: a per-sub-field
scalar (hypotheses per week + papers per week + debates per week,
weighted) plus a 12-week trend, plus a "hot fronts" leaderboard.
The meter drives the hero of whats-changed and gives every
intro page a "field heat" badge.

Acceptance Criteria

☐ New module scidex/atlas/research_front_velocity.py:

compute_velocity(field_slug: str, window_weeks: int = 4)
        -> dict

returns

{velocity_score, components:
        {new_hyps_per_week, new_papers_per_week,
        new_debates_per_week, new_open_questions_per_week},
        trend_12w: list[float], pct_rank_among_all_fields,
        velocity_band: 'cold'|'warm'|'hot'|'red-hot'}

.
- recompute_all_fields() walks the field registry and
writes to field_velocity_snapshots.

☐ New table field_velocity_snapshots with (field_slug,


      computed_at, velocity_score, components JSONB,
      trend_12w JSONB, pct_rank, velocity_band)

and an index
on (field_slug, computed_at DESC).

☐ Velocity formula (documented in module docstring):

velocity = 0.4  z(new_hyps) + 0.3  z(new_papers) +
      0.2  z(new_debates) + 0.1  z(new_open_questions)

where each component is z-scored against the field's
own trailing-12-week mean (so velocity measures
acceleration relative to baseline, not raw output —
avoids dominant fields permanently outranking niche
ones).

☐ Velocity bands: pct_rank ≤ 25 = cold, 25-50 = warm,

50-80 = hot, 80+ = red-hot.

☐ GET /research-fronts page shows leaderboard of all

registered fields sorted by velocity_score desc, with
band-color cards, sparkline of trend_12w, and a "drill in"
link to /intro/{field-slug}.

☐ Per-field velocity badge: every /intro/{field-slug}

page renders the band as a colored badge in the hero;
/field-trends/{field-slug} (q-time-field-time-series)
embeds the velocity meter at the top.

☐ Daily systemd timer scidex-field-velocity-daily.timer

recomputes the snapshot for every field; stale snapshots
(>48h) are flagged in senate_alerts.

☐ Pytest: synthetic 12-week activity for 3 fields with

known relative velocities; asserts band assignment
matches expectation; asserts the leaderboard ordering;
asserts trend_12w array length is exactly 12.