Typed states for the displayed outbound observations.
Source: paper_references, paper_reference_links, observed 2026-08-07T05:25:18.805614Z
Paper Citation Record · LEDGER
Congestion-Aware Path Selection for Load Balancing in AI Clusters
As of 19 August 2026, this Paper Citation Record lists 52 of 52 outbound references and 0 inbound Pith citation observations for arXiv:2506.08132.
A citation records a reference. It does not transfer a finding from one paper to another.
Coverage vector
One-hop event checks from named stored sources.
Source: scholarly_work_events, retraction_status_cache, observed 2026-08-19T06:32:44.657259+00:00
Pith citing papers itemized under the disclosed page cap.
Source: paper_references, paper_reference_links
A source-named dated measurement, never combined with another source.
Source: cited_works
Reference resolution
52 of 52 outbound references displayed
- verified exact0
- verified fuzzy8
- unresolved41
- parse uncertain0
- malformed identifier1
- metadata mismatch2
External citation measurements
No source-named external measurement is stored.
Outbound references
Observation dece2351-424c-43a3-9f77-ce3b1eaeddcf · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 1
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.862629Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation c8612fc5-9124-49cf-bfee-c714a3482e31 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 2
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.850552Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 84f77253-3271-4f34-9851-f766d358dee6 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 3
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.837573Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation b2b9cc92-a950-402b-8752-502051c360ee · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 4
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.825602Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 04256593-bc68-4a42-9c3e-149aaf1b3a15 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 5
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.812970Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 7f60a2b1-a65b-44d7-9f79-4e77ac5bfc8f · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 6
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.799800Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 06f8ef17-2b20-48a0-8f22-84cc8bcdc251 · outbound
This paper cites Charlie Hu, and Ramana Rao Kompella.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Charlie Hu, and Ramana Rao Kompella
Reference 7
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.786068Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation e0a98211-7747-4146-bcc8-b4a9af8d1e07 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 8
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.772393Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 1fb2d071-d71d-437f-946b-752b0b85f0a2 · outbound
This paper cites Brighten Godfrey, Yashar Ganjali, and Amin Firoozshahian.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Brighten Godfrey, Yashar Ganjali, and Amin Firoozshahian
Reference 9
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.758074Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 7ad6ffad-f331-4a79-a94b-e9f1a50cf1ac · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 10
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.743747Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation c0d1442d-14f7-416b-b6c2-50523b3e12fa · outbound
This paper cites Hamilton, Navendu Jain, Srikanth Kandula, Changhoon Kim, Parantap Lahiri, David A.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Hamilton, Navendu Jain, Srikanth Kandula, Changhoon Kim, Parantap Lahiri, David A
Reference 11
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.731213Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 34903799-12b6-4010-806f-dbb23e52db16 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 12
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.717130Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 243c0d75-d289-4270-9734-d92690bb5fb3 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 13
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.702007Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 16b1a5fd-083e-4b5a-abd3-a2a2271d57b4 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 14
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.687386Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 0757e4b7-76d7-4aba-9190-64df377afb21 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 15
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.673726Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation a69a93b7-2548-4aec-b397-c6bf4452a4d8 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 16
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.660325Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation f554a15d-b094-4f84-b9e8-483b708663ba · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 17
- Resolution
- metadata mismatch
- raw_fallback, observed 2026-08-07T05:25:19.281811Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation a8547488-291e-4029-9b84-c5f06c74e15f · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 18
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.644599Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation f89970ff-46a4-42f0-ba47-38365e983eae · outbound
This paper cites STrack: A Reliable Multipath Transport for AI/ML Clusters.
Congestion-Aware Path Selection for Load Balancing in AI Clusters STrack: A Reliable Multipath Transport for AI/ML Clusters
Reference 19
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.670200Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation b2ae4ce7-72a4-4532-86e8-88bf2a56b9d9 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 20
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.674744Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 75a4e055-4b19-42a7-9ee3-011290efe280 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 21
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.623271Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation a819ceea-6607-41a4-8867-61cbec9c0f56 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 22
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.597188Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation faabf692-0d81-4e50-9bce-e72f3626d45d · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 23
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.695463Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 12143e56-ea11-4d12-aa21-c4b3cc0f8ae9 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 24
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.584776Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation b2ce1c33-a1a9-4fb0-a717-312d63bba61c · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 25
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.572063Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 3a5ec29f-54d2-494a-b686-78dd02afd8cf · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 26
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.546538Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 81daa914-9959-42eb-a0bf-a6465609840a · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 27
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.533141Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 82ed0311-bc83-4ad0-bba5-a9acaebc739b · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 28
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.520207Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 968fee18-ecd4-4ad1-b4cc-2ee9e085be65 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 29
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.507850Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 845d6929-394c-43c4-9bcf-96aca3dc5590 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 30
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.495363Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 87602d42-bd4d-4dd0-84d3-b236e7fb9d11 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 31
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.483082Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 1145e6f7-5ee0-411f-a0da-93453fd16974 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 32
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.470624Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation ee4d046b-d8d4-41ab-b1e7-4ab2e12638d6 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 33
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.458546Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation c1412fb5-4aba-433a-bc56-ccae56c3e572 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 34
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.430600Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 77128e85-c621-4d83-8932-1b8e3a2c3265 · outbound
This paper cites 2024.Conges- tion Signaling (CSIG).
Congestion-Aware Path Selection for Load Balancing in AI Clusters 2024.Conges- tion Signaling (CSIG)
Reference 35
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.418355Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 08ce5295-9b7a-4209-aedb-624732380018 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 36
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.405542Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 7fc9560b-9105-46c3-9ccd-017dcd666032 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 37
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.378667Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation b27ad866-e3e9-4843-916b-db1938353cb3 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 38
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.365737Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation d11a77ff-1e7f-400b-b73d-2b5d1170444b · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 39
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.777674Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 90da6f88-2e9b-4f84-81cb-33d767c41a1f · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 40
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.337946Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation df075829-ff9b-48ab-bbfb-428f3855f2bc · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 41
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.390713Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 1607bedb-0caa-4908-823b-e6b36f0f13e0 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 42
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.312120Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 3f3838f5-9af2-40ea-bc06-0e9e7bfea06d · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 43
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.793718Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation e0856813-74c3-486c-9323-48e83074289c · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 44
- Resolution
- metadata mismatch
- raw_fallback, observed 2026-08-07T05:25:18.970854Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation e0e74a71-5549-4498-b90b-3a0dd6444d4f · outbound
This paper cites PyTorch FSDP: Experiences on Scaling Fully Sharded Data Parallel.
Congestion-Aware Path Selection for Load Balancing in AI Clusters PyTorch FSDP: Experiences on Scaling Fully Sharded Data Parallel
Reference 45
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.801426Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation 1ab3575c-1789-4ea6-b64e-7d8a92fb8ed6 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 46
- Resolution
- malformed identifier
- raw_fallback, observed 2026-08-07T05:25:19.297096Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation af05e48f-513c-4870-bb57-29311036eaf4 · outbound
This paper cites an unresolved cited work.
Congestion-Aware Path Selection for Load Balancing in AI Clusters Unresolved cited work
Reference 47
- Resolution
- unresolved
- raw_fallback, observed 2026-08-07T05:25:19.325035Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation b8401a6f-745e-4b18-8515-b2c6a266977b · outbound
This paper cites InProceedings of the 2015 ACM Conference on Special Interest Group on Data Communication(Lon- don, United Kingdom)(SIGCOMM ’15).
Congestion-Aware Path Selection for Load Balancing in AI Clusters InProceedings of the 2015 ACM Conference on Special Interest Group on Data Communication(Lon- don, United Kingdom)(SIGCOMM ’15)
Reference 2015
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.559330Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation f645740f-2bb3-4308-8223-a480a0098262 · outbound
This paper cites In14th USENIX Symposium on Networked Systems Design and Implementation (NSDI 17).
Congestion-Aware Path Selection for Load Balancing in AI Clusters In14th USENIX Symposium on Networked Systems Design and Implementation (NSDI 17)
Reference 2017
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.352777Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 52e9533b-5a12-43dc-afdf-a769cfd9debe · outbound
This paper cites InProceedings of the ACM Special Interest Group on Data Communication(Beijing, China)(SIGCOMM ’19).
Congestion-Aware Path Selection for Load Balancing in AI Clusters InProceedings of the ACM Special Interest Group on Data Communication(Beijing, China)(SIGCOMM ’19)
Reference 2019
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.610320Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Observation 460c7a64-9e41-4b09-82c7-61f4b5f88f61 · outbound
This paper cites PyTorch Distributed: Experiences on Accelerating Data Parallel Training.
Congestion-Aware Path Selection for Load Balancing in AI Clusters PyTorch Distributed: Experiences on Accelerating Data Parallel Training
Reference 2020
- Resolution
- unresolved
- no resolver link, observed 2026-08-07T05:25:18.678656Z
Source-reported events for the cited work
Unavailable: canonical work link unavailable.
Observation ee72ba67-6663-4c9d-a542-1edc0d370434 · outbound
This paper cites InProceedings of the ACM SIGCOMM 2024 Conference(Sydney, NSW, Australia) (ACM SIGCOMM ’24).
Congestion-Aware Path Selection for Load Balancing in AI Clusters InProceedings of the ACM SIGCOMM 2024 Conference(Sydney, NSW, Australia) (ACM SIGCOMM ’24)
Reference 2024
- Resolution
- verified fuzzy
- raw_fallback, observed 2026-08-07T05:25:19.444213Z
Source-reported events for the cited work
No event found in the named queried sources as of 2026-08-19T06:32:44.657259+00:00.
Pith citing papers
No inbound Pith citation observations are available.