English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

This paper outlines the roadmap towards the redefinition of the second, whichwas recently updated by the CCTF Task Force created by the CCTF in 2020. Themain achievements and the open challenges related to the status of the opticalfrequency standards, their contribution to time scales and UTC, the possibilityof their comparison and the knowledge of the Earth's gravitational potential atthe necessary level of uncertainty are discussed. In addition, the mandatorycriteria to be achieved before redefinition and their current fulfilment level,together with the redefinition options based on a single or on a set oftransitions are described.

Roadmap towards the redefinition of the second