The verbs ser and estar both mean ‘to be’. Ser is used with permanent things. Estar is used with temporary things. Adjectives can change their meaning according to whether ser or estar is used.

WAZOWNEK and his collaborators have studied the reduction of conjugated systems at the dropping mercury electrode 1. They have brought forward evidence to support the following mechanism : ...

The most consistent regional small-cap funds of the decade ...

It breaks my heart that I am unable to bid my last goodbye to my dear Low Ser. But I know Low Ser and she would have wanted me to put my patients as a priority and attend to their health first.