Can a judge examine witnesses to elicit or clarify testimony?

"A trial judge may examine witnesses to elicit or clarify testimony [citations]. Indeed, 'it is the right and duty of a judge to conduct a trial in such a manner that the truth will be established in accordance with the rules of evidence.' [Citation.] The trial judge, however, must not become an advocate for either party or under the guide of examining witnesses comment on the evidence or cast aspersions or ridicule on a witness. [Citations.]" (People v. Rigney (1961) 55 Cal.2d 236, 241.)