The phrase "are now characterized" is correct and usable in written English.
It can be used to describe the current state or features of something, often in a formal or academic context.
Example: "The species are now characterized by their unique adaptations to the environment."
Alternatives: "are currently defined" or "are presently described".
In 1595 Percy settled upon Harriot an estate in Durham, England, and soon provided him with a house near London, which he also used as a scientific laboratory to pursue original research in astronomy, meteorology, optics, and what are now characterized as pure and applied mathematics.
For a homogeneous and regular cellular network, inteferers are now characterized by the interfering BS density ρBS.
Working conditions are now characterized by a high work load, an effort-reward imbalance, less job security, and the continual need to update skills [1].
B 106 (2002 87055) are now characterized by RRDE experiments to determine the values of the apparent number of electron transferred (n) and the percentage of peroxide (%H2O2) released during the oxygen reduction reaction (ORR) in H2SO4 at pH 1.
Numerous interactions between constitutive nuclear proteins and viral factors are now characterized but less is known concerning their functional significance and their connection with viral-induced modifications of nuclear ultrastructure.
Specifically, since the advent of cART, HIV-infected individuals are now characterized by low viral loads yet high levels of neurotoxic Tat protein.
At daily briefings in recent days, senior American officials are now characterizing the Yemeni cooperation as merely "professional".
So, reporters who are now characterizing Pope Francis as "liberal" then seem perplexed that he has not yet overturned Church teachings on moral issues like abortion.
We are now characterizing some of these sequences experimentally.
Deeper troughs (geosynclines) lay seaward of the continental masses, and their sedimentary record is now characterized by mountains.
The whole business is now characterized by ironies: A government that has one branch prosecuting American sweatshops while another one encourages establishing them abroad.
