Improving retrospective data on recent household deaths: a multi-arm randomized trial in Guinea-Bissau.

Background: In countries with limited civil registration and vital statistics systems, assessing the impact of health crises requires precise retrospective mortality data. We tested whether calendar methods improve survey or census data on dates of recent household deaths registered in a Health and Demographic Surveillance System (HDSS).

Methods: Between April and June 2023, we randomized 578 households with HDSS-registered deaths in Guinea-Bissau to interviews by using (i) a standard questionnaire with close-ended questions about dates of deaths, or similar questionnaires supplemented with (ii) a physical calendar of local events printed on paper or (iii) a digital calendar implemented on tablets.

Remarkably efficient removal of toxic bromate from drinking water with a porphyrin-viologen covalent organic framework.

The presence of carcinogenic bromate (BrO ) in drinking water became a global concern and efforts towards its removal mainly focused on addressing the source. Herein, we rationally designed a porphyrin-based covalent organic framework () with a cationic surface to provide electrostatic interactions and a porphyrin core to induce hydrogen bonding interactions for the efficient removal of BrO from water. Through H-bonding and electrostatic interactions, exhibited an exceptional bromate removal efficiency (maximum adsorption capacity, : 203.