Optimization of the proportions of four wastewaters in a blend for the cultivation of microalgae using a mixture design.

A 2nd degree mixture design was used to determine the optimal blend prepared from four wastewater streams to produce microalgae-based biomass. The streams consisted of a liquid digestate from an anaerobic digestion process, a landfill leachate, a septic-system sludge treatment plant liquid, and a wastewater treatment plant effluent. The mixture regression analysis indicated that blends with higher proportions of treated effluent and digestate improved cells growth, while the use of leachate was detrimental to the growth. The global solution of the mixture optimization predicted a maximum value of biomass productivity of 22.76 mg L-1 d-1, in a blend consisting of 19% treated effluent, 21% digestate, and 60% water. Proportions of leachate higher than 13.33% were detrimental to the growth. The concentration of ammonia-N in the blends ranged from 0.39 to 150 mg L-1 d-1, and its toxicity effect on the cells diminished with increasing amounts of organic carbon in the cultivation medium.

[Program for selective dissemination of information in support of priority health problems. II]. / Programa de diseminación selectiva de información en apoyo a problemas prioritarios de salud II.

México's National Health Information and Documentation Center (CENIDS), planned and designed a Selective Dissemination of Information Program in support of Priority Health Problems (DSI-APS). After one year of the implementation phase of this Program, an evaluation survey was conducted in order to measure its impact. Two questionnaires were sent to the institutional managers (C-I) and to the end-users (C-II). A total of 54 questionnaires (CI and CII) were sent via air mail to both the Health and the Education Sectors. Fifty (92.59%) responses were obtained from CI and 242 from CII. (CII could be reproduced as many times as needed). The results indicated the topics of more demand by the institutions and by the users. Eighty one per cent of the end-users scored over eight (scale 1-10) their degree of satisfaction when using the topics. Seventy two per cent of the institutions reported being unable to pay for this service; however, 93% of the end-users state that the Program should continue. It was detected that the topics represent an important support to "research" and "delivery of health care" activities. Finally, it was recommended to carry out specific studies so as to reformulate search strategies; satisfy selective needs, considering the impact obtained; and optimize existent resources.