École Polytechnique Fédérale de Lausanne

About: École Polytechnique Fédérale de Lausanne is a facility organization based out in Lausanne, Switzerland. It is known for research contribution in the topics: Population & Catalysis. The organization has 44041 authors who have published 98296 publications receiving 4372092 citations. The organization is also known as: EPFL & ETHL.

Processes governing phosphorus availability in temperate soils

Abstract: Phosphorus losses from agricultural soil to water bodies are mainly related to the excessive accumulation of available P in soil as a result of long-term inputs of fertilizer P. Since P is a nonrenewable resource, there is a need to develop agricultural systems based on maximum P use efficiency with minimal adverse environmental impacts. This requires detailed understanding of the processes that govern the availability of P in soil, and this paper reviews recent advances in this field. The first part of the review is dedicated to the understanding of processes governing inorganic P release from the solid phase to the soil solution and its measurement using two dynamic approaches: isotope exchange kinetics and desorption of inorganic P with an infinite sink. The second part deals with biologically driven processes. Improved understanding of the abiotic and biotic processes involved in P cycling and availability will be useful in the development of effective strategies to reduce P losses from agricultural soils, which will include matching crop needs with soil P release and the development of appropriate remediation techniques to reduce P availability in high P status soils.

Effect of pH, inorganic ions, organic matter and H2O2 on E. coli K12 photocatalytic inactivation by TiO2: Implications in solar water disinfection

Abstract: The effect of different chemical parameters on photocatalytic inactivation of E. coli K12 is discussed. Illumination was produced by a solar lamp and suspended TiO2 P-25 Degussa was used as catalyst. Modifications of initial pH between 4.0 and 9.0 do not affect the inactivation rate in the absence or presence of the catalyst. Addition of H2O2 affects positively the E. coli inactivation rate of both photolytic (only light) and photocatalytic (light Plus TiO2) disinfection processes. Addition of some inorganic ions (0.2 mmol/l) like HCO3-, HPO42-, Cl-. NO3- and SO42- to the suspension affects the sensitivity of bacteria to sunlight in the presence and in absence of TiO2. Addition of HCO3- and HPO42- resulted in a meaningful decrease in photocatalytic bactericidal effect while it was noted a weak influence of Cl-, SO42- and NO3-. The effect of counter ion (Na+ and K-) is not negligible and can modify the photocatalytic process as the anions. Bacteria inactivation was affected even at low concentrations (0.2 mmol/l) of SO42- and HCO3- but the same concentration does not affect the resorcinol photodegradation, suggesting that disinfection is more sensitive to the presence of natural anions than photocatalytic degradation of organic compounds. The presence of organic substances naturally present in water like dihydroxybenzenes isomers shows a negative effect on photocatalytic disinfection. The effect of a mixture of chemical substances on photocatalytic disinfection was also studied by adding to the bacterial suspension nutrient broth, phosphate buffer and tap water. (C) 2004 Elsevier B.V. All rights reserved.

Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation

Abstract: The Consultation reached a general consensus on several important issues. First, that universal salt iodisation‡ (USI) remains the key strategy to eliminate iodine deficiency disorders. Second, that where USI has been effective for at least 2 years, with salt adequately iodised and consumed by more than 90% of the population 1 , it can be reasonably expected that the iodine needs of women of child-bearing age and pregnant and lactating women are covered by their diet, and that the iodine stored in the thyroid gland is sufficient to ensure adequate hormone synthesis and secretion. Third, that iodised salt may not provide enough iodine to meet a child’s needs during complementary feeding, especially if the mother is only marginally iodine sufficient, unless complementary foods are fortified with iodine. It may be necessary therefore to give additional iodine to makesure that requirements are met until such time as the child starts to eat the normal family food. Finally, there was consensus that monitoring of both iodised salt quality and iodine nutrition are important to ensure that an optimal state of iodine nutrition is reached and then sustained. The Consultation made several specific recommendations concerning requirements, indicators and strategies to control iodine deficiency disorders in pregnant and lactating women, and in children less than 2-years-old.