Gènes, environnement et neurodéveloppement: te cas de la schizophrénie [Schizophrenia: genes, environment and neurodevelopment].

Psychoses are complex diseases resulting from the interaction between genetic vulnerability factors and various environmental risk factors during the brain development and leading to the emergence of the clinical phenotype at the end of adolescence. Among the mechanisms involved, a redox imbalance plays an important role, inducing oxidative stress damaging to developing neurons. As a consequence, the excitatory/inhibitory balance in cortex and the pathways connecting brain areas are both impaired. Childhood and adolescence appear as critical periods of vulnerability for deleterious environmental insults. Antioxidants, applied during the environmental impacts, should allow preventing these impairments as well as their clinical consequences.

Simultaneous multielement extraction with the Mehlich-1 solution for Southern Brazilian soils determined by ICP-OES and the effects on the nutrients recommendations to crops

The amounts of macro (P, K, Ca and Mg) and micronutrients (Cu and Zn) extracted with the Mehlich-1 (M1) solution, by the 1.0 mol L-1 KCl (KCl) and with the 0.1 mol L-1 HCl (HCl) for representative soil types of the Rio Grande do Sul state (Brazil) were compared with those extracted with the Mehlich-1 solution determined with the inductively coupled plasma optical emission spectroscopy (ICP). The amounts of nutrients extracted by the different methods showed high correlation coefficients. On average, the Mehlich-1 solution extracted similar amounts of P, determined with colorimetric and ICP methods, and, K determined with emission and ICP. The amounts of Ca and Mg extracted with the Mehlich-1 solution, determined by ICP, were similar to those extracted with the KCl solution determined by the atomic absorption spectrophotometry. The amounts of Cu and Zn extracted with the Mehlich-1 solution, determined by the ICP, were higher than those extracted with the 0.1 mol L-1 HCl determined by the atomic absorption spectrophotometry. The results indicate that the Mehlich-1 solution and ICP can be used for simultaneous multielement extraction and determination for Southern Brazilian soils. However, a conversion factor for values interpretation is needed. The use of the conversion factor to determine the K availability index in soils is adequate and does not affect the K recommendations for crops in southern Brazilian soils.

Perceptions de la performance et comportements de agents publics suisses dans un environnement en constante évolution

Alors que les modèles et notions de performance généralement analysés dans les recherches sont presque toujours ceux du management et des cadres dirigeants, cet article propose de s'arrêter sur la vision des employés, en l'occurrence des agents publics suisses. Il présente, à la lumière des réformes entreprises dans l'administration publique en Suisse, d'une part la conception générale qu'ont les agents publics de la performance du service public, et d'autre part leur perception de l'évolution des performances organisationnelle, individuelle, ainsi que celle en lien avec les prestations fournies aux bénéficiaires. L'analyse de la performance perçue est effectuée à travers la mise en évidence de l'existence de plusieurs mondes de référence auxquels se rapportent les agents publics lorsqu'ils parlent de leur travail. Les résultats révèlent la prégnance du monde industriel, devançant le monde civique qui, lui-même, relègue les mondes domestique et marchand respectivement en troisième et quatrième position. Un intérêt particulier est également accordé aux différents comportements, découlant des réformes du service public, qu'adoptent les agents publics, et aux liens qui pourraient exister entre ces comportements et les différents mondes de référence. Un mariage entre deux mondes, potentiellement contradictoires, semble se dessiner dans l'esprit des agents publics. Il pourrait constituer une réponse à une forme de crise identitaire, mise en avant par de nombreux spécialistes, provoquée par des injonctions contradictoires auxquelles sont soumis actuellement les agents publics.

Water-soluble nutrients in aerial plant parts of peanut and white oat as affected by lime and gypsum application

Lime and gypsum influence nutrient availability and uptake, as well as the content of organic acids in the aerial plant parts. These changes, quantified by plant analysis of soluble nutrients, may potentiate the effect of soil amendment, ensuring the sustainability of the no-tillage system. In this sense the effect of lime and gypsum surface application on the content of water-soluble nutrients in peanut and oat residues was evaluated. The experiment was conducted on an Oxisol in Botucatu (SP) in the growing seasons 2004/2005 and 2005/2006. It was arranged in a randomized block design in split plots with four replications, where lime rates represented the plots and presence or absence of gypsum application the subplots. Peanut was grown in summer and white oat in the winter in the entire experimental area. Gypsum applied to peanut increased soluble Ca only in the first season, due to the short period between product application and determination of soluble nutrient contents in the plant extract. Liming of peanut and oat increased soluble Ca, Mg, K contents, did not alter Cu content and reduced Zn, Mn and Fe contents in both years of cultivation. Gypsum on the other hand reduced the electrical conductivity of peanut (2004/2005 and 2005/2006) and white oat (2004/2005).

Supply of nutrients and productive responses in dairy cows given diets based on restrictively fermented silage

Selostus: Ravintoaineiden saantiin ja maidontuotantoon vaikuttavat tekijät runsaalla säilörehuruokinnalla

The leaching of nutrients from ash- and PK-fertilised peat

Tiivistelmä: ravinteiden huuhtoutuminen tuhka- ja PK-lannoitetusta turpeesta

Nutrients in soil layers under no-tillage after successive pig slurry applications

Successive applications of pig slurry to soils under no-tillage can increase the nutrient levels in the uppermost soil layers and part of the nutrients may be transferred to deeper layers. The objective was to evaluate the distribution of nutrients in the profile of a soil after 19 pig slurry applications under no-tillage for 93 months. The experiment was conducted from May 2000 to January 2008 in an experimental area of the Federal University of Santa Maria, southern Brazil, on a Typic Hapludalf. The treatments consisted of pig slurry applications (0, 20, 40 and 80 m³ ha-1) and at the end of the experiment, soil samples were collected (layers 0-2, 2-4, 4-6, 6-8, 8-10, 10-12, 12-14, 14-16, 16-18, 18-20, 20-25, 25-30, 30-35, 35-40, 40-50 and 50-60 cm). The levels of mineral N, available P and K and total N, P and K were evaluated. The 19 pig slurry applications in 93 months promoted migration of total N and P down to 30 cm and available P and K to the deepest layer analyzed. At the end of the experiment, no increase was observed in mineral N content in the deeper layers, but increased levels of available P and K, showing a transfer of N, P and K to layers below the sampled. This evidences undesirable environmental and economic consequences of the use of pig slurry and reinforces the need for a more rational use, i.e., applications of lower manure doses, combined with mineral fertilizers.