Evaluation of the impact of various agricultural practices on nitrate leaching under the root zone of potato and sugar beet using the STICS soil–crop model

The quaternary aquifer of Vitoria-Gasteiz (Basque Country, Northern Spain) is characterised by a shallow water table mainly fed by drainage water, and thus constitutes a vulnerable zone in regards to nitrate pollution. Field studies were performed with a potato crop in 1993 and a sugar beet crop in 2002 to evaluate their impact on nitrate leaching. The overall predictive quality of the STICS soil–crop model was first evaluated using field data and then the model was used to analyze dynamically the impacts of different crop management practices on nitrate leaching. The model was evaluated (i) on soil nitrate concentrations at different depths and (ii) on crop yields. The simulated values proved to be in satisfactory agreement with measured values. Nitrate leaching was more pronounced with the potato crop thanwith the sugar beet experiment due to i) greater precipitation, ii) lower N uptake of the potato crop due to shallow root depth, and iii) a shorter period of growth. The potato experiment showed that excessive irrigation could significantly increase nitrate leaching by increasing both drainage and nitrate concentrations. The different levels of N-fertilization examined in the sugar beet study had no notable effects on nitrate leaching due to its high N uptake capacity. Complementary virtual experiments were carried out using the STICS model. Our study confirmed that in vulnerable zones agricultural practices must be adjusted, that is to say: 1) N-fertilizer should not be applied in autumn before winter crops; 2) crops with low N uptake capacity (e.g. potatoes) should be avoided or should be preceded and followed by nitrogen catch crops or cover crops; 3) the nitrate concentration of irrigation water should be taken into account in calculation of the N-fertilization rate, and 4) Nfertilization must be precisely adjusted in particular for potato crops

Social Mix Policies in Paris: Discourses, Policies and Social Effects

International audienceSince the 1980s, the issue of social mix has become a public policy category in France. Enshrined in legislation, yet remaining controversial, it represents a major premise on which housing policies have been reconfigured. The concept of social mix is essentially based on who lives where, but it is also evoked in the context of urban renewal schemes for social housing estates, as well as in relation to new-build developments. A study of the bases of social mix policies conducted in Paris since 2001 in the context of the embourgeoisement of the capital shows the fundamental role of social housing stock. The City Council has become involved in policy decisions about both the location and the allocation of social housing. Particular attention has been paid to the middle classes in the name of the principle of 'balancing the population'. In order to measure the effects of the policy, this article relies on an analysis of two City of Paris schemes that have the stated intent of creating social mix. One of these schemes consists of redeveloping a working-class neighbourhood, Goutte d'Or, while the other involves the new acquisition of social housing in various more affluent neighbourhoods in the capital. This comparative study of the population shows that, whether in a neighbourhood poised for gentrification or in a more affluent neighbourhood, this policy has major effects on forms of local social cohesion, setting in motion individual trajectories and reshaping social and/or ethnic identities

Does intercropping winter wheat (Triticum aestivum) with red fescue (Festuca rubra) as a cover crop improve agronomic and environmental performance? A modeling approach

[email protected] audienceThe introduction of a living cover crop during a cash crop growth cycle (relay intercropping) and its maintenance after the cash crop harvest may help to preserve biodiversity, increase soil organic matter content and carbon sequestration and provide other ecosystem services, such as natural pest regulation or nutrient recycling, by increasing useful biotic interactions within the agroecosystem. We studied the impact of various approaches to manage a red fescue cover crop in a winter wheat crop in terms of light, water and nitrogen competition, using the STICS crop model adapted for intercropping. The STICS model for wheat/fescue intercropping was first evaluated on two years of experimental data obtained in the field. It gave satisfactory statistical results for the prediction of dry matter, leaf area index (LAI) and nitrogen accumulation in the two species, and for nitrogen and water dynamics in the soil. By simulating unmeasured variables, such as transpiration, the model improves our understanding of the performance of the intercrop in the field. For example, we showed that the intercropping system was more efficient that wheat grown as a sole crop, in terms of nitrogen accumulation and decreasing soil nitrogen levels before the leaching period. However, it also resulted in lower wheat yields. We then used the STICS model to compare four intercropping management scenarios differing in terms of the date of red fescue emergence, over 35 climatic years. We found that, in most climatic scenarios, the emergence of the fescue crop during the late tillering phase of the wheat crop gave the best compromise between wheat yield overall nitrogen accumulation and radiation interception

The impact of ozone exposure, temperature and CO2 on the growth and yield of three spring wheat varieties

International audienceWhen assessing potentials for crop production under future climatic conditions, multiple environmental parameters need to be included. An increase in carbon dioxide [CO2], higher temperatures, and regional changes in tropospheric ozone [O3] will influence the growth responses of existing crop species and varieties. Ozone is phytotoxic and a plant stressor at current concentrations, reducing yields worldwide, but possible interactions with changes in other abiotic factors have been considered very little. In this study, we have used eight combinations: two levels of temperature, two levels of [CO2], and three [O3] exposure regimes to assess the impact of medium-to-high ozone concentrations (80–100 ppb) on wheat growth when other abiotic factors change. Two modern spring wheat varieties (KWS Bittern and Lennox) and a landrace variety (Lantvete) were grown to maturity in climate chambers. We examined plant performance during growth as development rate, rate of photosynthesis, stomatal conductance, water use, and at harvest as total aboveground dry matter and grain yield. All three varieties lost yield in all treatments compared to the ambient treatment that had the following settings: Lowest temperature, ambient [CO2], and very low [O3]. For episodic ozone exposure in the ambient or high [CO2] and high-level temperature treatment, the yield losses were 18 and 25%, respectively, for KWS Bittern; 44 and 34% for Lennox; and 16 and 37% for Lantvete. The yields of the modern varieties are significantly higher than the landrace variety in two out of eight treatments, although they are higher by weight in seven of the eight treatments. The landrace variety’s fraction loss from its highest grain yield in the ambient treatment to the high-[CO2]-and high-level-temperature-treatments was smaller than the modern varieties’, showing a comparably higher degree of plasticity of performance. Current crop varieties might be more sensitive to ozone than older varieties, emphasizing the need of future breeding programs to expand the gene pool to provide more climate robust crops

Smoking Related Diseases: The Central Role of Monoamine Oxidase

Smoking is a major risk factor of morbidity and mortality. It is well established that monoamine oxidase (MAO) activity is decreased in smokers. Serotonin (5-HT), a major substrate for MAO that circulates as a reserve pool stored in platelets, is a marker of platelet activation. We recently reported that smoking durably modifies the platelet 5-HT/MAO system by inducing a demethylation of the MAO gene promoter resulting in high MAO protein concentration persisting more than ten years after quitting smoking. The present data enlarges the results to another MAO substrate, norepinephrine (NE), further confirming the central role of MAO in tobacco use-induced diseases. Thus, MAO could be a readily accessible and helpful marker in the risk evaluation of smoking-related diseases, from cardiovascular and pulmonary diseases to depression, anxiety and cancer. The present review implements the new finding of epigenetic regulation of MAO and suggests that smoking-induced MAO demethylation can be considered as a hallmark of smoking-related cancers similarly to other aberrant DNA methylations

Smoking-induced long-lasting modifications of human platelet serotonin catabolism through a MAO epigenetic regulation

Postulating that serotonin, secreted from smoking-activated platelets, could be involved in smoking-induced vascular modifications, we studied 115 men distributed in smokers (S), former smokers (FS) and never smokers (NS). The platelet serotonin content was similar in S and NS but lower in FS. This was unexpected because the monoamine oxidase (MAO) activity, which catabolizes serotonin, was inhibited during smoking. However, the amount of platelet MAO was higher in S and FS than in NS. The persistent elevated MAO amount in FS prompted us to study the methylation of its gene promoter in an additional series of patients: it was markedly lower for S and FS vs. NS due to cigarette smoke-induced increase of nucleic acid demethylase activity. This smoking-induced demethylation of the MAO gene promoter, resulting in high MAO amount persisting long after quitting smoking, has cardiovascular consequences and could impact fields such as behavior, mental health, and cancer

Molecular organization of the human serotonin transporter at the air/water interface

AbstractThe serotonin transporter (SERT) is the target of several important antidepressant and psychostimulant drugs. It has been shown that under defined conditions, the transporter spread at the air/water interface was able to bind its specific ligands. In this paper, the interfacial organization of the protein has been assessed from dynamic surface pressure and ellipsometric measurements. For areas comprising between 10 400 and 7100 Å2/molecule, ellipsometric measurements reveal an important change in the thickness of the SERT film. This change was attributed to the reorientation of the transporter molecules from a horizontal to their natural predictive transmembrane orientation. The thickness of the SERT film at 7100 Å2/molecule was found to be approximately equal to 84 Å and coincided well with the theoretical value estimated from the calculations based on the dimensions of α-helices containing membrane proteins. These data suggest that the three-dimensional arrangement of the SERT may be represented as a box with lengths dz=83–85 Å and dy or dx=41–47 Å

Étude biochimique et génétique des anomalies de la voie sérotonine-mélatonine comme facteurs de vulnérabilité à l autisme

Les troubles du spectre autistique (TSA) sont définis par l association de troubles des interactions sociales, de troubles du langage et de comportements stéréotypés et intérêts restreints. Cette entité recouvre en réalité des situations cliniques très hétérogènes, tant par le spectre de sévérité des symptômes que par la variété des comorbidités et signes associés. Si l étiologie génétique semble prépondérante, les mécanismes moléculaires impliqués semblent complexes et hétérogènes, et les associations génotype-phénotype inconstantes. Une stratégie possible pour décomposer cette hétérogénéité clinique et génétique consiste à s appuyer sur des endophénotypes, ou phénotypes intermédiaires, pour définir des catégories plus homogènes sur le plan physiopathologique. Parmi les nombreux endophénotypes biologiques décrits dans les TSA, l augmentation de la sérotonine sanguine est l un des mieux documentés, mais les mécanismes en sont encore inconnus. Des déficits en mélatonine (qui est un dérivé de la sérotonine) ont également été rapportés par plusieurs études. L objectif de cette thèse était de caractériser les anomalies de la voie sérotonine-mélatonine dans les TSA, et d en étudier les mécanismes et les corrélats cliniques. L exploration exhaustive de la voie sérotonine-mélatonine à partir de prélèvements sanguins dans une grande cohorte de plus de 200 patients avec TSA et leurs apparentés a permis d estimer la prévalence de l hypersérotoninémie dans les TSA à 45%, et celle du déficit en mélatonine à environ 60%. Cette étude a mis en évidence des anomalies du catabolisme de la sérotonine ainsi que des anomalies de la synthèse de la mélatonine, et a ainsi permis de proposer des mécanismes biochimiques à ces deux endophénotypes. Les anomalies de synthèse de la mélatonine, qui pourraient s accompagner d une augmentation de la N-acétylsérotonine, ont été confirmées sur des échantillons de glandes pinéales et de tractus gastro-intestinal (sources majeures de mélatonine et de sérotonine de l organisme) issus de patients avec TSA. Les gènes impliqués dans la synthèse de la mélatonine (gènes codant pour les enzymes AANAT et ASMT) ont été étudiés dans les TSA, ainsi que dans des pathologies neurodéveloppementales connexes. Les anomalies de la synthèse de mélatonine pourraient être associées aux troubles du sommeil, fréquents chez les patients avec TSAAutism Spectrum Disorders (ASD) are defined by three core symptoms: social interaction impairments, language impairments, and stereotyped behavior and restricted interests. Beyond this definition lie extremely diverse clinical situations, in terms of symptoms severity as well as comorbidities and associated features. The aetiology of ASD is considered to be mostly genetic, but the molecular mechanisms involved seem to be complex and heterogeneous, and the genotype-phenotype associations elusive. One possible strategy for decomposing the clinical and genetic complexity is to focus on endophenotypes, or intermediate phenotypes, to define more homogeneous pathophysiological categories. Among many biological endophenotypes reported in ASD, the increase of blood serotonin is well documented but still unexplained. Deficits in melatonin (which chemically derives from serotonin) have also been described. The aim of this work was to characterize the impairments of the serotonin-melatonin pathway in ASD, and to address their mechanisms and clinical correlates. Based on a comprehensive assessment of the serotonin-melatonin pathway from blood samples in a large cohort of 200 patients with ASD and their relatives, the prevalence of hyperserotonemia in ASD was estimated to be 45%, and that of melatonin deficit about 60%. Impairments of serotonin catabolism were shown, as well as impairments of melatonin synthesis, thus providing biochemical mechanisms for both endophenotypes. Abnormal melatonin synthesis, which may involve an increase in N-acetylserotonin, was confirmed on pineal gland and gastro-intestinal tract samples (i.e. the major sources of melatonin and serotonin) from patients with ASD. The genes involved in melatonin synthesis (coding for AANAT and ASMT enzymes) were studied in ASD and in related neurodevelopmental disorders. Abnormal melatonin synthesis may be associated with sleep disorders, frequently observed in patients with ASDPARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF

Rapid detection of Pseudomonas aeruginosa from positive blood cultures by quantitative PCR

<p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>is responsible for numerous bloodstream infections associated with severe adverse outcomes in case of inappropriate initial antimicrobial therapy. The present study was aimed to develop a novel quantitative PCR (qPCR) assay, using <it>ecfX </it>as the specific target gene, for the rapid and accurate identification of <it>P. aeruginosa </it>from positive blood cultures (BCs).</p> <p>Methods</p> <p>Over the period August 2008 to June 2009, 100 BC bottles positive for gram-negative bacilli were tested in order to evaluate performances of the qPCR technique with conventional methods as gold standard (i.e. culture and phenotypic identification).</p> <p>Results</p> <p>Thirty-three strains of <it>P. aeruginosa</it>, 53 strains of Enterobactericaeae, nine strains of <it>Stenotrophomonas maltophilia </it>and two other gram-negative species were isolated while 3 BCs were polymicrobial including one mixture containing <it>P. aeruginosa</it>. All <it>P. aeruginosa </it>clinical isolates were detected by qPCR except a single strain in mixed culture. Performances of the qPCR technique were: specificity, 100%; positive predictive value, 100%; negative predictive value, 98.5%; and sensitivity, 97%.</p> <p>Conclusions</p> <p>This reliable technique may offer a rapid (<1.5 h) tool that would help clinicians to initiate an appropriate treatment earlier. Further investigations are needed to assess the clinical benefit of this novel strategy as compared to phenotypic methods.</p

Intentional overdose with insulin: prognostic factors and toxicokinetic/toxicodynamic profiles

International audienc