Effets du type de fertilisation sur la productivité du Jatropha curcas en zone des savanes d'Afrique Centrale cas de la localité de Sanguéré Paul au Nord Cameroun

Objectifs : L'essai a été conduit sur le site expérimental de l'IRAD station polyvalente de Garoua à Sanguéré Paul au Nord Cameroun. Il a été mise en place en juillet 2009. Il visait à étudier la courbe de réponse du jatropha à la fumure organique et/ou à la fumure minérale (N.P.K.) par rapport au témoin sans fertilisation. Méthodologie et Résultats : Le dispositif expérimental est du type blocks de Fischer randomisés à un facteur de 3 traitements (0 engrais, 200 kg/ha de N.P.K.et 5T de fumier) avec 8 répétitions. Différents paramètre s ont été étudiés notamment le pourcentage de survie des plants après 5 ans, les paramètres de morphologique (hauteur, diamètre des plants, nombre de ramifications) et les paramètres de rendement dont notamment le rendement des graines par plant puis une l'évaluation séparée du rendement par hectare pour chaque traitement. Les analyses des résultats effectuées par le STATBOX et le test de Student-Newman-Keul's Multiple (P=0.05) ont permis de montrer que la fertilisation a eu un effet significatif sur la hauteur des plants les deux 1éres années et pas d'effet sur les trois dernières années. Par contre elle a eu un effet significatif sur les cinq années d'observations sur le diamètre, le nombre de ramifications, le rendement en graine par pla nt et à l'hectare. Toutefois l'engrais minéral s'est avéré meilleur les deux 1éres années sur la hauteur (83,3 2 cm en 2010 et 150 cm en 2014), et pas de différence significative les trois années suivantes. Pourtant la fertilisation a eu un effet significatif pendant les cinq années d'observation sur le diamètre au collet, le nombre de ramification, le rendement par plant et par hectare en passant de 41,55 mm en 2010 à 101 mm en 2014 ; 4,77 en 2010 à 32,25 en 2014 ; 26,66g en 2010 à 648,82g en 2014 par plant et 66,16 kg/ha en 2010 à 1622 kg/ ha en 2014 respectivement par rapport au témoin. Conclusion et application des résultats : Ces résultats montrent que le Jatropha curcas considéré comme une plante de zone marginale qui ne nécessite pas la fertilisation, répond positivement à une fertilisation aussi bien organique que minérale. Cette fertilisation améliore nettement aussi bien les paramètres morphologiques que par le rendement

Impact of decitabine on immunohistochemistry expression of the putative tumor suppressor genes FHIT, WWOX, FUS1 and PTEN in clinical tumor samples.

BackgroundSince tumor suppressor gene function may be lost through hypermethylation, we assessed whether the demethylating agent decitabine could increase tumor suppressor gene expression clinically. For fragile histidine triad (FHIT), WW domain-containing oxidoreductase (WWOX), fused in sarcoma-1 (FUS1) and phosphatase and tensin homolog (PTEN), immunohistochemistry scores from pre- and post-decitabine tumor biopsies (25 patients) were correlated with methylation of the long interspersed nuclear element-1 (LINE-1) repetitive DNA element (as a surrogate for global DNA methylation) and with tumor regression.ResultsWith negative staining pre-decitabine (score = 0), the number of patients converting to positive staining post-decitabine was 1 of 1 for FHIT, 3 of 6 for WWOX, 2 of 3 for FUS1 and 1 of 10 for PTEN. In tumors with low pre-decitabine tumor suppressor gene scores (≤150), expression was higher post-treatment in 8 of 8 cases for FHIT (P = 0.014), 7 of 17 for WWOX (P = 0.0547), 7 of 12 for FUS1 (P = 0.0726), and 1 of 16 for PTEN (P = 0.2034). If FHIT, WWOX and FUS1 were considered together, median pre- versus post-decitabine scores were 60 versus 100 (P = 0.0002). Overall, tumor suppressor gene expression change did not correlate with LINE-1 demethylation, although tumors converting from negative to positive had a median decrease in LINE-1 methylation of 24%, compared to 6% in those not converting (P = 0.069). Five of 15 fully evaluable patients had reductions in tumor diameter (range 0.2% to 33.4%). Of these, three had simultaneous increases in three tumor suppressor genes (including the two patients with the greatest tumor regression) compared to 2 of 10 with tumor growth (P = 0.25).ConclusionsIn tumors with low tumor suppressor gene expression, decitabine may be associated with increased expression of the tumor suppressor genes FHIT, FUS1, and WWOX, but not PTEN

Distinguishing Originality from Creativity in ADHD: An Assessment of Creative Personality, Self-Perception, and Cognitive Style among Attention-Deficit/Hyperactivity Disorder Adults

Debates over whether Attention-Deficit/Hyperactivity Disorder (ADHD) relates to high levels of creativity have been hampered by a lack of rigor when defining creativity. The purpose of the present study was to go beyond the rhetoric by empirically investigating creative personality, creative self-perception, and cognitive style among 49 ADHD adults. Comparative analysis to studies of non-ADHD samples revealed distinctive tendencies: A mean group score of 115.71 (SD=18.02) on the Kirton Adaption-Innovation Inventory (KAI) indicated preferences for originality, nonconformity, paradigm-breaking, and low efficiency that was over one standard deviation higher than average non-ADHD population scores. Combined inattentive/hyperactiveimpulsive subtypes (n=20) scored 124.30 (SD=12.96). Ideator tendencies on Puccio’s FourSight indicated preferences for generating novel ideas and overlooking details. Adjective Check List (ACL) scores were slightly elevated on the Domino Creative Personality and Gough Creativity scales, but more so on the Change scale, indicating a tendency to seek novelty and avoid routine. Creative self-perception was high, with 85.71% reporting themselves as more creative than average. Although their dispositions toward originality might benefit creativity, it might be undermined by their disinclination for effectiveness necessary for full-fledged creativity. Results may help clinicians distinguish maladaptive ADHD behaviors from concomitant behaviors that might play a valuable role in creativity

Tackling the methylome: recent methodological advances in genome-wide methylation profiling

DNA methylation of promoter CpG islands is strongly associated with gene silencing and is known as a frequent cause of loss of expression of tumor suppressor genes, as well as other genes involved in tumor formation. DNA methylation of driver genes is very likely outnumbered by the number of methylated passenger genes, though these can be useful as tumor markers. Much of what is known about the importance of DNA methylation in cancer was gained through small- and moderate-scale analysis of gene promoters and tumor samples. A much better understanding of the role of DNA methylation in cancer, either as a marker of disease or as an active driver of tumorigenesis, will likely be gained from genome-wide studies of this modification in normal and malignant cells. This goal has become more attainable with the recent introduction of large-scale genome analysis methodologies and these have been modified to allow for investigation of DNA methylation. Several research groups have been formed to coordinate efforts and apply these methodologies to decipher the methylome of healthy and diseased tissues. In this article we review technological advances in genome-wide methylation profiling

Phase I study of azacitidine and oxaliplatin in patients with advanced cancers that have relapsed or are refractory to any platinum therapy.

BackgroundDemethylation process is necessary for the expression of various factors involved in chemotherapy cytotoxicity or resistance. Platinum-resistant cells may have reduced expression of the copper/platinum transporter CTR1. We hypothesized that azacitidine and oxaliplatin combination therapy may restore platinum sensitivity. We treated patients with cancer relapsed/refractory to any platinum compounds (3 + 3 study design) with azacitidine (20 to 50 mg/m(2)/day intravenously (IV) over 15 to 30 min, D1 to 5) and oxaliplatin (15 to 30 mg/m(2)/day, IV over 2 h, D2 to 5) (maximum, six cycles). Platinum content, LINE1 methylation (surrogate of global DNA methylation), and CTR1 expression changes (pre- vs. post-treatment) were assessed. Drug pharmacokinetics were analyzed.ResultsThirty-seven patients were treated. No dose-limiting toxicity (DLT) was noted at the maximum dose. The most common adverse events were anemia and fatigue. Two (5.4%) patients had stable disease and completed six cycles of therapy. Oxaliplatin (D2) and azacitidine (D1 and 5) mean systemic exposure based on plasma AUCall showed dose-dependent interaction whereby increasing the dose of oxaliplatin reduced the mean azacitidine exposure and vice versa; however, no significant differences in other non-compartmental modeled parameters were observed. Blood samples showed universal reduction in global DNA methylation. In tumor samples, hypomethylation was only observed in four out of seven patients. No correlation between blood and tumor demethylation was seen. The mean cytoplasmic CTR1 score decreased. The pre-dose tumor oxaliplatin levels ranged from <0.25 to 5.8 μg/g tumor. The platinum concentration increased 3- to 18-fold. No correlation was found between CTR1 score and oxaliplatin level, which was found to have a trend toward correlation with progression-free survival.ConclusionsOxaliplatin and azacitidine combination therapy was safe. CTR1 expression was not correlated with methylation status or tissue platinum concentration

Methylation of HIN-1, RASSF1A, RIL and CDH13 in breast cancer is associated with clinical characteristics, but only RASSF1A methylation is associated with outcome

BACKGROUND: Aberrant promoter CpG island hypermethylation is associated with transcriptional silencing. Tumor suppressor genes are the key targets of hypermethylation in breast cancer and therefore may lead to malignancy by deregulation of cell growth and division. Our previous pilot study with pairs of malignant and normal breast tissues identified correlated methylation of two pairs of genes - HIN-1/RASSFIA and RIL/CDH13 - with expression of estrogen receptors (ER), progesterone receptors (PR), and HER2 (HER2). To determine the impact of methylation on clinical outcome, we have conducted a larger study with breast cancers for which time to first recurrence and overall survival are known. METHODS: Tumors from 193 patients with early stage breast cancer who received no adjuvant systemic therapy were used to analyze methylation levels of RIL, HIN-1, RASSF1A and CDH13 genes for associations with known predictive and prognostic factors and for impact on time to first recurrence and overall survival. RESULTS: In this study, we found that ER was associated with RASSF1A methylation (p < 0.001) and HIN-1 methylation (p = 0.002). PR was associated with RIL methylation (p = 0.012), HIN-1 (p = 0.002), and RASSF1A methylation (p = 0.019). Tumor size was associated with RIL and CDH13 methylation (both p = 0.002), and S-phase was associated with RIL methylation (p = 0.036). Only RASSF1A was associated with worse time to first recurrence (p = 0.045) and worse overall survival (p = 0.016) after adjusting for age, tumor size, S-phase, estrogen receptor and progesterone receptor. CONCLUSIONS: Methylation of HIN-1, RASSF1A, RIL and CDH13 in breast cancers was associated with clinical characteristics, but only RASSF1A methylation was associated with time to first recurrence and overall survival. Our data suggest that RASSF1A methylation could be a potential prognostic biomarker

Atlas des évolutions des systèmes pastoraux au Sahel : 1970-2012

Le présent Atlas fait la synthèse des informations disponibles sur les transformations des systèmes pastoraux au Sahel, collectées dans le contexte du SIPSA ou par d'autres initiatives. Partant d'une analyse des besoins en information conduite dans le cadre du SIPSA, l'atlas analyse les grandes tendances de l'élevage pastoral et de son contexte. Au regard des impacts des conditions climatiques sur les économies au Sahel, il apparait indispensable de disposer d'analyse prospective sur les différents secteurs des économies des pays du Sahel. Tel est le mérite de cet atlas, un excellent outil qui permettra la prise de décision fondée sur des bases objectives et assurera l'amélioration certaine de la gouvernance du secteur de l'élevage pastoral sahélien

Estimation de facteurs de Bayes entre modèles dynamiques non linéaires à espace d'état

aeres : ACLInternational audienceLes modèles non linéaires à espace d'état sont utilisés de façon croissante pour représenter de nombreux systèmes dynamiques stochastiques et pour les contrôler. De nouveaux outils de filtrage particulaire sont maintenant disponibles pour l'identification de ces modèles. Il n'en va pas de même pour le problème de leur sélection statistique car les vraisemblances associées sont le plus souvent non accessibles et d'estimation difficile. Ceci exclut a priori les critères classiques de comparaison de modèles de type Akaïke et compromet l'utilisation des méthodes performantes basées sur l'estimation d'un facteur de Bayes par simulations MCMC. Cette Note propose un estimateur convergent non paramétrique d'un facteur de Bayes pour ces modèles, comme application directe de ces nouveaux filtres particulaires. The use of nonlinear state space models in the study and control of stochastic dynamic systems is regularly growing. With the new generation of particle filters, efficient filtering methods are now available for the identification of these models. However their statistical selection is still an open problem because of the frequent nonaccessibility of the related likelihoods and the intricate estimation of the latter. This rules out all the usual model comparison information criteria as Akaïke's and unfavour also the efficient methods relying on Bayes factor estimation by MCMC simulations