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Investigation of the thermophysical properties of binary system CO 2 and Hydro-fluoro-olefins
No full textInternational audienc
GhERF-IIb3 regulates the accumulation of jasmonate and leads to enhanced cotton resistance to blight disease.
No full textInternational audienceThe phytohormone jasmonic acid (JA) and its derivatives, collectively referred to as jasmonates, regulate many developmental processes, but are also involved in response to numerous abiotic/biotic stresses. Thus far, powerful reverse genetic strategies employing perception, signaling or biosynthesis mutants have broadly contributed to our understanding of JA implication in plant stress response and development; so did the chemical gain-of-function approach based on exogenous application of the hormone. However, there is currently no method that allows for in planta tightly controlled JA production. Investigating the control of the JA synthesis pathway in bacteria-infected cotton (Gossypium hirsutum L.) plants, we identified a transcription factor (TF), namely GhERF-IIb3, that could act as positive regulator of the JA pathway. Expression of this well-conserved TF in cotton leaves was sufficient to bring about in situ JA accumulation at physiological concentrations associated with enhanced cotton defense response to bacterial infection
Headspace solid-phase microextraction for wine volatile analysis
No full textThe most commonly used technique to prepare samples for the analysis of wine volatile is the headspace solid-phase microextraction (HS-SPME). This method has gained popularity in last few years, as it is a unique solventless preparation technique. In this paper, a summary of recently published studies using HS-SPME for the analysis of wine aromas, with special emphasis on the method developed, has been compiled. Several papers are discussed in detail, mainly with respect to the SPME conditions used. A brief summary of the reviews related to HS-SPME analysis is given and discussed. Several parameters affecting the HS-SPME, such as the salt concentration and the agitation conditions, are used in the same way as used in several papers. The HS-SPME extraction proved to be sufficiently sensitive to satisfy legislative requirements related to low detection and quantification limits as well as method accuracy and precision requirements. However, in order to achieve the best performance and precision, the protocol needs to be optimized for each case. The effect of different parameters must be well characterized to ensure correct extraction and desorption to ensure the transfer of extracted compounds into the analytical system. The operating parameters, such as time, temperature, and agitation, must then be kept constant for all the samples
Design for the transfer of a validated liquid chromatography/tandem mass spectrometry analytical method for the determination of antimicrobial residues in honey from low-resolution to high-resolution mass spectrometry
No full textInternational audienceRATIONALE: This paper investigates the validity of the transfer of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of veterinary medicinal products in honey and compares it with an LC/linear ion trap/Orbitrap mass spectrometry method. A descriptive statistical approach was used in order to assess whether such a transfer would succeed or fail. This approach is based on the simultaneous evaluation of the trueness and of the intermediate precision for each compound at a 95% interval of confidence of both analytical techniques. METHODS: Two grams of honey were placed in a centrifuge tube and diluted with 2.5 mL of ultra-pure water and 2.5 mL of acidified methanol with hydrochloric acid at 2 mol.mL-1 . The extract was purified with 50 mg of primary secondary amine and then analyzed using LC/MS/MS in multiple reaction monitoring (MRM) mode and LC/orbitrap high-resolution mass spectrometry in full scan mode. Both analytical techniques were compared by using the descriptive statistical approach for the determination of antimicrobial residues in honey. RESULTS: The transfer of the method showed that the Orbitrap system provides the same accurate analytical results compared with the LC/MS/MS method except for 4-epitetracycline, anhydroerythromycin A, erythromycin A enol ether, and dihydrostreptomycin. Furthermore, the LC/LTQ-Orbitrap system is capable of successfully competing with the LC/MS/MS method by additional provision of high mass resolution and mass accuracy even though it shows less sensitivity compared with the LC/MS/MS instrument. CCalpha levels for most analytes were 1.3 times higher by LC/MS/MS than those observed by LC/LTQ-Orbitrap. The method was assessed in terms of relative bias through analysis of a reference material provided by FAPAS (Food Analysis Performance and Assessment Scheme) and also through the control of several contaminated honey samples from local Lebanese markets. Satisfactory relative bias was below 22% except for tetracycline found in one sample that showed a higher bias at 29%. CONCLUSIONS: The LC/LTQ-Orbitrap method offers adequate performance in comparison with previously validated method on a LC/MS/MS system resulting in acceptance of the transfer of the method from LC/MS/MS to LC/LTQ-Orbitrap
The impact of religious practice on stock returns and volatility
No full textInternational audienceWith a psychological and behavioral perspective, this paper examines whether religious practice, through its influence on investors' moods and emotions, affect the behavior of the stock markets and investors in 15 Islamic countries over the period December 31, 2005 to December 31, 2015 and over four sub-periods (before and after both the global financial crisis and the Arab spring). The results indicate that volatility decreases during the month of Ramadan and is significantly different from the volatility observed in the other 11months of the Islamic calendar year in most Muslim countries. We also identify that changes in stock returns and volatility during the month of Ramadan are related to religious practice and not due to the global financial crisis or the Arab spring. The findings significantly improve the understanding of the role of religious practice on stock market behavior and as such may be of great interest to investors and market regulators
Bitcoin for energy commodities before and after the December 2013 crash: diversifier, hedge or safe haven?
No full textInternational audienceWe study the relationship between Bitcoin and commodities by assessing the ability of Bitcoin to act as a diversifier, hedge, or safe haven against daily movements in commodities in general, and energy commodities in particular. We focus on energy commodities because energy, in the form of electricity, is an essential input in the Bitcoin production. For the entire period, results show that Bitcoin is a strong hedge and a safe-haven against movements in both commodity indices. We further examine whether that ability is also present for non-energy commodities and our analysis show insignificant results when energy commodities are excluded from the general commodity index. We also account for the December 2013 Bitcoin price crash and our results reveal that Bitcoin hedge and safe-haven properties against commodities and energy commodities are only present in the pre-crash period, whereas in the post-crash period Bitcoin is no more than a diversifier. In addition to uncovering the time-varying role of Bitcoin, we highlight the dissimilarity in the dynamic correlations between the extreme downward and extreme upward movements
Feasibility and efficacy of a new approach for controlling populations of the rosy apple aphid, Dysaphis plantaginea Passerini (Hemiptera: Aphididae) in south-eastern France
No full textEpisyrphus balteatus De Geer (Diptera: Syrphidae) is one of the most efficient biocontrol agents against Dysaphis plantaginea Passerini (Hemiptera: Aphididae) in apple orchards due to its early arrival. However, releasing flying predators in open orchards may be risky. We thus evaluated the combined effects of biological (early release of syrphids) and physical (Alt'Carpo nets) methods for controlling aphids under orchard conditions assuming that syrphids released under the nets will be able to survive and reproduce. Five experimental treatments containing two rows of trees each were set up in a pesticide-free orchard containing two different apple cultivars. For each cultivar, E. Balteatus adults were released (25, 40 and 90 adults per row) into three treatments, which were covered with nets, and two treatments were maintained free as controls (with and without nets). The releases, mainly in treatment 90, had a small effect on the development of the aphid population compared to netted control trees, especially towards the end of the study period when some of the differences were significant. This study demonstrated that E. balteatus adults can be successfully released under nets since we did observe an accumulation in the offspring of released individuals, mainly in treatments 40 and 90
Development and validation of a multiclass method for the determination of antibiotic residues in honey using liquid chromatography-tandem mass spectrometry
No full textInternational audienceA new, simple and fast method was developed for the determination of multi-class antibiotic residues in honey (sulfonamides, tetracyclines, macrolides, lincosamides and aminoglycosides). Separation and determination were carried out by LC-MS/MS. During sample preparation, various parameters affecting extraction efficiency were examined, including the type of solvent, pH, efficiencies of cleavage of N-glycosidic linkages by hydrochloric acid, ultrasonic extraction and its duration compared with shaking, along with dispersive SPE clean-up. Experiments with fortified samples demonstrated that 10 min of ultrasonic treatment with acidified methanol (HCl 2 M) followed by dispersive SPE clean-up with 50 mg PSA gave an effective sample preparation method for several classes of antibiotics in honey. Anhydroerythromycin A, erythromycin A enol ether and desmycosin were used as markers for the presence of erythromycin A and tylosin A in honey samples. The method was validated according to European Commission Decision (EC) No. 2002/657. The recoveries of analytes ranged from 85% to 111%. Repeatability and intra-laboratory reproducibility were < 20.6% and 26.8%, respectively. Decision limit (CCα) and detection capability (CCβ) ranged from 6 to 9 µg kg– 1 and from 7 to 13 µg kg– 1, respectively, except for streptomycin and neomycin, which showed slightly higher CCα at 25 µg kg– 1 and CCβ at 34 µg kg– 1. Finally, the method was applied to the honey test material 02270 through a FAPAS proficiency test (PT) for the determination of tetracyclines. PT results were obtained within a z-score range of ±2, proving that the validated method is suitable for routine analysis to ensure the quality of honey
Genome-wide association analysis implicates dysregulation of immunity genes in chronic lymphocytic leukaemia.
No full textInternational audienceSeveral chronic lymphocytic leukaemia (CLL) susceptibility loci have been reported; however, much of the heritable risk remains unidentified. Here we perform a meta-analysis of six genome-wide association studies, imputed using a merged reference panel of 1,000 Genomes and UK10K data, totalling 6,200 cases and 17,598 controls after replication. We identify nine risk loci at 1p36.11 (rs34676223, P=5.04 × 10(-13)), 1q42.13 (rs41271473, P=1.06 × 10(-10)), 4q24 (rs71597109, P=1.37 × 10(-10)), 4q35.1 (rs57214277, P=3.69 × 10(-8)), 6p21.31 (rs3800461, P=1.97 × 10(-8)), 11q23.2 (rs61904987, P=2.64 × 10(-11)), 18q21.1 (rs1036935, P=3.27 × 10(-8)), 19p13.3 (rs7254272, P=4.67 × 10(-8)) and 22q13.33 (rs140522, P=2.70 × 10(-9)). These new and established risk loci map to areas of active chromatin and show an over-representation of transcription factor binding for the key determinants of B-cell development and immune response
Does Bitcoin hedge global uncertainty? Evidence from wavelet-based quantile-in-quantile regressions
No full textInternational audienceWe examine whether Bitcoin can hedge global uncertainty, measured by the first principal component of the VIXs of 14 developed and developing equity markets. After decomposing Bitcoin returns into various frequencies, i.e., investment horizons, and given evidence of heavy-tails, we employ quantile regression. We reveal that Bitcoin does act as a hedge against uncertainty: it reacts positively to uncertainty at both higher quantiles and shorter frequency movements of Bitcoin returns. Further, we use quantile-on-quantile regression and identify that hedging is observed at shorter investment horizons, and at both lower and upper ends of Bitcoin returns and global uncertainty