249 research outputs found

    DNA quantification to assess Zymoseptoria tritici on a susceptible cultivar of durum wheat to establish the best timing for fungicide application in an italian environment

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    Zymoseptoria tritici, a globally distributed pathogen, is responsible of Septoria tritici blotch (STB), one of the most damaging wheat diseases. In Italy the incidence of STB has increased during the past few years. The presence of Z. tritici on flag leaves of susceptible durum wheat plants, cultivar San Carlo, after a single artificial inoculation with two inoculum concentrations at different vegetative stages has been evaluated in the plain of Bologna (North of Italy), in a two year field study (2012–2013). The pathogen presence was also assessed in natural infection conditions after a fungicide application in the second year (2013). The results obtained, by visual examination (Incidence, Disease Severity) and DNA quantification by Real time PCR, demonstrated that BBCH 39 (flag leaf stage) is the most susceptible vegetative stage, independently of inoculum concentration and climatic conditions. A good correlation between Disease Severity and DNA quantity was observed in either sampling methods, entire flag leaves and flag leaf discs. Thereafter the most suitable period to obtain the best crop protection with only one fungicide treatment is the flag leaf stage

    Extending Bauer's corollary to fractional derivatives

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    We comment on the method of Dreisigmeyer and Young [D. W. Dreisigmeyer and P. M. Young, J. Phys. A \textbf{36}, 8297, (2003)] to model nonconservative systems with fractional derivatives. It was previously hoped that using fractional derivatives in an action would allow us to derive a single retarded equation of motion using a variational principle. It is proven that, under certain reasonable assumptions, the method of Dreisigmeyer and Young fails.Comment: Accepted Journal of Physics A at www.iop.org/EJ/journal/JPhys

    Combined flow-based imaging assessment of optimal cardiac resynchronization therapy pacing vector: A case report

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    Background: There are still many pendent issues about the effective evaluation of cardiac resynchronization therapy impact on functional mitral regurgitation. In order to reduce the intrinsic difficulties of quantification of functional mitral regurgitation itself, an automatic quantification of real-time three-dimensional full-volume color Doppler transthoracic echocardiography was proposed as a new, rapid, and accurate method for the assessment of functional mitral regurgitation severity. Recent studies suggested that images of left ventricle flow by echo-particle imaging velocimetry could be a useful marker of synchrony. Echo-particle imaging velocimetry has shown that regional anomalies of synchrony/synergy of the left ventricle are related to the alteration, reduction, or suppression of the physiological intracavitary pressure gradients. Case summary: We describe a case in which the two technologies are used in combination during acute echocardiographic optimization of left pacing vector in a 63-year-old man, Caucasian, who showed worsening heart failure symptoms a few days after an implant, and the effect of the device\u2019s optimization at 6-month follow-up. Discussion: The degree of realignment of hemodynamic forces, with quantitative analysis of the orientation of blood flow momentum (\u3c6), can represent improvement of fluid dynamics synchrony of the left ventricle, and explain, with a new deterministic parameter, the effects of cardiac resynchronization therapy on functional mitral regurgitation. Realtime three-dimensional color flow Doppler quantification is feasible and accurate for measurement of mitral inflow, left ventricular outflow stroke volumes, and functional mitral regurgitation severity. Conclusion: This clinical case offers an innovative and accurate approach for acute echocardiographic optimization of left pacing vector. It shows clinical utility of combined three-dimensional full-volume color Doppler transthoracic echocardiography/echo-particle imaging velocimetry assessment to increase response to cardiac resynchronization therapy, in terms of reduction of functional mitral regurgitation, improving fluid dynamics synchrony of the left ventricle

    A Variational Procedure for Time-Dependent Processes

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    A simple variational Lagrangian is proposed for the time development of an arbitrary density matrix, employing the "factorization" of the density. Only the "kinetic energy" appears in the Lagrangian. The formalism applies to pure and mixed state cases, the Navier-Stokes equations of hydrodynamics, transport theory, etc. It recaptures the Least Dissipation Function condition of Rayleigh-Onsager {\bf and in practical applications is flexible}. The variational proposal is tested on a two level system interacting that is subject, in one instance, to an interaction with a single oscillator and, in another, that evolves in a dissipative mode.Comment: 25 pages, 4 figure

    Design of a Low‐Power Radio Frequency Unit and Its Application for Bacterial Inactivation under Laboratory Conditions

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    A lab‐scale low‐power free‐running radio frequency (RF) oscillator operating at a frequency of 27.12 ± 0.50 MHz was developed to be suitable for fundamental microbiological research topics. Calibration and validation were conducted for two common foodborne pathogens in relevant microbiological growth media, i.e., Salmonella Typhimurium and Listeria monocytogenes in Tryptic Soy Broth and Brain–Heart Infusion broth, respectively. The evolution of temperature, frequency, and power consumption was monitored during treatments, both with and without bacterial cells. The setup operated within the predefined frequency range, reaching temperatures of 71–76 °C after 15 min. The average power consumption ranged between 12 and 14 W. The presence of bacteria did not significantly influence the operational parameters. The inactivation potential of the RF setup was validated, demonstrating the absence of viable cells after 8 and 10 min of treatment, for S. Typhimurium and L. monocytogenes, respectively. In future studies, the setup can be used to conduct fundamental microbiological studies on RF inactivation. The setup can provide added value to the scientific field, since (i) no consensus has been reached on the inactivation mechanisms of RF inactivation of pathogens in foods and (ii) most commercial RF setups are unsuitable to adopt for fundamental studies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was funded by the KU Leuven Research Fund through project C24/18/046, by the Research Foundation Flanders (FWO) through project G0B4121N, and by the EU H2020 research and innovation program under the Marie Skłodowska‐Curie grant agreement no. 956126. Authors Davy Verheyen and Simen Akkermans were funded by the Research Foundation Flanders (FWO), grant numbers 1254421N and 1224620N, respectively

    Determination of deoxynivalenol and nivalenol producing chemotypes of Fusarium graminearum isolated from durum wheat in different Italian regions

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    Durum wheat production in Italy is economically of great importance. Fusarium graminearum is the main fusarium head blight (FHB) causal agent in wheat, reducing both yield and grain quality. F. graminearum produces several mycotoxins and, among trichothecenes, deoxynivalenol (DON) and nivalenol (NIV) are the most studied for their toxicity towards humans and animals. DON-producing isolates can be further distinguished on the basis of the predominant acetyl-DON derivative in 3-acetyldeoxynivalenol (3-ADON) or 15acetyldeoxynivalenol (15-ADON). In order to evaluate possible mycotoxin contamination risks in food, it is very important to know which chemotype is the prevalent in a F. graminearum population. F. graminearum sensu stricto strains were collected from symptomatic durum wheat heads and grains of several naturally infected fields located mostly in Emilia – Romagna, The Marche, Lazio, Tuscany and Umbria. A multiplex PCR in the region of genes Tri12, located in the terminal gene cluster of trichothecenes, was used to characterize 187 single-spore isolates of F. graminearum as NIV, 3-ADON and 15-ADON chemotypes. All the three chemotypes were present in the F. graminearum population studied. The most frequent chemotype was 15-ADON (83.4%), followed by 3-ADON (10.7%) and NIV (5.9%). NIV-producing isolates were found only in Emilia-Romagna (3.5%), Umbria (33.3%) and The Marche (5.7%)
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