Efficacy of fungal and bacterial antagonists for controlling growth, FUM1 gene expression and fumonisin B 1 production by Fusarium verticillioides on maize cobs of different ripening stages

This study was carried out to examine the efficacy of two biocontrol agents (Clonostachys rosea 016, BCA1; Gram-negative bacterium, BCA5) for control of FUM1 gene expression and fumonisin B1 (FB1) production by F. verticillioides FV1 on maize cobs of different ripening stages: R3, Milk (0.985 aw); R4, Dough (0.976 aw); R5, Dent (0.958 aw). Initially, temporal studies on FUM1 gene expression and FB1 production were performed on maize kernels for up to 14 days. This revealed that day 10 was optimum for both parameters, and was used in the biocontrol studies. Maize cobs were inoculated with 50:50 mixtures of the pathogen:antagonist inoculum and incubated in environmental chambers to maintain the natural aw conditions for ten days at 25 and 30 °C. The growth rates of F. verticillioides FV1, the relative expression of the FUM1 gene and FB1 production were quantified. It was found that, aw × temp had significant impacts on growth, FUM1 gene expression and FB1 production by F. verticillioides FV1 on maize cobs of different maturities. The fungal antagonist (BCA1) significantly reduced FB1 contamination on maize cobs by > 70% at 25 °C, and almost 60% at 30 °C regardless of maize ripening stage. For the bacterial antagonist (BCA5) however, FB1 levels on maize cobs were significantly decreased only in some treatments. These results suggest that efficacy of antagonists to control mycotoxin production in ripening maize cobs needs to take account of the ecophysiology of the pathogen and the antagonists, as well as the physiological status of the maize during silking to ensure effective control

Long-lived fluorescence of homopolymeric guanine–cytosine DNA duplexes

International audienceThe fluorescence spectrum of the homopolymeric double helix poly(dG)·poly(dC) is dominated by emission decaying on the nanosecond time-scale, as previously reported for the alternating homologue poly(dGdC)·poly(dGdC). Thus, energy trapping over long periods of time is a common feature of GC duplexes which contrast with AT duplexes. The impact of such behaviour on DNA photodamage needs to be evaluated

Excited state interactions between flurbiprofen and tryptophan in drug-protein complexes and in model dyads. Fluorescence studies from the femtosecond to the nanosecond time domains

International audienceWe report here on the interaction dynamics between flurbiprofen (FBP) and tryptophan (Trp) covalently linked in model dyads and in a complex of FBP with human serum albumin (HSA) probed by time-resolved fluorescence spectroscopy from the femto- to the nano-second timescales. In the dyads, a rapid (k > 1010 s−1) dynamic quenching of the 1FBP* fluorescence is followed by a slower (k > 109 s−1) quenching of the remaining 1Trp* fluorescence. Both processes display a clear stereoselectivity; the rates are 2-3 times higher for the (R,S)-dyad. In addition, a red-shifted exciplex emission is observed, rising in the range of 100-200 ps. A similar two-step dynamic fluorescence quenching is also observed in the FBP-HSA complex, although the kinetics of the involved processes are slower. The characteristic reorientational times determined for the two enantiomeric forms of FBP in the protein show that the interaction is stronger for the (R)-form. This is, to our knowledge, the first observation of stereo-selective flurbiprofen-tryptophan interaction dynamics with femtosecond time resolution

Influence of freezing temperatures prior to freeze‐drying on viability of yeasts and lactic acid bacteria isolated from wine

Aims: To determine the effect of three different freezing temperatures on post-freeze-drying survival rates of wine yeasts and lactic acid bacteria (LAB). To know if a similar freeze-drying protocol can be used for both micro- organisms. Methods and Results: Cells from liquid culture media were recovered and concentrated in appropriate lyoprotectants. Aliquots of each strain were frozen at 20, 80 and 196°C before vacuum drying. Viable cell counts were done before freezing and after freeze-drying. Survival rates were calculated. Freezing temperatures differently affected yeast and bacteria survival. The highest survival rates were obtained at 20 and 80°C for yeasts, but at 196° C for LAB. Major differences in survival rates were recorded among freeze-dried yeasts, but were less drastic for LAB. Yeasts Pichia membranifaciens, Starmerella bacillaris and Metschnikowia pulcherrima, and LAB Lactobacillus paracasei, Pediococcus parvulus and Lactobacillus mali, were the most tolerant species to freeze-drying, regardless of freezing temperature. Conclusions: Yeast and LAB survival rates differed for each tested freezing temperature. For yeasts, 20°C ensured the highest post-freeze-drying viability and 196°C for LAB. Significance and Impact of the Study: Freezing temperature to freeze-dry cells is a crucial factor for ensuring good wine yeast and LAB survival. These results are important for appropriately preserving micro-organisms and for improving starter production processes

Influence of storage environment on maize grain: CO2 production, dry matter losses and aflatoxins contamination

Poor storage of cereals, such as maize can lead to both nutritional losses and mycotoxin contamination. The aim of this study was to examine the respiration of maize either naturally contaminated or inoculated with Aspergillus flavus to examine whether this might be an early and sensitive indicator of aflatoxin (AF) contamination and relative storability risk. We thus examined the relationship between different interacting storage environmental conditions (0.80–0.99 water activity (aw) and 15–35°C) in naturally contaminated and irradiated maize grain + A. flavus on relative respiration rates (R), dry matter losses (DMLs) and aflatoxin B1 and B2 (AFB1-B2) contamination. Temporal respiration and total CO2 production were analysed by GC-TCD, and results used to calculate the DMLs due to colonisation. AFs contamination was quantified at the end of the storage period by HPLC MS/MS. The highest respiration rates occurred at 0.95 aw and 30–35°C representing between 0.5% and 18% DMLs. Optimum AFs contamination was at the same aw at 30°C. Highest AFs contamination occurred in maize colonised only by A. flavus. A significant positive correlation between % DMLs and AFB1 contamination was obtained (r = 0.866, p < 0.001) in the irradiated maize treatments inoculated with A. flavus. In naturally contaminated maize + A. flavus inoculum loss of only 0.56% DML resulted in AFB1 contamination levels exceeding the EU legislative limits for food. This suggests that there is a very low threshold tolerance during storage of maize to minimise AFB1 contamination. This data can be used to develop models that can be effectively used in enhancing management for storage of maize to minimise risks of mycotoxin contamination

Com millorar la motivació dels estudiants en assignatures de perfil economètric? una mesura pràctica amb avaluació empírica de la seva efectivitat

Projecte: 2015PID-UB/013El projecte s’ha aplicat als alumnes de les assignatures obligatòries d’Econometria I i II del Grau d’Economia de la Facultat d’Economia i Empresa al curs 2015-2016. Atesos els problemes de motivació habituals que presenten els alumnes del nostre Grau, especialment en matèries de perfil quantitatiu, el projecte ha perseguit l’objectiu general de fomentar la motivació del estudiants i l’aprenentatge actiu dels mateixos. Per tal d’aconseguir-ho vam pensar que seria possible incrementar aquesta motivació si els propis alumnes fossin la mostra estadística per l’anàlisi i aplicació de les tècniques economètriques ensenyades a classe. Així, es va pretendre motivar la participació dels alumnes mitjançant la reflexió sobre els factors determinants teòrics del seu propi rendiment acadèmic. Per fer-ho, s’ha recollit en primer lloc una base de dades dels propis alumnes sobre el seu rendiment acadèmic i les seves característiques sociodemogràfiques i familiars. Posteriorment, els alumnes han emprat aquesta base de dades per tal de construir un model economètric a partir del qual han aplicat les eines estadístic-economètriques estudiades a classe per tal d’aconseguir explicar el seu rendiment acadèmic. Atès que ells mateixos han estat la mostra d’anàlisi i el tema a analitzar era del seu interès, la participació ha estat molt elevada. Els resultats finals han sigut positius ja que ha incrementat la participació a classe i la reflexió conjunta del tema analitzat tant des d’un punt de vista teòric com aplicat. Alhora, han millorat els rendiment acadèmic general

Reproducibility of parallel preconditioned conjugate gradient in hybrid programming environments

[EN] The Preconditioned Conjugate Gradient method is often employed for the solution of linear systems of equations arising in numerical simulations of physical phenomena. While being widely used, the solver is also known for its lack of accuracy while computing the residual. In this article, we propose two algorithmic solutions that originate from the ExBLAS project to enhance the accuracy of the solver as well as to ensure its reproducibility in a hybrid MPI + OpenMP tasks programming environment. One is based on ExBLAS and preserves every bit of information until the final rounding, while the other relies upon floating-point expansions and, hence, expands the intermediate precision. Instead of converting the entire solver into its ExBLAS-related implementation, we identify those parts that violate reproducibility/non-associativity, secure them, and combine this with the sequential executions. These algorithmic strategies are reinforced with programmability suggestions to assure deterministic executions. Finally, we verify these approaches on two modern HPC systems: both versions deliver reproducible number of iterations, residuals, direct errors, and vector-solutions for the overhead of less than 37.7% on 768 cores.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was partially supported by the European Union's Horizon 2020 research, innovation program under the Marie Sklodowska-Curie grant agreement via the Robust project No. 842528 as well as the Project HPC-EUROPA3 (INFRAIA-2016-1-730897), with the support of the H2020 EC RIA Programme; in particular, the author gratefully acknowledges the support of Vicenc comma Beltran and the computer resources and technical support provided by BSC. The researchers from Universitat Jaume I (UJI) and Universitat Polit ' ecnica de Valencia (UPV) were supported by MINECO project TIN2017-82972-R. Maria Barreda was also supported by the POSDOC-A/2017/11 project from the Universitat Jaume I.Iakymchuk, R.; Barreda Vayá, M.; Graillat, S.; Aliaga, JI.; Quintana Ortí, ES. (2020). Reproducibility of parallel preconditioned conjugate gradient in hybrid programming environments. International Journal of High Performance Computing Applications. 34(5):502-518. https://doi.org/10.1177/1094342020932650S502518345Aliaga, J. I., Barreda, M., Flegar, G., Bollhöfer, M., & Quintana-Ortí, E. S. (2017). Communication in task-parallel ILU-preconditioned CG solvers using MPI + OmpSs. Concurrency and Computation: Practice and Experience, 29(21), e4280. doi:10.1002/cpe.4280Bailey, D. H. (2013). 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Proceedings 15th IEEE Symposium on Computer Arithmetic. ARITH-15 2001. doi:10.1109/arith.2001.930115Hunold, S., & Carpen-Amarie, A. (2016). Reproducible MPI Benchmarking is Still Not as Easy as You Think. IEEE Transactions on Parallel and Distributed Systems, 27(12), 3617-3630. doi:10.1109/tpds.2016.2539167IEEE Computer Society (2008) IEEE Standard for Floating-Point Arithmetic. Piscataway: IEEE Standard, pp. 754–2008.Kulisch, U., & Snyder, V. (2010). The exact dot product as basic tool for long interval arithmetic. Computing, 91(3), 307-313. doi:10.1007/s00607-010-0127-7Kulisch, U. (2013). Computer Arithmetic and Validity. doi:10.1515/9783110301793Lawson, C. L., Hanson, R. J., Kincaid, D. R., & Krogh, F. T. (1979). Basic Linear Algebra Subprograms for Fortran Usage. ACM Transactions on Mathematical Software, 5(3), 308-323. doi:10.1145/355841.355847Lutz, D. R., & Hinds, C. N. (2017). High-Precision Anchored Accumulators for Reproducible Floating-Point Summation. 2017 IEEE 24th Symposium on Computer Arithmetic (ARITH). doi:10.1109/arith.2017.20Mukunoki, D., Ogita, T., & Ozaki, K. (2020). Reproducible BLAS Routines with Tunable Accuracy Using Ozaki Scheme for Many-Core Architectures. Lecture Notes in Computer Science, 516-527. doi:10.1007/978-3-030-43229-4_44Nguyen, H. D., & Demmel, J. (2015). Reproducible Tall-Skinny QR. 2015 IEEE 22nd Symposium on Computer Arithmetic. doi:10.1109/arith.2015.28Ogita, T., Rump, S. M., & Oishi, S. (2005). Accurate Sum and Dot Product. SIAM Journal on Scientific Computing, 26(6), 1955-1988. doi:10.1137/030601818Ozaki, K., Ogita, T., Oishi, S., & Rump, S. M. (2011). Error-free transformations of matrix multiplication by using fast routines of matrix multiplication and its applications. Numerical Algorithms, 59(1), 95-118. doi:10.1007/s11075-011-9478-1Priest, D. M. (s. f.). Algorithms for arbitrary precision floating point arithmetic. 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Avaluació de l'obertura dels comerços als diumenges d'estiu a la ciutat de Barcelona : informe

Informe presentat a la Comissió d'Economia, Empresa i Ocupació de 19-11-2014Informe elaborat per: AQR-Lab-Laboratori de Transferència en Economia Aplicada a la UBEquip investigador: Jordi Suriñach (dir.), Jordi López Tamayo, Esther Vay

A comparison of Covid-19 early detection between convolutional neural networks and radiologists

[EN] Background The role of chest radiography in COVID-19 disease has changed since the beginning of the pandemic from a diagnostic tool when microbiological resources were scarce to a different one focused on detecting and monitoring COVID-19 lung involvement. Using chest radiographs, early detection of the disease is still helpful in resource-poor environments. However, the sensitivity of a chest radiograph for diagnosing COVID-19 is modest, even for expert radiologists. In this paper, the performance of a deep learning algorithm on the first clinical encounter is evaluated and compared with a group of radiologists with different years of experience. Methods The algorithm uses an ensemble of four deep convolutional networks, Ensemble4Covid, trained to detect COVID-19 on frontal chest radiographs. The algorithm was tested using images from the first clinical encounter of positive and negative cases. Its performance was compared with five radiologists on a smaller test subset of patients. The algorithm's performance was also validated using the public dataset COVIDx. Results Compared to the consensus of five radiologists, the Ensemble4Covid model achieved an AUC of 0.85, whereas the radiologists achieved an AUC of 0.71. Compared with other state-of-the-art models, the performance of a single model of our ensemble achieved nonsignificant differences in the public dataset COVIDx. Conclusion The results show that the use of images from the first clinical encounter significantly drops the detection performance of COVID-19. The performance of our Ensemble4Covid under these challenging conditions is considerably higher compared to a consensus of five radiologists. Artificial intelligence can be used for the fast diagnosis of COVID-19.Project Chest screening for patients with COVID 19 (COV2000750 Special COVID19 resolution) funded by Instituto de Salud Carlos III. Project DIRAC (INNVA1/2020/42) funded by the Agencia Valenciana de la Innovacion, Generalitat Valenciana.Albiol Colomer, A.; Albiol, F.; Paredes Palacios, R.; Plasencia-Martínez, JM.; Blanco Barrio, A.; García Santos, JM.; Tortajada, S.... (2022). A comparison of Covid-19 early detection between convolutional neural networks and radiologists. Insights into Imaging. 13(1):1-12. https://doi.org/10.1186/s13244-022-01250-311213