2,007 research outputs found

    Evidence of olive mild mosaic virus transmission by Olpidium brassicae

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    Transmission of three strains of OMMV by an Olpidium sp. was evaluated and compared. The three strains were 1) an OMMV wild type (WT) recovered from olive trees, 2) an OMMV variant (L11) obtained after 15 serial passages of single local lesions induced in Chenopodium murale plants, and 3) a construct OMMV/OMMVL11 in which the coat protein (CP) gene replaced that of the wild type. A single-sporangial culture derived from Chinese cabbage (Brassica pekinensis) used as a bait plant grown in soil of an olive orchard, was identified as Olpidium brassicae based on the size and sequence of the generated amplicon in PCR specific tests. Each of the three virus strains was soil transmitted to cabbage roots in the absence of the fungus at similar rates of 30 to 40%. Separate plant inoculation by O. brassicae zoospores incubated with each viral strain resulted in enhanced transmission of OMMV, reaching 86% of infection whereas that of the other two strains remained practically unaffected at ca. 34%. Binding assays showed that the amount of virus bound to zoospores, estimated spectrophotometrically, was 7% in the case of OMMV, and practically nil in the case of the other two viral strains. Substitution of the coat protein (CP) gene of OMMV by that of the OMMV L11 strain, drastically reduced viral transmissibility in the presence of zoospores to the level of that observed in their absence. Our data shows that OMMV soil transmission is greatly enhanced by O. brassicae zoospores and that the viral CP plays a significant role in this process, most likely by facilitating virus binding and later entrance into the host plant roots

    Safety of frozen vegetables: a case study on carrots

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    Consumers are confident in frozen foods, which is a consequence of proven safety and quality characteristics of the products. However, safety depends strongly on the quality of the raw materials, the hygienic conditions when handling both at industrial and home processing, and on the temperature conditions during the entire logistic chain. Bacteria survival depends upon a number of factors, such as type of microorganism, freezing process, rate of freezing, storage temperatures and freeze-thaw cycles. The goal of this work was to quantify the impact of the freezing operation per si and frozen storage, at two temperatures (-7º and –20 ºC), on total aerobes, yeast and moulds levels on shredded carrots (Daucus carrota L.). Results showed that, for both temperatures analyzed, the freezing operation itself had a significant effect (p<0,05) in reducing microbial counts, when compared with the initial levels. Storage temperature did not influence significantly mesophilic aerobic flora levels (p<0,05). However, yeasts counts in samples stored at –20ºC presented a gradual decline along the storage period, being significantly lower than samples at -7ºC, after 10 days of storage. Moulds were not detected in all analyzed samples

    An estimate of the total catch in the Spanish Mediterranean Sea and Gulf of Cadiz regions (1950-2010)

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    The underestimation of fisheries removals is a global issue that spans countries from different continents and different socio-economic situations. Underestimation of catches is especially important in countries where fishing fleets are highly diversified, the enforcement of fishing management is low, data availability is poor, and there is high demand for fish products in local markets. This is the case for Mediterranean countries. Here, we estimated total removals of marine resources by Spain from 1950 to 2010 for the Spanish Mediterranean Sea and Gulf of Cadiz regions following a catch-reconstruction approach. We first collected information from scientific publications, grey literature and secondary sources of information (i.e., personal communications, interviews with managers and fishers) to complement officially reported catch data, which are publicly available from FAO databases and from national and regional statistics. A literature search and fishers interviews provided assessments of missing catch sectors that are time-point estimates. These were used as anchor points of reliable data upon which we then estimated total catch using interpolation to fill in the periods for which quantitative data were missing. Overall, the reconstructed catch was 70% larger than the nationally reported data for the same time period. Results illustrated that unreported removals and discards represent important portions of total removals in the study area. Unreported landings and discards accounted for, on average, 42% of total removals between 1950s and 2010, and were composed of black market sales, subsistence fishing, artisanal fishing, recreational fishing and illegal catch, in addition to discarding. By the late 2000s, recreational fishing was the most important sector for unreported landings (~36%), followed by black market sales (~32%), subsistence fishing (~17%), unreported artisanal fishing (~12%) and illegal catch (~2%). While FAO landings data showed an increase of landings from 1950 to the mid-1960s and a decline from the mid-1970s to 2010, a different trend emerged after accounting for all fisheries removals. Reconstructed total catches revealed an earlier maximum of total removals in the late 1950s, a plateau being reached during the 1960s and 1970s, and a decline from the early 1980s to 2010. Our estimates of total fisheries catches represent an improvement over official catch data, and suggest a different historical trend of marine resource use

    Oxido-and dioxido-vanadium(V) complexes supported on carbon materials: Reusable catalysts for the oxidation of cyclohexane

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    UIDB/00100/2020 UIDB/50006/2020 UIDP/50006/2020 CEECINST/00102/2018 UIDB/50020/2020 IST-ID/102/2018 UID/QUI/00100/2019-BL/CQE-2017-022 FCTOxidovanadium(V) and dioxidovanadium(V) compounds, [VO(OEt)L] (1) and [Et3NH][VO2L] (2), were synthesized using an aroylhydrazone Schiff base (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L). They were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), (1H and51V) nuclear magnetic resonance (NMR), electrospray ioniza-tion mass spectrometry (ESI-MS) and single crystal X-ray diffraction analyses. Both complexes were immobilized on functionalized carbon nanotubes and activated carbon. The catalytic performances of 1 and 2, homogenous and anchored on the supports, were evaluated for the first time towards the MW-assisted peroxidative oxidation (with tert-butylhydroperoxide, TBHP) of cyclohexane under heterogeneous conditions. The immobilization of 1 and 2 on functionalized carbon materials improved the efficiency of catalytic oxidation and allowed the catalyst recyclability with a well-preserved catalytic activity.publishersversionpublishe

    Stellar evolution and modelling stars

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    In this chapter I give an overall description of the structure and evolution of stars of different masses, and review the main ingredients included in state-of-the-art calculations aiming at reproducing observational features. I give particular emphasis to processes where large uncertainties still exist as they have strong impact on stellar properties derived from large compilations of tracks and isochrones, and are therefore of fundamental importance in many fields of astrophysics.Comment: Lecture presented at the IVth Azores International Advanced School in Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in July 201
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