12,533 research outputs found

    A near-IR line of Mn I as a diagnostic tool of the average magnetic energy in the solar photosphere

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    We report on spectropolarimetric observations of a near-IR line of Mn I located at 15262.702 A whose intensity and polarization profiles are very sensitive to the presence of hyperfine structure. A theoretical investigation of the magnetic sensitivity of this line to the magnetic field uncovers several interesting properties. The most important one is that the presence of strong Paschen-Back perturbations due to the hyperfine structure produces an intensity line profile whose shape changes according to the absolute value of the magnetic field strength. A line ratio technique is developed from the intrinsic variations of the line profile. This line ratio technique is applied to spectropolarimetric observations of the quiet solar photosphere in order to explore the probability distribution function of the magnetic field strength. Particular attention is given to the quietest area of the observed field of view, which was encircled by an enhanced network region. A detailed theoretical investigation shows that the inferred distribution yields information on the average magnetic field strength and the spatial scale at which the magnetic field is organized. A first estimation gives ~250 G for the mean field strength and a tentative value of ~0.45" for the spatial scale at which the observed magnetic field is horizontally organized.Comment: 42 pages, 17 figures, accepted for publication in the Astrophysical Journal. Figures 1 and 9 are in JPG forma

    Analytical study on ethephon residue determination in water by ion-pairing liquid chromatography/tandem mass spectrometry

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    A detailed analytical study on ethephon residue determination in water, making use of ion-pairing liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS), has been carried out. Ethephon is a plant growth regulator, highly polar, which is typically present in aqueous solution in anionic form due to its acid character. Both its extraction and pre-concentration from water samples and its chromatographic retention are difficult. Several approaches for sample pretreatment have been tested including direct injection into the chromatographic system, on-line solid phase extraction (SPE) and off-line SPE, with the best results being obtained after off-line SPE, using Oasis MAX cartridges (mixed-mode strong anion-exchange). After testing several ion-pairing reagents, tetrabuthylammonium acetate (TBA) was selected. This was added to the samples before LC/MS/MS analysis to facilitate ethephon chromatographic retention. The acquisition of several specific MS/MS transitions together with the evaluation of their relative intensity ratios allowed the reliable confirmation of the analyte in samples. The optimised approach was tested in low-salinity water spiked at 0.1 µg L−1 level with satisfactory recovery, and a limit of detection of 0.02 µg L−1. To this purpose, the water sample was partially de-ionised in an initial stage, in order to remove major ions that would have interfered in analyses. The application of this methodology to more saline/complex water samples, as surface or wastewater, was problematic and a thorough optimisation of the de-ionisation conditions would be required

    Pesticide residues and transformation products in groundwater from a Spanish agricultural region on the Mediterranean Coast

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    An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TP

    On the solution of a supersymmetric model of correlated electrons

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    We consider the exact solution of a model of correlated electrons based on the superalgebra Osp(2∣2)Osp(2|2). The corresponding Bethe ansatz equations have an interesting form. We derive an expression for the ground state energy at half filling. We also present the eigenvalue of the transfer matrix commuting with the Hamiltonian.Comment: Palin latex , 8 page

    Development of Tropical Spastic Paraparesis in Human T-Lymphotropic Virus Type 1 Carriers Is Influenced by Interleukin 28B Gene Polymorphisms

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    Producción CientíficaInterleukin 28B (IL28B) rs12979860 polymorphisms were examined in 41 individuals with human T-lymphotrophic virus type 1 (HTLV-1). The alleles CT/TT were more frequent in 12 individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis than in 29 asymptomatic carriers (80% vs 20%; P = .03), and median HTLV-1 proviral load was greater in CT/TT than CC carriers (P = .01). Thus, IL28B testing and closer follow-up of HTLV-1 asymptomatic CT/TT carriers is warranted.Fundación Investigación y Educación en Sida Grant (IES) FIS (CP05/00300)Red de Investigación en SIDA Grant (RIS, ISCIII-RETIC RD06/006)Proyecto europeo NEAT Grant (LSHP-CT-2006-037570

    Safety of the feed additive consisting of manganese chelates of lysine and glutamic acid for all animal species (Zinpro Animal Nutrition)

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    Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety for target animals of manganese chelates of lysine and glutamic acid (Manganese-LG) as a nutritional feed additive for all animal species. The European Commission request followed an opinion of the FEEDAP Panel published in 2020; in that opinion, the FEEDAP Panel could conclude on the safety of the additive for chickens for fattening, but not for the rest of the target animals. The applicant submitted additional information to allow the FEEDAP Panel to complete its assessment; these additional data, comprising two tolerance studies (one with chickens for fattening and one with laying hens), were the subject of this opinion. The tolerance study in laying hens was not considered for the assessment since the housing conditions of the animals were not appropriate according to the relevant EU provisions. The results of the tolerance study in chickens for fattening showed that Manganese-LG at the highest level tested – 800 mg Mn/kg feed – is safe for these target animals. The FEEDAP Panel also considered a previous tolerance study in chickens for fattening. Taking all the evidence together the Panel concluded that Manganese-LG is safe for chickens for fattening at 150 mg Mn/kg feed, with a margin of safety of 5.5. This conclusion can be extrapolated to all animal species and categories provided that the maximum authorised levels in the EU for total manganese in feed are not exceeded

    Safety and efficacy of copper chelates of lysine and glutamic acid as a feed additive for all animal species

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    Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of copper chelates of lysine and glutamic acid (Copper-LG) as a nutritional feed additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concludes that, owing to safety considerations, Copper-LG should not be used in water for drinking. Copper-LG is safe for chickens for fattening; this conclusion can be extrapolated to all animal species and categories provided that the maximum authorised levels in the EU for total copper in feed are not exceeded. No increases in the copper content of animal tissues/products are expected from the use of Copper-LG in animal nutrition. There is no indication that the toxicity of Copper-LG is essentially different from that of inorganic divalent copper. The use of Copper-LG in animal nutrition is of no concern for consumer safety provided that the maximum authorised total copper in feed is respected. Owing to the copper and nickel content of Copper-LG, the handling of the additive, poses a risk to users by inhalation. The additive is considered as a skin and respiratory sensitiser; it is corrosive to the eye while it is non-irritant to skin. The additive is intended to be a substitute for other authorised copper additives and will not further increase the environmental burden of copper; therefore, the FEEDAP Panel considers that the use of the additive in animal nutrition would not pose an additional risk for the environment. Copper-LG is a bioavailable source of copper, comparable to the standard inorganic copper source, and therefore, the additive is efficacious in meeting the birds copper requirements; this conclusion can be extrapolated to all animal species/categories. The FEEDAP Panel posed a recommendation concerning the description of the additive

    Standardised inventories of spiders (Arachnida, Araneae) on touristic trails of the native forests of the Azores (Portugal)

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    Background The sharp increase in tourist visitation of the Azores Archipelago from 2015 onwards raised concerns about the impacts of recreational tourism on native habitats. In response, a project was financed by the Azorean Government to investigate the drivers of biodiversity erosion associated with recreational tourism. Here, we present the data on spider biodiversity found on trails located within the native Azorean forests as they are home to several endemic species of great conservation value. We applied an optimised and standardised sampling protocol (COBRA) in twenty-three plots located in five trails on Terceira and Sao Miguel Islands and assessed diversity and abundance of spider species at different distances from the trail head and the trail itself. New information Of the 45 species (12435 specimens) collected, 13 were endemic to the Azores (9690 specimens), 10 native non-endemic (2047 specimens) and 22 introduced (698 specimens). This database will be the baseline of a long-term monitoring project for the assessment of touristic impacts on native forest trails. This methodology can also be used on other habitats and biogeograhical regions.Peer reviewe

    Assessment of the application for renewal of authorisation of GalliPro ® (Bacillus subtilis DSM 17299) for chickens for fattening

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    GalliPro \uae is the trade name for a feed additive based on viable cells of a strain of Bacillus subtilis intended for use as a zootechnical additive (gut flora stabiliser) in feed for chickens for fattening. The product is currently authorised for use in chickens for fattening. This opinion concerns the renewal of this authorisation. Bacillus subtilis is considered by EFSA to be suitable for the qualified presumption of safety (QPS) approach to establish the safety for the target species, consumers and the environment. The identity of the strain present in the additive was established and evidence was provided on the lack of toxigenic potential as well as acquired antibiotic resistance determinants to antibiotics of human and veterinary importance. Accordingly, this strain is presumed safe for the target species, consumers of products derived from animals fed the additive and the environment. Since no concerns are expected from other components of the additive, GalliPro \uae is considered safe for the target species, consumers and the environment. The applicant has provided evidence that the additive currently in the market complies with the existing conditions of authorisation. The FEEDAP Panel confirms its previous conclusions that GalliPro \uae is safe for the target species; consumers of products from animals fed the additive and the environment. GalliPro \uae should be considered a potential respiratory sensitiser. In the absence of data, the FEEDAP Panel cannot conclude on the potential of GalliPro \uae for skin and eyes irritancy and dermal sensitisation

    Safety and efficacy of Biomin \uae DC-C as a zootechnical feed additive for weaned piglets

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    The additive (trade name Biomin \uae DC-C) is a blend of essential oils from oregano (Origanum vulgare L.) and from caraway seed (Carum carvi L.) and three individual compounds (carvacrol, methyl salicylate and l-menthol) encapsulated with a hydrogenated vegetable oil. The additive is intended for use in feed for weaned piglets at a minimum concentration of 75 mg/kg complete feed and a recommended maximum level of 125 mg/kg complete feed. A tolerance test in which piglets were exposed to feed containing up to an intended 1,250 mg additive/kg complete feed showed that additive is safe for piglets at the maximum recommended level with at least a sixfold margin of safety. The active components of the additive are not genotoxic and from the available residue study, based on the detection of five marker compounds, no measurable exposure of the consumers is foreseen; consequently, the use of the additive is considered safe for consumers of animal products. The FEEDAP Panel considered that exposure to users by inhalation is unlikely; in the absence of data, the Panel cannot conclude on the effects of Biomin \uae DC-C on skin and eyes. The use of the additive in animal production is not expected to pose a risk for the terrestrial or aquatic environments. Based on the results of three efficacy studies in which positive benefits were seen, the additive has a potential to improve the growth performance of weaned piglets at a minimum application rate of 75 mg/kg complete feed
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