382 research outputs found

    Generating sequences and Poincar\'e series for a finite set of plane divisorial valuations

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    Let VV be a finite set of divisorial valuations centered at a 2-dimensional regular local ring RR. In this paper we study its structure by means of the semigroup of values, SVS_V, and the multi-index graded algebra defined by VV, \gr_V R. We prove that SVS_V is finitely generated and we compute its minimal set of generators following the study of reduced curve singularities. Moreover, we prove a unique decomposition theorem for the elements of the semigroup. The comparison between valuations in VV, the approximation of a reduced plane curve singularity CC by families of sets V(k)V^{(k)} of divisorial valuations, and the relationship between the value semigroup of CC and the semigroups of the sets V(k)V^{(k)}, allow us to obtain the (finite) minimal generating sequences for CC as well as for VV. We also analyze the structure of the homogeneous components of \gr_V R. The study of their dimensions allows us to relate the Poincar\'e series for VV and for a general curve CC of VV. Since the last series coincides with the Alexander polynomial of the singularity, we can deduce a formula of A'Campo type for the Poincar\'e series of VV. Moreover, the Poincar\'e series of CC could be seen as the limit of the series of V(k)V^{(k)}, k0k\ge 0

    Comparación de los hábitos de consumo de carne de conejo entre consumidores jóvenes y compradores tradicionales de Sevilla

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    Se estudiaron los hábitos de consumo de carne de conejo de 499 estudiantes universitarios y de 399 compradores en mercados tradicionales de Sevilla (España). Los estudiantes universitarios afirmaron haber probado (67,9%) y consumir actualmente (38,6%) la carne de conejo en menor proporción que los compradores tradicionales (prueban: 84,5%; consumen: 46,6%). Ambos grupos afirman que les gusta esta carne en la misma proporción (78%).Las mujeres, sobre todo jóvenes, afirmaron haber probado y que les gusta en menor proporción esta carne que en el caso de los hombres. Se reveló además un mayor hábito de consumo y preferencia por la carne de conejo de monte en comparación con la del de granja, siendo la carne de conejo de monte preferida a la del de granja por un 88,2% de los consumidores sin distinción de grupo. Se dedujo una disminución del consumo de la carne de conejo entre los jóvenes en comparación con los compradores en mercados tradicionales

    Quantitative proteomics reveals new insights into calcium-mediated resistance mechanisms in Aspergillus flavus against the antifungal protein PgAFP in cheese

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    The ability of Aspergillus flavus to produce aflatoxins in dairy products presents a potential hazard. The antifungal protein PgAFP from Penicillium chrysogenum inhibits various foodborne toxigenic fungi, including Aspergillus flavus. However, PgAFP did not inhibit A. flavus growth in cheese, which was related to the associated cation content. CaCl2 increased A. flavus permeability and prevented PgAFP-mediated inhibition in potato dextrose broth (PDB). PgAFP did not elicit any additional increase in permeability of CaCl2-incubated A. flavus. Furthermore, PgAFP did not alter metabolic capability, chitin deposition, or hyphal viability of A. flavus grown with CaCl2. Comparative proteomic analysis after PgAFP treatment of A. flavus in calcium-enriched PDB revealed increased abundance of 125 proteins, including oxidative stress-related proteins, as determined by label-free mass spectrometry (MS)-based proteomics. Seventy proteins were found at lower abundance, with most involved in metabolic pathways and biosynthesis of secondary metabolites. These changes do not support the blockage of potential PgAFP receptors in A. flavus by calcium as the main cause of the protective role. A. flavus resistance appears to be mediated by calcineurin, G-protein, and γ-glutamyltranspeptidase that combat oxidative stress and impede apoptosis. These findings could serve to design strategies to improve PgAFP activity against aflatoxigenic moulds in dairy products

    Integral field spectroscopy of selected areas of the Bright Bar and Orion-S cloud in the Orion Nebula

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    We present integral field spectroscopy of two selected zones in the Orion Nebula obtained with the Potsdam Multi-Aperture Spectrophotometer (PMAS), covering the optical spectral range from 3500 to 7200 A and with a spatial resolution of 1". The observed zones are located on the prominent Bright Bar and on the brightest area at the northeast of the Orion South cloud, both containing remarkable ionization fronts. We obtain maps of emission line fluxes and ratios, electron density and temperatures, and chemical abundances. We study the ionization structure and morphology of both fields, which ionization fronts show different inclination angles with respect to the plane of the sky. We find that the maps of electron density, O+/H+ and O/H ratios show a rather similar structure. We interpret this as produced by the strong dependence on density of the [OII] lines used to derive the O+ abundance, and that our nominal values of electron density-derived from the [SII] line ratio-may be slightly higher than the appropriate value for the O+ zone. We measure the faint recombination lines of OII in the field at the northeast of the Orion South cloud allowing us to explore the so-called abundance discrepancy problem. We find a rather constant abundance discrepancy across the field and a mean value similar to that determined in other areas of the Orion Nebula, indicating that the particular physical conditions of this ionization front do not contribute to this discrepancy.Comment: 15 pages, 10 figures. Accepted for publication in MNRA

    Sulfadiazine, sulfamethazine and sulfachloropyridazine removal using three different porous materials: Pine bark, “oak ash” and mussel shell

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    This work focuses on studying the efficacy of three different by-products to adsorb three antibiotics (sulfadiazine, SDZ; sulfamethazine, SMT; sulfachloropyridazine, SCP). These antibiotics can be considered pollutants of the environment when they reach water, as well as in cases where they are spread on soils through irrigation or contained in sewage sludge or livestock manure. In this study, batch-type adsorption/desorption experiments were performed for each of the three sulfonamides, adding 7 different concentrations of the antibiotics, going from 1 to 50 μmol L−1, and with contact time of 24 h. The results indicate that pine bark is the most efficient bioadsorbent among those studied, as it adsorbs up to 95% of the antibiotics added, while desorption is always less than 11%. However, for “oak ash” and mussel shell the adsorption is always lower than 45 and 15%, respectively, and desorption is high, reaching up to 49% from “oak ash” and up to 81% from mussel shell. Adsorption data showed good fitting to the Linear and Freundlich models, with R2 values between 0.98 and 1.00 in both cases. Kd and KF adsorption parameters showed similar values for the same sorbent materials but were much higher for pine bark than for the other two bioadsorbents. The Freundlich's n parameter showed values in the range 0.81–1.28. The highest KF values (and therefore the highest adsorption capacities) were obtained for the antibiotic SCP in pine bark. Pine bark showed the highest capacity to adsorb each of the antibiotics, increasing as a function of the concentration added. When the concentration of sulfonamide added was 50 μM, the amounts adsorbed were 780 μmol kg−1 for SDZ, 890 μmol kg−1 for SMT, and 870 μmol kg−1 for SCP. “Oak ash” and mussel shell have low adsorption capacity for all three sulfonamides, showing values always lower than 150 μmol kg−1 (oak ash) and 20 μmol kg−1 (mussel shell) when a concentration of 50 μmol L−1 of antibiotic is added. The results of this study could aid to make an appropriate management of the by-products studied, in order to facilitate their valorization and recycling in the treatment of environmental compartments polluted with sulfonamide antibiotics.Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C21Agencia Estatal de Investigación | Ref. RTI2018-099574-B-C2

    Agricultural biomass/waste as adsorbents for toxic metal decontamination of aqueous solutions

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    Toxic metals can be present in the environment, causing negative effects on the ecosystem and human health. Although several technologies have been used for decontamination purposes, biosorption is an environmentally friendly and cost-effective alternative to remove toxic metals from wastewater. Agricultural biomasses are a class of biosorbents that offer several advantages, including their low cost, availability in nature, simplicity to be obtained and used as adsorbents. This review article is focused on the use of agricultural biomass materials for the removal of toxic metal(oid)s from contaminated aqueous matrices. In addition, raw and modified forms of these biosorbents are considered as precursors for the preparation of other adsorbents like biochar. Following agricultural biomasses are discussed: i) watermelon, ii) potato, iii) cucumber, iv) peanut, v) almond, vi) walnut and hazelnut, vii) pistachio, and viii) tea waste-based biosorbents. The adsorption potential of the biomasses is exhibited under the optimum experimental conditions, and their characterization and possibility to reuse is also considered. Moreover, isotherm and equilibrium parameters of the metal(oid) adsorption by the biomasses are discussed. Specifically, thermodynamic studies are described in order to better understand the nature of the biosorption process between contaminant and biomass. All these considerations reflect the high potential of agricultural waste-based adsorbents for toxic metal(oid)s removal related to wastewater treatment technologies.Fil: Anastopoulos, Ioannis. University Of Cyprus; ChipreFil: Pashalidis, Ioannis. University Of Cyprus; ChipreFil: Hosseini Bandegharaei, Ahmad. Sabzevar University Of Medical Sciences; Irán. Islamic Azad University; IránFil: Giannakoudakis, Dimitrios A.. Polish Academy of Sciences; PoloniaFil: Robalds, Artis. Animal Health And Environment Bior; LetoniaFil: Usman, Muhammad. University Of Agriculture; PakistánFil: Escudero, Leticia Belén. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Zhou, Yaoyu. Hunan Agricultural University; ChinaFil: Colmenares, Juan Carlos. Polish Academy of Sciences; PoloniaFil: Núñez Delgado, Avelino. Universidad de Santiago de Compostela; EspañaFil: Lima, Éder Claudio. Universidade Federal do Rio Grande do Sul; Brasi

    Similarities between the lipid proile of Mexican patients with lupus and the general population

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    Premature cardiovascular events have been observed in systemic lupus erythematosus (SLE) patients, but the reason for this accelerated process is still debatable; although traditional risk factors are more prevalent in such patients than in the general population, the do not seem to fully explain that enhanced risk. One of the most important conditions is a proatherogenic lipid proile. There is not enough data about it in Mexican SLE patients. Objective: To establish the differences in the lipid proiles between Mexican patients with SLE and the general population. Material and methods: Observational, transversal, descriptive and comparative study, between SLE patients and age-sex-matched healthy volunteers. We performed a full lipid proile (by spectrophotometry) 14 hours of fast. The results obtained were analyzed by the statistical program SPSS® Statistics version 17. Results: We studied the full lipid proiles of 138 subjects, 69 with a diagnosis of SLE and 69 agesex- matched healthy volunteers; 95.7% were females and 4.3% males. Average age was 30 years; average body mass index (BMI) 25.96 ± 5.96 kg/m² in SLE patients and 26.72 ± 4.36 kg/m² in the control group (p = 0.396). Average of total cholesterol 156 mg/dl in the SLE patients and 169.4 mg/dl in the control group (p =0.028); average of low density lipoprotein (LDL) cholesterol 85.27 mg/dl in the SLE patients and 97.57 mg/dl in the control group (p = 0.023). Conclusions: We did not ind statistical differences in the lipid proiles among patients and healthy volunteers, which could explain increased cardiovascular morbidity and mortality observed in SLE patient
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