11,344 research outputs found

    Conformación de la agroindustria del amaranto en Santiago Tulyehualco, Xochimilco, México. Elementos que han permitido la transformación productiva y social en las familias rurales.

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    El presente trabajo versa sobre el desarrollo de la agroindustria del amaranto al sur del Distrito Federal, Ciudad de México. Esta actividad, además de ser de gran importancia económica para la localidad y comunidades vecinas, ya que en ella participan familias enteras, da un elevado sentido de pertenencia y cohesión entre los habitantes. La actividad agroindustrial consta de cuatro procesos: producción primaria, acopio, transformación y comercialización. Las familias amaranteras, que participan en este trabajo, participan en toda la cadena de valor desde hace varias generaciones. El eje de análisis se refiere a los factores que permiten la transformación en estructura y funcionamiento de la unidad de producción campesina hacia unidades agroindustriales. El enfoque que se utilizará para entender los procesos de cambio que se han dado en las unidades de producción rural y que permiten el desarrollo, evolución y consolidación de las estrategias se basa en el modelo de Organizaciones Productivas Familiares Rurales [1]. Dicho modelo separa tres ámbitos presentes e interrelacionados siempre presentes en las unidades: la propiedad, la familia y la actividad productiva agropecuaria. Este modelo nos ofrece argumentos de gran utilidad para entender los procesos de cambio que se gestan en las unidades campesinas, en su transito hacia la nueva cultura empresarial. Para la colección de información se recurrió a la aplicación de entrevistas, estructuradas, semi-estructuradas e historias de vida. Entre los principales hallazgos se puede mencionar: a) el nivel de desarrollo de la unidad de producción está relacionada con el momento en que se encuentre la familia dentro de su ciclo de desarrollo, b) las características personales del matrimonio propietario son determinantes para el cambio productivo implícito en el avance de la unidad y c) el entendimiento de las familias sobre sus necesidades, y la capacidad de gestión y negociación de sus representantes permiten el acceso a recursos que coadyuvan al cambio productivo. La principal conclusión es que el grado de avance de las unidades de producción, está en función del balance logrado por las familias operadoras entre intereses /necesidades y recursos /capacidades.Agroindustria, familia rural., Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Labor and Human Capital,

    New Latin American Perspectives on Sustainable and Low Carbon Societies

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    The interaction of aluminum with catecholamine-based neurotransmitters: Can the formation of these species be considered a potential risk factor for neurodegenerative diseases?

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    The potential neurotoxic role of Al(iii) and its proposed link with the insurgence of Alzheimer's Disease (AD) have attracted increasing interest towards the determination of the nature of bioligands that are propitious to interact with aluminum. Among them, catecholamine-based neurotransmitters have been proposed to be sensitive to the presence of this non-essential metal ion in the brain. In the present work, we characterize several aluminum-catecholamine complexes in various stoichiometries, determining their structure and thermodynamics of formation. For this purpose, we apply a recently validated computational protocol with results that show a remarkably good agreement with the available experimental data. In particular, we employ Density Functional Theory (DFT) in conjunction with continuum solvation models to calculate complexation energies of aluminum for a set of four important catecholamines: l-DOPA, dopamine, noradrenaline and adrenaline. In addition, by means of the Quantum Theory of Atoms in Molecules (QTAIM) and Energy Decomposition Analysis (EDA) we assessed the nature of the Al-ligand interactions, finding mainly ionic bonds with an important degree of covalent character. Our results point at the possibility of the formation of aluminum-catecholamine complexes with favorable formation energies, even when proton/aluminum competition is taken into account. Indeed, we found that these catecholamines are better aluminum binders than catechol at physiological pH, because of the electron withdrawing effect of the positively-charged amine that decreases their deprotonation penalty with respect to catechol. However, overall, our results show that, in an open biological environment, the formation of Al-catecholamine complexes is not thermodynamically competitive when compared with the formation of other aluminum species in solution such as Al-hydroxide, or when considering other endogenous/exogenous Al(iii) ligands such as citrate, deferiprone and EDTA. In summary, we rule out the possibility, suggested by some authors, that the formation of Al-catecholamine complexes in solution might be behind some of the toxic roles attributed to aluminum in the brain. An up-to-date view of the catecholamine biosynthesis pathway with sites of aluminum interference (according to the current literature) is presented. Alternative mechanisms that might explain the deleterious effects of this metal on the catecholamine route are thoroughly discussed, and new hypotheses that should be investigated in future are proposed

    Time-Dependent Behavior of Linear Polarization in Unresolved Photospheres, With Applications for The Hanle Effect

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    Aims: This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line polarization, and use geometric arguments to generalize these results to linear polarization due to other mechanisms. Methods: Building on the work of Lopez Ariste et al., we use simple analytic models of rotating stars that are symmetric except for an axisymmetric magnetic field to predict the polarization lightcurve due to the Hanle effect. We highlight the effects for the variable line polarization as a function of viewing inclination and field axis obliquity. Finally, we use geometric arguments to generalize our results to linear polarization from the weak transverse Zeeman effect. Results: We derive analytic expressions to demonstrate that the variable polarization lightcurve for an oblique magnetic rotator is symmetric. This holds for any axisymmetric field distribution and arbitrary viewing inclination to the rotation axis. Conclusions: For the situation under consideration, the amplitude of the polarization variation is set by the Hanle effect, but the shape of the variation in polarization with phase depends largely on geometrical projection effects. Our work generalizes the applicability of results described in Lopez Ariste et al., inasmuch as the assumptions of a spherical star and an axisymmetric field are true, and provides a strategy for separating the effects of perspective from the Hanle effect itself for interpreting polarimetric lightcurves.Comment: 6 pages; 4 figures. Includes an extra figure found only in this preprint versio

    Safety and efficacy of Taminizer D (dimethylglycine sodium salt) as a feed additive for chickens for fattening

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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 Taminizer D (dimethylglycine sodium salt) as a feed additive for chickens for fattening, based on a dossier submitted for the modification of the terms of authorisation of the additive. The product is authorised in the European Union for chickens for fattening at the maximum content of 1,000 mg/kg complete feedingstuffs. The applicant proposed the introduction of an additional manufacturing process, which introduces an impurity (dimethylamino-ethanol (DMAE)) in the additive at concentrations up to 0.09%. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considered that the proposed modification would not substantially affect the previous assessment as related to the safety of the environment and the efficacy of the product. Since the safety of the active substance was established, the current assessment has dealt with the impurity DMAE. Considering the toxicological profile of DMAE, the estimated intake by the target animal and consumers, and making use of the Threshold of Toxicological Concern (TTC) approach, the Panel concluded that Taminizer D, manufactured by the DMAE route, is safe for both chickens for fattening and consumers, up to the maximum level of 1,000 mg/kg feed. The FEEDAP Panel extends its conclusions about Taminizer D produced by the original method to cover also Taminizer D produced by the new DMAE method. There is minimal risk to users from dust produced as a result of normal handling of the additive. Taminizer D is not irritant to skin but may be irritant to eyes; it is regarded as a potential skin sensitiser. The FEEDAP Panel recommended to set a specification for the DMAE content in the additive

    Safety and efficacy of Kelforce \uae (l-glutamic acid, N,N-diacetic acid, tetrasodium salt (GLDA-Na 4 )) as a feed additive for chickens for fattening

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    l-Glutamic acid, N,N-diacetic acid, tetrasodium salt (GLDA-Na 4 ) (Kelforce \uae ) is sought to be used as a zootechnical feed additive in chickens for fattening to improve the absorption of zinc from feed, reducing zinc emissions through manure and thus, affecting favourably the environment. The product has not been authorised in the European Union as a feed additive. Kelforce \uae is intended to be marketed as a liquid and solid formulation, containing 65 47% and 65 30% of GLDA-Na 4 , respectively. Kelforce \uae is safe for chickens for fattening at the maximum level of 1,000 mg GLDA-Na 4 /kg complete feed. Based on the toxicological profile of GLDA-Na 4 and the consumer exposure to GLDA-Na 4 and to nitrilotriacetic acid trisodium salt (NTA-Na 3 ; an impurity of the additive), the use of Kelforce \uae at the maximum proposed level in feed of chickens for fattening is of no concern for consumer safety. Due to its low inhalation toxicity, the exposure to GLDA-Na 4 is unlikely to pose a risk by inhalation. However, owing to the high-dusting potential of the solid formulation, a risk from such high level of dust, even if toxicologically inert, cannot be excluded. Kelforce \uae is not a skin/eye irritant or skin sensitiser. No risks for the terrestrial compartment were identified at the maximum use level of the additive. Risks for the aquatic compartment cannot be excluded based on the secondary effect of the additive on green algae. In the absence of data, the Panel cannot conclude on the safety for the sediment compartment or the possible ground water contamination. The risk of bioaccumulation and secondary poisoning caused by the additive is considered very low. Owing to the inconsistent and conflicting results from the studies assessed, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) cannot conclude on the efficacy of the additive. The Panel made a recommendation regarding the levels of formaldehyde and cyanide in the active substance

    Safety and efficacy of fumonisin esterase from Komagataella phaffii DSM 32159 as a technological feed additive for pigs and poultry

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    Fumonisin esterase produced from a genetically modified strain of Komagataella phaffi is intended to degrade fumonisin mycotoxins contaminants in feeds for pigs and poultry. The production strain and its recombinant genes are not present in the final product. The applicant selected 300 U/kg feed to represent a likely upper limit. This concentration showed to be safe for piglets, chickens and turkeys for fattening and laying hens; the additive is thus safe for those categories. This conclusion is extended to all pigs, chickens reared for laying and turkeys reared for breeding and extrapolated to all other poultry species for growing and laying and to minor porcine species. No evidence of mutagenicity or genotoxicity was detected and no evidence of toxicity from a repeated-dose oral toxicity study; the residue assessment did not identify any concern. The use of the additive is, thus, considered safe for consumers. The additive is not toxic by inhalation and the respiratory exposure is likely to be low; however, a risk of sensitisation via the respiratory route cannot be excluded. The additive is non-irritant to skin and eyes and is not considered a dermal sensitiser. No risks for the environment are expected following the use of the additive in feeds under the proposed condition of use. The additive has the capacity to degrade fumonisin contaminants in feed of marketable quality when used at the minimum recommended dose of 10 U/kg complete feed, as shown in studies with chickens for fattening, laying hens and weaned piglets. Since the mode of action of the additive can be reasonably assumed to be the same in animal species for which the application is made, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers the additive efficacious for all poultry and all pigs

    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 benzoic acid for pigs and poultry

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    The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked by the European Commission to deliver a scientific opinion on the safety and efficacy of benzoic acid as feed flavouring for piglets (suckling, weaned), pigs for fattening, sows (for reproduction, in order to have benefit in piglets), minor porcine species, chickens (for fattening, reared for laying), hens (laying, breeding), turkeys (for fattening, for breeding purposes, reared for breeding) and minor poultry species. Benzoic acid is safe for weaned piglets at 2,500 mg/kg feed, and for laying hens, turkeys and chickens for fattening at 500 mg/kg feed; no conclusions could be drawn for suckling piglets and sows. The conclusions on weaned piglets can be extended to pigs for fattening and extrapolated to growing minor porcine species. The conclusions on chickens/turkeys for fattening can be extended to chickens reared for laying and turkeys reared for breeding and extrapolated to minor poultry species up to the point of lay. In the absence of safety margin in laying hens, no conclusions can be reached for minor poultry species for laying/breeding. The use of the additive is not expected to pose a risk to consumer, considering that the additive is rapidly metabolised with very low deposition, if any, in edible tissues of pigs and poultry and that foods of animal origin provide a very minor contribution, if any, to the overall dietary intake of benzoic acid. Owing to the unlikelihood of exposure, no risk to users upon inhalation of the additive is expected; the additive is not a skin sensitiser, but is a skin/ eye irritant. The proposed use of the additive does not pose environmental risks. Benzoic acid is authorised as food flavouring and its function in feed is essentially the same; no further demonstration of efficacy is necessary
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