11,749 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,

    Is emamectin benzoate effective against the different stages of Spodoptera exigua (Hübner) (Lepidoptera, Noctuidae)?

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    peer-reviewedThis work was partially supported by the Spanish Ministry of Science and Innovation (project AGL 2007-66130-C03-02 to P. Medina). F. Amor and P. Bengochea acknowledge the ministry of Education and Culture and the Technical University of Madrid (UPM) for the doctoral fellowships. Special thanks to Syngenta Agro S.A. for their support.The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera, Noctuidae), is a major polyphagous pest in greenhouses and open fields worldwide and also a main problem in sweet pepper greenhouses. The effectiveness of the pesticide emamectin benzoate was tested in the laboratory on different stages of S. exigua using different concentrations and uptake routes. After dipping young (48-h-old) S. exigua eggs in emamectin benzoate at 0.5, 1 and 1.5 mg/L a.i. the chemical did not exhibit any ovicidal activity. There was, however, progressive neonate mortality at all concentrations, culminating at 72 hours after hatching, when 100% of the larvae from the treated young eggs died. Second and fourth instar S. exigua larvae did not exhibit significant mortality when exposed to the inert surfaces which were treated. In contrast, ingesting a diet contaminated with 0.5 mg/L a.i. of emamectin benzoate caused 100% mortality in L2 and L4 larvae 24 and 72 hours after ingestion, respectively. The LC50 value of the compound against L4 larvae that fed on sprayed sweet pepper leaves for 24 hours was 0.81 mg/L a.i.. When adults were fed on a solution of 0.5 mg/L a.i., there was a reduction in the female and male lifespan of 29.3% and 55.3%, respectively. Fecundity was reduced by more than 99%. These data suggest that emamectin benzoate is not only a useful insecticide when ingested by beet armyworm larvae but it also has ovolarvicidal and adult activity.Spanish Ministry of Science and Innovatio

    On the difference of torus geometry between hidden and non-hidden broad line active galactic nuclei

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    We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy torus models. We compiled high spatial resolution (0.3\sim 0.3--0.70.7 arcsec) mid-IR NN-band spectroscopy, QQ-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy torus models, enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus model parameters gives us the first quantitative torus geometrical view for each subgroup. We find that NHBLR AGN have smaller torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small torus opening angle and (b) the increased torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.Comment: 13 pages, 5 figures, accepted for publication in Ap

    Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

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    We present sub-arcsecond 7.5-13 μ\mum imaging- and spectro-polarimetric observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio CANARIAS. At all wavelengths, we find: (1) A 90 ×\times 60 pc extended polarized feature in the northern ionization cone, with a uniform \sim44^{\circ} polarization angle. Its polarization arises from dust and gas emission in the ionization cone, heated by the active nucleus and jet, and further extinguished by aligned dust grains in the host galaxy. The polarization spectrum of the jet-molecular cloud interaction at \sim24 pc from the core is highly polarized, and does not show a silicate feature, suggesting that the dust grains are different from those in the interstellar medium. (2) A southern polarized feature at \sim9.6 pc from the core. Its polarization arises from a dust emission component extinguished by a large concentration of dust in the galaxy disc. We cannot distinguish between dust emission from magnetically aligned dust grains directly heated by the jet close to the core, and aligned dust grains in the dusty obscuring material surrounding the central engine. Silicate-like grains reproduce the polarized dust emission in this feature, suggesting different dust compositions in both ionization cones. (3) An upper limit of polarization degree of 0.3 per cent in the core. Based on our polarization model, the expected polarization of the obscuring dusty material is \lesssim0.1 per cent in the 8-13 μ\mum wavelength range. This low polarization may be arising from the passage of radiation through aligned dust grains in the shielded edges of the clumps.Comment: 17 pages, 10 figures, accepted for publication at MNRA

    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(22)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

    Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind

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    We present J' and K' imaging linear polarimetric adaptive optics observations of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5" (30 pc) aperture at K', we find that polarisation arising from the passage of radiation from the inner edge of the torus through magnetically aligned dust grains in the clumps is the dominant polarisation mechanism, with an intrinsic polarisation of 7.0%±\pm2.2%. This result yields a torus magnetic field strength in the range of 4-82 mG through paramagnetic alignment, and 13920+11^{+11}_{-20} mG through the Chandrasekhar-Fermi method. The measured position angle (P.A.) of polarisation at K' is found to be similar to the P.A. of the obscuring dusty component at few parsec scales using infrared interferometric techniques. We show that the constant component of the magnetic field is responsible for the alignment of the dust grains, and aligned with the torus axis onto the plane of the sky. Adopting this magnetic field configuration and the physical conditions of the clumps in the MHD outflow wind model, we estimate a mass outflow rate \le0.17 M_{\odot} yr1^{-1} at 0.4 pc from the central engine for those clumps showing near-infrared dichroism. The models used were able to create the torus in a timescale of \geq105^{5} yr with a rotational velocity of \leq1228 km s1^{-1} at 0.4 pc. We conclude that the evolution, morphology and kinematics of the torus in NGC 1068 can be explained within a MHD framework.Comment: 14 pages, 4 figures, Accepted by MNRA

    Spectrophotometric Study of Polymeric DyesGels After a Gamma Irradiation Process for its Possible Use as a Radiation Dosimeter

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    This work aims to evaluate a dosimetric system composed of green malachite supported in agarose. Previous work showed that solutions of green malachite irradiated at 1 to 40 kGy present a linear behavior. This system is a gel composed of green malachite (2.5×10–3 M), sodium benzoate (1%),and agarose (1%) that was exposed tovarious doses of gamma irradiation. The irradiated systems were measured with a UV-V is spectrophotometer at 619 nm. Experimental parameters (such as dose rate, doses, and temperature) were controlled and optimized for reproducible and reliable results. More studies are needed to propose a dosimeter in the system in the range of 1.8 to 4.0 kGy

    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
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