Comparación de Ocho Materiales Genéticos de Maíz (Zea mays L.) en la Región de Santa Marta

Este estudio fue realizado en la Granja Agropecuaria del Servicio Nacional de Aprendizaje (SENA), ubicada en el corregimiento de Gaira, municipio de Santa Marta a una altura de 7 m.s.n.m con una temperatura promedia de 32°C y una humedad relativa comprendida entre 70 y 74.3 %, con una precipitación promedia anual de 880 mm. El trabajo se llevó a cabo en el segundo semestre de 1985, utilizando los siguientes materiales: el Gran Amarillo como material testigo, el híbrido ICA 11-211, el material básico MB-126 y las variedades ICA V-156, ICA V-155, ICA V-109, ICA V-106 y DV-206. Los objetivos planteados para desarrollar éste trabajo fueron: 1. Estudiar las fases fonológicas y características en los distintos materiales de maíz. 2: Identificar cuales se adaptan mejor a nuestra zona. 3: Determinar el rendimiento de los ocho (8) materiales de maíces. El trabajo fue realizado en un suelo de textura franco-arenosa, estructura granulosa, con un color pardo cenizo, utilizando un diseño experimental de bloques al azar, de cuatro (4) replicaciones y ocho (8) tratamientos por replicación, las parcelas utilizadas tenían cada una las siguientes medidas: 10 m de largo por 6 m de ancho para un área de 60 m2. Cada parcela costaba de seis (6) surcos sembrados a una distancia entre plantas de 0.30 m y entre surcos o hilera de un (1) m, al momento del raleo se dejó una planta por sitio. Se cosecharon los cuatro (4) surcos centrales de cada parcela (área parcela experimental = 40 m2. Una vez hecho los estudios del rendimiento para cada material, se encontró que los materiales más rendidores fueron: ICA V-155, ICA V156, con 5.209,3 Kg/Ha, seguido por ICA V-109, ICA V-106, que tuvieron un rendimiento de 5.143,75 y 4.944,3 Kg/Ha respectivamente. Los demás materiales tuvieron rendimientos aceptables. El análisis estadístico demostró que hubo diferencia altamente significativa entre los materiales. Para la obtención de éstos resultados se hicieron análisis de varianza y prueba de Duncan para los parámetros, rendimientos, altura de la planta, altura de la mazorca superior, altura de la mazorca inferior. Los maíces de mayor rentabilidad fueron: ICA V-155, ICA V-156, seguido de ICA V-109 y el ICA V-106, los materiales restantes tuvieron una rentabilidad aceptable. Para mostrar los resultados de la prueba regional se realizó un día de campo, con el fin de mostrarle a los agricultores, campesinos y demás asistentes, las características de cada uno de los materiales mejorados en comparación con el testigo (Gran Amarillo), maíz sembrado tradicionalmente en la zona. Se contó con una asistencia muy nutrida

Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires

A straightforward method for the synthesis of CoFe2.7/CoFe2O4 core/shell nanowires is described. The proposed method starts with a conventional pulsed electrodeposition procedure on alumina nanoporous template. The obtained CoFe2.7 nanowires are released from the template and allowed to oxidize at room conditions over several weeks. The effects of partial oxidation on the structural and magnetic properties were studied by x-ray spectrometry, magnetometry, and scanning and transmission electron microscopy. The results indicate that the final nanowires are composed of 5 nm iron-cobalt alloy nanoparticles. Releasing the nanowires at room conditions promoted surface oxidation of the nanoparticles and created a CoFe2O4 shell spinel-like structure. The shell avoids internal oxidation and promotes the formation of bi-magnetic soft/hard magnetic core/shell nanowires. The magnetic properties of both the initial single-phase CoFe2.7 nanowires and the final core/shell nanowires, reveal that the changes in the properties from the array are due to the oxidation more than effects associated with released processes (disorder and agglomeration).Fil: Londoño Calderon, Cesar Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Moscoso Londoño, Oscar. Universidade Estadual de Campinas; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Muraca, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidade Estadual de Campinas; Brasil. Brazilian Center for Research in Energy and Materials. Brazilian Nanotechnology National Laboratory; BrasilFil: Arzuza, Luis. Universidade Estadual de Campinas; BrasilFil: Carvalho, Peterson. Universidade Estadual de Campinas; BrasilFil: Pirota, Kleber Roberto. Universidade Estadual de Campinas; BrasilFil: Knobel, Marcelo. Universidade Estadual de Campinas; BrasilFil: Pampillo, Laura Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Martinez Garcia, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Formosa. Facultad de Recursos Naturales; Argentin

Effect of gallium and vanadium in NiMoV/Al2O3-Ga2O3 catalysts on indole hydrodenitrogenation

The effect of Ga as support modifier and V as second promoter on the NiMoV/Al2O3-Ga2O3 catalyst varying the synthesis method (SG: sol–gel synthesis vs I: impregnation synthesis) was studied. The catalysts were characterized by elemental analysis, textural properties, XRD, XPS, 27Al NMR, Raman, EDX elemental mapping and HRTEM. The chemical analyses by XRF showed coincidence between experimental and theoretical values according to stoichiometric values proposed to Mo/Ni = 6 and (V + Ni)/(V + Ni + Mo) = 0.35. The sol–gel synthesis method increased the surface area by incorporation of Ga3+ ions into the Al2O3 forming Ga–O–Al bonding; whereas the impregnation synthesis leads to decrease by blocking of alumina pores, as follows NiMoV/Al2O3-Ga2O3(I) < NiMoV/Al2O3-Ga2O3(SG) < Al2O3-Ga2O3(I) < NiMo/Al2O3 < Al2O3-Ga2O3(SG) < Al2O3. The values of BJH mesopores mean size between 6.13 and 7.68 nm. XRD and XPS confirmed a bulk structure typical of (NH4)4[NiMo6O24H6]·5H2O and the presence at the surface of Mo4+, Mo6+, NixSy, NiMoS, Ni2+, Ga3+ and V5+ species, respectively. Raman showed that the sol–gel synthesis method reduces the interactions Ni-Mo sulfide-support and improvement the sulfidation degree NiMoV/Al2O3-Ga2O3(SG) as showed sulfur analysis CHONS. The largest proportion of AlO4 content using the impregnation method to add Ga was verified by 27Al solid-state MAS NMR. The EDS elemental mapping confirmed that Ni, Mo, Al, Ga, V and S are well-distributed on support. The HRTEM analysis shows that the length and stacking distribution of MoS2 crystallites varied from 5.67 to 6.01 nm and 2.46 to 2.74 when using the sol–gel and impregnation synthesis method, respectively. The catalytic results revealed that the synthesis method induced the presence of gallium on the surface influencing the dispersion V5+ species, whose effect could have some relation with strength and density of acid sites that in turn influence the dispersion of the MoS2 phase, which correlates well with the indole HDN activities. The activities as indole HDN pseudo-first-order rate constants’ values (kHDN) from 0.29 to 2.78 mol/(m2·h): NiMoV/Al2O3 < NiMoV/Al2O3-Ga2O3(I) < NiMo/Al2O3 < NiMoV/Al2O3-Ga2O3(SG). Nevertheless, the nature of the active site can be related with reaction pathways, that is, NiMoV/Al2O3-Ga2O3(SG) and NiMoV/Al2O3-Ga2O3(I) catalysts produce ECH through HIND, while NiMoV/Al2O3 and NiMo/Al2O3 produce EB by hydrogenolysis of HIND to OEA. In the regard, the Ga and V act as structural promoters in the NiMo catalysts, allowing the largest generation of NiMoS M-edge-like and BRIM sites for HDN

Domain wall propagation tuning in magnetic nanowires through geometric modulation

The magnetic behavior of nickel modulated nanowires embedded in porous alumina membranes is investigated. Their diameters exhibit a sharp transition between below (35 nm) and above (52 nm) the theoretical limit for transverse and vortex domain walls. Magnetic hysteresis loops and first-order reversal curves (FORCs) were measured on several ordered nanowire arrays with different wide-narrow segment lengths ratio and compared with those from homogenous nanowires. The experimental magnetic response evidences a rather complex susceptibility behavior for nanowires with modulated diameter. Micromagnetic simulations on isolated and first-neighbors arrays of nanowires show that the domain wall structure, which depends on the segment diameter, suffers a transformation while crossing the diameter modulation, but without any pinning. The experimental array magnetic behavior can be ascribed to a heterogeneous stray field induced by the diameter modulation, yielding a stronger interaction field at the wide extremity than at the narrow one. The results evidence the possibility to control the domain wall propagation and morphology by modulating the lateral aspect of the magnetic entity

How to Characterize Cylindrical Magnetic Nanowires

Cylindrical magnetic nanowires made through the help of nanoporous alumina templates are being fabricated and characterized since the beginning of 2000. They are still actively investigated nowadays, mainly due to their various promising applications, ranging from high-density magnetic recording to high-frequency devices, passing by sensors, and biomedical applications. They also represent suitable systems in order to study the dimensionality effects on a given material. With time, the development in fabrication techniques allowed to increase the obtained nanowire complexity (controlled crystallinity, modulated composition and/or geometry, range of materials, etc.), while the improvements in nanomanipulation permitted to fabricate system based either on arrays or on single nanowires. On the other side, their increased complexity requires specific physical characterization methods, due to their particular features such as high anisotropy, small magnetic volume, dipolar interaction field between them, and interesting electronic properties. The aim of this chapter was to offer an ample overview of the magnetic, electric, and physical characterization techniques that are suitable for cylindrical magnetic nanowire investigation, of what is the specific care that one needs to take into account and which information will be extracted, with typical and varied examples

Lista de chequeo de las aves de Colombia: Una síntesis del estado del conocimiento desde Hilty & Brown

The taxonomy and knowledge of the distribution of Colombian avifauna has undergone great changes since the publication of “A Guide to the Birds of Colombia” by Hilty & Brown (1986) to the extent that we are unaware of how many and which species inhabit the Colombian territory. Here, we present a checklist of the birds of Colombia updated to August 2017 with a review of 340 references dealing with the distribution of Colombian birds. In sum, we report 1909 species for continental and insular Colombia, 216 of which have been added mainly since 1986. Although there are new data on distribution from 66% of the Colombian avifauna, most publications (87%) and new records (53%) are concentrated to the west of the Eastern cordillera (trans-Andean region). Based on the data we identify those regions of the country with knowledge gaps, which deserve more interest from researchers. Moreover, we encourage the ornithological community to publish their unpublished data and to improve the evidence supporting future new records for the country.La taxonomía y conocimiento de la distribución de la avifauna colombiana ha sufrido grandes cambios desde la publicación de “A Guide to the Birds of Colombia” por Hilty & Brown (1986), a tal punto que hoy no se sabe con precisión cuántas y cuáles especies de aves existen en el territorio colombiano. Presentamos la lista de chequeo de la avifauna de Colombia a agosto de 2017 con base en la revisión de 340 referencias relacionadas con la distribución de la avifauna colombiana. En total, reportamos 1909 especies de aves para el territorio continental e insular del país, de las cuales 216 han sido adicionadas principalmente a partir de 1986. Aunque existe información novedosa sobre distribución para cerca del 66% de la avifauna colombiana, la mayoría de las publicaciones (87%) y registros (53%) se concentran al occidente de la cordillera Oriental (región transandina). Con base en esta información identificamos aquellas áreas del país con vacíos de conocimiento que ameritan mayor interés por parte de los investigadores. Además, estimulamos a la comunidad ornitológica a publicar la información inédita represada, al igual que mejorar la evidencia que soporta los registros novedosos para el país

Magnetic properties of spinel-type oxides NiMn2-xMexO4

New materials, based on the well-known spinel compound NiMn2O4, have been synthesized and characterized from the magnetic point of view. The manganese cation was partially substituted in the general formula NiMn2-xMexO4 , by nonmagnetic and magnetic elements, such as Me = Ga, Zn, Ni and Cr (0 x 1). Prior to the determination of their magnetic properties, the non-substituted spinel NiMn2O4 was carefully characterized and studied as a function of the oxygen stoichiometry, based on the influence of the annealing atmosphere and quenching rate. The ferrimagnetic character was observed in all samples, with a paramagnetic-to-ferromagnetic transition temperature Tc stabilized at 110 K, and well defined long-range antiferromagnetic interactions at lower temperatures, which depend on the applied field and the substitute concentrationAuthors from Chile and O.P. thank projects Fondecyt-Chile 1020066, 7020066 and 1050178. Authors from France and Brazil thank project CAPES/COFECUB 416/03. Authors from France thank Région Bretagne for financial supportPeer reviewe

Configuración de Zentyal para la gestión de los servicios de infraestructura IT

INSTALACIÓN DE ZENTYAL SERVER, TEMÁTICA 1: DHCP SERVER, DNS SERVER Y CONTROLADOR DE DOMINIO, TEMÁTICA 2: PROXY NO TRANSPARENTE , TEMÁTICA 3: CORTAFUEGOS, TEMÁTICA 4: FILE SERVER Y PRINT SERVER, TEMÁTICA 5: VPNEn la etapa final del diplomado de profundización en Linux se tiene como objetivo migrar y ejecutar servicios orientados a la administración y control de una distribución GNU/Linux enfocada en la implementación de servicios de infraestructura IT, proyectados a entornos de trabajos profesionales en niveles de intranet y extranet. Se soluciona gran parte de las problemáticas de migración de los sistemas operativos, servicios y la puesta en marcha de los sistemas de seguridad de la infraestructura de red, utilizando Zentyal Server como plataforma para la administración de la misma. Se explica el procedimiento de la instalación y configuración de Zentyal Server para luego implementar los servicios de gestión de infraestructura IT: DHCP, DNS, Controlador de dominio, Proxy, Corta fuegos, File Server, Print Server y VPN.In the final stage of the in-depth diploma in Linux, the objective is to migrate and execute services oriented to the administration and control of a GNU / Linux distribution focused on the implementation of IT infrastructure services, projected to professional work environments at intranet levels and extranet. A great part of the migration problems of the operating systems, services and the implementation of the security systems of the network infrastructure are solved, using Zentyal Server as a platform for its administration. The Zentyal Server installation and configuration procedure is explained to later implement the IT infrastructure management services: DHCP, DNS, Domain Controller, Proxy, Firewall, File Server, Print Server and VPN

Desafíos en la financiación del sector educativo : diagnóstico y propuestas hacia una reforma del SGP

El presente documento hace parte de las Notas técnicas en educación, a través de las cuales la Secretaría de Educación de Bogotá busca realizar un aporte a las discusiones de coyuntura educativa de la Ciudad y el País