One pot solvothermal synthesis of organic acid coated magnetic iron oxide nanoparticles

Indexación: ScieloABSTRACT In this work we present the synthesis and characterization of iron oxide nanoparticles (IONPs), which were structurally and magnetically characterized. The use of iron salts and an organic acid (l-serine or ascorbic acid) as precursors under solvothermal conditions yielded these coated IONPs. The powder X-ray diffraction pattern of FeO-1 and FeO-2 is consistent with hematite (α-Fe2O3) and hematite-maghemite ((α-Fe2O3/γ-Fe2O3) respectively. The TEM analysis permits to estimate an average size of 10 nm for the FeO-1 sample. The magnetic characterization of the samples through the M(H) plots showed a very low coercivity value for both samples, being 53 Oe for FeO-1 and 10 Oe for FeO-2, indicating the very weak ferromagnetic character of the synthesized iron oxide species. Even though both organic acids under solvothermal conditions permit to obtain coated IONPs in one pot reaction, l-serine produces a more narrow-size distribution

A quarterly fiscal database for the euro area based on intra-annual fiscal information

The analysis of the macroeconomic impact of fiscal policies in the euro area has been traditionally limited by the absence of quarterly fiscal data. To overcome this problem, we provide two new databases in this paper. Firstly, we construct a quarterly database of euro area fiscal variables for the period 1980-2008 for a quite disaggregated set of fiscal variablessecondly, we present a real-time fiscal database for a subset of fiscal variables, composed of bi-annual vintages of data for the euro area period (2000-2009). All models are multivariate, state-space mixed-frequencies models estimated with available national accounts fiscal data (mostly annual) and, more importantly, monthly and quarterly information taken from the cash accounts of the governments. We provide not seasonallyand seasonally-adjusted data. Focusing solely on intra-annual fiscal information for interpolation purposes allows us to capture genuine intra-annual "fiscal" dynamics in the data. Thus, we provide fiscal data that avoid some problems likely to appear in studies using fiscal time series interpolated on the basis of general macroeconomic indicators, namely the well-known decoupling of tax collection from the evolution of standard macroeconomic tax bases (revenue windfalls/shortfalls)

Which Innovative Solutions of Non-Technological and Technological Nature are Needed to Improve Tourism Services? A Case of Tungurahua Province in Ecuador

The present empirical study aims to provide a new conceptual framework for the regional tourism industry of the Province of Tungurahua-Ecuador that emerged from a combined application of stakeholder engagement and research-practice approaches. These preliminary outcomes from in-depth focus group assessments and surveys applied to tourism experts, industry practitioners, government\u27s representatives, and tourists revealed that a synergic/collaborative work across tourism stakeholders have the potentials to create innovative touristic products and services, thus solving progressively the existing issues observed in the regional tourism, travel and hospitality sectors. Resulting tailor-made tourism products, mainly based on advanced technology, may represent the first steps of improvements to be taken into consideration prior to evolving to the development and implementation of smart cities and smart tourism concepts in this region where tourism activities are one of the most important revenue for the national and regional tourism industry

Variability of nitrogen mineralization from organic matter in agricultural soils in the north of Colombia

Variation of Nitrogen mineralization (Nm) and its relationship to physicochemical factors in soils of an irrigation district in the North of Colombia was evaluated. Physicochemical parameters were measured in topsoil (0–30 cm) samples taken from 22 points in agricultural lands (10 in the dry season, 12 in the wet season). Nm was estimated from organic matter (OM) content. Soil parameters in the study area are suitable for crop development, although they present variations between the dry and wet season, where the soil pH varies of slightly acidic to neutral and the OM content decreases. Additionally, in the dry season there was a positive correlation with pH, OM and C/N ratio and, during wet season between OM, sand, clay and bulk density. In both seasons, a negative correlation between silt and Nm was common. Environmental and soil conditions in the study area are favourable for Nm because during the dry season the accumulation of OM is favoured. Understanding how physicochemical factors influence Nm is essential for agricultural activities and the development of sustainable ecosystem services

Impacto del nivel de cumplimiento del perfil de competencias en el clima laboral en una empresa pública del sector eléctrico del Ecuador

El objetivo de la presente investigación es conocer mediante un estudio empírico si el nivel de cumplimiento del perfil de competencias incide en el nivel de clima laboral de una organización. El nivel de cumplimiento del perfil de competencias abarca el análisis del cumplimiento del perfil duro (formación, capacitación y experiencia), del nivel de desempeño en las actividades esenciales del cargo y la identificación del grado de desarrollo de las competencias requeridas para el perfil de cada cargo. Para alcanzar el objetivo propuesto se consideró una muestra de 4100 personas distribuidas en nueve (9) provincias del Ecuador. El análisis permitió validar adicionalmente la calidad del instrumento de medición del clima laboral. Se cuenta con una herramienta de medición del clima laboral validada. La herramienta del clima laboral generada durante la investigación cuenta con criterios psicométricos que garantizan su confiabilidad y validez. Dentro de los principales hallazgos se encontró que en la versión final generada como producto de esta investigación se cuenta con un instrumento que: (a) Demuestra consistencia interna de los diferentes ítems de cada escala, (b) Contiene ítems que correlacionan con el factor que le corresponde y no en otros, y, (c) Garantiza que cada factor individual aporta al factor general del instrumento de clima laboral. Sobre el propósito de la investigación se ha llegado a concluir que el nivel de cumplimiento del perfil de competencias no tendría una influencia directa en el nivel de clima laboral. Esto puede deberse a que la evaluación considero solo el concepto de "rendimiento en la tarea" y no el de "rendimiento en el contexto". Si se logra determinar dentro del análisis estadístico que el nivel de desarrollo de las competencias tendría una influencia sobre el nivel de eficacia en las actividades esenciales o rendimiento en la tarea. Esta correlación es mayor que el nivel de cumplimiento del perfil duro

Catena-(bis((1,10-Phenanthroline-N,N')-copper(II)) hydroxy-bis( phosphato)-tris(dioxo-vanadium(v))): a polymorphic phase driven by disorder.

International audienceIn the present paper a copper(II) phosphovanadate is presented and formulated as [Cu6(phen)6(VVO2)6(PO4)6(VVO2HO)3] (1a). This compound was obtained by hydrothermal synthesis and crystallizes in the triclinic group P-1, with a = 10.6290(5), b = 17.4275(8), c = 23.6151(11) Å; α = 92.888(4)°, β = 98.910(4)° and γ = 91.995(4)°. The leitmotif in (1a) is almost identical to some previously reported ones, viz. [Cu(phen)(VVO2)(PO4)]2[VVO2(OH)] (2); [Cu(phen)(VVO2)(PO4)]2[VIVO2(H2O)] (3) except for the fact that the small cells found in (2)-(3) are tripled in (1a). The reasons driving to these differences are subtle, and reside in the way in which the disorder in some vanadate groups takes place, viz., completely at random in (2)-(3) thus leading to a small "average" cell, while keeping some systematics in (1a) thus needing for a larger motif to take account of its repetition scheme in the crystal. The magnetic unit in the structure of (1a) is defined by a dinuclear system of CuII bonded by a μ2,η1-PO4 bridge. A fit of the corresponding magnetic data of (1a) was done, using the van Vleck equation for two S = ½ centres View the MathML source. The parameters obtained by the fit of the experimental data were g = 2.1 and J = −3.5 cm−1

Gestión y comunicación del patrimonio:: Estrategias para un turismo sostenible en el Centro Histórico de Pasa. Ecuador

The importance of the Historic Centers was analyzed as evidence of the evolution of the nation, of the transitions of historical periods and the lifestyle of its inhabitants, as well as tourist potential, which would bring economic reactivation and relevance to Pasa, the locality where the development of this research takes place. From an informal qualitative approach, talks, focus groups and field studies were carried out to collect the necessary information and truthfully diagnose the current situation of Pasa in terms of tourism management in its Historic Center. To conclude, a series of strategies capable of contributing favorably to the positioning of Pasa as a tourist product open to Ecuador and the world are proposed.Se analizó la importancia de los Centros Históricos como evidencia de la evolución de la nación, de las transiciones de períodos históricos y el estilo de vida de sus habitantes, además, como potencial turístico, que traería reactivación económica y relevancia a Pasa, localidad donde toma lugar el desarrollo de esta investigación. Desde un enfoque cualitativo, se llevaron a cabo charlas, grupos focales y estudios de campo para recabar la información necesaria y diagnosticar verazmente la situación actual de Pasa en cuanto a la gestión del turismo en su Centro Histórico. Para concluir se plantean una serie de estrategias capaces de contribuir favorablemente al posicionamiento de Pasa como un producto turístico abierto a Ecuador y al mundo

New highly charged iron(III) metal-organic cube stabilized by a bulky amine.

In this work, we report a new octanuclear cluster based on FeIII and the ligand 1H-imidazole-4,5-dicarboxylic acid, [Et3NH]12[Fe8(IDC)12]·10DMF·13H2O (1), with a metal core containing eight FeIII connected by only one type of organic ligand. A peak at 573 m/z in the mass spectra of the compound suggests the adduct species {[Fe8(IDC)12]+8H}4-. By X-ray photoelectron spectroscopy, the oxidation state of the iron cation was confirmed to be 3+, also identifying the presence of a quaternary nitrogen species, which act as a countercation of the anionic metal core [Fe8(IDC)12]12-. Mössbauer spectra recorded at different temperatures show an isomer shift and quadrupole splitting parameters that confirm the existence of only FeIII-HS in the structure of 1. X-ray analysis reveals that compound 1 crystallizes in the orthorhombic system space group Ibam, confirming a molecular cluster structure with an almost regular cube as geometry, with the FeIII atoms located at the corners of the cube and connected by μ-1κ2 N,O:2κ2 N',O‴-IDC3- bridges. Additionally, the magnetic measurements reveal a weak antiferromagnetic coupling in the Fe8 III coordination cluster (J = -3.8 cm-1). To the best of our knowledge, 1 is the first member of the family of cubes assembled with 1H-imidazole-4,5-dicarboxylic acid and FeIII cation, exhibiting high pH stability over a broad pH range, making it an ideal candidate for the design of supramolecular structures and metal-organic frameworks

Different resource allocation strategies result from selection for litter size at weaning in rabbit does

This study examined the effect of long-term selection of a maternal rabbit line, solely for a reproductive criterion, on the ability of female rabbits to deal with constrained environmental conditions. Female rabbits from generations 16 and 36 (n = 72 and 79, respectively) of a line founded and selected to increase litter size at weaning were compared simultaneously. Female rabbits were subjected to normal (NC), nutritional (NF) or heat (HC) challenging conditions from 1st to 3rd parturition. Animals in NC and NF were housed at normal room temperatures (18°C to 25°C) and respectively fed with control (11.6 MJ digestible energy (DE)/kg dry matter (DM), 126 g digestible protein (DP)/kg DM, and 168 g of ADF/kg DM) or low-energy fibrous diets (9.1 MJ DE/kg DM, 104 g DP/kg DM and 266 g ADF/kg DM), whereas those housed in HC were subjected to high room temperatures (25°C to 35°C) and the control diet. The litter size was lower for female rabbits housed in both NF and HC environments, but the extent and timing where this reduction took place differed between generations. In challenging conditions (NF and HC), the average reduction in the reproductive performance of female rabbits from generation 16, compared with NC, was &#8722;2.26 (P<0.05) and &#8722;0.51 kits born alive at 2nd and 3rd parturition, respectively. However, under these challenging conditions, the reproductive performance of female rabbits from generation 36 was less affected at 2nd parturition (&#8722;1.25 kits born alive), but showed a greater reduction at the 3rd parturition (&#8722;3.53 kits born alive; P<0.05) compared with NC. The results also showed differences between generations in digestible energy intake, milk yield and accretion, and use of body reserves throughout lactation in NC, HC and NF, which together indicate that there were different resource allocation strategies in the animals from the different generations. Selection to increase litter size at weaning led to increased reproductive robustness at the onset of an environmental constraint, but failure to sustain the reproductive liability when the challenge was maintained in the long term. This response could be directly related to the shortterm environmental fluctuations (less severe) that frequently occur in the environment where this line has been selected.The authors thank Professor Enrique Blas Ferrer for his valuable comments on the initial version of this document, Juan Carlos Moreno for his help in conducting the trial at the experimental farm, and the Ministry of Economy and Competitiveness (Project: AGL2011-30170-C02-01) for economic support.Savietto, D.; Cervera Fras, MC.; Ródenas Martínez, L.; Martínez Paredes, EM.; Baselga Izquierdo, M.; García Diego, FJ.; Larsen, T.... (2014). Different resource allocation strategies result from selection for litter size at weaning in rabbit does. Animal. 8(4):618-628. https://doi.org/10.1017/S1751731113002437S61862884García-Diego, F.-J., Pascual, J. J., & Marco, F. (2011). Technical Note: Design of a large variable temperature chamber for heat stress studies in rabbits. World Rabbit Science, 19(4). doi:10.4995/wrs.2011.938Ragab, M., & Baselga, M. (2011). A comparison of reproductive traits of four maternal lines of rabbits selected for litter size at weaning and founded on different criteria. Livestock Science, 136(2-3), 201-206. doi:10.1016/j.livsci.2010.09.009Friggens, N. C. (2003). Body lipid reserves and the reproductive cycle: towards a better understanding. Livestock Production Science, 83(2-3), 219-236. doi:10.1016/s0301-6226(03)00111-8Littell, R. C., Henry, P. R., & Ammerman, C. B. (1998). Statistical analysis of repeated measures data using SAS procedures. Journal of Animal Science, 76(4), 1216. doi:10.2527/1998.7641216xEstany, J., Baselga, M., Blasco, A., & Camacho, J. (1989). Mixed model methodology for the estimation of genetic response to selection in litter size of rabbits. Livestock Production Science, 21(1), 67-75. doi:10.1016/0301-6226(89)90021-3Fernández-Carmona, J., Alqedra, I., Cervera, C., Moya, J., & Pascual, J. J. (2003). Effect of lucerne-based diets on performance of reproductive rabbit does at two temperatures. Animal Science, 76(2), 283-295. doi:10.1017/s1357729800053534Fernández-Carmona, J., Cervera, C., Sabater, C., & Blas, E. (1995). Effect of diet composition on the production of rabbit breeding does housed in a traditional building and at 30°C. Animal Feed Science and Technology, 52(3-4), 289-297. doi:10.1016/0377-8401(94)00715-lHarano, Y., Ohtsuki, M., Ida, M., Kojima, H., Harada, M., Okanishi, T., … Shigeta, Y. (1985). Direct automated assay method for serum or urine levels of ketone bodies. Clinica Chimica Acta, 151(2), 177-183. doi:10.1016/0009-8981(85)90321-3Dauncey, M. J. (1990). Thyroid hormones and thermogenesis. Proceedings of the Nutrition Society, 49(2), 203-215. doi:10.1079/pns19900024Savietto, D., Blas, E., Cervera, C., Baselga, M., Friggens, N. C., Larsen, T., & Pascual, J. J. (2012). Digestive efficiency in rabbit does according to environment and genetic type. World Rabbit Science, 20(3). doi:10.4995/wrs.2012.1152Falconer, D. S. (1990). Selection in different environments: effects on environmental sensitivity (reaction norm) and on mean performance. Genetical Research, 56(1), 57-70. doi:10.1017/s0016672300028883Vicente, J., & García-Ximénez, F. (1993). Effects of strain and embryo transfer model (embryos from one versus two donor does/recipient) on results of cryopreservation in rabbit. Reproduction Nutrition Development, 33(1), 5-13. doi:10.1051/rnd:19930101Quiniou, N., Renaudeau, D., Dubois, S., & Noblet, J. (2000). Influence of high ambient temperatures on food intake and feeding behaviour of multiparous lactating sows. Animal Science, 70(3), 471-479. doi:10.1017/s1357729800051821Theilgaard, P., Sánchez, J. P., Pascual, J. J., Friggens, N. C., & Baselga, M. (2006). Effect of body fatness and selection for prolificacy on survival of rabbit does assessed using a cryopreserved control population. Livestock Science, 103(1-2), 65-73. doi:10.1016/j.livsci.2006.01.007Brecchia, G., Bonanno, A., Galeati, G., Federici, C., Maranesi, M., Gobbetti, A., … Boiti, C. (2006). Hormonal and metabolic adaptation to fasting: Effects on the hypothalamic–pituitary–ovarian axis and reproductive performance of rabbit does. Domestic Animal Endocrinology, 31(2), 105-122. doi:10.1016/j.domaniend.2005.09.006Piles, M., Garreau, H., Rafel, O., Larzul, C., Ramon, J., & Ducrocq, V. (2006). Survival analysis in two lines of rabbits selected for reproductive traits1. Journal of Animal Science, 84(7), 1658-1665. doi:10.2527/jas.2005-678Sanchez, J. P., Baselga, M., & Ducrocq, V. (2006). Genetic and environmental correlations between longevity and litter size in rabbits. Journal of Animal Breeding and Genetics, 123(3), 180-185. doi:10.1111/j.1439-0388.2006.00590.xQuevedo, F., Cervera, C., Blas, E., Baselga, M., & Pascual, J. J. (2006). Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 2. Lactation and growing period. Animal Science, 82(5), 751-762. doi:10.1079/asc200688Vicente, J. S., & García-Ximénez, F. (1996). Direct transfer of vitrified rabbit embryos. Theriogenology, 45(4), 811-815. doi:10.1016/0093-691x(96)00010-6Coureaud, G., Fortun-Lamothe, L., Langlois, D., & Schaal, B. (2007). The reactivity of neonatal rabbits to the mammary pheromone as a probe for viability. animal, 1(7), 1026-1032. doi:10.1017/s1751731107000389Rommers, J. M., Boiti, C., Brecchia, G., Meijerhof, R., Noordhuizen, J. P. T. M., Decuypere, E., & Kemp, B. (2004). Metabolic adaptation and hormonal regulation in young rabbit does during long-term caloric restriction and subsequent compensatory growth. Animal Science, 79(2), 255-264. doi:10.1017/s1357729800090111Piles, M., García, M. L., Rafel, O., Ramon, J., & Baselga, M. (2006). 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2-(2-Pyridylamino)pyridinium tetra­chlorido­zincate(II)

The structure of the title compound, (C10H10N3)2[ZnCl4], is composed of C10H9N3H+ (DPAH+) cations and [ZnCl4]2− anions. The two pyridyl rings of DPAH+ are approximately coplanar, with a dihedral angle of 7.2 (2)° between their corresponding least-squares planes. The proton is disordered in a one-to-one ratio over the two chemically equivalent pyridyl N atoms. An intra­molecular hydrogen bond is formed between the pyridinium H atom and the pyridyl N atom of the other pyridyl ring. The Zn atom lies on a twofold rotation axis. There are also some weak N—H⋯Cl hydrogen bonds. These inter­actions lead to the formation of an alternating zigzag chain in the solid state. The results clearly show that reducing agents normally used in hydro­thermal syntheses, such as metallic zinc employed here, are also active in terms of coordination chemistry