Bibliografía [Cuadernos del Instituto Antonio de Nebrija de estudios sobre la Universidad. 2004, nº 7]

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Efecto de una dieta sin antibióticos, coccidiostatos y aminoácidos sintéticos en pollos sexados Cobb 500

This research was carried out in the experimental area of the Santa Inés Farm belonging to the Faculty of Agricultural Sciences of the Technical University of Machala-Ecuador, with the purpose of evaluating the effect of a diet without antibiotics, coccidiostats and synthetic amino acids, administered to sexed Cobb 500 chickens on the productive parameters: live weight, water and accumulated feed consumption, feed conversion, mortality, ante-mortem weight, carcass weight andcarcass yield percentage. A DCA was used, in which only one factor to manipulate was used, the balance, separating males from females, from a sample of 100 birds, applying one replicate per sex, resulting in 4 experimental units (cages), with 25 sample units (chickens) per replicate, the cages were distributed with a number 1 and 4 (females), 2 and 3 (males), whose data were processed weekly. For the statistical analysis, the Statgraphics Centurión XV.I.® program was used, applying an ANOVA and to establish the differences between means, the Bonferroni multiple comparison procedure was used with a 95.0% confidence level. The results show that the males from the 2nd week onwards present the best weights, as well as the best carcass weight, while in the percentage of carcass yield and drinking water consumption, the females stand out, especially in the last days of the experiment. Showing a marked effect in some variables, when the sexes were subjected to a special diet.La presente investigación se desarrolló en el área experimental de la Granja Santa Inés perteneciente a la Facultad de Ciencias Agropecuarias de la Universidad Técnica de Machala-Ecuador, con la finalidad de evaluar el efecto de una dieta sin antibióticos, coccidiostatos y aminoácidos sintéticos, administrada a pollos Cobb 500 sexados sobre los parámetros productivos: Peso vivo, consumo de agua y alimento acumulado, conversión alimenticia, mortalidad, peso ante mortem, peso de la canal y porcentaje de rendimiento de la canal. Se empleó un DCA, en el cual se utilizó un único factor a manipular, el balanceado, separando los machos de las hembras, de una muestra de 100 aves, aplicando una réplica por sexo, dando como resultado 4 unidades experimentales (jaulas), con 25 unidades muestrales (pollos) por replica, las jaulas fueron distribuidas con un número 1 y 4 (hembras), 2 y 3 (machos),  cuyos datos se procesaron semanalmente. Para el análisis estadístico, se empleó el programa Statgraphics Centurión XV.I.®, aplicando un ANOVA y para establecer las diferencias entre las medias se usó el procedimiento de comparación múltiple de Bonferroni con un nivel del 95,0% de confianza. Los resultados muestran que los machos a partir de la 2da semana presentan los mejores pesos, así como el mejor peso de la canal, mientras que en el porcentaje de rendimiento de la canal y consumo de agua de bebida destacan las hembras sobre todo en los  últimos días del experimento. Demostrando un efecto marcado en algunas variables, al someter a los sexos a una dieta especial

Helios modulates the maturation of a CA1 neuronal subpopulation required for spatial memory formation

Currently, molecular, electrophysiological and structural studies delineate several neural subtypes in the hippocampus. However, the precise developmental mechanisms that lead to this diversity are still unknown. Here we show that alterations in a concrete hippocampal neuronal subpopulation during development specifically affect hippocampal-dependent spatial memory. We observed that the genetic deletion of the transcription factor Helios in mice, which is specifically expressed in developing hippocampal calbindin-positive CA1 pyramidal neurons (CB-CA1-PNs), induces adult alterations affecting spatial memory. In the same mice, CA3-CA1 synaptic plasticity and spine density and morphology in adult CB-CA1-PNs were severely compromised. RNAseq experiments in developing hippocampus identified an aberrant increase on the Visinin-like protein 1 (VSNL1) expression in the hippocampi devoid of Helios. This aberrant increase on VSNL1 levels was localized in the CB-CA1-PNs. Normalization of VSNL1 levels in CB-CA1-PNs devoid of Helios rescued their spine loss in vitro. Our study identifies a novel and specific developmental molecular pathway involved in the maturation and function of a CA1 pyramidal neuronal subtype

Citizen culture for solid waste management through research as a pedagogical strategy

A nivel mundial, en América latina y el Caribe, la cultura ciudadana para el manejo de residuos sólidos es una debilidad a nivel poblacional y cultural que termina contaminando el medio. El estudio tuvo como propósito fomentar la cultura ciudadana para el manejo de residuos sólidos mediante la investigación como estrategia pedagógica. La metodología se orientó bajo el enfoque cualitativo, utilizando el tipo de investigación acción, desde un diseño descriptivo, exploratorio. Para la recolección de datos se utilizaron técnicas como; observación participante y diario de campo. La población estuvo conformada por sesenta (60) estudiantes de la IED Tercera Mixta del municipio de Fundación Magdalena. Dando como resultado el diseño de actividades pedagógicas para identificar las concepciones y hábitos de los estudiantes con respecto al manejo de los residuos sólidos generados en la institución propiciando conductas pro ambientales como reciclaje, reutilización y reducción de residuos sólidos generados en la institución y sus alrededores.At the global level, in Latin America and the Caribbean, the citizen culture for solid waste management is a weakness at the population and cultural level that ends up contaminating the environment. The purpose of the study was to promote citizen culture for solid waste management through research as a pedagogical strategy. The methodology was oriented under the qualitative approach, using the type of action research, from a descriptive, exploratory design. For the collection of data, techniques such as; participant observation and field diary. The population was conformed by sixty (60) students of the Third Mixed IED of the municipality of Magdalena Foundation. Resulting in the design of pedagogical activities to identify the conceptions and habits of students regarding the management of solid waste generated in the institution, promoting pro environmental behaviors such as recycling, reuse and reduction of solid waste generated in the institution and its surroundings

Experiencias en el aula: tercer encuentro de prácticas pedagógicas innovadoras.

Experiencias de profesores en su quehacer en los distintos ambientes de aprendizaje presenciales y a distancia.Para el Centro de Excelencia Docente aeiou constituye un honor presentar la publicación del Tercer Encuentro de Prácticas Pedagógicas Innovadoras en el que se destacan cuarenta trabajos de profesores de UNIMINUTO provenientes de diferentes sedes. Con este encuentro son ya tres que bajo la dirección de aeiou los profesores han compartido su quehacer en los distintos ambientes de aprendizaje presenciales y a distancia. Cada año el Centro de Excelencia Docente invita a los profesores a participar en este evento, para el 2108 además de la inscripción voluntaria por parte de cada profesor, se invitó al estudiantado a que postularan a sus profesores que consideraban eran innovadores y creativos en el cumplimiento de su función docente y se obtuvo una respuesta importante por parte de los estudiantes, que para algunos profesores resultó sorpresiva porque quizás no habían considerado que el trabajo que hacían en su ambiente de aprendizaje era diferente, fuera de lo común. Luego de una evaluación de jurados nacionales e internacionales de las prácticas presentadas y de la realización del evento, que tuvo como novedad hacerlo de forma simultánea en cuatro sedes donde UNIMINUTO tiene presencia: Buga, Ibagué, Pereira y Bogotá, se comparte la presente publicación para tener como referencia y evidencia el trabajo que los profesores hacen a diario

Sin / Sense

Sexto desafío por la erradicación de la violencia contra las mujeres del Institut Universitari d’Estudis Feministes i de Gènere «Purificación Escribano» de la Universitat Jaume

Investigación y jóvenes investigadores: La excelencia en la precariedad

El presente texto contiene una revisión del actual estado material de los jóvenes investigadores, centrándose en la figura del doctorando, pero recogiendo también aquellas figuras no estabilizadas que, a pesar de alejarse del grupo de jóvenes, por circunstancias profesionales se encuentran en contextos materiales próximos. En ciertos sectores de la juventud investigadora, estas condiciones pueden derivar en una pérdida de confianza en las expectativas de futuro y tener consecuencias negativas de carácter anímico, emocional y mental. En los casos más extremos se produce, de hecho, el abandono de la carrera investigadora. Recogiendo el espíritu de una publicación previa en 1994 en la Revista Española de Física, “Algunas consideraciones sobre la situación de los investigadores jóvenes”, se actualiza el contexto social en el que se realiza la labor científico-técnica en España, repasando el rol de los factores tanto internos como externo

Operando exploration of tribochemical decomposition of FeS2 thin films and mineral iron pyrite

Tribochemical decomposition of thin-film synthetic iron disulfide and mineral iron pyrite was studied using a combination of operando mass-spectrometry coupled to ultrahigh vacuum tribochemical cell and these gas expansion system. The composition and kinetics of gas emission were analyzed using an original methodology. It was found that carbon-containing gases were dominating. The sulfur-containing gases comprised H2S, COS and CS2. The latter two were unexpected. The emission of the gases was traced back to solid-state chemical reactions kinetically controlled by the precursor concentrations and driven through non-thermal mechanisms, which we tentatively assigned to formation of sulfur radicals.This work was supported by the Ministry of Science, Innovation and University of Spain (grants PID2019- 111063RB-I00, PID2020-112770RB-C22, PID2020-117573GB-I00, RTI2018-099794-B-I00, and TED2021-129950B-I00). We acknowledge the service from the MiNa Laboratory at IMN and funding from Madrid Community (project S2018/NMT-4291 TEC2SPACE), Ministry of Science, Innovation and Universities of Spain (project CSIC13-4E-1794), and EU (FEDER, FSE) The authors acknowledge the support from The Centre for Micro Analysis of Materials (CMAM)—Universidad Autónoma de Madrid, for the beam time proposal (Analysis of surface elemental transformations induced by mechanochemical reactions with metal sulfides) with code STD-022/23, and its technical staff for their contribution to the operation of the accelerator.Peer reviewe

Dataset of Operando Exploration of Tribochemical Decomposition in Synthetic FeS2 thin film and Mineral Iron Pyrite

FeS2 thin films were obtained by sulfuration of Fe coatings, which were deposited by thermal evaporation of iron powder (Goodfellow, 99.99%) on soda lime glass substrates under high vacuum. The initial thickness of the Fe coatings was 300±20 nm as measured using quartz crystal microbalance. The Fe coating was transferred into a glass ampoule, which contained a small amount of sulfur powder (Merck, 99.99%) placed at one end. The ampoule was evacuated down to 10-5 mbar and sealed. Then, sulfur was sublimated by heating to 300ºC for 20 h, while sulfur vapour at a pressure of about 0.065 bar reacted with the Fe film. After sulfuration, the coatings were kept in the same sealed ampoules at room temperature until they were characterized. Natural pyrite was used to contrast the results obtained for artificial FeS2 thin film. A sheet of iron pyrite was cut from a native crystal proceeding from Peru mines and polished. X-ray diffraction analysis showed a typical cubic crystal structure of the mineral sample. The iron coatings' crystal structure was analyzed both before and after sulfuration using grazing-angle X-ray diffraction (XRD). This was accomplished by employing Cu Kα radiation and maintaining a fixed incidence angle of 1.7°. To determine the mean crystallite size, the Scherrer formalism was applied to the main diffraction band (200). Film thickness measurements were conducted at the film edge utilizing a stylus profilometer, achieving an accuracy of 10 nm. The mechanical properties of the FeS2 coatings were investigated through nanoindentation (G200, KLA Corp.), utilizing a Berkovich diamond tip in dynamic contact mode. The maximum indentation depth was 100 nm constrained to remain below 10% of the total coating thickness. The loading cycle was carried out at a constant indentation strain rate of 0.1 s-1 and a small oscillating force was superimposed to this loading ramp (75 Hz of frequency, amplitude of 2 nm). Continuous measurement of the contact stiffness was achieved on the basis of the phase lag between the sinusoidal force and the penetration produced. X-ray Photoemission Spectrometry (XPS) was used to obtain information on chemical state of various elements under ultra-high vacuum (UHV) with a pressure below 10-8 Pa. Mg Kα radiation with an energy of 1253.6 eV was employed. To eliminate any airborne adsorbed contaminants from the sample surface, ensuring a pristine surface for subsequent XPS analysis, the samples underwent Ar+ ion sputtering with an energy of 1 keV and an incident angle of 60° with respect to the sample normal. The sputtering depth was around 1.3 Å. It should be noted that Ar+ ions for sputtering can potentially alter the chemical oxidation state of Fe and/or S and/or change the surface composition due to preferential sputtering. No additional treatment was performed. High-resolution XPS analysis of Fe 2p, S 2p, O 1s, and C 1s was conducted through the fitting process employing the minimum possible number of components compatible with the expected chemistry. For instance, both the Fe 2p3/2 and Fe 2 p1/2 spin-orbit peaks were fitted to ensure the coherence of the procedure, while assuming a Shirley background. For the sake of simplicity, only the Fe 2p3/2 bands are discussed here. The S 2p peak was fitted employing a S 2p3/2 S 2p1/2 doublet, considering the theoretical spin-orbit coupling ratio of 1:2. A fixed separation of 1.2 eV between the S 2p3/2 and S 2p1/2 was maintained based on literature for data processing.Electron Stimulated Desorption (ESD) coupled with mass spectrometry was used to examine the chemical composition of the adsorbed layers and the surface chemical groups. The sample was bombarded with electrons using an electron gun positioned at a 60° angle to the surface normal. Unless otherwise mentioned, the electron energy used was 600 eV. The ions, which were generated on the surface due to electron bombardment, released from the sample and were detected using a quadrupole mass spectrometer, situated in front of the sample. More details about the setup and process of the ESD experimental system can be found elsewhere. Thermal Gravimetric analysis of thin films was used to analyse the gases emitted during progressive heating under both Ar and dry air flows using a mass spectrometer. The rate of linear heating was set at 5, 10, and 20 °C/min. The emitted gases were analysed in the range of 1-90 a.m.u. The Rutherford Backscattering Spectrometry (RBS) and Elastic Recoil Detection Analysis (ERDA) techniques, available at the Centre of Microanalysis of Materials of Autonomous University of Madrid, were employed to determine the elemental composition of the sample surfaces. Its 5MV linear tandem accelerator facility provides the ion beams to carry out the characterization with these techniques. In this study, a collimated He+ beam with energies of 3.035 or 4.260 MeV extracted from the accelerator was used, while choice of these energies’ values justified under resonant conditions for oxygen and carbon respectively. For RBS analysis, the backscattered ions were detected at an angle of 170° with respect to the direction of the incident ion beam. In the case of ERDA, the ions were directed to the surface at an incident angle of 75° with respect to the surface normal. Recoiled particles were collected at 30°. To filter out heavier ions, a 19 µm thick mylar film was placed in front of the detector to obtain the hydrogen depth profile. The total ion dose in each measurement was set to 15 µC with a particle flux of 5.5x1012 cm-2 s-1 and a probe size of 1.5x1.5 mm2. The spectra were taken with the samples at random orientations. For energy-to-depth conversion, common SRIM (Stopping and Range of Ions in Matter) energy loss data were used, along with reference samples of MgH2 Er-doped TiO2 coatings. The RBS-ERDA spectra were fitted using SIMNRA simulation software. The gases emitted during mechanical activation of the materials were analysed using an original UHV experimental system equipped with a quadrupole mass spectrometer (Hiden HALO), a reciprocating motion UHV-grade friction cell, and a dynamic gas expansion system. Such a configuration allows accurate quantification of minute emission rates down to 1 pmol s-1. The samples were rubbed under UHV using alumina spheres, 3 mm in diameter. The rubbing conditions, unless otherwise stated, were as follows: the normal load of 0.44 N, the frequency of reciprocating motion of 1 s-1, and the mean rubbing velocity of 0.18 m s-1. The experimental system is schematically shown in Figure 1 and described in detail elsewhere. Before the tests, the alumina spheres were thoroughly degreased consecutively in acetone and isopropanol ultrasonic baths. After drying, they were submerged in a hot Piranha solution to remove carbon and metal residues, rinsed with ultrapure water, and dried in an N2 stream. The differential mass spectra (DMS) were derived by subtracting the mean steady background mass spectra from the mean mass spectra recorded during the application of the mechanical stimulus. Only statistically significant changes (α=0.05) in DMS were analysed among the channels within the 1 – 100 a.m.u. range. To ensure comparability, the mass spectra were normalized by dividing by the total ion current in each spectrum. The tentative identification of ion species was based on reference cracking patterns from the NIST Webbook (NIST Webbook). The gas composition was determined through a backward stepwise regression method, in which we utilized reference mass spectra of various potential gas precursors. These spectra were fitted in various combinations to the experimental DMS with the aim of identifying the combination that included the fewest precursors and achieved a high R2adj value. Behavioural analysis (BA) was employed to develop better understanding of the mechanisms of underlying tribochemical processes. BA allows to explore the short- and long-term trends of highly dynamic emission time series, to establish the degree of correlation between the mass spectrometer signals, and to trace them back to the possible emission sources in the mechanically affected bulk material and/or on the mechanically affected surfaces. Chemical changes in the Mechanically Affected Zones (MAZ) were studied using vibrational spectroscopy (Raman and FTIR). All the results were benchmarked against the spectra obtained from neighbouring pristine surfaces. Raman spectra were measured using a 532 nm laser in air. Infrared micro-reflectance spectra were obtained using a micro-FTIR spectrometer.Datasets of mass-spectrometry signals were obtained in the experiments with non-thermal tribochemical decomposition of synthetic thin-film iron sulphide and mineral iron pyrite. Tribochemical reactions were studied on a micrometre scale using localized rubbing under ultrahigh vacuum. Mechanically Stimulated Gas Emission Mass-Spectrometry (MSGE-MS) including the Dynamic gas expansion method was used to determine the kinetic parameters of gas emission and the composition of the emitted gases. The study was complemented by structural, morphological, tribological, mechanical and surface analyses. It was found that carbon-containing gases were dominating. The sulfur-containing gases comprised H2S, COS and CS2. The latter two were unexpected. The emission of these gases was traced back to solid-state chemical reactions kinetically controlled by the precursor concentrations and driven through non-thermal mechanisms, which we tentatively assigned to formation of sulfur radicals.This study was co-funded by Spanish Ministry for Science and Innovation (grants PID2019-111063RB-I00, PID2020-112770RB-C22, PID2020-117573GB-I00, RTI2018-099794-B-I00, and TED2021-129950B-I00) and funding from Madrid Community (project S2018/NMT-4291 TEC2SPACE), Ministry of Science and Innovation of Spain (project CSIC13-4E-1794) and EU (FEDER, FSE).1. Dataset of mass-spectrometry time series of mechanically stimulated gas emission from sodium alanate (NaAlH4) pellets under vacuum.-- 2. Dataset of Thermal Programmed Desorption – Mass-Spectrometry (TPD-MS) analysis of sodium alanate.-- 3. Dataset of X-ray diffraction of sodium alanate.-- 4. Dataset of micro-FTIR spectra of pristine and mechanically activated surfaces of pellets of sodium alanate.-- 5. Dataset of Raman spectra measured on the surfaces of pellets of sodium alanate.N