1,481 research outputs found
Visualization of Skewed Data: A Tool in R
In this work we present a visualization tool specifically tailored to deal
with skewed data. The technique is based upon the use of two types of notched
boxplots (the usual one, and one which is tuned for the skewness of the data),
the violin plot, the histogram and a nonparametric estimate of the density. The
data is assumed to lie on the same line, so the plots are compatible. We show
that a good deal of information can be extracted from the inspection of this
tool; in particular, we apply the technique to analyze data from synthetic
aperture radar images. We provide the implementation in R.Comment: Submitted to the Revista Colombiana de Estad\'istic
Radial velocities and metallicities from infrared Ca II triplet spectroscopy of open clusters II. Berkeley 23, King 1, NGC 559, NGC 6603 and NGC 7245
Context: Open clusters are key to studying the formation and evolution of the
Galactic disc. However, there is a deficiency of radial velocity and chemical
abundance determinations for open clusters in the literature. Aims: We intend
to increase the number of determinations of radial velocities and metallicities
from spectroscopy for open clusters. Methods: We acquired medium-resolution
spectra (R~8000) in the infrared region Ca II triplet lines (~8500 AA) for
several stars in five open clusters with the long-slit IDS spectrograph on the
2.5~m Isaac Newton Telescope (Roque de los Muchachos Observatory, Spain).
Radial velocities were obtained by cross-correlation fitting techniques. The
relationships available in the literature between the strength of infrared Ca
II lines and metallicity were also used to derive the metallicity for each
cluster. Results: We obtain = 48.6+/-3.4, -58.4+/-6.8, 26.0+/-4.3 and
-65.3+/-3.2 km s-1 for Berkeley 23, NGC 559, NGC 6603 and NGC 7245,
respectively. We found [Fe/H] =-0.25+/-0.14 and -0.15+/-0.18 for NGC 559 and
NGC 7245, respectively. Berkeley 23 has a low metallicity, [Fe/H]
=-0.42+/-0.13, similar to other open clusters in the outskirts of the Galactic
disc. In contrast, we derived a high metallicity ([Fe/H] =+0.43+/-0.15) for NGC
6603, which places this system among the most metal rich known open clusters.
To our knowledge, this is the first determination of radial velocities and
metallicities from spectroscopy for these clusters, except NGC 6603, for which
radial velocities had been previously determined. We have also analysed ten
stars in the line of sight to King 1. Because of the large dispersion obtained
in both radial velocity and metallicity, we cannot be sure that we have sampled
true cluster members.Comment: 10 pages, 5 figures, accepted for publication in A&A (minor
modifications
Recruiting, interviewing, and hiring qualified individuals in an expanding dairy
This information was part of the August 2012 issue of Eastern DairyBusiness Magazine. The Manager, a section within the Eastern DairyBusiness Magazine, is authored and organized by the PRO-DAIRY program in the College of Agriculture and Life Sciences at Cornell University
Unveiling the Links between ICTs & Climate Change in Developing Countries: A Scoping Study
Secado natural de yuca para la alimentacion animal: Una nueva agroindustria en Colombia
A collaborative project of the Colombian Integrated Rural Development Program (DRI) and CIAT, aimed at establishing small agroindustrial firms to produce dry cassava on the Atlantic Coast of Colombia, is described. It began with the installation of a pilot plant for natural drying of cassava, with the collaboration of a group of 15 farmers. This plant operated on an exptl. basis in 1981 to obtain information about the efficiency of the process under the conditions existing on the Colombian Atlantic Coast and to determine the product`s acceptability by the animal feed industry. In 1982, during the project`s 2nd phase, the pilot plant was operated semicommercially to obtain data on production costs; likewise, it showed the economical and technical feasibility of the process. In 1983, the 3rd phase began, consisting in the replication of the project in other cassava-producing areas of the region. In 1984 and 1985, the project grew considerably, with 20 drying plants functioning in 1984 and 36 in 1985. To establish small-scale natural cassava drying plants, the following requisites are essential: (1) selection of a processing technology that can be assimilated, controlled, and easily managed by farmers; (2) implementation of integrated programs of processing, production, and commercialization that reduce the risks and increase net incomes of farmers; and (3) provision of institutional support that is adequate in terms of technical assistance, credit facilities, management and fiscal training, and of advice in the formation and consolidation of cooperative and associative groups for agricultural production. (AS-CIAT
Obtaining Au thin films in atmosphere of reactive nitrogen through magnetron sputtering
4d and 5d series of the transition metals are used to the obtaining nitrides metallic, due to the synthesis of PtN, AgN and AuN in the last years. Different nitrides are obtained in the Plasma Assisted Physics Vapour Deposition system, due to its ionization energy which is necessary for their formation. In this paper a Magnetron Sputtering system was used to obtain Au thin films on Si wafers in Nitrogen atmosphere. The substrate temperature was varied between 500 to 950°C. The samples obtained at high temperatures (>500°C) show Au, Si and N elements, as it is corroborated in the narrow spectrum obtained for X-Ray Photoelectron Spectroscopy; besides the competition of orientation crystallographic texture between (111) and (311) directions was present in the X-Ray Diffraction analysis to the sample heated at 950°C
II Workshop on Modeling and Simulation for Science and Engineering
II Workshop on Modeling and Simulation for Science and Engineering (II WMSSE) was a conference
conducted at Universidad Tecnológica de Bolívar, in the city of Cartagena de Indias, Colombia, on
September 24, 25 and 26, 2019. There, works in several topics of science, technology and engineering
were presented. Specially, the participants of conference wanted to bring some solutions to the actual
industrial requirements such as improvement and optimization of the heat transfer equipment, electronic
devices, system control by mean of computational modeling. Also, dynamic system control was widely
used for the prediction of power flow market, diffusion of bacteria in coffee production, stress
concentration in industrial machines, analysis of population dynamics, model of hydrological and
pluviometric networks, encryption for intercommunication of substation control centers, and others
Challenges in the Teaching Profession: A Look at Current Realities
The teacher personifies in himself a core edge in the entire educational framework, even when his work may go unnoticed, misunderstood, or undervalued. On him falls the inescapable responsibility of training in aspects, such as the scientific; but also the human, in order to progressively build a better society. Despite this, this profession involves a myriad of speculations and myths that distort the perception of the teacher’s work, condescending conjectures that little or nothing are adapted to the reality involved in practice. In this regard, this research aims to delve into and reveal the most significant realities that circumscribe the teaching profession, as an activity that goes beyond just teaching in classrooms. Teaching has endless activities, challenges, complexities, and realities that cannot be superimposed only with the staging that allows the transfer of knowledge. Thus, the study was approached under a qualitative-non-interactive methodological approach, with an exploratory scope and documentary research design. From this perspective, taking into account references related to the subject and conversations with teachers from different educational institutions in Latin American countries, eight premises were identified and discussed as realities of the teaching profession: Teaching profession and social recognition, Erosion of the positive perception of the profession, values vs. society, teaching and the media, precarious salaries, stress and work overload, decreasing role of the teacher, and silence of the teachers. The present investigation concluded, among other things, that there is a need to know in depth the specific elements that surround the realities of the teaching profession, thus avoiding the generation of epistemological conceptions that distort the appreciations of this job. In addition, it is important to highlight that the contribution of this research lies in explicitly collecting the realities of the teaching profession; making the caveat that until now no study with these characteristics have been found in the scientific literature.
Keywords: teaching profession, education, teaching myths, teaching realities, teaching challenges.
Resumen
El docente personifica en sí mismo una arista medular en todo el entramado educativo, aun cuando su labor pueda pasar desapercibida, incomprendida o infravalorada en la particularidad. obre él recae la ineludible responsabilidad de formar en aspectos, como el científico; pero también el humano, con la finalidad de construir progresivamente una mejor sociedad. A pesar de esto, S esta profesión envuelve un sinnúmero de especulaciones y mitos que distorsionan la percepción de labor del docente, condescendiendo conjeturas que poco o nada se adecuan a la realidad envuelta en la práctica. A este respecto, el propósito de esta investigación consistió en ahondar y develar las realidades −más significativas− que circunscriben la profesión docente, como una actividad que va más allá de sólo impartir clases en las aulas. La docencia, lejos de ser encasillada únicamente de esta manera, tiene un sinfín de actividades, retos, complejidades y realidades que no pueden ser superpuestas tan solo con la puesta en escena que permite la transferencia de conocimientos. Así, el estudio fue abordado bajo un enfoque metodológico cualitativo-no interactivo, con alcance de tipo exploratorio y diseño de investigación documental. Bajo esta perspectiva, tomando en cuenta referencias relacionadas con la temática y conversaciones con docentes de diferentes instituciones educativas en países de Latinoamérica, se identificaron y discutieron 8 premisas como realidades de la profesión docente: Profesión docente y reconocimiento social, Erosión de la percepción positiva de la profesión, Valores vs. Sociedad, Docencia y medios de comunicación, Precariedad de los salarios, Estrés y sobrecarga laboral, Protagonismo decreciente del docente, y silencio de los profesores. La presente investigación concluyó entre otras cosas, que existe la necesidad de conocer a profundidad los elementos concretos que envuelven las realidades de la profesión docente, evitando así la generación de concepciones epistemológicas que distorsionan las apreciaciones sobre esta labor. Además, resulta importante resaltar que, el aporte de la presente investigación radica en recoger de forma explícita las realidades de la profesión docente; haciendo la salvedad que en la literatura científica no se encuentra hasta el momento un estudio con estas características.
Palabras Clave: profesión docente, educación, mitos docentes, realidades docentes, desafíos docentes
Prevalencia de trematodes y factores de riesgo asociados con el ganado lechero en Colombia
This study was conducted to establish the prevalence and identify the risk factors associated with trematode infections in dairy cattle in the Boyacá Highlands, Colombia. Fecal samples collected from 300 randomly selected cattle were examined using a simple sedimentation technique for differential trematodes egg count. The animals were found shedding eggs of three groups of trematodes, namely Fasciola hepatica, Paramphistomum cervi and Cotylophoron cotylophorum. The specific prevalence of this trematodes were 11.6%, 9.3%, and 3.7% respectively. A substantial overlap was observed in the appearance of F. hepatica y P. cervi. The prevalence of the three trematodes identified in this study was significantly associated (p<0.05) with body condition and breed, while the prevalence of Fasciola hepatica and Paramphistomum cervi, was associated with age. The prevalence of the three main trematodes of importance for animal health with a high rate of mixed infection along with a poor body condition, suggests a substantial economic loss incurred due to reduced productivity of livestock in the study area.El estudio se llevó a cabo para establecer la prevalencia e identificar los factores de riesgo asociados con las infecciones por trematodes en ganado lechero de las tierras altas de Boyacá, Colombia. Las muestras fecales recogidas de 300 bovinos seleccionados al azar se examinaron utilizando una técnica de sedimentación simple para el recuento diferencial de huevos de trematodes. En el ganado estudiado fueron encontrados huevos de tres grupos de trematodes, a saber: Fasciola hepatica, Paramphistomum cervi y Cotylophoron cotylophorum. La prevalencia específica para estas tres especies fueron de 11,6%, 9,3% y 3,7% respectivamente. Se observó una superposición importante entre F. hepatica y P. cervi. La prevalencia de los tres trematodes identificados en este estudio se asoció significativamente (p<0,05) con la condición corporal y la raza, mientras que la prevalencia de Fasciola sp y Paramphistomum sp fue asociada con la edad. La prevalencia de los tres principales trematodes de importancia para la salud animal y la alta tasa de infección mixta, junto al deterioro de la condición corporal, determinan una pérdida económica sustancial debida a la reducción de la productividad del ganado en el área estudiada
AuNx stabilization with interstitial nitrogen atoms: A Density Functional Theory Study
Researchers have been studying 4d and 5d Series Transition Metal Nitrides lately as a result of the experimental production of AuN, PtN, CuN. In this paper, we used the Density Functional Theory (DFT) implementing a pseudopotential plane-wave method to study the incorporation of nitrogen atoms in the face-centered cube (fcc) lattice of gold (Au). First, we took the fcc structure of gold, and gradually located the nitrogen atoms in tetrahedral (TH) and octahedral (OH) interstitial sites. AuN stabilized in: 2OH (30%), 4OH and 4TH (50%), 4OH - 2TH (close to the wurtzite structure) and 6TH (60%). This leads us to think that AuN behaves like a Transition Metal Nitride since the nitrogen atoms look for tetrahedral sites. © Published under licence by IOP Publishing Ltd
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