1,753 research outputs found
Notes on Oscillator-Like Interactions of Various Spin Relativistic Particles
The equations for various spin particles with oscillator-like interactions
are discussed in this talk. Contents: 1. Comment on "The Klein-Gordon
Oscillator"; 2. The Dirac oscillator in quaternion form; 3. The Dirac-Dowker
oscillator; 4. The Weinberg oscillator; 5. Note on the two-body Dirac
oscillator.Comment: LaTeX file, 12 pp. Talk given at the Second Workshop "Osciladores
Arm\'onicos". Cocoyoc, M\'exico, March 23-25, 1994. To be published in NASA
Conference Proceedings. Preprint IFUNAM FT-94-44, EFUAZ-94-0
Shocks in relativistic transverse stratified jets, a new paradigm for radio-loud AGN
The transverse stratification of active galactic nuclei (AGN) jets is
suggested by observations and theoretical arguments, as a consequence of
intrinsic properties of the central engine (accretion disc + black hole) and
external medium. On the other hand, the one-component jet approaches are
heavily challenged by the various observed properties of plasmoids in radio
jets (knots), often associated with internal shocks. Given that such a
transverse stratification plays an important role on the jets acceleration,
stability, and interaction with the external medium, it should also induce
internal shocks with various strengths and configurations, able to describe the
observed knots behaviours. By establishing a relation between the transverse
stratification of the jets, the internal shock properties, and the multiple
observed AGN jet morphologies and behaviours, our aim is to provide a
consistent global scheme of the various AGN jet structures. Working on a large
sample of AGN radio jets monitored in very long baseline interferometry (VLBI)
by the MOJAVE collaboration, we determined the consistency of a systematic
association of the multiple knots with successive re-collimation shocks. We
then investigated the re-collimation shock formation and the influence of
different transverse stratified structures by parametrically exploring the two
relativistic outflow components with the specific relativistic hydrodynamic
(SRHD) code AMRVAC. We were able to link the different spectral classes of AGN
with specific stratified jet characteristics, in good accordance with their
VLBI radio properties and their accretion regimes.Comment: 16 pages, 12 figures, accepted for publication in A&
Mister Morton, Stop Your Courtin\u27 / music by Frederick V. Bowers; words by Charles Horwitz
Cover: drawing of a woman peering from behind a tree; photo inset of The Nichols Sisters; Publisher: Sol Bloom (Chicago)https://egrove.olemiss.edu/sharris_b/1025/thumbnail.jp
Molecular Hydrogen Formation on Ice Under Interstellar Conditions
The results of experiments on the formation of molecular hydrogen on low
density and high density amorphous ice surfaces are analyzed using a rate
equation model. The activation energy barriers for the relevant diffusion and
desorption processes are obtained. The more porous morphology of the low
density ice gives rise to a broader spectrum of energy barriers compared to the
high density ice. Inserting these parameters into the rate equation model under
steady state conditions we evaluate the production rate of molecular hydrogen
on ice-coated interstellar dust grains.Comment: 20 pages, 3 tables and 10 figures. Accepted to ApJ. Minor changes
made and adittional references adde
Measurement of the Kinetic Energy of Hydrogen Molecules Desorbing from Amorphous Water Ice
A hydrogen molecule that is formed on an interstellar grain might retain some of the 4.48 eV of energy that is released in the recombination reaction of two hydrogen atoms. We set up an experiment to measure the translational (kinetic) energy of hydrogen molecules after they are formed on and are ejected from the surface of an interstellar dust grain analog. Here we report the first measurements of the kinetic energy of molecular deuterium as it leaves the surface of an amorphous water sample. The astrophysical implications of such measurements are discussed
La evaluación en la gestión pedagógica con la incorporación de las TIC-TAC- TEP
The present study is about Evaluation in Pedagogical Management as one of the major challenges that the educational environment has suffered. Due to the acceleration of the development of information and communication technologies, the incorporation of the concept of technologies of learning and knowledge; And empowerment for participation known as ICTs, TACs and TEPs. These guarantee in learning significant skills in students for the production of knowledge. Therefore, the evaluation, incorporating technology, aims to observe the ability of the student to organize, interpret knowledge, experiences and personal needs at a level that helps to use the new information to revise the new understanding of the world. It is approaching the pedagogical management for the planning and administration of the learning; Articulating strategically actions of the school environment in the educational processes and where the actors are immersed for interaction and exchange with society. The purpose is to contribute to the reflection that must be carried out continuously by the teacher from a set of theoretical references and highlight the shortcomings and aspects not resolved in the evaluation. The subject is developed from a documentary research in order to expand and deepen the knowledge that reflects the author's understanding and thinking in this working paper (UPEL, 2016). In addition, results of some researches explain the approach of the digital competences of the students of the 21st century for the change of evaluative culture in the contexts where this activity occurs. It is to reorient evaluation to new challengesEl presente producto en estudio trata sobre la Evaluación en la Gestión Pedagógica como uno de los mayores desafíos que ha sufrido el entorno educativo. Debido a la aceleración del desarrollo de las tecnologías de la información y comunicación, la incorporación del concepto tecnologías del aprendizaje y del conocimiento; y el empoderamiento para la participación conocida como las TIC, las TAC y las TEP. Estas garantizan en el aprendizaje habilidades significativas en los estudiantes para la producción del conocimiento. Por lo que la evaluación, al incorporar la tecnología, pretende observar la capacidad que tiene el estudiante para organizar, interpretar el conocimiento, las experiencias y las necesidades personales a un nivel que contribuya a utilizar la nueva información para revisar la nueva comprensión del mundo. Es aproximarse a la gestión pedagógica para la planeación y administración de los aprendizajes; articulando estratégicamente acciones propias del entorno escolar en los procesos educativos y donde están inmersos los actores para la interacción e intercambio con la sociedad. El propósito es contribuir a la reflexión que debe realizar continuamente el docente a partir de un conjunto de referentes teóricos y poner en relieve las carencias y los aspectos no resueltos en la evaluación. El tema está desarrollado desde una investigación documental con el fin de ampliar y profundizar el conocimiento que refleja la comprensión y el pensamiento del autor en este papel de trabajo (UPEL, 2016). Además, resultados de algunas investigaciones, explican el acercamiento de las competencias digitales de los estudiantes del siglo XXI para el cambio de la cultura evaluativa en los contextos donde esta actividad ocurre. Consiste en reorientar la evaluación a nuevos retos.  
Evolución del pensamiento pedagógico como símbolo de reconocimiento
Education is one of the great pillars on which the building of human society rests, it has been the subject of debate throughout human history. Great thinkers, philosophers, pedagogues, psychologists, economists and politicians have written and pronounced on how the educational system of a nation or a society should be directed and how it should be taught to children and other people. In this historical evolution, the traditional school model and the new school model have stood out. Each of these models has defenders and detractors. Each one seeks to highlight the benefits of each system or, on the contrary, criticize its shortcomings. This has led to the emergence of various pedagogical approaches that for a time seem to be the panacea to the structural and functional problems of the teaching - learning processes, to end, decaying and losing importance and be replaced by a new educational paradigm, due to the bombing permanent information and technological explosion that are hampering and closing the space for reflection and free decision-making, with awareness of what we want and the limitations and needs that restrict us. On the other is language as a means to understand the subject through communication and transform realities from a pedagogical thought as a sign of recognition. Therefore, the purpose of the essay is to review pedagogical approaches and their language in education by recognizing the epistemological heritage and its contribution to strengthening educational work with its particularities, nuances and characteristics that distinguish it.
La educación es uno de los grandes pilares sobre los cuales descansa el edificio de la sociedad humana, ha sido tema de debate durante toda la historia humana. Grandes pensadores, filósofos, pedagogos, psicólogos, economistas y políticos han escrito y se han pronunciado sobre la forma como debe dirigirse el sistema educativo de una nación o de una sociedad y como debe enseñarse a los niños y demás personas. En este devenir histórico han destacado el modelo de escuela tradicional y el modelo de escuela nueva. Cada uno de estos modelos tiene defensores y detractores. Cada uno busca resaltar las bondades de cada sistema o por el contrario criticar sus falencias. Ello ha dado lugar al surgimiento de diversos enfoques pedagógicos que por un tiempo parecen ser la panacea a los problemas estructurales y funcionales de los procesos enseñanza - aprendizaje, para terminar, decayendo y perdiendo importancia y ser remplazados por un nuevo paradigma educativo, debido al bombardeo permanente de información y la explosión tecnológica que van dificultando y cerrando el espacio para la reflexión y la toma de decisiones libre, con conciencia de los que queremos y de las limitaciones y necesidades que nos restringen. Por el otro se encuentra el lenguaje como medio para comprender al sujeto a través de la comunicación y transformar realidades desde un pensamiento pedagógico como signo de reconocimiento. Por lo que, el propósito del ensayo es revisar los planteamientos pedagógicos y su lenguajear en la educación reconociendo el acervo epistemológico y su contribución al fortalecimiento del quehacer educativo con sus particularidades, matices y características que la distinguen
Opportunities and challenges for pig production in Vientiane Capital, Laos: a review
In Laos, pork is the second most common meat source after fish and its demand is constantly growing annually. Recently, pork has been in short supply in urban and rural areas, forcing the Lao government to import thousands of tons from neighbouring countries, particularly Thailand, Vietnam, and China. In view of the earlier-mentioned, this study aimed to look at the current situation of pork production and supply in Vientiane Capital (VC) and the prospects for pork production in VC, Laos. In 2020, Laos had a pig population of about 4.3 million, with over 91.0 % being native pigs and only 366,000 heads being European pig types, with over 54.0 % being reared in VC. In 2019, Laos had 578 commercial pig farms, with 188 farms (33.0 %) of which were located in VC. Despite the fact that most of the commercial pig farms are located in VC, pork demand is still high, with the consequence that consumers need to pay a high price. For example, in 2020, the average price of pork was 46,000 LAK/kg ($ 4.00); it rose up by 22.0 % against 2019 and by 11.0 % from 2015. Several feed raw materials (maize, cassava, and rice bran) are produced in VC, and nearby provinces, which the farmers can use to combat the dramatic changes or instabilities of feed price. We concluded that there is a high potential to develop pig production in VC, especially local breeds considering the high demand for premium pork and more available raw feed materials
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