3,959 research outputs found
Socialización de experiencias de educación a nivel nacional de los departamentos y facultades de Ciencias básicas Bogotá-Colombia
La Universidad Manuela Beltrán buscó generar un espacio de socialización de experiencias de Educación en Ciencias Básicas, desde la formación científica, promoviendo la construcción de conocimiento, la reflexión continua y el diálogo entre saberes y prácticas, conducentes a la planificación de acciones al interior de las instituciones educativas que trasciendan al interior del aula. Se recibieron, analizaron y clasificaron por línea temáticas, sesenta y seis ponencias a nivel nacional. Con ello, se presenta así, una sistematización de con el objetivo de socializar a la comunidad académica los aspectos más relevantes de esta experiencia. Además de ofrecer como resultado los aprendizajes y parte de los análisis de las ponencias recibidas en el marco de este evento
Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator
A theoretical model of parametric magnetostrictive generator of ultrasound is
considered, taking into account magnetic and magnetoacoustic nonlinearities.
The stability and temporal dynamics of the system is analized with standard
techniques revealing that, for a given set of parameters, the model presents a
homoclinic or saddle--loop bifurcation, which predicts that the ultrasound is
emitted in the form of pulses or spikes with arbitrarily low frequency.Comment: 5 pages, 5 figure
Excitability in a nonlinear magnetoacoustic resonator
We report a nonlinear acoustic system displaying excitability. The considered
system is a magnetostrictive material where acoustic waves are parametrically
generated. For a set of parameters, the system presents homoclinic and
heteroclinic dynamics, whose boundaries define a excitability domain. The
excitable behaviour is characterized by analyzing the response of the system to
different external stimuli. Single spiking and bursting regimes have been
identified.Comment: 4 pages, 5 figure
Carrying rocks : Hoarding behaviour in the Gravettian occupation of Cova Gran de Santa Linya (SE Pyrenees)
Altres ajuts: Acord transformatiu CRUE-CSICCova Gran de Santa Linya is part of the project Human settlement during the Upper Pleistocene and Holocene in the Southeastern Pyrenees (PID 2019-104843GB-I00) and the 2017SGR-1357 research group. This research has been also supported by MINECO-FPU scholarships. Fieldwork was funded by Servei d'Arquelogia I Paleontologia from the Generalitat de Catalunya (CLT009/18/00012). We thank the support given by the Institute for Field Research, all volunteers that participate in the fieldwork, and the kind permission of the Societat de Munts de Santa Linya to authorize the excavation in Cova Gran.Lithic resources can be accumulated to form caches or hoards as an effective subsistence strategy in response to times of stress. Hoarding behaviour is the manifestation of foresighted mechanisms, and is one of the common and also little known strategies among forager groups. In this paper, we present the evidence of such behaviour: a deposit of raw material recovered from level 497C of the Cova Gran de Santa Linya (SE Pyrenees). The lithic hoard is made up of 27 chalcedony nodules that have been tested at the site and exhibit great variability in terms of size and shape. The geostatistical analysis applied to the accumulations of raw materials identified has allowed us to determine spatial relationships between different categories in the archaeological record, such as nodules and cores, and has yielded insight into the use of chalcedony in specific areas of the occupation. The archaeological data suggest that this stockpile of raw material functioned as small-scale storage, constituting one of the few references about hoarding behaviour during the Palaeolithic, and the first time it has been exhaustively described in the Gravettian on the Iberian Peninsula. The lithic hoard from the Cova Gran allows us to investigate the role played by raw material hoards in the planning of subsistence activities and the organisation of human occupations
Self-organization of ultrasound in viscous fluids
We report the theoretical and experimental demonstration of pattern formation
in acoustics. The system is an acoustic resonator containing a viscous fluid.
When the system is driven by an external periodic force, the ultrasonic field
inside the cavity experiences different pattern-forming instabilities leading
to the emergence of periodic structures. The system is also shown to possess
bistable regimes, in which localized states of the ultrasonic field develop.
The thermal nonlinearity in the viscous fluid, together with the
far-from-equilibrium conditions, are is the responsible of the observed
effects
Is there a pre-Cretaceous source rock in the Colombia Putumayo Basin? : clues from a study of crude oils by conventional and high resolution geochemical methods
A geochemical characterization of sixteen crude oil samples from the Putumayo Basin, southern Colombia, was carried out. This basin is located to the north of Ecuador's Oriente Basin, one of the most prolific hydrocarbon basins in South America. Regardless of the fact that these two basins seem to share the same geological evolution, the volume of hydrocarbon reserves found in the Oriente Basin is five times greater than in the Putumayo Basin. This represents an exploratory opportunity to the extent that a better understanding of the petroleum system processes in the Putumayo Basin can be achieved. Newly available geochemical technology shows evidence that these crude oils originated from Late Cretaceous source rocks. The novel application of an age-related biomarker, the C25-highly branched isoprenoid, has constrained the age of the principal source of all these oils as Late Cretaceous or younger. Advanced geochemical technologies, such as compound specific isotope analyses of biomarkers (CSIA-B) and diamondoids (CSIA-D), and quantitative extended diamondoid analysis (QEDA), have confirmed, repeatedly, that the oil samples are all related to the same source with minor facies variations. The integration of these results with geological data suggests the presence of a very efficient petroleum system, characterized by an alternating sequence of soçurce and reservoir rocks. Thermal maturity of the oils from biomarker and diamondoid parameters ranges from well before the peak of hydrocarbon expulsion to the beginning of the late hydrocarbon generation phase. The aerial distribution of these maturity parameters suggests the existence of two, or possibly three, pods of active source rocks, located to the southwest and to the east of the basin, and possibly to the north. This would modify the classic hydrocarbon migration model for the Putumayo Basin, increasing the hydrocarbon potential of the basin. Given the low level of thermal maturity documented in the Cretaceous sequence that has been drilled, the possibility to evaluate the presence of a very reactive kerogen with hydrocarbon expulsion thresholds at lower temperatures is proposed
Simple networks on complex cellular automata: From de Bruijn diagrams to jump-graphs
We overview networks which characterise dynamics in cellular automata. These
networks are derived from one-dimensional cellular automaton rules and global
states of the automaton evolution: de Bruijn diagrams, subsystem diagrams,
basins of attraction, and jump-graphs. These networks are used to understand
properties of spatially-extended dynamical systems: emergence of non-trivial
patterns, self-organisation, reversibility and chaos. Particular attention is
paid to networks determined by travelling self-localisations, or gliders.Comment: 25 pages, 14 figure
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