3,985 research outputs found
noise and integrable systems
An innovative test for detecting quantum chaos based on the analysis of the
spectral fluctuations regarded as a time series has been recently proposed.
According to this test, the fluctuations of a fully chaotic system should
exhibit 1/f noise, whereas for an integrable system this noise should obey the
1/f^2 power law. In this letter, we show that there is a family of well-known
integrable systems, namely spin chains of Haldane-Shastry type, whose spectral
fluctuations decay instead as 1/f^4. We present a simple theoretical
justification of this fact, and propose an alternative characterization of
quantum chaos versus integrability formulated directly in terms of the power
spectrum of the spacings of the unfolded spectrum.Comment: 5 pages, 3 figures, RevTe
Caracterización de la estructura de las sustracciones en las que estudiantes universitarios cometen errores
La resolución correcta de las operaciones elementales es uno de los objetivos de la educación obligatoria en todo el mundo aunque no siempre se consigue (López y Sánchez, 2009). En concreto, referido a la sustracción, de los 535 estudiantes universitarios de la Universidad de Salamanca que completaron el cuestionario validado de 20 sustracciones de VanLehn (1990), sólo el 24’1% realizó correctamente todas las sustracciones (Rodríguez y Sánchez, 2015). En este trabajo se pretende analizar las características de las sustracciones en cuya resolución los estudiantes universitarios cometieron algún tipo de error
Garnet-clinopyroxene bearing assemblages in the 'upper catazonal unit' of the Cabo Ortega! Complex (NW Spain)
[Resumen] Se han estudiado los siguientes materiales de la 'unidad catazonal superior' del Complejo del Cabo Ortegal conteniendo asociaciones con granate-clinopiroxeno: eclogitas, granulitas básicas, intercalaciones gneísicas en las granulitas, piroxenitas con granate, gneises de la aureola de contacto de las rocas ultramáficas, metabasitas de la 'formación Candelaria' y 'carbonatitas'. Los datos termobarométricos obtenidos sugieren que, mientras que los minerales de algunos de estos materiales han sufrido importantes reajustes composicionales durante los procesos de retromorfosis (e. g. granulitas con distena, intercalaciones gneísicas en granulitas,
-intercalaciones u1tramáficas en gneises, etc.), otros han conservado elementos mineralógicos con la composición alcanzada durante el episodio metamórfico que originó la formación de las asociaciones con granate-clinopiroxeno. Este segundo grupo de materiales puede subdividirse en dos categorías: 1) aquellos materiales en los que la asociación granate-clinopiroxeno se formó en torno a los 800 oC y 15 ± 1. 5 kbar (eclogitas 'tipo-I', granulitas de la 'formación Bracariza', piroxenitas con granate de los macizos de rocas u1tramáficas 'carbonatitas'), y, 11)
aquellos en los que dicha asociaci6n se formó a unos 700 oC y la misma P aproximadamente
(eclogitas y granulitas intercaladas en las formaciones gneísicas). Aunque las diferencias no son muy importantes, es posible que los dos conjuntos litológicos representen dos gradientes metamórficos distintos y, por tanto, la existencia en dicha 'unidad' de materiales con diferentes historias tectono-metamórficas.[Abstract] The following materials from the 'uper' catazonal unit' of the Cabo Ortegal Complex, containing garnet-clinopyroxene assemblages, have been studied: eclogites, basic granulites, gneissic intercalations within granulites, garnetbearing pyroxenites, gneisses from the contact aureole of the ultramafic rocks, metabasites from the 'Candelaria formation' and 'carbonatites'. The thermobarometric data obtained from this study suggest that the minerals from several of those materials underwent strong compositional readjustements during the subsequent retromorphic events (e. g. the kyanite-bearing granulites, the gneissic intercalations in granulites, the u1tramafic intercalations in gneisses, etc.). The remaining materials have preserved mineral compositions attained during the metamorphic episode that produced the garnetclinopyroxene assemblages; these materials may be classified as follows: 1) those in which the garnet-clinopyroxene assemblage formed at ca. 800 oC and 15 ± ± 1,5 kbar ('type-I' eclogites, granulites from the 'Bacariza formation', garnetbearing pyroxenites from the ultramafic massifs and 'carbonatites'), and, 11) those where the same association developed at ca 700 oC and more or less the same P conditions (eclogites and granulites intercaled in gneisses). Although these differences in P and Tare not very important, it is possible that these two groups represent two different metamorphic gradients, and therefore the existence in this 'unit' of the Complex of two lithological sub-units with different tectono-metamorphic histories
Integral Field Spectroscopy of HH 262: The Spectral Atlas
HH 262 is a group of emitting knots displaying an "hour-glass" morphology in
the Halpha and [SII] lines, located 3.5' to the northeast of the young stellar
object L1551-IRS5, in Taurus. We present new results of the kinematics and
physical conditions of HH 262 based on Integral Field Spectroscopy covering a
field of 1.5'x3', which includes all the bright knots in HH 262. These data
show complex kinematics and significant variations in physical conditions over
the mapped region of HH 262 on a spatial scale of <3". A new result derived
from the IFS data is the weakness of the [NII] emission (below detection limit
in most of the mapped region of HH 262), including the brightest central knots.
Our data reinforce the association of HH 262 with the redshifted lobe of the
evolved molecular outflow L1551-IRS5. The interaction of this outflow with a
younger one, powered by L1551 NE, around the position of HH 262 could give rise
to the complex morphology and kinematics of HH 262.Comment: Accepted for publication in MNRA
Glassy dynamics, aging and thermally activated avalanches in interface pinning at finite temperatures
We study numerically the out-of-equilibrium dynamics of interfaces at finite
temperatures when driven well below the zero-temperature depinning threshold.
We go further than previous analysis by including the most relevant
non-equilibrium correction to the elastic Hamiltonian. We find that the
relaxation dynamics towards the steady-state shows glassy behavior, aging and
violation of the fluctuation-dissipation theorem. The interface roughness
exponent alpha approx 0.7 is found to be robust to temperature changes. We also
study the instantaneous velocity signal in the low temperature regime and find
long-range temporal correlations. We argue 1/f-noise arises from the merging of
local thermally-activated avalanches of depinning events.Comment: 4 pages, 4 figure
Índice de Liam: prueba física funcional
Made very important test (Liam) in the medical students in Medical Faculty in Artemisa city, because with this examination proof the functional and physical conditions before and after training. All students after training received best results than before. It is very important to because the students obtained some abilities in this subject when will be doctorsSe realizó un análisis de la prueba funcional de Liam en un grupo de estudiantes de 2do año de Medicina de Artemisa con el objetivo de valorar el grado de aptitud cardiovascular y el nivel de entrenamiento de este grupo, donde se obtuvo que la mayoría de los estudiantes el 77,8% estaba apto físicamente y solo dos para un 22,2% se encontraba en la categoría de pobre en la prueba que se realizó al inicio del curso .Esta prueba es de gran utilidad en nuestra formación como futuro Medico Generales Integrales y sobre todo que es muy fácil su proceder y lo podemos aplicar en área de salud con nuestros pacientes ,una vez graduados como médicos .En el mes de Abril después de seis meses de práctica sistemática de ejercicios físicos todos los estudiantes mejoraron de forma considerable su aptitud cardiovascular y el nivel de entrenamiento a las categorías de muy bien y bie
2D-Coordination polymers based on 1H-indazole4-carboxylic acid and transition metal ions: magnetic, luminescence and biological properties
We report the formation of five novel multifunctional coordination polymers based on 1H-indazole-4-
carboxylic acid (HL). To the best of our knowledge, these complexes are the first examples of coordination
compounds constructed with this interesting ligand. These materials were synthesized by solvothermal
routes, possess different 2D-structures and show interesting magnetic properties due to the copper
compound showing an unusual spin-canted effect while the anisotropic cobalt material behaves as a fieldinduced single molecule magnet. MTT assays performed on human embryonic kidney (HEK293) and
mouse skin melanoma (B16-F10) cell lines indicated that the Cd-based compound was the only one
exhibiting dose-dependent toxicity on B16-F10 cells, most likely due to the release of toxic Cd(II). Cadmium
and zinc polymers exhibit interesting luminescence properties. The fact that zinc polymers did not exhibit
inherent toxicity against both cancer and non-cancerous cells make this new family an excellent candidate
for further investigation in the field of luminescent materials with biomedical applications.Junta de Andalucia
FQM-394
FQM-1484Red Guipuzcoana de Ciencia, Tecnologia e Innovacion
OF218/2018University of Basque Country
GIU 17/13Basque Government
IT1005-16Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, UE)
PGC2018-102052-A-C22
PGC2018-102052-B-C21Junta de Andalucia
FQM-394
FQM-1484European Union (EU)ESFGovernment of the Basque CountryFEDER/MCIU/AEI
RYC-2016-21042
JdC-201
Correlaciones entre la infección por microquistes de S. lamacanis y CK-MB, Ast y LDH alpacas
El presente estudio tuvo objetivo determinar la correlación entre el número de microquistes de S. lamacanis en miocardio (N°Mq) y los niveles en sangre de las enzimas CK-MB, AST y LDH en alpacas, a fin de usarlos como predictores de salud o grado de infección por sarcocystiosis. Se utilizaron 41 alpacas de 3-5 años de edad del matadero Municipal Ninacaca, Pasco-Perú, las muestras de sangre se colectaron ante-mortem y las de miocardio post-mortem. El 100 % de los animales presentaron microquistes de S. Lamacanis, y los coeficientes de correlación entre el N°Mq y CK-MB fue de 0.17, AST 0.04 y para LDH 0.06. Se concluye que la correlación es muy baja o casi nula, por lo que las enzimas evaluadas no tendrían mayor importancia para determinar daño cardiaco por infección de microquistes de S. Lamacanis en alpacas
Characterization of ionic nature of biosurfactant extracted from corn steep liquor using ionic exchange resins
[Excerpt] Resins have been used for years for the purification and characterization of ionic substances. The use of these resins allows not only remove impurities or increase the concentration of metabolites from industrial streams, but also allows define their ionic structure. In general, surfactants can be classified as non-ionic, anionic, cationic or amphoteric, what is going to define their future application at industrial scale. For example, anionic surfactants present the greatest wetting and emulsifying properties, while cationic ones have excellent antibacterial properties as well as good emulsifier capacities. Otherwise, amphoteric surfactants, which may have anionic or cationic properties depending on pH, are widely used in personal care products because of their less irritability to skin and eyes in comparison with other types of surfactants. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904)University of Vigo (Spain
Potential applications of multifunctional extract obtained from corn industry in food packaging
[Excerpt] Nowadays, in the food industry exists an increased demand, by the consumers, of natural additives that can replace those chemical additives obtained from non renewable resources. In this work extracts with surfactant and antioxidant properties were obtained from corn steep liquor (CSl) with potential applications in food packaging. the extraction process was carried out using ethyl acetate and the operational conditions consisted of: CSl/ethyl acetate 1:3 (v/v), at 25°C during 45 min with agitation system at 150 rpm. the antioxidant activity of the extract was determined by the dPPh (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method; whereas the surface active properties was evaluated by the wilhelmy plate method in a force tensiometer with a platinum plate (easy dyne k20, kruSS gmbh), at room temperature. Fatty acid composition of extract was analyzed by gas chromatography coupled to a mass spectrometer (Bruker Scion 451-gC). [...
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