Browsing Ciencias básicas by Title
Now showing items 2310-2329 of 3100
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QA Programme of the TLD laboratory of the University of Costa Rica: IEC 61066 testing
(2008)The Thermoluminescence Personal Dosimetry Laboratory of the University of Costa Rica provides dose measurements for around 90% of occupational radiation workers in the country. The assessment of doses to workers routinely ... -
Quadratic Hamiltonians in phase-space quantum mechanics
(1989-07)The dynamical evolution is described within the phase-space formalism by means of the Moyal propagator, which is the symbol of the evolution operator. Quadratic Hamiltonians on the phase space are distinguished in that ... -
Quadratic variation for cylindrical martingale-valued measures
(2023)This article focuses in the definition of a quadratic variation for cylindrical orthogonal martingale-valued measures defined on Banach spaces. Sufficient and necessary conditions for the existence of such a quadratic ... -
Quantitation of myonecrosis induced by myotoxin a from prairie rattlesnake (Crotalus viridis viridis) venom
(1982)Using a pure myotoxin (myotoxin a) isolated from prairie rattlesnake Crotalus viridis viridis) venom, a comparison between two methods for quantitating myonecrosis in mice was made. Measurement of creatine kinase (CK) ... -
Quantitative genetic analysis of anxiety trait in bipolar disorder
(2017)Background:Bipolar disorder type I (BPI) affects approximately 1% of the world population. Although geneticinfluences on bipolar disorder are well established, identification of genes that predispose to the illness has ... -
Quantitative Physiology Approaches to Understand and Optimize Reducing Power Availability in Environmental Bacteria
(2015-06-04)The understanding of how carbon fluxes are distributed through a metabolic network offers an overview of the pathways that a given microorganism uses to produce energy, reducing power, and biomass. These invaluable data ... -
Quantum electrodynamics in external fields from the spin representation
(1994-07)Systematic use of the infinite-dimensional spin representation simplifies and rigorizes several questions in quantum field theory. This representation permutes "Gaussian" elements in the fermion Fock space, and is necessarily ... -
Quantum ferroelectric instabilities in superconducting SrTiO3
(2018)We examine the effects of strain and cation substitution on the superconducting phase of polar semiconductors near a ferroelectric quantum phase transition with a model that combines a strong coupling theory of ... -
Quantum gauge models without classical Higgs mechanism
(2010-09-15)We examine the status of massive gauge theories, such as those usually obtained by spontaneous symmetry breakdown, from the viewpoint of causal (Epstein-Glaser) renormalization. The BRST formulation of gauge invariance in ... -
Quantum symmetry groups of noncommutative spheres
(2001-08)We show that the noncommutative spheres of Connes and Landi are quantum homogeneous spaces for certain compact quantum groups. We give a general construction of homogeneous spaces which support noncommutative spin geometries. -
Quantum Theory of Triboelectricity
(2020-10-30)We propose a microphysical theory of the triboelectric effect by which mechanical rubbing separates charges across the interface between two materials. Surface electrons are treated as an open system coupled to two baths, ... -
Quenched distributions for the maximum, minimum and local time of the Brox diffusion
(2021)After leaving fixed the environment, which is called the quenchend case, we give explicitly the distribution function of the maximum and the minimum of the Brox diffusion at first time it reaches a barrier. We also give ... -
Quimica Orgánica Experimental
(1978)Los autores han tratado de reunir en este libro un conjunto de experimentos que permiten al profesor ejemplarizar todas las técnicas fundamentales del laboratorio de Química Orgánica y también ejemplarizar los compuestos ... -
Radionucleídos naturales y antropogénicos en el estuario del Golfo de Nicoya, Costa Rica
(2002)The activity of isotopes of the Uranium, and Thorium series (228Ac, 212Bi, 212Pb, 226Ra, 214Bi, 214Pb) as well as 40K and 137 Cs was monitored on sediment samples collected in the Gulf of Nicoya estuary (9 30 N 84 45 W), ... -
Rafael Francisco Osejo: ¿un hombre de ciencia de su época?
(2022)La construcción de las sociedades actuales ha sido posible gracias a los aportes de numerosos personajes a la política, a la economía, a las artes y a las ciencias. Considerado uno de los actores del proceso de independencia ... -
Ramphocelus passerinii alimentando pichones de Turdus grayi y notas sobre la reproducción de otras especies de Ramphocelus
(2015)En esta nota presentamos observaciones de un Ramphocelus passerinii alimentando juveniles de Turdus grayi. Además, ampliamos los registros de la época reproductiva para Ramphocelus costaricensis y Ramphocelus carbo. Esta ... -
Random Electric Field Instabilities of Relaxor Ferroelectrics
(2017-06-13)Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ... -
Range expansion and noteworthy records of Costa Rican birds (Aves)
(2018-01-19)We present new distribution information for 19 species of Costa Rican birds. Thirteen species show changes in altitudinal distribution, 9 are recorded at higher elevations such as Egretta rufescens (Gmelin, 1789), Heliomaster ... -
Range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833) (Anura, Bufonidae), from Costa Rica
(2020-06-02)We report the range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833), from tropical moist forests to tropical wet forests and towards southeastern Costa Rica. We evaluated erroneous reports of this ... -
Range extension for the Costa Rican Blindsnake, Amerotyphlops costaricensis (Jiménez & Savage, 1962) (Serpentes, Typhlopidae)
(2020-08-08)Amerotyphlops. costaricensis is difficult to observe in the field and is considered a rare species. There are fewer than ten individuals deposited in museum collections, representing roughly one population in both Nicaragua ...