RESUMEN
Here, we report on the observation of a random to chaotic temperature transformation in the statistics of nearest-neighbor spacings of Fano-Feshbach resonances in the ultracold polarized gas of thulium-169 atoms. We associate this transformation to the appearance of so-called d resonances as well as the shift of other resonances with the temperature. In addition to this statistical change, it has been observed that the characters of s- and d-resonance temperature shifts are quite different: s resonances experience almost no shift or even negative shift with the temperature, while d resonances experience an obvious positive shift. The sign change was attributed to the difference in polarizability of Feshbach molecules and free thulium atoms. In addition, careful analysis of the broad Fano-Feshbach resonances enabled the determination of the sign of thulium's background scattering length. A rethermalization experiment made it possible to estimate a length value of a_{bg}=+144±38 a.u. This indicates that thulium atoms are suitable for achieving Bose-Einstein condensation.
RESUMEN
The paper considers effects of humic substances (HS), as natural attenuators of toxicity, on solutions of model inorganic pollutants, metal salts - Pb(NO(3))(2), СоСl(2), CuSO(4), Eu(NO(3))(3), СrСl(3), and K(3)[Fe(СN)(6)]. Luminous bacteria Photobacterium phosphoreum and bioluminescent system of coupled enzymatic reactions were used as bioassays to monitor toxicity of salt solutions. The ability of HS to decrease or increase toxicity was demonstrated. Detoxifying concentrations of HS were determined; detoxification coefficients were calculated at different times of exposure of salt solutions to HS. To study the combined effects of HS and salts on bioluminescent assay systems, the rates of biochemical reactions and bacterial ultrastructure were analyzed. The detoxifying effects were explained by: (1) decrease of free metal content in water solutions under metal-HS binding; (2) increase of biochemical reaction rates in a bioluminescent assay system under HS effect; (3) enhancement of mucous layers on cell surface as a response to unfavorable impact of toxicants. Detoxifying mechanisms (2) and (3) reveal the active role of bioassay systems in detoxification processes.
Asunto(s)
Contaminantes Ambientales/química , Contaminantes Ambientales/toxicidad , Sustancias Húmicas , Mediciones Luminiscentes/métodos , Metales/química , Sales (Química)/química , Sales (Química)/toxicidad , Bioensayo , Photobacterium/efectos de los fármacos , Photobacterium/ultraestructura , SolucionesRESUMEN
We have been studying association between distorted perception and visual event-related potentials, which appear in response to the Poggendorff figure's presentation in Jastrow modification. It was shown that the amplitude sign is determined by the presence or absence of subjective distortion at the earliest and the latest phase of Poggendorff figure's perception. The amplitude of the wave P150 was bigger at the distorted perception, and the amplitude of the waves N200 and P300 was smaller than during perception without distortion. It is suggested that both ascending nervous processes and cognitive processes of analysis are involved into the emergence of the Poggendorff illusion.
Asunto(s)
Potenciales Evocados Visuales , Ilusiones Ópticas , Reconocimiento Visual de Modelos , Adolescente , Electroencefalografía , Femenino , Humanos , Adulto JovenRESUMEN
Immunohistochemical verification of serotonin and of the vessels endothelial growth factor (VEGF) has enabled to establish the presence of these signaling molecules in human thymus in all stages of ontogenesis and in aging. Thus authentic increase of quantity of the cells synthesizing serotonin in people of advanced age is established, which reflects the compensatory role of serotonin, directed on maintenance of immunity in old organism. The minimum quantity of the cells containing VEGF is observed in human thymus of advanced age, but the intensity of synthesis of this peptide does not practically change during the postnatal ontogenesis. These data may be considered as the evidence of the important role of signaling molecules that are expressed in thymus in local paracrine regulation of thymic functions in aging.