12,371 research outputs found

    A general nonconvex large deviation result II

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    We refine the conditions for the lower bound in an abstract large deviation result with nonconvex rate function we had previously introduced. We apply the results to certain stochastic recursive schemes.Comment: Published by the Institute of Mathematical Statistics (http://www.imstat.org) in the Annals of Probability (http://www.imstat.org/aop/) at http://dx.doi.org/10.1214/00911790400000044

    On the classical-quantum correspondence for the scattering dwell time

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    Using results from the theory of dynamical systems, we derive a general expression for the classical average scattering dwell time, tau_av. Remarkably, tau_av depends only on a ratio of phase space volumes. We further show that, for a wide class of systems, the average classical dwell time is not in correspondence with the energy average of the quantum Wigner time delay.Comment: 5 pages, 1 figur

    Basin structure in the two-dimensional dissipative circle map

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    Fractal basin structure in the two-dimensional dissipative circle map is examined in detail. Numerically obtained basin appears to be riddling in the parameter region where two periodic orbits co-exist near a boundary crisis, but it is shown to consist of layers of thin bands.Comment: published in J. Phys. Soc. Jpn., 72, 1943-1947 (2003

    Influencia del mucílago de cactus y extracto de algas pardas marinas en la resistencia a compresión y durabilidad del hormigón

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    This paper presents the mechanical performance and durability of concrete with water/cement (w/c) ratios of 0.30 and 0.60 containing cactus mucilage and brown marine seaweed extract solutions (at 0.5° Brix concentrations). Cylindrical specimens (100 mm x 200 mm) were cast and moist-cured for 0 and 28 days. Compressive strength, rapid chloride permeability, and chloride diffusion tests were conducted to evaluate all of the concrete mixes at the ages of 60 and 120 days. In addition, accelerated carbonation tests were carried out on specimens at the age of 180 days by exposure to 23 °C, 60% RH and at 4.4% CO2 for 120 days. The compressive strength results showed that only one concrete mix with admixtures increased in strength compared to the control. Regarding the rapid chloride permeability, chloride diffusion and carbonation, the results indicated that the durability of concretes containing organic additions was enhanced compared to the control.Este trabajo presenta el comportamiento mecánico y de durabilidad de concretos con relaciones agua/cemento de 0.30 y 0.60, conteniendo soluciones de mucílago de nopal y extracto de algas marinas cafés (0.5 °Brix de concentración). Especímenes cilíndricos (100 mm x 200 mm) fueron elaborados y curados en húmedo por 0 y 28 días. Se evaluó la resistencia a la compresión, permeabilidad rápida y difusión de cloruros a los 60 y 120 días de edad. Adicionalmente, se realizaron pruebas de carbonatación acelerada en especímenes con 180 días de edad, expuestos a 23 °C, 60% HR y 4.4% de CO2 por 120 días. Los resultados de resistencia a la compresión muestran que únicamente una mezcla de concreto con adición orgánica incrementó su resistencia con respecto al control. Con respecto a la permeabilidad rápida a cloruros, difusión de cloruros y carbonatación, los resultados indican que la durabilidad de los concretos que contenían adiciones orgánicas fue mejorada con respecto al control

    Oxidative stress is tightly regulated by cytochrome c phosphorylation and respirasome factors in mitochondria

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    Respiratory cytochrome c has been found to be phosphorylated at tyrosine 97 in the postischemic brain upon neuroprotective insulin treatment, but how such posttranslational modification affects mitochondrial metabolism is unclear. Here, we report the structural features and functional behavior of a phosphomimetic cytochrome c mutant, which was generated by site-specific incorporation at position 97 of p-carboxymethyl-l-phenylalanine using the evolved tRNA synthetase method. We found that the point mutation does not alter the overall folding and heme environment of cytochrome c, but significantly affects the entire oxidative phosphorylation process. In fact, the electron donation rate of the mutant heme protein to cytochrome c oxidase, or complex IV, within respiratory supercomplexes was higher than that of the wild-type species, in agreement with the observed decrease in reactive oxygen species production. Direct contact of cytochrome c with the respiratory supercomplex factor HIGD1A (hypoxia-inducible domain family member 1A) is reported here, with the mutant heme protein exhibiting a lower affinity than the wild-type species. Interestingly, phosphomimetic cytochrome c also exhibited a lower caspase-3 activation activity. Altogether, these findings yield a better understanding of the molecular basis for mitochondrial metabolism in acute diseases, such as brain ischemia, and thus could allow the use of phosphomimetic cytochrome c as a neuroprotector with therapeutic applications.España, Junta de Andalucía BIO-198España MINECO BFU2015-71017/BM

    On the infimum attained by a reflected L\'evy process

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    This paper considers a L\'evy-driven queue (i.e., a L\'evy process reflected at 0), and focuses on the distribution of M(t)M(t), that is, the minimal value attained in an interval of length tt (where it is assumed that the queue is in stationarity at the beginning of the interval). The first contribution is an explicit characterization of this distribution, in terms of Laplace transforms, for spectrally one-sided L\'evy processes (i.e., either only positive jumps or only negative jumps). The second contribution concerns the asymptotics of \prob{M(T_u)> u} (for different classes of functions TuT_u and uu large); here we have to distinguish between heavy-tailed and light-tailed scenarios

    Enfermedad viral por virus SARS -CoV2 en niños. Presentación de un caso

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    Introduction: In general, the affectation of the SARS-CoV2 virus in children is mild or asymptomatic, otherspresent symptoms that can be diverse, in some they require admission and others in a smaller percentage it isnecessary to enter intensive care, the symptoms, sometimes with Abdominal disorders join other frequentsymptoms of the disease that can be confused with other pathologies. Objective: To differentiate the clinical expressions of the SARS-CoV2 virus in the pediatric age, with otherviral infections. Material and methods: Retrospective descriptive study presenting a clinical case. Results: We present a case of an 8-year-old girl who did not present a cough in her symptoms and that thesymptoms of joint pain, headache, diarrhea, vomiting, high fever, were the fundamental in her clinical picture,these are also shared with Dengue , Elevated IgM 126 (0-0.99), CRP 4.05 mg / L (0-0.9), with mild neutrophilia82.5% (55-70) and lymphopenia 12.5% (17-45) were detected in the hematic biometry, Lactic Dehydrogenase(LDH) 232 U / L (100-190), normal electrolytes, Aspartate Amino Trasferase (TGO) 82 U / L (12-37), normal abdominal ECHO, negative dengue IgM, after 5 days of admission, of a remarkable improvementis discharged. Conclusions: Taking into account the incidence of Dengue in your place of residence, a differential diagnosiswith the SARS-CoV2 virus plays a fundamental role, because as this case shows us, it can have similar symptoms,so that an adequate clinical criterion and performance complementary, they will give us the opportunityto make a correct diagnosis.Introducción: En general la afectación del virus SARS -CoV2 en niños es leve o asintomática, otros presentansintomatología que puede ser diversa, en algunos requiere de ingreso y otros en un porciento menor es necesarioingresar en cuidados intensivos, la sintomatología, en ocasiones con trastornos abdominales se unen aotros síntomas frecuentes de la enfermedad que pueden ser confundidas con otras patologías. Objetivo: Diferenciar las expresiones clínicas del virus SARS -CoV2 en la edad pediátrica, con otras infeccionesvirales. Material y métodos: Estudio descriptivo retrospectivo presentación de caso clínico. Resultados: Presentamos un caso de una niña de 8 años que en su sintomatología no presentaba tos y que lossíntomas de dolores articulares, cefalea, diarreas, vómitos, fiebre elevada, eran lo fundamental en su cuadroclínico, estos también se comparten con el Dengue, se detectó IgM elevada 126 ( 0-0.99), PCR 4.05 mg/L(0-0.9), con una leve neutrofilia 82.5 % (55-70) y linfopenia 12.5% (17-45) en la biometría hemática, DeshidrogensaLáctica ( LDH) 232 U/L (100-190) , electrolitos normales, Aspartato Amino Trasferasa ( TGO) 82U/L ( 12-37), ECO abdominal normal, IgM dengue negativo, después de 5 días del ingreso, de una notablemejoría es dada de alta. Conclusiones: Teniendo en cuenta la incidencia del Dengue en su lugar de residencia juega un papel fundamentalrealizar el diagnostico diferencial con el virus SARS -CoV2, pues como este caso nos demuestra puedetener sintomatología similar, por lo que un criterio clínico adecuado y la realización de complementarios,nos darán la oportunidad de realizar un diagnóstico correct

    Geographic Range Expansion and Taxonomic Notes of the Shortfin Neoscopelid Neoscopelus cf. microchir (Myctophiformes: Neoscopelidae) in the North-Eastern Atlantic

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    One specimen of the shortfin neoscopelid Neoscopelus microchir Matsubara, 1943, has been recorded for the first time on the Porcupine Bank, southwestern Ireland, providing a new northern limit of distribution for the eastern Atlantic. Morphometric and meristic parameters confirm the taxonomic identification. However, DNA barcoding shows deficiencies in current taxonomy and the potential occurrence of cryptic species. On this basis, the specimen is cautiously reported as Neosopelus cf. microchir pending a taxonomic revision of the genus.Versión del edito
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