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1.
Phys Rev Lett ; 131(5): 051201, 2023 Aug 04.
Article in English | MEDLINE | ID: mdl-37595214

ABSTRACT

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1 TeV)^{-γ}, with A=(1.6±0.3)×10^{-12} TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

2.
Rev. mex. ing. bioméd ; 42(1): e1110, Jan.-Apr. 2021. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1156801

ABSTRACT

ABSTRACT A new coronavirus denominated first 2019-nCoV and later SARS-CoV-2 was found in Wuhan, China in December of 2019. This paper compares three mathematical methods: nonlinear regression, SIR, and SEIR epidemic models, to track the covid-19 disease in nine countries affected by the SARS-CoV-2 virus, to help epidemiologists to know the disease trajectory, considering initial data in the pandemic, mainly 100 days from the beginning. To evaluate the results obtained with the three methods one-way ANOVA is applied. The average of predicted infected cases with SARS-CoV-2, obtained with the mentioned methods was: for United States of America 1,098,508, followed by Spain with 226,721, Italy with 202,953, France with 183,897 United Kingdom with 182,190, Germany with 159,407, Canada with 58,696, Mexico with 50,366 and Argentina with 4,860 in average. The one-way ANOVA does not show a significant difference among the results of the projected infected cases by SARS-CoV-2, using nonlinear regression, SIR, and SEIR epidemic methods. The above could mean that initially any method can be used to model the pandemic course.


RESUMEN Un nuevo coronavirus denominado primero 2019-nCoV y más tarde SARS-CoV-2 fue encontrado en Wuhan, China en diciembre de 2019. El objetivo de este trabajo es comparar tres métodos matemáticos: regresión no lineal, modelos epidemiológicos SIR y SEIR, para rastrear la enfermedad del COVID-19 en nueve países infectados por el virus SARS-CoV-2, con el propósito de ayudar al epidemiólogo a conocer el curso de la pandemia, considerando principalmente sus primeros 100 días. Para evaluar los resultados obtenidos de la aplicación de los tres métodos, se aplicó ANOVA de una vía. El número promedio de casos infectados con SARS-CoV-2, obtenidos con los tres métodos descritos son: para Estados Unidos 1,098,508, seguido de España con 226,721, Italia con 202,953, Francia con 183,897 Reino Unido con 182,190, Alemania con 159,407, Canadá con 58,696, México con 50,366 y Argentina con 4,860 en promedio. El ANOVA de una vía no muestra diferencias significativas entre los resultados de los casos infectados proyectados por SARS-CoV-2, utilizando la regresión no lineal y los métodos SIR and SEIR. Lo anterior podría señalar que cualquiera de los tres métodos estudiados puede modelar el curso de la pandemia en las condiciones descritas para cada uno.

3.
Ginecol Obstet Mex ; 64: 490-7, 1996 Nov.
Article in Spanish | MEDLINE | ID: mdl-9091425

ABSTRACT

Clomiphene citrate (CC) induces framshift mutations on the Salmonella typhimurium Ames strains TA1538, TA97 and TA100 employing in vitro metabolic activation with S9 aerochlor 1254 induced rat livers, but not base pair substitution mutations with neither the standard or the preincubation method. CC induced genolethal DNA damages on the Escherichia coli PolA-/PolA+ with S9 on the preincubation method or without S9 on the disk diffusion one. The severe primary DNA damages produced b CC was verified by the SOS induction on the lysogenic lambda phage induction with De Marini (1988) method and the induction of colicin E1 plasmid on E. coli. These results are suggestive that CC may be an adduct forming compound which is able to inhibit replication if the cell lacks DNA polymerase, or it may produce framshift mutations after replications. CC induced damages could be large lesions conducing to unicatenary DNA strains, that are able to induce the lexA regulated genes. So, the use of this ovulation inductor is a risk of genotoxic damage and it is advisable to do a risk-benefit evaluation in any particular case before its prescription.


Subject(s)
Clomiphene/toxicity , Fertility Agents, Female/toxicity , Escherichia coli/drug effects , Escherichia coli/genetics , Mutagenicity Tests , Mutation , Risk Assessment , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics
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