Bounds on Lorentz Invariance Violation from MAGIC Observation of GRB 190114C.

On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification.

[Laboratory surveillance of measles. Chile, 1992-1995]. / Vigilancia de laboratorio en sarampión. Chile, 1992-1995.

BACKGROUND: The first massive national measles vaccination campaign in Chile was done in 1992. Since then a laboratory surveillance of the disease has been undertaken at the Instituto de Salud Pública. AIM: To report the results of laboratory surveillance of measles between 1992 and 1995. MATERIAL AND METHODS: Paired serum samples from suspected cases of measles were received at the Institute. Measles specific IgG was determined with indirect immunofluorescence methods. IgG and IgM immunoenzymatic methods were used as complementary techniques, and rubella infections were ruled out by hemmaglutination inhibition tests. RESULTS: Sera from 1087 presumptive cases (489 in 1992, 196 in 1993, 180 in 1994 and 222 in 1995) were analyzed. Only two cases of wild imported measles were confirmed, one in Arica in 1992 and the other in Santiago in 1993. Five additional post vaccine cases were detected. Eighty eight percent of samples in 1992 and 75% in 1994 were seropositive. A high percentage of cases were confirmed as rubella (55% in 1992 and 19% in 1994). CONCLUSIONS: Absence of wild measles virus circulation in Chile from 1992 to 1995 emphasizes the importance of laboratory surveillance of the disease.

[Seroepidemiologic study of measles in 2 populations of children under 10 years of age from the metropolitan area]. / Estudio seroepidemiológico del sarampión en dos poblaciones de niños menores de 10 años de edad del área metropolitana.

Measles antibodies were investigated by direct immunofluorescence in 274 samples from infants and 245 samples of children from 1 to 10 years of age. Antibodies were present in 74% of children under 3 months of age, decreasing to 42% at age 11 months. Positive results were obtained in 60% of children from 1 to 4 years of age, decreasing to 47% from 5 to 10 years of age. Overall, infants had 64% positive tests and children 54%. Accordingly, a greater susceptibility to infection by measles is found in infants above 3 months of age and children from 5 to 10 years of age.

[Immunity status of 2 Chilean female populations against rubella]. / Estado inmunitario contra la rubeola en dos poblaciones femeninas chilenas.

A total of 1248 females were studied to determine immunity against rubella. A higher socio-economic subgroup (n = 789) and a lower one (459) were defined. Inhibition of hemagglutination was used to detect immunity. Positive results were obtained in 95% of females and no differences were detected for both groups. 78% of positive titers fell in the dilution range 1:20 to 1:80.