A dynamical measure of the black hole mass in a quasar 11 billion years ago.

Tight relationships exist in the local Universe between the central stellar properties of galaxies and the mass of their supermassive black hole (SMBH)1-3. These suggest that galaxies and black holes co-evolve, with the main regulation mechanism being energetic feedback from accretion onto the black hole during its quasar phase4-6. A crucial question is how the relationship between black holes and galaxies evolves with time; a key epoch to examine this relationship is at the peaks of star formation and black hole growth 8-12 billion years ago (redshifts 1-3)7. Here we report a dynamical measurement of the mass of the black hole in a luminous quasar at a redshift of 2, with a look back in time of 11 billion years, by spatially resolving the broad-line region (BLR). We detect a 40-µas (0.31-pc) spatial offset between the red and blue photocentres of the Hα line that traces the velocity gradient of a rotating BLR. The flux and differential phase spectra are well reproduced by a thick, moderately inclined disk of gas clouds within the sphere of influence of a central black hole with a mass of 3.2 × 108 solar masses. Molecular gas data reveal a dynamical mass for the host galaxy of 6 × 1011 solar masses, which indicates an undermassive black hole accreting at a super-Eddington rate. This suggests a host galaxy that grew faster than the SMBH, indicating a delay between galaxy and black hole formation for some systems.

[Use of ranitidine in children's before and after an educative intervention with resident's in a third level pediatric hospital]. / Uso de ranitidina en niños antes y despuésde una intervención educativa en residentes de un hospital pediátrico de tercer nivel.

BACKGROUND: The H2-receptor blockers are often prescribed, but its good tolerance and accessibility have contributed to the abuse of these drugs. The lack of medical knowledge of the precise use of ranitidine involves a higher cost of care and possible errors. OBJECTIVE: To evaluate the use of ranitidine in a pediatric hospital of third level before and after an educational intervention for medical residents. MATERIALS AND METHODS: We reviewed 240 clinical files, taken at random from hospital wards, excluding emergency room and intensive care unit. The correct indications and the precise dose of the drug were verified. Ninety-three medical residents of each grade of the Pediatric residency were evaluated with an initial survey (IS). Each resident was handed a document with the indications,dosage of medicine and pharmacology. A month later, a second survey (SS) to the medial resident and clinical file was performed. RESULTS: The justified indication of ranitidine increased from 52.1 to 66.6% and not justified fell from 47.8 to 33.3%, the error in the prescription increased from 10.8 to 19.0% in the (SS) despite the educational intervention. CONCLUSION: The educational intervention on residents decreased prescribing of the drug when it is not justified; however more training and assistance to doctors and nurses is needed to avoid errors in prescribing and to prevent adverse effects.