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.

Pseudohiperkalemia por trombocitosis esencial: una entidad pobremente reconocida / Pseudohyperkalaemia in essential thrombocytosis: a poorly recognized

INTRODUCCIÓN: La hiperkalemia representa una emergencia médica frecuentemente manejada en servicios de urgencia. Identificar una pseudohiperkalemia en pacientes que presentan recuentos plaquetarios elevados permite evitar terapias innecesarias e iatrogenia que pueden tener consecuencias potencialmente fatales. PRESENTACIÓN DEL CASO: Mujer de 73 años, con enfermedad renal crónica (ERC) etapa-3a (etiología no precisada). En consulta neurológica por crisis isquémica transitoria (abril 2011), se demostró hiperkalemia de 6,0 mEq/L (suero), tasa de filtración glomerular(TFG) de 51 mL/min y trombocitosis de 1.113.000 plaquetas/mm3. Se trata la hiperkalemia con furosemida y dieta pobre en potasio. Inició hidroxiurea indicada por hematología. En control nefrológico (diciembre 2012) presenta hiperkalemia de 7,5 mEq/L (suero), TFG de 37 ml/min y trombocitosis de 1.052.000 plaquetas/mm3. Electrocardiograma (ECG), sin signos de cardiotoxicidad acordes al nivel de kalemia. Se sospechó pseudohiperkalemia secundaria a trombocitosis esencial (PSTE), se suspendió atenolol, furosemida y se continuó hidroxiurea. En febrero de 2013 presentó kalemia de 6,1 mEq/L (suero), trombocitosis de 713.000 plaquetas/mm3 y TFG de 31 mL/min. En mayo de 2014 la kalemia en suero fue de 5,5 mEq/L y en plasma de 5,2 mEq/L; trombocitosis de 503.000plaquetas/mm3 y TFG de 23 ml/min, confirmándose la PSTE. DISCUSIÓN: Hiperkalemia asociada a trombocitosis exige descartar PSTE. La regresión de la kalemia junto con la trombocitosis y ECG sin alteraciones en hiperkalemia, apoyan este diagnóstico. Su confirmación exige demostrar una hiperpotasemia mayor en suero que en plasma (0,36 +/-0,18 meq/L). Tratar una pseudohiperkalemia, puede generar iatrogenia (hipokalemia y/o hemoconcentración que aumenta riesgo de trombosis). Se descarta hiperkalemia secundaria a ERC con TFG>15ml/min

INTRODUCTION: Hyperkalemia is a medical emergency often managed in emergency services. Identifying a pseudohiperkalemia in patients with high platelet counts will avoid unnecessary iatrogenic therapies, which can have potentially fatal consequences. CASE REPORT: 73 year old woman, with chronic kidney disease (CKD) stage-3a (unknown etiology). In neurological consultation by transient ischemic attack (april 2011) it was evidenced a hyperkalemia of 6.0 mEq/L (serum), glomerular filtration rate (GFR) of 51 mL/min and thrombocytosis of 1,113,000 platelets/mm3. Hyperkalemia is treated with furosemide and potassium poor diet. Started on hydroxyurea indicated by hematology. Nephrology consultant (december 2012) realized hyperkalemia of 7.5 mEq/L (serum), GFR of 37mL/min and thrombocytosis of 1,052,000 platelets/mm3. EKG with no sign of cardiotoxicity was found in relation to potassium serum level. A pseudohyperkalemia secondary to essential thrombocytosis (PSET) was suspected. Atenolol and furosemide were discontinued and hidroxiurea was continued. In February 2013 potassium serum level was 6.1 mEq/L, platelet count: 713,000/ mm3 and GFR: 31 mL/min. In may 2014 serum potassium was 5.5 mEq/L and plasma potassium was 5.2 mEq/L; platelet count: 503,000//mm3 and GFR: 23 mL/min, confirming PSET. DISCUSSION: Hiperkalemia associated with thrombocytosis requires to rule out PSET. Regression of serum potassium with platelet count and the abscense of EKG changes with simultaneous hyperkalemia, support this diagnosis. Confirmation of PSTE diagnosis needs to demonstrate a potassium serum level greater than in plasma (0.36 +/- 0.18 mEq/L). Treating a pseudohiperkalemia can generate iatrogenia (hypokalemia and/or hemoconcentration, increasing the risk of thrombosis). A hyperkalemia secondary to CKD is ruled out with GFR >15mL/min

The rapid formation of a large rotating disk galaxy three billion years after the Big Bang.

Observations and theoretical simulations have established a framework for galaxy formation and evolution in the young Universe. Galaxies formed as baryonic gas cooled at the centres of collapsing dark-matter haloes; mergers of haloes and galaxies then led to the hierarchical build-up of galaxy mass. It remains unclear, however, over what timescales galaxies were assembled and when and how bulges and disks--the primary components of present-day galaxies--were formed. It is also puzzling that the most massive galaxies were more abundant and were forming stars more rapidly at early epochs than expected from models. Here we report high-angular-resolution observations of a representative luminous star-forming galaxy when the Universe was only 20% of its current age. A large and massive rotating protodisk is channelling gas towards a growing central stellar bulge hosting an accreting massive black hole. The high surface densities of gas, the high rate of star formation and the moderately young stellar ages suggest rapid assembly, fragmentation and conversion to stars of an initially very gas-rich protodisk, with no obvious evidence for a major merger.