The accretion disk in the post period-minimum cataclysmic variable SDSS J080434.20+510349.2

This study of SDSS0804 is primarily concerned with the double-hump shape in the light curve and its connection with the accretion disk in this bounce-back system. Time-resolved photometric and spectroscopic observations were obtained to analyze the behavior of the system between superoutbursts. A geometric model of a binary system containing a disk with two outer annuli spiral density waves was applied to explain the light curve and the Doppler tomography. Observations were carried out during 2008-2009, after the object's magnitude decreased to V~17.7(0.1) from the March 2006 eruption. The light curve clearly shows a sinusoid-like variability with a 0.07 mag amplitude and a 42.48 min periodicity, which is half of the orbital period of the system. In Sept. 2010, the system underwent yet another superoutburst and returned to its quiescent level by the beginning of 2012. This light curve once again showed a double-humps, but with a significantly smaller ~0.01mag amplitude. Other types of variability like a "mini-outburst" or SDSS1238-like features were not detected. Doppler tomograms, obtained from spectroscopic data during the same period of time, show a large accretion disk with uneven brightness, implying the presence of spiral waves. We constructed a geometric model of a bounce-back system containing two spiral density waves in the outer annuli of the disk to reproduce the observed light curves. The Doppler tomograms and the double-hump-shape light curves in quiescence can be explained by a model system containing a massive >0.7Msun white dwarf with a surface temperature of ~12000K, a late-type brown dwarf, and an accretion disk with two outer annuli spirals. According to this model, the accretion disk should be large, extending to the 2:1 resonance radius, and cool (~2500K). The inner parts of the disk should be optically thin in the continuum or totally void.Comment: 12 pages, 15 figures, accepted for publication in A&

New records of hunting ants (Poneroids and Ectatomminoids) in the northern part of the Colombian Orinoquia region

Nous registres de formigues caçadores (Poneroides i Ectatomminoides) al nord de l’Orinòquia Colombiana. Es van revisar 466 espècimens de formigues caçadores recol·lectades en ambients de sabana inundable i boscos a la zona rural del municipi d’Arauca (Arauca, Colòmbia). En vuit zones de bosc amb grandàries de 0,25 a 220 ha es va situar un transsecte lineal amb set punts de mostreig separats per 20 m amb una superfície de 10 m2 cadascun. En cada punt de mostreig es van utilitzar tres tipus de tècniques: una trampa de caiguda per 24 hores, una mostra d’1 m2 de fullaraca processada en sac mini Winkler i la captura directa. Es van registrar 15 espècies, entre les quals el gènere més divers va ser Neoponera, amb sis espècies, seguit d’Odontomachus, amb dues espècies i Ectatomma, Anochetus, Gnamptogenys,Prionopelta, Pseudoponera, Pachycondyla i Thaumatomyrmex, amb una sola espècie cadascun. En aquest estudi s’amplia la distribució geogràfica de 15 espècies per al nord de l’Orinòquia colombiana i es registra per primera vegada la presència de Thaumatomyrmex cf. mutilatus a Colòmbia. Dades publicades a GBIF i a SiB Colombia (doi: 10.15472/vp8v42).Nuevos registros de hormigas cazadoras (Poneroides y Ectatomminoides) en el norte de la Orinoquia Colombiana. Se revisaron 466 especímenes de hormigas cazadoras recolectadas en ambientes de sabana inundable y bosques en la zona rural del municipio de Arauca (Arauca, Colombia). En ocho zonas de bosque con tamaños de entre 0,25 y 220 ha se ubicó un transecto lineal con siete puntos de muestreo separados por 20 m con una superficie de 10 m2 cada uno. En cada punto de muestreo se utilizaron tres tipos de técnicas: una trampa de caída por 24 horas, una muestra de 1 m2 de hojarasca procesada en saco mini Winkler y la captura directa. Se registraron 15 especies siendo el género más diverso Neoponera, con seis especies, seguido de Odontomachus, con dos especies, y Ectatomma, Anochetus, Gnamptogenys, Prionopelta, Pseudoponera, Pachycondyla y Thaumatomyrmex, con una sola especie cada uno. En este estudio se amplía la distribución geográfica de 15 especies para el norte de la Orinoquia colombiana y se registra por primera vez la presencia de Thaumatomyrmex cf. mutilatus en  Colombia. Datos publicados en GBIF y en SiB Colombia (doi: 10.15472/vp8v42).We reviewed 466 specimens of hunting ant species collected in flooded savanna environments and their adjacent forest fragments in the rural area of Arauca municipality (Arauca, Colombia). Samples were taken from eight forest fragments with sizes between 0.25 and 220 ha. In each location we set linear transects with seven sampling points separated by 20 m. In each sampling point we used three capture methods: a pitfall trap (left 24 hours), a sample of 1m2 of soil and litter to be processed with a mini Winkler extractor, and direct capture. Fifteen species were recorded; the most diverse genus was Neoponera with six species, followed by Odontomachus with two species and Ectatomma, Anochetus, Gnamptogenys, Prionopelta Pseudoponera, Pachycondyla and Thaumatomyrmex each with one species. This study extends the geographical distribution of 15 hunting ant species to the northern part of the Colombian Orinoquia region and documents for the first time the presence of Thaumatomyrmex cf. mutilatus in Colombia. Data published through GBIF and SiB Colombia (doi: 10.15472/vp8v42)

Adverse events of ERCP at San José Hospital of Bogotá (Colombia)

Endoscopic retrograde cholangiopancreatography (ERCP) has become the preferred treatment method for hepatobiliary and pancreatic disease. Despite technological progress this technique continues to account for the greatest morbidity and mortality caused by digestive endoscopic procedures. ERCP carries a risk of pancreatitis, perforation, hemorrhage, cholangitis and cardiopulmonary events occurring in upto 10% of patients in referral centers, implying a mortality of up to 1%, not including therapeutic failures or the need for re-intervention. A greater mortality rate has been demonstrated in prospective studies rather than in retrospective studies, but overall, the number of complications described in the literature is much lower than the number of complications that actually occur. A descriptive prospective study was conducted at San José Hospital from April 1, 2006 to April 30, 2007 in patients who underwent an ERCP and had a 1-month follow-up. A total of 381 patients were included; 9 (2.3%) were excluded, and of the remaining 372 there was an overall success in 79.6% of cases, 8.3% had a second intervention, 7.6% developed complications (pancreatitis, perforation, hemorrhage, cholangitis, pain, intolerance to sedatives, and cardiopulmonary events), and 4.3% were failed ERCP studies. The mortality rate of the ERCP procedure was 0.8%. ERCP-related complications were determined at a teaching center, and this suggests the need to implement centers of excellence in order to improve the efficacy of the procedure