Seeing and weather observations were conducted at 5 sites within the boundaries of the area reserved for astronomy at the Sierra de San Pedro Mártir National Park (SPM), for at least 15 nights at each one of these. Weather variables were measured using a Davis Weather Station and a Metek Ultrasonic Anemometer. Seeing information was collected with a NOAO RoboDIMM unit. Seeing and weather results were compared to those being delivered at the same time by the instrumentation of the Thirty Meter Telescope Project at the Observatorio Astronómico Nacional (OAN) at SPM. Seeing differences are small in most cases. We recommend a long term campaign at the easily accessible site Llano Alto 1, where we found that seeing may be slightly better.

Realizamos mediciones climatológicas y de seeing, en 5 sitios dentro del área reservada para uso astronómico en el Parque Nacional Sierra de San Pedro Mártir (SPM), durante al menos 15 noches en cada uno de ellos. Las variables climáticas se midieron con una estación meteorológica Davis y un anemómetro ultrasónico Metek. El seeing fue medido con un RoboDIMM fabricado por NOAO. Las mediciones climatológicas y de seeing fueron comparadas con las obtenidas simultáneamente con la instrumentación del Thirty Meter Telescope Project en el Observatorio Astronómico Nacional (OAN) en SPM. Las diferencias de seeing son pequeñas en la mayor parte de los casos. Recomendamos que se realice una campaña de larga duración en Llano Alto 1, ya que es un sitio de fácil acceso y el seeing parece ser ligeramente mejor.

We compare simultaneous seeing measurements produced by the differential image motion monitor (DIMM) units used at the Observatorio Astronómico Nacional at San Pedro Mártir (SPD) and at Cerro Tololo Inter-American Observatory (RoD), for a total of 14 nights. For the data set, made of 1581 nearly-synchronous measurements, we find that the mean and median RoD-SPD seeing differences are +0.004±0.138" and +0.010" respectively. We also find that the median of the RoD-SPD seeing measurements is +0.041" when seeing is less than 1", -0.032" when it is between 1" and 1.5", and -0.292" when it is larger than 1.5". Since seeing is usually smaller than 1", we conclude that measurements obtained with SPD-like units should be increased by 0.01" to 0.04" when comparisons are made with sites using RoD-like units. This correction is much smaller than the natural dispersion of seeing measurements along any night, and it makes sense only when operational conditions in both sites are practically the same.

Comparamos mediciones simultáneas de seeing obtenidas durante 14 noches con los monitores de movimiento diferencial de imagen (DIMM) usados en el Observatorio Astronómico Nacional en San Pedro Mártir (SPD) y en Cerro Tololo Inter-American Observatory (RoD). Para el conjunto de datos, compuesto de 1581 mediciones cuasi-simultáneas, encontramos que la media y la mediana de las diferencias de seeing RoD-SPD son +0.004±0.138" y +0.010", respectivamente. También descubrimos que la mediana de las diferencias de seeing RoD-SPD es +0.041" cuando el seeing es inferior a 1"; -0.032" cuando está entre 1", y 1.5" y -0.292" cuando es superior a 1.5". Dado que el seeing es usualmente menor que 1", concluimos que las mediciones hechas con unidades tipo SPD deben incrementarse entre 0.01" y 0.04" al ser comparadas con unidades tipo RoD. Esta corrección es mucho menor que la dispersión natural de medidas de seeing que ocurren a lo largo de cualquier noche, y tiene sentido hacerla sólo si las condiciones operativas en ambos sitios son prácticamente las mismas.

Micrurus spixii venom was studied after fractionation by Sephadex G-100 SF gel filtration chromatography. Several enzymatic activities and biological effects were investigated in whole venom and fractions. The venom was resolved in four peaks in a range of about 73.2-10.7 kDa molecular weight. Alkaline phosphatase and acetylcholinesterase activities were found in peak I, and procoagulant activity was seen in peak II. Phospholipase A2, hemorrhagic, and proteolytic activities were detected in peak III. A second procoagulant factor and proteinase were present in peak IV. Thrombin-like enzyme and direct hemolytic activities were not found in any assayed samples.