Unraveling the complex phylogeographic history of freshwater fishes in Lower Central America: A study of the electric fish Brachyhypopomus occidentalis.

Lower Central America (LCA) has a complex biogeographic history shaped by the rise of the Isthmus of Panama and the global climatic oscillations of the Pleistocene. These events have been crucial in structuring biodiversity in LCA, but their consequences for the distribution and partitions of genetic diversity across the region remain to be elucidated. We combined complete mitochondrial genomes and nuclear ultraconserved elements (UCEs) to study the phylogeographic history and population genetic structure of the electric fish Brachyhypopomus occidentalis in LCA. Our results are consistent with the known phylogeographic history of B. occidentalis in LCA, but we update this history in several important ways that help illuminate the phylogeographic history of freshwater fishes in the region. We provide: i) support for three waves of colonization, two of which occurred prior to the final closure of the Panama Isthmus; ii) a more precise understanding of each colonization event, with evidence for a larger footprint of the first event, as well as genetic exchange across the continental divide in subsequent events; and iii) evidence for high levels of previously unrecognized population genetic structure across LCA. This updated model of colonization and diversification of B. occidentalis consists of three waves of dispersal and colonization, which triggered the evolution of geographic breaks in both nuclear and mitochondrial genomes across LCA. These processes are tightly linked to the dynamic uplift of the Isthmus, recent volcanic activity in the region, and the sea-level oscillations of the Pleistocene. These results improve previous phylogeographic inferences regarding the distribution and diversification of freshwater fishes in LCA, and generate testable hypotheses to guide future research exploring the factors shaping biodiversity in the region.

Effect of sonic versus ultrasonic activation on aqueous solution penetration in root canal dentin

The aim of this study was to observe the penetration of an aqueous solution into the root canal dentin under sonic activation and ultrasonic activation. Materials and Method: this study consisted of experimental in vitro research. In order to achieve a closed system, the apex of 45 single-rooted teeth was sealed with wax. The step-back technique was manually performed using a K50 apical master file and 3 groups were organized according to the protocol of the final irrigant activation: group I: non-activated chinese ink for 30 seconds, group II: chinese ink sonically activated with EndoActivator for 30 seconds, and group III: chinese ink ultrasonically activated with Varios 350 equipment for 30 seconds. Teeth were sectioned longitudinally, and the samples obtained were observed under a stereomicroscope at 1X magnification in order to be photographed and scanned to calculate the penetration area using the Image J software. The tinted radicular area was evaluated in relation to the total area of the root dentin. The tukey's post-hoc test and ANOVA were used for the statistical analysis (p<0.05). Results: group I and II obtained 9.13 percent and 9.42 percent penetration respectively, while in group III the highest degree of dye infiltration was achieved (13.9 percent), being statistically significant (p<0.001). Conclusions: ultrasonic activation produced a significantly higher penetration of the dye when compared to conventional activation and sonic activation.

Electrofóresis de las lipoproteínas séricas en habitantes andinos normales: Coporaque - Arequipa

El presente estudio realizado en 61 voluntarios sanos (27 hombres y 34 mujeres), que viven en zonas consideradas como grandes, en el pueblo de COPORAQUE ubicado en el valle del Colca a 3600 msnm. Se realizó el estudio con la finalidad de determinar un patrón electroforético de lipoproteinas sáricas, además de Lípidos y Colesterol total que está acorde con nuestra realidad. Se encontró que el promedio de la fracción alfa lipoproteina (HDL) es de 240.59 +/- 64.45 mg/dl, Pre beta Lipoproteina (VLDL) 143.13 +/- 35.12 mg/dl, fracción Beta Lipoproteina (LDL) 306.16 +/- 72.77 mg/dl, Lípidos totales 688.74 +/- 133.18 mg/dl además de Colesterol total 158.47 +/- 21.81 mg/dl. No habiendo diferencia significativa entre ambos sexos. Los diferentes factores interactuantes responsables de el presente patrón electroforético general de lipoproteinas además del Colesterol y Lípidos totales en este grupo de estudio, es discutido.