Conservation Genetics of the "Diablito" Poison Frog

Human activity is the main responsible for the biodiversity decline causing high rates of species extinction. The last few decades genetic factors have played important roles in determining population viability and extinction risk. Therefore, the discipline of conservation genetics emerged, taking advantage of molecular genetics tools to assess variation and study the fate of populations which are defined and identified by their genetic constituency. It is estimated that one-third of all amphibian species are threatened with extinction, and Neotropical species of frogs are no exception. The populations of the Diablito poison frog (Oophaga sylvatica) have abruptly declined in the last few decades. As a result, this species almost extinct in the Southern Ecuadorian part of its range. To develop conservation actions, one needs to identify conservation units, by choosing or prioritizing genetically distinct and reproductively independent populations for protection. In this study, I used microsatellite and mithocondrial DNA datasets, combined with high resolution pictures and bioclimatic data to asses of the existence of any genetic, morphological and/or ecological boundaries, and to reconstruct the recent demography of the populations. My study reveled two mitochondrial lineages with significant intraspecific divergence in aposematic coloration patterns. Moreover, based on both genetic and ecological exchangeability criteria, I propose that Diablito frogs in Ecuador are best characterized as two single evolutionariy significant units. However, a better sampling and further analysis should be considered to settle the appropriate (IUCN) conservation status and conservation units in this charismatic species

Modulation of ecdysal cyst and toxin dynamics of two Alexandrium (Dinophyceae) species under small-scale turbulence

Some dinoflagellate species have shown different physiological responses to certain turbulent conditions. Here we investigate how two levels of turbulent kinetic energy dissipation rates (epsilon = 0.4 and 27 cm(2) s(-3)) affect the PSP toxins and ecdysal cyst dynamics of two bloom forming species, Alexandrium minutum and A. catenella. The most striking responses were observed at the high epsilon generated by an orbital shaker. In the cultures of the two species shaken for more than 4 days, the cellular GTX(1+4) toxin contents were significantly lower than in the still control cultures. In A. minutum this trend was also observed in the C(1+2) toxin content. For the two species, inhibition of ecdysal cyst production occurred during the period of exposure of the cultures to stirring (4 or more days) at any time during their growth curve. Recovery of cyst abundances was always observed when turbulence stopped. When shaking persisted for more than 4 days, the net growth rate significantly decreased in A. minutum (from 0.25 +/- 0.01 day(-1) to 0.19 +/- 0.02 day(-1)) and the final cell numbers were lower (ca. 55.4%) than in the still control cultures. In A. catenella, the net growth rate was not markedly modified by turbulence although under long exposure to shaking, the cultures entered earlier in the stationary phase and the final cell numbers were significantly lower (ca. 23%) than in the control flasks. The described responses were not observed in the experiments performed at the low turbulence intensities with an orbital grid system, where the population development was favoured. In those conditions, cells appeared to escape from the zone of the influence of the grids and concentrated in calmer thin layers either at the top or at the bottom of the containers. This ecophysiological study provides new evidences about the sensitivity to high levels of small-scale turbulence by two life cycle related processes, toxin production and encystment, in dinoflagellates. This can contribute to the understanding of the dynamics of those organisms in nature

Relación angular radiológica de las superficies articulares de la tibia en sujetos asintomáticos

Se efectuó un estudio radiológico para determinar la relación angular existente entre las superficies articulares proximal y distal de 108 tibias correspondientes a 54 pacientes asintomáticos, de edades entre 14 y 72 años (media: 29,8). La medición se llevó a cabo con un «cobbometro» de Oxford en proyección anteroposterior y lateral. El ángulo medio entre ambas superficies fue de 3,3 ± 2,6° (intervalo de confianza al 95%: 2,8-3,8°) en proyección anteroposterior y de 5,5 ± 3,9° (intervalo de confianza: 4,7-6,3°) en proyección lateral. Cuando se consideró para cada paciente, la diferencia media de esta relación angular entre las tibias derechas e izquierdas fue inferior a 0,5° en ambas proyecciones.The angular relationship between proximal and distal articular surfaces was determined, through an Oxford Cobbometer, in 108 tibiae of 54 asymptomalic patients aging 14 to 72 years (mean: 30). Mean angle between both surfaces was 3.3 ± 2.6° (95% confidence interval: 2.8-3.8°) for the anteroposterior view and 5.5 ± 3.9° (95% confidence interval: 4.7-6.3°) for the lateral view. When considered individually for each patient, mean difference of this angular relationship among right and left tibiae was lesser than 0.5° for both projections

Modificaciones fisarias en el conejo inducidas por campos electromagnéticos

Se efectúa un estudio experimental para valorar los efectos de campos electromagnéticos de dos intensidades diferentes (2,4 y 10 Gauss) sobre la fisis de huesos largos. Se emplearon 45 conejos de 4 semanas divididos en tres grupos de 15 animales, a los que se colocó unas bobinas de Helmholtz en la rodilla derecha durante ocho horas diarias. Cinco animales de cada grupo fueron estimulados (subgrupo testigo). El primer grupo se sacrificó tras cuatro semanas, el segundo tras 12 semanas y el tercero llevó las bovinas durante 12 semanas y luego se sacrificó 12 semanas después para comprobar la duración de los efectos de la corriente. Los resultados demuestran que la diferencia en longitud entre los huesos estimulados y sus contralaterales fue mayor en el subgrupo sometido a 10 Gauss, aunque en ningún caso superior al 2,5%. La altura fisaria fue mayor en los huesos estimulados que en sus contralaterals, aunque no se apreciaron otras diferencias histológicas. No obstante, el cierre de la fisis se retrasó en todos los huesos estimulados con 10 Gauss y evolucionó normalmente en el resto. Los huesos de los subgrupos testigo no mostraron diferencias entre ellos.This study was carried out to compare the effects of two different electromagnetic fields (2,4 and 10 Gauss) on the growth plate of long bones. Forty five 4-week-old rabbits were divided in three groups of 15 animals each. All of them wore two Helmholtz coils on their right knee for 8 hours daily and then were sacrificed, the first after for 4 weeks, the second one after 12 weeks and the third one after 24 weeks. In this last group the coils were removed after 12 weeks and the animals allowed to live other 12 weeks to study the evolution of the growth plate after cesation of the stimulation. In each group, animals were not stimulated (sham subgroup). Results showed a greater difference in length in those bones stimulated with 10 Gauss, in respect to their contralateral, than the other subgroups. However these differences were less than 2,5% of the total length of the bone. Growth plate height of stimulated bones was greater than their contralateral in all subgroups with no other remarkable histological differences. Closure of the growth plate was delayed in the 10 Gauss stimulated bones but not in the rest. No differences were found among bones of sham subgroups at any time

Cauchy's residue theorem for a class of real valued functions

Let $[a,b]$ be an interval in $\mathbb{R}$ and let $F$ be a real valued function defined at the endpoints of $[a,b]$ and with a certain number of discontinuities within $[a,b]$. Having assumed $F$ to be differentiable on a set $[a,b] \backslash E$ to the derivative $f$, where $E$ is a subset of $[a,b]$ at whose points $F$ can take values $\pm \infty$ or not be defined at all, we adopt the convention that $F$ and $f$ are equal to 0 at all points of $E$ and show that $\mathcal{KH-}vt\int_{a}^{b}f=F(b) -F(a)$%, where $\mathcal{KH-}$ $vt$ denotes the total value of the \textit{% Kurzweil-Henstock} integral. The paper ends with a few examples that illustrate the theory.Comment: 6 page

A three decade mixed-method bibliometric investigation of the IEEE Transactions on Engineering Management

This paper offers a comprehensive overview of the IEEE Transactions on Engineering Management (IEEE TEM) from 1985 to 2017. This paper employs a mixed-method examination based on an in-depth interview with the new editor-in-chief regarding the challenges for the future of IEEE TEM, along with a bibliometric analysis of the journal. By using Web of Science Core Collection data, the analysis maps the knowledge produced and disseminated by IEEE TEM, revealing the most cited papers, the most frequently occurring keywords and the interconnection between them, the most prolific authors and their coauthorship network, and the most prolific countries for published articles. This paper also shows the main avenues of research covered by IEEE TEM and their evolution through the analysis of the correlation of keywords. This paper offers an example application of a mixed-method bibliometric analysis, seeking to extend the quantitative findings by including other sources of data

Estudio comparativo de dos métodos de radiografías forzadas para detectar la insuficiencia del ligamento cruzado anterior

En 32 pacientes con rotura unilateral de ligamento cruzado anterior (LCA) comprobada mediante artroscopia se efectuó previamente una radiografía forzada de ambas rodillas para estudiar el desplazamiento anterior de la tibia. Cada paciente fue estudiado mediante dos métodos diferentes, Lachman activo radiológico (LAR) y TelosR. Se asumió el diagnóstico radiológico de inestabilidad cuando la diferencia en el desplazamiento entre la rodilla lesionada y su control fue superior a 3 mm. Los resultados demuestran que la diferencia media del desplazamiento entre la rodilla lesionada y la normal fue superior a 3 mm con ambos métodos. En el lado interno 3,7 ± 3,7 mm con el LAR y 4,8 ± 5,8 mm con el Telos (diferencias no significativas). En el lado externo esta diferencia fue de 4,3 ± 4,7 nun con el LAR y de 6,8 ± 6 mm con el Telos (p < 0,05). A pesar de estos resultados, ambos métodos mostraron una sensibilidad para la detección de la insuficiencia ligamentosa inferior al 70%, lo que cuestiona su valor para el diagnóstico de la misma.In a prospective study, 32 patients with arthroscopically proved anterior cruciate ligament rupture were previously stressradiographied on both knees through two methods: the quadriceps-contraction technique (QCT) and the TelosR device. Instability was assumed when radiological differential displacement between injured and normal knee was greated than 3 mm. Results showed that this differential displacement was greater than 3 mm with both methods: 3,7 ± 3,7 mm v.s. 4,8 ± 5,8 mm in the medial side (differences not significant) and 4,3 ± 4,7 mm v.s. 6,8 ± 6 mm (p < 0.05) for the lateral side with the QCT and TelosR respectively. In spite of these differences, both methods showed a sensitivity lower than 70%

Microoptomechanical pumps assembled and driven by holographic optical vortex arrays

Beams of light with helical wavefronts can be focused into ring-like optical traps known as optical vortices. The orbital angular momentum carried by photons in helical modes can be transferred to trapped mesoscopic objects and thereby coupled to a surrounding fluid. We demonstrate that arrays of optical vortices created with the holographic optical tweezer technique can assemble colloidal spheres into dynamically reconfigurable microoptomechanical pumps assembled by optical gradient forces and actuated by photon orbital angular momentum.Comment: 4 pages, 3 figures, submitted to Optics Expres