Feeding ecology of elasmobranch fishes in coastal waters of the Colombian Eastern Tropical Pacific

<p>Abstract</p> <p>Background</p> <p>Stomach contents of 131 specimens of five elasmobranch species (<it>Mustelus lunulatus</it>, <it>Dasyatis longa</it>, <it>Rhinobatos leucorhynchus</it>, <it>Raja velezi </it>and <it>Zapteryx xyster</it>) caught in the central fishing zone in the Pacific Ocean of Colombia were counted and weighed to describe feeding habits and dietary overlaps.</p> <p>Results</p> <p>Twenty-one prey items belonging to four major groups (stomatopods, decapods, mollusks and fish) were identified. Decapod crustaceans were the most abundant prey found in stomachs. The mantis shrimp <it>Squilla panamensis </it>was the main prey item in the diet of <it>M. lunulatus</it>; tiger shrimp <it>Trachypenaeus </it>sp. was the main prey item in the diet of <it>Rhinobatos leucorhynchus </it>and <it>Raja velezi</it>, and Penaeidae shrimp were the main prey items in the diet of <it>Z. xyster</it>. Furthermore, fish were important in the diet of <it>Raja velezi, Z. xyster </it>and <it>D. longa</it>. The greatest diet breadth corresponded to <it>Z. xyster </it>whereas <it>M. lunulatus </it>was the most specialized predator. Finally, four significant diet overlaps between the five species were found, attributable mainly to Squillidae, Penaeidae and Fish.</p> <p>Conclusion</p> <p>Shrimps (Penaeidae and stomatopods) and benthic fishes were the most important food types in the diet of the elasmobranch species studied. Diet breadth and overlap were relatively low. Determination of food resource partitioning among the batoid species studied was not possible. However, we identified partitions in other niche axes (time of feeding activity and habitat utilization). It is possible to assume that diffuse competition could be exceeding the biunivocal competition among the studied species. Therefore, this assemblage would have a strong tendency to trophic guild formation.</p

Was the GLE on May 17, 2012 linked with the M5.1-class flare the first in the 24th solar cycle?

On May 17, 2012 an M5.1-class flare exploded from the sun. An O-type coronal mass ejection (CME) was also associated with this flare. There was an instant increase in proton flux with peak at $\geq 100$ MeV, leading to S2 solar radiation storm level. In about 20 minutes after the X-ray emission, the solar particles reached the Earth.It was the source of the first (since December 2006) ground level enhancement (GLE) of the current solar cycle 24. The GLE was detected by neutron monitors (NM) and other ground based detectors. Here we present an observation by the Tupi muon telescopes (Niteroi, Brazil, $22^{0}.9 S$, $43^{0}.2 W$, 3 m above sea level) of the enhancement of muons at ground level associated with this M5.1-class solar flare. The Tupi telescopes registered a muon excess over background $\sim 20\%$ in the 5-min binning time profile. The Tupi signal is studied in correlation with data obtained by space-borne detectors (GOES, ACE), ground based neutron monitors (Oulu) and air shower detectors (the IceTop surface component of the IceCube neutrino observatory). We also report the observation of the muon signal possibly associated with the CME/sheath striking the Earth magnetosphere on May 20, 2012. We show that the observed temporal correlation of the muon excess observed by the Tupi muon telescopes with solar transient events suggests a real physical connection between them. Our observation indicates that combination of two factors, the low energy threshold of the Tupi muon telescopes and the location of the Tupi experiment in the South Atlantic Anomaly region, can be favorable in the study and detection of the solar transient events. Our experiment provides new data complementary to other techniques (space and ground based) in the study of solar physics.Comment: 9 pages, 10 figure

First report of the eriophyoid mite abacarus doctus (Prostigmata: Eriophyidae) infesting sugarcane in El Salvador.

Este es el primer reporte de Abacarus doctus Navia & Flechtmann en El Salvador y el segundo en el mundo.Variabilidad morfológica entre poblaciones salvadoreñas y el material tipo son apuntadas y estudios detallados que permitan una mejor compreensión de su significado en la sistemática de los Eriophyoidea son sugeridos. Observaciones de campo acerca las infestaciones de A. doctus en El Salvador son presentadas así como la necesidad de evaluaciones adicionales sobre el status de la plaga en El Salvador y su posible presencia en otros países productores de caña de azúcar en América Central.Scientific Notes

Evaluación de técnicas de tinción para la observación de bandas de crecimiento en vértebras de elasmobranquios tropicales

The aim of this study was to assess the suitability of different vertebrae staining techniques for the visualization and counting of growth bands in tropical species of batoids (Narcine leoparda, Urotrygon aspidura, Hypanus longus, Potamotrygon magdalenae) and sharks (Alopias pelagicus, Carcharhinus falciformis, Sphyrna lewini, Sphyrna corona and Mustelus lunulatus). Different cutting thicknesses and staining protocols were tested, analysing the precision and bias of each combination to identify the most accurate technique for estimating age. Vertebral sections of 0.4 mm were more suitable for batoids, except for Narcine leoparda; for this species and for all the shark species assessed, sections of 0.5 mm are recommended. Different combinations of stain and exposure time were required to achieve the best visualizations of vertebral growth band pair for the shark and ray species. Intraspecific variation occurred among vertebrae size of batoids. Our results confirm the importance of defining a suitable species-specific protocol for sectioning and staining hard structures before carrying out an age and growth study to improve the reliability of the age estimates.El objetivo de este estudio fue evaluar la efectividad de diferentes técnicas de tinción de vértebras en la visualización y el conteo de bandas de crecimiento en especies tropicales de batoideos (Narcine leoparda, Urotrygon aspidura, Hypanus longus, Potamotrygon magdalenae) y tiburones (Alopias pelagicus, Carcharhinus falciformis, Sphyrna lewini, Sphyrna corona y Mustelus lunulatus). Se probaron diferentes espesores de corte y protocolos de tinción, analizando la precisión y el sesgo de cada combinación para identificar la técnica más precisa para estimar la edad. Las secciones vertebrales de 0,4 mm fueron más adecuadas para batoideos, excepto para Narcine leoparda; para esta especie y para todas las especies de tiburones evaluadas, se recomiendan secciones de 0,5 mm. Se identificaron diferentes combinaciones de tinción y tiempo de exposición para lograr las mejores visualizaciones de las bandas de crecimiento vertebral en las especies de tiburones y rayas. En los batoideos se identificó variación intraespecífica de acuerdo con el tamaño de las vértebras. Nuestros resultados confirman la importancia de definir un protocolo especie-específico adecuado para cortar y teñir las estructuras duras antes de realizar un estudio de edad y crecimiento y así incrementar la confiabilidad de las estimaciones de edad

Evaluation of physical and chemical soil properties under different management types in the south-western Colombian Andes

Aim of study: Evaluating the variability of physical and chemical soil properties under different soil uses in an experimental farmland of the southwestern Colombian Andes.Area of study: This research was conducted at the Botana Experimental Farm in the mountainous area of Nariño, at the south-western Colombia.Material and methods: nine soil variables were measured under six soil uses which included traditional agriculture, agroforestry systems, and a 67-year-old secondary forest that was used as a reference for comparisons with other soil uses. Data was analyzed through Principal Component Analysis and Duncan’s tests.Main results: organic carbon, cation exchange capacity, clay contents and base saturation were the variables with higher variability among soil uses. The secondary forest and an agroforestry system with alley-cropped wax laurel showed the best soil conditions, whilst pastures and monoculture potato crop plots showed the least desirable conditions for all variables.Research highlights: We found that soils under alley-crop with wax laurel presented the characteristics most similar to the secondary forest. Conversely, soils under alley-crop with alder resembled the soils under intensive management (pasture and potato monocrop); which is related to the inadequate management of this agroforestry systems, provoking that the woody component does not accomplish its goal when implemented.Keywords: soil; agroforestry systems; Andes; forest.Abbreviations used: ACAL, Alley cropping of Alder Trees, ACWL; Alley cropping of Wax Laurel; AFS, agroforestry systems; AWC, available water capacity; BD, Bulk Density; BS, Base saturation; CEC, Cation Exchange Capacity; CLA, Clay; CI, Confidence Intervals, INF, Infiltration; ANOVA, Analysis of Variance; OC, Soil Organic Carbon;  PAST, Pasture; PCA, Principal Component Analysis; PC, Principal Component; POCR, Potato Crop; POR, Soil Porosity; SCAL, Scattered Alder Trees; SEFO, Secondary Forest; SU, soil uses; AU, Animal unit

Butter oil (ghee) enrichment with aromatic plants: Chemical characterization and effects on fibroblast migration in an in-vitro wound healing model

Ghee is a dairy product widely consumed in India, north-Africa, and Middle East countries, having beneficial pharmacological effects. This study aims to characterize the effects of aromatic plants addition (rosemary and clove) on the nutritional, volatile and oxidative profile of cow ghee and to evaluate the effect of flavored ghee on the fibroblasts migration during wound healing in vitro assay. Two flavored ghee products were obtained by adding clove (CG) and rosemary (RG) as aromatic plants through maceration in cattle traditional ghee (BT). It was revealed that enriched ghee samples had significantly lower peroxide values (6.76 and 6.80 meqO2 /kg) compared to control samples (8.20 meqO2 /kg). Moreover, the addition of rosemary and clove change the volatile profile, and increased the retinol levels of ghee (BT: 1.3 mg/kg; CG: 1.9 mg/kg; and RG: 3.05 mg/kg). Liquid-chromatography analyses revealed the presence of targeted phenolic compounds such as carnosic acid, rutin and gallic acid in CG and RG, showing thus, the transfer of polyphenols from aromatic plants into the ghee matrix. On the other hand, the fatty acid composition of ghee remained unchanged. The major components of the prepared ghee samples contributed to rising significantly the human fibroblast migration in wound healing in vitro assay. The results obtained underline that the flavored ghee samples could improve skin regeneration, making them potentials therapeutic ingredients in skincare formulations