Trophic ecology of the Endangered Darwin's frog inferred by stable isotopes

Indexación: Scopus.Acknowledgements. We thank Dr. Mauricio González-Chang for his contribution to invertebrate identification and Sally Wren for the revision of an earlier version of the manuscript. We are also extremely grateful to Tomás Elgueta Alvarez for providing Video S1. B.E.M.B. has a fellowship awarded by Universidad Andres Bello. This research project was approved by the Bioethics Committee at the Universi-dad Andres Bello, Chile (N°13/2015), and by permits N°5666/2013, N°230/2015, and N°212/2016 of the Chilean Agriculture and Livestock Service, and N°026/2013 and N°11/2015 IX of the Chilean National Forestry Corporation. This study was funded by the Dirección General de Investi-gación y Doctorados, Universidad Andres Bello, through grant N°DI-53-11/R and national funds through FONDE CYT N°11140902 and 1181758 (to C.S.A.).Darwin's frogs Rhinoderma spp. are the only known mouth-brooding frogs on Earth. The southern Darwin's frog, R. darwinii, is found in the temperate forests of southern South America, is listed as Endangered and could be the only extant representative of this genus. Based on stomach contents, invertebrate prey availability and stable isotope analysis, we determined for the first time trophic ecological parameters for this species. Our results showed that R. darwinii is a generalist sit-and-wait predator and a secondary consumer, with a trophic position of 2.9. Carbon and nitrogen isotope composition indicated that herbivore invertebrates are their main prey, detected in 68.1% of their assimilated food. The most consumed prey included mosquitoes, flies, crickets, grasshoppers and ants. Detritivore and carnivore invertebrates were also ingested, but in lower proportions. Our results contribute to a better understanding of the feeding habits of this fully terrestrial amphibian and provide the first insight into their role linking low forest trophic positions with intermediate predators. We provide valuable biological information for in situ and ex situ conservation which can be used when developing habitat protection, reintroduction and captive breeding programmes. As revealed here, stable isotope analysis is a valuable tool to study the trophic ecology of highly endangered and cryptic species. © The authors 2018.https://www.int-res.com/abstracts/esr/v36/p269-278

FLUCTUACIÓN POBLACIONAL DE Aeneolamia contigua (WALKER) EN EL CULTIVO DE CAÑA DE (Saccharum spp.) EN TABASCO, MÉXICO

Among the phytosanitary problems that limit the production of the sugar cane (Saccharum spp.) crop, the species Aeneolamia contigua (Walker) stands out, which causes yield reductions of up to 60 %; based on this, the population fluctuation of A. contigua nymphs and adults was identified for one year in the supply zone of the Presidente Benito Juárez Sugar Plant, in Tabasco, México. Weekly samples were taken from November 2007 to October 2008, in a one-hectare sugar plantation with the variety CP722086. Sampling of adults was carried out by using five yellow adhesive traps. The nymph sampling was carried out by counting the insects present in 10 sugar cane strains chosen randomly between the strains near the traps. The adult population presented three rises during the study period, in February, August and October, which were preceded respectively by a nymph population peak in January, July and September. The correlation analysis between population data of the plague, temperature and precipitation during the study period indicated that the latter influences population development significantly.Entre los problemas fitosanitarios que limitan la producción del cultivo de caña de azúcar (Saccharum spp.) destaca la especie Aeneolamia contigua (Walker) que ocasiona reducciones de rendimientos de hasta 60%, y con base en ello se identificó la fluctuación poblacional de ninfas y adultos de A. contigua durante un año en la zona de abastecimiento del Ingenio Presidente Benito Juárez, en Tabasco, México. Se realizaron muestreos semanales de noviembre de 2007 a octubre de 2008 en una plantación de caña de una hectárea con la variedad CP722086. El muestreo de adultos se realizó utilizando cinco trampas adhesivas de color amarillo. El muestreo de ninfas se realizó contando los insectos presentes en 10 cepas de caña elegidas al azar entre las cepas próximas a las trampas. La población de adultos presentó tres escaladas durante el período de estudio, en febrero, agosto y octubre, los cuales fueron precedidos respectivamente por un pico poblacional de ninfas en enero, julio y septiembre. El análisis de correlación entre datos poblacionales de la plaga, temperatura y precipitación durante el período de estudio, indicó que ésta última influye significativamente en su desarrollo poblacional

EFICIENCIA DE TRES DISEÑOS DE TRAMPA PARA LA CAPTURA DE Opsiphanes cassina fabricii (Boisduval) EN Elaeis guineensis Jacq, COMO ALTERNATIVA ORGÁNICA

The efficiency of three designs for traps used in the capture of Opsiphanes cassina fabricii adults, pest of the palm oil (Elaeis guineensis Jacq), was evaluated, and its population fluctuation during the study period was explored. The study was carried out in a 12 ha plantation in the municipalities of Cárdenas, Tabasco, México. The designs consisted in: (1) one plastic bag of 90X60 cm; (2) one 5 L container of barrel shape with 1 funnel, and (3) a rectangular box of 10 L with four funnels. In each trap, 0.5 kg of mature banana (Musa sp.) was used as bait. A complete random block design with three repetitions was used. The insects captured were collected each week, from June to August, 2008. 972 specimens of O. cassina were captured (546 males and 426 females), 69.2 % corresponded to the rectangular trap, 23.5 % to the barrel trap, and 7.2 % to the bag trap. A significant difference was found between treatments (Tukey, p?0.05). The population fluctuation presented a similar behavior with the three traps.Se evaluó la eficiencia de tres diseños de trampas para la captura de adultos de Opsiphanes cassina fabricii, plaga de la palma aceitera (Elaeis guineensis Jacq), y se conoció su fluctuación poblacional durante el periodo de estudio. La investigación se efectuó en una plantación de 12 ha ubicada en el municipio de Cárdenas, Tabasco, México. Los diseños consistieron en: (1) una bolsa plástica de 90X60 cm; (2) un recipiente de 5 L en forma de barril con 1 embudo, y (3) una caja rectangular de 10 L con cuatro embudos. En cada trampa se utilizó como cebo 0.5 kg de plátano maduro (Musa sp.). Se empleó un diseño de bloques completos al azar con tres repeticiones. Los insectos capturados se recolectaron cada semana, de junio-agosto, 2008. Se capturaron 972 especímenes de O. cassina (546 machos y 426 hembras), el69.2% correspondió a la trampa rectangular, el 23.5% a la trampa barril y 7.2% a la trampa bolsa. Se encontró diferencia significativa entre tratamientos (Tukey, p?0.05). La fluctuación poblacional presentó un comportamiento similar con las tres trampas

AVES RAPACES ASOCIADAS A LINDEROS ARBÓREOS ADYACENTES A CULTIVOS DE CAÑA DE AZÚCAR (Saccharum spp.) EN LA CHONTALPA, TABASCO

In order to identify the species of birds of prey that are associated to tree boundaries that demarcate sugar cane (Saccharum spp.) plantations, twenty-six visits were carried out from May 2013 to November 2014 to a stretch of 5 km of tree boundaries, in the afternoon, with the aim of detecting birds with binoculars, and to photograph them for their identification compared with field guides. Eleven species included in four families and three orders were identified: Accipitriformes (Cathartidae: Coragyps atratus and Cathartes aura; Accipitridae: Elanus leucurus, Buteogallus urubitinga, Buteo magnirostris and Buteo plagiatus), Strigiformes (Strigidae: Glaucidium brasilianum) and Falconiformes (Falconidae: Caracara cheriway, Herpetotheres cachinnans, Falco sparverius and Falco femoralis). All of them have potential as agents for biological control of pest rodents, but it is considered that E. leucurus is the species with greatest potential to consume rats and mice, is a resident and was found in 46 % of the visits; it was followed by B. magnirostris, which despite being a generalist in its diet, is a resident and was found in 96 % of the visits.Para identificar las especies de aves rapaces que se asocian a los linderos arbóreos que delimitan los cultivos de caña (Saccharum spp.), durante mayo, 2013 a noviembre 2014. Se efectuaron 26 recorridos en un tramo de 5 km de linderos arbóreos, por la tarde, con el fin de detectar aves rapaces, mediante un binocular, y ser fotografiadas para su identificación por comparación con guías de campo. Se identificaron 11 especies incluidas en cuatro familias y tres órdenes: Accipitriformes (Cathartidae: Coragyps atratus y Cathartes aura; Accipitridae: Elanus leucurus, Buteogallus urubitinga, Buteo magnirostris y Buteo plagiatus), Strigiformes (Strigidae: Glaucidium brasilianum) y Falconiformes (Falconidae: Caracara cheriway, Herpetotheres cachinnans, Falco sparverius y Falco femoralis). Todas tienen potencial como agentes de control biológico de roedores plaga, pero se considera que E. leucurus es la especie de mayor potencial al consumir ratas y ratones, es residente y se registró en 46% de los recorridos; seguida de B. magnirostris, que a pesar de ser generalista en su dieta, es residente y se registró en 96% de los recorrido

ESTRUCTURA POBLACIONAL DE ROEDORES PLAGA EN CAÑA DE AZÚCAR (Saccharum spp.) EN LA CHONTALPA, TABASCO, MÉXICO

study was carried out during 13 months regarding the population structure of Sigmodon toltecus and Oryzomys couesi, pest rodents in sugar cane (Saccharum spp.) cultivation in La Chontalpa, Tabasco, México, using snap traps in a sugar cane plantation and adjacent pasture used for cattle raising (18° 05’ 25’’ N, 93° 40’ 43’’ W). The study was developed for a year (2013-2014) beginning in September. Information was obtained about the number of males with scrotum testes, males with abdominal testes, reproductive and non-reproductive females, and number of embryos. The results were variable, but in general it was observed that the captures of individuals and records of S. toltecus embryos was higher than those of O. couesi, both in the sugar cane crop and in the adjoining pasture; likewise, there was a tendency to capture and record a higher number of individuals and embryos of both species of rodents during the period of September 2013 to March 2014, coinciding with an advance age of the sugar cane crop.Se realizó un estudio de 13 meses sobre la estructura poblacional de Sigmodon toltecus y Oryzomys couesi, roedores plaga del cultivo de caña de azúcar (Saccharum spp.) en La Chontalpa, Tabasco, México, utilizando trampas de golpeo en un cultivo de caña y en un pastizal adyacente para la cría de ganado vacuno (18° 05’ 25’’ N, 93° 40’ 43’’ W). El estudio fue desarrollado durante un año (2013-2014) iniciando en septiembre. Se obtuvo información sobre el número de machos con testículos escrotados, machos con testículos abdominales, hembras reproductivas, no reproductivas y cantidad de embriones. Los resultados fueron variables, pero se observó que en general las capturas de individuos y registros de embriones de S. toltecus fue mayor que las de O. couesi, tanto en el cultivo de caña como en el pastizal contiguo; asimismo, hubo tendencia a capturar y registrar mayor cantidad de individuos y embriones de ambas especies de roedores en el período de septiembre de 2013 a marzo de 2014, coincidiendo con una edad avanzada del cultivo de caña de azúcar

Effect of Microwave and Ultrasound-Assisted Extraction on the Phytochemical and In Vitro Biological Properties ofWillow (Salix alba) Bark Aqueous and Ethanolic Extracts

White willow (Salix alba) is a medicinal plant used in folk medicine. In this study, aqueous and ethanolic willow bark extracts were obtained via ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE), and analyzed regarding their phytochemical (total phenolics, phenolic acids, flavonoids, and tannins) content and in vitro biological properties (antibacterial and antifungal activity, acetylcholinesterase AChE inhibitory activity and anti-inflammatory effects). The highest phenolic, tannin, and flavonoid contents were found for willow bark extracts obtained via microwave-assisted extraction using ethanol as a solvent (SA-ME). The polyphenol load of all MAE and UAE extracts was higher when conventional solid–liquid extraction was applied (r < 0.05). The antioxidant capacities were stronger for microwave-assisted ethanolic extracts, with the lowest IC50 values of 12 g/mL for DPPH and a value of 16 g/mL for ABTS +, whereas the conventional extraction had the highest IC50 values (22 g/mL and 28 g/mL, respectively). Willow bark extract showed antibacterial activity against Gram-positive bacteria S. aureus and P. aeruginosa. AChE inhibitory activity was dependent on the extraction method and solvent used, and the highest inhibition among samples was observed for SA-ME. Taken altogether, our findings suggest that willow (Salix alba) bark extract obtained via ethanolic microwave-assisted extraction is a phytochemical-rich resource with in vitro, anti-inflammatory, and AchE inhibitory properties and, therefore, potential multiple medicinal end-uses.NCSU faculty start-up funds (M.M. 411050-02834)Junta de Extremadura (ref. GR21121—AGA008)European Regional Development Fund (FEDER)University National of Agriculture (Honduras) (Ref. C-DSIP-008-2023-UNAG

Unraveling beam self-healing

We show that, contrary to popular belief, non only diffraction-free beams may reconstruct themselves after hitting an opaque obstacle but also, for example, Gaussian beams. We unravel the mathematics and the physics underlying the self-reconstruction mechanism and we provide for a novel definition for the minimum reconstruction distance beyond geometric optics, which is in principle applicable to any optical beam that admits an angular spectrum representation. Moreover, we propose to quantify the self-reconstruction ability of a beam via a newly established degree of self-healing. This is defined via a comparison between the amplitudes, as opposite to intensities, of the original beam and the obstructed one. Such comparison is experimentally accomplished by tailoring an innovative experimental technique based upon Shack-Hartmann wave front reconstruction. We believe that these results can open new avenues in this field

Influence of Nutrients and pH on the Efficiency of Vertical Flow Constructed Wetlands Treating Winery Wastewater

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Winery wastewater is characterized by high organic content, low nutrient content and low pH at least during vintage periods. The effect of nutrient shortage and low pH on constructed wetlands (CWs) operation was scarcely studied, but early field studies indicate that some operational problems can arise. This work aims to determine the effect of nutrient shortage and acidic pH during the treatment of high organic load wastewater in one-step vertical subsurface flow (VF) CWs. Two lab scale VF units at hydraulic loading rates over 70 L/m2·d and surface loading rate in the range of 110−170 g COD/m2·d were operated for periods with and without nutrients in the influent as well as with influent pH of 7.0 and 4.5. The results showed that neither low nutrient nor low pH impair organic matter removal whilst low pH decreased nitrogen removal rates. At low pH, the effluent concentration of ammonia and nitrate increased, indicating deterioration in both nitrification and denitrification processes. The paper discuss the implications of these findings for a better strategy in the treatment of winery process wastewater, such as options for separate treatment or its combination with other nutrient-containing streams

Modeling and control with friction compensation of a pendubot system

[EN] The pendubot is a two degree of freedom mechanical underactuated system that is used as an educational and research platform in the areas of robotics and control. It is considered as an  underactuated system because it has only one control input. Although several control laws have been applied to stabilize the pendubot, most of them neglect the effects of friction. In this article, the analysis is different, since it is considered a pendubot system in which the actuated joint has a significant amount of friction that cannot be neglected. First, we review some of the existing friction models in the literature, including one that was recently proposed by the authors. Then we describe the implementation of some stabilization controllers that compensate for the effects of friction. Finally, an exhaustive comparison of the presented friction compensators is made to improve the performance of a real pendubot system.[ES] El pendubot es un sistema mecánico subactuado de dos grados de libertad que comúnmente se utiliza como plataforma educacional y de investigación en las áreas de robótica y control. Se le considera como un sistema subactuado debido a que sólo cuenta con una entrada de control. Aunque se han aplicado distintas leyes de control para estabilizar el pendubot, la mayoría de ellas desprecian los efectos de fricción. En este artículo el análisis es diferente, ya que se considera un sistema pendubot en el que la articulación actuada tiene una cantidad de fricción significativa, que no se puede despreciar. En primer lugar, se revisan algunos modelos de fricción existentes en la literatura, incluyendo uno que fue propuesto por los autores recientemente. Después, se describe la implementación de algunos controladores de estabilización que compensan los efectos de la fricción. Por ultimo, se hace una comparación exhaustiva de los compensadores de fricción presentados para mejorar el desempeno de un sistema pendubot real.Este trabajo fue apoyado parcialmente por el Tecnológico Nacional de México y la Universidad Autónoma de Ciudad Juárez.Soto, I.; Campa, R.; Sánchez-Mazuca, S. (2020). Modelado y control con compensación de fricción de un sistema pendubot. Revista Iberoamericana de Automática e Informática industrial. 18(1):39-47. https://doi.org/10.4995/riai.2020.13083OJS3947181Armstrong-Helouvry, B., 1991. Control of Machines with Friction. Kluwer Academic Publishers. https://doi.org/10.1007/978-1-4615-3972-8Canudas de Wit, C., Olson, H., Astrom, K., Lischinsky, P., 1995. A new model for control of system with friction. IEEE Transactions on Automatic Control 40, 419-425. https://doi.org/10.1109/9.376053Courtney-Pratt, J., Eisner, E., 1957. The effect of a tangential force on the contact of metallic bodies. Proceedings of the Royal Society A 238, 529-550. https://doi.org/10.1098/rspa.1957.0016Dahl, P., 1968. A solid friction model. Technical report TOR-0158(3107-18)-1, The Aerospace Corporation. https://doi.org/10.21236/ADA041920Fantoni, I., Lozano, R., Spong, M. W., 2000. Energy based control of the pendubot. IEEE Transactions on Automatic Control 45, 79-86. https://doi.org/10.1109/9.847110Guemghar, K., 2005. On the use of input-output feedback linearization techniques for the control of nonminimum-phase systems. Ph.D. thesis, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.Johannes, V. I., Green, M. A., Brockley, C. A., 1973. The role of the rate of application of the tangential force in determining the static friction coefficient. Wear 24, 381-385. https://doi.org/10.1016/0043-1648(73)90166-XMa, X. Q., Su, C. Y., 2002. A new fuzzy approach for swing up control of pendubot. In: Proceedings of the American Control Conference. Anchorage, AK, USA.Morin, A., 1833. New friction experiments carried out at Metz in 1831-1833. Proceedings of the French Royal Academy of Sciences 4, 1-128.O'Flaherty, R. W., Sanfelice, R. G., Teel, A. R., 2008. Hybrid control strategy for robust global swing-up of the pendubot. In: Proceedings of the American Control Conference. Seattle, WA, USA. https://doi.org/10.1109/ACC.2008.4586692Rabinowics, E., 1956. Stick and slip. Scientific American 194, 109-118. https://doi.org/10.1038/scientificamerican0256-109Sanchez-Mazuca, S., Campa, R., 2013. An improvement proposal to the static friction model. Mathematical Problems in Engineering 2013. https://doi.org/10.1155/2013/946526Sanchez-Mazuca, S., Soto, I., Campa, R., 2015. Modeling and control of a pendubot with static friction. In: Cecarelli, M., Hernandez Martínez, E. E. (Eds.), Multibody Mechatronic Systems: Proceedings of the MUSME Conference held in Huatulco, Mexico, October 21-24, 2014. Springer, pp. 229- 240. https://doi.org/10.1007/978-3-319-09858-6_22Spong, M. W., Block, D. J., 1995. The pendubot: a mechatronic system for control research and education. In: Proceedings of the IEEE Conference on Decision and Control. New Orleans, LA, USA.Stribeck, R., 1902. The key qualities of sliding and rolling bearings. (in German) Zeitschrift Des Vereins Deutscher Ingenieure 46, 1342-1348.Wang, W., Yi, J., Zhao, D., Liu, X., 2004. Adaptive sliding mode controller for an underactuated manipulator. In: Proceedings of the International Conference on Machine Learning and Cybernetics. Shangai, China.Xin, X., Kaneda, M., Oki, T., 2002. The swing-up control for the pendubot based on energy control approach. In: Proceeding of the IFAC World Congress. Barcelona, Spain. https://doi.org/10.3182/20020721-6-ES-1901.00889Zhang, M. J., Tarn, T. J., 2002. Hybrid control of the pendubot. IEEE Transactions on Mechatronics 7, 79-86. https://doi.org/10.1109/3516.99089

Assessing the Polarization of a Quantum Field from Stokes Fluctuation

We propose an operational degree of polarization in terms of the variance of the projected Stokes vector minimized over all the directions of the Poincar\'e sphere. We examine the properties of this degree and show that some problems associated with the standard definition are avoided. The new degree of polarization is experimentally determined using two examples: a bright squeezed state and a quadrature squeezed vacuum.Comment: 4 pages, 2 figures. Comments welcome