646 research outputs found

    Estudio filogenético de los géneros de Trichopterygini de Sudamérica Austral (Lepidoptera: Geometridae): una nueva clasifi cación

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    Phylogenetic study of the genera of South American Austral Trichopterygini (Lepidoptera: Geometridae, Larentiinae): a new classifi cation. In this work, we evaluate the taxonomy of the Trichopterygini in Chile based on a phylogenetic analysis of the morphological attributes. In our analysis, we used Tatosoma and Sauris as outgroups. Two approaches were used to evaluate phylogenetic relationships: 1) parsimony criterion, and 2) Bayesian inference. Parsimony analysis was conducted in PAUP software, and Bayesian analysis with Markov chain Monte Carlo using the BayesPhylogenies software. Our results based on the phylogenetic hypothesis suggest a new taxonomic order for Trichopterygini of the Andean Region of Southern South America. The valid genera are: Arrayanaria Parra, Butleriana Parra, Danielaparra Kemal & Kocak, Fueguina Parra, Hoplosauris Butler, Lagynopteryx Berg, Llampidken Parra & Santos-Salas, Pachrophylla Blanchard, Parapachrophylla Parra, Rindgenaria Parra, Tomopteryx Philippi, Triptila Warren, Triptiloides Parra & Santos-Salas, Warrenaria Parra. The main changes with respect to the previous taxonomic order are: 1) the genus Lagynopteryx Berg is subordinated under the Trichopterygini; 2) Toxopaltes Warren is a junior synonym of Lagynopteryx; 3) Hoplosauris moesta is transferred to the genus Llampidken; 4) Llampidken valdiviana is a junior synonym of L. moesta; 5) Oparabia arenosa is newly combined with the genus Arrayanaria; 6) Danielaparra viridis is a junior synonym of D. fragmentata; 7) Lobophoraimbricaria is newly combined with the genus Danielaparra; 8) Triptiloides fasciata is a junior synonym of T. randallae; and 9) Parapachrophylla michelleae Parra n. sp. is described. Andean Region species are more closely related to the genus Tatosoma from New Zealand, the synapomorphies that demonstrate this are: swollen metaepimeron and hypertrophy of the second abdominal segment. A checklist of the genera and species of the tribe in the region, and the fi gures of adults and genitalia of some species are included.En este trabajo se evalúa la taxonomía de los Trichopterygini de Chile a partir de un análisis fi logenético de los atributos morfológicos. En nuestro análisis, hemos utilizado Tatosoma y Sauris como grupos externos. Se utilizaron dos enfoques para evaluar las relaciones fi logenéticas: 1) criterio de parsimonia, y 2) inferencia bayesiana. El análisis de parsimonia se realizó a través del programa PAUP y el análisis bayesiano con cadenas de Markov y Monte Carlo a través del programa BayesPhylogenies. Nuestros resultados basados en la hipótesis fi logenética sugieren un nuevo orden taxonómico para Trichopterygini de la Región Andina del Sur de Sudamérica. Los géneros válidos son: Arrayanaria Parra, Butleriana Parra, Danielaparra Kemal & Kocak, Fueguina Parra, Hoplosauris Butler, Lagynopteryx Berg, Llampidken Parra & Santos-Salas, Pachrophylla Blanchard, Parapachrophylla Parra, Rindgenaria Parra & Santos-Salas, Tomopteryx Philippi,Triptila Warren y Warrenaria Parra. Los principales cambios con respecto al orden taxonómico anterior son: 1) el género Lagynopteryx Berg se incorpora a Trichopterygini; 2) Toxopaltes Warren es el sinónimo junior de Lagynopteryx; 3) Hoplosauris moesta se incorpora al género Llampidken; 4) Llampidken valdiviana es el sinónimo junior de L. Moesta; 5) Oparabia arenosa es incorporada al género Arrayanaria; 6) Danielaparra viridis es el sinónimo junior de D. fragmentata; 7) Lobophora imbricaria es incorporada al género Danielaparra; Triptiloides fasciata es el sinónimo junior de T. randallae; y 9) Parapachrophylla michelleae Parra n. sp. es descrita. Las especies de la Región Andina están más cerca del Tatosoma de Nueva Zelanda, las sinapomorfi as que demuestran esto son: el metaepimeron hinchado y la hipertrofia del segundo segmento abdominal. Se incluye un catálogo de los géneros y especies de la tribu en la región, y fotografías de adultos y armaduras genitales de algunas especies

    NUEVOS REGISTROS DE DISTRIBUCION Y NOTAS BIOLOGICAS DE CYDIA LARGO HEPPNER (LEPIDOPTERA: TORTRICIDAE)

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    Improving Supports for Diverse Women Entering Executive Roles

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    We report on research identifying supports and barriers for women of diverse backgrounds entering executive roles in Canadian organizations. Intersectionality explains how different social categories such as gender, age and ethnoracial identity are interrelated and affect the professional lives of women. Family supports and networking are key to women\u27s success. The COVID-19 pandemic presents both problems and opportunities for working women. This research was conducted as a graduate student project in collaboration with the Women\u27s Executive Network. We offer recommendations for how organizations can better support women entering leadership roles

    Mortalidad bovina en la altillanura del Vichada

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    Recoge en forma resumida, los aspectos más relevantes encontrados por los autores, en una investigación realizada en la altillanura del Vichada, entre Santa Rosalia y Puerto Carreño, en hatos con ganadería bovina extensiva-extractiva, denominada: diagnóstico y alternativas de control al problema de la mortalidad bovina en un área del Vichada. Los predios estudiados se ubicaron a un máximo de 10 km del río Meta, se tomarón muestras de suelos como también de forraje de sabana nativa, adicionalmente muestras de sangre de la población bovina. Los resultados mostraron suelos con altos contenidos de Al intercambiable, Fe y Mn, fuertemente ácidos y con bajos contenidos de P, K y Ca. El contenido promedio foliar de N estuvo entre 0.74 y 0.94 por ciento equivalente a un valor de 4.68 y 5.88 por ciento de proteína cruda. El porcentaje de Ca, P y Mg fué de 0.19 y 0.15 por ciento en materia seca, los elementos que presentaron amplia variabilidad fueron B, Fe, K, Mn, P y Cu. Los valores medios de proteína cruda, fibra detergente netro de degradabilidad insitu de la materia seca fueron 5.28 , 62 y 46 por ciento. El decrecimiento paulatino de las concentraciones de minerales en forrajes se sabana, manejadas bajo quema, es notorio a medida que aumenta la edad del rebrote. Los valores de química sérica y hematología muestran alta variación en fósforo sérico, hierro, globulina, hemoglobina corpuscular media y glóbulos blancos lo que manifiesta una leucopenia posiblemente ocasionada por recirculación de poblaciones virales, hematozoos, subnutrición o agentes inmunodepresores. Esta investigación contribuye a entender la situación como de origen multicausal, donde la subnutrición continuada, es quizá la causa principal que predispone un mayor riesgo de enfermedad, lento desarrollo corporal, ineficiencia reproductiva y mortalidadGanadería bovin

    Single- and narrow-line photoluminescence in a boron nitride-supported MoSe2_2/graphene heterostructure

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    Heterostructures made from van der Waals materials provide a template to investigate proximity effects at atomically sharp heterointerfaces. In particular, near-field charge and energy transfer in heterostructures made from semiconducting transition metal dichalcogenides (TMD) have attracted interest to design model 2D "donor-acceptor" systems and new optoelectronic components. Here, using of Raman scattering and photoluminescence spectroscopies, we report a comprehensive characterization of a molybedenum diselenide (MoSe2_2) monolayer deposited onto hexagonal boron nitride (hBN) and capped by mono- and bilayer graphene. Along with the atomically flat hBN susbstrate, a single graphene epilayer is sufficient to passivate the MoSe2_2 layer and provides a homogenous environment without the need for an extra capping layer. As a result, we do not observe photo-induced doping in our heterostructure and the MoSe2_2 excitonic linewidth gets as narrow as 1.6~meV, hence approaching the homogeneous limit. The semi-metallic graphene layer neutralizes the 2D semiconductor and enables picosecond non-radiative energy transfer that quenches radiative recombination from long-lived states. Hence, emission from the neutral band edge exciton largely dominates the photoluminescence spectrum of the MoSe2_2/graphene heterostructure. Since this exciton has a picosecond radiative lifetime at low temperature, comparable with the energy transfer time, its low-temperature photoluminescence is only quenched by a factor of 3.3±13.3 \pm 1 and 4.4±14.4 \pm 1 in the presence of mono- and bilayer graphene, respectively. Finally, while our bare MoSe2_2 on hBN exhibits negligible valley polarization at low temperature and under near-resonant excitation, we show that interfacing MoSe2_2 with graphene yields a single-line emitter with degrees of valley polarization and coherence up to 15%\sim 15\,\%.Comment: version 3, 5 figure

    Reduction of Discrete Dynamical Systems with Applications to Dynamics Population Models

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    In this work we review the aggregation of variables method for discrete dynamical systems. These methods consist of describing the asymptotic behaviour of a complex system involving many coupled variables through the asymptotic behaviour of a reduced system formulated in terms of a few global variables. We consider population dynamics models including two processes acting at different time scales. Each process has associated a map describing its effect along its specific time unit. The discrete system encompassing both processes is expressed in the slow time scale composing the map associated to the slow one and the k-th iterate of the map associated to the fast one. In the linear case a result is stated showing the relationship between the corresponding asymptotic elements of both systems, initial and reduced. In the nonlinear case, the reduction result establishes the existence, stability and basins of attraction of steady states and periodic solutions of the original system with the help of the same elements of the corresponding reduced system. Several models looking over the main applications of the method to populations dynamics are collected to illustrate the general results
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