PAH Formation in O-rich Planetary Nebulae

Polycyclic aromatic hydrocarbons (PAHs) have been observed in O-rich planetary nebulae towards the Galactic Bulge. This combination of oxygen-rich and carbon-rich material, known as dual-dust or mixed chemistry, is not expected to be seen around such objects. We recently proposed that PAHs could be formed from the photodissociation of CO in dense tori. In this work, using VISIR/VLT, we spatially resolved the emission of the PAH bands and ionised emission from the [SIV] line, confirming the presence of dense central tori in all the observed O-rich objects. Furthermore, we show that for most of the objects, PAHs are located at the outer edge of these dense/compact tori, while the ionised material is mostly present in the inner parts of these tori, consistent with our hypothesis for the formation of PAHs in these systems. The presence of a dense torus has been strongly associated with the action of a central binary star and, as such, the rich chemistry seen in these regions may also be related to the formation of exoplanets in post-common-envelope binary systems.Comment: 14, accepted for publication in the MNRAS Journa

Plant hydraulic traits reveal islands as refugia from worsening drought.

Relatively mesic environments within arid regions may be important conservation targets as 'climate change refugia' for species persistence in the face of worsening drought conditions. Semi-arid southern California and the relatively mesic environments of California's Channel Islands provide a model system for examining drought responses of plants in potential climate change refugia. Most methods for detecting refugia are focused on 'exposure' of organisms to certain abiotic conditions, which fail to assess how local adaptation or acclimation of plant traits (i.e. 'sensitivity') contribute to or offset the benefits of reduced exposure. Here, we use a comparative plant hydraulics approach to characterize the vulnerability of plants to drought, providing a framework for identifying the locations and trait patterns that underlie functioning climate change refugia. Seasonal water relations, xylem hydraulic traits and remotely sensed vegetation indices of matched island and mainland field sites were used to compare the response of native plants from contrasting island and mainland sites to hotter droughts in the early 21st century. Island plants experienced more favorable water relations and resilience to recent drought. However, island plants displayed low plasticity/adaptation of hydraulic traits to local conditions, which indicates that relatively conserved traits of island plants underlie greater hydraulic safety and localized buffering from regional drought conditions. Our results provide an explanation for how California's Channel Islands function as a regional climate refugia during past and current climate change and demonstrate a physiology-based approach for detecting potential climate change refugia in other systems

Gas and dust from solar metallicity AGB stars

We study the asymptotic giant branch (AGB) evolution of stars with masses between $1~M_{\odot} - 8.5~M_{\odot}$. We focus on stars with a solar chemical composition, which allows us to interpret evolved stars in the Galaxy. We present a detailed comparison with models of the same chemistry, calculated with a different evolution code and based on a different set of physical assumptions. We find that stars of mass $\ge 3.5~M_{\odot}$ experience hot bottom burning at the base of the envelope. They have AGB lifetimes shorter than $\sim 3\times 10^5$ yr and eject into their surroundings gas contaminated by proton-capture nucleosynthesis, at an extent sensitive to the treatment of convection. Low mass stars with $1.5~M_{\odot} \le M \le 3~M_{\odot}$ become carbon stars. During the final phases the C/O ratio grows to $\sim 3$. We find a remarkable agreement between the two codes for the low-mass models and conclude that predictions for the physical and chemical properties of these stars, and the AGB lifetime, are not that sensitive to the modelling of the AGB phase. The dust produced is also dependent on the mass: low-mass stars produce mainly solid carbon and silicon carbide dust, whereas higher mass stars produce silicates and alumina dust. Possible future observations potentially able to add more robustness to the present results are also discussed.Comment: 27 pages, 24 figures; accepted for publication in MNRA

Disk evaporation in a planetary nebula

We study the Galactic bulge planetary nebula M 2-29 (for which a 3-year eclipse event of the central star has been attributed to a dust disk) using HST imaging and VLT spectroscopy, both long-slit and integral field. The central cavity of M 2-29 is filled with a decreasing, slow wind. An inner high density core is detected, with radius less than 250 AU, interpreted as a rotating gas/dust disk with a bipolar disk wind. The evaporating disk is argued to be the source of the slow wind. The central star is a source of a very fast wind (1000 km/s). An outer, partial ring is seen in the equatorial plane, expanding at 12 km/s. The azimuthal asymmetry is attributed to mass-loss modulation by an eccentric binary. M 2-29 presents a crucial point in disk evolution, where ionization causes the gas to be lost, leaving a low-mass dust disk behind.Comment: 11 pages, accepted for publication in "Astronomy and Astrophysics

Planeacion Financiera: Aplicación de las herramientas de la planeacion financiera en la Empresa Químicas Veterinarias S,A. en el periodo 2015-2016

Con esta investigación abordamos problemas de liquidez y rentabilidad que se estaban presentando en la empresa Químicas Veterinarias, S.A. con el objetivo de aplicar las principales herramientas de planeación financiera y explicar la importancia y utilidad de las mismas en toda empresa. Para llevar a cabo esta investigación, se utilizó la técnica de investigación documental y bibliográfica, además se revisó los principales Documentos de Gestión e información financiera de la empresa Químicas Veterinarias, S.A que se abordó en el caso práctico. Se logró así comprender en más detalle la problemática presentada por la Empresa. También se determinó las causas que generaron el problema y las posibles soluciones. Como solución, se implementaron las principales herramientas de planeación financiera como son: Presupuesto Maestro, Flujo de Caja Presupuestado y Estados Financieros Proforma, logrando así dar solución a los problemas de Liquidez con la Planeación del Efectivo y mejorar la Rentabilidad con la Planeación de las Utilidades a través del control y planificación de los gastos al analizar el efecto e importancia que los mismos presentaban en los Estados Financieros Proforma. Se puede concluir que las herramientas de planeación financiera son un instrumento de vital importancia en toda empresa si se quiere prolongar la existencia de la misma y si se quiere mantener un crecimiento y desarrollo sostenibles, puesto que con la planeación financiera adecuada se pueden alcanzar los objetivos estratégicos y mantener la “salud” financiera de empresa

Programa educativo escucha activa a directivos para la mejora de diálogo en el acompañamiento pedagógico en las instituciones de educación secundaria UGEL Maynas región Loreto 2022

This section briefly presents the most important findings in relation to the research carried out with the objective of evaluating the effect of the application of the active listening educational program in managers for the improvement of dialogue in pedagogical accompaniment in Educational Institutions. Secondary Education, Ugel Maynas, Loreto Region in 2022. The methodology used had the type of evaluative research with a field design, univariate, quasi-experimental, longitudinal, with a single group, using the pre-test and post-test to collect data through a performance test as an instrument validated by experts. The population and sample were 30 managers belonging to secondary level educational institutions. The results show that before applying the active listening educational program, the pedagogical accompaniment in managers was of medium level in 20.0% and low level in 80.0%. When applying the post test, the pedagogical accompaniment of managers was found at a high level in 6.7% and in a medium level at 93.3%. What evidences the effectiveness of the application of the educational program active listening in the directors in a significant way in the pedagogical accompaniment.En este acápite se presenta de manera breve los hallazgos más importantes en relación a la investigación llevada a cabo con el objetivo de evaluar el efecto de la aplicación del programa educativo denominado escucha activa en directivos para la mejora del diálogo en el acompañamiento pedagógico en las Instituciones de Educación Secundaria, Ugel Maynas, Región Loreto en el 2022. La metodología que se utilizó tuvo al tipo de investigación evaluativo con un diseño de campo, univariado, cuasi experimental, longitudinal, con grupo único, utilizando el pre test y post test para levantar datos mediante una prueba de desempeño como instrumento validado por expertos. La población y muestra fue de 30 directivos pertenecientes a instituciones educativas de secundaria. Los resultados muestran que antes de aplicar el programa educativo escucha activa el acompañamiento pedagógico en los directivos era de nivel medio en el 20,0% y de nivel bajo en el 80,0%. Al aplicar el post test se encontró al acompañamiento pedagógico de los directivos en nivel alto en el 6,7% y en nivel medio al 93,3%. Lo que evidencia la efectividad de la aplicación del programa educativo escucha activa en los directivos de modo significativo en el acompañamiento pedagógico.Esta seção apresenta brevemente os achados mais importantes em relação à pesquisa realizada com o objetivo de avaliar o efeito da aplicação do programa educacional denominado escuta ativa em gestores para a melhoria do diálogo no acompanhamento pedagógico em Instituições de Ensino Médio, Ugel Maynas, Região de Loreto em 2022. A metodologia utilizada foi do tipo pesquisa avaliativa com delineamento de campo, univariada, quase-experimental, longitudinal, com um único grupo, utilizando-se o pré e o pós-teste para coleta de dados por meio de teste de desempenho como instrumento validado por especialistas. A população e a amostra foram de 30 diretores pertencentes a instituições de ensino médio. Os resultados mostram que antes da aplicação do programa educativo escuta ativa, o acompanhamento pedagógico nos gestores era de nível médio em 20,0% e de nível baixo em 80,0%. Ao aplicar o pós-teste, o acompanhamento pedagógico dos gestores foi encontrado em nível alto em 6,7% e em nível médio em 93,3%. O que evidencia a efetividade da aplicação do programa educativo de escuta ativa nos gestores de forma significativa no acompanhamento pedagógico