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UV-SCOPE is a mission concept to determine the causes of atmospheric mass loss in exoplanets, investigate the mechanisms driving aerosol formation in hot Jupiters, and study the influence of the stellar environment on atmospheric evolution and habitability. As part of these investigations, the mission will generate a broad-purpose legacy database of time-domain ultraviolet (UV) spectra for nearly 200 stars and planets. The observatory consists of a 60 cm, f/10 telescope paired to a long-slit spectrograph, yielding simultaneous, almost continuous coverage between 1203 {\AA} and 4000 {\AA}, with resolutions ranging from 6000 to 240. The efficient instrument provides throughputs > 4% (far-UV; FUV) and > 15% (near-UV; NUV), comparable to HST/COS and much better than HST/STIS, over the same spectral range. A key design feature is the LiF prism, which serves as a dispersive element and provides high throughput even after accounting for radiation degradation. The use of two delta-doped Electron-Multiplying CCD detectors with UV-optimized, single-layer anti-reflection coatings provides high quantum efficiency and low detector noise. From the Earth-Sun second Lagrangian point, UV-SCOPE will continuously observe planetary transits and stellar variability in the full FUV-to-NUV range, with negligible astrophysical background. All these features make UV-SCOPE the ideal instrument to study exoplanetary atmospheres and the impact of host stars on their planets. UV-SCOPE was proposed to NASA as a Medium Explorer (MidEx) mission for the 2021 Announcement of Opportunity. If approved, the observatory will be developed over a 5-year period. Its primary science mission takes 34 months to complete. The spacecraft carries enough fuel for 6 years of operations., Comment: 12 pages, 7 figures, 1 table. Conference presentation, 17 July 2022, SPIE Astronomical Telescopes and Instrumentation, Montreal, Canada

HZ 4 is a DA3.4C White Dwarf (WD) and a commonly used photometric standard star. While analyzing its suitability as a calibrator, data from TESS revealed an increase in flux by 43.2%, seen only on Sector 43 observed in 2021 September and October. The event duration is 28.8 hr, and the light curve shape is approximately symmetric and consists of a flux increase preceded and followed by a flux decrease of 11.4%. If periodic, the period would be >77 days. No other objects are observed in the Digital Sky Survey, Galaxy Evolution Explorer, or Wide-Field Infrared Explorer images within the TESS pixel in which HZ 4 resides. The event resembles the flux increases of long-lived WD pulsators, although HZ4 is not in the instability strip. There is no evidence of a binary companion, which suggests HZ4 is not a dwarf nova, nor photometric evidence of any circumstellar material.

The Star–Planet Activity Research CubeSat (SPARCS) is an upcoming NASA mission to understand the impact of low-mass stellar radiation on exoplanets. SPARCS will obtain photometric observations of low-mass stars in two bands: 153–171 nm (Far-UV; FUV) and 258–308 nm (Near-UV; NUV). SPARCS’ absolute calibration will be derived by observing White Dwarfs (WDs). WD selected as SPARCS calibrators should vary ≤7%. Here we present a study of UV variability of potential WD calibrators, based on Galaxy Evolution Explorer and HST/UVIS photometric observations. We collected data on a sample of 29 WDs from the Mikulski Archive for Space Telescopes and identified 8 potential SPARCS calibration targets in the NUV and 5 in the FUV, for a total of 10 distinct targets. Statistical analysis shows variability

Lyman-$\alpha$ transits have been detected from several nearby exoplanets and are one of our best insights into the atmospheric escape process. However, due to ISM absorption, we typically only observe the transit signature in the blue-wing, making them challenging to interpret. This challenge has been recently highlighted by non-detections from planets thought to be undergoing vigorous escape. Pioneering 3D simulations have shown that escaping hydrogen is shaped into a cometary tail receding from the planet. Motivated by this work, we develop a simple model to interpret Lyman-$\alpha$ transits. Using this framework, we show that the Lyman-$\alpha$ transit depth is primarily controlled by the properties of the stellar tidal field rather than details of the escape process. Instead, the transit duration provides a direct measurement of the velocity of the planetary outflow. This result arises because the underlying physics is the distance a neutral hydrogen atom can travel before it is photoionized in the outflow. Thus, higher irradiation levels, expected to drive more powerful outflows, produce weaker, shorter Lyman-$\alpha$ transits because the outflowing gas is ionized more quickly. Our framework suggests that the generation of energetic neutral atoms may dominate the transit signature early, but the acceleration of planetary material produces long tails. Thus, Lyman-$\alpha$ transits do not primarily probe the mass-loss rates. Instead, they inform us about the velocity at which the escape mechanism is ejecting material from the planet, providing a clean test of predictions from atmospheric escape models., Comment: Accepted for publication in MNRAS

Este documento estudió el impacto de la devaluación y la volatilidad de la tasa de cambio sobre la estructura a plazos de las tasas de interés en Colombia durante el periodo 2008 - 2020. Para este fin se utilizaron modelos de series de tiempo univariados y multivariados con umbrales. Entre los resultados se observó un efecto no lineal de la devaluación y la volatilidad de la tasa de cambio sobre el nivel y la pendiente de la curva. El empinamiento generado por un choque de devaluación se duplica en escenarios de alta devaluación y volatilidad, sin embargo para este último el impacto es de de mayor tamaño y duración. A diferencia de los modelos lineales, las desvalorizaciones generadas por un mayor nivel de endeudamiento resultaron ser significativas en escenarios de alta incertidumbre de la tasa de cambio. Además encontramos que los inversionistas valoran más niveles bajos de volatilidad que bajas devaluaciones del tipo de cambio ante un incremento en la aversión al riesgo global.

Introduction− Data Envelopment Analysis (DEA) is used to measure the relative performance of a series of distribution centers (DCs), using key indicators based on reverse logistics for a company that produces electric and electronic supplies in Colombia.Objective−The aim is to measure the relative perfor-mance of distribution centers based on Key Performance Indicators (KPI) from a supply network with reverse logistics.Methodology−A DEA model is applied through 5 steps: KPIs selection; Data collection for all 18 DCs in the net-work; Build and run the DEA model; Identify the DCs that will be the focus of improvement; Analyze the DCs that restrict or diminish the total performance of the system.Results− KPIs are defined, data is collected and KPI’s for each DCs are presented. The DEA model is run and the relative efficiencies for each DCs are determined. A frontier analysis is made and DCs that limit or reduce the performance of the system are analyzed to find options for improving the system.Conclusions−Reverse logistics, brings numerous ad-vantages for companies. The analysis of the indicators allows logistics managers involved to make relevant deci-sions for higher performance. The DEA model identifies which DCs have a relative superior and inferior perfor-mance, making it easier to make informed decisions to change, increase or decrease resources, and activities or apply best practices that optimize the performance of the network. Introducción− El análisis envolvente de datos (DEA), se usa para medir el desempeño relativo de una serie de centros de distribución (DCs), utilizando indicadores clave basados en logística inversa para una empresa que produce suministros eléctricos y electrónicos en Colombia.Objetivo− Medir el rendimiento relativo de los centros de distribución en función de indicadores clave (KPI) de una red de abastecimiento con logística inversa.Metodología− Se aplica un modelo DEA a través de 5 pasos: Selección de KPIs; Recopilación de datos para los 18 DCs en la red de distribución; Se construye y ejecuta el modelo DEA; Identificar los DCs que serán el foco de la mejora; Analizar los DCs que restringen o disminuyen el rendimiento total del sistema.Resultados− Inicialmente se definen KPI, a partir de los datos recolectados y se presentan los KPI para cada DCs. Se ejecuta el modelo DEA y se determinan las eficiencias relativas para cada DCs. Posteriormente, se realiza un análisis de la frontera y se analizan los DCs que limitan o reducen el rendimiento del sistema en busca de opciones para mejorar el sistema.Conclusiones− La logística inversa, trae numerosas ven-tajas para las empresas. El análisis de los indicadores permite a los gerentes de logística tomar decisiones rel-evantes para mejorar el desempeño del sistema. El mod-elo DEA identifica a los DCs que presentan rendimientos relativamente superiores e inferiores; lo cual facilita la toma de decisiones informadas para cambiar, aumentar o disminuir los recursos y las actividades, o aplicar las mejores prácticas que optimicen el rendimiento de la red.

La relacion entre la deuda publica y las tasas de interes de mercado ha sido un tema de amplia discusion en la literatura internacional, por sus implicaciones sobre los mercados financieros, las decisiones de ahorro e inversion de los agentes economicos y el agregado de la economia. En este articulo se analiza como y que tanto impacta la deuda del publica la pendiente o spread de la estructura a plazos de las tasas de interes en Colombia en el periodo 2003-2017. Para alcanzar su objetivo, primero se estima el spread a diferentes plazos, mediante un modelo de estado-espacio. Posteriormente, se determina el impacto de la deuda sobre aquel; utilizando modelos de series de tiempo univariados y multivariados. Por ultimo, se realiza una descomposicion historica de choques del spread. Los principales resultados obtenidos muestran que la deuda publica tiene un efecto positivo sobre el spread, tanto la emitida a tasa fija como a tasa variable. Asi mismo se encuentra que la emision de deuda a tasa variable tiene un mayor efecto sobre el spread de las tasas de interes de corto plazo, mientras la de tasa fija, mas sensible a las condiciones del mercado, tiene un mayor impacto sobre el spread de las tasas de interes de largo plazo. La implicacion de politica mas importante es el llamado a la reduccion del endeudamiento publico, con el objetivo de aminorar su impacto no deseado sobre el mercado financiero y la actividad economica.

Paul A. Scowen et al. -- 55 pags., 41 figs., 1 tab., We present the science cases and technological discussions that came from the workshop titled ¿Finding the ultraviolet (UV)-Visible Path Forward¿ held at NASA GSFC 2015 June 25-26. The material presented outlines the compelling science that can be enabled by a next generation space-based observatory dedicated for UV¿visible science, the technologies that are available to include in that observatory design, and the range of possible alternative launch approaches that could also enable some of the science. The recommendations to the Cosmic Origins Program Analysis Group from the workshop attendees on possible future development directions are outlined.

Given the increasing urban development and loss of forest areas which have an important ecological role in maintaining regional and continental bird populations there is a need to increase our knowledge about these population changes in order to understand their internal dynamics. From September 2011 to May 2012 birds occurring at the Universidad del Valle were monitored as part of the project “Use of the habitat by transcontinental migratory birds in Universidad del Valle’s Campus”. The information was obtained by observation transects, mist nets, and focal tracking of individuals. A total of 1995 records were obtained, represented in 12 orders, 29 families, and 76 species. The family with the highest number of species was Tyrannidae (14), followed by Thraupidae (eight) and Parulidae (eight). Fourteen species of Nearctic migratory birds were captured and banded. This information constitutes one of the few records of morphology obtained for resident and migratory birds in urban areas in Colombia. Dado el creciente desarrollo urbanístico y la pérdida de áreas arbóreas que desempeñan un papel ecológico importante en el mantenimiento de poblaciones de aves regionales y continentales, se hace necesaria la información continuada para conocer su dinámica interna. Entre septiembre 2011 y mayo 2012 se monitoreó la avifauna presente en la Universidad del Valle, como parte del proyecto “Uso de hábitat de las aves migratorias transcontinentales en el campus de la Universidad del Valle”. La información se obtuvo por medio del avistamiento de las especies a lo largo de recorridos de observación, captura con redes y seguimiento focal de individuos. Se obtuvo un total 1.995 registros, representados en 12 órdenes, 29 familias y 76 especies. La familia con mayor número de especies fue Tyrannidae (14) seguida de Thraupidae (ocho) y Parulidae (ocho). Se capturaron y anillaron 14 especies de aves migratorias neárticas. Esta información constituye uno de los pocos registros de morfología obtenida para las aves residentes y migratorias en zonas urbanas en Colombia.

(abridged) We present an analysis of high resolution optical spectra for a sample of very young, mid- to late M, low-mass stellar and substellar objects in Upper Sco and Taurus. Effective temperatures (T_eff) and surface gravities are derived from a multi-feature spectral analysis using TiO, NaI and KI, through comparison with the latest synthetic spectra. In combination, they allow us to determine T_eff to within 50K and gravity to within 0.25 dex. Our high-resolution analysis does not require extinction estimates. Moroever, it yields T_eff and gravities independent of theoretical evolutionary models. We find that our gravities for most of the sample agree remarkably well with the isochrone predictions for the likely cluster ages. However, discrepancies appear in our coolest targets: these appear to have significantly lower gravity (by up to 0.75 dex) than our hotter objects, even though our entire sample covers a relatively narrow range in T_eff (about 300K). This drop in gravity is also implied by inter-comparisons of the data alone, without recourse to synthetic spectra. We consider, and argue against, dust opacity, cool stellar spots or metallicity differences leading to the observed spectral effects; a real decline in gravity is strongly indicated. Such gravity variations are contrary to the predictions of the evolutionary tracks, causing improbably low ages to be inferred from the tracks for our coolest targets. We venture that these results may arise from evolutionary model uncertainties related to accretion, deuterium-burning and/or convection effects. Finally, when combined with photometry and distances, our technique for deriving gravities and temperatures provides a way of obtaining masses and radii for substellar objects independent of evolutionary models, as presented in Paper II., 74 pages, incl. 11 figures, accepted ApJ

Young stars surrounded by disks with very low mass accretion rates are likely in the final stages of inner disk evolution and therefore particularly interesting to study. We present ultraviolet (UV) observations of the ~5-9 Myr old stars RECX-1 and RECX-11, obtained with the Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph on the Hubble Space Telescope, as well as optical and near-infrared spectroscopic observations. The two stars have similar levels of near-UV emission, although spectroscopic evidence indicates that RECX-11 is accreting and RECX-1 is not. The line profiles of Hα and He I λ10830 in RECX-11 show both broad and narrow redshifted absorption components that vary with time, revealing the complexity of the accretion flows. We show that accretion indicators commonly used to measure mass accretion rates, e.g., U-band excess luminosity or the Ca II triplet line luminosity, are unreliable for low accretors, at least in the middle K spectral range. Using RECX-1 as a template for the intrinsic level of photospheric and chromospheric emission, we determine an upper limit of 3 × 10^(–10) M_☉ yr–1 for RECX-11. At this low accretion rate, recent photoevaporation models predict that an inner hole should have developed in the disk. However, the spectral energy distribution of RECX-11 shows fluxes comparable to the median of Taurus in the near-infrared, indicating that substantial dust remains. Fluorescent H2 emission lines formed in the innermost disk are observed in RECX-11, showing that gas is present in the inner disk, along with the dust.