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The exosphere is the uppermost layer of the terrestrial atmosphere, mainly composed of atomic hydrogen (H) that resonantly scatters solar far-ultraviolet (FUV) photons at 121.56 nm, also referred to as Lyman-Alpha (Ly-α) emission. Analysis of this emission has been used to determine the global, three-dimensional, and time-dependent exospheric H density structure, which is essential to assess the permanent escape of H to space as well as to determine their role in governing the transient response of terrestrial plasma environment to space weather. Thus, Ly-α emission and its by-product, the H density, are highly desirable to the magnetospheric community. On the other hand, this emission can also be regarded as a significant source of contamination during studies of FUV targets such as O/B-type stars, planetary and exoplanetary atmospheres, and the circumgalactic medium, especially when observations are acquired from Earth-orbiting instruments. In this case, accurate specification of exospheric Ly-α photon flux and its subsequent removal is required by the planetary and astrophysics community studying solar/extra-solar system objects. This work introduces EXOSpy, an open-source python-based package that provides several models of terrestrial exospheric H density and calculates exospheric Ly-α emission with a high potential to contribute to investigations in both communities. We present several examples to demonstrate how EXOSpy can be used to (i) validate current and new exospheric models based on actual Ly-α radiance data, (ii) estimate exospheric contamination for a given instrument’s line-of-sight and spatial location, and (iii) provide support for new space-based FUV instrument design.

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.

Oil price downturn has directly affected employability in our industry at a global scale since 2014, dropping the workforce to significantly low levels. In Colombia, many young professionals finished the undergrad with the intention of building a competitive industry and leverage the national economy through their knowledge; however, most of them have not even had the chance to get a first job as they are in a market that values the experience they do not have. Having said this, it makes evident the need of differentiation from candidates in selection processes and considering other alternatives for their life projects. As a social responsibility act, the SPE Colombian Section – in conjunction with volunteers working on technical and human resources areas - created a solid strategy based on real needs concluded from data collected at SPE Colombian Section events to boost up young professionals development path and provide guidance for decision making on their careers. "ENJOG" Encuentro de Jovenes de la Industria de Oil and Gas proved that to join efforts is the best way to break barriers and to solve problems. The results have shown a significant impact on those involved in the program created and the knowledge worth reproducing is documented in this paper. More than 500 young professionals have been participating in the strategy.

In Colombia, one of the biggest challenges for the oil and gas industry is to generate a sound reputation and a new perception about its benefits to the communities located in the area of influence. Even though, the oil and gas industry generates between 9 to 11% of the Gross Domestic Product (GDP) in Colombia, there is a negative perception of local communities due to the impacts of the operations of the industry on the people and environment; as a consequence, the implementation of pedagogical methodologies to educate communities about the sustainable view of the modern Oil and gas Industry, and the importance to the access to energy and water is a need. In this sense, programs such as Energy4Me and PetrolCopa Reto Escolar have been implemented over the last two years in different regions of Colombia, which have allowed the collection of a considerable amount of data with great technical and social value from more than 10000 participants. This information has been refined, processed and analyzed to show how data science generates added value in the continuous improvement of the methodologies implemented by the data center of SPE Colombian Section; thus, improving relationship between industry and local communities through a fluent communication and knowledge channel. The analysis of the information and its implementation in these educational programs was carried out through the application of different statistical methods and digital tools for processing and monitoring information, which resulted in the design of optimal processes for the collection of structured and unstructured data such as; community behavior parameters, social problems, demographic characteristics and acquired technical knowledge. This process took into account at the same time other related variables such as the heterogeneity of rural communities, logistical and operational challenges and the social conditions of each region. The data gathering process involved 500 volunteers in more than 5000 people from different regions, ethnic groups, ages, gender and level of education. Once the information was correlated and the methodological approach of the programs improved, trends and direct relationships were established between the data analyzed and the decrease in the rate of rejection by the communities towards Oil and Gas industry in the study regions.

Con la intención de seguir creando espacios para que se exprese la voz de nuestra comunidad, este concurso de ensayo, del cual presentamos hoy resultados en un libro que conjuga expresiones artísticas rigurosas y provocadoras, es un homenaje a las más de tres décadas de formación en una institución en la que el escucharnos, leernos, discutirnos y apoyarnos, junto con la confianza, la perseverancia y la inequívoca exaltación de la dignidad humana, son los motivos para continuar pensando, acaso, pensando-nos. Las diferentes expresiones artísticas que componen este libro, el primero de una colección que espero sea vasto, son la evidencia de que, aun cuando el ambiente se vuelve denso y la naturaleza parece ser la distopia que tantas veces la imaginación nos había anunciado, nos seguimos preguntando por cómo actuamos, por cuál es la respuesta que nos exige el mundo. Entre textos y fotos, asistimos a nuevas representaciones de la realidad que nos agobia y nos sorprende. Entre textos y fotos, nos conmovemos por la mirada de esos otros que se atrevieron, con valentía y generosidad, a mostrarnos una arista de sus vidas. Este libro es también, una invitación. En cada una de las irrupciones de los autores encontramos una provocación para cuestionar la hegemonía, esa que nos trastoca sin siquiera intentar persuadirnos, de la que somos cómplices cuando no cuestionamos. Una invitación para preguntarnos desde la palabra del otro, cuál es nuestra propia respuesta a los tiempos aciagos que nos abruman. Cuál es ese lugar desde donde le rebatimos al mundo por nuestra autonomía. Cuál es, en definitiva, nuestra contestación a la vida.

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.

The challenge was to achieve more reservoir contact in a cretaceous tight reservoir to improve production and maximize recovery. Multilateral well campaigns were performed to meet these objectives.This case study describes an effective workflow for performing openhole sidetracks in this challenging medium-hard carbonate formation. The workflow maintained reservoir contact and achieved the desired production objectives.Two 6-in. multilateral drain sections were successfully drilled by performing openhole sidetrack using the continuous proportional steering method (CPSM). This method is not new to the industry, but this case study describes the systematic, unique workflow that was designed and followed to ensure a successful sidetrack in this low-porosity, hard formation.The sidetrack implementation started by creating humps at inclinations ranging from 88 to 91 degrees into the formation in the original 6-in. section. These humps were confirmed using near-bit inclination data (4.5 ft from the bit) and were identified as the sites for initiating a sidetrack. This paper discusses the best practices that were key to the successful execution of the project in one run on the first attempt.After the sidetrack, use of appropriate combinations of shallow and deep logging-while-drilling (LWD) measurements in the same bottom hole assembly (BHA) enabled the direct geosteering of the well, exposing more reservoir surface area than planned.A reduction of 10% from the planned well duration was achieved. Two 6-in. laterals, each approximately 4000 ft, were drilled in a single run and 100% reservoir contact was achieved.This experience proved that planning and precise execution could enable drilling of openhole sidetracks, even through hard formations. These sidetracks can then achieve fishbone wells with desired reservoir contact and realize the field development objectives in a technically robust and cost-efficient manner.CPSM does not rely on a pressure drop for steering. Although this proof of concept was performed in a relatively hard formation, similar workflows with appropriate drilling engineering may be applied to less-competent formations as well. The detailed procedure and flowchart created from the experience with the sample well can be adopted for use in similar applications.

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

We analyse high-resolution optical spectra of a sample of low-mass, very young, mid-to late M stellar and substellar objects in Upper Scorpius and Taurus. Precise effective temperatures (± 50K) and surface gravities (± 0.25 dex) are derived from amulti-feature spectral analysis using TiO, NaI and KI, through comparison with the latest synthetic spectra. Our high-resolution analysis is independent of extinction estimates. Combining our Teff and gravities with distance and photometry information then allows us to derive extinctions, masses, radii and luminosities. We emphasize that our analysis is independent of theoretical evolutionary models. As such, it offers a new way of deriving fundamental parameters for low-mass stellar and substellar objects, and of testing the model evolutionary tracks. We find discrepancies between our results and the theoretical tracks for the coolest, lowest mass targets. Our gravities for these objects are significantly (∼ 0.75 dex) lower than for hotter ones. This is at odds with the predictions of the evolutionary models, and causes improbably low ages to be derived from the theoretical tracks for the coolest objects. Similarly, our radii and luminosities for the coolest, lowest mass objects are much larger than predicted by the evolutionary models. These results lead us to suggest that significant improvements in the evolutionary models may be necessary for very cool, ultra-low mass objects, perhaps in the treatment of convection and/or initial conditions. We also find two of our coolest targets to be planetary mass objects (“planemos”), with mass ∼ 7 MJ. Thus, some late-M PMS objects may be much less massive than current evolutionary models indicate. Equivalently, young planemos may be more luminous than expected. Combined with the detection of planemos by other groups, our results imply that such objects may not be too rare.

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.