Modelamiento de presiones sobre la biodiversidad en la Guayana

Este artículo busca identificar los factores que han influido a que la transformación de ecosistemas y la deforestación avancen en 4 zonas del sector Guayanes de la Amazonía Colombiana (La Macarena, Nukak, Puinawai y Chiribiquete). Para la identificación de estos factores, se realizó un análisis en dos escalas: a nivel municipal y a nivel de píxel, los análisis con datos municipales sirvieron para dar un contexto de los aspectos sociales y demográficos para cada una de las zonas, adicionalmente se realizó un análisis de correlaciones. Los datos a nivel de píxel se utilizaron para la estimación de modelos de regresión logística para cada zona, de forma complementaria y para tener en cuenta la dinámica de cambio y los efectos de vecindad entre pixeles se realizó un ejercicio de simulación empleando el software DINAMICA (desarrollado por el centro de sensores remotos de la Universidad de Minas Gerais) para las dos zonas de mayor transformación. Los resultados del análisis de asociaciones, modelamiento y simulación evidencian que la facilidad de acceso terrestre (distancia a vías), el estado legal del territorio, la distancia a centros urbanos (distancia a cabeceras) son los factores relevantes que han impulsado la transformación de ecosistemas y la deforestación en el área de análisis.Ecosystem change and deforestation has advanced in four areas of the Guayanes region of the Colombian Amazon (La Macarena, Nukak, Puinawai and Chiribiquete). This paper aims to identify which factors have influenced these changes, by undertaking analyses on both municipal and pixel levels. The analyses of municipal data provide the social and demographic context for each area. In addition, a correlation analysis is carried out. Pixel level data is used to estimate logistic regression models for each area. Moreover, to take into account the dynamics of change and the effects of proximity between pixels, a simulation exercise is undertaken using DINAMICA software (developed at the Remote Sensor Centre of the Federal University of Minas Gerais) to analyse the two areas that underwent the most change. The results of the association, modelling and simulation analyses reveal that the following factors have driven ecosystem change and deforestation in the study area: ease of land access (distance from roads), the legal status of the territory and the distance from urban centres (the distance from administrative centres)

Caso de estudio CCNA2.

Una subred es un conjunto de direcciones IP y con ella podemos hacer dos cosas: asignar direcciones IP a los equipos o dividirlo nuevamente en subredes más pequeñas. En cada división, las subredes primera y última no se usan (actualmente, la mayoría del hardware ya soporta el poder trabajar con ambas, primera y última, aunque se deberá de comprobar antes de hacer uso de estas). Este tipo tiene una aplicación parecida al direccionamiento IP donde la primera identificaba la red y la última es de broadcast - en este caso, la primera identificaba la subred y la última se aplicaba al broadcast de subred. Cabe aclarar que no se usan para asignar direcciones IP a los equipos, pero sí se pueden usar para dividirlas en subredes más pequeñas.A subnet is a set of IP addresses and with it we can do two things: assign IP addresses to computers or divide it back into subnets more little. In each division, the first and last subnets are not used (currently, the Most hardware already supports working with both, first and last, although you should check before using these). This guy has an application similar to the IP address where the first one identified the network and the last one is from broadcast - in this case, the first one identified the subnet and the last one was applied to the subnet broadcast It should be noted that they are not used to assign IP addresses to computers, but they can be used to divide them into smaller subnets

Methane dry reforming over Ni supported on pine sawdust activated carbon: Effects of support surface properties and metal loading

The influence of metal loading and support surface functional groups (SFG) on methane dry reforming (MDR) over Ni catalysts supported on pine-sawdust derived activated carbon were studied. Using pine sawdust as the catalyst support precursor, the smallest variety and lowest concentration of SFG led to best Ni dispersion and highest catalytic activity, which increased with Ni loading up to 3 Ni atoms nm-2. At higher Ni loading, the formation of large metal aggregates was observed, consistent with a lower "apparen" surface area and a decrease in catalytic activity. The H2/CO ratio rose with increasing reaction temperature, indicating that increasingly important side reactions were taking place in addition to MDR.Financial support was provided by CONICYT PFB-27 project (UDT-University of Concepción) and FONDECYT 1100884 grant

Efecto insectistático de extractos etanólicos de clavo y pimienta en Trialeurodes vaporariorum West. (Hemiptera: Aleyrodidae)

In the management the greenhouse whitefly, Trialeurodes vaporariorum, organosynthetic pesticides are commonly used, increasing the frequency and doses of application, thus generating resistance of the pest to pesticides and eliminating natural enemies. Then, this make necessary to search for alternatives that contribute to solve the whitefly problem without deteriorating the environment at must. Among several options, bioassays were established applying ethanol extracts of clove Syzygium aromaticum and pepper Pimenta dioica to the leaves of tomato plants where 2-day-old adults were released in a bioassay, and on another set of tomato plants oviposition was previously induced for 3 d. Mortality of adults and laid eggs, as well as hatched eggs were recorded. The 1.0% clove extracts caused 33.7 adult mortality, 72.9% oviposition inhibition with CIO50 of 0.19, and pepper extracts caused 32.5% adult mortality, 65.8% oviposition inhibition with CIO50´s of 0.46%, and both inhibited from 52.6 to 100% hatching with CIE50´s from 0.11 to 0.71% respectively, it being total when 1.0% pepper extract is applied to 2-day-old eggs. It is suggested that activity of the clove and pepper ethanol extracts is mainly insectistatic, although it can have an ovicide effect, it is a biorational input to be integrated into the ecological management of the greenhouse whitefly.En el manejo de la mosca blanca Trialeurodes vaporariorum generalmente se hace uso de plaguicidas organosintéticos, aumentando cada vez más la frecuencia y la dosis de aplicación, lo que provoca resistencia en la plaga a los plaguicidas y eliminación de enemigos naturales, por lo que es imprescindible la búsqueda de alternativas que contribuyan a resolver el problema, sin deterioro del ambiente. Entre las diversas opciones, en los bioensayos se aplicaron al follaje de tomate los extractos etanólicos de clavo Syzygium aromaticum y pimienta Pimenta dioica, en plantas donde previamente se liberaron adultos de 2 d y en otras plantas se indujo la oviposición por 3 d. En estos bioensayos se registró la mortalidad de adultos y huevos ovipositados, así como huevos eclosionados. Los extractos al 1.0% de clavo causan 33.7% de mortalidad de adultos, 72.9% de inhibición de oviposición con CIO50 de 0.19, y de pimienta causan 32.5% de mortalidad de adultos; 65.8% de inhibición de oviposición; con CIO50 0.46% y ambos extractos inhiben de 52.6 a 100% la eclosión de los huevos de mosca blanca con CIE50´s de 0.11 a 0.71% respectivamente, siendo total cuando se aplica el extracto de pimienta al 1.0% a huevos de 2 d de edad. La actividad de los extractos etanólicos de clavo y pimienta, principalmente insectistática; aunque puede llegar a tener efecto ovicida, es una aportación biorracional para integrarse al manejo ecológico de mosca blanca

Erythrocyte values, pulmonary arterial pressure and right ventricle weight in broiler chicken of two commercial lines under intensive breeding at sea level

El estudio tuvo como objetivo determinar la asociación entre valores eritrocíticos, presión arterial pulmonar media y las relaciones cardiacas ventriculares en las líneas de aves Cobb-Vantres (CV) y Ross (R) bajo crianza intensiva a nivel del mar. Se utilizaron 61 aves de 35 días de edad por línea. Se determinó peso corporal (PC), hematocrito (Ht), hemoglobina (Hb), número de glóbulos rojos (GR), presión arterial pulmonar media (PaPm) y las relaciones ventrículo derecho/ventrículo total (VD/VT), ventrículo izquierdo/ ventrículo total (VI/VT), ventrículo derecho/peso corporal (VD/PC), ventrículo izquierdo/ peso corporal (VI/PC) y ventrículo total/peso corporal (VT/PC). Las aves de la línea CV presentaron un peso (2.201 kg) y VI/VT (0.822) mayor que la línea R (2.060 kg y 0.793, respectivamente) (p<0.05), mientras que la línea R presentó mayores valores de Ht (29.39%), Hb (10.92 g/dl), VD/VT (0.207), VD/PC (0.753) y VT/PC (3.659) que CV (25.84%, 10.25 g/dl, 0.178, 0.615 y 3.462, respectivamente) (p<0.05). La PaPm fue estadísticamente similar en ambas líneas (CV: 15.96; R: 17.34 mmHg). Los resultados indican que ambas líneas presentan un buen comportamiento cardiorespiratorio.The aim of the study was to determine the association between erythrocyte values, pulmonary arterial pressure and ventricular cardiac relationships in Cob-Vantress (CV) and Ross (R) lines under intensive breeding at sea level. It was used 61 birds of 35 days of age per line. Body weight (BW), hematocrit (Ht), hemoglobin (Hb), erythrocyte count (E), pulmonary arterial pressure (PaPm), and rates among weights of right ventricle/total ventricle (RV/TV), left ventricle/total ventricle (LV/TV), right ventricle/body weight (RV/ BW), left ventricle/body weight (LV/BW), and total ventricle/body weight (TV/BW). Birds of line CV showed that BW (2.201 kg) and LF/TV (0.822) were greater that in line R (2.060 kg and 0.793 respectively) (p<0.05), whereas line R showed greater values of Ht (29.39%), Hb (10.92 g/dl), RV/TV (0.207), RV/BW (0.753), and TV/BW (3.659) than CV (25.84%, 10.25 g/dl, 0.178, 0.615, and 3.462, respectively) (p<0.05). PaPm was statistically similar for both lines (CV: 15.96; R: 17.34 mmHg). The results showed that chickens of both lines had a good cardiopulmonary performance

A Transiting, Temperate Mini-Neptune Orbiting the M Dwarf TOI-1759 Unveiled by TESS

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.-- Full list of authors: Espinoza, Néstor; Pallé, Enric; Kemmer, Jonas; Luque, Rafael; Caballero, José A.; Cifuentes, Carlos; Herrero, Enrique; Sánchez Béjar, Víctor J.; Stock, Stephan; Molaverdikhani, Karan; Morello, Giuseppe; Kossakowski, Diana; Schlecker, Martin; Amado, Pedro J.; Bluhm, Paz; Cortés-Contreras, Miriam; Henning, Thomas; Kreidberg, Laura; Kürster, Martin; Lafarga, Marina; Lodieu, Nicolas; Morales, Juan Carlos; Oshagh, Mahmoudreza; Passegger, Vera M.; Pavlov, Alexey; Quirrenbach, Andreas; Reffert, Sabine; Reiners, Ansgar; Ribas, Ignasi; Rodríguez, Eloy; López, Cristina Rodríguez; Schweitzer, Andreas; Trifonov, Trifon; Chaturvedi, Priyanka; Dreizler, Stefan; Jeffers, Sandra V.; Kaminski, Adrian; López-González, María José; Lillo-Box, Jorge; Montes, David; Nowak, Grzegorz; Pedraz, Santos; Vanaverbeke, Siegfried; Zapatero Osorio, Maria R.; Zechmeister, Mathias; Collins, Karen A.; Girardin, Eric; Guerra, Pere; Naves, Ramon; Crossfield, Ian J. M.; Matthews, Elisabeth C.; Howell, Steve B.; Ciardi, David R.; Gonzales, Erica; Matson, Rachel A.; Beichman, Charles A.; Schlieder, Joshua E.; Barclay, Thomas; Vezie, Michael; Villaseñor, Jesus Noel; Daylan, Tansu; Mireies, Ismael; Dragomir, Diana; Twicken, Joseph D.; Jenkins, Jon; Winn, Joshua N.; Latham, David; Ricker, George; Seager, Sara.We report the discovery and characterization of TOI-1759 b, a temperate (400 K) sub-Neptune-sized exoplanet orbiting the M dwarf TOI-1759 (TIC 408636441). TOI-1759 b was observed by TESS to transit in Sectors 16, 17, and 24, with only one transit observed per sector, creating an ambiguity regarding the orbital period of the planet candidate. Ground-based photometric observations, combined with radial-velocity measurements obtained with the CARMENES spectrograph, confirm an actual period of 18.85019 ± 0.00014 days. A joint analysis of all available photometry and radial velocities reveals a radius of 3.17 ± 0.10 R⊕ and a mass of 10.8 ± 1.5 M⊕. Combining this with the stellar properties derived for TOI-1759 (R⋆ = 0.597 ± 0.015 R⊙; M⋆ = 0.606 ± 0.020 M⊙; Teff = 4065 ± 51 K), we compute a transmission spectroscopic metric (TSM) value of over 80 for the planet, making it a good target for transmission spectroscopy studies. TOI-1759 b is among the top five temperate, small exoplanets (Teq 200 days seem to be present in our radial velocities. While our data suggest both could arise from stellar activity, the later signal's source and periodicity are hard to pinpoint given the ∼200 days baseline of our radial-velocity campaign with CARMENES. Longer baseline radial-velocity campaigns should be performed in order to unveil the true nature of this long-period signal. © 2022. The Author(s). Published by the American Astronomical Society.CARMENES is an instrument at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (Almería, Spain), operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC). CARMENES was funded by the Max-Planck-Gesellschaft (MPG), the Consejo Superior de Investigaciones Científicas (CSIC), the Ministerio de Economía y Competitividad (MINECO), and the European Regional Development Fund (ERDF) through projects FICTS-2011-02, ICTS-2017-07-CAHA-4, and CAHA16-CE-3978, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciëncies de l'Espai, Institut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Centro de Astrobiología, and Centro Astronómico Hispano-Alemán), with additional contributions by the MINECO, the Deutsche Forschungsgemeinschaft through the Major Research Instrumentation Programme and Research Unit FOR2544 "Blue Planets around Red Stars," the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía. This work was based on data from the CARMENES data archive at CAB (CSIC-INTA). We acknowledge financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades and the ERDF through projects PID2019-109522GB-C5[1:4], PGC2018-098153-B-C33, AYA2018-84089, PID2019-107061GB-C64, PID2019-110689RB-100, AYA2016-79425-C3-1/2/3-P, and BES-2017-080769, and the Centre of Excellence "Severo Ochoa" and "María de Maeztu" awards to the Instituto de Astrofísica de Canarias (CEX2019-000920-S), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737), NASA (NNX17AG24G), and the Generalitat de Catalunya/CERCA program. Data were partly collected with the 90 cm telescope at the Sierra Nevada Observatory (SNO) operated by the Instituto de Astrofí fica de Andalucí a (IAA, CSIC). We acknowledge the telescope operators from the Sierra Nevada Observatory for their support. G.M. has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 895525. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products.Peer reviewe

Biocatalytic routes to stereo-divergent iridoids

Thousands of natural products are derived from the fused cyclopentane-pyran molecular scaffold nepetalactol. These natural products are used in an enormous range of applications that span the agricultural and medical industries. For example, nepetalactone, the oxidized derivative of nepetalactol, is known for its cat attractant properties as well as potential as an insect repellent. Most of these naturally occurring nepetalactol-derived compounds arise from only two out of the eight possible stereoisomers, 7S-cis-trans and 7R-cis-cis nepetalactols. Here we use a combination of naturally occurring and engineered enzymes to produce seven of the eight possible nepetalactol or nepetalactone stereoisomers. These enzymes open the possibilities for biocatalytic production of a broader range of iridoids, providing a versatile system for the diversification of this important natural product scaffold

El sistema financiero del siglo xxi a partir de la Ley 45 de 1990

La Ley 45 de 1990 representa un momento estelar en la historia de la legislación financiera de Colombia. Pero abarcó mucho más: reguló la actividad aseguradora, incursionó en el contrato de seguro, reguló el sistema previsional y delineó el régimen bursátil. Así mismo, anticipó lineamientos de lo que sería, un año después, la consagración de tales actividades -financiera, aseguradora, bursátil y previsional- como de rango constitucional. Este libro recoge las reflexiones de expertos sobre las diversas temáticas abordadas en dicha ley, con la visión enriquecida derivada del transcurso de 20 años, de varias legislaciones adicionales y de algunas crisis nacionales y foráneas. Escrutar en su veintenario es un ejercicio válido y oportuno, tanto más como que al haber renovado los arquetipos de la legislación precedente, sirvió además como referente de empeños de enmienda normativas de otros países de la región y de los organismos multilaterales

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure