Breve historia de la ciencia del cambio climático y la respuesta política global: un análisis contextual/Brief history of climate change science and global political response: a context analysis

Los sistemas naturales y humanos de la Tierra soportan presiones dramáticas debido al cambio climático. Una gran cantidad de evidencia científica muestra que el cambio climático es, en parte, causado por actividades antropogénicas. El inicio de la revolución industrial, alrededor de 1750, intensificó la tasa de acumulación de gases de efecto invernadero (GEI) en la atmósfera terrestre. Este aumento de la concentración de GEI en la atmósfera, sin duda, ha acelerado los cambios en el clima del planeta, causando a su vez un aumento de las temperaturas globales del suelo, los océanos y el aire. Este aumento de la temperatura global afecta notablemente a los sistemas naturales y humanos por igual. Científicos, sectores interesados, personalidades sociales y políticas han exigido a los gobiernos y otras organizaciones locales, nacionales y supranacionales que acepten su responsabilidad y emprendan acciones decisivas para mitigar el cambio climático y sus impactos. Actualmente, uno de los principales objetivos de la humanidad, para minimizar o evitar desastres catastróficos relacionados con el clima, es mantener el calentamiento global por debajo de los 2∘ C en comparación con los niveles preindustriales. En consecuencia, la comunidad internacional ha respondido de diferentes maneras para mitigar y adaptarse a los impactos del cambio climático. Este artículo presenta un análisis de la literatura sobre la ciencia del cambio climático y la respuesta política global, proporcionando, además, una descripción del establecimiento de diferentes organizaciones científicas y políticas clave destinadas a mitigar el cambio climático. Abstract: Earth’s natural and human systems are enduring dramatic pressures due to climate change. A great body of scientific evidence shows that climate change is, in part, caused by anthropogenic activities. The start of the industrial revolution, around 1750, intensified the rate of growth of GHGs’ concentration in Earth’s atmosphere. The increased atmospheric GHGs’ concentration has, undoubtedly, accelerated changes in Earth’s climate, which in turn, caused an increase of global land, ocean, and air temperatures. This global temperature rise is noticeably impacting natural and human systems alike. Scientists, stakeholders, social and political personalities have demanded governments and other organizations at local, national and supranational levels to accept their responsibility and undertake decisive actions to mitigate climate change and its impacts. At present, one of the main goals of humankind, to minimize or avoid catastrophic climate-related disasters, is to keep earth’s warming below 2∘ C compared to pre-industrial levels. In this context, the international community has responded in different ways to mitigate and adapt to the impacts of climate change. This paper presents a brief review of the literature of the science of climate change and the global political response. Science and political response must go hand in hand to fight climate change and its impacts. This paper also provides an account of the establishment of different key scientific and political organizations aimed to mitigate climate change. Palabras clave: Cambio Climático, Ciencia Medioambiental, Política Medioambiental. Keywords: Climate Change, Environmental Science, Environmental Policy

Inspiration Mining: Intersecting Improbable Connections in a New Landscape of Cultural Reflection and Influence

This article aims to present a critical reflection on the collaborative curatorship of the exhibition “Intersecting Improbable Connections”. It is a transdisciplinary exhibition covering architecture, design, arts, among other fields, and calls for non-linear productive thinking strategies. It explores the intersection of unlikely relationships to inspire memorable visits to museums, and it feeds the Inspædia platform, creating a new landscape of reflection and cultural influence. It advocates a new concept of exhibition curation that minimizes costs (because it does not involve transportation or insurance for the pieces) and is intended to help stimulate creative processes. Based on a selection of content from the participating museums’ permanent exhibitions, duly marked with QR Codes, visitors can access that content that is already available on the Inspædia platform and explore potentially endless connections, without losing contact with the physical object (and vice versa).FCT – Fundação para a Ciência e a Tecnologia, in the scope of the projects SFRH/BPD/98427/2013, UID/EAT/04008/ 2019, and UID/AUR/04026/201

Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. V.: A Massive Jupiter orbiting the very low metallicity giant star BD+03 2562 and a possible planet around HD~103485

We present two evolved stars from the TAPAS (Tracking Advanced PlAnetary Systems) with HARPS-N project devoted to RV precision measurements of identified candidates within the PennState - Torun Centre for Astronomy Planet Search. Evolved stars with planets are crucial to understand the dependency of the planet formation mechanism on the mass and metallicity of the parent star and to study star-planet interactions. The paper is based on precise radial velocity (RV) measurements, for HD 103485 we collected 57 epochs over 3317 days with the Hobby-Eberly Telescope and its High Resolution Spectrograph and 18 ultra-precise HARPS-N data over 919 days. For BD+03 2562 we collected 46 epochs of HET data over 3380 days and 19 epochs of HARPS-N data over 919 days. We present the analysis of the data and the search for correlations between the RV signal and stellar activity, stellar rotation and photometric variability. Based on the available data, we interpret the RV variations measured in both stars as Keplerian motion. Both stars have masses close to Solar (1.11 and 1.14), very low metallicities ([Fe/H]=-0.50 and -0.71), and, both have Jupiter planetary mass companions (m sin i=7 and 6.4 Mj), in close to terrestrial orbits (1.4 and 1.3~au), with moderate eccentricities (e=0.34 and 0.2). However, we cannot totally exclude that the signal in the case of HD~103485 is due to rotational modulation of active regions. Based on the current data, we conclude that BD+03 2562 has a bona fide planetary companion while for HD 103485 we cannot totally exclude that the best explanation for the RV signal modulations is not the existence of a planet but stellar activity. If, the interpretation remains that both stars have planetary companions they represent systems orbiting very evolved stars with very low metallicities, a challenge to the conditions required for the formation of massive giant gas planets.Comment: Acepted A&A 12 pages, 11 figure

Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean

0000-0002-7993-1523© 2015 Riesgo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

Dynamical evolution of two-planet systems and its connection with white dwarf atmospheric pollution

Asteroid material is detected in white dwarfs (WDs) as atmospheric pollution by metals, in the form of gas/dust discs, or in photometric transits. Within the current paradigm, minor bodies need to be scattered, most likely by planets, into highly eccentric orbits where the material gets disrupted by tidal forces and then accreted onto the star. This can occur through a planet-planet scattering process triggered by the stellar mass loss during the post main-sequence evolution of planetary systems. So far, studies of the $N$-body dynamics of this process have used artificial planetary system architectures built ad hoc. In this work, we attempt to go a step further and study the dynamical instability provided by more restrictive systems, that, at the same time allow us an exploration of a wider parameter space: the hundreds of multiple planetary systems found around main-sequence (MS) stars. We find that most of our simulated systems remain stable during the MS, Red and Asymptotic Giant Branch and for several Gyr into the WD phases of the host star. Overall, only $\approx$ 2.3$\%$ of the simulated systems lose a planet on the WD as a result of dynamical instability. If the instabilities take place during the WD phase most of them result in planet ejections with just 5 planetary configurations ending as a collision of a planet with the WD. Finally 3.2$\%$ of the simulated systems experience some form of orbital scattering or orbit crossing that could contribute to the pollution at a sustained rate if planetesimals are present in the same system.Comment: 18 pages, 14 figure

Do instabilities in high-multiplicity systems explain the existence of close-in white dwarf planets?

We investigate the origin of close-in planets and related phenomena orbiting white dwarfs (WDs), which are thought to originate from orbits more distant from the star. We use the planetary architectures of the 75 multiple-planet systems (four, five and six planets) detected orbiting main-sequence stars to build 750 dynamically analogous templates that we evolve to the WD phase. Our exploration of parameter space, although not exhaustive, is guided and restricted by observations and we find that the higher the multiplicity of the planetary system, the more likely it is to have a dynamical instability (losing planets, orbit crossing and scattering), that eventually will send a planet (or small object) through a close periastron passage. Indeed, the fraction of unstable four- to six-planet simulations is comparable to the 25-50$\%$ fraction of WDs having atmospheric pollution. Additionally, the onset of instability in the four- to six-planet configurations peaks in the first Gyr of the WD cooling time, decreasing thereafter. Planetary multiplicity is a natural condition to explain the presence of close-in planets to WDs, without having to invoke the specific architectures of the system or their migration through the von Zeipel-Lidov-Kozai (ZLK) effects from binary companions or their survival through the common envelope phase.Comment: 5 pages, 4 figures, 1 table, accepted to MNRAS Letter

Pasado, presente y futuro del búfalo en Argentina

El búfalo comenzó a ser introducido al país a comienzo el siglo XX, mediante la importación razas Mediterránea, Murrah y Jafarabadi. En la actualidad la población bubalina alcanzó las de 87.711 cabezas y se encuentran distribuidas en 20 de las 23 provincias que componen el territorio nacional. El 80 % de la población de búfalos se encuentran en el nordeste argentino. Siendo las provincias de Formosa y Corrientes las que cuentan con la mayores poblaciones bubalinas. Existen en el país 8 millones de hectáreas aptas para soportar una carga de 4 millones de búfalos.The buffalo began to be introduced to the country in the early twentieth century, by importing Mediterranean, Murrah and Jafarabadi breeds. Today buffalo population reached 87.711 heads, which are distributed in 20 out of the 23 provinces that conforms the country. The 80% of the population of buffaloes is found in northeastern region, being the provinces of Formosa and Corrientes those with the largest buffalo population. The country has 8 million hectares suitable to withstand a load of 4 million buffaloes.Fil: Crudeli, G. A.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Patiño, E. M.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Maldonado Vargas, P.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Konrad, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; Argentin

Quasienergy spectrum and tunneling current in ac-driven triple quantum dot shuttles

The dynamics of electrons in ac driven double quantum dots have been extensively analyzed by means of Floquet theory. In these systems, coherent destruction of tunneling has been shown to occur for certain ac field parameters. In the present work we analyze, by means of Floquet theory, the electron dynamics of a triple quantum dot in series attached to electric contacts, where the central dot position oscillates. In particular, we analyze the quasienergy spectrum of this ac driven nanoelectromechanical system, as a function of the intensity and frequency of the ac field and of external dc voltages. For strong driving fields, we derive, by means of perturbation theory, analytical expressions for the quasienergies of the driven oscillator system. From this analysis we discuss the conditions for coherent destruction of tunneling (CDT) to occur as a function of detuning and field parameters. For zero detuning, and from the invariance of the Floquet Hamiltonian under a generalized parity transformation, we find analytical expressions describing the symmetry properties of the Fourier components of the Floquet states under such transformation. By using these expressions, we show that in the vicinity of the CDT condition, the quasienergy spectrum exhibits exact crossings which can be characterized by the parity properties of the corresponding eigenvectors