Paying the forest for electricity: A modelling framework to market forest conservation as payment for ecosystem services benefiting hydropower generation

Published in PESC Special issue: Payments for ecosystem services in conservation: performance and prospectsThe operation and longevity of hydropower dams are often negatively impacted by sedimentation. Forest conservation can reduce soil erosion, and therefore efforts to maintain upstream forest cover within a watershed contribute to the economic life span of a hydropower facility. The cost of forest conservation can be viewed as an investment in hydropower and be financed via a payment for ecosystem services (PES) scheme. A novel modelling framework is used to estimate payments for forest conservation consisting of: (1) land-use change projection; (2)watershed erosion modelling; (3) reservoir sedimentation estimation; (4) power generation loss calculation; and (5) PES scheme design. The framework was applied to a proposed dam in Cambodia (Pursat 1). The estimated net present value of forest conservation was US$4.7 million when using average annual climate values over 100 years, or US$ 6.4 million when considering droughts every eight years. This can be remunerated with annual payments ofUS$4.26ha-1 or US$ 5.78ha-1, respectively, covering forest protection costs estimated at US$ 0.9 ha-1 yr-1. The application of this type of PES represents a rational option that allows for conservation and development of hydropower watersheds susceptible to erosion and sedimentation

One hundred years of solitude, accumulation and violence: A comparative historical analysis of the Sierra Nevada of Santa Marta Valley

This is an analysis of two moments in the Colombian history within a century of difference, where isolation, accumulation and violence interact in a region brought into the worlds’ imaginary by the Colombian novelist Gabriel García Márquez in One Hundred years of Solitude. A valley between four natural borderlines: the Sierra Nevada of Santa Marta, the Perijá hills, the Central and East ‘Cordilleras’ -mountain range- and the Magdalena River in the departments of Cesar and Magdalena (Colombia) part of what was called the department of ‘Magdalena Grande’ was blessed – or perhaps coursed – with wealth in natural resources; plenty of water streams, a unique biodiversity, cultural affluence and immense reserves of one of the purest steam coals. This paper attempts to draw a picture of the superimposed and persistent power structures that apparently facilitate the accumulative processes and imbalances within one century of difference, making use of violence as means to maintain equilibrium. Environment is changed trough politicized violent inflictions over society and nature. The resultant scars are the ones inflicted on a collective memory, as this valley is and will always be recalled by the poetic truth of the narrative of Gabriel García Marquez who recreated this mythic environment as ‘Macondo’. He remembers his own story of early childhood that here serves as an excuse to analyze a region that is again being bled by accumulation

Discovery of the first B[e] supergiants in M 31

B[e] supergiants (B[e]SGs) are transitional objects in the post-main sequence evolution of massive stars. The small number of B[e]SGs known so far in the Galaxy and the Magellanic Clouds indicates that this evolutionary phase is short. Nevertheless, the strong aspherical mass loss occurring during this phase, which leads to the formation of rings or disk-like structures, and the similarity to possible progenitors of SN1987 A emphasize the importance of B[e]SGs for the dynamics of the interstellar medium as well as stellar and galactic chemical evolution. The number of objects and their mass-loss behavior at different metallicities are essential ingredients for accurate predictions from stellar and galactic evolution calculations. However, B[e]SGs are not easily identified, as they share many characteristics with luminous blue variables (LBVs) in their quiescent (hot) phase. We present medium-resolution near-infrared K-band spectra for four stars in M 31, which have been assigned a hot LBV (candidate) status. Applying diagnostics that were recently developed to distinguish B[e]SGs from hot LBVs, we classify two of the objects as bonafide LBVs; one of them currently in outburst. In addition, we firmly classify the two stars 2MASS J00441709+4119273 and 2MASS J00452257+4150346 as the first B[e]SGs in M 31 based on strong CO band emission detected in their spectra, and infrared colors typical for this class of stars.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

El aclareo en fruto: ¿una nueva fuente de compuestos funcionales?

Estudio del contenido en compuestos antioxidantes de los frutos preocedentes del aclareo del melocotón, nectarina y paraguay

Mechanical Identities of RNA and DNA Double Helices Unveiled at the Single-Molecule Level

[EN] Double-stranded (ds) RNA is the genetic material of a variety of viruses and has been recently recognized as a relevant molecule in cells for its regulatory role. Despite that the elastic response of dsDNA has been thoroughly characterized in recent years in single-molecule stretching experiments, an equivalent study with dsRNA is still lacking. Here, we have engineered long dsRNA molecules for their individual characterization contrasting information with dsDNA molecules of the same sequence. It is known that dsRNA is an A-form molecule unlike dsDNA, which exhibits B-form in physiological conditions. These structural types are distinguished at the single-molecule level with atomic force microscopy (AFM) and are the basis to understand their different elastic response. Force¿extension curves of dsRNA with optical and magnetic tweezers manifest two main regimes of elasticity, an entropic regime whose end is marked by the A-form contour- length and an intrinsic regime that ends in a low-cooperative overstretching transition in which the molecule extends to 1.7 times its A-form contour-length. DsRNA does not switch between the A and B conformations in the presence of force. Finally, dsRNA presents both a lower stretch modulus and overstretching transition force than dsDNA, whereas the electrostatic and intrinsic contributions to the persistence length are larger.This work was supported by grants from the Spanish Ministry of Science and Innovation (BFU2011-29038 and BFU2010-15703) and the Comunidad de Madrid (S2009/MAT/1507). IRA.-G. acknowledges a Ramon y Cajal contract from the Spanish Ministry of Science and Innovation (RYC-2007-01765). Work in the F.M.-H. laboratory was supported by a Starting Grant from the European Research Council (no. 206117) and a grant from the Spanish Ministry of Science and Innovation (FIS2011-24638). We thank M. S. Dillingham for kindly providing the pSP73-JY0 plasmid, M. Menendez for access to a spectropolarimeter, A. Monserrate for polylysine-AFM control experiments, and B. Ibarra for fruitful discussions.Herrero-Galán, E.; Fuentes-Perez. M.E.; Carrasco, C.; Valpuesta, J.; Carrascosa, J.; Moreno-Herrero, F.; Arias-Gonzalez, JR. (2013). Mechanical Identities of RNA and DNA Double Helices Unveiled at the Single-Molecule Level. Journal of the American Chemical Society. 135(1):122-131. https://doi.org/10.1021/ja3054755S122131135

Discovery of the first B[e] supergiants in M 31

B[e] supergiants (B[e]SGs) are transitional objects in the post-main sequence evolution of massive stars. The small number of B[e]SGs known so far in the Galaxy and the Magellanic Clouds indicates that this evolutionary phase is short. Nevertheless, the strong aspherical mass loss occurring during this phase, which leads to the formation of rings or disk-like structures, and the similarity to possible progenitors of SN1987 A emphasize the importance of B[e]SGs for the dynamics of the interstellar medium as well as stellar and galactic chemical evolution. The number of objects and their mass-loss behavior at different metallicities are essential ingredients for accurate predictions from stellar and galactic evolution calculations. However, B[e]SGs are not easily identified, as they share many characteristics with luminous blue variables (LBVs) in their quiescent (hot) phase. We present medium-resolution near-infrared K-band spectra for four stars in M 31, which have been assigned a hot LBV (candidate) status. Applying diagnostics that were recently developed to distinguish B[e]SGs from hot LBVs, we classify two of the objects as bonafide LBVs; one of them currently in outburst. In addition, we firmly classify the two stars 2MASS J00441709+4119273 and 2MASS J00452257+4150346 as the first B[e]SGs in M 31 based on strong CO band emission detected in their spectra, and infrared colors typical for this class of stars.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

“Análisis en profundidad de las narrativas que hacen, egresados y docentes directores, acerca del proceso de elaboración de tesinas”

Esta investigación pretende dar cuenta de la problemática que constituye, al interior de lasinstituciones académicas de grado, la elaboración de una tesina para la obtención de lastitulaciones. Se indagó en los relatos de egresados y directores o tutores de tesina, acerca decómo fue el proceso de elaboración de estas, a fin de comprender y sistematizar susperspectivas. Las Licenciaturas en Minoridad, Psicología y Criminalística, Facultad dePsicología, UDA, constituyen el marco del estudio