100 artigos que devem/podem ser lidos realmente por todos os ecólogos?

Reading scientific articles is fundamental for researchers, not only to keep pace with advances in their field, but also to know those giants on whose shoulders they are standing. In this sense, Courchamp and Bradshaw (2018) recently proposed a list of 100 seminal papers deemed to be of major importance in ecology, thus providing a general ‘must-read’ list for any new ecologist. The authors metaphorically speak of ecology as an ever-growing brick wall of published evidence. In order to quantify the degree of interference of the paywall over the wall of science, we took the opportunity given by the 100 seminal papers list and registered how many articles have been made universally and freely available by the publisher. Of the 100 scientific papers proposed as foundations of the wall of ecological knowledge, 66 are behind the paywall, with a total cost of US$1,560. This paywall exacerbates the existing asymmetries in ecological research between researchers from developed countries and the Global South. Diversity in research, as in ecological systems, is a source of robustness. Publishing high-quality articles in regional open peer-reviewed scientific journals is a suitable way to valorize Global South ecology, helping minimize the existing asymmetries.Keywords: ecology, information access, paywall, inequity.Ler artigos científicos é uma atividade fundamental para os pesquisadores, não só para acompanhar os desenvolvimentos em seu campo de ação, mas também para saber sobre os ombros de que gigantes estão de pé. Nesse sentido, Courchamp e Bradshaw (2018) propuseram recentemente uma lista de 100 artigos seminais, considerados de suma importância na ecologia, que constituem uma lista geral de artigos que os novos ecologistas “devem ler”. Os autores falam metaforicamente da ecologia como uma parede de evidência publicada em constante construção. A fim de quantificar o nível de interferência da parede de pagamento no muro da ciência, aproveitamos a oportunidade dada pela lista de 100 artigos seminais e registramos quantos artigos estão disponíveis gratuitamente por meio da entidade editorial. Dos 100 artigos científicos propostos como os fundamentos do muro do conhecimento ecológico, 66 estão por trás do muro de pagamento, com um custo total de US$ 1.560. Esse muro de pagamento exacerba as assimetrias existentes na pesquisa ecológica entre pesquisadores de países desenvolvidos e do sul global. A diversidade na pesquisa, como nos sistemas ecológicos, é uma fonte de robustez. A publicação de artigos de alta qualidade em periódicos regionais de livre acesso e revisados por pares é uma maneira viável de avaliar coletivamente a ecologia do sul global e ajudar a minimizar as assimetrias existentes.Palavras-chave: ecologia, acesso à informação, muro de pagamento, desigualdade

L amino acid transporter structure and molecular bases for the asymmetry of substrate interaction

L-amino acid transporters (LATs) play key roles in human physiology and are implicated in several human pathologies. LATs are asymmetric amino acid exchangers where the low apparent affinity cytoplasmic side controls the exchange of substrates with high apparent affinity on the extracellular side. Here, we report the crystal structures of an LAT, the bacterial alanine-serine-cysteine exchanger (BasC), in a non-occluded inward-facing conformation in both apo and substrate-bound states. We crystallized BasC in complex with a nanobody, which blocks the transporter from the intracellular side, thus unveiling the sidedness of the substrate interaction of BasC. Two conserved residues in human LATs, Tyr 236 and Lys 154, are located in equivalent positions to the Na1 and Na2 sites of sodiumdependent APC superfamily transporters. Functional studies and molecular dynamics (MD) calculations reveal that these residues are key for the asymmetric substrate interaction of BasC and in the homologous human transporter Asc-1

Veinte años de políticas educativas para la educación secundaria: Ampliación del acceso y persistencia de desigualdades

El presente capítulo aborda las políticas sociales y educativas implementadas en el país a partir del año 2000 que tuvieron como foco la ampliación del acceso para cumplir con la obligatoriedad, el incremento de la terminalidad del nivel y la búsqueda de alternativas pedagógicas destinadas a repensar la educación secundaria en el contexto del siglo XXI.Fil: Tiramonti, Guillermina. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Nobile, Mariana. Facultad Latinoamericana de Ciencias Sociales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Montes, Nancy. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Ziegler, Sandra. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Vecino, Luisa. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Piracón, Jaime. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Liticheve, Lucía. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Fridman, Denise. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Nuñez, Pedro. Facultad Latinoamericana de Ciencias Sociales; Argentin

Dietary fatty acids modulate oxidative stress response to air pollution but not to infection

Anthropogenic changes to the environment expose wildlife to many pollutants. Among these, tropospheric ozone is of global concern and a highly potent pro-oxidant. In addition, human activities include several other implications for wildlife, e.g., changed food availability and changed distribution of pathogens in cities. These co-occurring habitat changes may interact, thereby modulating the physiological responses and costs related to anthropogenic change. For instance, many food items associated with humans (e.g., food waste and feeders for wild birds) contain relatively more ω6-than ω3-polyunsaturated fatty acids (PUFAs). Metabolites derived from ω6-PUFAs can enhance inflammation and oxidative stress towards a stimulus, whereas the opposite response is linked to ω3-derived metabolites. Hence, we hypothesized that differential intake of ω6-and ω3-PUFAs modulates the oxidative stress state of birds and thereby affects the responses towards pro-oxidants. To test this, we manipulated dietary ω6:ω3 ratios and ozone levels in a full-factorial experiment using captive zebra finches (Taeniopygia guttata). Additionally, we simulated an infection, thereby also triggering the immune system’s adaptive pro-oxidant release (i.e., oxidative burst), by injecting lipopolysaccharide. Under normal air conditions, the ω3-diet birds had a lower antioxidant ratio (GSH/GSSG ratio) compared to the ω6-diet birds. When exposed to ozone, however, the diet effect disappeared. Instead, ozone exposure overall reduced the total concentration of the key antioxidant glutathione (tGSH). Moreover, the birds on the ω6-rich diet had an overall higher antioxidant capacity (OXY) compared to birds fed a ω3-rich diet. Interestingly, only the immune challenge increased oxidative damage, suggesting the oxidative burst of the immune system overrides the other pro-oxidative processes, including diet. Taken together, our results show that ozone, dietary PUFAs, and infection all affect the redox-system, but in different ways, suggesting that the underlying responses are decoupled despite that they all increase pro-oxidant exposure or generation. Despite lack of apparent cumulative effect in the independent biomarkers, the combined single effects could together reduce overall cellular functioning and efficiency over time in wild birds exposed to pathogens, ozone, and anthropogenic food sources

The Science Case for Multi-Object Spectroscopy on the European ELT

This White Paper presents the scientific motivations for a multi-object spectrograph (MOS) on the European Extremely Large Telescope (E-ELT). The MOS case draws on all fields of contemporary astronomy, from extra-solar planets, to the study of the halo of the Milky Way and its satellites, and from resolved stellar populations in nearby galaxies out to observations of the earliest 'first-light' structures in the partially-reionised Universe. The material presented here results from thorough discussions within the community over the past four years, building on the past competitive studies to agree a common strategy toward realising a MOS capability on the E-ELT. The cases have been distilled to a set of common requirements which will be used to define the MOSAIC instrument, entailing two observational modes ('high multiplex' and 'high definition'). When combined with the unprecedented sensitivity of the E-ELT, MOSAIC will be the world's leading MOS facility. In analysing the requirements we also identify a high-multiplex MOS for the longer-term plans for the E-ELT, with an even greater multiplex (>1000 targets) to enable studies of large-scale structures in the high-redshift Universe. Following the green light for the construction of the E-ELT the MOS community, structured through the MOSAIC consortium, is eager to realise a MOS on the E-ELT as soon as possible. We argue that several of the most compelling cases for ELT science, in highly competitive areas of modern astronomy, demand such a capability. For example, MOS observations in the early stages of E-ELT operations will be essential for follow-up of sources identified by the James Webb Space Telescope (JWST). In particular, multi-object adaptive optics and accurate sky subtraction with fibres have both recently been demonstrated on sky, making fast-track development of MOSAIC feasible.Comment: Significantly expanded and updated version of previous ELT-MOS White Paper, so there is some textual overlap with arXiv:1303.002

TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

ABSTRACT We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA’s Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the Minerva-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of MP = 0.138 ± 0.023 $\rm {M_J}$ (43.9 ± 7.3 $\, M_{\rm \oplus}$), a radius of RP = 0.639 ± 0.013 $\rm {R_J}$ (7.16 ± 0.15 $\, \mathrm{ R}_{\rm \oplus}$), bulk density of $0.65^{+0.12}_{-0.11}$ (cgs), and period $18.38818^{+0.00085}_{-0.00084}$ $\rm {days}$. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M* = 1.390 ± 0.046 $\rm {M_{sun}}$, R* = 1.888 ± 0.033 $\rm {R_{sun}}$, Teff = 6075 ± 90 $\rm {K}$, and vsin i = 11.3 ± 0.5 km s−1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems

Norma de reacción y flexibilidad fenotípica en el canto de Hypsiboas pulchellus : relación con la condición corporal y escalamiento de sus atributos

Tribunal : Dr. Carlos A. Navas, Dr. Pablo A. Marquet, Dra. Ana C. Silva, Dr. Álvaro Soutullo

Plasticidad en el canto de los anuros : el efecto de la estructura del hábitat

Tribunal: Dr. Enrique P. Lessa, Dr. Daniel E. Naya, Dr. Marcelo LoureiroOrientadores: Dr. Matías Arim, Dr. Peter M. Narin

Molybdenum and rhenium carbonyl complexes containing thiolato ligands

The reaction of fac-[M(OTf)(CO)3(N–N)](M = Mn, Re; N–N = 2,2′-bipyridine, 1,10-phenanthroline) complexes with in situ generated LiSEt afforded immediately, in THF at low temperature, the corresponding mononuclear terminal thiolato complexes fac-[M(SEt)(CO)3(N–N)](1-2a,b). Using an analogous synthetic strategy, tungsten and molybdenum (II) alkyl- and arylthiolatos of formula cis-[M(SR)(η3-allyl)(CO)2(N–N)] (3-6a,b) have been obtained. Preliminary reactions of the more reactive molybdenum thiolato complexes towards dimethylacetylenedicarboxylate led to Z-alkenyl products (7a,b), resulting from the insertion of the organic unsaturated electrophile into the Mo–S bond. For each new type of compound, one representative has been characterized in the solid state by X-ray diffraction.Financial support from Ministerio de Economía y Competitividad/FEDER (grant CTQ2015-70231-P), Ministerio de Ciencia, Innovacion y Universidades (grant PGC2018-097366-B-100), and Principado de Asturias (grant GRUPIN14-103, and Severo Ochoa predoctoral fellowship to S. F.) is gratefully acknowledged. S. Z. participated in this work during her stay at Universidad de Oviedo as an Erasmus exchange student from University of Heidelberg.Peer reviewe