An insight into the patterns and controls of the structure of South America n Chaco woodlands Ferraina, Antonella; Baldi, Germán; Abelleyra, Diego; Grosfeld, Javier Edgardo; Verón, Santiago Ramón Logging, grazing, wood extraction, and anthropogenic fires are pervasive throughout the subtropical dry vegetation of South America leading to changes in woodlands structure and ultimately its degradation. The Chac ohaco biome encompasses the second-largest forest in South America and has a long history of intensive use. We sought to characterize the structure and heterogeneity of its woodlands across biogeographic subunits and climatic gradients, and evaluate structure controls. We quantified canopy height, cover, vertical complexity, vegetation amount above 3 m and total vegetation amount over 58 woodlands within the Argentinean Chaco by means of terrestrial laser scanner. We assessed the relationship between three groups near the maximum, average and minimum values of each structural variable and precipitation, temperature and temperature of the coldest month using quantile regressions. We found large variability in structural attributes within each biogeographical subunit, showing woodland areas with similar structure across broad gradients of climate. This suggests a considerable impact of current and past land use in shaping woodland structures across the Chaco. Overall, structural variables were positively associated with precipitation and temperature, albeit more strongly to the former, except for canopy height, which showed a strong association with mean temperature of the coldest month. We hypothesize that land-use impact on woodland structure decreases with increasing precipitation, as the lack of water may limit the recovery of vegetation structure. Our results contribute to a better understanding of variation in key structural variables of Chaco woodlands in relation to climate and land use.

Bull sperm selection by attachment to hyaluronic acid semi-interpenetrated hydrogels Liaudat, Ana Cecilia; Blois, Damián Andrés; Capella, Virginia; Morilla, Gricelda Dolinda; Rivero, Rebeca Edith; Barbero, César Alfredo; Rodriguez, Nancy; Rivarola, Claudia Rosana; Bosch, Pablo We report the development of a hydrogel-based approach to select bull spermatozoa, a crucial step for successful assisted reproductive techniques (ARTs). Hyaluronic acid (HA) semi-interpenetrated N-isopropylacrylamide (PNIPAM) co-20% N-Tris (hydroxymethyl) methyl acrylamide (HMA) hydrogels were synthetized on glass surfaces and cultured in presence of frozen-thawed bull spermatozoa. A fraction of motile bull spermatozoa population strongly attached to hydrogels and was partially released by treatment with hyaluronidase. Fifty-nine (59 ± 7.24) per cent of sperm cells attached to PNIPAM-HMA-HA hydrogels and 31.16 ± 4.81% of them were released upon treatment with medium containing hyaluronidase. This attached-released sperm fraction has acceptable characteristics of progressive motility (50.0 ± 5.0%), vigour (4), high viability (58.7 ± 11.7%) and low percentage of acrosome reacted spermatozoa (23.36 ± 4.1%). Our findings indicate that PNIPAM-HMA-HA hydrogels are non-toxic and allow the selection of high-quality sperm cells for ART.

Infection with Spiroplasma kunkelii on temperate and tropical x temperate maize in Argentina and development of a tool to evaluate germplasm Barontini, Javier Miguel; Peña Malavera, Andrea Natalia; Ferrer, Mariana; Torrico Ramallo, Ada Karina; Maurino, Maria Fernanda; de la Paz Giménez Pecci, María Corn stunt disease is a disease that extends from the southern United States to Argentina and is one of the most important diseases in warm subtropical areas of the continent, periodically causing yield reductions in maize. The aims of this study were to develop a severity scale, estimate the effect of corn stunt caused by Spiroplasma kunkelii in maize hybrids, and identify attributes related to yield loss that would be useful to evaluate germplasms. Under artificial inoculation conditions with infective and non-infective insects, symptoms were grouped to develop and validate a scale and a severity index. Disease severity, moment of appearance of the characteristic symptom, pathogen concentration, and effect on yield were correlated for eight temperate and temperate x tropical commercial and precommercial hybrid maize germplasms. We developed and validated a 7-score severity scale. The characteristic symptom of S. kunkelii infection occurs earlier in the temperate germplasm than in the tropical x temperate germplasm. The performance of two of the four temperate germplasms was remarkable compared to the hybrids. Severity and pathogen concentration were correlated with each other, and both correlated with yield and with yield reduction. The moment of appearance of the characteristic disease symptom did not correlate with the other attributes. The severity index and the pathogen concentration may be useful to evaluate germplasm.

Local enhancement of hydrogen production by the hydrolysis of Mg17Al12 with Mg “model” material Al Bacha, S.; Farias, Eliana Desiree; Garrigue, Patrick; Zakhour, Mirvat; Nakhl, Michel; Bobet, Jean Louis; Zigah, Dodzi The effect of galvanic coupling on the corrosion behavior of Mg and Mg17Al12 in Mg-Al alloys was studied by Scanning ElectroChemical Microscopy (SECM). The effect of galvanic coupling between Mg and Mg17Al12 was investigated using a “model” Mg+Mg17Al12 material with a controlled microstructure to evaluate the hydrogen evolution at a micrometric scale. SECM maps revealed that galvanic coupling between Mg and Mg17Al12 accelerates the corrosion rate (formation of a thicker passive layer) of both components. Mg17Al12 acts controversially to a conventional cathode in galvanic system since hydrogen production by its hydrolysis reaction was found to increase due to the electron transfer with the anode (Mg).

Antifouling Diterpenoids from the Sponge Dendrilla antarctica Prieto, Iván Maximiliano; Paola, Analia Cristina; Perez, Miriam Cristina; García, Mónica; Blustein, Guillermo; Schejter, Laura; Palermo, Jorge Alejandro Two nor-diterpenes, 9,11-dihydrogracilin A (1) and the previously unreported 9,11-dihydrogracillinone A (2), were isolated from the sponge Dendrilla antarctica. The sponge was collected by trawling at a depth of 49 m, from the research vessel Puerto Deseado, near the coast of Tierra del Fuego, farther north than the reported habitat for this species. Since these compounds were particularly abundant and the sponge was free from epibionts, both 1 and 2 were included in soluble-matrix paints and tested for antifouling activity in the ocean. The results obtained from these experiments clearly indicated a potent antifouling activity for both compounds against a variety of colonizing organisms, and established a probable role as natural antifoulants for these abundant secondary metabolites and other structurally related compounds previously isolated from Dendrilla spp.

Synthetic silica nano-organelles for regulation of cascade reactions in multi-compartmentalized systems Jiang, Shuai; Da Silva, Lucas Caire; Ivanov, Tsvetomir; Mottola, Milagro; Landfester, Katharina In eukaryotic cells, enzymes are compartmentalized into specific organelles so that different reactions and processes can be performed efficiently and with a high degree of control. In this work, we show that these features can be artificially emulated in robust synthetic organelles constructed using an enzyme co-compartmentalization strategy. We describe an in situ encapsulation approach that allows enzymes to be loaded into silica nanoreactors in well-defined compositions. The nanoreactors can be combined into integrated systems to produce a desired reaction outcome. We used the selective enzyme co-compartmentalization and nanoreactor integration to regulate competitive cascade reactions and to modulate the kinetics of sequential reactions involving multiple nanoreactors. Furthermore, we show that the nanoreactors can be efficiently loaded into giant polymer vesicles, resulting in multi-compartmentalized microreactors.

Alfabetización digital como ética preventiva: Educación metacognitiva para el contexto mediático post COVID-19; Digital literacy as preventive ethics: Metacognitive education for the post-COVID-19 media context Suárez, Ernesto Joaquín; Gonzalez Galli, Leonardo Martin Durante la pandemia de COVID-19 y la infodemia que la acompañó, la alfabetización digital demostró ser un enfoque preventivo con la posibilidad de ofrecer guías a futuro para contemplar las influencias negativas de los medios digitales en el contexto post-pandemia. Ahora bien, este énfasis en las potencialidades de la alfabetización digital requiere, al mismo tiempo, una revisión de sus supuestos tradicionales, con el fin de optimizar sus características en el contexto venidero. Uno de los aspectos centrales de esta revisión se relaciona con la inclusión de la injerencia que poseen los sesgos cognitivos en la utilización de los medios digitales contemporáneos, en los cuales prolifera la desinformación y la información errónea. Un claro ejemplo de ello durante la pandemia ha sido la difusión de múltiples teorías conspirativas. Partiendo de aquí, el objetivo de este artículo será analizar el posible aporte de la metacognición, cuando es comprendida como un componente fundamental de la alfabetización digital.; During the COVID-19 pandemic and the infodemic that accompanied it, digital literacy proved to be a preventive approach with the possibility of offering future guidance to contemplate the negative influences of digital media in the postpandemic context. However, this emphasis on the potentialities of digital literacy requires, at the same time, a review of its traditional assumptions, in order to optimize its characteristics in the future context. One of the central aspects of this review is related to the inclusion of the interference that cognitive biases have in the use of contemporary digital media, in which misinformation and misinformation proliferate. A clear example of this during the pandemic has been the spread of multiple conspiracy theories. Starting from here, the objective of this article will be to analyze the possible contribution of metacognition, when it is understood as a fundamental component of digital literacy.

Factores que diferencian el consumo frecuente y esporádico de marihuana en estudiantes universitarios; Factors differentiating frequent and sporadic marijuana use in college students Pilatti, Angelina; Rivarola Montejano, Gabriela Belen; Nillus, Macarena; Fernandez, Macarena Soledad; Pautassi, Ricardo Marcos Aunque el consumo de marihuana es altamente prevalente entre universitarios de Argentina, poco se sabe respecto a los factores que permiten distinguir a los consumidores frecuentes de marihuana de quienes consumen esporádicamente. Por esta razón, en el presente trabajo se indagó sobre las posibles variaciones en los contextos de consumo, motivos de consumo, normas percibidas y estrategias conductuales de protección entre universitarios con consumo frecuente o esporádico de marihuana, y se analizó la utilidad de este conjunto de variables para distinguir entre estos los tipos de consumidores mencionados. Para ello, se contó con una muestra de 1083 estudiantes universitarios argentinos que completó una encuesta en línea sobre el consumo de sustancias. En particular, este trabajo se realizó con la submuestra que reportó consumir marihuana en los últimos 30 días (n = 158; 51.3 % mujeres). Dicha encuesta interrogaba sobre el consumo de marihuana y las consecuencias negativas asociadas, así como por motivos de consumo, normas sociales percibidas y estrategias conductuales de protección. Como resultado, los consumidores frecuentes presentaron mayor cantidad de consecuencias negativas (M = 4.92) que los consumidores esporádicos (M = 1.82; p ≤ .05), y se halló un perfil distintivo en un conjunto de variables. A nivel multivariado, los motivos de animación (or = 1.230; p ≤ .05), las estrategias conductuales de protección (or = .941; p ≤ .05), el consumo en solitario (or = 2.024; p ≤ .05) y el consumo en fiestas universitarias (or = 2.669; p ≤ .05) discriminaron significativamente entre ambas clases de consumidores. En general, los hallazgos revelaron subpoblaciones heterogéneas de consumidores de marihuana que difieren no solo en el consumo y sus consecuencias, sino también en los contextos de consumo y en un conjunto de variables relevantes. Estas subpoblaciones distintivas requieren de intervenciones diferentes y específicas.; Although marijuana use is highly prevalent among university students in Argentina, little is known about the factors that distinguish frequent marijuana users from sporadic users. For this reason, the present study investigated the possible variations in the contexts of consumption, motives for consumption, perceived norms, and protective behavioral strategies among university students with frequent or sporadic marijuana use, and analyzed the usefulness of this set of variables to distinguish between these two types of users. For this purpose, a sample of 1083 Argentine university students completed an online survey on substance use. In particular, this work was conducted with the subsample that reported using marijuana in the last 30 days (n = 158; 51.3 % female). The survey asked about marijuana use and associated negative consequences, as well as motives for use, perceived social norms, and protective behavioral strategies. As a result, frequent users had a higher number of negative consequences (M = 4.92) than sporadic users (M = 1.82; p ≤ .05), and a distinctive profile was found on a set of variables. At the multivariate level, cheerleading motives (OR = 1.230; p ≤ .05), protective behavioral strategies (OR = .941; p ≤ .05), solo use (OR = 2.024; p ≤ .05), and college party use (OR = 2.669; p ≤ .05) discriminated significantly between the two classes of users. Overall, the findings revealed heterogeneous subpopulations of marijuana users that differ not only in use and its consequences, but also in contexts of use and in a set of relevant variables. These distinct subpopulations require different and specific interventions.

Hyperbolicity of the Karcher mean Ghiglioni, Eduardo Mario; Lim, Yongdo The main concern of this paper is the Karcher mean of linearly independent triples (A,B,C) on the hyperbolic manifold of 2×2 positive definite matrices of determinant 1. We show that the Karcher mean is of the form Λ(A,B,C)=xA+y(B+C),0

De la fractura metabólica a la acumulación por desposesión: minería del litio, imperialismo ecológico y despojo hídrico en el noroeste argentino; From metabolic rift to accumulation by dispossession: lithium mining, ecological imperialism and hydric looting in the argentinean northwest; Da fratura metabólica à acumulação por expropiação: mineração de lítio, imperialismo ecológico e desapropriação de água no noroeste da argentina; De la fracture métabolique à l'accumulation par dépossession: exploitation de lithium, impérialisme écologique et gaspillage de l'eau dans le nord-ouest de l'argentine; Dalla frattura metabolica all'accumulo da deposessione: minerario di litio, imperialismo ecologico e smaltimento dell'acqua nel nordovest dell'argentina Gómez Lende, Sebastián Con epicentro en los salares del llamado “Triángulo del Litio”, el litio es una materia prima clave para el capitalismo contemporáneo. Esencial para producir las baterías recargables necesarias para reestructurar la industria automotriz hacia los vehículos eléctricos y efectuar la transición energética desde los hidrocarburos hacia las fuentes renovables, la extracción de litio en salmueras es una actividad fuertemente hidro-intensiva llevada a cabo en zonas extremadamente áridas. Valiéndose de datos oficiales, bibliografía académica e informes corporativos y periodísticos, este artículo caracteriza el boom del litio en el noroeste argentino (provincias de Jujuy y Catamarca) y estudia el consumo hídrico de la actividad y los conflictos entre empresas y comunidades locales por el uso del agua. Los resultados muestran que la explotación de este mineral opera como un mecanismo de acumulación por desposesión e imperialismo ecológico que despoja a grupos sociales (aborígenes, sobre todo) del agua básica para la subsistencia.; With its epicentre in the so-called Lithium Triangle’s salars, lithium is a key raw material for the contemporary capitalism. Essential to the production of rechargeable batteries -which are necessary for both restructuring automotive industry towards the electric vehicles and performing the energy transition from hydrocarbons to renewable sources-, the lithium extraction from brines is a highly hydro-intensive activity carried out in extremely arid regions. Using official data, scholar literature and corporate and journalistic reports, this paper characterizes the lithium boom in the Argentinean Northwest (provinces of Jujuy and Catamarca) and studies both the hydric consumption of such activity and the conflicts between mining companies and local communities regarding the access to water. The findings show that lithium mining operates as a mechanism of accumulation by dispossession and ecological imperialism that snatches social groups (aborigines, specially) from the water they need to survive.; Com seu epicentro nos salares do chamado Triângulo de Lítio, o lítio é uma matéria-prima fundamental para o capitalismo contemporâneo. Essencial para a produção de baterias recarregáveis -necessárias tanto para reestruturar a indústria automotiva rumo aos veículos elétricos quanto para realizar a transição energética de hidrocarbonetos para fontes renováveis-, a extração de lítio de salmouras é uma atividade altamente hidrointensiva realizada em regiões extremamente áridas. Utilizando dados oficiais, literatura acadêmica e relatórios corporativos e jornalísticos, este trabalho caracteriza o boom do lítio no noroeste argentino (províncias de Jujuy e Catamarca) e estuda tanto o consumo hídrico dessa atividade quanto os conflitos entre mineradoras e comunidades locais sobre o acesso à água. Os resultados mostram que a mineração de lítio funciona como um mecanismo de acumulação por expropriação e imperialismo ecológico que arranca grupos sociais (principalmente aborígenes) da água de que precisam para sobreviver.; Avec son épicentre dans les salars du soi-disant triangle du lithium, le lithium est une matière première essentielle pour le capitalisme contemporain. Indispensable à la production de batteries rechargeables -qui sont nécessaires à la fois pour restructurer l’industrie automobile vers le véhicule électrique et réaliser la transition énergétique des hydrocarbures vers les sources renouvelables-, l’extraction du lithium à partir de saumures est une activité hautement hydro-intensive exercée dans des régions extrêmement arides. À l’aide de données officielles, de la littérature scientifique et de rapports d’entreprise et journalistiques, cet article caractérise le boom du lithium dans le nord-ouest argentin (provinces de Jujuy et Catamarca) et étudie la consommation d’eau de l’activité et les conflits entre entreprises et communautés locales sur l’utilisation de l’eau. Les résultats montrent que l’extraction du lithium fonctionne comme un mécanisme d’accumulation par dépossession et impérialisme écologique qui arrache les groupes sociaux d’eau de base pour leur subsistance.; Con il suo epicentro nei salari del cosiddetto Triangolo del Litio, il litio è una materia prima fondamentale per il capitalismo contemporaneo. Essenziale per la produzione di batterie ricaricabili -che sono necessarie sia per ristrutturare l'industria automobilistica verso i veicoli elettrici sia per effettuare la transizione energetica dagli idrocarburi alle fonti rinnovabili-, l'estrazione del litio dalle salamoie è un'attività altamente idrointensiva svolta in regioni estremamente aride. Utilizzando dati ufficiali, letteratura accademica e rapporti aziendali e giornalistici, questo documento caratterizza il boom del litio nel nord-ovest argentino (province di Jujuy e Catamarca) e studia sia il consumo idrico di tale attività sia i conflitti tra le società minerarie e le comunità locali per quanto riguarda l'accesso all'acqua. I risultati mostrano che l'estrazione del litio funziona come un meccanismo di accumulo per espropriazione e imperialismo ecologico che sottrae ai gruppi sociali (gli aborigeni, specialmente) l'acqua di cui hanno bisogno per sopravvivere.

An action-concept processing advantage in a patient with a double motor cortex Miranda, Magdalena; Gonzalez Campo, Cecilia; Birba, Agustina; Neely, Alejandra; Toro Hernandez, Felipe; Faure, Evelyng; Rojas Costa, Gonzalo; Ibañez, Agustin Mariano; García, Adolfo Martín Patients with atrophy in motor brain regions exhibit selective deficits in processing action-related meanings, suggesting a link between movement conceptualization and the amount of regional tissue. Here we examine such a relation in a unique opposite model: a rare patient with a double cortex (due to subcortical band heterotopia) in primary/supplementary motor regions, and no double cortex in multimodal semantic regions. We measured behavioral performance in action- and object-concept processing as well and resting-state functional connectivity. Both dimensions involved comparisons with healthy controls. Results revealed preserved accuracy in action and object categories for the patient. However, unlike controls, the patient exhibited faster performance for action than object concepts, a difference that was uninfluenced by general cognitive abilities. Moreover, this pattern was accompanied by heightened functional connectivity between the bilateral primary motor cortices. This suggests that a functionally active double motor cortex may entail action-processing advantages. Our findings offer new constraints for models of action semantics and motor-region function at large.

Desigualdades socioespaciales de la mortalidad por COVID-19 en tres olas de propagación: un análisis intraurbano en Argentina; Socio-spatial inequalities in COVID-19 mortality in the three waves: an intraurban analysis in Argentina; Desigualdades socioespaciais da mortalidade por COVID-19 em três ondas de propagação: una análise intraurbana na Argentina Leveau, Carlos Marcelo; Soares Bastos, Leonardo Nuestro propósito fue investigar las diferencias de las desigualdades socioespaciales de la mortalidad por COVID-19 entre tres olas de propagación del virus en la Ciudad Autónoma de Buenos Aires (CABA), Argentina. Los datos de mortalidad por COVID-19 se obtuvieron de la base de datos de casos de COVID-19, informados por el gobierno de la CABA, desde el 7 de marzo de 2020 hasta el 30 de septiembre de 2021. Se determinaron tres olas: la primera ola, entre los meses de marzo y diciembre de 2020, la segunda ola, entre diciembre y marzo de 2021, y la tercera ola, entre marzo y septiembre de 2021. En cada ola se calcularon regresiones multivariadas para analizar la asociación entre el riesgo de mortalidad por COVID-19, en dos grupos etarios (0-59 años y 60 o más años), y el porcentaje de hogares con necesidades básicas insatisfechas, como indicador del nivel de pobreza de los barrios, y la densidad poblacional. Durante la primera ola y en ambos grupos etarios, los barrios del tercil con mayores porcentajes de hogares con necesidades básicas insatisfechas tuvieron un riesgo mayor de mortalidad por COVID-19, en comparación a los barrios del tercil con menores porcentajes de hogares con necesidades básicas insatisfechas. Estas desigualdades desaparecieron durante la segunda ola en ambos grupos etarios, mientras que en la tercera ola pareció emerger un patrón geográfico similar al de la primera ola. Es posible que mayores niveles de inmunidad en barrios con niveles altos de pobreza pudieran explicar parcialmente la ausencia de desigualdades socioespaciales durante la segunda ola, mientras que la irrupción de las variantes gamma y lambda podría explicar parcialmente el retorno a las desigualdades observadas en la primera ola.; The study aimed to analyze the socio-spatial differences in COVID-19 mortality in the pandemic’s three waves in the city of Buenos Aires, Argentina. COVID-19 mortality data were obtained from the COVID-19 Database and reported by the Buenos Aires Autonomous Government from March 7, 2020, to September 30, 2021. Three waves were identified: the first from March to December 2020, the second from December 2020 to March 2021, and the third from March to September 2021. Multivariate regressions were calculated for each wave to analyze the association between risk of COVID-19 mortality in two age groups (0-59 years and 60 years or older) and the percentage of households with unmet basic needs as indicator of neighborhood poverty level, and population density. During the first wave and in both age groups, the neighborhood in the tertile with the highest percentages of households with unmet basic needs showed higher risk of COVID-19 mortality when compared to neighborhoods in the tertile with the lowest percentages of households with unmet basic needs. These inequalities disappeared in the second wave in both age groups, while the third wave saw a similar geographic pattern to the first wave. Higher levels of immunity in neighborhoods with high poverty levels might partially explain the absence of socio-spatial inequalities in the second wave, while the emergence of the gamma and lambda variants could partially explain the return to inequalities observed in the first wave.; A proposta era investigar as diferenças nas desigualdades socioespaciais da mortalidade por COVID-19 entre três ondas de propagação do vírus na Cidade Autônoma de Buenos Aires, Argentina. Os dados de mortalidade por COVID-19 foram obtidos a partir da base de dados dos casos de COVID-19 informados pelo governo da Cidade Autônoma de Buenos Aires, do dia 7 de março de 2020, até 30 de setembro de 2021. Foram identificadas três ondas: a primeira, entre os meses de março e dezembro de 2020, a segunda, entre dezembro e março de 2021, e a terceira, entre março e setembro de 2021. Para cada uma delas, foram calculadas regressões multivariadas, visando analisar a associação entre o risco de mortalidade por COVID-19 em dois grupos etários (0-59 anos e 60 anos ou mais), e o percentual de domicílios com necessidades básicas não atendidas, como indicador do nível de pobreza dos bairros, e a densidade populacional. Durante a primeira onda e em ambos grupos etários, os bairros do tercil com maiores percentuais de domicílios com necessidades básicas não atendidas apresentaram um risco maior de mortalidade por COVID-19 na comparação com os bairros do tercil com menores taxas de domicílios com necessidades básicas não atendidas. Estas desigualdades desapareceram durante a segunda onda nos dois grupos etários, ao passo que, na terceira onda parece ter emergido um padrão geográfico similar ao da primeira onda. Maiores níveis de imunidade em bairros com altas taxas de pobreza poderiam explicar parcialmente a ausência de desigualdades socioespaciais durante a segunda onda, sendo que a irrupção das variantes gama e lambda poderia explicar parcialmente a volta para as desigualdades observadas na primeira onda.

COVID-19’s impact on international trade Coquidé, Célestin; Lages, José; Ermann, Leonardo; Shepelyansky, Dima L. We analyze how the COVID-19 pandemic affected the trade of products between countries. With this aim, using the United Nations Comtrade database, we perform a Google matrix analysis of the multiproduct World Trade Network (WTN) for the years 2018–2020, comprising the emergence of the COVID-19 as a global pandemic. The applied algorithms—PageRank, CheiRank and the reduced Google matrix—take into account the multiplicity of the WTN links, providing new insights into international trade compared to the usual import–export analysis. These complex networks analysis algorithms establish new rankings and trade balances of countries and products considering all countries on equal grounds, independent of their wealth, and every product on the basis of its relative exchanged volumes. In comparison with the pre-COVID-19 period, significant changes in these metrics occurred for the year 2020, highlighting a major rewiring of the international trade f lows induced by the COVID-19 pandemic crisis. We define a new PageRank–CheiRank product trade balance, either export or import-oriented, which is significantly perturbed by the pandemic.

UAV photogrammetry and GIS in visibility/invisibility interpretations of extended archaeological contexts. The case of Tacuil in the Calchaquí area (Argentina) Orsini, Carolina; Benozzi, Eliza; Williams, Veronica Isabel; Rossi, Paolo; Mancini, Francesco The scope and scientific purpose of this paper focuses on multiscale (aerial and terrestrial) photogrammetry as a support to investigations and interpretations in a multi-component archaeological site located in the Argentinian Cordillera (Calchaquí, Salta), known as Tacuil. Due to its scarce accessibility, as well as long-term problems associated with the interpretation of the visibility of this type of settlement, the use of aerial surveying was combined with the reconstruction of structures and complex soil morphologies by resorting to modern photogrammetric approaches (3D models and orthophotos). This dataset was complemented by a terrestrial survey to obtain extremely high resolution and detailed representations of archaeological features that were integrated in a GIS database. The outcome of photogrammetric surveying was fundamental in supporting the debate on the functionality of the site and his integration in a complex, socially constructed, ancient landscape. Finally, the present paper introduces the first complete map of Tacuil.

Clean recovery of phenolic compounds, pyro-gasification thermokinetics, and bioenergy potential of spent agro-industrial bio-wastes Fernandez Brizuela, Anabel Alejandra; Sette, Paula Andrea; Echegaray, Marcelo Eduardo; Soria, Jose Miguel; Salvatori, Daniela Marisol; Mazza, German Delfor; Rodriguez, Rosa Ana The sequential process of polyphenol extraction from agro-industrial bio-wastes and pyrolysis/gasification of the residual solid fraction (RSF) constitutes an upgrading of the bio-waste to fuel and chemicals processes in the frame of the biorefinery conception. This process can be conducted based on sustainability concepts for bio-waste management, following the premises of the circular economy and the objective of reaching almost zero waste conditions. After the extraction process of apple pomace, grape marc, and grape stalk bio-wastes, three extracts rich in sugar, organic acids, and bioactive compounds were obtained. The polyphenol content was higher in extracts from grape wastes (4990 ± 55 mg gallic acid/100 g in grape marc and 6997 ± 70 mg gallic acid/100 g in grape stalk). However, the apple pomace extraction process was more efficient, since the RSF did not exhibit residual antioxidant capacity. The pyro-gasification kinetics of the RSF was investigated. The results indicated that the Flynn–Wall–Ozawa method presented the best R2, RSME, and SSE values. The Coats–Redfern method was applied to determine the reaction mechanism. For both pyrolysis and gasification processes, it was found that the first-order reaction and three-dimensional diffusion (Ginstling–Brounstein) models properly described the second and third process stages, respectively. The resulting values of the thermodynamic parameters, ΔG, ΔH, and ΔS, were 148.55 kJ/mol, 73.66 kJ/mol, and − 0.11 kJ/K mol, respectively, for pyrolysis and 110.91 kJ/mol, 105.44 kJ/mol, and − 0.01 kJ/K mol for gasification, respectively. According to bioenergy indicators, the RSF from the three bio-wastes had acceptable characteristics as a biofuel feedstock.

Generation of second-order electrochemical data for interference-free calibration of gallic acid in red wines Montemerlo, Antonella Evelin; Azcarate, Silvana Mariela; Camiña, José Manuel; Messina, Germán Alejandro Wine consists of a solution of ethanol in water, which also contains a variety of organic compounds, such as organic acids, amino acids, sugars, volatile compounds and polyphenols in different concentrations. In particular, the interest in the latter is continuously growing due to its bioactive nature and its close relationship with the final qualities of the resulting product. Specifically, gallic acid is one of the most widely used phenolic compounds as a marker for the characterization of wine products.The use of sulfur dioxide is a common practice in oenology that is currently considered essential for the correct finish of wines. However, there is a growing concern about the reduction of its levels in the final product, which makes it necessary to search for complementary agents. Among the possible alternatives is ascorbic acid or vitamin C. In recent years, its use as an additive for winemaking has been reported due to its antioxidant properties, its reducing nature and because it is a healthy compound. It is important to note that ascorbic acid will never replace the use of sulfites, but it can be an excellent complement to it.The rise of multidirectional calibration enabled the quantification of numerous analytes in complex samples without interference, even in the presence of components not modeled in the calibration, commonly referred to as a second-order advantage. However, classical chemometric methodologies assume that the data comply with the property of bilinearity, which is sometimes not possible to achieve with all instrumental methods. Among them, electrochemistry is capable of providing information with high potential to be used in the development of novel second-order calibration methodologies, although they may not meet the aforementioned conditions.This work raises the possibility of developing a simple and versatile methodology for the interference-free quantification of gallic acid in the presence of ascorbic acid, based on chemometric modeling of electrochemical data. Second-order data were generated by cyclic voltammetry (CV) at different scanning speeds and various modeling strategies were implemented to treat the data obtained.The quantification of gallic acid in the presence of ascorbic acid was possible using a model based on the resolution of multivariate curves-alternating least squares (MCR-ALS). It was found that the optimal number of estimated components for calibration is equal to one. While the analytical figures of merit found, REP% 9.4, LOD 6.094x10-5 mol L-1, show the possibility of using this methodology for the quantification of gallic acid in complex samples.The studies carried out open the doors for wine quality analysis through new and innovative methodologies based on the potential of electrochemical data, combined with chemometric techniques, which make it possible to obtain results in a simple, fast and reliable way for quality control in the wine industry.

Arqueología de la Segunda Guerra Mundial en Sudamérica: el asentamiento Nazi de Teyú Cuaré Schavelzon Chavin, Daniel Gaston; Igareta, Ana Teresa La naturaleza intrínseca de los conflictos bélicos hace que sus efectos se extiendan hacia territorios más extensos que aquellos directamente involucrados en el conflicto. Así, la Segunda Guerra Mundial impactó a nivel material, social y político en toda Europa y otros países del mundo. En Argentina han sido estudiados los fenómenos económicos, políticos y sociales derivados de lo allí ocurrido pero hasta hoy no se tenían noticias de la existencia de instalaciones arquitectónicas cuya presencia pudiera entenderse como la adaptación local de un proyecto originado en Alemania.Los trabajos realizados en el sitio Teyú Cuaré (San Ignacio, Misiones) permitieron proponer que las estructuras líticas allí presentes fueron edificadas hacia mediados de la década de 1940 utilizando recursos y materiales locales pero siguiendo la lógica impuesta por un diseño alemán. El estudio de sus características puso en evidencia singularidades en el contexto de la región, así como también su carácter de desarrollo arquitectónico novedoso con una función diferente a la de vivienda.El registro mueble asociado reafirmó la relación propuesta entre el lugar y recursos extranjeros al incluir una variedad de elementos poco frecuentes en sitios de mediados del siglo XX en nuestro país y cuyo origen puede ser rastreado al territorio entonces controlado por el Tercer Reich.

Detección por SERS del pesticida piraclostrobina en bajas concentraciones Dominguez, Alfredo Nicolás; Alvarez, Rosa Maria Susana La piraclostrobina es un fungicida sistémico local de la familia de las estrobilurinas, recomendado para el control de la “mancha negra” en plantaciones de citrus. Como todo pesticida, su concentración en los productos para consumo humano está sujeta a un estricto control, de forma tal que no supere el nivel máximo de residuos permitido (2 mg/Kg según la FAO 1). Entre los diferentes métodos de análisis de detección, la espectroscopía Raman intensificada en superficie (SERS) resulta particularmente apropiada para este fin, dado que permite el estudio de analitos en muy bajas concentraciones. Su sensibilidad se basa en la intensificación, en varios órdenes de magnitud, que experimenta el espectro vibracional de moléculas adsorbidas sobre una superficie metálica nanoestructurada como consecuencia de la resonancia plasmónica inducida por una fuente de excitación adecuada.El presente trabajo se enfoca en la fabricación de un sustrato constituido por nanopartículas de plata (NPsAg) adecuado para implementar la técnica SERS como método rápido y confiable para la detección de piraclostrobina residual en la cáscara de limón.Estudios previos llevados a cabo por nuestro grupo empleando suspensiones coloidales de NPsAg sintetizadas por reducción química a partir de AgNO3 y NH2OH.HCl 2, fueron promisorios para la detección del fungicida en concentraciones diluidas. Sin embargo, fue necesario que el sistema NPsAg + pesticida se incubara por tres días como mínimo para asegurar la obtención de señales espectrales significativas 3. Con el propósito de acelerar los tiempos de análisis, se exploraron otras alternativas para la construcción de sustratos SERS más eficientes, obteniéndose mejores resultados cuando la suspensión de NPsAg se siembra sobre vidrio y se lleva a sequedad de manera de lograr el efecto “coffee ring” 4 sobre el cual se depositan luego 5 μl de la solución de piraclostrobina en CH2Cl2, en el rango de concentraciones 10-3 - 10-5 M.Empleando un microscopio Raman (Thermo Fisher Scientific) equipado con un láser de 532 nm y usando la mínima potencia (1 mW) para evitar efectos térmicos, se registraron los espectros mediante mapeos superficiales sobre un sector del borde de la mancha (ver Fig.1).La presencia del fungicida se basó en la observación de la banda ubicada a 936 cm-1 que corresponde a la deformación en el plano del anillo pirazol 5 y su intensidad se relacionó linealmente con la concentración de piraclostrobina. Con este método, la detección de la piraclostrobina es casi inmediata al momento de la siembra sobre las NPsAg. Además, se observó que el efecto “coffee ring” permite que la reproducibilidad de las lecturas realizadas en el borde externo de la mancha esté en el orden aceptable (RSD≈20%) debido a un arreglo uniforme de las NPsAg, mientras que en la zona interna de la región muestreada las intensidades de la banda marcadora son más aleatorias como consecuencia de una distribución menos pareja del sustrato.Los presentes resultados sugieren que el empleo de una superficie que permita una deposición más homogénea de las NPsAg impactaría en una mayor confiabilidad del método de detección del analito, razón por la cual se propone continuar con estos estudios explorando el uso de soportes hidrofóbicos 6.

El tigre de Cortés: bordes, desplazamientos y escritura en el archivo cortesiano Añon, Valeria En 2021 conmemoramos el V Centenario de la caída de Tenochtitlan. El archivo que da cuenta de este evento modélico y polémico tiene en la figura y en la escritura de Hernán Cortés un actor central, tan anatematizado como elogiado. La efeméride permite revisar,desde una perspectiva literaria, los modos en que el archivo cortesiano ha sido leído y los vínculos que este establece con las cartas cortesianas. Este trabajo analiza algunas cartas reservadas en articulación con las Cartas de relación para dar cuenta de las tensiones entre archivo y corpus; figura de autor y escritura; relato, silencio y secreto.

Explotación y consumo de animales exóticos en el sector III del sitio de Punta de la Peña 9 (Antofagasta de la Sierra, Catamarca, Argentina) Navarrete Belda, Vanessa; Urquiza, Silvana Valeria; Cohen, Lorena M. La introducción y gestión de especies animales domésticas exóticas en desiertos de altura conforma un escenario particular para el estudio de múltiples formas de gestión y explotación animal. El estudio de las prácticas económicas en asentamientos agropastoriles de Antofagasta de la Sierra ha puesto de manifiesto la complejidad en las estrategias y prácticas ganaderas desarrolladas durante los primeros contactos coloniales. En este trabajo se presentan los resultados del análisis zooarqueológico del sitio de Punta de la Peña 9 (PP9), ubicado en el sector intermedio de Antofagasta de la Sierra, a 2600 msnm. Se han analizado los restos de fauna procedentes de la Estructura 4 del Sector III con el objetivo de caracterizar los cambios en la explotación y consumo animal durante los primeros momentos de la Colonia. Los resultados obtenidos muestran la alta importancia económica de las especies animales exóticas en comparación con las nativas durante los primeros momentos de la Colonia temprana. A nivel específico, los bovinos y ovicaprinos (predominio de la cabra sobre la oveja) tienen porcentajes de representación mayores a los suidos. Los datos zooarqueológicos obtenidos han permitido documentar la explotación recurrente, destinada principalmente a la producción cárnica, de las cuatro principales especies domésticas exóticas durante los primeros momentos de contacto colonial en el sitio de PP9.