Binding silver to chitooligosaccharides through N-heterocyclic carbenes: Synthesis and antimicrobial activity Necol, Marcelo R.; Vela Gurovic, Maria Soledad; Ruiz Díaz, Soledad; Silbestri, Gustavo Fabián Silver containing products are widely used as antibacterial agents in wound dressings. The mechanism of action relies on the high reactivity of silver ions, which is also responsible of the lack of selectivity and stability of these products. Stabilization of silver by complexation and binding to a biocompatible material that selectively interacts with microorganisms will certainly lead to improved products. To prove this, chitooligosaccharides and one of its building blocks, D-glucosamine, were complexed with silver through the stable N-heterocyclic carbene (NHC) bond. Two amino moieties from each carbohydrate reacted to form a diimine, which was further converted into an imidazolium salt. This later precursor was complexed to silver to yield the NHCs complexes. The successively generated compounds were spectroscopically characterized by FT-IR, NMR, Inductively Coupled Plasma atomic emission spectroscopy and tested for activity against E. coli, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. The antimicrobial profiles of the silver complexes were similar or better than that of silver nitrate and generally more effective than the antiseptic of reference, PVP iodine. Complexation of silver to biocompatible and microbial selective materials through NHC bonds is a promising approach to develop more efficient silver carriers and wound care products.

Formation of localized magnetic states in silicene in an external electric field Villarreal, J.; Escudero, Federico Nahuel; Ardenghi, Juan Sebastian; Jasen, Paula Verónica In the present work we study theoretically the localized behavior of transition metal adatoms and silicene interaction in an external electrical field. Considering the electron-electron interaction by adding a Hubbard term in the mean-field approximation, we obtain the spin-polarized density of states on the impurity and total density of states in terms of the hybridization strength with the sublattices and the external electric field, showing the possible values for the Hubbard parameter U and the Fermi energy μ at which magnetization arises. In particular, on-site impurities energies below and above the Dirac point are studied, where the magnetization shows a strong dependence on the hybridization parameters of the A and B sublattice with the impurity and a spin-flip transition for critical external electric fields. Finally, a comparison is done between silicene, germanene and stanene, showing no substantial difference when the on-site energy of the impurity is below the Dirac point.

The distribution of symmetry of a naturally reductive nilpotent Lie group Reggiani, Silvio Nicolás We show that the distribution of symmetry of a naturally reductive nilpotent Lie group coincides with the invariant distribution induced by the set of fixed vectors of the isotropy. This extends a known result on compact naturally reductive spaces. We also address the study of the quotient by the foliation of symmetry.

Analogues of Human Granulysin as Antimycobacterial Agents Siano, Alvaro Sebastían; Tonarelli, Georgina Guadalupe; Larpin, Daniel; Imaz, María Susana; Alvarez, Claudia; Zerbini, Elsa Virginia Antimicrobial peptides are essential components of innate defense mechanisms and make promising candidates for novel anti-infective agents. The advantages of these peptides in clinical applications include their potential for broad-spectrum and rapid bactericidal activities, and low propensity for resistance development, whereas possible disadvantages include their high cost, limited stability, and unknown toxicology and pharmacokinetics. Granulysin (Gr) is a cytolytic and proinflammatory molecule expressed by activated human cytotoxic T lymphocytes and natural killer (NK) cells. This paper aims to study bacteriostatic and bactericidal activity against Mycobacterium tuberculosis by synthetic analogues of human Gr between 12 and 26 amino acids (AA) and their acyl derivatives. Considering results of previous studies, five new peptides were designed: a cyclic of 20 AA (Gr-SL1); one of 21 AA (linear) (Gr-SL2), another of 12 AA (cyclic) (Gr-SL3) and two lipopeptides (Gr-SL3-lauric and Gr-SL3-palmitic). Peptides were manually synthesized as C-terminal carboxamides by the solid-phase method following Fmoc chemistry. Gr synthetic analogues were purified by reverse phase HPLC and analyzed by analytical C18RP-HPLC and Maldi Tof. The antimycobacterial activity of synthesized Gr analogues was assessed using a microdilution susceptibility test as described previously. Although peptides studied here had neither higher antimycobacterial activity nor lower toxicity than analogs of human Gr previously evaluated, fresh knowledge concerning the influence of acylation and structural aspects analyzed will optimize the design of novel peptides combining the most favorable aspects for the maintenance of antimycobacterial activity with minimum toxicity.

Hidden paintings, forgotten histories: a micro-stratigraphic approach to study coated rock art Gheco, Lucas Ignacio; Tascon, Marcos; Gastaldi, Marcos Roman; Ahets Etcheberry, Eugenia Inés; Pereda, Soledad; Mastrangelo, Noemi Elisa; Quesada, Marcos Nicolás; Marte, Fernando Daniel Is it possible to detect rock paintings coated by natural or anthropic concretions? In this work, a methodology to discover and characterize underlying paintings is proposed. This approach combines chemical studies by micro-Raman and SEM-EDS of micro-stratigraphic samples taken from the paintings and support rock. As a case of study, it is described the research performed in the archeological site of Oyola in the northwest of Argentina. Strong evidences of red, black, and white hidden paintings have been found. In addition, the method herein presented is thoroughly evaluated pointing out their possibilities and limitations as a tool for the understanding of the historical processes involving production and transformation of the rock art panels. To this end, the methodology was proofed to be a successful exploratory approach for painting detection, expanding its capabilities when complemented with non-invasive characterization techniques.

Los medios de comunicación en la escuela. Cuando la muerte se torna noticia; The media at school. When death turns into news Saez, Virginia; Cerullo, Natalia Carolina El artículo presenta los hallazgos de una investigación socioeducativa sobre los discursos mediáticos de cuatro diarios argentinos, en el período 1993-2011. El objetivo consistió en analizar las características de las prácticas discursivas de las conductas de riesgo y suicidio juvenil en el espacio escolar. Los resultados amplían la base empírica con la que pensar las representaciones de la escuela.; This article introduces the findings of a socioeducative investigation on media discourses of four argentine newspapers, in the 1993-2011 period. The objective was to analyze the characteristics of the discoursive practices of the risk- taking behaviors and juvenile suicide in the school space. The results increase our empirical knowledge to think the representations on school.

Scavenging activity of Dermestes maculatus (Coleoptera: Dermestidae) on burned cadaveric tissue Zanetti, Noelia Inés; Ferrero, A. A.; Centeno, N. D. The aim of this work was to study the effect that fire exposure in tissues may have on Dermestes maculatus DeGeer (Dermestidae: Dermestini) taphonomic behaviour under controlled conditions. Two different times of fire exposure (treatments) were evaluated, 15 min and 30 min, after spraying pig trotters with gasoil. The pig trotters were provided to adult hide beetles and both were maintained at 24 ± 0.1°C, 55.4% ± 2% relative humidity, and a 12:12 h day/night cycle. An unburned pig trotter was used as a control for each treatment. Observations were made and photographs were taken every 4–5 days for 4 months. Qualitative and quantitative analyses were performed. Dermestes maculatus was able to feed and reproduce on burned tissues. Beetles in adult and larvae stages produced different types of marks in several kinds of tissues such as integumental, connective, and muscular, in the controls and treatments. Apparently, 15 min of burning the pig trotters were not sufficient enough to cause differences in the taphonomic marks with respect to the control, but post mortem burning for 30 min may have implicated changes (lesser insect damage represented by lesser number and surface of both depressions and holes were found with respect to the control; greater surfaces and diameters were noticed compared to those found in the unburned pig trotters). The shape of the marks was equal in the controls and treatments.

"Porque nos daba bronca". Las emociones en la acción política de niños/as en una casa tomada; “Because we felt annoyed”. Emotions in the production of the political action of children that live in an occupied house Shabel, Paula Nurit El pensamiento moderno se ha configurado en dicotomías como adultez/infancia y pensar/sentir, que se sintetizan en una división permanente entre lo racional y lo irracional desde donde se ha analizado la acción humana. Sin embargo, la antropología ha desarrollado diversas líneas de trabajo que problematizan estos esquemas aportando otras miradas sobre la niñez y sobre la movilización política. En este mismo sentido, y a partir de un extenso estudio etnográfico, nos proponemos analizar los modos en los que los/as niños/as de entre 8 y 15 años que viven en una casa tomada de la Ciudad de Buenos Aires producen acciones políticas colectivas enraizadas en sus emociones compartidas.; Modern thought has been configured in dichotomies such as adulthood/infancy and thinking/feeling, which are synthesized in a permanent division between the rational and the irrational from where human action has been analyzed. However, anthropology has developed several lines of work that problematize these schemes providing alternative views on childhood and on political mobilization. In this same sense, and from an extensive ethnographic study, we propose to analyze the ways in which children between the ages of 8 and 15 living in an occupied house from the City of Buenos Aires produce collective political actions rooted in their shared emotions.

The evolution of ultra-massive white dwarfs Camisassa, María Eugenia; Althaus, Leandro Gabriel; Corsico, Alejandro Hugo; de Gerónimo, Francisco César; Miller Bertolami, Marcelo Miguel; Novarino, Maria Leonela; Rohrmann, Rene Daniel; Wachlin, Felipe Carlos; García Berro, Enrique Ultra-massive white dwarfs are powerful tools used to study various physical processes in the asymptotic giant branch (AGB), type Ia supernova explosions, and the theory of crystallization through white dwarf asteroseismology. Despite the interest in these white dwarfs, there are few evolutionary studies in the literature devoted to them. Here we present new ultra-massive white dwarf evolutionary sequences that constitute an improvement over previous ones. In these new sequences we take into account for the first time the process of phase separation expected during the crystallization stage of these white dwarfs by relying on the most up-to-date phase diagram of dense oxygen/neon mixtures. Realistic chemical profiles resulting from the full computation of progenitor evolution during the semidegenerate carbon burning along the super-AGB phase are also considered in our sequences. Outer boundary conditions for our evolving models are provided by detailed non-gray white dwarf model atmospheres for hydrogen and helium composition. We assessed the impact of all these improvements on the evolutionary properties of ultra-massive white dwarfs, providing updated evolutionary sequences for these stars. We conclude that crystallization is expected to affect the majority of the massive white dwarfs observed with effective temperatures below 40 000 K. Moreover, the calculation of the phase separation process induced by crystallization is necessary to accurately determine the cooling age and the mass-radius relation of massive white dwarfs. We also provide colors in the Gaia photometric bands for our H-rich white dwarf evolutionary sequences on the basis of new model atmospheres. Finally, these new white dwarf sequences provide a new theoretical frame to perform asteroseismological studies on the recently detected ultra-massive pulsating white dwarfs.

Assessment of the sustainable potential of parking lots in Bahía Blanca City, Argentina Gentili, Jorge Osvaldo; Fernández, María Eugenia; Ortuño Cano, María de Los Ángeles; Campo, Alicia María The aim of this study is to characterize the site, location, and morphology of parking lots in downtown Bahía Blanca; to determinetheir contribution to environmental urban problems; and to suggest strategies to turn them into spaces in which to apply newurban principles. Strategies related to sustainable urban development, with comprehensive solutions for energy efficiency,sustainable construction, biomass conservation, and resource optimization were considered. The results show that parking lotshave increased as urban land use typology within the city downtown. It was observed that parking lots are concentrated in someareas of the city downtown, and that concrete and sheet metal are the main construction materials. The lack of vegetation is also amajor characteristic. Their location in urban areas implies vehicle circulation on downtown streets and avenues, which is directlyassociated to atmospheric pollution. Finally, each parking lot potential was analyzed in order to implement sustainabledevelopment measures, related to green policies, design, and construction.

El mapa social de la Aglomeración Gran Buenos Aires como evidencia empírica de modelos urbanos Buzai, Gustavo Daniel; Marcos, Mariana El trabajo tiene como objetivo realizar un análisis del mapa social de la Aglomeración Gran Buenos Aires a partir de la aplicación técnica de procedimientos de análisis multivariado -la asociación espacial por superposición temática- y teniendo como marco conceptual aspectos modelísticos de la estructura socioespacial de las grandes ciudades de América Latina. Para lograr este objetivo, además del análisis de modelos urbanos, se seleccionan variables de entre los datos más recientes disponibles -Censo 2001-, que claramente presentan una dicotomía entre situaciones favorables y desfavorables, y se aplica una metodología de estandarización que lleva a la obtención de puntajes de clasificación espacial como síntesis de las relaciones. De esta manera, se obtienen resultados parciales que presentan situaciones contrastantes, las cuales se combinan en un resultado final en el que, a su vez, se incorporan entidades geográficas puntuales como las urbanizaciones cerradas y los asentamientos precarios, ambos representantes de niveles socioeconómicos claramente opuestos.

Video summarisation by deep visual and categorical diversity Atencio, Pedro; Sanchez Torres, German; Branch, John; Delrieux, Claudio Augusto The authors propose a video-summarisation method based on visual and categorical diversities using pre-trained deep visual and categorical models. Their method extracts visual and categorical features from a pre-trained deep convolutional network (DCN) and a pre-trained word-embedding matrix. Using visual and categorical information they obtain a video diversity estimation, which is used as an importance score to select segments from the input video that best describes it. Their method also allows performing queries during the search process, in this way personalising the resulting video summaries according to the particular intended purposes. The performance of the method is evaluated using different pre-trained DCN models in order to select the architecture with the best throughput. They then compare it with other state-of-the-art proposals in video summarisation using a data-driven approach with the public dataset SumMe, which contains annotated videos with per-fragment importance. The results show that their method outperforms other proposals in most of the examples. As an additional advantage, their method requires a simple and direct implementation that does not require a training stage.

Evidence of developmental escape from transcriptional gene silencing in MESSI retrotransposons Sanchez, Diego Hernan; Gaubert, Hervé; Yang, Weibing Transposable elements (TEs) are ubiquitous genomic features. ‘Copy-and-paste’ long-terminal-repeat (LTR) retrotransposons have been particularly successful during evolution of the plant kingdom, representing a substantial proportion of genomes. For survival in copious numbers, these TEs may have evolved replicative mobilization strategies that circumvented hosts’ epigenetic silencing. Stressful circumstances are known to trigger the majority of known mobilizing plant retrotransposons, leading to the idea that most are activated by environmental signals. However, previous research revealed that plant developmental programs include steps of silencing relaxation, suggesting that developmental signals may also be of importance for thriving parasitic elements. Here, we uncover an unusual family of giant LTR retrotransposons from the Solanum clade, named MESSI, with transcriptional competence in shoot apical meristems of tomato. Despite being recognized and targeted by the host epigenetic surveillance, this family is activated in specific meristematic areas fundamental for plant shoot development, which are involved in meristem formation and maintenance. Our work provides initial evidence that some retrotransposons may evolve developmentally associated escape strategies to overcome transcriptional gene silencing in vegetative tissues contributing to the host's next generation. This implies that not only environmental but also developmental signals could be exploited by selfish elements for survival within the plant kingdom

Superresolution method for a single wide-field image deconvolution by superposition of point sources Martinez, Sandra Rita; Toscani, Micaela; Martinez, Oscar Eduardo In this work, we present a new algorithm for wide‐field fluorescent micrsocopy deconvolution from a single acquisition without a sparsity prior, which allows the retrieval of the target function with superresolution, with a simple approach that the measured data are fit by the convolution of a superposition of virtual point sources (SUPPOSe) of equal intensity with the point spread function. The cloud of virtual point sources approximates the actual distribution of sources that can be discrete or continuous. In this manner, only the positions of the sources need to be determined. An upper bound for the uncertainty in the position of the sources was derived, which provides a criteria to distinguish real facts from eventual artefacts and distortions. Two very different experimental situations were used for the test (an artificially synthesized image and fluorescent microscopy images), showing excellent reconstructions and agreement with the predicted uncertainties, achieving up to a fivefold improvement in the resolution for the microscope. The method also provides the optimum number of sources to be used for the fit.

Problemas públicos y configuración de colectivos. Una reflexión analítica sobre el pasaje al espacio público y sus condiciones de mediatización; Public problems and constitution of collectives. An analytical reflection on the passage to public space and its mediatization conditions Fernández, Mariano Néstor El siguiente artículo es una reflexión conceptual y analítica sobre la problemática —sociológica y comunicacional— de la constitución de colectivos y su pasaje al espacio público. El texto propone una hipótesis teórica con consecuencias metodológicas: que la estructura de configuración de los colectivos es triádica y no binaria, tal y como las teorías de la identidad colectiva suelen postular. Los colectivos, entonces, se constituyen, primero, en un proceso de colectivización interna, luego a través de la configuración de un campo de relaciones intercolectivas (el momento identitario) y, una vez que ingresan en el espacio público, necesitan de los discursos que les proveen una certificación pública de existencia. Sobre esta base, se sugieren algunas ideas de proceder metodológico para la indagación empírica a partir de estudios de caso.; The following article is a conceptual and analytical reflection on the problematic —sociological and communicational— of the constitution of collectives and their passage to the public space. The text proposes a theoretical hypothesis with methodological consequences: that the configuration structure of collectives is triadic and not binary, as theories of collective identity usually postulate. Collectives, then, are constituted, first, in a process of internal collectivization, then through the configuration of a field of intercollective relations (the identitary moment) and, once they enter the public space, they need the discourses that provide them a public certification of existence. On this basis, some ideas are suggested to proceed methodologically for empirical inquiry from case studies.

Una investigación teatral y fílmica sobre el trabajo: Algunas obras de Gerardo Naumann Contreras, Sandra Claudia This paper is a reading of Gerardo Naumann’s plays and films shown as a theatrical and performative investigation into the world of labor (his plays Los trabajos improductivos andFábrica,and his films El trabajo industrial and Ricardo Bar). Our approach is based on three hypotheses: 1) Naumann's nonproductive labors (stealing, acting) explore and exhibit virtuosity—i.e. the articulation between memory, repetition and the use of words--as a field of experimentation; 2) by displacing performers from their social location (their status of workers, indistrial or nonproductive workers), Nauman’s theatrical experimentation with the worker-performers’ voices is both a political experimentation as well as an inquiry into new forms of community and subjectivation; 3) Naumann's vital involvement in his own performances playing a worker establishes a frame of reference so that the exploration of the world of labor becomes the (ambivalent) register of the “bargaining” position of artists with non-actors, nonproductive workers, and worker actors.

Erratum: Rotating planar gravity currents at moderate Rossby numbers: Fully resolved simulations and shallow-water modelling (Journal of Fluid Mechanics (2019) DOI: 10.1017/jfm.2019.152) Salinas, Jorge Sebastián; Bonometti, Thomas; Ungarish, Marius; Cantero, Mariano Ignacio First, we wish to clarify that in equations (3.14)-(3.15) of Salinas et al. (2019) all variables are dimensional except for the angular velocity ω and the coefficient k. After (3.15), we switch to dimensionless variables for the streamwise direction x, the front location xN, the Ekman layer δ E, the local height h (scaled by the initial height h0) and time t (scaled by 1/Ω=, with Ω the angular velocity of the rotating system). (Formula Presented). During spin-up the estimated Ri increases because decreases, and for the values of Re, Sc and C of our DNS the typical Ri is larger than 0.25. We also note that a sharp density transition layer enhances stability, and indeed the spin-up model without mixing shows better agreement for DNS with large Sc.

El territorio, la comunidad y la autonomía: ¿Discursos mitológicos en los programas sociales destinados a jóvenes "en riesgo"? Medan, Marina Desde inicios del 2000 en la Argentina se implementan programas de inclusión social y prevención social del delito destinados a jóvenes “en riesgo”, en los cuales el abordaje territorial y comunitario es distintivo. Este artículo describe y analiza los sentidos y prácticas que tal enfoque supone, tanto desde la perspectiva de los agentes institucionales como desde la de los jóvenes. Los resultados se discuten a la luz de la literatura que aborda las relaciones entre el Estado, el territorio y la comunidad, y se resalta el potencial analítico de la noción de “margen” (Das y Poole, 2008) para problematizar el funcionamiento estatal. Finalmente, se coloca una nueva hipótesis a partir de los hallazgos: las definiciones institucionales sobre el territorio y la comunidad como epicentro de los riesgos que aquejan a los jóvenes, en articulación con la reivindicación de la autonomía juvenil para lidiar con ellos, podría generar un discurso mitológico (Haney, 2010) que provocara más desempoderamiento que emancipación. Los datos analizados provienen de investigaciones cualitativas desarrolladas entre 2008 y 2018, cuyas técnicas principales han sido la observación participante, entrevistas en profundidad y grupos focales. La referencia empírica está conformada por programas de prevención social del delito y programas de inclusión social juvenil implementados en barrios populares del AMBA.; Since 2000 in Argentina, social inclusion and crime prevention programs have been implemented for youth “at risk”, in which the community approach is distinctive. This article describes and analyses the senses and practices implied in such an approach, both from institutional agents and youth perspectives. Results are discussed through literature that deals with the relations between State, territory and community. Within that framework, the notion of “margin” (Das and Poole, 2004) is used to problematize the state practices. Finally, a new hypothesis emerged from the findings: the institutional definitions of territory and community as the centre of the risks that affect young people, in articulation with the demand for youth autonomy to deal with them, could generate a mythological discourse (Haney, 2010) that would cause more disempowerment than emancipation. The analysed data come from qualitative research developed between 2008 and 2018. Participant observation, in-depth interviews and focus groups have been the main techniques. The empirical references are social inclusion and crime prevention programs implemented in popular neighborhoods of the metropolitan area of Buenos Aires.

A relational account of communication on the basis of slips of the tongue Gil, Jose Maria They are a good deal more than amusing (or embarrassing) errors of speech. The collection and analysis of such errors provides important clues to how speech is organized in the nervous system. Victoria A. Fromkin (1973: 110) Also, most current linguistics fails to consider various kinds of anomalous data which actually reveal very important information about the structure of the mental system which underlies our linguistic abilities, including slips of the tongue and unintentional puns. Sydney M. Lamb (1999: 9) Abstract The socio-cognitive approach to pragmatics [SCA] is based on two fundamental hypotheses: (1) speaker and hearer are equal participants in the communicative process, (2) communication is the result of the interplay of intention and attention, as this interplay is motivated by the individuals' private socio-cultural backgrounds. In this paper, I aim at showing that relational network theory (which has been mainly developed by the American neurolinguist Sydney M. Lamb) allow us to account not only for aspects corresponding to intention or attention, but also for "smooth communication" and "bumpy communication" (being the latter the dimension which includes unintended meanings). Four actual slips of the tongue will be relevant examples thanks to which it can be recognized how cooperation and intention are in a highly complex interaction together with the substantial elements of the individual traits: attention, private experience, egocentrism, and salience. Within this context, the relational account is epistemologically crucial. Firstly, it allows us to represent the neurocognitive structures that enable a person to produce or understand utterances. Secondly, it helps us to suggest that canonical pragmatics (like Speech Acts Theory, Gricean Pragmatics, Relevance Theory) cannot even consider actual and relevant phenomena like slips of the tongue, because they focus on cooperative intention and they neglect (or discard) egocentric attention.

Las derrotas de Alberto Méndez: memoria y duelo en Los girasoles ciegos (2004); Alberto Méndez´s derrotas: memory and grief in Los girasoles ciegos (2004) Giménez, Facundo Ezequiel El libro de Alberto Méndez, Los girasoles ciegos (2004), se publica en el contexto de un boom memorístico que, en España, tuvo como centro a los sucesos de la guerra civil y la posguerra franquista. El siguiente trabajo se propone analizar, en principio, la polisemia de la palabra «derrota» con que Méndez titula los cuatro relatos del libro, para luego, observar los alcances de este término en la construcción de una memoria colectiva. El volumen en cuestión, en este sentido, será abordado menos como una reconstrucción histórica, que como una intervención en la memoria traumática de la derrota. De este modo, se observará cómo Los girasoles ciegos propone la necesidad de un trabajo de duelo y de una escena de perdón.; Los girasoles ciegos (2004) written by Alberto Méndez, was published in the context of a memorial boom in Spain, characterized by the events of the civil war and its aftermath. The purpose of this paper is to analyze, at first, the polysemic word «derrota», which Méndez uses to name the four short stories of the book, and later, to examine the role played by this word in the construction of collective memory. This volume will not be approached as a historical reconstruction, but rather as an intervention in the traumatic memory of defeat. This paper will thus develop how Los girasoles ciegos illustrates the need of a grieving process and a forgiveness scene.