Estudiantes en contextos de educación a distancia. Variables vinculadas con el logro académico; Students in distance education contexts. Variables linked to academic achievement Chiecher, Analía Claudia El artículo toma como punto de partida las altas cifras de abandono que caracterizan a la educación a distancia y, por el contrario, los bajos porcentajes de estudiantes que consiguen cursar trayectorias ajustadas a los tiempos que establece el plan de estudios. El objetivo del escrito se orienta a analizar perfiles de un grupo de estudiantes de primer año, de modalidad a distancia, cuyas trayectorias se ciñeron a la progresión temporal fijada por el plan de estudios. Se realizó un estudio no experimental y descriptivo en el cual participaron estudiantes de primer año de carreras de grado dictadas a distancia, quienes cumplían, además, la condición de haber regularizado todas las asignaturas previstas en el plan de estudios. Para la recolección de datos se administró un cuestionario de autoinforme, que recaba información sobre variables personales y contextuales con posible incidencia en las trayectorias académicas. Los resultados muestran que, entre las variables personales consideradas en el estudio, aquellas que parecen tener vinculación con trayectorias de logro son el nivel educativo de los padres, las metas de aprendizaje y las atribuciones causales internas y modificables. Asimismo, las variables contextuales percibidas como promotoras del logro se vincularon principalmente con la disponibilidad del profesor y su rapidez para responder consultas y ofrecer devoluciones de las actividades realizadas. La discusión propone líneas de acción que, sustentadas en los resultados del estudio, podrían contribuir a la promoción del logro estudiantil en la educación a distancia.

Hotspot of tadpole abnormality in suburban south-west Florida Anzaldua, Sharon Pratt; Goldberg, Francisco Javier A high concentration of Cuban treefrog (Osteopilus septentrionalis) tadpoles displaying morphological abnormalities was discovered in an untreated swimming pool in Bonita Springs, Florida. This find initiated a 4-year survey (2012-2015) of surrounding roadside drainage ditches that had been treated with insecticide for mosquito control. The study was extended to the populations of Ave Maria, Florida, and Everglades National Park. The core data set of 36,550 tadpoles from the swimming pool and ditches contained 25,136 abnormal tadpoles, an abnormality average of 68.8 %, well above the 5 % minimum definition for a hotspot. The frogs from Ave Maria and the Everglades National park were 0 % abnormal. The type of tadpole abnormality differed between the suburban treated roadside drainage ditches versus the untreated swimming pool, although the same abnormalities were found in both the suburban treated and untreated water. In the untreated swimming pool, 70.1 % of tadpoles displayed abnormalities such as bent tails, abnormal limbs, and disfigured or absent
mouthparts. Larvae in the untreated swimming pool metamorphosed en masse despite abnormalities. The high frequency of abnormal metamorph abnormalities found were: kyphosis, scoliosis, microcephaly, and forelimb abnormalities. In the treated roadside drainage ditches, Gosner stage 16-25 tadpoles could not undergo metamorphosis and experienced mass mortality. The abnormalities found at Gosner stage 16 of the embryo were in the head and body. Tadpoles at Gosner stages 19-25 failed to develop gills, were bloated, had growth retardation, and mouthpart abnormalities. The older Gosner stage 25-41 tadpole populations in the ditches showed bloating, lumps, emaciation, and growth retardation. A brief synopsis of O. septentrionalis treefrog biology is also given, including breeding congregations, average 8 hour time to hatching, and 19 days metamorphosis.

El archivo de Manuel Molina: continuidades y rupturas en la lingüística patagónica del siglo XX; Manuel Molina´s archive: continuities and breaks in Patagonian linguistics of the 20th century Dominguez, Verónica Soledad; Orden, María Emilia Hacia fines del siglo XIX desde la congregación salesiana se realizaron documentaciones lingüísticas sobre las lenguas de la Patagonia. Posteriormente, esta práctica misionera cayó en desuso debido a la modificación de la realidad lingüística de la zona y de los cambios en los objetivos de esta congregación católica. A mediados del siglo XX Molina concibió un proyecto de resurgimiento de la lingüística misionera, que implicó la puesta en valor de los aportes de los salesianos junto con la continuación de sus prácticas de registro. En esta búsqueda recuperó fuentes bibliográficas de anteriores salesianos, entabló encuentros con hablantes de distintas lenguas patagónicas. En este artículo nos proponemos analizar su metodología de trabajo, el aporte de los consultantes y la selección de materiales que finalmente prioriza para su edición. Nos centraremos en el cotejo de sus materiales de archivo, para dilucidar las diferencias entre la documentación existente en el gabinete y lo que efectivamente publica.; Toward the end of the 19th Century, linguistic registers on the Patagonian languages were made by the Salesian congregation. This missionary practice fell into disuse later, due to the modification of the linguistic reality of the zone and the change of this Catholic Congregation’s objectives. In the middle of the 20th Century, Molina conceived a project of resurgence of the missionary linguistic practices that implied the value of the Salesian contributions as well as the continuation of their registration practices. During this research, he recovered bibliographical sources and met with speakers of various Patagonian languages. This paper analyzes his work methodology, the native speakers’ contributions and the selection of published material. It is focused on the comparison of Molina’s records in order to elucidate the differences between the collected material and the published one.

Polyamine Colloids Cross‐Linked with Phosphate Ions: Towards Understanding the Solution Phase Behavior Herrera, Santiago Esteban; Agazzi, Maximiliano Luis; Cortez, María Lorena; Marmisollé, Waldemar Alejandro; Tagliazucchi, Mario Eugenio; Azzaroni, Omar Ionically crosslinked poly(allylamine)/phosphate (PAH/Pi) colloids consist of self‐assembled nanostructures stabilized by supramolecular interactions. Under physiological conditions, these interactions should be present at high ionic strength and only in a narrow pH window to be effective as drug delivery agents. In this work we study the effect of the pH and ionic strength in the chemical behaviour of inorganic phosphate (Pi), poly(allylamine hydrochloride) (PAH) and their mixture in aqueous solution (PAH−Pi). By combination of experimental measurements and a theoretical model, we demonstrate that the driving force that leads to the formation of colloids is the electrostatic pairing between the positively charged amino groups in PAH and negatively charged HPO42− ions. Increasing the ionic strength of the system by addition of KCl weakens the PAH−Pi interactions and narrows the pH stability window from 4 to 1.8 pH units. In addition, a fully reversible system was obtained in which the colloids assemble and disassemble by changing the pH between 6.8 and 7.1 at high ionic strength, making them suitable for use as pH‐responsive nanocarriers.

Dragonflies and damselflies (Odonata) from Córdoba and San Luis provinces, Argentina Márquez, Javier Andrés; Principe, Romina Elizabeth; Berejnoi, Diego E.; Rodríguez, José S.; Bedano, José Camilo; Molineri, Carlos Nineteen geographical records for species of Odonata in 2 provinces of Argentina are documented. We provided records for 9 newly recorded species for Córdoba: Lestes spatula Fraser, 1946, Andinagrion peterseni (Ris, 1908), Argentagrion ambiguum (Ris, 1904), Erythemis attala (Selys in Sagra, 1857), Erythemis plebeja (Burmeister, 1839), Erythrodiplax media Borror, 1942, Micrathyria longifasciata Calvert, 1909, Micrathyria hypodidyma Calvert, 1906, and Tramea cophysa Hagen, 1867. In San Luis, we provided records for 10 newly recorded species: Hetaerina rosea Selys, 1853, Acanthagrion lancea Selys, 1876, Ischnura fluviatilis Selys, 1876, Oxyagrion rubidium (Rambur, 1842), Castoraeschna decurvata Dunkle & Cook, 1984, Rhionaeschna pallipes (Fraser, 1947), Phyllocycla argentina (Hagenin Selys, 1878), Erythrodiplax corallina (Brauer, 1865), Perithemis mooma Kirby, 1889, and Planiplax erythropyga (Karsch, 1891). Among these records, we extend the geographic distribution of A. peterseni and R. pallipes, which areendemic to Argentina and recorded P. erythropyga for the first time in Chaco phytogeographic province

Application of quality indicators to data from the National Network of Congenital Anomalies of Argentina Groisman, Boris; Barbero, Pablo Miguel; Mastroiacovo, Pierpaolo; Botto, Lorenzo; Bidondo, Maria Paz; Liascovich, Rosa Background: In Argentina, birth defects are a leading cause of infant deaths. In 2009, the National Network for Congenital Anomalies of Argentina (RENAC) was established as a hospital-based surveillance system of major structural birth defects. To assess and enhance the system's data quality, we previously developed data quality indicators (DQI). Our aim was to evaluate quality indicators in RENAC. Methods: We applied the DQI presented in a related publication to the 2016 RENAC data. Results: Among the DQI of description, spina bifida coverage and talipes had the lowest results. Regarding prevalence of hypospadias, it was lower than the defined threshold. RENAC did not achieve the ascertainment threshold of a prevalence of 21.5 per 10,000 for critical congenital heart defects. There was a high ratio of spina bifida to anencephaly. Conclusions: DQI provide a focus for improving quality, making decisions, and advocating for interventions. Examples include advocating for newborn screening of critical congenital heart defects with pulse oximetry; developing training programs for clinicians to improve the detection of isolated hypospadias; and developing visual tools and checklists to improve the completeness and accuracy of case description for spina bifida, talipes, and other major malformations. After the interventions, it is important to track the impact by measuring again the DQI.

Why Should We Become Posthuman? The Beneficence Argument Questioned Vaccari, Andrés Why should we become posthuman? There is only one morally compelling answer to this question: because posthumanity will be a more beneficial state, better than present humanity. This is the Posthuman Beneficence Argument (PBA), the centerpiece of the liberal transhumanist defense of "directed evolution." In this article, I examine PBA and find it deficient on a number of lethal counts. My argument focuses on the writings of transhumanist philosopher Nick Bostrom, who has developed the most articulate defense of PBA and disclosed its metaethical framework. I begin by locating PBA in the context of wider transhumanist claims for the desirability of posthumanity. I identify two crucial components: (1) a model of deliberative rationality, requiring reasons to endorse claims; and (2) the reasons themselves (i.e., the greater beneficence that posthumanity represents). I examine these two conditions, in turn, specifying the claims that they ask us to accept. Following Bostrom, I argue that there is a need for a foundationalist approach that assures us of some universality in the process of valuation. This is required to appropriately ground the moral continuity and appeal to universality that PBA demands. I examine the reasons why this approach ultimately fails, leaving posthumanity as an unintelligible concept with no moral force. I conclude by identifying (and endorsing) a more mature approach to the debate on human enhancement, one that forfeits the grandiose but baseless claims too often found in transhumanist defenses of directed evolution. In short, posthumanity may be a good science fiction trope, but it has no normative force in the moral philosophy of human enhancement.

Protección de datos personales. Especial referencia al proyecto de reforma de la ley Argentina Nº 25.326; Personal data protection. Special reference to the reform project of the argentine law No 25,326 Juri, Yamila Eliana Los avances operados en el mundo de la tecnología como de las relacionesjurídicas, hacen necesaria una actualización en materia de protección de datos personales. En este sentido analizamos someramente los puntos principales del proyecto de reforma que en este momento se discute en el Congreso Nacional a fin de adecuar nuestra legislación argentina a los estándares internacionales en esta materia.; The advances made in the world of technology as well as legal relations require an update on the protection of personal data. In this sense, we briefly analyze the main points of the reform project that is being discussed at the National Congress in order to adapt our Argentine legislation to international standards in this matter.

La ingratitud, de Matilde Sánchez: identidad y viaje; Matilde Sánchez’s La ingratitud: identity and travel Conde de Boeck, José Agustín; Cohen, Elisa Beatriz Centrada en el autoexilio de una joven mujer argentina en Europa, lanovela La ingratitud de Matilde Sánchez construye todo un sistema de representaciónen torno al contacto con una comunidad lingüística diferente y, a suvez, extiende esta alteridad hacia las tensiones identitarias entre lo femenino ylo masculino, la relación padre e hija, la juventud y la vejez, la soledad y la convivencia,lo nacional y lo extranjero, todo lo cual da cuenta del complejo trasfondode la realidad política y social de Argentina y de los alcances ideológicos de laescritura como estrategia para reconstruir una identidad escindida. A través delrecurso de lo epistolar y del monólogo interior, la novela de Sánchez motorizauna problemática que será axial a lo largo de toda su escritura: la relación entrela experiencia subjetiva, la memoria y el discurso de la mujer como parte de unacomunidad lingüística determinada.; Focused in the auto-exile of a young Argentine woman in Europe, Matilde Sanchez’s novel La ingratitud builds a whole system of representation around the contact with a different linguistic community and, at the same time, it extends that otherness toward the idenitity tensions between feminine/mas- culine, father-daughter relationship, youth/eld, solitude/coexistence, national/ foreign. All this involves Argentine complex background of political and social reality as well as ideological literary writing power to rebuild a defragmented so- cial identity. Through literary resources as epistolary writing and stream of con- sciousness, Sánchez’s novel shows a problematic that will be essential through-out her entire work: relationship between subjective experience, memory and women discourse as part of a particular linguistic community.

Adopción internacional: legalmente permitida, fácticamente prohibida Feuillade, Milton César En materia de adopción es claro que el legislador realizó mejoras en los textos legales, pero conceptualmente no ha querido cambiar el sistema, al punto tal que en la sanción del Código Civil y Comercial se quitó la cooperación. Tampoco se avizora la voluntad de ratificar la Convención de la Haya de 1993 sobre Protección del Niño y a la Cooperación en materia de Adopción Internacional, sumado a que la norma que establece los cinco años de residencia en el país para los extranjeros la hace de difícil implementación. Respecto a los adoptantes residentes en el país, el sistema del RUAGA requeriría reformas para las adopciones internacionales. Desde este panorama, como dice el título de este trabajo, hoy la adopción internacional está legalmente permitida y fácticamente prohibida.

Paleogeographic reconstruction of the Tar – San Martín lacustrine system during late Pleistocene to early Holocene: Landscape availability and hunter-gatherer circulation (Santa Cruz, Argentina) Horta, Luis Rubén; Belardi, Juan Bautista; Georgieff, Sergio Miguel; Carballo Marina, Flavia Elena This paper presents the paleogeographic reconstructions of flooded areas of the Tar - San Martín lacustrine system during the late Pleistocene - Holocene. The dimensions of lacustrine and glaciolacustrine levels of this basin are higher than the current levels of the lakes. The organic matter of lake levels recorded on stratigraphic profiles was described, sampled and dated using AMS, while other paleobathymetric indicators were also identified (height of the fan-delta apex and paleo-coast levels). Deriving out of the reconstruction of flooded areas it was established that the lake system was formed before 28 ka ago and would have reached its maximum expansion around 12 ka ago. The first hunter-gatherer occupation of the basin (11 ka)corresponds to the period of initial contraction of the lake system and the composition of the current configuration of the coastlines. This scenario would have allowed the exploration of western areas and the gradual incorporation of the forest to the action range of hunter-gatherer populations. Similarly, the levels of lakes Tar and San Martín would not have hindered the movement of human populations through the steppe throughout the Holocene.

Variación altitudinal de caracteres fenológicos y crecimiento inicial en condiciones controladas entre poblaciones de Nothofagus pumilio provenientes del Centro-Oeste de Chubut, Argentina; Altitudinal variation of phenological characters and initial growth under controlled conditions among Nothofagus pumilio populations from Center-West Chubut, Argentina Mondino, Victor Alejandro; Pastorino, Mario Juan; Gallo, Leonardo Se estudió la diferenciación altitudinal de seis poblaciones naturales argentinas de lenga (Nothofagus pumilio) del Centro Oeste de laProvincia de Chubut (42° 50´ S) distribuidas en un rango altitudinal de 500 m (1.000 a 1.500 m s.n.m.) a través de ensayos de ambientecomún en invernadero. Se ajustaron curvas individuales de crecimiento en plantines de un año utilizando la ecuación de Boltzmann(regresión no-lineal). Por medio de ANDEVA se analizó la variación inter-poblacional en diversos parámetros de las curvas ajustadas,indicadores del aumento y la fenología del proceso de crecimiento. Se probaron diferencias significativas entre las poblaciones delpiso altitudinal superior y las de los pisos altitudinales intermedio y bajo para la iniciación y la duración del periodo de crecimiento,evidenciando un tipo de variación ecotípica. Los resultados prueban la necesidad de considerar la altitud del origen de las semillas enprogramas de restauración ecológica o plantación comercial con la especie.; The genetic differentiation of six natural Argentine populations of lenga (Nothofagus pumilio) from the Center West of the Province of Chubut (42 ° 50 'S) distributed in an altitudinal range of 500 m (between 1,000 and 1,500 m a.s.l.) was studied by means of common garden greenhouse trials. Individual growth curves were fitted in one-year-old seedlings using the Boltzmann equation (non-linear regression). Inter-population variation was analyzed with ANOVA in several parameters of the fitted curves, indicative of the increase and the phenology of the growth process. Significant differences were shown between the upper populations and those of the intermediate and lower altitudinal level for the initiation and duration of the growth period, evidencing an ecotypic variation. Our results point out the relevance of considering the altitude of the seed origin in programs of ecological restoration or commercial plantation with lenga.

Gigantic mysticete predators roamed the Eocene Southern Ocean Marx, Felix G.; Buono, Mónica Romina; Evans, Alistair R.; Fordyce, Robert Ewan; Reguero, Marcelo Alfredo; Hocking, David P. Modern baleen whales (Mysticeti), the largest animals on Earth, arose from small ancestors around 36.4 million years ago (Ma). True gigantism is thought to have arisen late in mysticete history, with species exceeding 10 m unknown prior to 8 Ma. This view is challenged by new fossils from Seymour Island (Isla Marambio), Antarctica, which suggest that enormous whales once roamed the Southern Ocean during the Late Eocene (c. 34 Ma). The new material hints at an unknown species of the archaic mysticete Llanocetus with a total body length of up to 12 m. The latter is comparable to that of extant Omura´s whales (Balaenoptera omurai Wada et al. 2003), and suggests that gigantism has been a re-occurring feature of mysticetes since their very origin. Functional analysis including sharpness and dental wear implies an at least partly raptorial feeding strategy, starkly contrasting with the filtering habit of living whales. The new material markedly expands the size range of archaic mysticetes, and demonstrates that whales achieved considerable disparity shortly after their origin.

Ant community patterns in highly fragmented Chaco forests of central Argentina Pereyra, Mariana; Pol, Rodrigo Gabriel; Galetto, Leonardo The Chaco is the largest dry forest biome in South America and one of the regions most threatened by agricultural intensification. As a consequence, in several areas Chaco forests persist as forest remnants of different sizes embedded in an agricultural matrix. Ants are social insects that have key roles in ecosystem functioning, and the effects of this ongoing land use change process on ant communities are little known for this region. In the present study, we assessed the consequences of land use replacement by monocultures and forest fragmentation on ant communities. Particularly, we assessed whether patch size, patch isolation and edge effect affect species richness and composition of ground-dwelling ants in fragmented landscapes of Chaco forests. We collected ants by combining hand collecting and pitfall traps in 17 forest fragments and the surrounding matrix from two sites in Córdoba, Argentina. Patch size and patch isolation had no effect on ant richness; however, patch isolation and, to a lesser extent, patch size altered ant species composition. The ant community was not affected by edge but it was negatively affected by the crop matrix, which reduced richness and altered species composition. These results indicate that monoculture matrices severely affect ant communities in the Chaco forests, and that the effects of other indicators of habitat fragmentation (patch size and edge effect) are subtler and less relevant. In the present context of land use change, even small fragments could have an important value for the conservation of ant diversity.

Systematic study of truffles in the genus Ruhlandiella, with the description of two new species from Patagonia Kraisitudomsook, Nattapol; Healy, Rosanne A.; Mujic, Alija B.; Pfister, Donald H.; Nouhra, Eduardo Ramon; Smith, Matthew E. Ruhlandiella is a genus of exothecial, ectomycorrhizal fungi in the order Pezizales. Ascomata of exothecial fungi typically lack a peridium and are covered with a hymenial layer instead. Ruhlandiella species have nonoperculate asci and highly ornamented ascospores. The genus was first described by Hennings in 1903 to include the single species, R. berolinensis. Since then, mycologists have uncovered Ruhlandiella species in many locations around the globe, including Australia, Spain, Italy, and the USA. Currently, there are four recognized species: R. berolinensis, R. peregrina, R. reticulata, and R. truncata. All were found near Eucalyptus or Melaleuca trees of Australasian origin. Recently, we discovered two new species of Ruhlandiella in Nothofagaceae forests in South America. They regularly form mitotic spore mats directly on soil in the forests of Patagonia. Here, we formally describe these new species and construct the phylogeny of Ruhlandiella and related genera using a multilocus phylogenetic analysis. We also revise the taxonomy of Ruhlandiella and provide an identification key to accepted species of Ruhlandiella.

Instrumentation for solar spectropolarimetry: state of the art and prospects Iglesias, Francisco Andres; Feller, Alex Given its unchallenged capabilities in terms of sensitivity and spatial resolution, the combination of imaging spectropolarimetry and numeric Stokes inversion represents the dominant technique currently used to remotely sense the physical properties of the solar atmosphere and, in particular, its important driving magnetic field. Solar magnetism manifests itself in a wide range of spatial, temporal, and energetic scales. The ubiquitous but relatively small and weak fields of the so-called quiet Sun are believed today to be crucial for answering many open questions in solar physics, some of which have substantial practical relevance due to the strong Sun?Earth connection. However, such fields are very challenging to detect because they require spectropolarimetric measurements with high spatial (sub-arcsec), spectral (<100  mÅ), and temporal (<10  s) resolution along with high polarimetric sensitivity (<0.1  %   of the intensity). We collect and discuss both well-established and upcoming instrumental solutions developed during the last decades to push solar observations toward the above-mentioned parameter regime. This typically involves design trade-offs due to the high dimensionality of the data and signal-to-noise-ratio considerations, among others. We focus on the main three components that form a spectropolarimeter, namely, wavelength discriminators, the devices employed to encode the incoming polarization state into intensity images (polarization modulators), and the sensor technologies used to register them. We consider the instrumental solutions introduced to perform this kind of measurements at different optical wavelengths and from various observing locations, i.e., ground-based, from the stratosphere or near space.

Plant traits related to leaf decomposition processes in arid ecosystems of northern Patagonia Bar Lamas, Marlene Ivonne; Carrera, Analía Lorena; Bertiller, Monica Beatriz Aims: Plants play an important role in ecosystem processes. Functional meaning of trait variation in wide environmental gradients is well known but is scarcely known across narrow gradients. We analyze the variation of morphological, physical and chemical traits of dominant plant species and the potential rates of dry mass loss and N release/immobilization during senesced leaf decomposition of these species across a narrow aridity gradient, and to identify indicative traits useful to set species functional groups sharing decomposition patterns. Methods: We analyzed the variation of morphological, physical and chemical traits (specific leaf area, seed mass, N and soluble phenols in green and senesced leaves, plant height) in dominant plant species at 12 sites across an aridity gradient in northern Patagonia, Argentina. We collected senesced leaves of each plant species at each site and used them to estimate the potential rates of dry mass loss and N release/immobilization from decomposing senesced leaves in a microcosm experiment. We analyzed the variation of plant traits and decomposition rates across the aridity gradient. We grouped plants species according to growth forms (perennial grasses, deciduous shrubs, evergreen shrubs) and different combinations of morpho-physical and chemical traits of green and senesced leaves and compared the potential rates of dry mass loss and N release/immobilization during leaf decomposition among these groups delimited by each grouping criteria. Important Findings: Plant traits did not vary across the aridity gradient. The potential rate of dry mass loss was positively related to aridity, while the potential rate of N release/immobilization did not vary across the gradient. Grouping species by separately morpho-physical and chemical traits resulted in a large overlapping in mean values of decomposition rates among groups. In contrast, plant groupings based on growth forms and those including all morpho-physical and chemical traits of green or senesced leaves yielded groups with differentiated rates of decomposition processes. The two latter groupings clustered species from more than one growth form indicating some overlapping in the rates of decomposition processes among species of different growth forms. Among traits, N concentration in senesced leaves and plant height explained the highest variation in decomposition rates being positively related to potential rates of dry mass loss and N release/immobilization. We concluded that plant groupings based on morpho-physical and chemical traits of either green or senesced leaves may be more powerful to differentiate functional species groups sharing decomposition patterns than the growth form grouping. Moreover, plant height and N concentration in senesced leaves may be considered relevant synthetic functional traits in relation to decomposition processes in narrow aridity gradients.

Role of UV-C irradiation scheme on cell wall disassembly and surface mechanical properties in strawberry fruit Ortiz Araque, Leidy Carolina; Ortiz, Cristian Matias; Darré, Magalí; Rodoni, Luis Maria; Civello, Pedro Marcos; Vicente, Ariel Roberto UV-C treatments have been reported to prevent frmness loss and decay in part by delaying the degradation of fruit structural barriers. The influence of the irradiation regime on wall disassembly has not been determined. We evaluated the influence of single pre-storage and repeated-low dose UV-C treatments on rawberry mechanical properties and cell wall degradation. Ripe strawberry was subjected to Single-Step UV irradiation (4 kJ m-⁠ 2 prior to storage); Two-Step UV irradiation: two 2 kJ m−⁠ 2 treatments after 0 and 4 days at 0 °C and Multi-Step UV irradiation: fve 0.8 kJ m−⁠ 2 UV-C applications every 2 days until day 8 at 0 °C. A non-irradiated group was used as a con trol. During storage we determined the changes in surface mechanical properties, hemicellulose and pectin solubility-β-glucanase-β-glucosidase, (Glcase) α-xylosidase (Xylase), polygalacturonase, (PG); pectinmethylesterase (PME), α-arabinofuranosidase (AFase), and β-galactosidase (β-gal) activities. UV treated berries showed higher surface hardness and resistance to compression and tolerated greater compression distance to tissue failure. Softening was more effectively reduced in fruit receiving Two-Step and Multi-Step irradiations. Though all UV-C treatments transiently decreased PG, PME and Glcase activities, the improved frmness retention found after Two-Step and Multi-Step irradiation was related to the inhibition of Xylase and β-gal. Repeated low dose UV exposure prevented softening by delaying pectin solubilization.

Biocomposites Based on Thermoplastic Starch and Granite Sand Quarry Waste Passaretti, María Gabriela; Ninago, Mario Daniel; Paulo, Cecilia Inés; Petit, Andres; Irassar, Edgardo Fabián; Vega, Daniel Alberto; Villar, Marcelo Armando; Lopez, Olivia Valeria Granite stone is a by-product of the rock crushing manufacturing. An industrial waste in powder form that causes health problems and environmental pollution. Fine particles fraction can be used as a partial replacement of sand in concrete manufacture. In this work, an alternative exploitation of this waste fraction is proposed. Granite sand (GS) with particles mean size of ~1 μm was employed as thermoplastic starch (TPS) filler at different concentrations. Biocomposites were obtained by melt-mixing and thermo-compression, achieving translucent and easy to handle films. A good GS dispersion within the matrix was evidenced by SEM. Mineral presence induced a shift of starch’s melting point to higher values and a better thermal resistance. TPS UV absorption capacity was increased ~90% by GS addition. An increment in TPS Young’s modulus and maximum tensile stress of 5 and 3 times, respectively was observed by adding 5 % w/w GS.

One-Step Immobilization and Stabilization of a Recombinant Enterococcus faecium DBFIQ E36 l-Arabinose Isomerase for d-Tagatose Synthesis de Sousa, Marylane; Melo, Vânia M. M.; Hissa, Denise C.; Manzo, Ricardo Martín; Mammarella, Enrique José; Antunes, André Saraiva Leão Marcelo; García, José L.; Pessela, Benevides C.; Gonçalves, Luciana R. B. A recombinant l-arabinose isomerase from Enterococcus faecium DBFIQ E36 was immobilized onto multifunctional epoxide supports by chemical adsorption and onto a chelate-activated support via polyhistidine-tag, located on the N-terminal (N-His-L-AI) or on the C-terminal (C-His-L-AI) sequence, followed by covalent bonding between the enzyme and the support. The results were compared to reversible L-AI immobilization by adsorption onto charged agarose supports with improved stability. All the derivatives presented immobilization yields of above 75%. The ionic interaction established between agarose gels containing monoaminoethyl-N-aminoethyl structures (MANAE) and the enzyme was the most suitable strategy for L-AI immobilization in comparison to the chelate-activated agarose. In addition, the immobilized biocatalysts by ionic interaction in MANAE showed to be the most stable, retaining up to 100% of enzyme activity for 60 min at 60 °C and with Km values of 28 and 218 mM for MANAE-N-His-L-AI and MANAE-C-His-L-AI, respectively.