Matching in vitro bioaccessibility of polyphenols and antioxidant capacity of soluble coffee by Boosted Regression Trees Podio, Natalia Soledad; López Froilán, Rebeca; Ramirez Moreno, Esther; Bertrand, Lidwina; Baroni, María Verónica; Pérez Rodríguez, María L.; Sánchez Mata, María Cortes; Wunderlin, Daniel A. The aim of this study was to evaluate changes in polyphenol profile and antioxidant capacity of five soluble coffees throughout a simulated gastro-intestinal digestion, including absorption through a dialysis membrane. Our results demonstrate that both polyphenol content and antioxidant capacity were characteristic for each type of studied coffee, showing a drop after dialysis. Twenty-seven compounds were identified in coffee by HPLC-MS, while only 14 of them were found after dialysis. Green+roasted coffee blend and chicory+coffee blend showed the highest and lowest content of polyphenols and antioxidant capacity before in vitro digestion and after dialysis, respectively. Canonical correlation analysis showed significant correlation between the antioxidant capacity and the polyphenol profile before digestion and after dialysis. Furthermore, boosted regression trees analysis (BRT) showed that only four polyphenol compounds (5-p-coumaroylquinic acid, quinic acid, coumaroyl tryptophan conjugated, and 5-O-caffeoylquinic acid) appear to be the most relevant to explain the antioxidant capacity after dialysis, these compounds being the most bioaccessible after dialysis. To our knowledge, this is the first report matching the antioxidant capacity of foods with the polyphenol profile by BRT, which opens an interesting method of analysis for future reports on the antioxidant capacity of foods.

La palomita escamada (columbina squammata) ocupa pequeños claros de desmontes en el Chaco húmedo Gandoy, Facundo Ariel; Brissón Egli, Federico; Gorleri, Fabricio Carlos; Castillo, Leandro; Zalazar, Sofia La Palomita Escamada (Columbina squammata) es un columbiforme que se distribuye únicamente en Sudamérica y posee dos subespecies alopátricas: C. s. ridgwayi al norte del subcontinente, y C. s. squammata en el sudeste de Brasil, Paraguay, este de Bolivia y norte de Argentina (Estela et al. 2005, Rodríguez-Mata et al. 2006). En este último país se la ha reportado solo en la provincia de Misiones (Partridge 1961, Narosky & Yzurieta 2003, Rodríguez-Mata et al. 2006, Krauczuk 2008, Bodrati et al. 2010). A continuación presentamos nuevos registros que expanden la distribución conocida a las provincias de Formosa, Corrientes y Chaco.

Multiclass compatible sample preparation for UHPLC-MS/MS determination of aflatoxin M1 in raw milk Michlig, Nicolás; Repetti, María Rosa; Chiericatti, Carolina; García, Silvia R.; Gaggiotti, Mónica; Basilico, Juan Carlos; Beldomenico, Horacio Ramon A sample preparation method for aflatoxin M1 (AFM1) determination in raw milk was optimized following the quick, easy, cheap, effective, rugged and safe (QuEChERS) strategy, as an alternative to the classic immunoaffinity column clean-up (IAC). The method was adapted to address the complexity of the milk matrix, and to be suitable for final determination by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS). This approach proved also to be compatible with the simultaneous extraction of pesticide residues and other contaminants (mycotoxins). Regarding AFM1, satisfactory linearity was achieved and appropriate sensitivity was maintained, using matrix-matched calibration to compensate for the heavy ion suppression. The accuracy and precision, which were determined through recovery studies, were 70–95 %, with the relative standard deviation below 15 % in all of the cases. The limit of detection (LOD, 0.002 μg L−1) and limit of quantification (0.007 μg L−1) are compatible with current worldwide regulations (maximum levels of 0.5 and 0.05 μg L−1). The procedure was applied to samples that were naturally contaminated with a range of AFM1 at LOQ–0.187 μg L−1, with comparable results to IAC clean-up, which was employed as a reference method. Therefore, AFM1 determination in raw milk by UHPLC–MS/MS detection through the present QuEChERS extraction constitutes a reliable alternative to IAC clean-up and exhibits advantages related to cost, accessibility of materials and simplicity of operation.

An improvement of the sensitivity of GPS radio occultation data to detect gravity waves through observational and modeling factors Alexander, Pedro Manfredo; de la Torre, Alejandro; Hierro, Rodrigo Federico; Llamedo Soria, Pablo Martin There is a mid-latitude region to the East of the Andes Range in the Southern Hemisphere that exhibits ideal conditions for the generation of gravity waves (GW) by topography mainly during winter. The configuration favors the generation of wavefronts that are parallel to the North–South direction. Global Positioning System (GPS) radio occultation (RO) retrievals from the COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) mission exhibit in a large proportion of the soundings an orientation which should be favorable to the detection of these wavefronts. We try to verify if this GW activity surplus on the East with respect to the West in the studied zone in winter emerges clearly in the GPS RO data between years 2007 and 2012. We argue that the orientation of the soundings but also the mathematical model selected to represent the GW energy distribution can affect the possibility of detecting the signatures of the waves. In particular, we explore a new interpretation of the GW energy distribution observed by GPS RO at the lowest values, as they stay below the precision limit of the technique. We suggest to replace that part of the measured distribution by an exponential curve that in general suits the trend of all the other observed energies. In following this alternative it is shown that the calculated mountain wave activity in the studied sector is now even more clearly larger in the East than in the West during winter. Finally, we consider that energy distributions observed with any measurement technique should in general not be considered as the solely contribution from waves, as also other variable phenomena may be adding to the final outcome.

Compromiso conductual y desafección con las actividades escolares: Explorando un modelo de facilitadores motivacionales y resultados de rendimiento; Behavioral engagement and disaffection in school activities: Exploring a model of motivational facilitators and performance outcomes González, Antonio; Paoloni, Paola Veronica Rita; Donolo, Danilo Silvio; Rinaudo, María Cristina Investigaciones previas han mostrado que el control percibido, el valor de la tarea, el compromiso conductual y la desafección son determinantes personales del rendimiento académico. Sin embargo, pocas investigaciones han examinado simultáneamente estos constructos en educación secundaria. El presente estudio analizó las relaciones estructurales entre estas variables y el papel del compromiso y la desafección como mediadores de los efectos del control y el valor sobre el rendimiento. Los participantes fueron 446 estudiantes (51.3% chicas) con edades comprendidas entre 12 y 16 años que asistían a seis colegios de educación secundaria obligatoria (de 7º a 10º cursos; de 1º a 4º de ESO). Las variables se evaluaron a lo largo de nueve meses. Los resultados de los modelos de ecuaciones estructurales confirmaron las hipótesis: el control y el valor predijeron significativamente el compromiso, la desafección y el rendimiento; el compromiso y la desafección predijeron el rendimiento y mediaron parcialmente los efectos del control y el valor sobre el rendimiento. Se concluye discutiendo las implicaciones para la teoría y la práctica psicoeducativa.; Previous research has shown that perceived control, task value, behavioral engagement and disaffection are personal determinants of academic performance. However, little research has simultaneously examined these constructs in secondary education. The present study analyzed the structural relationships between these variables and the role of engagement and disaffection as mediators of control and value on performance. Participants were 446 students (51.3% girls) ranging in age from 12 to 16 years attending six Spanish compulsory secondary schools (from 7th to 10th grades). The variables were assessed over a nine-month period. Structural equation models results confirmed the hypotheses: control and value significantly predicted engagement, disaffection, and performance; engagement and disaffection predicted performance and partially mediated the effects from control and value on performance. Implications for psycho-educational theory and practice are discussed.

Carcinoma neuroendocrino de timo con enfermedad de pompe del adulto; Thymic neuroendocrine carcinoma with Pompe's disease of the adult Aruj, Patricia K.; Rausch, Silvia; de Vito, Eduardo La enfermedad de Pompe (glucogenosis tipo II) es una enfermedad de depósito lisosomal, autosómica recesiva causada por una deficiencia de ácido alfa-glucosidasa. Los tumores neuroendocrinos tímicos son neoplasias primarias con diferenciación neuroendocrina que generalmente se presentan como una masa en el mediastino anterior. Ambas enfermedades se consideran raras en sí mismas. En nuestro conocimiento, la enfermedad de Pompe y un tumor neuroendocrino del timo en el mismo paciente no ha sido antes comunicada. No pudimos encontrar la plausibilidad biológica entre ambas enfermedades. Se necesitan más estudios para confirmar el hallazgo y para aumentar aún más nuestra comprensión de esta asociación. Los datos clínicos de los estudios epidemiológicos, los informes de casos, las series de casos y los pequeños ensayos clínicos abiertos o controlados pueden definir tanto la plausibilidad clínica como la causalidad entre las dos enfermedades.; Pompe disease (glycogenosis type II) is an inherited autosomal recessive lysosomal storage disease caused by a deficiency of acid alpha-glucosidase. Thymic neuroendocrine tumors, are primary thymic neoplasms with neuroendocrine differentiation that generally present as a mass within the anterior mediastinum. Both diseases are considered rare. To our knowledge the co-existence of Pompe disease and thymic neuroendocrine tumor in the same patient has not been previously reported. We could not find biological plausibility between both diseases. Further studies are needed to confirm the finding and to further increase our understanding of this association. Clinical data from epidemiological studies, case reports, case series and small formal open or controlled clinical trials may define both clinical plausibility and causality between the two conditions.

Hypoxia-induced nitric oxide release by luminal cells stimulates proliferation and uPA secretion of myoepithelial cells in a bicellular murine mammary tumor Krasnapolski, Martin Alejandro; Lodillinsky, Catalina; Bal, Elisa Dora; Eijan, Ana Maria Introduction: LM38 murine mammary adenocarcinoma model is formed by LM38-LP (myoepithelial and luminal), LM38-HP (luminal) and LM38-D2 (myoepithelial) cell lines. In a previous work, we had shown that LM38-HP and LM38-D2 cell lines are less malignant than the bicellular LM38-LP cell line. Purpose: To study the role of nitric oxide (NO) as one of the mediators of functional interactions between malignant luminal and myoepithelial cells. Methods and results: Using immunohistochemistry, in vivo iNOS expression was only detected in the luminal cells of bicellular LM38-LP and most cells of LM38-HP tumors. In cobalt-induced pseudohypoxia, LM38-LP and LM38-HP cell lines significantly increased HIF-1α and iNOS expression (Western blotting) and therefore NO production (Griess method). This increase was inhibited by the iNOS inhibitor 1400 W. On the other side, NO was not detectable in LM38-D2 cells either in basal or in pseudohypoxia. In addition, pseudohypoxia increased urokinase-type plasminogen activator (uPA) secretion by LM38-LP and LM38-HP cells and migration in the LM38-LP cell line, without modulating these properties in LM38-D2 cells (radial caseinolysis). The NO donor DETA/NONOate (500 μM) was able to increase uPA secretion and in vitro growth of LM38-D2. In agreement, 1400 W prevented in vivo growth of the myoepithelial LM38-D2 cells. Conclusions: Hypoxia leads to an enhanced NO production by the luminal component, through HIF-1α and iNOS, which can stimulate myoepithelial cell proliferation and uPA secretion. In these new conditions, myoepithelial cells might act as an invasive forefront generating gaps that could help luminal cells to escape from the primary tumor.

Production of virus-free plants of Lilium spp. from bulbs obtained in vitro and ex vitro Chinestra, Silvia Carolina; Curvetto, Nestor Raul; Marinangeli, Pablo Alejandro Lilium tissue culture is used for mass propagation of elite material as well as for obtaining virus-free plants. The aim of the present study was to evaluate the effectiveness of meristem tip culture from microbulbs obtained in vitro and from bulblets obtained via scaling macropropagation – either with or without thermotherapy and chemotherapy treatments applied before meristem tip culture – to obtain virus-free Lilium spp. plants. To this end, microshoot regeneration from meristematic tips was first tested and two diagnostic techniques were compared after meristem tip culture treatment. Different alternatives were assayed in several Lilium hybrids to obtain virus-free plants. Effective virus elimination was possible using meristematic tips extracted from bulblets produced ex vitro by scaling, a procedure that has not been previously reported in Lilium. The number of virus-free plants obtained, which depended on the genotype as well as on the virus present in the original material, reached ∼100% via meristem tip culture with or without pre-thermotherapy treatment at 35 °C. Meristem tip culture produced 100% of LMoV-free plants in Lilium longiflorum ‘Snow Queen’ and LA hybrid ‘Lacorno’, also CMV-free plants in Asiatic hybrid ‘Navona’ and LA hybrid ‘Fangio’, and LSV-free plants in LA ‘Royal Respect’. The LSV infection rate decreased in Asiatic hybrid ‘Visconti’ when thermotherapy was applied ex vitro before meristem tip culture. Chemotherapy applied during in vitro bulb differentiation prior to meristem tip culture led to a complete elimination of LSV in the LO hybrid ‘Triumphator’. Ex vitro chemotherapy was ineffective in virus elimination even when applied at high concentrations.

Single point mutations in the helicase domain of the NS3 protein enhance dengue virus replicative capacity in human monocyte-derived dendritic cells and circumvent the type I interferon response Silveira, G. F.; Strottmann, D. M.; de Borba, Luana; Mansur, D. S.; Zanchin, N. I. T.; Bordignon, J.; Duarte dos Santos, C.N. Dengue is the most prevalent arboviral disease worldwide. The outcome of the infection is determined by the interplay of viral and host factors. In the present study, we evaluated the cellular response of human monocyte-derived DCs (mdDCs) infected with recombinant dengue virus type 1 (DV1) strains carrying a single point mutation in the NS3hel protein (L435S or L480S). Both mutated viruses infect and replicate more efficiently and produce more viral progeny in infected mdDCs compared with the parental, non-mutated virus (vBACDV1). Additionally, global gene expression analysis using cDNA microarrays revealed that the mutated DVs induce the up-regulation of the interferon (IFN) signalling and pattern recognition receptor (PRR) canonical pathways in mdDCs. Pronounced production of type I IFN were detected specifically in mdDCs infected with DV1-NS3hel-mutated virus compared with mdDCs infected with the parental virus. In addition, we showed that the type I IFN produced by mdDCs is able to reduce DV1 infection rates, suggesting that cytokine function is effective but not sufficient to mediate viral clearance of DV1-NS3hel-mutated strains. Our results demonstrate that single point mutations in subdomain 2 have important implications for adenosine triphosphatase (ATPase) activity of DV1-NS3hel. Although a direct functional connection between the increased ATPase activity and viral replication still requires further studies, these mutations speed up viral RNA replication and are sufficient to enhance viral replicative capacity in human primary cell infection and circumvent type I IFN activity. This information may have particular relevance for attenuated vaccine protocols designed for DV.

Evolution of the Chos Malal and Agrio fold and thrust belts, Andes of Neuquén: insights from structural analysis and apatite fission track dating Rojas Vera, Emilio Agustin; Mescua, Jose Francisco; Folguera Telichevsky, Andres; Becker, T. P.; Sagripanti, Lucía; Fennell, Lucas Martín; Orts, Darío Leandro; Ramos, Victor Alberto The Chos Malal and Agrio fold and thrust belts are located in the western part of the Neuquén basin, an Andean retroarc basin of central-western Argentina. Both belts show evidence of tectonic inversion at the western part during Late Cretaceous times. The eastern part is dominated by late Miocene deformation which also partially reactivated the western structures. This work focuses on the study of the regional structure and the deformational event that shaped the relief of this part of the Andes. Based on new field work and structural data and previously published works a detailed map of the central part of the Neuquén basin is presented. Three regional structural cross sections were surveyed and balanced using the 2d Move™ software. In order to define a more accurate uplift history, new apatite fission track analyses were carried on selected structures. These data was used for new thermal history modeling of the inner part of the Agrio and Chos Malal fold and thrust belts. The results of the fission track analyses improve the knowledge of how these fold and thrust belts have grown trough time. Two main deformational events are defined in Late Cretaceous to Paleocene and Late Miocene times. Based on this regional structural analysis and the fission track data the precise location of the orogenic front for the Late Cretaceous-Paleocene times is reconstructed and it is proposed a structural evolution of this segment of the Andes. This new exhumation data show how the Late Cretaceous to Paleocene event was a continuous and uninterrupted deformational event.

Effects of Saturn's magnetospheric dynamics on Titan's ionosphere Edberg, N. J. T.; Andrews, D. J.; Bertucci, Cesar; Gurnett, D. A.; Holmberg, M. K. G.; Jackman, C. M.; Kurth, W. S.; Menietti, J. D.; Opgenoorth, H. J.; Shebanits, O.; Vigren, E.; Wahlund, J. E. We use the Cassini Radio and Plasma Wave Science/Langmuir probe measurements of the electron density from the first 110 flybys of Titan to study how Saturn´s magnetosphere influences Titan´s ionosphere. The data is first corrected for biased sampling due to varying solar zenith angle and solar energy flux (solar cycle effects). We then present results showing that the electron density in Titan´s ionosphere, in the altitude range 1600-2400 km, is increased by about a factor of 2.5 when Titan is located on the nightside of Saturn (Saturn local time (SLT) 21-03 h) compared to when on the dayside (SLT 09-15 h). For lower altitudes (1100-1600 km) the main dividing factor for the ionospheric density is the ambient magnetospheric conditions. When Titan is located in the magnetospheric current sheet, the electron density in Titan´s ionosphere is about a factor of 1.4 higher compared to when Titan is located in the magnetospheric lobes. The factor of 1.4 increase in between sheet and lobe flybys is interpreted as an effect of increased particle impact ionization from 200 eV sheet electrons. The factor of 2.5 increase in electron density between flybys on Saturn´s nightside and dayside is suggested to be an effect of the pressure balance between thermal plus magnetic pressure in Titan´s ionosphere against the dynamic pressure and energetic particle pressure in Saturn´s magnetosphere.

Evaluación de un curso de formación docente continua sobre TIC: una propuesta destinada a profesores universitarios de carreras científicas y tecnológicas; Evaluation of a course of continuous teacher training related to Ict: a proposal for faculty members of science and technology careers Garcia, Leticia; Occelli, Maricel; Quse, Ligia del Carmen Maria; Masullo, Marina; Biber, Priscila El trabajo presenta una investigación acerca de una experiencia de formación docente continua sobre TIC en la cual participaron 24 profesores universitarios de ciencia y tecnología de la ciudad de Córdoba, Argentina. La propuesta se centró en fundamentos tecnológicos, pedagógicodidácticos y contextuales y tuvo tres ejes conceptuales, la comunicación, el trabajo colaborativo y la evaluación en ambientes virtuales de aprendizaje. Los profesores participantes analizaron las fortalezas y debilidades de sus aulas virtuales y diseñaron contenidos y actividades a través del trabajo conjunto entre pares y expertos. Los resultados indican que los docentes parten de prácticas tradicionales de enseñanza y luego de la instancia de formación logran mejorar diversos aspectos de sus aulas virtuales, especialmente en lo que respecta a la evaluación continua de los aprendizajes.

Susceptibility to β-lactams and quinolones of Enterobacteriaceae isolated from urinary tract infections in outpatients Marchisio, Martín; Porto, Ayelen Patricia; Joris, Romina; Rico, Marina; Baroni, María R.; Di Conza, José Alejandro The antibiotic susceptibility profile was evaluated in 71 Enterobacteriaceae isolates obtained from outpatient urine cultures in July 2010 from two health institutions in Santa Fe, Argentina. The highest rates of antibiotic resistance were observed for ampicillin (AMP) (69%), trimethoprim/sulfamethoxazole (TMS) (33%), and ciprofloxacin (CIP) (25%). Meanwhile, 21% of the isolates were resistant to three or more tested antibiotics families. Thirty integron-containing bacteria (42.3%) were detected, and a strong association with TMS resistance was found. Third generation cephalosporin resistance was detected in only one Escherichia coli isolate, and it was characterized as a blaCMY-2 carrier. No plasmid-mediated quinolone resistance (PMQR) was found. Resistance to fluoroquinolone in the isolates was due to alterations in QRDR regions. Two mutations in GyrA (S83L, D87N) and one in ParC (S80I) were observed in all CIP-resistant E. coli. It was determined to be the main phylogenetic groups in E. coli isolates. Minimum Inhibitory Concentration (MIC) values against nalidixic acid (NAL), levofloxacin (LEV), and CIP were determined for 63 uropathogenic E. coli isolates as MIC50 of 4 μg/mL, 0.03125 μg/mL, and 0.03125 μg/mL, respectively, while the MIC90 values of the antibiotics were determined as 1024 μg/mL, 64 μg/mL, and 16 μg/mL, respectively. An association between the phylogenetic groups, A and B1 with fluoroquinolone resistance was observed. These results point to the importance of awareness of the potential risk associated with empirical treatment with both the families of antibiotics.

Absolute configuration assignment of an unusual homoisoflavanone from Polygonum ferrugineum using a combination of chiroptical methods Batista Jr., João Marcos; Wang, Bo; Castelli, Maria Victoria; Blanch, Ewan W.; López, Silvia Noelí The absolute configuration of the homoisoflavanone 5,7-dihydroxy-6-methoxy-3-(9-hydroxy-phenylmethyl)-chroman-4-one (1), found in Polygonum species, has been determined as 3R,9R by using a combination of electronic and vibrational chiroptical spectroscopic methods. The experimental spectra were interpreted with the aid of density functional theory calculations. The risks of relying upon a single method for stereochemical characterization of natural products are discussed.

Germinación y emergencia de Megathyrsus Maximus Var.Maximus; Germination and Emergence of Megathyrsus maximus var. maximus Cabrera, Debora Carina; Sobrero, M. T.; Chaila, S.; Pece, M. Se estudió la germinación de semillas de Megathyrsus maximus al exponerlas a altas temperaturas y el efecto de diferentes profundidades de siembra y cantidades de residuos de cosecha en la emergencia de las plántulas. En laboratorio, se determinó la germinación y biomasa de semillas con y sin glumas y glumelas, expuestas a 0, 40, 60, 80 y 100 oC durante cinco minutos. Se realizaron dos experimentos en invernáculo para evaluar la emergencia de la maleza, primero a diferentes profundidades de siembra: 0, 0.5, 1, 2, 3, 4, 5, 7 y 8 cm. Posteriormente, se evaluó emergencia con diferentes cantidades de residuos de cosecha: 0, 5, 8, 11, 13, 15 y 18 t ha-1. Los resultados de los ensayos de temperatura se analizaron mediante análisis de covarianza y los datos de los ensayos de invernáculo mediante regresión. Los máximos porcentajes de germinación para semillas con y sin glumas y glumelas se obtuvieron a 40 oC y fueron del 35 y 48%, respectivamente; los mínimos valores se registraron a los 80 oC y fueron del 7 y 28%, respectivamente. La profundidad de siembra afectó la emergencia: un 51% se registró en el testigo, valor que disminuyó al 23,3% a los 7 cm y a 0% a los 8 cm. Los residuos de cosecha también afectaron la emergencia: con 0 a 18 t ha-1, esta disminuyó del 64,8 al 0%. Puede concluirse que las estrategias implementadas en el manejo del cultivo de caña de azúcar afectarán la germinación y emergencia de M. maximus.; This work aimed to study the germination of Megathyrsus maximus seeds when exposed to high temperatures, as well as to evaluate the effects of different seed planting depths and sugarcane crop residue amounts on weed emergence. In the laboratory, germination and biomass of seeds with and without glumes were determined when exposed to 0, 40, 60, 80 and 100 oC, for five minutes. Two experiments were performed in the greenhouse to assess the emergence rate in relation to different weed seed planting depths (0, 0.5, 1, 2, 3, 4, 5, 7 and 8 cm) on the one hand, and in relation to different sugarcane crop residue quantities (0.5, 8, 11, 13, 15 and 18 t ha-1) on the other. Temperature tests were analyzed by means of covariance analysis, whereas greenhouse tests were analyzed with regression. The highest germination percentages for seeds with and without glumes were 48 and 35%, respectively, and they were obtained at 40 oC. The lowest values were 28 and 7% for seeds with and without glumes, respectively, and they were obtained at 80 oC. Seed planting depth had a negative effect on weed emergence: the control led to 51% emergence, which dropped to 23.3% at 7 cm and eventually to zero at 8.0 cm. Crop residues had a negative effect on emergence as well: when residue quantities ranged from 0 to 18 t ha-1, emergence decreased from 64.8 to 0%.Thus we can conclude that sugarcane management strategies affect M. maximus germination and emergence.

Assessment of alternative sources of seaweed polysaccharides in Argentina: potentials of the agarophyte Gelidium crinale (Hare ex Turner) Gaillon (Rhodophyta, Gelidiales) Croce, Maria Emilia; Villar, Marcelo Armando; Parodi, Elisa Rosalia The phycocolloids industry in Argentina has been based on the importation of non-native species and the exploitation of natural populations of Gracilaria, which are currently declining. This study was carried out to evaluate the potential of Gelidium crinale as an unexploited source of agar in this country. The yield and composition of polysaccharides extracted from G. crinale, as well as the growth potential of this species were studied. In vitro cultures of apical sections were carried out; relative growth rates (RGR) and data were analyzed through repeated measurements. Explants rapidly duplicated their initial size, producing numerous proliferations and achieving structural complexity. RGR of explants, primary proliferations, and secondary proliferations were high and similar. Polysaccharide extraction was done under three conditions: acid pre-extraction treatment + pressure boiled (AP), water pre-extraction treatment + pressure boiled (WP), and water pre-extraction treatment + boiled (WB). Polysaccharides were characterized through infrared spectroscopy, X-ray fluorescence, thermogravimetric, and elemental analysis. Polysaccharides obtained corresponded to the agar-type, and showed high similarity to commercial agar samples, with low sulfate and methyl contents. Higher yields were obtained with pressure extractions; however, acid treatment did not increase the amount of extracted biopolymers. Their degradation occurred in the range 250–400 °C. Polysaccharides obtained under AP conditions had a degradation curve similar to food-grade agar-agar, whereas degradation curves of polysaccharides obtained without acid treatment were similar to biotechnology-grade agar-agar. According to the results, G. crinale from Anegada Bay produces a high-quality agar to be considered for the Argentinean agar industry; however, micropropagation techniques would be indispensable to increase its bioavailability.

Cultural patterns of firewood use as a tool for conservation: a study of multiple perceptions in a semiarid region of Cordoba Martinez, Gustavo Javier The paper analyzes local perceptions and practices related to the quality, extraction, and use of fuels firewood by the inhabitants of two protected areas. Our working model assumes the existence of patterns of preference, use and acquisition of firewood, depending on the social actors involved, and their perceptions. Our research developed through: the making of a reference collection and the applicationand of in-depth interviews and semi-structured surveys. We identified the most frequently used species and those with the greatest number of uses. The presence of patterns in the provisioning of energy source, and of firewood gathering and use, were identified in different actors. Through the application of a PCA analysis, and the study of native categories, patterning in the grouping of species was established, according to the local firewood classification. The latter relate to differences in the ease of ignition, in the durability and temperature of the flame and/or embers and the amount and type of smoke or ash produced. On the basis of ecological and perceptual information, a ranking of local priorities for the conservation of woody species is proposed. Finally, we discuss the relevance of sociocultural patterns of local perceptions of firewood use for conservation.

La vejez como problema histórico: Una agenda de investigación Otero, Hernan Gustavo La historia de la vejez se ha constituido desde los años ochenta como un campo de indagación relevante, tanto por el creciente interés de su objeto de estudio en la agenda pública como por ubicarse en la encrucijada de la demografía histórica, la historia de la población y la historia social en general. Partiendo de esta constatación, el texto analiza, en primer lugar, las múltiples dificultades teóricas y metodológicas del estudio histórico de ese colectivo etario. En segundo término, recorre la principal producción historiográfica existente con el fin de proponer una agenda de investigación, atenta a las fuentes y problemas específicos del caso argentino.; The history of old age has become a field of relevant research since the eighties, both by the growing interest of its subject matter on the public agenda and by its location at the crossroads of historical demography, population history, and social history in the main. With this in mind, the text analyzes firstly the multiple theoretical and methodological difficulties of historical study of that age group. Secondly, it scours the main existing historiographical production in order to propose a research agenda, mindful of the sources and specific problems of the Argentine case.

Ingresar al "Estado". Marco decisional, actores e intereses en los procesos de ingreso de personal en la Administración Pública correntina Ojeda, Valeria Patricia Este artículo reúne parte de los resultados de una tesis doctoral recientemente defendida para el Doctorado en Ciencias Sociales de la Universidad Nacional de Cuyo, denominada ?Configuración de intereses en la Gestión de la Fuerza de Trabajo. Implicancias políticas e institucionales en la Administración Pública de Corrientes (1983-2012)?. El problema que aquí abordamos se circunscribe a las características que reúne el proceso de ingreso al empleo público, cuando el marco institucional para esta función se encuentra desactivado. Nuestro objetivo es entonces reconstruir la configuración del proceso de ingreso y conocer algunas de las estrategias que desarrollan los actores (trabajadores estatales-línea de decisión política) a fin de cumplimentar sus intereses. Asimismo revisar cómo se articulan las decisiones en torno a tales estrategias. Para la reconstrucción de estas formas y maneras de acceder al empleo (o de obtener personal) trabajamos a partir de entrevistas en profundidad realizadas a agentes estatales (mandos medios con responsabilidades de gestión de personal) de tres ministerios de la Administración Pública Provincial del nivel central, seleccionados a partir de un muestreo intencional. El tamaño de la muestra fue definido a través del criterio de saturación teórica. Recordemos que el marco institucional que regula el ingreso al Estado provincial correntino se encuentra previsto en la Ley 4067, Ley de Servicio Civil de la Provincia. Esta ley, sancionada en 1986 durante el gobierno de José Antonio Romero Feris, considera de manera amplia los derechos y obligaciones tanto de los trabajadores como del Estado en su rol patronal: define también la naturaleza de las relaciones de trabajo establecidas, un sistema escalafonario, los procesos relativos a la movilidad (carrera) de los trabajadores, un régimen de licencias y franquicias, como aspectos más sobresalientes. Sin embargo, como hemos podido comprobar en la tesis doctoral, gran parte del articulado de la Ley 4067 se encuentra discutido. Ya sea por ausencia de reglamentación, por solapamiento con otras leyes laborales provinciales (por ejemplo con la Ley de Sueldos y Remuneraciones 3801), o simplemente por desatención o incumplimiento, el sistema de concurso se encuentra desactivado. Esta inhabilitación responde a una serie de decisiones a nivel gubernamental, que se fueron replicando a lo largo de los casi 30 años que abordó nuestro trabajo. Es decir: los diferentes gobiernos consideraron que el acceso al empleo de los trabajadores se realice por fuera del sistema de concursos establecido por la Ley 4067 (excepto en tres ocasiones). Tenemos por lo tanto diversos agentes que conocen las oportunidades que le brinda la configuración del proceso de ingreso, y que, en función de las mismas, activarán estrategias para lograr objetivos de su interés. Pero estos objetivos no serán iguales para todos ellos: se modificará en función del rol que cumplan. De esta forma se entretejerá una trama de intereses que calificará no solo la función de empleo sino también el resto de las funciones de GFT.

Functional nicotinic acetylcholine receptor reconstitution in Au(111)-supported Thiolipid Monolayers Pissinis, Diego Ezequiel; Diaz, Carolina; Maza, Eliana María; Bonini, Ida Clara; Barrantes, Francisco Jose; Salvarezza, Roberto Carlos; Schilardi, Patricia Laura The insertion and function of the muscle-type nicotinic acetylcholine receptor (nAChR) in Au(111)- supported thiolipid self-assembled monolayers have been studied by atomic force microscopy (AFM), surface plasmon resonance (SPR), and electrochemical techniques. It was possible for the first time to resolve the supramolecular arrangement of the protein spontaneously inserted in a thiolipid monolayer in an aqueous solution. Geometric supramolecular arrays of nAChRs were observed, most commonly in a triangular form compatible with three nAChR dimers of ∼20 nm each. Addition of the full agonist carbamoylcholine activated and opened the nAChR ion channel, as revealed by the increase in capacitance relative to that of the nAChR?thiolipid system under basal conditions. Thus, the self-assembled system appears to be a viable biomimetic model to measure ionic conductance mediated by ion-gated ion channels under different experimental conditions, with potential applications in biotechnology and pharmacology