An Improved Control Strategy for Hybrid Wind Farms Leon, Enrique Andres; Mauricio, Juan Manuel; Gomez-Exposito, Antonio; Solsona, Jorge Alberto This paper addresses the control requirements of hybrid wind farms, comprising a relatively large number of conventional Induction Machines (IM) along with one or very few Permanent Magnet Synchronous Machines (PMSM), capable of compensating the reactive power demanded by the IMs during faulty conditions as well as attenuating the active power variations due to wind gusts. Based on the superposition theorem and the feedback linearization technique, a controller is designed to independently regulate the positive and negative sequence currents of the PMSM Voltage Source Converters (VSC), overcoming several drawbacks of existing approaches in the presence of unbalanced voltages. In the proposed scheme, the grid-side VSC currents are controlled in order to improve the ride-through capability of IMs, so that the whole wind farm can fulfill demanding grid codes in absence of extra equipment, such as STATCOMs. As shownby the test results, combining IM-based wind farms with PMSMs accomplishes several relevant goals: delivering the reactive power consumption of the IMs, increasing the rated active power of the installation and smoothing mechanical power oscillations.

El Plan del 80 en Santa Fe: regionalización tardía ante la suburbanización inminente Rausch, Gisela Ariana Se intenta una aproximación al Plan Urbano de 1980 de la ciudad de Santa Fe, el cual puede ubicarse dentro de la serie de planes con voluntad de regionalización, que tuvieron lugar en parte de Argentina entre las décadas del 40 y el 60. De publicación tardía, durante el gobierno de facto de 1976-1983, el Plan se alineaba con lo que se dio en llamar planificación integral. El abordaje del Plan tiene como objetivo principal volver la mirada hacia una herramienta de actuación urbana en la que por primera vez en la historia urbanística local se menciona la ocupación de las áreas periféricas de la ciudad. Cuestión que en los últimos años, frente el desborde suburbano que muchas ciudades intermedias argentinas han sufrido a partir de los 70, y en particular, frente al problema hídrico recurrente en Santa Fe, por la ocupación del valle del Paraná, continúa en mesa de debate.

Dieta de Lontra longicaudis (Carnivora, Mustelidae) en el Parque Nacional El Rey (Salta, Argentina) y su comparación con otras poblaciones de la cuenca del Paraná Chemes, Silvina Beatriz; Giraudo, Alejandro Raul; Gil Carbó, Guillermo Se analizó la dieta de Lontra longicaudis en el Parque Nacional El Rey, en la eco-región de las Yungas, noroeste argentino. Se compararon estos datos con los de poblaciones previamente estudiadas en la laguna Iberá (Esteros del Iberá) y en el río Iguazú (Selva paranaense) en el nordeste argentino. Se analizaron 130 heces colectadas en 37 sitios evaluando porcentaje de ocurrencia, frecuencia relativa, importancia relativa porcentual y diversidad de Levins. Se comparó con otras poblaciones mediante el índice de similitud porcentual, re-muestreo por bootstrap y análisis no paramétricos. De un total de 623 presas, Peces, Insectos y Crustáceos fueron más frecuentes que Anfibios, Moluscos, Reptiles y Mamíferos. La mayoría de las presas fueron organismos bentónicos. Nuestros resultados fueron más similares a uno de los estudios del Iberá. Otros dos estudios, del Iberá y del Iguazú, publicados por el mismo autor, fueron más semejantes entre sí. La adaptabilidad trófica de L. longicaudis a diferencias en disponibilidad y variación temporal de las presas o los sesgos metodológicos entre autores, podrían ser causas de las diferencias en las dietas de las poblaciones estudiadas en la cuenca del Paraná.

Orthogonally additive holomorphic functions of bounded type over C(K) Carando, Daniel Germán; Lassalle, Silvia Beatriz; Zalduendo, Ignacio Martin It is known that all k-homogeneous orthogonally additive polynomials P over C(K) are of the form P(x)= ∫Kxkdμ. Thus, x → xk factors all orthogonally additive polynomials through some linear form μ. We show that no such linearization is possible without homogeneity. However, we also show that every orthogonally additive holomorphic function of bounded type f over C(K) is of the form f(x)=∫Kh(x)dμ for some μ and holomorphic h : C (K) → L1(μ) of bounded type.

Chemoprophylactic activity of flubendazole in cystic echinococcosis Ceballos, Laura; Elissondo, María Celina; Sanchez Bruni, Sergio Fabian; Confalonieri, Alejandra; Denegri, Guillermo Maria; Alvarez, Luis Ignacio; Lanusse, Carlos Edmundo Background: Cystic echinococcosis (CE) is an important public health problem worldwide. Flubendazole, administered in tablets, has shown poor in vivo efficacy against CE in humans. However, flubendazole prepared as a solution caused a marked reduction in hydatid cysts developed in mice. The goal of the current work was to compare the chemoprophylactic effect of flubendazole formulated either as a hydroxypropyl-β-cyclodextrin solution or as a carboxymethylcellulose suspension in secondary CE in mice. Methods: Balb/C mice were infected with Echinococcus granulosus protoscoleces. One day after infection, the animals were allocated into 3 different experimental groups: unmedicated control and treated at the time point of infection with flubendazole either prepared as a solution or suspension given twice a day during 15 days. Six months after infection, the animals were sacrificed to collect and weight parasitic cysts. Cyst samples recovered from infected mice of each experimental group were prepared for both scanning and transmission electron microscopy. Results: Both flubendazole formul tions induced a significant reduction in cyst weight compared to the cysts recovered from the unmedicated control animals. Both formulations showed similar flubendazole-induced ultrastructural morphological changes. Conclusion: Flubendazole offers a great potential to become a drug of choice in the preventive treatment of cystic echinococcosis.

Total ozone and equatorial zonal wind Zossi Artigas, Marta Maria; Fernandez de Campra, Patricia Spatial correlations between total column ozone observed by TOMS and equatorial zonal winds from 1979 to 2003 have been assessed. Four months and three different altitude levels have been analyzed: January and July (solstice months), April and October (equinoctial months), and 10, 30 and 50. hPa. The results are different for the months and altitudes considered. The highest correlations values appear in tropical zone at 30. hPa. The Brewer-Dobson circulation plays a key role in regulating the abundance of ozone, influenced by the quasi-biennial oscillation (QBO) circulation. Since the Brewer-Dobson is a slow circulation, correlations considering lags between one and 12 months were estimated. In this case, the highest correlations values are moving to subtropical latitudes at winter hemisphere, with different behaviors for three altitude levels considered.

Entomofauna asociada a garbanzo en el noroeste de Córdoba (Argentina); Entomofauna associated to chickpea in northwest of Cordoba (Argentina) Avalos, S.; Mazzuferi, V.; Fichetti, P.; Berta, Dominga Carolina; Carreras, J El garbanzo es un cultivo que se desarrolla en invierno. Entre los factores bióticos que limitan su producción se señalan a los insectos. El objetivo de este trabajo fue determinar las especies y abundancia de insectos fitófagos y sus enemigos naturales, asociados a dos cultivares de garbanzo (Chañaritos S156 y Norteño) en el noroeste de Córdoba. Durante 2006-2007, desde julio a noviembre se recolectaron manualmente los insectos presentes en sus diferentes estados de desarrollo en 30 plantas de cada cultivar tomadas al azar, y hojas con síntomas de moscas minadoras. A partir de la cría de insectos fitófagos se obtuvieron parasitoides. Se determinaron 15 especies de fitófagos y nueve de enemigos naturales. Las comunidades de insectos en ambas cultivares se hallaron dominadas por Lepidoptera, siendo Heliothis virescens la especie más abundante. Se registraron cinco especies de áfidos (Hemiptera) destacándose por su abundancia Acyrtosiphon pisum, cuatro especies de Thysanoptera que constituyen la primera cita sobre garbanzo y Liriomyza sp. (Diptera: Agromyzidae) en hojas minadas. Entre los predadores se encontraron Coccinellidae (Coleoptera) y Reduviidae (Hemiptera). Los parasitoides Hymenoptera Ichneumonidae y Chalcididae emergieron de H. virescens; Braconidae de áfidos; Eulophidae de Liriomyza sp. y Scelionidae de huevos de chinches. Por la etapa del cultivo en que se encuentra, daño directo y abundancia H. virescens sería la especie más perjudicial en la zona de estudio. Deben profundizarse las investigaciones referentes al rol como plagas potenciales de las principales especies de fitófagos y la incidencia de sus controladores naturales.; The chickpea is a crop that grows in winter. Among the biotic factors that limit the production are the insects. The aim of this work was to determine the species and abundance of insect herbivores and its associated natural enemies to cultivars of chickpea (Chañaritos S156 and Norteño) in the northwest of Cordoba. During 2006-2007, from July to November, insects in different states of development were collected manually in thirty plants of each cultivar that were chosen, as well as leave with symptoms of leafminers. From the breading of insect herbivores, specimens of parasitoids were obtained. Fifteen species of herbivores and nine of natural enemies associated to them were determined. The communities of insects in both cultivars were dominated by Lepidoptera, being Heliothis virescens the most abundant species. Five species of aphids (Hemiptera) were collected and Acyrtosiphon pisum was the most abundant, four registered species of Thysanoptera constitute the first appointment on the chickpea and Liriomyza sp. (Diptera: Agromyzidae) in leaves mined. The predators were Coccinellidae (Coleoptera) and Reduviidae (Hemiptera). Parasitoids Hymenoptera: Ichneumonidae and Chalcididae emerged from H. virescens; Braconidae of aphids; Eulophidae of Liriomyza sp. and Scelionidae of eggs of bugs. Because the stage of the crop in which they are, direct damage and abundance H. virescens could be the most detrimental species in the zone of study. The research of the role of the potential pests of the main phytophagous insect species and the incidence of their natural enemies should be developed.

Manuscritos desde el dolor: ser mujer y marginal en una comunidad judía Cohen, Elisa Beatriz En Argentina los grupos migratorios judíos llegados desde finales del siglo XIX intentaron fuertemente integrarse al medio, destacando especialmente sus aportes positivos. La trata de blancas organizada por la organización judía Tzwí Migdal salpicaba la credibilidad comunitaria, de allí la necesidad de su erradicación. Este artículo estudia el discurso de una de esas mujeres, preservado porque al haber sido asesinada, el hecho derivó en la organización de un expediente penal. Aparecen allí dos cartas encontradas en la misma escena del crimen en las que es posible observar que su condición de mujer inmoral no obstaculiza el despliegue de un interior profundamente humano. De esta manera, estudiamos el discurso y el lenguaje y aplicamos herramientas que nos permiten avizorar el mundo interior de la marginación, la soledad y el desamparo.

Hydraulic parameters and longitudinal distribution of macroinvertebrates in a subtropical andean basin; Parámetros hidráulicos y distribución longitudinal de macroinvertebrados en una cuenca andina subtropical; Parâmetros hidráulicos e de macroinvertebrados distribuição longitudinal em uma bacia andina subtropical Mesa, Leticia Mariana Se estudió la influencia de variables hidráulicas, de sustrato y variables físico-químicas sobre la distribución espacial de ensambles de macroinvertebrados en once rápidos de una cuenca subtropical andina del noroeste de Argentina. Variables hidráulicas complejas (velocidad de fricción, rugosidad de la velocidad fricción, número de Reynolds, número limitante de Reynolds, fuerza de fricción), rugosidad de sustrato, y variables físico-químicas (temperatura del agua, conductividad y pH) fueron utilizadas en virtud de identificar aquellas significativamente relacionadas con la distribución de la comunidad de macroinvertebrados. La temperatura del agua, la conductividad y el pH presentaron valores más altos en los sitios de menor altitud, mientras que la rugosidad del sustrato, la velocidad y fuerza de fricción fueron mayores en los sitios de más altos. La abundancia total de macroinvertebrados fue mayor en los sitios de menor altitud, mientras que la diversidad de invertebrados disminuyó desde sitios superiores hacia los inferiores. Los cambios longitudinales en la hidráulica, rugosidad del sustrato y conductividad representan los factores de mayor incidencia en la distribución de los invertebrados bentónicos de la cuenca del Río Lules.; A influência de variáveis hidráulicas, substrato e variáveis físico-químicas sobre a distribuição espacial das assembléias de macroinvertebrados foi investigada em onze rápido do um bacia hidrográfica subtropical Andina do noroeste da Argentina. Variáveis hidráulicas complexas (velocidade de fricção, rugosidade da velocidade de fricção, número de Reynolds, número de Reynolds limitando e força de fricção), rugosidade do substrato, rugosidade relativa e variáveis físico-químicas (temperatura, condutividade e pH) foram utilizados com o objetivo de identificar aqueles significativamente relacionadas com a distribuição da comunidade de macroinvertebrados. A temperatura da água, condutividade e pH apresentaram os maiores valores em sitios de baixa altitude, enquanto a rugosidade do substrato, a velocidade de fricção e força fricção foram maiores nos locais de maior altitude. A abundância total de macroinvertebrados foi maior em locais mais baixa altitude, enquanto a diversidade de invertebrados diminuiu de superior para os locais mais baixos. Alterações longitudinais na hidráulica, rugosidade do substrato e condutividade são importantes fatores ao longo do qual a comunidade bentônica Río Lules bacia é distribuído.; The influence of hydraulic, substratum and physicochemical variables on the spatial distribution of macroinvertebrate assemblages was analyzed in eleven riffles in a subtropical Andean basin of Northwestern Argentina. Complex hydraulic variables (shear velocity, roughness shear velocity, inferred boundary Reynolds number, Reynolds number, Froude number, shear stress), substrate roughness, relative roughness, and physicochemical variables (water temperature, conductivity and pH) were used in order to identify those significantly related with the distribution of macroinvertebrate assemblages. Water temperature, conductivity and pH were significantly higher in lower altitude sites, whereas substrate roughness, shear velocity and shear stress increased in upper sites. Total macroinvertebrate abundance was higher in lower reaches, whereas invertebrate diversity decreased from upper to lower sites. Longitudinal changes in hydraulic variables, substrate roughness and conductivity represent the major factors affecting the benthic invertebrates distribution of Lules River basin.

Next-generation biofuels: Survey of emerging technologies and sustainability issues Zinoviev, Sergey; Müller-Langer, Franziska; Das, Piyali; Bertero, Nicolas Maximiliano; Fornasiero, Paolo; Kaltschmitt, Martin; Centi, Gabriele; Miertus, Stanislav Next-generation biofuels, such as cellulosic bioethanol, biomethane from waste, synthetic biofuels obtained via gasification of biomass, biohydrogen, and others, are currently at the center of the attention of technologists and policy makers in search of the more sustainable biofuel of tomorrow. To set realistic targets for future biofuel options, it is important to assess their sustainability according to technical, economical, and environmental measures. With this aim, the review presents a comprehensive overview of the chemistry basis and of the technology related aspects of next generation biofuel production, as well as it addresses related economic issues and environmental implications. Opportunities and limits are discussed in terms of technical applicability of existing and emerging technology options to bio-waste feedstock, and further development forecasts are made based on the existing social-economic and market situation, feedstock potentials, and other global aspects. As the latter ones are concerned, the emphasis is placed on the opportunities and challenges of developing countries in adoption of this new industry.An overview of technical aspects of production technologies for next-generation biofuel is presented. Complemented with their related economical and environmental assessment results, an insight into the sustainability of the technologies, and an analysis of the opportunities and limits of future development, is given. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening of optimal pretreatment and reaction conditions for the isomerization-cracking of long paraffins over Pt/WO3-ZrO2 catalysts Busto, Mariana; Grau, Javier Mario; Vera, Carlos Roman Pretreatment and reaction conditions for the isomerization-cracking of long paraffins over commercial Pt/WO3-ZrO2 catalysts were screened. Optimal conditions were seeked for the production of short, high octane branched paraffins for the gasoline pool. n-C16 was used as a model molecule. The reaction over the acidic catalyst was used to adjust the size of the molecules to the boiling range of gasolines and to add branching in order to increase the octane number of the product. These adjustments had to be done while minimizing the production of light gases and getting a stable activity level. With respect to the pretreatment it was confirmed that the best calcination temperature of the tungstate oxoanion promoted hydroxides was 800 °C. Optimality was mostly related to the activity level. The optimum temperature coincides with the appearance of small WO3 crystallites which are thought to be center for creation of Brönsted acid sites in the presence of platinum and hydrogen. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at moderate temperature given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained with Pt/WO3-ZrO2 at WHSV = 18 h-1. The catalyst coking rate was a function of the H2/hydrocarbon ratio. A value of 6 was enough to attain a stable conversion value on Pt/WO 3-ZrO2. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity. Too high pressures enhanced hydrocracking and decreased the liquid yield. The results indicate that in general terms Pt/WO3-ZrO2 at moderate reaction conditions transforms a paraffinic heavy cut into a branched isomerizate that can be added to the gasoline pool to improve the quality properties. It was however found that under some conditions the octane gain is inversely proportional to the yield of light gases indicating that a high RON isomerizate can only be got at the expense of the liquid yield.

Screening of optimal pretreatment and reaction conditions for the isomerization-cracking of long paraffins over Pt/WO3–ZrO2 catalysts Busto, Mariana; Grau, Javier Mario; Vera, Carlos Roman Pretreatment and reaction conditions for the isomerization-cracking of long paraffins over commercial Pt/WO3-ZrO2 catalysts were screened. Optimal conditions were seeked for the production of short, high octane branched paraffins for the gasoline pool. n-C16 was used as a model molecule. The reaction over the acidic catalyst was used to adjust the size of the molecules to the boiling range of gasolines and to add branching in order to increase the octane number of the product. These adjustments had to be done while minimizing the production of light gases and getting a stable activity level. With respect to the pretreatment it was confirmed that the best calcination temperature of the tungstate oxoanion promoted hydroxides was 800 °C. Optimality was mostly related to the activity level. The optimum temperature coincides with the appearance of small WO3 crystallites which are thought to be center for creation of Brönsted acid sites in the presence of platinum and hydrogen. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at moderate temperature given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained with Pt/WO3-ZrO2 at WHSV = 18 h-1. The catalyst coking rate was a function of the H2/hydrocarbon ratio. A value of 6 was enough to attain a stable conversion value on Pt/WO 3-ZrO2. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity. Too high pressures enhanced hydrocracking and decreased the liquid yield. The results indicate that in general terms Pt/WO3-ZrO2 at moderate reaction conditions transforms a paraffinic heavy cut into a branched isomerizate that can be added to the gasoline pool to improve the quality properties. It was however found that under some conditions the octane gain is inversely proportional to the yield of light gases indicating that a high RON isomerizate can only be got at the expense of the liquid yield.

Biphasic effect of a primary tumor on the growth of secondary tumor implants Bruzzo Iraola, Juan; Chiarella, Paula; Meissl, Roberto Jose; Ruggiero, Raul Alejandro Background: The phenomenon of hormesis is characterized by a biphasic dose-response, exhibiting opposite effects in the low- and high-dose zones. In this study, we explored the possibility that the hormesis concept may describe the interactions between two tumors implanted in a single mouse, such that the resulting tumors are of different sizes. Materials and methods: We used two murine tumors of spontaneous origin and undetectable immunogenicity growing in BALB/c mice. A measure of cell proliferation was obtained by immunostaining for Ki-67 protein and by using the [3H] thymidine uptake assay. For serum fractionation, we utilized dialysis and chromatography on Sephadex G-15. Results: The larger primary tumor induced inhibitory or stimulatory effects on the growth of the smaller secondary one, depending on the ratio between the mass of the larger tumor relative to that of the smaller one, with high ratios rendering inhibition and low ratios inducing stimulation of the secondary tumor. Conclusion: Since metastases can be considered as natural secondary tumor implants in a tumor-bearing host and that they constitute the main problem in cancer pathology, the use of the concept of hormesis to describe those biphasic effects might have significant clinical implications. In effect, if the tumor-bearing host were placed in the inhibitory window, tumor extirpation could enhance the growth of distant metastases and, reciprocally, if placed in the stimulatory window, tumor extirpation would result not only in a reduction or elimination of primary tumor load but also in a slower growth or inhibition of metastases. © 2010 Springer-Verlag.

Costs and Benefits of Radio-collaring on the Behavior, Demography, and Conservation of Owl Monkeys (Aotus azarai) in Formosa, Argentina Juárez, Cecilia Paola; Rotundo, Marcelo Alejandro; Berg, Wendy; Fernandez Duque, Eduardo The benefits to researchers of capturing and collaring free-ranging primates are numerous, but so are the actual and potential costs to the individuals. We aimed to 1)evaluate quantitatively the possible demographic long-term costs of radio-collaring a free-ranging primate species, and 2) evaluate qualitatively the costs to the subjects and the overall benefits to the research program that results from monitoring a large number of groups with collared individuals during many years. Between 2000 and 2009, we captured, recaptured, and radio-collared 146 owl monkeys (Aotus azarai) to study the behavior, demography, and genetics of the species. To evaluate the potential long-term costs of the collaring procedures on the population, we compared the demographic composition of groups (n=20) in our core study area with those of undisturbed groups(n=20) in a control area within the same forest. Groups in both areas ranged in size between 2 and 5 individuals. Surprisingly, group size tended to be larger among the study groups owing to more infants and juveniles in those groups than in the control groups. The benefits to the research program have included, among others, the reliable identification of individuals, increased sample sizes, the recovery of specimens, studies of dispersal, outreach activities, and conservation education. Still, some of the benefits will become tangible only when the project persists on time; is fully approved and supported by local authorities; and has broad community participation, as well as conservation and education goals. Thus, any serious initiative to capture and collar individuals should be the result of an extremely careful evaluation of benefits and costs.

Ensayo y error: la reconversión de las estrategias empresariales en la disputa política en el espacio de trabajo : Metrovías y el Cuerpo de delegados de Subterráneos de Buenos Aires Ventrici, Patricia Para comprender la dinámica del desarrollo de la organización gremial es imprescindible dar cuenta de la relación siempre dinámica entre la dominación y la resistencia en el espacio de trabajo. La organización de los trabajadores y la corporación empresarial componen un vínculo estructuralmente contradictorio, en el que las acciones de cada parte condicionan y moldean el accionar de la otra, y en el que el objetivo de fondo es conservar la iniciativa política para ganar terreno en la disputa por el control del espacio de trabajo. Desde esta perspectiva, nuestro trabajo se propone aproximarse a la comprensión de la dinámica y transformaciones de la dominación social en un proceso micro, analizando las reconversiones de las estrategias empresariales en función de los acontecimientos políticos generados desde la práctica sindical al interior de la empresa Metrovías, concesionaria del transporte subterráneo en la Ciudad de Buenos Aires. Creemos que dicho caso reúne un conjunto de particularidades que dan cuenta de su potencialidad para reflexionar en torno a esta problemática, en la medida en que tiene lugar al interior de un tipo de empresa privatizada paradigmático de los cambios en las relaciones del trabajo en las últimas décadas, a la vez que se trata de un sector cuya organización sindical ha sido particularmente exitosa en las luchas por sus reivindicaciones. Frente al avance de estos procesos reivindicativos, a lo largo de los años, la empresa ha ido desarrollando distintas estrategias para contrarrestar la incidencia de la organización colectiva, que abarcaron desde políticas de coerción directa hasta técnicas orientadas a la fidelización e implicación afectiva de los trabajadores. Precisamente serán las causas, modos y consecuencias de estas transformaciones el objeto privilegiado de nuestra indagación.; To understand the dynamics of development of the trade organization is imperative to always realize the relationship dynamics between domination and resistance in the workspace. The organization of workers and business corporation comprise a structurally adversarial relationship in which each party shares condition and shape the actions of the other and in which the basic aim is to retain the political initiative to gain ground in the dispute over control of the workspace. From this perspective, our paper proposes closer to understanding the dynamics and transformations of social domination in a micro process, analyzing the restructuring of corporation strategies based on political events stemming from labor practice within the company Metrovías, licensee of the subway system in Buenos Aires. We believe that this case meets a set of characteristics that account for its potential to reflect on this issue, as it takes place within a kind of privatized company paradigmatic changes in labor relations in the past decades, while this is a sector whose union has been particularly successful in fighting for their claims. Encroachment of these reintegration process, over the years, the company has developed various strategies to counteract the impact of collective organization, ranging from direct coercion policies oriented techniques to the loyalty and emotional involvement of workers. It will be the causes, modes and consequences of these changes the privileged object of our inquiry.

The expression of Sphingosine kinase-1 in head and neck carcinoma Facchinetti, Maria Marta; Gandini, Norberto Ariel; Fermento, María Eugenia; Sterin, Norma Beatriz; Ji, Youngmi; Patel, Vyomesh; Gutkind, J. Silvio; Rivadulla, Maria G.; Curino, Alejandro Carlos Sphingosine kinase-1 (SPHK1) modulates the proliferation, apoptosis and differentiation of keratinocytes through the regulation of ceramide and sphingosine-1-phosphate levels. However, studies on the expression of SPHK1 in human head and neck squamous cell carcinoma (HNSCC) specimens are lacking. Therefore, the aim of the present work was to evaluate SPHK1 expression in human primary HNSCCs and to correlate the results with clinical and anatomopathological parameters. We investigated the expression of this protein by immunohistochemistry performed in tissue microarrays of HNSCC and in an independent cohort of 37 paraffin-embedded specimens. SPHK1 expression was further validated by real-time PCR performed on laser capture-microdissected tissue samples. The positive rate of SPHK1 protein in the cancerous tissues was significantly higher (74%) than that in the nontumor oral tissues (23%), and malignant tissues showed stronger immunoreactivity for SPHK1 than normal matching samples. These results were confirmed by real-time PCR quantification of SPHK1 mRNA. Interestingly, the positive expression of SPHK1 was associated with shorter patient survival time (Kaplan-Meier survival curves) and with the loss of p21 expression. Taken together, these results demonstrate that SPHK1 is upregulated in HNSCC and provide clues of the role SPHK1 might play in tumor progression.

Animal models in diabetes and pregnancy Jawerbaum, Alicia Sandra; White, Verónica The worldwide increase in the incidence of diabetes, the increase in type 2 diabetes in women at reproductive ages, and the cross-generation of the intrauterine programming of type 2 diabetes are the bases for the growing interest in the use of experimental diabetic models in order to gain insight into the mechanisms of induction of developmental alterations in maternal diabetes. In this scenario, experimental models that present the most common features of diabetes in pregnancy are highly required. Several important aspects of human diabetic pregnancies such as the increased rates of spontaneous abortions, malformations, fetoplacental impairments, and offspring diseases in later life can be approached by using the appropriate animal models. The purpose of this review is to give a practical and critical guide into the most frequently used experimental models in diabetes and pregnancy, discuss their advantages and limitations, and describe the aspects of diabetes and pregnancy for which these models are thought to be adequate. This review provides a comprehensive view and an extensive analysis of the different models and phenotypes addressed in diabetic animals throughout pregnancy. The review includes an analysis of the surgical, chemical-induced, and genetic experimental models of diabetes and an evaluation of their use to analyze early pregnancy defects, induction of congenital malformations, placental and fetal alterations, and the intrauterine programming of metabolic diseases in the offspring’s later life.

Climate-driven changes in air quality over Europe by the end of the 21st century, with special reference to Portugal Carvalho, A.; Monteiro, A.; Solman, Silvina Alicia; Miranda, A. I.; Borrego, C. Climate change alone may deeply impact air quality levels in the atmosphere because the changes in the meteorological conditions will induce changes on the transport, dispersion and transformation of air pollutants. The aim of this work was to evaluate the impact of climate change on the air quality over Europe and Portugal, using a reference year (year 1990) and a IPCC SRES A2 year (year 2100). The Hadley Centre global atmospheric circulation model (HadAM3P) was used to provide results for these two climatic scenarios, which were then used as synoptic forcing for the MM5-CHIMERE air quality modelling system. In order to assess the contribution of future climate change on O3 and PM concentrations, no changes in regional emissions were assumed and only climate change forcing was considered. The modelling results suggest that the O3 monthly mean levels in the atmosphere may increase almost 50 mg m3 across Europe in July under the IPCC SRES A2 scenario. In Portugal, this increase may reach 20 mg m3 . The changes of PM10 monthly average values over Europe will depend on the region. The increase in PM10 concentrations during specific months could be explained by the average reduction of the boundary layer height and wind speed.

Assessment of the impact of 2,4-dichlorophenoxyacetic acid (2,4-D) on indigenous herbicide-degrading bacteria and microbial community function in an agricultural soil Zabaloy, Maria Celina; Garland, Jay L.; Gómez, Marisa Anahi The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) may influence soil microbial communities by altering the balance between resident populations. Our objective was to assess the effect of environmentally relevant levels (ERLs) of 2,4-D on microbial community function and on the population dynamics of 2,4-D degrading bacteria using a microcosm approach. The most probable number approach was used to enumerate 2,4-D-degrading soil bacteria. Carbon substrates utilization was tested with a microtiter-based oxygen sensor system to evaluate short-term functional shifts caused by herbicide treatment. Shifts in the community in response to potential toxicity of 2,4-D were assessed in the agricultural soil and a reference forest soil using the pollution-induced community-tolerance (PICT) approach. Results indicated that the agricultural soil had a stable 2,4-D degrading population able to use the herbicide as C and energy source, which increases immediately after an ERL dose of 2,4-D and remains high for about 1 month after exposure has ceased. An enhanced, dose-dependent response to 2,4-D as substrate was observed in the microtiter assay, while heterotrophic bacterial activity appeared mostly unchanged. The PICT assay showed higher tolerance to 2,4-D in the agricultural soil than in the unexposed forest soil. Our results suggest that agricultural use of 2,4-D at recommended level leads to selection for (1) a copiotrophic degrader population and (2) a persistently herbicide-tolerant, but functionally similar, microbial community.

Effect of steviosides and system composition on stability and antimicrobial action of sorbates in acidified model aqueous systems Hracek, V. M.; Gliemmo, María Fernanda; Campos, Carmen Adriana The effect of steviosides on sorbate stability and on its antimicrobial action was studied in aqueous systems (pH 3.0). The use of steviosides decreased sorbate destruction in all the systems. Its effect on nonenzymatic browning (NEB) depended on the system composition. From the point of view of microbial stability, the steviosides promoted a slight increase in the minimum inhibitory concentration (MIC) of sorbates against Zygosaccharomyces bailii and Zygosaccharomyces rouxii. However, the main effect of steviosides was the protected action on sorbate destruction. This action was essential to ensure that the preservative residual level was higher than the MIC of the preservative to prevent the growth Z. bailii or Z. rouxii during storage. The results reported highlight that the use of steviosides in aqueous model systems resembling low-calorie sweet products can be useful to protect potassium sorbate (KS) from destruction and depending on the system composition also to decrease browning development.