Double Hopf bifurcation analysis using frequency domain methods Itovich, Griselda Rut; Moiola, Jorge Luis The dynamic behavior close to a non-resonant double Hopf bifurcation is analyzed via a frequency-domain technique. Approximate expressions of the periodic solutions are computed using the higher order harmonic balance method while their accuracy and stability have been evaluated through the calculation of the multipliers of the monodromy matrix. Furthermore, the detection of secondary Hopf or torus bifurcations (Neimark–Sacker bifurcation for maps) close to the analyzed singularity has been obtained for a coupled electrical oscillatory circuit. Then, quasi-periodic solutions are likely to exist in certain regions of the parameter space. Extending this analysis to the unfolding of the 1:1 resonant double Hopf bifurcation, cyclic fold and torus bifurcations have also been detected in a controlled oscillatory coupled electrical circuit. The comparison of the results obtained with the suggested technique, and with continuation software packages, has been included.

Antioxidants and methimazole in the treatment of Graves' disease: Effect on urinary malondialdehyde levels Guerra, Liliana Noemi; Rios, Maria del Carmen; Miler, Eliana Andrea; Moiguer, Silvia; Karner, Mirta; Burdman, Jose Adolfo We have postulated that metabolic oxidation could be the source of signs and symptoms of hyperthyroidism. The present study was designed to evaluate urinary malondialdehyde levels in Graves' disease and compare this oxidative stress biomarker with the clinical evolution of patients suffering this illness. We evaluated the concentration of urinary and serum malondialdehyde (MDA) in 36 patients with Graves' disease. Patients were treated with the antithyroid drug methimazole (MMI; Group A) or antioxidant mixture (200 mg vitamin E, 3 mg β-carotene, 250 mg vitamin C, 1 mg Cu, 7.5 mg Zn, 1.5 mg Mn, and 15 μg Se; Group B). MDA concentrations were higher in hyperthyroid patients compared to euthyroid controls, and a positive correlation was observed between serum and urinary MDA levels. Group A decreased urinary MDA to control values. There was a positive correlation between the clinical score and the heart rate of patients with urinary MDA before and during the treatment with MMI (Group A). Similar results were observed after treatment with the antioxidant mixture. Urinary MDA might be a good parameter in the follow-up of patients during MMI treatment. We proposed that oxidative stress correlates with signs and symptoms of hyperthyroidism.

Insecticide resistance in Argentine populations of tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae); Resistência a Inseticidas em Populações Argentinas de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) Lietti, Marcela; Botto, Eduardo Norberto; Alzogaray, Raúl Adolfo The tomato leafminer, Tuta absoluta (Meyrick), is one of the key pests of tomato in Argentina. Since its dispersal in the 1970s, chemical control has been the main method of controlling it. However, reduced efficacy of some of the recommended insecticides has been observed since the 1980s. The aim of this work was to study the toxicity of three insecticides widely used in chemical control of T. absoluta (abamectin, deltamethrin and methamidophos) on larvae from a laboratory susceptible population (CASTELAR) and two greenhouse populations (ROSARIO and BELLA VISTA). Insecticides were dissolved in acetone and topically applied to the mid-dorsal abdominal region of two-day old 4th instar larvae. LD50 values were estimated and the Resistance Ratio (RR) for each insecticide was calculated (RR = LD50 value of each greenhouse population/LD50 value of the susceptible population). ROSARIO and BELLA VISTA populations showed the following RRs values: > 68.38 for deltamethrin; 2.48 and 3.49 for abamectin, respectively; and 0.79 and 0.86 for metamidophos, respectively. Deltamethrin resistance observed in ROSARIO could be due to the high selective pressure exerted by pyrethroids in this location. Deltamethrin resistance in BELLA VISTA is more difficult to explain, because pyrethroids were scarcely used in the greenhouse where the insects were sampled. The incipient abamectin resistance detected in the BELLA VISTA population could result from the frequent use of this insecticide in this location, although natural variation can not be discarded.; A traça-do-tomateiro, Tuta absoluta (Meyrick), é uma das pragas chaves no tomateiro na Argentina. O controle químico tem sido o principal método de controle empregado a partir da sua dispersão nos anos 70. Contudo, tem-se observado uma redução na eficácia de alguns dos inseticidas recomendados a partir da década de 80. O objetivo deste trabalho foi estudar a toxicidade de três inseticidas amplamente usados no controle químico de T. absoluta (abamectina, deltametrina e metamidofós) em larvas de uma população susceptível de laboratório (CASTELAR) e duas populações colectadas em casa de vegetação (ROSARIO e BELLA VISTA). Inseticidas foram diluídos em acetona e aplicados topicamente na região dorsal mediana do abdome de larvas no segundo dia do quarto estágio larval. Para cada inseticida estimou-se o LD50 e calculou-se o Nível de Resistência (NR = LD50 de cada população de casa de vegetação/LD50 população de laboratório). As populações de ROSARIO e BELLA VISTA mostraram os seguintes NRs: > 68.38 para deltametrina; 2.48 e 3.49 para abamectina, respetivamente; e 0.79 e 0.86 para metamidofós, respetivamente. A resistência a deltametrina observada em ROSARIO pode ser resultante da alta pressão seletiva exercida pelos piretróides nessa localidade. A resistência incipiente a abamectina detectada em BELLA VISTA pode ter sido causado pelo uso freqüente do inseticida nessa localidade ou pode estar associada à variação natural.

Endothelin-1 stimulates the Na+/Ca2+ exchanger reverse mode through intracellular Na+ (Na+i)-dependent and Na+i-independent pathways Aiello, Ernesto Alejandro; Villa-Abrille, María Celeste; Dulce, Raul; Cingolani, Horacio Eugenio; Perez, Nestor Gustavo This study aimed to explore the signaling pathways involved in the positive inotropic effect (PIE) of low doses of endothelin-1 (ET-1). Cat papillary muscles were used for force and intracellular Na(+) concentration (Na(+)(i)) measurements, and isolated cat ventricular myocytes for patch-clamp experiments. ET-1 (5 nmol/L) induced a PIE and an associated increase in Na(+)(i) that were abolished by Na(+)/H(+) exchanger (NHE) inhibition with HOE642. Reverse-mode Na(+)/Ca(2+) exchanger (NCX) blockade with KB-R7943 reversed the ET-1-induced PIE. These results suggest that the ET-1-induced PIE is totally attributable to the NHE-mediated Na(+)(i) increase. However, an additional direct stimulating effect of ET-1 on NCX after the necessary increase in Na(+)(i) could occur. Thus, the ET-1-induced increase in Na(+)(i) and contractility was compared with that induced by partial inhibition of the Na(+)/K(+) ATPase by lowering extracellular K(+) (K(+)(o)). For a given Na(+)(i), ET-1 induced a greater PIE than low K(+)(o). In the presence of HOE642 and after increasing contractility and Na(+)(i) by low K(+)(o), ET-1 induced an additional PIE that was reversed by KB-R7943 or the protein kinase C (PKC) inhibitor chelerythrine. ET-1 increased the NCX current and negatively shifted the NCX reversal potential (E(NCX)). HOE642 attenuated the increase in NCX outward current and abolished the E(NCX) shift. These results indicate that whereas the NHE-mediated ET-1-induced increase in Na(+)(i) seems to be mandatory to drive NCX in reverse and enhance contractility, Na(+)(i)-independent and PKC-dependent NCX stimulation appears to additionally contribute to the PIE. However, it is important to stress that the latter can only occur after the primary participation of the former.

Plant functional traits, herbivore selectivity and response to sheep grazing in Patagonian steppe grasslands Cingolani, Ana María; Posse Beaulieu, Gabriela; Collantes, Marta Beatriz 1. In some ecosystems there is a positive feedback between forage quality and grazing intensity. This involves three components of plant tolerance to grazing: functional traits, herbivore selectivity and response to grazing. We analysed the relationships between these components at species and community levels in Patagonian steppe grasslands. 2. We measured plant functional traits [height, specific leaf area (SLA) and foliar toughness] and estimated sheep selectivity and grazing response indices for 35 plant species. Sheep selectivity indices were obtained from microhistological and species availability data, and grazing response indices from species abundances in sites with contrasting grazing intensities. We performed correlations and multiple regressions among the three types of variables across the pool of 35 species. 3. To analyse data at the community level, we computed weighted averages of traits and sheep selectivity indices for 34 floristic samples taken from each side of 17 fence lines with contrasting grazing intensities. Correlations between mean trait values and sheep selectivity across the 34 samples, and paired comparisons of those variables between sides of the fences, were performed. 4. Taller plants had leaves with lower SLA and/or higher toughness. Short species of intermediate toughness were selected more often by sheep, while SLA was not related to sheep selectivity. Short species with high SLA increased with grazing, while toughness and sheep selectivity were unrelated to grazing response. 5. At the community level, short swards with high average SLA had high selectivity indices and were more abundant on the most intensively grazed sides of fence lines. Leaf toughness was unrelated to other traits or to sheep selectivity, and showed no significant response to grazing. 6. Synthesis and applications. Intensive grazing can increase the forage value of grasslands by the creation of lawns dominated by tolerant species. However, results from this study showed that some plant species that were avoided by grazers also increased, indicating a potential risk of a shift in composition of grazing lawns towards states of low forage value. This suggests that periodic resting of lawns could be a good management strategy to favour palatable species, thereby minimizing the risk of undesirable shifts in the overall species composition.

Processes of Evolutionary Self-Organization in High Inflation Experiences Tohmé, Fernando Abel; Dabús, Carlos Darío; London, Silvia We study some features of the processes that have generated high inflation in Latin- American countries. The statistical evidence shows that these inflationary experiences are fractional brownian noises. Several authors showed that self-organized criticality (SOC) processes may constitute the best explanation of the origin of such noises. But this hypothesis requires that the underlying structure remains timeinvariant. We conjecture, instead, that the economic structures evolve in time being, at each stage of their evolution, self-organized structures. We find that such ESO (evolutionary self-organized) processes still generate fractional brownian noises. Thus, they seem to provide a better explanation for the economic phenomenon of high inflation.

Un código para la nación: familia, mujeres, derechos de propiedad y herencia en Argentina durante el siglo XIX Zeberio, Blanca Liliana La construcción de un nuevo orden social y político en la Argentina del siglo XIX presuponía, entre otros aspectos, la creación de un aparato jurídico institucional que sentara las bases de una sociedad centrada en el individuo como sujeto y creara reglas que aseguraran la consolidación de los mercados y de la propiedad privada...

Comunicación, energía y construcción: los pilares alemanes en el desarrollo tecnológico de Buenos Aires Mendez, Patricia Susana Este texto explica la historia de aquellas empresas de origen alemán instaladas en la Argentina de fines del siglo XIX y que perduraron hasta la década del 40. El análisis se centra en función de la productividad que tuvieron y su relación con la construcción; fundamentalmente, apoyadas en tres importantes renglones en el desarrollo tecnológico del país: la energía eléctrica, las comunicaciones y las construcciones en hormigón armado. Nombres como los de CATE, GEOPÉ, Dykerdoff and Widman y la Siemens en sus tres facetas se detallan desde su nacimiento, producción y obras realizadas en la ciudad de Buenos Aires.

Intoxicación por plantas tóxicas Tapia, Maria Ofelia; Murphy, Michael J. Los perros y gatos están expuestos a una variedad de plantas de interior y ornamentales en parques y jardines.

Educación terapéutica de las personas con diabetes tipo 2 Gagliardino, Juan Jose; Assad, Daniel; Gagliardino, Gabriel G.; Lahera, Elba; Rizzutti, Liliana; Zufriategui, Zulma Desde el capítulo 1 hemos venido diciendo que la diabetes mellitus (DM) es una enfermedad crónica que requiere tratamiento permenente a partir del momento de su diagnóstico. Ya en 1922 lo destacaba el Profesor Joslin y recientemente lo confirmaron diversos estudios previamente mencionados como Malmo, DCCT, UKPDS, DaQin, DPP2: “la educación de las personas con o en riesgo de desarrollar diabetes, es un componente esencial de las estrategias de prevención y tratamiento.”

"Computer, please, tell me what I have to do...": An approach to agent-aided application composition Campo, Marcelo Ricardo; Diaz Pace, Jorge Andres; Trilnik, Federico U. The process of starting to use any reuse technology is usually one of the most frustrating factors for novice users. For this reason, tools able to reduce the learning curve are valuable to augment the potential of the technology to rapidly build new applications. In this work, we present Hint, an environment for assisting the instantiation of Java applications based on software agents technology. Hint is built around a software agent that has the knowledge about how to use a reusable asset and, using this knowledge, is able to propose a sequence of programming activities that should be carried out in order to implement a new application satisfying the functionality the user wants to implement. The most relevant contribution of this work is the use of planning techniques to guide the execution of instantiation activities for a given technology.

Niveles de calidad de vida urbana y el estado de necesidades básicas en servicios e infraestructura Discoli, Carlos Alberto; San Juan, Gustavo Alberto; Rosenfeld, Elias; Martini, Irene; Barbero, Dante Andrés; Ferreyro, Carlos; Ramírez Casas, Jimena; Dicroce, Luciano; Dominguez, Cristina El trabajo expone aspectos teórico-conceptuales y resultados de un modelo de calidad de vida urbana (CVU). El mismo considera las interacciones entre los servicios básicos, la infraestructura y los aspectos ambientales, la cobertura y/o área de influencia y la opinión/percepción de los usuarios. Se elaboraron mapas orientados a territorializar y definir el estado de necesidades básicas relacionadas a los servicios urbanos y de infraestructura. Asimismo, se muestran las tendencias en términos de calidad de vida en función de la integración de diferentes aspectos urbanos y de su consolidación. Por último, se realizan algunas consideraciones metodológicas y operativas en cuanto a ventajas y limitaciones que se experimentan en la aplicación del modelo.; This work exposes theoretical-conceptual aspects and results of the quality of urban life model (CVU). It considers the interaction between the basic services, the infrastructure and environmental aspects, the influenced area, and users’ opinion/perception. Maps were elaborated that tend to express geographically and to define the basic necessities state related to the urban and infrastructure services. Tendencies are also shown in terms of life quality in function of different urban aspects integration and of their consolidation. Some methodological and operative considerations are carried out taking into account the advantages and limitations that are experienced in the application of the model.

Una visión global de la respuesta inmune Geffner, Jorge Raúl El sistema inmune permite que, a pesar de vivir en un ambiente densamente poblado de agentes microbianos potencialmente patógenos, sólo en pocas ocasiones suframos procesos infecciosos evidentes desde el punto de vista clínico. Más aún, cuando esto sucede, la infección suele resolverse con rapidez gracias al desarrollo de una respuesta inmune que integra mecanismos propios de las inmunidades innata y adaptativa...

Inmunidad innata: neutrófilos, macrófagos y células natural killer Trevani, Analía Silvina; Geffner, Jorge Raúl; Faimboin, Leonardo Mientras que sólo los linfocitos T y B componen las células de la inmunidad adaptativa, las células de la inmunidad innata comprenden un amplio abanico de tipos celulares. En sentido genérico, puede afirmarse que todas las células del organismo participan en la inmunidad innata, ya que son capaces de mediar diferentes mecanismos antimicrobianos. En el capítulo anterior, definimos la capacidad de los queratinocitos y células epiteliales de los tractos para orquestar una serie de respuestas tendientes a evitar la colonización de las superficies expuestas y eliminar los focos infecciosos que pudieran establecerse.

On limit cycle approximations in the van der Pol oscillator Padín, Mirta S.; Robbio, Federico I.; Moiola, Jorge Luis; Chen, Guanrong This paper applies bifurcation analysis to the well-known van der Pol oscillator to obtain approximations of its periodic solutions in the nearly sinusoidal regime. A frequency domain method based on harmonic balance approximations is used for small values of the bifurcation parameter. Moreover, a comparison with some other frequency domain approaches is also given. Finally, a total harmonic distortion is computed using the information provided by the frequency domain approach.

Expression of Fluorescent Genes in Trypanosoma cruzi and Trypanosoma rangeli (Kinetoplastida: Trypanosomatidae): Its Application to Parasite-Vector Biology Guevara, Palmira; Dias, Manuel; Rojas, Agustina; Crisante, Gladys; Abreu Blanco, Maria Teresa; Umezawa, Eufrozina; Vazquez, Martin Pablo; Levin, Mariano Jorge; Añez, Nestor; Ramirez, Jose Luis Two Trypanosoma cruzi-derived cloning vectors, pTREX-n and pBs:CalB1/CUB01, were used to drive the expression of green fluorescent protein (GFP) and DsRed in Trypanosoma rangeli Tejera, 1920, and Trypanosoma cruzi Chagas, 1909, isolates, respectively. Regardless of the species, group, or strain, parasites harboring the transfected constructs as either episomes or stable chromosomal integrations showed high-level expression of fluorescent proteins. Tagged flagellates of both species were used to experimentally infect Rhodnius prolixus Stal, 1953. In infected bugs, single or mixed infections of T. cruzi and T. rangeli displayed the typical cycle of each species, with no apparent interspecies interactions. In addition, infection of kidney monkey cells (LLC-MK2) with GFP-T. cruzi showed that the parasite retained its fluorescent tag while carrying out its life cycle within cultured cells. The use of GFP-tagged parasites as a tool for biological studies in experimental hosts is discussed, as is the application of this method for copopulation studies of same-host parasites

Zeolite washcoating onto cordierite honeycomb reactors for environmental applications Zamaro, Juan Manuel; Ulla, Maria Alicia del H.; Miro, Eduardo Ernesto The preparation conditions to obtain zeolite washcoats with optimum loading and homogeneous distribution are studied for mordenite, ferrierite and ZSM5, The slurry concentration and the number of immersions were combined to obtain different coating thickness and geometry. The solid concentration increases the viscosity of the slurry resulting in an exponential growth of the zeolite loading. In order to obtain more homogeneous washcoatings it is preferable to use diluted suspensions and perform more than one immersion. It was found that the washcoating adherence increases with the decrease in the size of the aggregates deposited on the monolith. This improves the packaging and interaction between particles and facilitates a convenient filling of the surface cordierite macropores, producing a more effective anchorage. In this vein, the order of washcoat stability tested with an ultrasound method is ZSM5 > mordenite > ferrierite. The addition of SiO2 as a binder improves the adherence of the three zeolites under study probably due to an improvement in the interparticle cohesion. The performance of an In-ZSM5 washcoated monolith was tested for the selective reduction of NOx with methane under oxygen excess. It was observed that the activity of the monolithic catalyst was as good as those for the In-ZSM5 powder, which indicates that there are no diffusive restrictions due to coating thickness.

Morfometría de los estadios ninfales de Cornops aquaticum Bruner (1906) (Acrididae: Leptysminae) en Argentina; Morphometry of the nymphal stages in Cornops aquaticum (Acrididae: Leptysminae) from Argentina Franceschini, Maria Celeste; Capello, Soledad; Lhano, Marcos G.; Adis, Joachim; de Wysiecki, Maria Laura Cornops aquaticum está ampliamente distribuída en toda Latinoamérica y su ciclo biológico está estrechamente relacionado a Eichhornia crassipes (Mart.) Solms y Eichhornia azurea KUNTH (Pontederiacea). La correcta determinación de los estadíos ninfales de C. aquaticum resulta de fundamental importancia para conocer la estructura de las poblaciones en una determinada región. El objetivo del presente trabajo es evaluar la utilidad de los caracteres morfométricos de las ninfas de C. aquaticum para determinar los distintos estadíos ninfales. Para esto se realizó la cría de ninfas de primer estadío en laboratorio, en Corrientes (N= 29, 28 y 24) y Santa Fé (N= 26, 16), donde se encuentran diferentes condiciones de temperatura e insolación. Las ninfas fueron pesadas y medidas al inicio de la experiencia y después de producida la ecdisis: distancia desde el fastigium hasta el final de las pterotecas o pronotum (A), distancia desde el fastigium hasta el final del abdomen (B), longitus del fémur posterior (H), longitud de la antena (L), número de antenómeros (N° Ant. ) y peso fresco (Peso). La longitud del fémur posterior mostró ser la medida más constante en cada estadío ninfal. En contraste con otros caracteres, presenta la ventaja de ser preciso y constituye además una medida sencilla de registrar cuando se trabaja con un gran número de individuos. Con la información morfométrica, se espera complementar los estudios morfológicos ya existntes y contribuir al conocimiento ecológico de la especie.; Cornops aquaticum is a widely distributed species in Latin America and has a life cycle associated with Eichhornia crassipes (MART.) SOLMS and E. azurea (SW.) KUNTH (Pontederiaceae). The correct determination of the nymphal stages in C. aquaticum is important to study the population structure in a specific region. The purpose of this study is to evaluate if morphometric characters can be used to determine the different nymphal stages in C. aquaticum. For this reason, first-stage nymphs were reared at two localities (Corrientes: N = 29, 28, 24; Santa Fe: N = 26, 16) under different conditions of temperature and insolation. After hatching and after each moult, fresh weight ("Peso") of nymphs was determined and measurements of the following morphometrical characters were taken: distance from fastigium to end of pterothecas or pronotum (A), distance from fastigium to end of abdomen (B), length of hind femur (H), length of antenna (L), and number of antennal segments (N Ant.). Length of the hind femur (H) was the most constant and precise character in each nymphal stage, subjected to little measuring bias and easy to measure when working with a high population density. Morphometrical and morphological data are expected to contribute to the ecological knowledge of this species.

Galectins as modulators of tumour progression Liu, Fu Tong; Rabinovich, Gabriel Adrián Galectins are a family of animal lectins with diverse biological activities. They function both extracellularly, by interacting with cell-surface and extracellular matrix glycoproteins and glycolipids, and intracellularly, by interacting with cytoplasmic and nuclear proteins to modulate signalling pathways. Current research indicates that galectins have important roles in cancer; they contribute to neoplastic transformation, tumour cell survival, angiogenesis and tumour metastasis. They can modulate the immune and inflammatory responses and might have a key role helping tumours to escape immune surveillance. How do the different members of the Galectin family contribute to these diverse aspects of tumour biology?

The role of urban air pollutants on the heavy metals accumulation performance of Usnea amblyoclada Carreras, Hebe Alejandra; Wannaz, Eduardo Daniel; Pérez, Carlos A.; Pignata, Maria Luisa Lichens incorporate heavy metals according to a selectivity sequence; therefore, their uptake rate can be affected when elements with a high affinity for cell wall exchange sites or that provoke harmful alterations to the metabolism of lichen thalli are present in the environment.The aim of this study was to examine the effect of urban pollutants on the accumulation of some heavy metals in Usnea amblyoclada.Lichen samples were transplanted for 1 month to both a polluted and a nonpolluted area in Córdoba, Argentina.They were then collected and soaked in tridistilled water or in solutions containing different concentrations of Cu, Ni, Pb, and Zn salts.The uptake of Cu2+, Ni2+, Zn2+, and Pb2+, and other parameters indicative of lichen damage were measured in all the lichen samples.The thalli retrieved from the polluted area showed significant increases in both the malonaldehyde content and the electrical conductivity of the water in which they had been immersed.These results indicate that the atmospheric pollutants could be responsible for the significant damage to the lichen’s cellular membranes, thus altering several mechanisms related to the uptake of heavy metals.Both the area of transplantation and the concentration of the metallic solutions had significant effects on the levels of Cu, Ni, and Pb measured in lichen thalli; however, no significant differences were observed in Zn concentrations.The highest uptakes corresponded to Pb and Cu, suggesting that they probably have a higher affinity with the lichen cell wall exchange sites.This study confirms the fact that, although lichens can be useful biological indicators, the physiological mechanisms involved in metal uptake should be carefully analyzed.Therefore, when estimating the heavy metal content of an environment, the competitive mechanism for cation uptake should be considered especially in areas where the presence of high levels of metals with a strong binding affinity is suspected.The presence of secondary products in the lichens could be responsible for the selective uptake of cations and for a possible tolerance to their presence.