Stationary and dynamical descriptions of strong correlated systems Goldberg, Edith Catalina; Flores, F.; Monreal, R. This work is mainly devoted to the description of processes that involve the interaction between an atom and a surface, in which a strong Coulomb repulsion on the atomic site sUd limits the charge exchange to one electron sinfinite-U limitd. In this limit, the Anderson Hamiltonian for a many-fold sNd of states localized on the atomic site can be represented in terms of auxiliary bosons and physical operators in the mixed bosonelectron space can be defined. In this work the Hamiltonian is solved by defining appropriate Green’s functions for physical operators. Then we solved the equations of motion of these Green’s functions, up to a second order in the atom-surface coupling, either for the stationary case or for a real time-dependent problem. We show that our approach reproduces the known exact results in the nondegenerate sN=1d case, and for Ns1 gives excellent agreement with exact calculations and approximations valid for large N sthe 1/N expansiond. Finally, the accurate description of dynamical processes is shown by the comparison with the exact results available for a small four-level system. In this case we also compare with results obtained by using the noncrossing approximation and with the usual spinless model calculation.

Surfaces and local anisotropy effect in the magnetic order of Fe-Co-B nanoparticles Molina Concha, B.; Zysler, Roberto Daniel; Troiani, Horacio Esteban; Romero, H. 3 nm (FexCo1 x)yB1 y (0pxp1; y 0:6) nanoparticles were synthesized by chemical route. XDR and TEM measurement show the amorphous nature of the samples. Size distribution was characterized by light-scattering measurement. Magnetization vs. magnetic field measurements at room temperature show hysteresis loop for all compositions, typical of blocked single domains. In powder samples, room temperature coercive field and remanent are larger for Fe- or Co-rich composition, and saturation magnetization exhibit a minimum at x ¼ 0:15: This behaviour is related to the composition of the different local anisotropy associated to Fe and Co ions.

Estudio micropaleontológico de dos secuencias de la Cuenca Neuquina, centro oeste de Argentina; A micropalaeontological study of two Jurassic sequences in the Neuquén Basin, central-west Argentina Ballent, Sara Cristina An example of application of calcareous microfossils to palaeoenvironmental reconstruction is presented. Foraminifers and Ostracoda from across the Aalenian-Bajocian boundary at the Picún Leufú section and Mid Callovian at the María Rosa Curicó section, both in Neuquén Basin, in central western Argentina, are analysed. The resulting data are presented as the following parameters: faunal density and specific diversity in both groups; test composition and vertical distribution of morphogroups in foraminifers; carapace morphology, adult valves to carapaces ratio and population age-structures in Ostracoda. Conclusions from the microfossils agree with those proposed by other authors based on sedimentological and palynological data. Additionally, two new Jurassic species (Middle Callovian) are described as new: the attached foraminifer Ammovertellina simeonae sp. nov. and the ostracod Cytherella mediodepressa sp. nov. Resumen. ESTUDIO MICROPALEONTOLÓGICO DE DOS SECUENCIAS DE LA CUENCA NEUQUINA, CENTRO OESTE DE ARGENTINA. Se analizan las asociaciones de foraminíferos y ostrácodos en las secciones Picún Leufú (límite Aaleniano-Bajociano) y María Rosa Curicó (Caloviano medio), ambas en la cuenca Neuquina. Los datos fueron organizados de acuerdo a los siguientes parámetros: densidad faunística y diversidad específica en ambos grupos; composición de la conchilla y distribución vertical de morfogrupos en foraminíferos; morfología del caparazón, relación en adultos entre valvas y caparazones y estructura poblacional en ostrácodos. Las conclusiones obtenidas a partir de los microfósiles coinciden con aquéllas provenientes de estudios sedimentológicos y palinológicos. Se describen como nuevos para el Caloviano medio, el foraminífero adherido Ammovertellina simeonae sp. nov. y el ostrácodo Cytherella mediodepressa sp. nov.; An example of application of calcareous microfossils to palaeoenvironmental reconstruction is presented. Foraminifers and Ostracoda from across the Aalenian-Bajocian boundary at the Picún Leufú section and Mid Callovian at the María Rosa Curicó section, both in Neuquén Basin, in central western Argentina, are analysed. The resulting data are presented as the following parameters: faunal density and specific diversity in both groups; test composition and vertical distribution of morphogroups in foraminifers; carapace morphology, adult valves to carapaces ratio and population age-structures in Ostracoda. Conclusions from the microfossils agree with those proposed by other authors based on sedimentological and palynological data. Additionally, two new Jurassic species (Middle Callovian) are described as new: the attached foraminifer Ammovertellina simeonae sp. nov. and the ostracod Cytherella mediodepressa sp. nov.

Static response in disk packings Moukarzel, Cristian Fernando; Pacheco Martínez, Hector; Ruiz-Suarez, J. C.; Vidales, Ana Maria We present experimental and numerical results for displacement response functions in packings of rigid frictional disks under gravity. The central disk on the bottom layer is shifted upwards by a small amount, and the motions of disks above it define the displacement response. Disk motions are measured with the help of a still digital camera. The responses so measured provide information on the force-force response, that is, the excess force at the bottom produced by a small overload in the bulk. We find that, in experiments, the vertical-force response shows a Gaussian-like shape, broadening roughly as the square root of distance, as predicted by diffusive theories for stress propagation in granulates. However, the diffusion coefficient obtained from a fit of the response width is ten times larger than predicted by such theories. Moreover we notice that our data is compatible with a crossover to linear broadening at large scales. In numerical simulations on similar systems (but without friction), on the other hand, a double-peaked response is found, indicating wave-like propagation of stresses. We discuss the main reasons for the different behaviors of experimental and model systems, and compare our findings with previous works.

Remaining coverage in associative desorption process Furlong, Octavio Javier; Manzi, Sergio Javier; Costanza, Gregorio José; Pereyra, Victor Daniel In this paper the kinetic of dissociative adsorption of dimers followed by associative desorption is analyzed. The coupled differential equations which describe the kinetics of the process were obtained by applying the so-called local evolution rules. Particular interest presents the irreversible desorption process. In fact, given that desorption proceeds from the reacting nearest-neighbor monomers, a remaining coverage results from those isolated particles when the mobility is neglected, therefore, the resulting configuration can be considered as a jamming state of the system. The exact solution for the remaining coverage is obtained in one-dimensional chain, where the effect of the lateral interactions are also included. The two-dimensional case is analyzed by using Monte Carlo simulation. The equilibrium solutions and the thermal desorption spectra are also studied.

¿Fundamentar o resignificar?: Observaciones sobre el sentido moderno de tolerancia Parente, Diego Carlos El presente trabajo indaga la siguiente pregunta: ¿es la noción moderna de tolerancia un concepto obsoleto o, al menos, debilitado? Y, en caso afirmativo, ¿cómo sustituirlo, cómo resignificarlo, cómo tomar su lugar, teniendo en cuenta que dicho concepto no regula algo irrelevante sino la misma trama de las relaciones humanas? Para sugerir una respuesta, se intenta previamente una aproximación a otra serie de nociones que se conectan de manera directa con la tolerancia (tales como ciudadanía y democracia). Posteriormente, se revisan el rescate rortyano de la noción humeana de "empatía" a fin de defender una alternativa a la tolerancia moderna que sea capaz de evitar su carácter paternalista.

Larval development of the subantarctic king crabs Lithodes santolla and Paralomis granulosa reared in the laboratory Calcagno, Javier Ángel; Anger, K.; Lovrich, Gustavo Alejandro; Thatje, S.; Kaffenberger, A. The larval development and survival in the two subantarctic lithodid crabs Lithodes santolla (Jaquinot) and Paralomis granulosa (Molina) from the Argentine Beagle Channel were studied in laboratory cultures. In L. santolla, larval development lasted about 70 days, passing through three zoeal stages and the megalopa stage, with a duration of approximately 4, 7, 11 and 48 days, respectively. The larval development in P. granulosa is more abbreviated, comprising only two zoeal stages and the megalopa stage, with 6, 11 and 43 days' duration, respectively. In both species, we tested for effects of presence versus absence of food (Artemia nauplii) on larval development duration and survival rate. In P. granulosa, we also studied effects of different rearing conditions, such as individual versus mass cultures, as well as aerated versus unaerated cultures. No differences in larval development duration and survival were observed between animals subjected to those different rearing conditions. The lack of response to the presence or absence of potential food confirms, in both species, a complete lecithotrophic mode of larval development. Since lithodid crabs are of high economic importance in the artisanal fishery in the southernmost parts of South America, the knowledge of optimal rearing conditions for lithodid larvae is essential for future attempts at repopulating the collapsing natural stocks off Tierra del Fuego.

Argentinian unhatched pterosaur fossil Chiappe, Luis; Codorniú Dominguez, Laura Susana; Grellet-Tinner, Gerald; Rivarola, David Luciano Our knowledge of the eggs and embryos of pterosaurs, the Mesozoic flying reptiles, is sparse. Until now, the recent discovery of an ornithocheirid embryo from 121-million-year-old rocks in China1 constituted the only reliable evidence of an unhatched pterosaur. Here we describe an embryonic fossil of a different pterosaur from the Early Cretaceous lacustrine deposits of Loma del Pterodaustro (the Lagarcito Formation, which is about 100 million years old) in central Argentina. This new fossil provides insight into the eggshell morphology, early growth and nesting environments of pterosaurs.

Antropología, alternativa a las políticas ambientales Feito, Maria Carolina En este trabajo pretendemos reivindicar la importancia, pocas veces reconocida por los decisores políticos, de la investigación antropológica para el desarrollo e implementación de políticas ambientales locales, describiendo la metodología cualitativa aplicada en el trabajo de campo etnográfico y mostrando algunos ejemplos de aplicación del abordaje antropológico en distintas áreas de políticas, con especial atención a las ambientales. Aprendiendo de qué manera los residentes locales definen sus necesidades y escuchando sus sugerencias para resolver problemas, el etnógrafo puede proveer a los analistas políticos importante información para el diseño de políticas que involucren las necesidades de poblaciones específicas, más que de "tipos genéricos" difícilmente compatibles con la realidad. Esta perspectiva otorga un alto grado de valoración al impacto del conocimiento local en políticas exitosas. Las herramientas etnográficas tienen a su vez un valor incalculable para realizar recomendaciones políticas. Las políticas públicas pueden tomar información de las "vidas privadas". La comprensión de la diversidad de experiencias de vida, vista desde los ojos de los actores sociales participantes, precisa de manera esencial un enfoque etnográfico.

Antropología y políticas sociales rurales: una relación fructífera pero poco reconocida Feito, Maria Carolina Este trabajo reivindica la relevancia, pocas veces reconocida por quienes toman las decisiones políticas, de la investigación antropológica para el desarrollo de políticas sociales locales en ámbitos rurales, considerando el concepto de "desarrollo" como una construcción social, describiendo la metodología cualitativa del trabajo de campo etnográfico y mostrando ejemplos recientes de contribuciones del abordaje antropológico a las políticas sociales rurales. Aprendiendo cómo los residentes locales definen sus necesidades, escuchando sus sugerencias para resolver problemas, el etnógrafo puede proveer a los analistas políticos importante información para el diseño de políticas que involucren las necesidades de poblaciones específicas, más que de "tipos genéricos" difícilmentecompatibles con la realidad. Esta perspectiva valora tanto el impacto delconocimiento local en políticas exitosas, como la pertinencia de las herramientas etnográficas para realizar recomendaciones políticas. La comprensión de la diversidad de experiencias de vida, analizada desde la perspectiva de los actores sociales participantes en políticas rurales, precisa de manera esencial un enfoque etnográfico.

The Korn inequality for Jones domains Durán, Rodrigo Gonzalo; Muschietti, Maria Amelia In this paper we prove the Korn inequality, and its generalization to Lp, 1 < p < ∞, for bounded domains Ω ⊂ Rn, n ≥ 2, satisfying an ( , δ) condition.

Chromosome numbers in species of Grindelia (Asteraceae, Astereae) from the Meseta del Somuncura (Patagonia, Argentina) Bartoli, Adriana; Tortosa, Roberto Daniel Diploid chromosome number (2n=12) for Grindelia coronensis A. Bartoli & Tortosa and G. pygmaea Cabr. are reported for the first time. Somatic chromosome morphology for both species are described. The karyotype (2n=12) is composed by 6m+4st+2st-sat. The achene morphology of G. pygmaeae is comunicated for the first time.; Se citan por primera vez el número cromosómico diploide de Grindelia coronensis A. Bartoli & Tortosa (2n=12) y de G. pygmaeae Cabr. (2n=12). Se describe la morfología de los cromosomas somáticos para ambas especies, cuyo cariotipo está compuesto por 2n=12=6m+4st+2st-sat. Además, se comunica por primera vez la morfología de los aquenios de G. pygmaeae.

Estanislao Zeballos y los incentivos para la naturalización de extranjeros: Perfil de un legislador que buscó comunicar identidad Micheletti, María Gabriela Hombre público polifacético, el rosarino Estanislao Severo Zeballos (1854-1923) dedicó su vida a bregar por el progreso de su patria, siendo uno de los aspectos destacados de su actuación el vinculado a su preocupación por propender a la colonización del país a través de la inmigración. Este artículo pretende indagar, en el marco de la labor desplegada por Zeballos como diputado nacional, acerca del rol que buscó desempeñar como comunicador de identidad al extranjero inmigrante, ya que no sólo se interesó por el aporte material que podía redituar la presencia de éste, sino que demostró una temprana toma de conciencia acerca de la necesidad de incorporarlo efectivamente a la nacionalidad argentina. Para ello, se manifestó a favor de aplicar una política de incentivos a la naturalización de los extranjeros: la tierra, la jubilación y el voto electoral se convirtieron así, en el pensamiento del legislador, en adecuados alicientes que harían al inmigrante atractiva la idea de optar por la ciudadanía argentina. El objetivo final y fundamental perseguido, al que la naturalización coadyuvaría, era el de lograr la nacionalización cultural de las crecientes masas inmigratorias, a fin de evitar la temida disolución de la identidad nacional.

Patterns of ethnic, linguistic, and geographic heterogeneity of palmar interdigital ridge counts in the Indian subcontinent Reddy, B. Mohan; Demarchi, Dario; Bharati, S.; Kumar, Vikrant; Crawford, Michael H. Published data on palmar interdigital ridge counts (a-b, b-c, and c-d) among 57 populations from the Indian subcontinent were analyzed with reference to ethnic, socioeconomic, linguistic, and geographic affiliations of the studied populations. The spatial autocorrelation analysis suggests significant correlation between dermatoglyphic and geographic distances. The congruence with the ethnic semblance of the groups is also apparent in the data, and, in fact, the multiresponse permutation procedure did suggest highly significant within-group homogeneity, confirming the biological validity of the social and ethnic criteria used in the analysis. The plots of populations on the first two principal components, accounting for 92% of the total variance, complement and support the results based on the other analyses, which show certain ethnic and geographic patterns. These findings can serve as baseline information for future studies on population variation in India, particularly studies based on molecular genetic markers, a trend that has already gained momentum.

Genetic structure and gene flow in Gran Chaco populations of Argentina: Evidence from Y-chromosome markers Demarchi, Dario; Mitchell, R. John The Gran Chaco region of central South America has been settled by humans for only the last 4,000-5,000 years. To investigate population structure and variation in this region's indigenous population, we scored males from tribes of the Argentinean part of the Gran Chaco (Pilagá, Wichí, and Toba, representing two major language groups, the Mataco and Guaycurú) for a number of Y-chromosome polymorphisms. The markers included eight microsatellites (DYS19, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, and DYS439) and the unique native American single nucleotide polymorphism, DYS199. Sixty males (77%) from the total sample carried the DYS199T chromosome, and these were the focus of the present analysis. Unlike most other native Americans, Gran Chaco males show a moderate level of diversity at the DYS19 locus but still less than that seen in non-native Americans. The FST value for Y-chromosome markers in Gran Chaco was 0.107, a value that is more than double that found for mtDNA haplogroups in the same tribes but is not particularly high compared with other Y-chromosome studies. Phylogenetic trees based on all eight microsatellites showed relatively poor correlation of the tribes with either geography or language, and this is possibly explained by their ecology. They are seasonal hunters living in small bands, and under such circumstances drift will be a powerful evolutionary force. An UPGMA tree based on five microsatellites (DYS19, DYS390, DYS391, DYS392, and DYS393), however, showed a more positive relationship, suggesting that DYS437, DYS438, and DYS439 may behave differently from the other microsatellites. No association was found between maternal and paternal lineage distributions. The time to the most recent common ancestor of the DYS 199T chromosome is calculated to lie between 13,000 and 26,000 years. This range is consistent with estimates from other Y-chromosome studies as well as with estimates from mtDNA and the archeology of the colonization of South America. We conclude that the male lineages present in the contemporary Gran Chaco population reflect the level of diversity found in South America and that the region's male founders did not carry a restricted gene pool.

Mitochondrial extracellular signal-regulated kinases 1/2 (ERK1/2) are modulated during brain development Alonso, Mariana; Melani, Mariana; Converso, Daniela Paola; Jaitovich, Ariel; Paz, Cristina del Valle; Carreras, Maria Cecilia; Medina, Jorge Horacio; Poderoso, Juan José Intracellular activation and trafficking of extracellular signal-regulated protein kinases (ERK) play a significant role in cell cycle progression, contributing to developmental brain activities. Additionally, mitochondria participate in cell signalling through energy-linked functions, redox metabolism and activation of pro- or anti-apoptotic proteins. The purpose of the present study was to analyze the presence of ERK1/2 in mitochondria during rat brain development. Immunoblotting, immune electron microscopy and activity assays demonstrated that ERK1/2 are present in fully active brain mitochondria at the outer membrane/intermembrane space fraction. Besides, it was observed that ERK1/2 translocation to brain mitochondria follows a developmental pattern which is maximal between E19-P2 stages and afterwards declines at P3, just before maximal translocation to nucleus, and up to adulthood. Most of mitochondrial ERK1/2 were active; upstream phospho-MAPK/ERK kinases (MEK1/2) were also detected in the brain organelles. Mitochondrial phospho-ERK1/2 increased at 1 μM hydrogen peroxide (H2O2) concentration, but it decreased at higher 50-100 μm H2O 2, almost disappearing after the organelles were maximally stimulated to produce H2O2 with antimycin. Our results suggest that developmental mitochondrial activation of ERK1/2 cascade contributes to its nuclear translocation effects, providing information about mitochondrial energetic and redox status to the proliferating/differentiating nuclear pathways.

Historia y complejidad. La Historia del Tiempo Presente Figallo, Beatriz Josefina; García, Josefa El campo historiográfico de la Historia del Tiempo Presente, con su discurso peculiar nos propone una alternativa científica de alta capacidad explicativa para entender las claves de la relación pasado-presente-futuro. El planteo de este artículo busca contribuir en la conceptualización de la historia protagonizada por las generaciones vivas de la Argentina y América Latina, mediante categorías de análisis que consideran los fenómenos de crisis, de incertidumbre de tiempo corto – el acontecimiento-, con una apuesta fuerte por la interdisciplinariedad y por la atención a lo político, valorando la información proporcionada por los testimonios orales, la literatura, la música y el cine que dan cuenta de las sociedades que los produjeron y las nuevas fuentes electrónicas. El paradigma de la complejidad posibilita pensar la historia del tiempo presente concibiendo a la realidad como una dificultad perpetua para ser explicada, abriéndose a un gran número de posibilidades de interpretación.

Roya de la soja: Cómo prepararse para enfrentar a esta amenaza Ploper, Leonardo Daniel; Gálvez, M. Roberto; Devani, Mario Rodolfo; González, Victoria; Zamorano, María Antonia; Lenis, Julián M.; Ledesma, Fernando Martín La roya "asiática" de la soja, causada por Phakopsora pachyrhizi, ya se encuentra presente en numerosas regiones del país, incluido el noroeste argentino (NOA).  Esta situación plantea un nuevo desafío para la producción local de soja, ya que se trata de una enfermedad conocida por haber provocado severos daños en lotes ubicados en varios continentes.  En virtud de su alto poder de dispersión y su gran potencial de daño, se deberá estar muy atento al progreso de esta patología en las regiones en donde ya fue detectada, así como de su posible aparición en los sitios en donde aún no fue encontrada.  En el caso del NOA, la confirmación de la presencia de esta grave enfermedad obliga a productores y técnicos a incluir en sus esquemas de manejo del cultivo prácticas tendientes a disminuir riesgos de la ocurrencia de costosas epifitias.  En el presente trabajo se presenta información sobre la presencia de la roya de la soja en el NOA y se proponen medidas tentativas de manejo de la enfermedad, considerando especialmente que aún se desconoce el impacto real que la misma pueda llegar a tener en los cultivos de soja de la región.

«Atal allur a catade»: recuperación figural de la Antigüedad en la Cantigas de Santa María de Alfonso el Sabio Disalvo, Santiago Anibal Existe un nexo figural o tipológico entre el evento histórico relatado en la Cantiga de Santa María 205 y un pasaje de la Estoria de España, ambas obras alfonsíes que no suelen estudiarse en relación. Este recurso, que es sólo una muestra de la rica utilización de la tipología en el cancionero, evidencia un propósito de recuperación y superación simbólica («alegórica») del pasado pagano en el contexto más amplio de textos alfonsíes, que incluye también al Setenario.; There is a figural or typological nexus between the historical event told in Cantigas de Santa María 205 and a fragment of the Estoria de España, both alphonsine works which are not usually studied in connection. This feature, which is only a sample of the rich use of typology in the cancionero, is an evidence of an intended symbolic («allegorical») recovery and overcoming of the pagan past, in the wider context of alphonsine texts, including also Setenario.

Control of citrus black spot on lemons with Amistar, Comet, and Flint, 2002/03. Fungicide and Nematicide Tests Fogliata, G. M.; Ploper, Leonardo Daniel; Canton, Norma Virginia; Galvez, M. R.; Muñoz, L. This experiment was conducted in a 6-yr old Lisbon lemon grove in Macomitas, Tucumán, Argentina.  Within a 4-application program, one or two strobilurin applications at different times were included in combination with Dithane or Caurifix, completing the program with the mixture Caurifix plus Dithane.  Treatments were arranged in a randomized complete block design with four replications.  Each plot consisted of three trees. Fungicide applications started at petal fall and continued every 4 weeks for 4 months.  The grower treatment was considered the chemical control standard.  Sprays were made with a conventional high volume sprayer fitted with a handgun, at a pressure of 500 psi using 25 L/tree.  The first important rains began in October after petal fall.  Favorable conditions for infection prevailed from petal fall (October) to December, with rainfall totaling 368 mm, maximum relative humidity over 90%, and average temperatures higher than 18 ºC.  Two evaluations of citrus black spot (CBS) were made when fruits were harvested for the fresh fruit export market (19 May 03 and 22 Jun 03).  Disease incidence was determined in fruits from the center tree of each plot.  A total of 2,000 fruits was evaluated for each treatment. CBS incidence is presented as the average of both harvests.  Environmental conditions favored CBS.  All treatments significantly reduced CBS incidence.  No differences in CBS incidence were detected among the 3 strobilurins in the treatments that included 2-strobilurin applications, and all of these treatments were more effective for CBS control than the grower treatment.  The 3 strobilurins performed differently  in the treatments where only one spray of  strobilurins was included. Comet was more effective than the grower treatment in 3 of the 4 treatments evaluated, in combination with Caurifix at 60 or 90 days after petal fall (apf) and in combination with Dithane at 90 days apf. Comet had  the same CBS incidence as the grower treatment when applied with Dithane at 60 days apf.  The Flint treatments varied according to the other fungicide included in the combination. The two Flint treatments where the fungicide was applied with Caurifix were more effective than the grower treatment. No difference was detected between applications made 60 or 90 days afp.  The mixture Flint-Dithane showed the same CBS incidence as the grower treatment at 60 or 90 days apf.  The performance of Amistar  varied according to the timing of the application; it was more effective than the grower treatment when applied at 60 days apf in combination with either Caurifix or Dithane.  When this fungicide was applied at 90 days apf, the CBS incidence was similar to the grower treatment, with either Caurifix or Dithane. These results indicate that a one application of strobilurins significantly decreases CBS incidence compared to the grower treatment, but that the performance is influenced by the timing of application and fungicide included in the mixture.