Estructura interna de la franja migmatítica del núcleo cristalino de las Sierras Pampeanas Septentrionales del norte argentino; Internal structure of the migmatitic belt in the crystalline core of the northern Sierras Pampenas Northwestern Argentina Cisterna, Clara Eugenia; Mon, Ricardo; Mena, Rodolfo El Complejo Las Cañas (LCC), en la sierra de Aconquija (Sierras Pampeanas Septentrionales, NO de Argentina) está integrado por rocas del basamento cristalino, representadas por migmatitas y en menor proporción por esquistos, que se hallan como resistatos ellas. Las migmatitas varían desde metatexitas a diatexitas y muestran una foliación gnéisica, acompañada de pliegues intrafoliales formados bajo condiciones de elevado metamorfismo, con fusión parcial y anatéxis. La sobreimpresión de un segundo plegamiento genera figuras de interferencia, ante condiciones de elevada ductilidad de los materiales plegados. Finalmente, se reconoce un episodio de deformación por cizallamiento dúctil, que afecta heterogéneamente a las migmatitas. Las observaciones de campo, estructurales y petrográficas permiten definir sobre estas rocas episodios pre, sin y post deformacionales y hacer interpretaciones sobre la evolución del basamento cristalino del noroeste de Argentina.; The Las Cañas Complex located in Aconquija Range (Sierras Pampeanas Septentrionales) is formed by rocks of the crystalline basement, mainly migmatites and, in smaller proportion, schists which are as resisters included in the migmatites. The migmatites range from metatexites to diatexites. They show a migmatitic foliation accompanied by intrafoliated folds generated under high metamorphic conditions, with partial melt and anatexis. A later superposed folding episode under high ductile conditions generated interference patterns. Finally a brittle-ductile shear episode involving the migmatites is recognized. It affects some portions more intensively than others; its distribution is not uniform. The structural and petrographic observations in the field and in microscope allow the recognition of pre, syn and post migmatization deformation episodes. This tectonic evolution occurred along a significant stretch of the crystalline basement of NW Argentina in a mobile belt along the west border of supercontinent Gondwana, where the recognized deformation episodes correspond to the Pampean Orogeny (550 - 500 Ma) and to the superposed Famatinian Orogeny (500 - 440 Ma).

Algunos comentarios sobre muestreo de Poblaciones Bernoulli Lencina, Viviana Beatriz En este trabajo se aborda el problema de Inferencia en Poblaciones Bernoulli, y se muestra cómo, en el proceso de obtener los datos de la población mediante un muestreo aleatorio simple, diferentes fuentes de variabilidad producen parámetros en las variables aleatorias que serán observadas (muestra) que pueden no coincidir directamente con los parámetros en la población bajo estudio.

Habilidades sociales y contexto sociocultural: Un estudio con adolescentes a través de la BAS-3; Social skills and sociocultural context: A study with adolescents through the BAS-3 Cohen Imach, Silvina; Esterkind de Chein, Ana Helena; Lacunza, Ana Betina; Caballero, Silvina Valeria; Martinenghi, Constanza El estudio tiene como objetivos: 1) describir las habilidades sociales en adolescentes de 11 y 12 años que viven en contextos de pobreza de Tucumán, Argentina; 2) explorar diferencias en las habilidades sociales en función del género; y 3) analizar la incidencia de variables vinculadas al grupo familiar en las habilidades sociales de los adolescentes estudiados. La muestra está constituida por 194 adolescentes de 11 y 12 años escolarizados de contextos de pobreza. Se trata de un estudio descriptivo realizado a través de la Batería de Socialización BAS-3 (Silva Moreno & Martorell Pallás, 2001) y una encuesta sociodemográfica elaborada por el equipo de investigación. Se analizan las habilidades sociales de los participantes según género y las características del grupo familiar (tipo de familia, posición del sujeto en la fratría, número de hermanos y cantidad de personas que viven en el hogar). En cuanto al género, los resultados señalan que difieren estadísticamente en la escala de Ansiedad social/Timidez, siendo más alta en mujeres que en varones. Respecto de las características de la familia, sólo se encuentra una relación negativa entre números de hermanos y la escala de Liderazgo. No se registran diferencias con respecto a las otras características del grupo familiar.; The study aims to: 1) describe social skills in adolescents of 11 to 12 years living in poverty contexts of Tucuman, Argentina, 2) analyze the social skills of participants by gender and 3) analyze the impact of variables related to the family in the social skills of adolescents studied. The sample consisted of 194 adolescents aged 11 and 12 years from schools in contexts of poverty. This is a descriptive study through Socialization Battery BAS-3 (Silva Moreno & Martorell Pallas, 2001) and a demographic survey developed by the research team. We analyze the social skills of participants by gender and household characteristics (family type, adolescent’s position in the sibling group, number of siblings and number of people living at home). In gender terms, the results show that differ statistically at the level of Social anxiety / shyness, being higher in females than in males. Regarding the characteristics of the family, is only a negative statistical relation between numbers of siblings and the scale of Leadership. No significant differences with respect to other characteristics of the household.

Screaming Cowbird parasitism on nests of Solitary Caciques and Cattle Tyrants Di Giacomo, Alejandro G.; Mahler, Bettina; Reboreda, Juan Carlos The Screaming Cowbird (Molothrus rufoaxillaris) is one of the most specialized brood parasites with only three known hosts: Baywing (Agelaioides badius), the main host throughout most of its range, and two alternative hosts in some areas of its distribution, Chopi Blackbird (Gnorimopsar chopi) and Brown-and-yellow Marshbird (Pseudoleistes virescens). We studied Screaming Cowbird parasitism in northeast Argentina where this parasite uses Baywings and Chopi Blackbirds as hosts. We monitored 69 nests of Baywings, 251 of Chopi Blackbirds, 31 of Solitary Caciques (Cacicus solitarius), and 30 of Cattle Tyrants (Machetornis rixosa). The frequency of Screaming Cowbird parasitism on Baywing nests was 80% and was 46% for Chopi Blackbirds. We recorded one event of Screaming Cowbird parasitism on one nest of Solitary Caciques and three events of Screaming Cowbird parasitism on one nest of Cattle Tyrants. The identities of parasitic eggs in both hosts were confirmed by sequencing the mtDNA control region. We propose these events of parasitism resulted from recognition errors by Screaming Cowbird females that regularly parasitize Baywings and Chopi Blackbirds. The nest of Solitary Caciques had been frequently visited by a pair of Baywings before Screaming Cowbird parasitism occurred, and the nest of Cattle Tyrants was near an active Chopi Blackbird nest that had been previously parasitized by Screaming Cowbirds.

The adsorption of 1,3-butadiene on Pd/Ni multilayers: The interplay between spin polarization and chemisorption strength Gómez, Guillermina; Belelli, Patricia Gabriela; Cabeza, Gabriela Fernanda; Castellani, Norberto Jorge The adsorption of 1,3-butadiene (BD) on the Pd/Ni(1 1 1) multilayers has been studied using the VASP method in the framework of the density functional theory (DFT). The adsorption on two different configurations of the Pd n/Nim(1 1 1) systems were considered. The most stable adsorption sites are dependent on the substrate composition and on the inclusion or not of spin polarization. On Pd1Ni3(1 1 1) surface, diπcis and 1,2,3,4-tetra-σ adsorption structures are the most stable for non-spin polarized (NSP) and spin polarized (SP) levels of calculation, respectively. Conversely, on Pd3Ni1(1 1 1) surface, the 1,2,3,4-tetra-σ adsorption structure is the most stable for both NSP and SP levels, respectively. The magnetization of the Pd atoms strongly modifies the adsorption energy of BD and its most stable adsorption mode. On the other hand, as a consequence of BD adsorption, the Pd magnetization decreases. The smaller adsorption energies of BD and 1-butene on the Pd1Ni3(1 1 1) surface than on Pd(1 1 1) can be associated to the strained Pd overlayer deposited on Ni(1 1 1).

Self-assembled multilayers of polyethylenimine, DNA and gold nanoparticles. A study of electron transfer reaction Ferreyra, Nancy Fabiana; Bollo, Soledad; Rivas, Gustavo Adolfo The present manuscript describes studies of the electron transfer kinetics at gold electrodes modified by electrostatic self-assemblies of polyethylenimine (PEI), DNA and gold nanoparticles (NP) by Scanning Electrochemical Microscopy (SECM). Two redox mediators of similar structure, ferrocenemethanol (FcOH), and ferrocenecarboxylic acid (FcCOOH) were used to evaluate the effect of the electrode modification on the electron transfer process. For both redox probes, the observed electrochemical behavior was dependent of the charge of the external layer of the self-assembled structure. The corresponding apparent heterogeneous rate constant, k0, was determined. The effect of NP adsorption was also evaluated. Independently of the mediator used, an increase of the k0 was observed when NPs were incorporated, and the surfaces presented a conductive behavior similar to the bare gold electrode. SECM images using FcOH as redox mediator were also recorded. Variations in the normalized currents permitted to evaluate differences of the surface electroactivity due to the polymers and/or nanoparticles adsorption. © 2009 Elsevier B.V. All rights reserved.

Ultrasensitive detection of nitrogen oxides over a nanoporous membrane Prabhakar, Amlendu; Iglesias, Rodrigo Alejandro; Wang, Rui; Tsow, Francis; Forzani, Erica S.; Tao, Nongjian A nitrogen oxide (NOx; x = 1, 2) optical sensor with an extremely low detection limit in the range of fractions of ppbV (0.3 ppbV for 20 s sample injection) is presented. Phenylenediamine derivatives are utilized as molecular probes in the solid state on a nanoporous membrane to produce a miniaturized and low cost sensing platform for use as a wearable personal monitor.

Study of the water-gas shift reaction over Pt supported on CeO 2-ZrO2 mixed oxides Vignatti, Charito Ivana; Avila, Maria Sol; Apesteguia, Carlos Rodolfo; Garetto, Teresita Francisca The water gas shift (WGS) reaction was studied on Pt/CeO2, Pt/ZrO2 and Pt/CexZr1-xO2 catalysts. All the samples were characterized by a variety of physical and spectroscopic techniques. The catalyst activities were evaluated at 250 °C in a recirculating reactor through CO conversion versus time tests and also by in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). The sample activity for the WGS reaction depended on chemical composition. Pt/CexZr1-xO2 catalysts with x ≥ 0.5 were more active than Pt/CeO2, probably because the addition of Zr to ceria increased both the surface area and the reducibility of ceria. The lowest CO conversion rates were obtained on Pt/ZrO2 and Zr-rich Pt/Ce xZr1-xO2 samples. Based on DRIFTS experiments, this result was interpreted by considering that in the WGS formate associative mechanism the stability of formate species is higher on Zr-rich supports.

Novel binderless zeolite-coated monolith reactor for environmental applications Zamaro, Juan Manuel; Miro, Eduardo Ernesto A novel structured catalyst based on a binderless zeolite film was developed onto a cordierite monolith. The zeolitic film was obtained performing a binderless washcoating which was followed by a hydrothermal treatment, which resulted in a coating with hybrid physicochemical properties, having a porous washcoat-like microstructure with an intergrowth between the aggregates. This combination confers to the zeolite coating an open structure which is an advantage of washcoats and a high mechanical stability characteristic of the zeolite growths. It should be emphasized that these desired properties are obtained without the use of binders. The physico-chemical properties were investigated through MIP (mercury intrusion porosimetry), SEM (scanning electron microscopy), ultrasonic adherence tests, NO-TPD (temperature-programmed desorption of NO) and EPMA (electron probe microanalysis). The catalytic properties of the monolith were evaluated in the selective catalytic reduction of NOx at high spatial velocities, showing promising results.

Insecticidal, Mutagenic and Genotoxic Evaluation of Annonaceous Acetogenins Álvarez Colom, Olga; Salvatore, Silvana Analia; Willink, Eduardo; Ordóñez, Roxana Mabel; Isla, Maria Ines; Neske, Adriana Neske; Bardon, Alicia del Valle Annonaceous acetogenins represent a class of bioactive compounds whose primary mode of action is the inhibition of NADHubiquinone oxidoreductase (Mitochondrial Complex I). Given the potential pesticidal use of these compounds, we evaluated the effects of seven acetogenins: squamocin (1), molvizarin (2), itrabin (3), almuñequin (4), cherimolin-1 (5), cherimolin-2 (6), and tucumanin (7) isolated from Annona cherimolia Mill. against Ceratitis capitata Wiedemann (Tephritidae). These acetogenins did not display insecticidal action at 250 µg of treatment per g of adult diet. However, the oviposition capacity of C. capitata females was significantly altered by some of the acetogenins at this concentration. The most potent compounds were itrabin, molvizarin and squamocin. Moreover, significant differences were detected in the preference of oviposition sites when itrabin and squamocin were spread on the surface of artificial fruits at doses of 30 µg/cm2 . Additionally, we investigated the mutagenic effects displayed by itrabin, as well as the phytotoxic and genotoxic action of squamocin and itrabin. Both compounds displayed slight phytotoxic and genotoxic effects on roots of Allium cepa at 2.5 µg/mL though no mutagenic effects were detected at 0.25, 0.5 and 2.5 µg/mL on Salmonella typhimurium strains TA98 and TA100.

Stenomicra (Diptera: Opomyzoidea) in Argentina, with information on the biology of the genus; Stenomicra (Diptera: Opomyzoidea) en Argentina, con información sobre la biología del género Campos, Raul Ernesto; Gramajo, Maria Cecilia; Lizarralde, Mercedes Sara This is the first literature record of the genus Stenomicra Coquillett (Diptera: Periscelididae) from South America (Neotropical Region). New information on the biological cycle of Stenomicra species in the wild is provided, and four species of the genus Eryngium L. (Apiaceae) are recorded as host plants for immature stages of this taxon. The specimens of Stenomicra sp. were collected in Sierra de la Ventana, Buenos Aires province, Argentina.; En este estudio, se publica por primera vez para Sudamérica (Región Neotropical) el género Stenomicra Coquillett (Diptera: Periscelididae). Se aporta información sobre su ciclo biológico en condiciones naturales y se mencionan cuatro especies del género Eryngium L. (Apiaceae), como plantas hospedadoras de los estados inmaduros. Los ejemplares de Stenomicra sp. fueron colectados en Sierra de la Ventana, Provincia de Buenos Aires, Argentina.

On the estimation of the cost of equity in Latin America Grandes, Martin; Panigo, Demian Tupac; Pasquini, Ricardo Aníbal This paper researches the sources of stock market risk influencing the pricing of 921 Latin American stocks and computes their corresponding opportunity cost (COE) over the period 1997–2004 by firm and sector. Running an adjusted version of the Capital Asset Pricing Model (CAPM) it finds that systematic risk accounts on average for more than 32% of COE total variance. This implies that potential CAPM mispricing related to undiversified idiosyncratic risk in Latin America has been relatively lower (but absolutely higher) than in United States and other European and Asian stock markets (such as the United Kingdom, Canada or Japan). A first robustness test for the omission of international sources of un-diversifiable risk suggests that both global market and real currencies portfolios do not add significant information to domestic market portfolios. Moreover, a second robustness check offers further evidence that well-diversified portfolios constructed by sorting stocks according to their size and book-to-market ratios a la Fama and French do not improve the goodness of fit in the regressions based on the adjusted version of CAPM.

Anisotropy of the Taylor scale and the correlation scale in plasma sheet magnetic field fluctuations as a function of auroral electrojet activity Weygand, James M.; Matthaeus, W. H.; El Alaoui, M.; Dasso, Sergio Ricardo; Kivelson, M. G. Magnetic field data from the Cluster spacecraft in the magnetospheric plasma sheet are employed to determine the correlation scale and the magnetic Taylor microscale from simultaneous multiple‐point measurements for multiple intervals over a range of mean magnetic field directions for three different levels of geomagnetic activity. We have determined that in the plasma sheet the correlation scale along the mean magnetic field direction decreases from 19,500 ± 2200 to 13,100 ± 700 km as the auroral electrojet activity increases from quiet (<80 nT) to active conditions (>200 nT). The reverse occurs for the correlation scale perpendicular to the magnetic field, which increases from 8200 ± 600 km to 13,000 ± 2100 km as the auroral electrojet activity increases from quiet to active conditions. This variation of the correlation scale with geomagnetic activity may mean either a change in the scale size of the turbulence driver or may mean a change in the predominance of one over another type of turbulence driving mechanism. Unlike the correlation scale, the Taylor scale does not show any clear variation with geomagnetic activity. We find that the Taylor scale is longer parallel to the magnetic field than perpendicular to it for all levels of geomagnetic activity. The correlation and Taylor scales may be used to estimate the effective magnetic Reynolds numbers separately for each angular channel. Reynolds numbers were found to be approximately independent of the angle relative to the mean magnetic field. These results may be useful in magnetohydrodynamic modeling of the magnetosphere and can contribute to our understanding of energetic particle diffusion in the magnetosphere.

Increased nitration and diminished activity of copper/zinc superoxide dismutase in placentas from diabetic rats White, Verónica; Capobianco, Evangelina Lorena; Higa, Romina Daniela; Martinez, Nora Alicia; Sosa, María; Jawerbaum, Alicia Sandra Nitration-induced protein damage in the placenta leads to impaired blood flow and deficient feto–placental exchange in diabetic pregnancies. This work studied the effect of nitric oxide and peroxynitrite on Cu/Zn SOD activity in rat placentas and evaluated whether Cu/Zn SOD is nitrated in the placenta from diabetic rats at mid-gestation. Protein nitration was evaluated by EIA, Cu/Zn SOD activity by inhibition of the epinephrine auto-oxidation, Cu/Zn SOD expression by western blot and specific nitration by immunoprecipitation. This study found higher levels of protein nitration (p < 0.001), diminished Cu/Zn SOD activity and enhanced protein expression (p < 0.01) in placentas from diabetic rats. Placental Cu/Zn SOD activity was inhibited by peroxynitrite (p < 0.01). Besides, nitration of Cu/Zn SOD was elevated in placentas from diabetic rats (p < 0.01). These results show that rat Cu/Zn SOD can be nitrated, a modification that could lead to the depressed activity of this enzyme found in placentas from diabetic rats.

Ambientación y aplicación variable de insumos en áreas con influencia freática Nosetto, Marcelo Daniel; Jobbagy Gampel, Esteban Gabriel; Mercau, Jorge L. El manejo por ambientes es muy útil para aumentar la eficiencia de producción en campos con influencia freática. El aporte de napas a los cultivos puede determinar altos rendimientos y reducir el riesgo hídrico en ambientes semiáridos o subhúmedos.

Experiencia didáctica en el aula de ciencia: el suelo como integrador de conceptos químicos; Teaching experience in the classroom of science: the soil as chemical thread concept Moro, Lucrecia E.; Tintori Ferreira, María Alejandra; Lorenzo, Maria Gabriela En este trabajo presentamos una propuesta didáctica innovadora para alumnos de la Educación Secundaria, sobre le tema suelo en la cual se tiene en cuenta el impacto de la actividad humana. Esta propuesta se implementó durante el desarrollo del tema disoluciones y ofreció una nueva alternativa para la interpretación de los conceptos de disolución y de pH. Se relacionaron los compuestos químicos con los agentes formadores del suelo y sus contaminantes. La experiencia didáctica se desarrolló simultáneamente en cinco escuelas de la Provincia de Buenos Aires empleando una metodología “en red” en el marco del Programa “Ciencia entre Todos” (CET). Presentamos la propuesta didáctica por su carácter innovador para el tratamiento de los diseños curriculares de química, por su enfoque integrador con las problemáticas sociales de la región y la promoción del cuidado del ambiente desde el punto de vista del desarrollo sustentable.; We present a new didactic approach for secondary students about “the soil”. The impact of the human activity was especially considered. This design was carried out for solutions and provided new strategies for understanding pH concept. Chemical compounds were related with the training agents of the ground and its pollutant. This didactic experience was simultaneously put into practice in five schools of Provincia de Buenos Aires employing net methodology. This belongs to the Program “Science by and for Everyone” (CET). We present this proposal because of its innovation characteristics for chemical contents, its focus on social and regional problems and the promotion of environment care from sustainable development perspective.

Recombinant horseradish peroxidase production in species of lepidoptera frequently found in Argentina Romero, Lucía Virginia; Targovnik, Alexandra Marisa; Wolman, Federico Javier; Fogar, M.; Simonella, M.; Cascone, Osvaldo; Miranda, Maria Victoria Horseradish peroxidase isozyme C (HRPC) is an important commercial biocatalyst. In this study, a screening of different lepidopteran species frequently found in Argentina to produce this protein was carried out. Two recombinant viruses were constructed: AcMNPV HRPC polyhedrin-minus (occ−), an intrahemocelical infective virus; and AcMNPV HRPC polyhedrin-plus (occ+), to achieve an oral infective baculovirus. Each lepidopteran species was infected either with AcMNPV HRPC occ− or AcMNPV HRPC occ+ and the harvesting days post-infection (dpi) were optimized. All species were susceptible to AcMNPV HRPC occ− infection, giving Spodoptera frugiperda the best yield: 41 μg per larva. Rachiplusia nu was highly susceptible to oral infection, reaching 22 μg per larva at 4 dpi. HRPC was purified by IMAC from S. frugiperda extracts with a yield of 86% and a purification factor of 29.

Factores que afectan el éxito reproductivo y la calidad de la nidada del pingüino patagónico (Spheniscus Magellanicus) en el Canal Beagle, Tierra del Fuego, Argentina; Factors affecting reproductive success and clutch quality of Magellanic Penguin (Spheniscus Magellanicus) in the Beagle Channel, Tierra del Fuego, Argentina Scioscia, Gabriela; Raya Rey, Andrea Nélida; Favero, Marco; Schiavini, Adrian Carlos Miguel En este estudio se estimó la duración de los viajes de alimentación y el tamaño corporal de machos y hembras del pingüino patagónico durante el período reproductivo en una colonia del Canal Beagle, Tierra del Fuego, y se determinaron las implicancias de estos parámetros sobre el éxito reproductivo y la calidad de la nidada. La duración de los viajes difirió significativamente entre sexos y entre las distintas etapas reproductivas. Las hembras realizaron viajes más extensos que los machos durante la etapa de incubación. Esto podría deberse a diferencias en las reservas corporales y en capacidades de alimentación relacionadas con su condición corporal. En ambos sexos, los viajes realizados durante la etapa de incubación fueron más prolongados, mientras que los realizados durante el cuidado temprano de pichones fueron más cortos. Los viajes de alimentación tuvieron menor duración cuando los pichones eran más pequeños y necesitaban de un mayor cuidado parental. Se registró un alto valor de éxito reproductivo (1.51 pichones por nido) comparado con el de colonias de las Islas Malvinas y Punta Tombo. Estos resultados podrían explicarse por diferencias en la disponibilidad de alimento en aguas cercanas a la colonia. El tamaño corporal de los padres no se relacionó con el éxito reproductivo. No obstante, las hembras con mayor tamaño corporal produjeron pichones de mayor tamaño al comienzo de la muda y nidadas de mayor calidad. La correlación positiva entre el tamaño de la hembra y el tamaño de los pichones al comienzo de la muda sugiere un aporte importante de las hembras en el desarrollo del pichón.; The aim of this work was to study foraging trip duration and body size of male and female Magellanic Penguins during the breeding season and to determine the association of these parameters with both reproductive success and clutch quality in a colony located in the Beagle Channel, Tierra del Fuego. Trip duration differed significantly between sexes and between breeding stages. Females performed longer trips than males during incubation. We suggest that this could be due to differences in body reserves and foraging capabilities related with their body condition. In both sexes, foraging trips during incubation were longer than in the other stages, while the shortest trips were observed during early chick rearing. Trips were shorter when chicks were smaller and required greater parental care. A high value of reproductive success (1.51 chicks per nest) was recorded in comparison to that observed in colonies from the Malvinas Islands and Punta Tombo. These results could be related to differences in food availability in nearby waters. Body size of parents was not associated with reproductive success. Notwithstanding, larger females produced larger chicks at early moult and clutches of higher quality. The correlation between female body size and chick size at early moult suggests an important contribution of females on chick's development.

Synthesis and Characterization of superparamagnetic Iron Oxide Nanoparticles for bio-medical applications Cano, Leonardo Andres; Cagnoli, Maria Virginia; Stewart, Silvana Jacqueline; Cabanillas, Edgardo Domingo; Romero, E. L.; Marchetti, Sergio Gustavo Monodisperse iron oxide nanoparticles (NPs) of 4 nm were obtained through high-temperature solution phase reaction of iron (III) acetylacetonate with 1, 2-hexadecanediol in the presence of oleic acid and oleylamine. The as-synthesized iron oxide nanoparticles have been characterized by X-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy and magnetic measurements. The species obtained were Fe3O4 and/or γγ -Fe2O3. These NPs are superparamagnetic at room temperature and even though the reduced particle size they show a high saturation magnetization (MS ≈ 90 emu/g).

As estatísticas como objeto de estudo González Bollo, Hernán Gustavo De 12 a 15 de novembro de 2010, a “Sociedade Brasileira de História da Ciência” (SBHC), estará promovendo seu 12º Seminário Nacional de História da Ciência e da Tecnologia, na cidade de Salvador, nas dependências da Universidade Federal da Bahia. Junto, tendo por objetivo precípuo a reativação da “Sociedade Latino-Americana de História da Ciência e da Tecnologia”, estará sendo realizado seu 7º Congresso. Pois este ano, pela primeira vez, haverá um simpósio focalizando as estatísticas como objeto de estudo, e não como meio de análise: “As instituições estatísticas oficiais: conceitos, medições, comunidades profissionais e a criação de políticas públicas”. Foi uma idéia de Nelson de Castro Senra, que logo recebeu aceitação entusiástica de Hernán González Bollo, quando, então, ambos passaram a trabalhar em colaboração, elaborando a proposta enviada à SBHC.