Actividad sanguínea de superóxido dismutasa y glutatión peroxidasa en novillas a pastoreo

El objetivo de este estudio fue determinar el balance metabólico nutricional de Cu, Zn, Fe, Mn y Se, mediante la actividad sanguínea de SOD y GSH-Px y establecer la relación entre la concentración de Cu, Fe, Mn y Zn en el forraje y la actividad de SOD. Se tomaron 10 mL de sangre a 105 novillas seleccionadas en 15 rebaños lecheros de Caldas, Colombia (5º4' N y 75º3' O) y se tomaron muestras de forrajes para analizar Cu, Fe, Mn y Zn. El promedio de la actividad de SOD fue 1.390±1.299 U g-1 Hb, y estaba correlacionada con Cu, Mn y Fe en el forraje. La actividad promedio de GSH-Px fue 389±184 U g-1 Hb y fue observada una mayor frecuencia de valores deficitarios y bajo/marginales de 9%, habiendo sido más afectados los animales de zonas altas (>2.000 msnm). Bajo estas condiciones, estos resultados permiten señalar que la SOD es una enzima que puede emplearse como indicador del balance metabólico nutricional de Cu, Mn y Fe en bovinos a pastoreo, no está clara todavía su relación con Zn. La actividad de GSH-Px indica deficiencias en el balance metabólico nutricional de Se, en bovinos a pastoreo.

Iniciativas de gestión pública que promueven la productividad desde una perspectiva del género

Este trabajo es un análisis crítico de la gestión organizacional que estudia la participación de la mujer en formatos productivos locales en dos regiones: la provincia de Santa Fe en Argentina y en las regiones rurales de la Zona Central de Chile. Ambos análisis exponen una visión acerca del riesgo del retorno de la inversión del capital socio-económico en formatos productivos de desarrollo local que son afectados por intervenciones de la administración de políticas públicas en el ámbito de la mujer. Este trabajo constituye un análisis cualitativo descriptivo y de proceso heurístico sobre la visión que se tiene del género, y particularmente de la mujer, para entender qué tipos iniciativas estimulan la participación hacia esa forma de organización de trabajo de coproducción y bajo qué condiciones estas ocurren.

La meditación en la Luz Sai Baba como performance ritual: acceso corpóreo-experimental a dios

Este artigo descreve e analisa uma prática característica de grupos argentina devotos de Sai Baba, também conhecida como Meditação na Luz. Caracterizamos-a como uma performance ritual onde, também, encontramos representações simbólicas em torno á corporalidade que chamamos geografia corporal. Examinamos como se constrói a eficácia ritual em dita pratica, e se argumenta que esta performance é eficaz porque contribui para modificar a pessoa á lograr seu objetivo espiritual fundamental (a fusão com Deus). Neste ponto, contrastamos este tipo de meditação com as clássicas meditações metafísicas cartesianas. Finalmente, destaca se a relevância da inclusão da dimensão corporal performática na analise dos fenômenos religiosos.

Trypanocide treatment among adults with chronic Chagas disease living in Santa Fe city (Argentina), over a mean follow-up of 21 years: parasitological, serological and clinical evolution

The efficacy of treatment with nifurtimox and/or benznidazole among adults with chronic Chagas disease with no previous electrocardiographic disturbances was evaluated over a mean follow-up of 21 years, by means of conventional serology, xenodiagnosis, clinical examination, electrocardiograms and chest X-ray. One hundred and eleven patients, between 17 and 46 years old, were studied: 54 underwent treatment (nifurtimox 27, benznidazole 27) and 57 remained untreated (control group). Xenodiagnosis was performed on 65% of them: 36/38 of the treated and 9/34 of the untreated patients had previous positive xenodiagnosis. Post-treatment, 133 xenodiagnoses were performed on 41 patients, all resulting negative. In the control group, 29 xenodiagnoses were performed on 14 patients; 2 resulted positive. Sera stored during the follow-up were simultaneously analyzed through conventional serology tests (IHA; DA-2ME; IIF). The serological evolution in the treated group was: a) 37% underwent negative seroconversion (nifurtimox 11, benznidazole 9); b) 27.8% decreased titers (nifurtimox 9, benznidazole 6), 9 showed inconclusive final serology (nifurtimox 7, benznidazole 2); c) 35.2% remained positive with constant titers (nifurtimox 7; benznidazole 12). The control group conserved the initial antibody levels during the follow-up. In the clinical evolution, 2/54 (3.7%) of the treated and 9/57 (15.8%) of the untreated patients showed electrocardiographic disturbances attributable to Chagas myocardiopathy, with a statistically relevant difference (p<0.05). Treatment caused deparasitation in at least 37% of the chronically infected adults and a protective effect on their clinical evolution.

Serological detection of St. Louis encephalitis virus and West Nile virus in equines from Santa Fe, Argentina

St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) present ecological and antigenic similarities and are responsible for serious human diseases. In addition, WNV is a significant pathogen in terms of equine health. The purpose of our study was to analyse the seroprevalence of SLEV and WNV in equine sera collected in Santa Fe Province, Argentina. The seroprevalence determined using the plaque reduction neutralisation test was 12.2% for SLEV, 16.2% for WNV and 48.6% for a combination of both viruses. These results provide evidence of the co-circulation of SLEV and WNV in equines in Santa Fe.

Mortality of Plutella xylostella (Lepidoptera, Plutellidae) by parasitoids in the Province of Santa Fe, Argentina

Mortality of Plutella xylostella (Lepidoptera, Plutellidae) by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae), in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae), L3 (Lm = medium larvae), L4 (Ll = large larvae), pre-pupae and pupae (P). Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875) (Hymenoptera, Ichneumonidae), Oomyzus sokolowskii (Kurdjumov, 1912) (Hymenoptera, Eulophidae), Cotesia plutellae (Kurdjumov, 1912) (Hymenoptera, Braconidae) and an unidentified species of Chalcididae (Hymenoptera). Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.

Activity of phosphorus of synthetic Fe-K-P compounds in superphosphate fertilizers as affected by pH and ionic strength

The concentration of orthophosphate ions released from Fe-K-P compounds (Fe3KH8(PO4)6 .6H2O and Fe3KH14(PO4)8 .4H2O) present in superphosphates increases with pH, which initially suggests that the agronomic effectiveness of P fertilizers containing high amounts of these compounds would also increase with soil pH but studies considering activity, instead of concentration, are necessary. With this purpose, both compounds were synthesized under laboratory conditions, characterized by elemental chemical analysis, optical microscopy, X ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and used in a solubility study. Solutions of 0.01, 0.05 and 0.1 mol L-1 NaCl with pH adjusted to 3.0, 4.0, 5.0, 5.5, 6.0, 6.5, 7.0 and 7.5 were prepared for the solubility study of H8-syn, H14-syn and a phosphate rock (PR) from Brazil. The orthophosphate activity as H2PO4- and HPO4(2-) was calculated in each situation as related to pH and ionic strength using software MINTEQ. The remaining precipitates after equilibrium were chemically analyzed and subjected to X ray, SEM and EDS. Results of chemical analysis and instrumental techniques confirmed the preparation method. The activity of orthophosphate ions of both compounds tended to decrease under increasing pH and/or ionic strength of the solution, which in turn suggests that an increase in the solution pH does not necessarily promote an increase in the P bioavailability for plant uptake. This can be important when evaluating agronomic data of P fertilizers with high contents of these two Fe-K-P compounds.

Nickel incorporation in Fe(II, III) hydroxysulfate Green Rust: effect on crystal lattice spacing and oxidation products

Ni(II)-Fe(II)-Fe(III) layered double hydroxides (LDH) or Ni-containing sulfate green rust (GR2) samples were prepared from Ni(II), Fe(II) and Fe(III) sulfate salts and analyzed with X ray diffraction. Nickel is readily incorporated in the GR2 structure and forms a solid solution between GR2 and a Ni(II)-Fe(III) LDH. There is a correlation between the unit cell a-value and the fraction of Ni(II) incorporated into the Ni(II)-GR2 structure. Since there is strong evidence that the divalent/trivalent cation ratio in GR2 is fixed at 2, it is possible in principle to determine the extent of divalent cation substitution for Fe(II) in GR2 from the unit cell a-value. Oxidation forms a mixture of minerals but the LDH structure is retained if at least 20 % of the divalent cations in the initial solution are Ni(II). It appears that Ni(II) is incorporated in a stable LDH structure. This may be important for two reasons, first for understanding the formation of LDHs, which are anion exchangers, in the natural environment. Secondly, this is important for understanding the fate of transition metals in the environment, particularly in the presence of reduced Fe compounds.

Induction of a geochemical barrier for As, Fe and S immobilization in a sulfide substrate

Acid mine drainage (AMD) is an environmental concern due to the risk of element mobilization, including toxic elements, and inclusion in the food chain. In this study, three cover layers were tested to minimize As, Fe and S mobilization from a substrate from former gold mining, containing pyrite and arsenopyrite. For this purpose, different layers (capillary break, sealant and cover layer) above the substrate and the induction of a geochemical barrier (GB) were used to provide suitable conditions for adsorption and co-precipitation of the mobilized As. Thirteen treatments were established to evaluate the leaching of As, Fe and S from a substrate in lysimeters. The pH, As, Fe, S, Na, and K concentrations and total volume of the leachates were determined. Mineralogical analyses were realized in the substrate at the end of the experimental period. Lowest amounts of As, Fe and S (average values of 5.47, 48.59 and 132.89 g/lysimeter) were leached in the treatments that received Na and K to induce GB formation. Mineralogical analyses indicated jarosite formation in the control treatment and in treatments that received Na and K salts. However, the jarosite amounts in these treatments were higher than in the control, suggesting that these salts accelerated the GB formation. High amounts of As, Fe and S (average values of 11.7, 103.94 and 201.13 g/lysimeter) were observed in the leachate from treatments without capillary break layer. The formation of geochemical barrier and the use of different layers over the sulfide substrate proved to be efficient techniques to decrease As, Fe and S mobilization and mitigate the impact of acid mine drainage.

Cambios en la vegetacion de un campo abandonado despues de un cultivo de trigo

La vegetación prístina de los campos altos del sur de Santa Fe (Argentina) son distintos tipos de flechillares caracterizados por la abundancia de varias especies del género Stipa. Cuando un campo agrícola se abandona suele revertir a las comunidades prístinas. El objeto de este trabajo es analizar los diez primeros años de la sucesión secundaria de un campo sometido a agricultura durante largo tiempo que se abandonó después de un cultivo de trigo (Triticum aestivum). En el primer año aparece trigo acompañado de malezas anuales (Chenopodium album y Portulaca oleracea); después del primer año una parcela fue colonizada por Baccharis salicifolia y las otras por Carduus acanthoides, Cerastium glomeratum, Ammi majus, etc. Los últimos años constituyen una etapa en la que disminuye la diversidad y se establece una fuerte dominancia de Baccharis salicifolia o Carduus acanthoides. El Sorgo de Alepo (Sorghum halepense) aparece en las etapas tempranas y perdura durante todo el período con valores altos de abundancia. Aún, prácticamente no han aparecido especies de los flechillares, por lo tanto se concluye que no ha transcurrido suficiente tiempo para que se regenere el flechillar, o porque sus especies no se encuentran en los bancos de semillas o en las proximidades.

Población de mosca blanca en tomate cultivado a campo con pantallas de sombreamiento

El objetivo de este trabajo fue analizar la población de mosca blanca Trialeurodes vaporariorum, Westwood (Hemiptera: Aleyrodidae) en tomate de verano en cultivos con sombreado, en Santa Fe, Argentina. Se transplantó tomate en hileras cubriendo un sector con malla negra de polipropileno, realizándose cada tres días, en 30 plantas un recuento de adultos en una hoja superior y de ninfas en diez folíolos al azar. El diseño experimental fue de bloques al azar analizándose la correlación entre la temperatura y la evolución de adultos y ninfas. El sombreado disminuyó la temperatura, pero incrementó diez veces la densidad de adultos y cinco veces la de ninfas respecto al cultivo al aire libre.

Novel neutral iron(II) isocyanide maleonitrile dithiolate [Fe(S2C2(CN)2)(t-BuNC) 4] compound

FeBr2 reacts with the S2C2(CN)2(2-) ion (1:1 ratio) in the presence of an excess of t-BuNC in THF to give the mixed ligand [Fe(S2C2(CN)2)(t-BuNC) 4] compound. This neutral product with a formal oxidation state of two for the iron atom was characterized by conductivity measurements, and, i.r., Mössbauer, 13C and ¹H n.m.r. spectroscopy. There is a Fe-C pi back-donation strengthened towards isocyanide ligands, according to the data of 13C, ¹H n.m.r. and Mössbauer spectroscopy.

Synthesis, characterization, DFT and Td-dfT study of the [Fe(mnt)(L)(t-BuNC) 2] octahedral complex (L = phen, bipy)

FeBr2 has reacted with an equivalent of mnt2- (mnt = cis-1,2-dicyanoethylene-1,2-dithiolate) and the α-diimine L (L = 1,10'-phenantroline, 2,2'-bipyridine) in THF solution, and followed by adding of t-butyl-isocyanide to give [Fe(mnt)(L)(t-BuNC)2] neutral compound. The products were characterized by infrared, UV-visible and Mössbauer spectroscopy, besides thermogravimetric and conductivity data. The geometry in the equilibrium was calculated by the density functional theory and the electronic spectrum by the time-dependent. The experimental and theoretical results in good agreement have defined an octahedral geometry with two isocyanide neighbours. The π→π* intraligand electronic transition was not observed for cis-isomers in the near-IR spectral region.

Fe (ii) adsorption on Ucides Cordatus crab shells

In this study Ucides cordatus crab shells were utilized as Fe (II) sorbent as material of low cost and simple preparation. Values of pH of standard solution, biosorbent mass, particles size, contact time (t c) and initial concentration of the standard solution were optimized. The best conditions were pH = 2.00, t c = 840 min and Mc = 0.25 g. The kinetic pseudo first-order model displayed the best description of the adsorption process and the equilibrium study showed that the Langmuir model better describes the adsorption of the Fe (II). There is great affinity between the Fe (II) and the biosorbent.