La producción caprina en La Pampa, ganadería agroecológica, propuestas y necesidades de investigación

Se analizan en este trabajo algunos aspectos de los sistemas de producción caprina del oeste pampeano, puntualizando experiencias tendientes a la sustentabilidad de los mismos dentro del marco de una ganadería agroecológica. Las experiencias relatadas se han desarrollado en el marco de diferentes Programas y Proyectos en los que han participado el INTA, el Ministerio de la Producción de La Pampa, la Secretaría de Agricultura Familiar, la Universidad de La Pampa y crianceros independientes, nucleados en la Asociación de Criadores de la Cabra Colorada Pampeana .Asimismo, se proponen algunas líneas de investigación, especialmente referidas a la recuperación de saberes populares, a la utilización de zooterápicos naturales y de plantas forrajeras nativas y exóticas, como también referidas al manejo del sistema de pastoreo sobre el monte natural, con el fin de disminuir la incidencia de la introducción de insumos como medicamentos y alimentos externos al sistema.Eje B1 Sistemas de producción de base agroecológica (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

La producción caprina en La Pampa, ganadería agroecológica, propuestas y necesidades de investigación

Se analizan en este trabajo algunos aspectos de los sistemas de producción caprina del oeste pampeano, puntualizando experiencias tendientes a la sustentabilidad de los mismos dentro del marco de una ganadería agroecológica. Las experiencias relatadas se han desarrollado en el marco de diferentes Programas y Proyectos en los que han participado el INTA, el Ministerio de la Producción de La Pampa, la Secretaría de Agricultura Familiar, la Universidad de La Pampa y crianceros independientes, nucleados en la Asociación de Criadores de la Cabra Colorada Pampeana .Asimismo, se proponen algunas líneas de investigación, especialmente referidas a la recuperación de saberes populares, a la utilización de zooterápicos naturales y de plantas forrajeras nativas y exóticas, como también referidas al manejo del sistema de pastoreo sobre el monte natural, con el fin de disminuir la incidencia de la introducción de insumos como medicamentos y alimentos externos al sistema.Eje B1 Sistemas de producción de base agroecológica (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Universal Magnetic Properties of sp3^3-type Defects in Covalently Functionalized Graphene

Using density-functional calculations, we study the effect of sp$^3$-type defects created by different covalent functionalizations on the electronic and magnetic properties of graphene. We find that the induced magnetic properties are {\it universal}, in the sense that they are largely independent on the particular adsorbates considered. When a weakly-polar single covalent bond is established with the layer, a local spin-moment of 1.0 $\mu_B$ always appears in graphene. This effect is similar to that of H adsorption, which saturates one $p_z$ orbital in the carbon layer. The magnetic couplings between the adsorbates show a strong dependence on the graphene sublattice of chemisorption. Molecules adsorbed at the same sublattice couple ferromagnetically, with an exchange interaction that decays very slowly with distance, while no magnetism is found for adsorbates at opposite sublattices. Similar magnetic properties are obtained if several $p_z$ orbitals are saturated simultaneously by the adsorption of a large molecule. These results might open new routes to engineer the magnetic properties of graphene derivatives by chemical means

Population parameters and nymphaea instars description of protortonia ecuadorensis (Hemiptera : Monophlebidae).

En Hemiptera, el infraorden Coccomorpha es considerado un taxón con gran potencial invasivo. En este contexto, se han observado infestaciones de Protortonia ecuadorensis (Hemiptera: Monophlebidae) sobre hospedantes arbóreos neotropicales de alto valor económico y ambiental en el área urbana de Tunja (Boyacá, Colombia). Objetivo. En el presente trabajo se analizaron algunos aspectos biológicos de esta especie, registrando atributos de su ciclo de vida, factores de mortalidad-fecundidad y descripción de sus instares ninfales en la zona de estudio. Metodología. El trabajo se realizó en condiciones de casa malla y laboratorio. Por una parte, ninfas de P. ecuadorensis provenientes de campo se establecieron y observaron sobre esquejes de S. humboldtiana en una estructura de madera, plástico y polisombra de 3,8 m3 bajo casa malla. Por otro lado, 120 huevos obtenidos se acondicionaron en laboratorio en recipientes de polipropileno, provistos con algodón, realizando observaciones y toma semanal de datos hasta la obtención de adultos. Resultados. A partir de las ninfas colectadas en campo, se registró un ciclo de vida univoltino de 301,8 ± 40,5 días (14,5°C; H.R: 72,5%; Fotoperiodo 12 horas), pasando por tres instares ninfales de 283,6 ± 32,4 días y longevidad estimada en 18,2 ± 8,1 días. El índice de mortalidad específico (qx ) calculado en la tabla de vida, se estimó para huevo en 0,24; ninfa I 0,17; ninfa II 0,47 y ninfa III 0,83. La tasa intrínseca de crecimiento per cápita (r= -0,63<0), al igual que el índice reproductivo neto Ro (0,798><1) indican una posible diapausa bajo condiciones de casa malla. Conclusión. De acuerdo con las curvas de supervivencia l x halladas en ninfa III (0,19) y hembra adulta (0,03), se recomienda aplicar agentes de control en estas etapas de mayor susceptibilidad.><0), al igual que el índice reproductivo neto Ro (0,798<1) > <1) indican una posible diapausa bajo condiciones de casa malla. Conclusión. De acuerdo con las curvas de supervivencia l x halladas en ninfa III (0,19) y hembra adulta (0,03), se recomienda aplicar agentes de control en estas etapas de mayor susceptibilidad.  In Hemiptera, Cocomorpha infraorder is considered a taxon with a high invasive potential. Regarding with this, the Protortonia ecuadorensis scale has been observed infesting neotropical arboreal hosts of high economic and environmental value at the urban area of Tunja (Boyacá, Colombia). Objective. In this work some biological features of this scale specie were analized and observed, recording specific life cycle attributes, such as population dynamics, mortality-fecundity factors and a description of their nymphal instars in the studied place. Methodology. The work was conducted under a mesh house and laboratory conditions. In one hand, nymphs from the field were stablished on S. humboldtiana cuttings located in a 3,8 m3 wood, plastic and mesh structure into a mesh house. On the other hand, 120 eggs were conditioned in polipropilene dishes with wood. Weekly observations and data collection were done util adult emergence. Results. From the nymphs collected in the field, a 301,8 ± 40,5 days univoltine life cycle was registered (14.5°C, RH: 72.5; 12 hours photoperiod), with three nymphal stages of 283,6 ± 32,4 days and 18,2 ± 8,1 days estimated longevity. The specific mortality rate (qx ) calculated in the life table by cohorts, was estimated for egg in 0.24; nymph I 0, 17, nymph II 0,47 and nymph III 0,83. The intrinsic per capite growth rate (r= -0, 63<0), as well as the net reproductive index Ro (0,798><1) indicate a possible diapause under hoop house. Conclusion. According to the survival curves (lx) found in nymph III (0,19) and adult female (0,03), the application of control agents in these susceptible stages is recommended.> <0), as well as the net reproductive index Ro (0,798 <1) indicate a possible diapause under hoop house. Conclusion. According to the survival curves (lx) found in nymph III (0,19) and adult female (0,03), the application of control agents in these susceptible stages is recommended

Gene discovery in Triatoma infestans

Background: Triatoma infestans is the most relevant vector of Chagas disease in the southern cone of South America. Since its genome has not yet been studied, sequencing of Expressed Sequence Tags ( ESTs) is one of the most powerful tools for efficiently identifying large numbers of expressed genes in this insect vector. Results: In this work, we generated 826 ESTs, resulting in an increase of 47% in the number of ESTs available for T. infestans. These ESTs were assembled in 471 unique sequences, 151 of which represent 136 new genes for the Reduviidae family. Conclusions: Among the putative new genes for the Reduviidae family, we identified and described an interesting subset of genes involved in development and reproduction, which constitute potential targets for insecticide development

Stiff monatomic gold wires with a spinning zigzag geometry

Using first principles density functional calculations, gold monatomic wires are found to exhibit a zigzag shape which remains under tension, becoming linear just before breaking. At room temperature they are found to spin, what explains the extremely long apparent interatomic distances shown by electron microscopy.The zigzag structure is stable if the tension is relieved, the wire holding its chainlike shape even as a free-standing cluster. This unexpected metallic-wire stiffness stems from the transverse quantization in the wire, as shown in a simple free electron model.Comment: 4 pages, latex, 5 figures, submitted to PR

Pretratamiento con hialuronidasa mejora la tinción de colágeno en notocorda de esturión

Objective: The current study aimed to design a histological method to determine the presence and organization of the collagen network in sturgeon notochord. Methods: Serial sections of sturgeon notochord (Acipenser naccarii) were used and assigned to two different experimental groups: Hyaluronidase pre-treatment (HP) in an alcohol acid solution (1% HCl in 70% alcohol solution) for 15 min and hyaluronidase solution in a 2 µg/ ml concentration (pre-heated at 37º C), and control (CTR) group, without pre-treatment. Then, the ECM was assessed by two histochemical methods: Picrosirius Red (PR) staining for 30 min with Sirius red (0.1% of Sirius red in saturated aqueous picric acid), for collagen bundle staining, and Alcian Blue (AB) staining for glycosaminoglycans detection. Results: Samples analyzed in this study showed positive histochemical reaction for collagen fibers in both experimental groups. Referring to PR staining, the CTR group presented a larger and homogeneous reaction was observed in the entire samples, whereas HP group presented a more definite and intense pattern of collagen network. Also, this more intense signal in HP group matched with an increase of birefringence in polarized microscopy images of PR. However, HP group showed a lower intense and more heterogeneous signal when was compared with CTR group in AB staining. Conclusion: Using a simple histological example, our study illustrates the capability of a hyaluronidase pre-treatment to enhance picrosirius red staining in sturgeon notochord trough light and polarized microscopy.Objetivo: El presente estudio tiene por objetivo diseñar un método histológico para determinar la presencia y organización de la red de colágeno en la notocorda del esturión. Métodos: Secciones seriada de la notocorda de esturión (Acipenser naccarii) fueron utilizadas y se asignaron a dos grupos experimentales diferentes: pretratamiento de hialuronidasa (HP) en una solución de alcohol ácido (HCl al 1% en solución de alcohol al 70%) durante 15 minutos y posteriormente a una solución de hialuronidasa en una concentración de 2 μg / ml (precalentada a 37º C) y grupo de control (CTR), sin tratamiento previo. Luego, la ECM se evaluó mediante dos métodos histoquímicos: tinción Picrosirius Red (PR) durante 30 minutos con rojo Sirio (0,1% de rojo Sirio en una solución saturada de ácido pícrico), para la tinción de colágeno; y tinción con Alcian Blue (AB) para detección de glicosaminoglicanos. Resultados: Las muestras analizadas en este estudio mostraron una reacción histoquímica positiva para las fibras de colágeno en ambos grupos experimentales. Con respecto a la tinción PR, el grupo CTR presentó una reacción mayor y más homogénea en toda la superficie de las muestras, mientras que el grupo HP presentó un patrón red de colágeno más definido e intenso. Además, esta señal más intensa en el grupo HP coincidió con un aumento de la birrefringencia en las imágenes de microscopía polarizada de PR. Sin embargo, el grupo HP mostró una señal menos intensa y más heterogénea cuando se comparó con el grupo CTR en la tinción AB. Conclusión: Utilizando un ejemplo histológico simple, nuestro estudio ilustra la capacidad de un pretratamiento de hialuronidasa para mejorar la tinción de picrosirius en la notocorda del esturión a través de la luz y la microscopía polarizada

Use of sonic tomography to detect and quantify wood decay in living trees.

Premise of the studyField methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes.Methods and resultsLiving trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness.ConclusionsSonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees

Origin of anomalously long interatomic distances in suspended gold chains

The discovery of long bonds in gold atom chains has represented a challenge for physical interpretation. In fact, interatomic distances frequently attain 3.0-3.6 A values and, distances as large as 5.0 A may be seldom observed. Here, we studied gold chains by transmission electron microscopy and performed theoretical calculations using cluster ab initio density functional formalism. We show that the insertion of two carbon atoms is required to account for the longest bonds, while distances above 3 A may be due to a mixture of clean and one C atom contaminated bonds.Comment: 4 pages, 4 Postscript figures, to be published in Physical Review Letter

ILC3s restrict the dissemination of intestinal bacteria to safeguard liver regeneration after surgery.

It is generally believed that environmental or cutaneous bacteria are the main origin of surgical infections. Therefore, measures to prevent postoperative infections focus on optimizing hygiene and improving asepsis and antisepsis. In a large cohort of patients with infections following major surgery, we identified that the causative bacteria are mainly of intestinal origin. Postoperative infections of intestinal origin were also found in mice undergoing partial hepatectomy. CCR6+ group 3 innate lymphoid cells (ILC3s) limited systemic bacterial spread. Such bulwark function against host invasion required the production of interleukin-22 (IL-22), which controlled the expression of antimicrobial peptides in hepatocytes, thereby limiting bacterial spread. Using genetic loss-of-function experiments and punctual depletion of ILCs, we demonstrate that the failure to restrict intestinal commensals by ILC3s results in impaired liver regeneration. Our data emphasize the importance of endogenous intestinal bacteria as a source for postoperative infection and indicate ILC3s as potential new targets