Novel Grasses and Legumes Germplam: Advances and Perspectives for Tropical Zones

It has been the aim, in the present article, to bring together as much as possible scientific evidence and experience in new available germplasm for tropical zones. The economic importance of the Brachiaria, Paspalum and Pennisetum grasses is well established. New germplasm has become available since 1980. This paper reviews evaluations of Brachiaria accessions in humid lowlands and savannas of tropical America. The selection criteria need to be revised. Also, it is necessary to expose the new material as early as possible to farmers in order to select new germplasm with high chances of adoption. Within the genus Paspalum, P. dilatatum is possibly the most widespread. It has made a considerable contribution in the past, providing some of the best early season feed. In this paper, new data on P. atratum will be presented. Since 1985 a great effort had been made on Pennisetum. New cultivars are available. The main legumes genera to be discussed are Arachis spp., Calopogonium mucunoides, Centrosema spp., Desmodium spp., Glycine spp., Macroptilium spp., Neonotonia wightii and Stylosanthes spp. On Arachis, a historical perspective of the collection and evaluation in South America as well as a summary of the regional experience on Central America, Australia and United States would be presented. Some preliminary data on the drought tolerance and animal performance is discussed. For more than one hundred accessions evaluated through 1992 until 1997, twenty accessions of A. pintoi are outstanding and deserve further regional evaluation. Calopogonium mucunoides, although not widely used (like any other pasture legume today in tropical America), is the most popular forage legume amongst farmers in Brazil. A collection of 215 accessions was evaluated in the Cerrado ecosystem. A negative relationship between the degree of pilosity and in vitro dry matter digestibility was found. Within the seventeen accessions selected, two of them, CIAT 822 and 20709 were outstanding for their leaf retention during the dry season. Also, Macroptilium, Neonotonia and Stylosanthes, deserve special mention because attempts to develop cultivars from them have been determined and sustained. Finally, there is also an opportunity to search for new alternatives within the new available collection of N. wightii. Three new accessions are promising

Inclusion of [H3PW12O40] and [H4SiW12O40] into a silica gel matrix via "sol-gel" methodology

Indexación: Web of Science; Scopus.Here we report the inclusion of two Keggin Polyoxometalates (POMs), [H3PW12O40] and [H4SiW12O40], into silica gels by integrating them during the preparation of the SiO2 matrix via "sol-gel" methods. Aerogels were produced by supercritical drying of the wet gels impregnated with the POMs, and lyogels were obtained by means of a lyophilization process. These materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FT-IR) spectroscopy and thermoanalytical techniques (TGA-DSC). We found that a large fraction of POMs are lost during the aging time, and solvent exchange for lyophilization. However the thermal stability of the bare matrix is modified by the inclusion of POMs. Some aggregates with a high content of POMs were found via SEM-EDX.http://ref.scielo.org/3fg9t

Phytoplankton patchiness in two shallow waterbodies

The hydrodynamic behaviour in lentic ecosystems is closely related with the spatial and temporal evolution of their physical, chemical and biological characteristics. Because of this, and in order to improve our present knowledge on the limnological dynamics of such ecosystems, a coupled analysis on the relationship between the biological patterns and the governing hydrodynamics mechanisms it is necessary. This paper uses both field analysis and numerical simulation to describe the links between the water movements and the phytoplankton spatial distribution on two shallow waterbodies in the South of Spain: Alhama de Granada Reservoir (Granada) and Laguna Nueva de la Albufera de Adra (Almería). In both systems the observed phytoplankton spatial distribution exhibited dynamic patterns forced by hydrodynamical transport processes. The knowledge of this physical-biological coupling could be useful to outline the basic guidelines for water quality management.Los ecosistemas acuáticos leníticos se caracterizan por un intenso acoplamiento entre los mecanismos de transporte hidrodinámico que en ellos ocurren y la evolución espacial y temporal de sus principales variables físico-químicas y biológicas. En consecuencia y con el objetivo de mejorar nuestro entendimiento sobre la dinámica limnológica de este tipo de sistemas, resulta necesario el desarrollo de análisis interdisciplinares que profundicen en esta estrecha relación hidrodinámica-biología. En este trabajo se analiza, a partir de estudios de campo y simulaciones numéricas, el acoplamiento entre el movimiento de la masa fluida a nivel de macroescala y la distribución espacial del fitoplancton en dos ecosistemas acuáticos someros del Sur de España : el embalse de Alhama de Granada (Granada) y la Laguna Nueva de la Albufera de Adra (Almería). En ambos sistemas se han encontrado patrones dinámicos de distribución espacial de las microalgas, íntimamente relacionados con la dinámica de la masa de agua. El conocimiento de este acoplamiento resulta útil en la definición de líneas básicas para la adecuada gestión de la calidad del agua

Effect of addition of an ammonium source in UASB and EGSB reactors when treating low concentrated wastewater: granules morphology

In this work the effect on granules morphology by adding a supplementary nitrogen-ammonium source to UASB and EGSB reactors, treating a low concentrated wastewater is studied. Previously, a complex-synthetic-medium-concentratedwastewater (C/N ratio, 100:4) was fed for granule development and maturation, achieving similar removal performances (higher than 95 % in terms of COD) in both reactors. A subsequent period of 88 days treating low concentrated wastewater (C/N ratio, 100:0.5) led to the destabilisation of granules properties and operational performance in general in both reactors (COD removal efficiencies of approximately 50 %). Ammonium was subsequently supplemented to the low concentrated wastewater, in order to balance the nutrient content (C/N ratio, 100:10) and to study its effect on destabilised granules. After 28 days operating under these conditions, COD removal efficiencies recovered values of 82 and 90 % in UASB and EGSB, respectively. It was also observed, an improvement in granule appearance as given by microscopic observation.CONICYT (Chile); GRICES (Portugal)

The Nutritional Dynamic is Key for Use Optimal Forage and Increase of Meat Production

The nutritional content grass could be considered a key tool to determine the optimal forage use, based on the requirements of the cattle to maximize production and achieve a highly productive and profitable livestock. The degradation protein complex associated with autophagy plant determines to a great extent the protein content of the grass over time, being priority found the value nutritional required for the livestock for intensification the animal production. The crude protein requirements (CP, 13.5%) to cover nutritional needs in cattle, was established between 28±1 y 30±1 for the dry period and wet period respectively in Camello® hybrid grass. The weight gains to level protein above mentioned were substantially high in both periods. In dry period was 0.9 kg d-1 animal-1 and wet period 1.1 kg d-1 animal-1. The little difference in weight gain between periods clarifies our hypothesis

Diseño e implementación de un software educativo en Cálculo Numérico

En este trabajo presentamos las características de un software educativo que hemos desarrollado con MATLAB. Hemos diseñado este software para implementar los diferentes métodos de resolución de ecuaciones no lineales que se estudian en Cálculo Numérico. Esta materia corresponde al Profesorado en Matemática, Licenciatura en Física e Ingeniería Civil, carreras que se siguen en la Facultad de Ciencias Exactas y Naturales de la Universidad Nacional de La Pampa. Además, detallamos las motivaciones que nos llevaron a su diseño e implementación, como así también las modificaciones que se introdujeron tanto en las clases prácticas como teóricas. Estas modificaciones se fueron produciendo a partir del uso de este software y del análisis a-posteriori de la información obtenida por medio de encuestas a alumnos, y de la observación de clases. Finalmente, luego de utilizar este software durante tres años (versiones anteriores) y a partir de los resultados alcanzados, realizamos un análisis sobre las mejoras / correcciones necesarias para elaborar una versión final del mismo.Facultad de Informátic

Nasal immunization with the c-terminal domain of bcla3 induced specific igg production and attenuated disease symptoms in mice infected with clostridioides difficile spores

Clostridioides difficile is a Gram-positive, spore-forming bacterium that causes a severe intestinal infection. Spores of this pathogen enter in the human body through the oral route, interact with intestinal epithelial cells and persist in the gut. Once germinated, the vegetative cells colonize the intestine and produce toxins that enhance an immune response that perpetuate the disease. Therefore, spores are major players of the infection and ideal targets for new therapies. In this context, spore surface proteins of C. difficile, are potential antigens for the development of vaccines targeting C. difficile spores. Here, we report that the C-terminal domain of the spore surface protein BclA3, BclA3CTD, was identified as an antigenic epitope, over-produced in Escherichia coli and tested as an immunogen in mice. To increase antigen stability and efficiency, BclA3CTD was also exposed on the surface of B. subtilis spores, a mucosal vaccine delivery system. In the experimental conditions used in this study, free BclA3CTD induced antibody production in mice and attenuated some C. difficile infection symptoms after a challenge with the pathogen, while the spore-displayed antigen resulted less effective. Although dose regimen and immunization routes need to be optimized, our results suggest BclA3CTD as a potentially effective antigen to develop a new vaccination strategy targeting C. difficile spores

Arthropods of the Limarí River basin (Coquimbo Region, Chile): taxonomic composition in agricultural ecosystems

The Limarí valley, located in the Coquimbo Region of Chile, is an important agricultural area that is immersed in the transverse valleys of the Norte Chico. In recent decades, the continuous expansion of agriculture towards dry land zones has favored the migration and establishment of potential pests, such as arthropods, that may affect crops or be zoonotic agents. Based on the limited knowledge we have about the arthropod group present in the Limarí basin, our objective is to describe the taxonomic composition of the assemblage of economically important arthropods inhabiting this basin of the semiarid region of Chile. After reviewing historical data, specimen collections, and the specialized literature, a total of 414 arthropod species were recorded. Of the total number of species recorded, 92.5% were insects, the most diverse taxon, with 11 orders. Arachnids, in turn, were represented only by Acari with 31 species. The most widely represented orders of insects were Coleoptera, Hemiptera, and Lepidoptera. Within Coleoptera the most species-rich families were, in decreasing order of importance, Curculionidae, Coccinellidae, Cerambycidae, Scarabaeidae, Chrysomelidae (Bruchinae), Ptinidae, and Bostrichidae; within Hemiptera these were Aphididae, Diaspididae, Coccidae, Pseudococcidae, Pentatomidae and Rhopalidae; and within Lepidoptera they were Noctuidae and Tortricidae. We hope this study serves as a starting point for identifying the most diverse arthropod groups and developing pest monitoring and control programs. Highlights: A large percentage of phytophagous species, mainly belonging to Acari, Lepidoptera, Hemiptera and Coleoptera, were registered in the Limarí basin. Some families of agricultural importance (Aleyrodidae, Aphididae, Coccidae, Diaspididae, Margarodidae, Pseudococcidae), were observed in large agricultural crops in the basin (e.g., vines, oranges, mandarins, lemon trees, avocado trees, walnuts, olive trees, vegetable crops). A smaller fraction corresponded to the group of predators and parasitoids, mainly represented by Coleoptera (Coccinellidae), Neuroptera (Chrysopidae) and Hymenoptera (Braconidae, Encyrtidae, Ichneumonidae, Platygastridae, Signiphoridae). The richness and spatial records of arthropods were mostly concentrated between the city of Ovalle and the estuary of Punitaqui - the areas with most intense agricultural activity in the Limarí basin.The Limarí valley, located in the Coquimbo Region of Chile, is an important agricultural area that is immersed in the transverse valleys of the Norte Chico. In recent decades, the continuous expansion of agriculture towards dry land zones has favored the migration and establishment of potential pests, such as arthropods, that may affect crops or be zoonotic agents. Based on the limited knowledge we have about the arthropod group present in the Limarí basin, our objective is to describe the taxonomic composition of the assemblage of economically important arthropods inhabiting this basin of the semiarid region of Chile. After reviewing historical data, specimen collections, and the specialized literature, a total of 414 arthropod species were recorded. Of the total number of species recorded, 92.5% were insects, the most diverse taxon, with 11 orders. Arachnids, in turn, were represented only by Acari with 31 species. The most widely represented orders of insects were Coleoptera, Hemiptera, and Lepidoptera. Within Coleoptera the most species-rich families were, in decreasing order of importance, Curculionidae, Coccinellidae, Cerambycidae, Scarabaeidae, Chrysomelidae (Bruchinae), Ptinidae, and Bostrichidae; within Hemiptera these were Aphididae, Diaspididae, Coccidae, Pseudococcidae, Pentatomidae and Rhopalidae; and within Lepidoptera they were Noctuidae and Tortricidae. We hope this study serves as a starting point for identifying the most diverse arthropod groups and developing pest monitoring and control programs. Highlights: A large percentage of phytophagous species, mainly belonging to Acari, Lepidoptera, Hemiptera and Coleoptera, were registered in the Limarí basin. Some families of agricultural importance (Aleyrodidae, Aphididae, Coccidae, Diaspididae, Margarodidae, Pseudococcidae), were observed in large agricultural crops in the basin (e.g., vines, oranges, mandarins, lemon trees, avocado trees, walnuts, olive trees, vegetable crops). A smaller fraction corresponded to the group of predators and parasitoids, mainly represented by Coleoptera (Coccinellidae), Neuroptera (Chrysopidae) and Hymenoptera (Braconidae, Encyrtidae, Ichneumonidae, Platygastridae, Signiphoridae). The richness and spatial records of arthropods were mostly concentrated between the city of Ovalle and the estuary of Punitaqui - the areas with most intense agricultural activity in the Limarí basin

Impact of the \u3cem\u3eBrachiaria\u3c/em\u3e Hybrids on Both Soil Health and Carbon Stock on Livestock Production

Pastures occupy 30% of Earth and 80% of the entire agricultural area of the planet. To ensure food to the world and contribute to the quality of the environment, pasture-based animal production systems will also have to undergo through a more intense evolution. The intensification of tropical grasslands is an important strategy of land utilization in developing countries, contributing to increase production and minimize environmental impact through the best management practices. In this sense, the use of Brachiaria hybrids represents an excellent option, since combining the best traits of different Brachiaria species, with higher nutritive value, forage, and seed yield. Here we have evaluated six Brachiaria hybrids’ effects on both soil health and carbon stock. We observed that in all Brachiaria genotypes the mean carbon stock varied significantly in at least two soil depth categories. In general, carbon stock tends to get smaller as soil depth increases. Enzyme activity analysis showed there were no significant differences in the mean enzyme activity except in hybrid GP 3660 for β-glucosidase enzyme. Therefore, the adoption of Brachiaria hybrids might also help farmers to produce in an environmentally friendly manner, due to the potential benefits of Brachiaria to soil life enzyme activity and carbon mitigation