Enhancing the Production and Sustainability of Pasture-Fed Beef Using Non-Traditional Legume Forages

Despite the increasing worldwide demand for beef as a protein source, consumers are concerned about the sustainability of ruminant production systems. Their main concerns are animal welfare for feedlot-fed animals, greenhouse gas (GHG) emissions, global warming and worker safety. Traditional feedlot-based beef production systems have been associated with locally greater levels of soil, water and air contamination, as well as the overuse of antibiotics and growth hormones. The use of legume pastures such as cicer milkvetch (CMV) and birdsfoot trefoil (BFT), which fix their own nitrogen (N) and often contain beneficial secondary compounds such as tannins and provide for rapid gain and improved meat quality, holds promise as an alternative strategy to feedlots for beef finishing. These legumes can mitigate GHG emissions without reducing beef productivity and improve enterprise profitability when sold locally as natural or organic pasture-finished meat. Tannins can be beneficial to ruminants or some types, especially in high concentrations, can have anti-herbivore properties. The condensed tannins synthesized by BFT are known to prevent bloat and to enhance the production of ruminants. More generally, tannins are beneficial not only to the plants that accumulate them, but can also slow soil mineralization of organic matter, better matching N release to plant uptake. Ruminants can convert fibrous feedstuffs not suitable for human consumption, such as corn stalks, into sources of high-quality protein for human consumption, and thrive without grain on pastures and hay produced on marginal land that is not suitable for cultivation. Legumes pay a key role in the mitigation of environmental impacts of beef production, because their elevated forage quality increases digestion rate, intake and animal gain, their tannins improve the efficiency of rumen N utilization, and their quality and tannin concentrations both tend to reduce enteric CH4 emissions and N losses. Likewise, plant litter and manure from tannin-containing species would help to sequester N and carbon in the production system, helping to achieve sustainable beef production. Evaluation of the sustainability of ruminant production systems should be based on their environmental impact, the nutritive value of the food produced, the appropriate use of agricultural land, and the economic sustainability of producers and their rural communities

Enhancing the Production and Sustainability of Pasture-Fed Beef Using Non-Traditional Legume Forages

Tesis para obtener el grado de Doctor of Philosophy (PhD), de la Utah State University, en agosto de 2020Despite the increasing worldwide demand for beef as a protein source, consumers are concerned about the sustainability of ruminant production systems. Their main concerns are animal welfare for feedlot-fed animals, greenhouse gas (GHG) emissions, global warming and worker safety. Traditional feedlot-based beef production systems have been associated with locally greater levels of soil, water and air contamination, as well as the overuse of antibiotics and growth hormones. The use of legume pastures such as cicer milkvetch (CMV) and birdsfoot trefoil (BFT), which fix their own nitrogen (N) and often contain beneficial secondary compounds such as tannins and provide for rapid gain and improved meat quality, holds promise as an alternative strategy to feedlots for beef finishing. These legumes can mitigate GHG emissions without reducing beef productivity and improve enterprise profitability when sold locally as natural or organic pasture-finished meat. Tannins can be beneficial to ruminants or some types, especially in high concentrations, can have anti-herbivore properties. The condensed tannins synthesized by BFT are known to prevent bloat and to enhance the production of ruminants. More generally, tannins are beneficial not only to the plants that accumulate them, but can also slow soil mineralization of organic matter, better matching N release to plant uptake. Ruminants can convert fibrous feedstuffs not suitable for human consumption, such as corn stalks, into sources of high-quality protein for human consumption, and thrive without grain on pastures and hay produced on marginal land that is not suitable for cultivation. Legumes pay a key role in the mitigation of environmental impacts of beef production, because their elevated forage quality increases digestion rate, intake and animal gain, their tannins improve the efficiency of rumen N utilization, and their quality and tannin concentrations both tend to reduce enteric CH4 emissions and N losses. Likewise, plant litter and manure from tannin-containing species would help to sequester N and carbon in the production system, helping to achieve sustainable beef production. Evaluation of the sustainability of ruminant production systems should be based on their environmental impact, the nutritive value of the food produced, the appropriate use of agricultural land, and the economic sustainability of producers and their rural communities.EEA BordenaveFil: Bolletta, Andrea Ivana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina

Perennial grasses of different successional stages under various soil water inputs: do they differ in root length density?

Information about root length density (RLD) on perennial grasses of different successional stages exposed to various soil water inputs is limited. The effects on RLD of different soil water inputs were evaluated in the late-seral Stipa clarazii Ball, the comparatively earlier-seral S. tenuis Phil, and the earlyseral S. gynerioides Phil. Field studies were conducted in 1996 and early 1997, although treatments were imposed since 1995. S. clarazii and S. tenuis are two important palatable perennial tussock grasses in temperate, semiarid rangelands of central Argentina, where S. gynerioides is one of the most abundant, unpalatable perennial grass species. It was hypothesized that 1) S. clarazii and S. tenuis have a lower RLD under irrigated than under rainfed or water stress conditions, 2) S. clarazii has a greater RLD than S. gynerioides and S. tenuis under all water inputs and sampling dates, and 3) the RLD of the three species will vary with sampling date, within each species and soil water level. Results led to reject hypothesis 1 and accept hypotheses 2 and 3. Maintenance of root growth under all water inputs would allow these species a greater soil exploration and resource finding to sustain regrowth in their native, semiarid environments. Also, the study demonstrated that late-seral perennial grasses (S. clarazii) should have a superior competitive ability than earlier seral grasses (S. tenuis and S. gynerioides) because of, at least in part, their greater average RLD under water stress, rainfed and irrigated conditions.La información sobre densidad de longitud de raíces (DLR) es escasa en gramíneas perennes de diferentes estados sucesionales expuestas a varios niveles hídricos del suelo. Los efectos de distintos niveles hídricos sobre la DLR fueron evaluados en gramíneas perennes de etapas sucesionales tardías (Stipa clarazii Ball.), intermedias (S. tenuis Phil.), y tempranas (S. gynerioides Phil.). Se condujeron estudios de campo en 1996 y principios de 1997, aunque los tratamientos fueron impuestos desde 1995. S. clarazii y S. tenuis son importantes gramíneas perennes cespitosas palatables en pastizales templados semiáridos del centro de Argentina, donde S. gynerioides es una de las especies de gramíneas perennes no palatables más abundantes. Se probaron las siguientes hipótesis: 1) S. clarazii y S. tenuis tienen menor DLR bajo condiciones de riego que bajo condiciones naturales o estrés hídrico, 2) S. clarazii tiene mayor DLR que S. gynerioides y S. tenuis bajo todos los niveles hídricos y fechas de muestreo, y 3) la DLR de las tres especies varía con la fecha de muestreo, dentro de cada especie y nivel hídrico del suelo. Los resultados condujeron a rechazar la hipótesis 1 y aceptar las hipótesis 2 y 3. El mantenimiento del crecimiento radical en todos los niveles hídricos les permitiría a estas especies una mayor exploración del volumen del suelo y adquisición de recursos que mantengan el rebrote en sus ambientes nativos, semiáridos. El estudio también demostró que las gramíneas perennes de estados sucesionales tardíos (S. clarazii) deberían tener mayor capacidad competitiva que especies más tempranas en la sucesión vegetal (S. tenuis y S. gynerioides) debido, al menos en parte, a su mayor DLR promedio bajo condiciones de estrés hídrico, naturales y de riego.EEA BordenaveFil: Busso, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Busso, Carlos Alberto. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina.Fil: Busso, Carlos Alberto. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Bolletta, Andrea Ivana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina

Del tiempo, la Educación y el Aprendizaje

En el marco del Programa de Intercambio de Movilidad Docente a Madrid de la SPU, Viviana Bolletta, entrevistó en el Departamento de Teoría e Historia de la Educación de la Facultad de Educación de la Universidad Complutense de Madrid, al Dr. en Filosofía y Ciencias de la Educación, Fernando Bárcena, catedrático de Filosofía de la Educación en la mencionada universidad. Es autor de libros y ensayos focalizados en aspectos filosóficos y educativos entre los que se destacan HannahArendt, una filosofía de la natalidad (2006), El delirio de las palabras

El lugar de la investigación en tiempos de pandemia. Reflexividad y perplejidad

Frente a lo intempestivo de la pandemia y su consecuente situación de aislamiento social preventivo y obligatorio -ASPO-, se torna relevante repensar el lugar de la investigación en tiempos de pandemia y la responsabilidad -como investigadores- de captar los sentidos y los significados construidos socioeducativamente en este tiempo de excepcionalidad. En este sentido, considero relevante compartir con ustedes nuestra experiencia de trabajo, la cocina de la investigación: nuestras reflexiones, nuestras decisiones y nuestras apuestas, que derivaron en la necesidad de reforzar las preguntas de investigación en torno a las condiciones para la transmisión, pero en situación de virtualidad o acompañamiento en línea, a los estudiantes de escuelas secundarias de la ciudad de Viedma (Rio Negro). Tres ejes de análisis sostienen esta ponencia: Uno, la concepción de investigación, que nos remite a los supuestos ontológicos, epistemológicos y metodológicos que subyacen en la investigación y que nos devuelve preguntas tales como: ¿qué es investigar y para qué investigar?, ¿cómo investigar en situaciones excepcionales, inéditas?, ¿Qué lugar ocupamos los investigadores? Pero también: ¿Qué pasa con la transmisión en tiempos de virtualidad? Otro elemento es que la investigación, en tiempos de pandemia, de ASPO, de incertidumbre, nos remite a la idea de lo intempestivo, a tiempos de lazos educativos virtualizados: una pandemia que se nos fue instalando de a poco como certeza nos interpela en nuestras vidas cotidianas e inunda todos los lazos, no solo los educativos. Como dice Perla Zelmanovich (2020), en ese marco, las categorías de perplejidad y reflexividad que nos ofrece la etnografía como categoría teórica y como recurso metodológico del que disponemos los investigadores para reflexionar, para tomar conciencia de nuestros condicionamientos sociales, se torna clave para pensar la investigación. Y, por último, para compartir algunos hallazgos de las condiciones actuales para la transmisión en tiempos de virtualidad, investigación mediante, luego de asumir la necesidad de estar ahí, investigando.Palabras clave: investigación, reflexividad, perplejidad, transmisión

Social Influence in Networks

This thesis is composed by three standalone papers. The first chapter is about opinion formation processes. Individuals influence each other according to the network structure. If the network is connected and satisfies other mild assumptions, the society will reach a consensus. Therefore, it is a matter of interest understanding when the network would be connected or not. Here, we develop a model where the network takes place endogenously, and agents update their opinions accordingly. We study general conditions on the initial distribution of opinions such that consensus will be reached. We provide sufficient conditions for connectedness. In the dynamic model we show that polarization both in the transition and the long run. This essay is a joint work with Paolo Pin (Bocconi University). The second chapter is about peer effects. I consider how social pressure affects the strategic network formation process. Agents choose their links subject to mutual consent, and then equilibrium behaviors are determined by an underlying game where agents choose their effort. I provide a characterization result for all pairwise Nash stable network, and use farsightedness to avoid cycles. As an application, I consider peer effects in the classroom. Results suggest that we could set optimal policies to improve outcome of low achievement students through targeted incentives schemes. In the last chapter I focus on the interaction between real and virtual life. To do so I propose a model of search where agents choose in equilibrium how intense is their on-line activity. The outcomes of the game depend on the network, which takes place through a semi-random process. I extend the standard random network formation allowing agents to hold a certain degree of choice. The model allows to track characteristics on the meeting environment and individual preferences that would make virtual and real life substitutes or complements

Malignant glaucoma following gonioscopy-assisted transluminal trabeculotomy: a case report

Background: To report a case of malignant glaucoma that developed after gonioscopy-assisted transluminal trabeculotomy (GATT). Case presentation: An 85-year-old male pseudophakic patient afected by pseudoexfoliative glaucoma (PEXG), unresponsive to medical glaucoma treatment, underwent uneventful GATT surgery. On the frst day after surgery, the eye showed a shallow central and peripheral anterior chamber (AC) with a raised intraocular pressure (IOP) measured at 55mmHg. Optical coherence tomography and ultrasound biomicroscopy confrmed the diagnosis of malignant glaucoma. Laser iridotomy, posterior capsulotomy and hyaloidotomy were performed, and the patient was treated with atropine sulphate 1%, maximum topical and systemic ocular hypotensive drugs with no improvement in the IOP. Subsequently, the patient underwent pars plana anterior vitrectomy, resulting in deepening of the AC with opening of the iridocorneal angle and decrease of the IOP. No further postoperative complications were recorded, and the IOP remained controlled 12months after surgery without antiglaucoma medications. Conclusions: Despite the minimally invasive profle of GATT, malignant glaucoma may develop after this procedure. Early recognition and prompt treatment are mandatory for preventing permanent visual loss

Silicone gauzes with α-tocopherol acetate oil in skin graft donor site dressing

Split-thickness skin graft is one of the most used procedures in plastic surgery. This procedure involves numerous painful dressings at the donor site. α-Tocopherol acetate has anti-oxidative and anti-inflammatory properties and it can reduce the local bacterial growth, thereby promoting wound healing. We designed a prospective study to evaluate the effects of two different kinds of dressings at skin graft donor sites. A total of 30 patients were subjected to daily dressings with α-tocopherol acetate oil and traditional moist gauzes (group 1). Another 30 patients were subjected to dressings every 4 days with α-tocopherol acetate oil and silicone–vitamin E gauzes (group 2). Healing time, infection rate, patient's pain perception and costs were evaluated in both the groups. No statistically significant difference was found in terms of healing time. The infection rate was slightly different in the two groups. Significant reduction of pain perception was detected in group 2. In the same group, significant reduction in the total cost of the treatment was also observed. α-Tocopherol acetate oil and silicone–vitamin E gauzes may represent a safe, simple, painless and inexpensive method for improving skin graft donor site healing