Effects of field inoculation with VAM and bacteria consortia on root growth and nutrients uptake in common wheat

This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fungus Rhizophagus irregularis and the diazotrophic N-fixing bacterium Azotobacter vinelandii on root and shoot growth, yield, and nutrient uptake in common wheat (Triticum aestivum L.) in order to improve the sustainable cultivation of this widespread crop. The trials were carried out in controlled conditions (rhizoboxes) and in open fields over two years to investigate the interaction between inoculation and three doses of nitrogen fertilization (160, 120 and 80 kg ha1) in a silty-loam soil of the Po Plain (NE Italy). In rhizoboxes, efficient root colonization by R. irregularis was observed at 50 days after sowing with seed inoculation, together with improved root tip density and branching (+~30% vs. controls), while the effects of post-emergence inoculation by soil and foliar spraying were not observable at plant sampling. In the open, field spraying at end tillering significantly increased the volumetric root length density (RLD, +22% vs. controls) and root area density (+18%) after about two months (flowering stage) in both years under medium and high N fertilization doses, but not at the lowest N dose. In absence of inoculation, RLD progressively decreased with increased N doses. Inoculation had a negligible effect on grain yield and N uptake, which followed a typical N dose-response model, while straw Zn, P, and K concentrations were seldom improved. It is concluded that medium-high N fertilization doses are required to achieve the target yield and standards of quality (protein contents) in wheat cultivation, while the use of this mixed VAM-PGPR biofertilizer appears to be a sustainable mean for minimizing the adverse effects of chemical N fertilizers on root expansion and for improving the uptake of low-mobility nutrients, which has potentially relevant environmental benefits

Exchange rate prediction using changes in commodity prices

This dissertation aims to analyze the effect of commodity price changes on exchange rates, and to test whether they are any good in predicting the exchange rate of several currencies against the US dollar. I compare the forecast performance of models that use commodity prices with that of a random walk model, and analyze which performs better, I also analyze an economic fundamentals model. This analysis is done both in-sample and out-of-sample. My results are positive, given that all models tested outperform the random walk model for the majority of the countries tested. It is also concluded that a model that uses only commodity prices is the best performer out-of-sample. A striking result is that, in this study, the economic fundamentals model outperforms the random walk, despite past research suggesting that there is no relationship between economic fundamentals and exchange rates.Esta tese tem como objetivo analisar efeito de variações no preço de commodities em taxas de câmbio, e testar se são uteis para prever taxas de câmbio de varias divisas contra o dolar americano. Eu comparo a performance de previsão de modelos que usam preços de commodities com um modelo de random walk, e analiso qual performa melhor, analiso também um modelo de fundamentais económicos. Esta análise é feita in-sample e out-of-sample. Os meus resultados são positivos, uma vez que todos os modelos performam melhor que o modelo de random walk para a maioria dos países testados. Também se conclui que um modelo que use apenas preços de commodities tem a melhor performance out-of-sample. Um resultado inesperado é que, nesta tese, o modelo de fundamentais económicos performa melhor que o modelo de random walk, embora pesquisa anterior sugira que não existe nenhuma relação entre fundamentais económicos e taxas de câmbio

El peronismo y las elecciones bonaerenses. De la derrota a la consolidación en el gobierno provincial, 1983-1991

Este artículo analiza las performances electorales del peronismo bonaerense entre 1983 y 1991. Intenta comprender las causas que incidieron en que, tras ser derrotado en las primeras elecciones, recuperara la primacía en 1987 y se consolidara como partido en el gobierno. Indaga acerca de la evolución del voto justicialista en la provincia en elecciones de gobernador (1983, 1987 y 1991) y parlamentarias (1985 y 1989), aplicando inferencia ecológica. Describe tendencias referidas a la evolución del padrón y la participación electoral, la distribución seccional y la expansión territorial del voto peronista. Además, relaciona las conclusiones obtenidas del análisis cuantitativo con los procesos históricos. Brinda algunos indicios que complejizan las explicaciones en torno a los fenómenos político-electorales y contribuye a entender en su especificidad la historia política bonaerense del período reciente.This article analyzes the electoral performances of Buenos Aires province's Peronism between 1983 and 1991. Its intention is to understand why after the defeat of 1983, Peronism regained the primacy in 1987 and was consolidated as the ruling party. The evolution of Peronist vote in governor and parliamentary elections (1983, 1985, 1987, 1989, and 1991) is analyzed applying ecological inference. Trends about the electoral register and electoral participation are described, and are referred to the electoral geography of the Peronist vote. Besides, the conclusions achieved through the quantitative analyses are related to the historical processes. The article offers some hints that bring complex explanations about political and electoral events and helps to understand specifically the political history of Buenos Aires in recent times.Fil: Ferrari, Marcela Patricia. Universidad Nacional de Mar del Plata. Facultad de Humanidades; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Ricci, Lila. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Suárez, Fernando Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentin

Hybrid layers of etch-and-rinse versus self-etching adhesive systems

Objective: To evaluate the effectiveness in the formation of resin tags, adhesive lateral branches and hybrid layers of five adhesive systems, when bonding to dentine. Material and Methods: Flat dentin surfaces from 25 molars were bonded with several adhesive systems according to the manufacturers? instructions. Composite build-ups were constructed incrementally with Tetric Ceram. The Specimens were sectioned parallel to the long axis. One section was treated with phosphoric acid and sodium hypochlorite in order to reveal the hybrid layer formation. The other section was stored in 30% hydrochloric acid to detect resin tags and adhesive lateral branch formation. Results: The two etch-and-rinse self-priming adhesives exhibited thicker hybrid layers than those found in self-etching adhesive systems. The all-in-one adhesive showed droplet formation between the adhesive and the resin composite. The resin tags formed with the etch-and-rinse adhesives were much longer than those found with the self-etching adhesives. Lateral branch formation was observed in etch-and-rinse adhesives and in one of the self-etch adhesives Clearfil SE Bond (SEB). Conclusion: The formed hybrid layer obtained with the two-step selfetching adhesives and the etch-and-rinse systems were continuous and uniform in thickness. Droplets within the all-in-one adhesive layer may occur as a result of water absorption from dentin through osmosis, and may interfere with proper resin polymerization. Resin tags obtained with SEB and the etch-and-rinse adhesive systems showed lateral branches, which is a sign of proper resin infiltration

Approximate solutions of one dimensional systems with fractional derivative

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Desarrollo del razonamiento covariacional en estudiantes de nivel medio superior. El caso de la función exponencial

En el presente escrito se discuten las ideas sobre la covariación logarítmica-exponencial (la yuxtaposición de una progresión aritmética y otra geométrica) para realizar un acercamiento al concepto de función exponencial, presentada a través de una construcción de puntos en GeoGebra. Dicho trabajo se realizó con estudiantes del nivel medio superior de la Universidad Autónoma de Guerrero. Se utilizó la metodología basada en diseño para la recolección y análisis de datos. Los estudiantes logran identificar dos variaciones distintas, una para los valores de x y otra para los valores de y, no obstante, percibir la coexistencia y la codependencia no fue trivial

Morphological changes and expressions of AOX1A, CYP81D8, and Putative PFP genes in a large set of commercial maize hybrids under extreme waterlogging.

Waterlogging is a severe abiotic stressor causing significant growth impairment and yield losses in many crops. Maize is highly sensitive to the excess of water, and against the background of climate change there is an urgent need for deeper insights into the mechanisms of crop adaptation to waterlogging. In the present study, changes in maize morphology at the 4\u20135 leaf stage and the expression of three candidate genes for flooding tolerance in plants subjected to six continuous days of waterlogging were recorded in 19 commercial hybrids and in the inbred line B73, with the aim of investigating the current variability in cultivated hybrids and identifying useful morphological and molecular markers for screening tolerant genotypes. Here it was demonstrated that root parameters (length, area, biomass) were more impaired by waterlogging than shoot parameters (shoot height and biomass). Culm height generally increased in stressed plants (by up to C24% vs. controls), while shoot biomass was significantly reduced in only two hybrids. Root biomass was reduced in all the hybrids, by an average of 30%, and significantly in 7 hybrids, while root length and area were even more severely reduced, by 30\u201355% vs. controls, depending on the hybrid. The earlier appearance of aerial roots seemed to be associated with greater root injuries. In leaves, the transcript of the PFP enzyme (phosphofructokinase), which is involved in glycolytic reactions, was markedly up-regulated (up to double the values) in half the waterlogged hybrids, but down-regulated in the others. The transcript of CYP81D8 (ROS-related proteins) in waterlogged plants exhibited relevant increases or strong decreases in level, depending on the hybrid. The transcript of the AOX1A gene, coding for a mitochondrial respiratory electron transport chain-related protein, was markedly down-regulated in all the treated hybrids. Expression analysis of these genes under extreme waterlogging only partially correlate with the shoot and root growth impairments observed, and AOX1A seems to be the most informative of them

Surface treatments for improving bond strength to prefabricated fiber posts: A literature review

This literature review summarizes the research on fiber post surface treatments and provides information related to their benefit in enhancing bond strength to composites, based on the results of original scientific full papers from peer-reviewed journals listed in Pub Med. The search was conducted using the terms "fiber post," "surface treatment" "surface conditioning," "etching" and "sandblasting." A consistent number of in vitro studies that investigated the surface treatment of fiber posts in an attempt to improve bond strength have been published to date. Their results have been summarized in the following categories: chemical treatments and micromechanical treatments of fiber post surfaces (or a combination of both principles). The majority of available literature data is based on studies that investigated different "chairside" post superficial treatments. According to the in vitro results, surface conditioning improves fiber post bonding properties, and the bond strength of pre-treated fiber posts to restorative materials is satisfactory. Long-term clinical studies are needed prior to making a general recommendation for their use

Instante Crítico con Jitter: un estado poco probable

Este trabajo trata sobre la probabilidad de encontrar un instante crítico con los peores casos de jitter de instanciación en un Sistema de Tiempo Real. Se analizará mediante simulaciones, que esta condición de planificación acontece muy rara vez, más aún cuando los sistemas poseen numerosas tareas. Consecuentemente, basar el diseño del sistema en esta condición puede provocar implementaciones de hardware sobredimensionadas para el funcionamiento normal del mismo. Por otro lado, esta baja probabilidad introduce un gran pesimismo en los métodos de evaluación de planificabilidad.Fil: Paez, Francisco Ezequiel. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Urriza, José Manuel. Universidad Nacional de la Patagonia; ArgentinaFil: Ferrari, Mariano Andrés. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Cayssials, Ricardo Luis. Universidad Nacional del Sur; ArgentinaFil: Orozco, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin