Use of urease inhibitors to reduce ammonia volatilization in Amazonian soils.

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Volatilização de amônia de ureias com ou sem inibidores de urease, submetidas a diferentes lâminas de irrigação.

O objetivo neste trabalho foi avaliar a volatilização de amônia de ureias com ou sem inibidores de urease, submetidas a diferentes lâminas de irrigação

Compostos orgânicos como alternativa para redução da perda de nitrogênio por volatilização.

A ureia é o fertilizante nitrogenado mais utilizado no Brasil e no mundo. Entretanto, a eficiência da ureia é reduzida devido às perdas de nitrogênio causadas pela volatilização de amônia (NH3) resultante da ação da urease, uma enzima extracelular produzida por microrganismos presentes no solo. Atualmente existem algumas alternativas para minimizar as perdas de nitrogênio da ureia e melhorar sua absorção pelas culturas. Dentre estas, destacam-se os inibidores de urease, sendo o mais conhecido o tiofosfato de N-(n-butil)triamida (NBPT). Outras substâncias têm sido investigadas com relação ao potencial de inibição da enzima urease, porém, poucas têm obtido resultados promissores. Neste contexto, o estudo objetivou avaliar o efeito de compostos orgânicos na redução da volatilização de amônia, em condições edafoclimáticas da Amazônia Sul Ocidental.

Ammonia loss from protected urea in soil under different irrigation depths.

This study presents an evaluation of the viability of using protected urea under different irrigation depths to reduce nitrogen losses caused by the volatilization of ammonia (NH3) under the conditions of the Southwestern Amazon. The study was carried out at the Experimental Station of Embrapa Rondônia, in the municipality of Porto Velho, Rondônia State, Brazil. The experiment was conducted in a Red-Yellow Latosol and arranged in a 5 x 6 factorial design consisting of a combination of five treatments (N sources) with six irrigation depths. The sources of N were as follows: 1) urea (45.5% N); 2) urea (44.3% N) + 0.15% copper and 0.4% boron; 3) urea (45% N) + NBPT; 4) urea (43% N) + sulfur (1%); and 5) control (without N). The irrigation depths were 0, 5, 10, 15, 20, and 25 mm. The results showed that, regardless of the use of urease inhibitors, an irrigation depth of 10 mm is suitable for incorporating urea into the soil and stabilizing N losses from NH3 volatilization. NBPT is the most efficient inhibitor under nonirrigated conditions. All N sources promote increases in the concentrations of nitric and ammonia nitrogen in the soil. In the first 15 days after fertilizer application, the highest concentrations of ammonium were in the 0 - 10 cm and 10 - 20 cm soil layers, and NBPT showed the highest ammonium content compared to that of the other sources in the 0 - 10 cm layer. The nitric nitrogen content in the soil was slightly influenced by the irrigation depth in the first 15 days after fertilizer application. However, the ammonia nitrogen content decreased exponentially with the increase in irrigation depth due to the movement of ammonia in the soil

The higher-level phylogeny of Archosauria (Tetrapoda:Diapsida)

Crown group Archosauria, which includes birds, dinosaurs, crocodylomorphs, and several extinct Mesozoic groups, is a primary division of the vertebrate tree of life. However, the higher-level phylogenetic relationships within Archosauria are poorly resolved and controversial, despite years of study. The phylogeny of crocodile-line archosaurs (Crurotarsi) is particularly contentious, and has been plagued by problematic taxon and character sampling. Recent discoveries and renewed focus on archosaur anatomy enable the compilation of a new dataset, which assimilates and standardizes character data pertinent to higher-level archosaur phylogeny, and is scored across the largest group of taxa yet analysed. This dataset includes 47 new characters (25% of total) and eight taxa that have yet to be included in an analysis, and total taxonomic sampling is more than twice that of any previous study. This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosauria and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Support values are low, suggesting rampant homoplasy and missing data within Archosauria, but the phylogeny is highly congruent with stratigraphy. Comparison with alternative analyses identifies numerous scoring differences, but indicates that character sampling is the main source of incongruence. The phylogeny implies major missing lineages in the Early Triassic and may support a Carnian-Norian extinction event.Marshall Scholarship for study in the United KingdomJurassic FoundationUniversity of BristolPaleontological Societ

Use of urease inhibitors to reduce ammonia volatilization in Amazonian soils.

Made available in DSpace on 2020-01-21T18:22:22Z (GMT). No. of bitstreams: 1 Barberenaetal.2019.pdf: 846211 bytes, checksum: 62a20ad6265f0815c390e4387cc19f9c (MD5) Previous issue date: 2019bitstream/item/209268/1/Barberena-et-al.-2019.pd

Paleoenvironmental and paleoclimatic dynamics of the Subtropical Andes of Argentina (35° S) during the last 3000 years

The most recent IPCC report indicated that the Subtropical Andes (32 degrees-35 degrees S) are one of the world areas undergoing a strong tendency towards more arid conditions due to current climate change. The winter precipitation that falls on the Andes, related to the Southern Westerlies System (SWS), is the main source of water for central Chile and west central Argentina, making it a fundamental socioeconomic resource. The few long-term records of the eastern slope of the Subtropical Andes do not permit establishing the long-term natural climate variability or determining if this trend does or does not respond to natural forcings. This study therefore presents a centennial and sub-centennial scale reconstruction of the paleoenvironmental dynamics of the eastern slope of the Subtropical Andes during the last 3000 cal yrs BP, based on the pollen record of the Laguna Coraz & oacute;n (LCO; 35.13 degrees S; 2200 m a.s.l.), in order to establish the different regional paleoenvironmental scenarios. The sedimentary record (182 cm) is mostly composed of laminated dark brown clay, and includes a 21-24 cm layer preliminarily associated with the 1932 AD eruption of the Quizap & uacute; volcano. The LCO record shows the development of a grass steppe associated with high-Andean shrubs between 3000 and 2440 cal yrs BP, suggesting slightly more humid conditions than present. From 2440 to 1110 cal yrs BP, there was continuous presence of the grass steppe along with high-Andean and Patagonian low shrubs, indicating moderately more humid conditions than today. The development of a grass steppe with low high-Andean shrubs from 1110 to 320 cal yrs BP reflects conditions slightly more humid that at present, showing a progressive decrease in humidity between 900 and 320 cal yrs BP. Since then, environmental conditions were similar to present ones, associated with the climatic variability at sub-centennial timescale. In the last 320 cal yrs BP, the record shows the presence of introduced species as a consequence of the occupation of the valley to raise livestock, and more recently, tourist activities. These environmental/climatic patterns are similar to those recorded for the western slope of the Subtropical Andes for the Late Holocene, indicating a regional forcing related to the winter precipitation associated with the SWS

Temporomandibular joint osteoarthritis in human ancient skeletal remains from Late Holocene in southern Patagonia

Low prevalence of caries, high stages of dental attrition (DA), and moderate frequency of antemortem tooth loss (AMTL) were found in skeletal remains of hunter-gatherers from southern Patagonia. However, osteoarthritis (OA) of temporomandibular joint (TMJ), possible related to oral health, has not been studied so far. The influence of hunter-gatherer living conditions on the development of TMJ-OA was scarcely evaluated, and analyses of degenerative changes of TMJ in nonindustrialized groups are needed. The aim of this study is to analyse the association between degenerative changes of TMJ, oral disease, and palaeodietary patterns in skeletal remains of hunter-gatherers from southern Patagonia. Degenerative changes of TMJ were recorded in 25 adult skulls of both sexes. Eburnation of articular eminence and/or mandibular condyle was considered as pathognomonic of OA. In the absence of eburnation, OA was diagnosed when two or more of the following lesions were identified: (a) new bone formation on joint surface, (b) new bone formation of joint margins, (c) porosity on the joint surface, and (d) modification of joint contour. In the studied skeletons, it was found that OA prevalence is 28%, similar to those observed in other hunter-gatherer populations elsewhere. TMJ-OA is mostly related to AMTL and older age, but no relation was found with caries and DA, sex, region, dietary patterns, and chronology. However, consumption of terrestrial resources in the diet cannot be discarded as a related factor. Further studies are necessary to explore the morphological variability of the mandible and its possible relationship with different diets and dental pathologies in these populations.Fil: Suby, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Giberto, Diego Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin