Le varietà di sorgo da granella consigliate per le semine 2017

Nel 33º anno di prove di confronto tra ibridi di sorgo da granella sono stati realizzati 5 campi sperimentali, 2 nel Nord, 2 in Italia centrale e 1 in Sicilia. Le rese medie sono risultate simili a quelle del 2015, pur con notevoli differenze tra i diversi areali di coltivazion

Functional diversity of marine ecosystems after the Late Permian mass extinction event

Article can be accessed from http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2079.htmlThe Late Permian mass extinction event was the most severe such crisis of the past 500 million years and occurred during an episode of global warming. It is assumed to have had significant ecological impact, but its effects on marine ecosystem functioning are unknown and the patterns of marine recovery are debated. We analysed the fossil occurrences of all known Permian-Triassic benthic marine genera and assigned each to a functional group based on their inferred life habit. We show that despite the selective extinction of 62-74% of marine genera there was no significant loss of functional diversity at the global scale, and only one novel mode of life originated in the extinction aftermath. Early Triassic marine ecosystems were not as ecologically depauperate as widely assumed, which explains the absence of a Cambrian-style Triassic radiation in higher taxa. Functional diversity was, however, significantly reduced in particular regions and habitats, such as tropical reefs, and at these scales recovery varied spatially and temporally, probably driven by migration of surviving groups. Marine ecosystems did not return to their pre-extinction state, however, and radiation of previously subordinate groups such as motile, epifaunal grazers led to greater functional evenness by the Middle Triassic

Macrofossil evidence for a rapid and severe Cretaceous–Paleogene mass extinction in Antarctica

Debate continues about the nature of the Cretaceous–Paleogene (K–Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K–Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous–Paleogene succession: the López de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian

Enteric methane emissions by goats in grazing in caatinga.

Caatinga is an important food source for the animals of the semi-arid region, but the low quality forage at certain times of year limits animal performance and increases the emission of methane gas. Thus, the objective of this study was to evaluate the forage intake and emission of methane by goats fed grassland savanna during two periods of the year

Emissão de gases de efeito estufa em sistemas produtivos no Nordeste brasileiro.

Apesar de o efeito estufa ser um fenômeno que ocorre naturalmente na atmosfera terrestre e que está associado à manutenção da temperatura média do planeta em uma faixa adequada às formas de vida que se conhece, o crescente aumento da concentração de gases de efeito estufa (GEEs) na atmosfera em função de atividades humanas, intensificado desde o início da Revolução Industrial, tem elevado a temperatura média no planeta e pode ter consequências econômicas e ambientais desastrosas. As emissões brasileiras de GEEs em 2017 foram estimadas em 2.070 Mt de CO2 -eq (SEEG, 2018). Desse valor, 23,9% são oriundos da atividade agropecuária, principalmente em função da criação de animais em pastagens e do uso de fertilizantes sintéticos

Intraflagellar transport dynein is autoinhibited by trapping of its mechanical and track-binding elements

Cilia are multi-functional organelles that are constructed using intraflagellar transport (IFT) of cargo to and from their tip. It is widely held that the retrograde IFT motor, dynein-2, must be controlled in order to reach the ciliary tip and then unleashed to power the return journey. However, the mechanism is unknown. Here, we systematically define the mechanochemistry of human dynein-2 motors as monomers, dimers, and multi-motor assemblies with kinesin-II. Combining these data with insights from single-particle electron microscopy, we discover that dynein-2 dimers are intrinsically autoinhibited. Inhibition is mediated by trapping dynein-2’s mechanical “linker” and “stalk” domains within a novel motor-motor interface. We find that linker-mediated inhibition enables efficient transport of dynein-2 by kinesin-II in vitro. These results suggest a conserved mechanism for autoregulation among dimeric dyneins, which is exploited as a switch for dynein-2’s recycling activity during IFT

Efeito do recobrimento com manta térmica aluminizada sobre a temperatura interna de câmaras estáticas para amostragem de gases de efeito estufa emitidos pelo solo.

O objetivo desse trabalho foi avaliar se o revestimento externo das câmaras estáticas com material isolante afeta significativamente a temperatura interna das câmaras durante a coleta de amostras de GEE emitidos pelo solo

Caracterização e estoques de carbono do solo no Sistema Silvipastoril de produção de caprinos da Embrapa Semiárido (Sistema CBL).

Neste trabalho são apresentados resultados de pesquisas relacionadas à caracterização do solo em uma área pertencente à Embrapa Semiárido na qual foi implantado um estudo com o sistema CBL, que é uma estratégia importante não apenas pelo aporte alimentar para os rebanhos, como também para reduzir a pressão sobre os recursos da Caatinga, que é um bioma que vem sendo destacado como um dos mais degradados, apesar da realização de muitos estudos que objetivam a sua preservação.bitstream/item/214304/1/Caracterizacao-e-estoques-de-carbono-do-solo-2020.pd

Coconut residues increase light fraction of organic matter and water retention in semi-arid sandy soil under irrigated cultivation.

Coconut palm cultivation is associated with the generation of a large amount of residues, mainly from coconut shells, and their utilization in agriculture can represent an opportunity in the context of circular economy and climate change. This study aimed to determine the effect of coconut shell deposition on carbon (C) stocks, organic matter quality, and soil water retention in coconut palm cultivation in the Brazilian semi-arid region. The study was conducted in a commercial coconut palm cultivation area in Petrolina, Pernambuco State, Brazil, forming a chronosequence with 0, 2, 4, 5 and 6 years of coconut shells or coconut leaves application on soil surface. Carbon contents and stocks up to 0.40 m deep, the physical quality of soil organic matter, and soil water retention were evaluated. Coconut leaves and coconut shells increased organic C content in the surface layers of the soil, but the addition of residues did not influence soil C stocks. The light fraction of organic matter (>53 µm) was more sensitive to the management studied, while the heavy fraction of organic matter (53 µm and the highest soil water retention were observed three years after the deposition of coconut shells on the surface, which suggests the need for reapplying the residues after this period to maintain the benefits

Frações físicas de matéria orgânica em solo cultivado com palma forrageira sob diferentes quantidades de palhada de capim buffel.

Este trabalho teve por objetivo determinar os efeitos da adição de palha de capim-buffel como cobertura morta sobre as frações da matéria orgânica do solo