Um método para determinar o volume comercial do Schizolobium amazonicum (Huber) ducke utilizando redes neurais artificiais.

Este trabalho apresenta um método para determinar o volume comercial do Schizolobium amazonicum (Huber) Ducke, com casca, utilizando Redes Neurais Artificiais (RNAs). Compara os resultados com estimativas obtidas pelo método de regressão linear e quadrática. O modelo neural artificial utiliza uma RNA multicamada direta com uma camada intermediária e, o algoritmo de treinamento supervisionado backpropagation. Os resultados obtidos pelo modelo neural foram mais próximos do real que os obtidos pelos métodos de regressão linear e quadrática. O erro médio absoluto obtido pela RNA foi aproximadamente 50% menor quando comparado com o obtido pelo modelo de regressão quadrática e o erro padrão da estimativa cerca de 30% menor do que os obtidos pelos modelos de regressão linear e quadrática. Com o uso do modelo neural, não foi necessário utilizar o fator de forma, já que este varia de acordo com a idade, diâmetro e altura das árvores

Determinação dos constituintes do leite de vacas de corte de acordo com o período de lactação.

SIEPE. Online

Micropropagação de Kiwizeiros Actinidia arguta, Actinidia deliciosa e Actinidia chinensis.

A publicação apresenta o protocolo de micropropagação ajustado para as principais variedades de kiwi cultivadas no Sul do Brasil, visando a produção de mudas de qualidade e livres de patógenos, bem como desonerar e abreviar o protocolo para emprego em escala comercial. Foram testadas simultaneamente as etapas de enraizamento e aclimatização de mudas de Actinidia arguta, A. deliciosa e A. chinensis.bitstream/item/214573/1/CIRCULAR-TECNICA-150-PUBLICA-487-versao-2020-07-09.pd

Al2O3 preforms infiltrated with poly(methyl methacrylate) for dental prosthesis manufacturing

The combination of biocompatible polymers and ceramics shows great promise in the development of composites with suitable mechanical properties for dental applications. In an attempt to further expand this research line, Al2O3 commercial powders (Vitro-ceram, Alglass, In-ceram) were sintered at 1400◦C for 2 h and infiltrated with poly(methyl methacrylate) for potential use in dental prostheses. The infiltration was performed using a homemade apparatus under a pressure of 7 bar for 6 and 12 h. The microstructure (studied using a scanning electron microscope), Archimedes density, 3-point bending flexural strength and Vickers hardness of the prepared composites were assessed and quantitatively compared. In general, microstructural analyses showed ceramic-and polymer-based interpenetrating network in all materials. The preforms infiltrated for 12 h showed superior properties; among them, the Vitro-ceram-based composite also demonstrated a near-zero open porosity and optimum mechanical characteristics. Specifically, its density, strength and hardness were 2.6 ± 0.07 g/cm3, 119.3 ± 5.0 MPa and 1055.1 ± 111.0 HV, respectively, passing the acceptance criteria of ISO 6872 and making it suitable for consideration as a metal-free structure for dental crowns and fixed partial prostheses until three anterior units

Vinte anos de integração pesquisa-extensão-agricultor com feijão no Rio Grande do Sul.

bitstream/item/58268/1/7-feijao-Iraja-2011.pd

Capacidade de retenção de água em amostras de diferentes horizontes de solo na Bacia do Rio Urucu - Amazonas.

O objetivo deste trabalho foi avaliar a retenção de água em sete potenciais, estimar a água disponível e avaliar a densidade do solo nos horizontes de cinco perfis em áreas de floresta primária na Base de Operações Geólogo Pedro de Moura - Urucu - AM

Strategies to mitigate the emission of methane in pastures: Enteric methane: A review

The global population reached 7.9 billion in 2021, which represents a 160% increase in the number of people to be fed since 1960. Agricultural systems must sustainably meet food demand for this growing population while minimizing or mitigating potential environmental impacts, which are of growing concern to both consumers and the scientific community. High protein animal products (meat and milk) play a crucial part in human nutrition and pastures represent ~20% of the planet’s surface. Pastoral areas have a great influence on both ecological balance and human subsistence. Ruminant livestock production systems are hotly debated because of the emission of methane, which is produced during enteric fermentation of ingested food within the rumen. Methanogenesis is a naturally occurring process in the digestive system of ruminant animals and ingesting a high-quality diet has been shown to reduce methane production. An additional function of pastoral grasslands is the capacity of the soils to operate as carbon sinks. Well managed pastures absorb carbon from the atmosphere where it can add to soil organic matter directly, through residue decomposition or excrement returns. However, in Brazil and globally, the efficiency of animal productivity tends to be lower in extensively grazed farming systems. Changes to pasture and grazing management in combination with the adoption of technology is necessary to improve the quality of pastures, increase animal productivity, and consequently reduce methane emissions from ruminant livestock. This review will discuss how to improve the conversion efficiency using pasture management to reduce or mitigate enteric methane production