36 research outputs found

    Multiple logistic regressions: controlling factors in applications to soil class prediction.

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    Métodos mais eficazes para determinação do padrão de distribuição de classes de solo na paisagem precisam ser avaliados visando suprir a demanda por mapas de solo em escalas regional e global. Neste estudo, Regressões Logísticas Múltiplas foram utilizadas como modelos preditores em uma aplicação de Mapeamento Digital de Solos. Os modelos foram gerados utilizando um mapa de solos existente como variável dependente e atributos de terreno como variáveis independentes, o que possibilitou determinar a probabilidade de encontrar classes de solo na paisagem no primeiro e no segundo nível categórico do SiBCS. A qualidade dos mapas preditos foi verificada por meio da matriz de contingência. A classe dos Argissolos foi predita corretamente, em relação ao mapa original, em aproximadamente 85 %. As classes de solos hidromórficos (Planossolos e Gleissolos) foram preditas corretamente em 75 %. Houve confundimento dos modelos para as classes que ocupam posições muito semelhantes na paisagem. Foi verificado também que classes de solo pouco representativas na paisagem não são adequadamente espacializadas em razão da sensibilidade dos modelos logísticos à proporção relativa das amostras usadas para treinar os modelos

    Overcoming barriers towards Sustainable Product-Service Systems in Small and Medium-sized enterprises: State of the art and a novel Decision Matrix

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    The Sustainable Product-Service Systems are a promising approach based on a Triple Bottom Line perspective of the sustainability. However, its practical and effective adoption is still very limited and addresses significant barriers for the manufacturing firms. Furthermore, this emergent topic has been discussed by literature mainly in large company's context, turning in a very limited and immature stage the current body of knowledge for the Small and Medium-sized Enterprises (SMEs). Thus, considering the significance of small companies to the global economy and their intrinsic difficulties, the purpose of this study was to identify the main barriers involving the transition towards Sustainable Product-Service Systems in manufacturing Small and Medium-sized Enterprises as well as the strategies to overcome them. A systematic literature review of the past two decades was organized capturing the state of the art of the area. Findings reveal that internal barriers associated with intrinsic characteristics of SMEs become still more sensitive during the transition (e.g., limited financial resources, the lack of competences, follower mentality and resistance to change). As well as, barriers related with the novelty of Sustainable Product-Service Systems models require new attitudes to small companies (e.g., changing mindsets from product ownership to use, replacing the value of exchange by value in use involving long-term relations, understanding the Product-Service Systems concept) and particularly highlight the lack of models/methods supporting this transition. The practical contribution of this study is in organise a comprehensive body of knowledge on strategies to overcome barriers towards Sustainable Product-Service offering. Moreover, an innovative decision matrix supporting decision-makers during the Sustainable Product-Service System development was proposed from the literature review findings. (C) 2019 Elsevier Ltd. All rights reserved

    In‐plane shear strength of single‐lap co‐cured joints of self‐reinforced polyethylene composites

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    The present study introduces the analysis of single‐lap co‐cured joints of thermoplastic self‐reinforced composites made with reprocessed low‐density polyethylene (LDPE) and reinforced by ultra‐high‐molecular‐weight polyethylene (UHMWPE) fibers, along with a micromechanical analysis of its constituents. A set of optimal processing conditions for manufacturing these joints by hot‐press is proposed through a design of experiment using the response surface method to maximize their in‐plane shear strength by carrying tensile tests on co‐cured tapes. Optimal processing conditions were found at 1 bar, 115 °C, and 300 s, yielding joints with 6.88 MPa of shear strength. The shear failure is generally preceded by multiple debonding‐induced longitudinal cracks both inside and outside the joint due to accumulated transversal stress. This composite demonstrated to be an interesting structural material to be more widely applied in industry, possessing extremely elevated specific mechanical properties, progressive damage of co‐cured joints (thus avoiding unannounced catastrophic failures) and ultimate recyclability

    Los caminhos de la calidad, un estudio sobre la visión de expertos y productores rurales a respeto de procesos y tecnologías.

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    The production of special coffees consists of an art, employing different management and production and processing systems, to obtain the most advantageous results regarding final product quality. Several factors interact during the production cycle being, almost always, essential to obtain a product with better quality or, on the other hand, for its deterioration. This work aims to study and quantify the perception of the degree of importance of various forms and methods for the production of special coffees, from producers and experts, in the mountain regions of Espírito Santo. As methodology to understand the processes adopted by producers and indicated by experts, we used a questionnaire with closed questions, being the questionnaire validated by Cronbach's Alpha. After instrument validation, data were analyzed by t test, for analysis and comparison of the studied groups. The results indicate that some processes have no homogeneity between experts and producers of special coffees, indicating gaps which need to be better understood and studied. The harvest, wet processing, storage and technical assistance constructs were more homogeneous among the studied group, indicating that various techniques are rooted between experts and producers of special coffees

    Assembly of the 373k gene space of the polyploid sugarcane genome reveals reservoirs of functional diversity in the world's leading biomass crop

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    BACKGROUND: Sugarcane cultivars are polyploid interspecific hybrids of giant genomes, typically with 10-13 sets of chromosomes from 2 Saccharum species. The ploidy, hybridity, and size of the genome, estimated to have >10 Gb, pose a challenge for sequencing. RESULTS: Here we present a gene space assembly of SP80-3280, including 373,869 putative genes and their potential regulatory regions. The alignment of single-copy genes in diploid grasses to the putative genes indicates that we could resolve 2-6 (up to 15) putative homo(eo)logs that are 99.1% identical within their coding sequences. Dissimilarities increase in their regulatory regions, and gene promoter analysis shows differences in regulatory elements within gene families that are expressed in a species-specific manner. We exemplify these differences for sucrose synthase (SuSy) and phenylalanine ammonia-lyase (PAL), 2 gene families central to carbon partitioning. SP80-3280 has particular regulatory elements involved in sucrose synthesis not found in the ancestor Saccharum spontaneum. PAL regulatory elements are found in co-expressed genes related to fiber synthesis within gene networks defined during plant growth and maturation. Comparison with sorghum reveals predominantly bi-allelic variations in sugarcane, consistent with the formation of 2 "subgenomes" after their divergence approximately 3.8-4.6 million years ago and reveals single-nucleotide variants that may underlie their differences. CONCLUSIONS: This assembly represents a large step towards a whole-genome assembly of a commercial sugarcane cultivar. It includes a rich diversity of genes and homo(eo)logous resolution for a representative fraction of the gene space, relevant to improve biomass and food production
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