21 research outputs found

    Pervasive gaps in Amazonian ecological research

    Get PDF

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    A História da Alimentação: balizas historiográficas

    Full text link
    Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

    Properties of Pinus sp. pellets prepared after In-line pre-compaction with torrefaction

    Get PDF
    Pelletizing and torrefaction increase biomass energy density, generating a more homogeneous fuel with lower moisture, enabling it to burn in equipment with high energy efficiency. This work evaluated the quality of pellets made from wood particles that had been densified and torrefied in an extruder-type system. Particles of the Pinus sp. wood were torrefied at 200, 250, and 300 °C for six minutes and then compacted to produce pellets. The physical, chemical, and mechanical properties of these pellets were evaluated and compared with standard ones. Torrefaction modified the pellets properties by increasing ash, fixed carbon, higher heating value, and the energy density, while reducing the volatile matter and equilibrium moisture content. The mechanical durability of the pellets was lower than that defined by the European, German, and American standards. The torrefaction pre-compaction route with torrefied particles at a temperature of 300 °C was the most efficient for energetic use, compared to the in natura biomass. The latter has negative aspects such as great variation in size (length and diameter) and density besides high moisture contentinfo:eu-repo/semantics/publishedVersio

    Properties of Pinus sp. Pellets Prepared after In-line Pre-compaction with Torrefaction

    Get PDF
    Pelletizing and torrefaction increase biomass energy density, generating a more homogeneous fuel with lower moisture, enabling it to burn in equipment with high energy efficiency. This work evaluated the quality of pellets made from wood particles that had been densified and torrefied in an extruder-type system. Particles of the Pinus sp. wood were torrefied at 200, 250, and 300 °C for six minutes and then compacted to produce pellets. The physical, chemical, and mechanical properties of these pellets were evaluated and compared with standard ones. Torrefaction modified the pellets properties by increasing ash, fixed carbon, higher heating value, and the energy density, while reducing the volatile matter and equilibrium moisture content. The mechanical durability of the pellets was lower than that defined by the European, German, and American standards. The torrefaction pre-compaction route with torrefied particles at a temperature of 300 °C was the most efficient for energetic use, compared to the in natura biomass. The latter has negative aspects such as great variation in size (length and diameter) and density besides high moisture content
    corecore