163 research outputs found

    Foliar application of silicon and the effect on wheat seed yield and quality.

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    ABSTRACT: Adequate nutrients for plants are important for increasing the yield and quality of the seeds produced. The objective of this study was to evaluate foliar fertilization with silicon in wheat and its effect on seed yield and physiological quality. Treatments consisted of two silicon dosages (three and six liters silicon per hectare) and the control (no silicon) and five wheat cultivars: OR "Quartzo", OR "Ônix", Fundacep "Linhagem", Fundacep "Campo Real" and Fundacep "Horizonte". The experimental design was randomized blocks with four replications. After physiological maturity, harvesting and threshing of the seeds were done manually. Seed samples were evaluated for yield and physiological quality from the germination test, first germination count, seedling dry weight, accelerated aging, electrical conductivity, 1000 seeds and hectoliter weights. The results showed that the foliar application of silicon at the dosages tested did not affect the yield and physiological quality of the seeds produced by the wheat cultivars. RESUMO: A disponibilidade adequada de nutrientes às plantas é de fundamental importância tanto para incrementos em rendimento bem como, para a produção de sementes de elevada qualidade. Dessa forma, objetivou-se com esse trabalho avaliar o efeito da adubação foliar com silício em trigo, no rendimento e na qualidade fisiológica das sementes produzidas. Os tratamentos consistiram de duas doses de silício aplicados via foliar (três e seis litros de silício por hectare), além da testemunha (sem aplicação do produto). Foram utilizadas cinco cultivares de trigo (OR "Quartzo", OR "Ônix", Fundacep "Linhagem", Fundacep "Campo Real" e Fundacep "Horizonte"). O delineamento experimental foi blocos ao acaso, com quatro repetições. Após a maturidade fisiológica, efetuou-se a colheita e a debulha das sementes de forma manual. Posteriormente, as amostras foram encaminhadas ao laboratório de análise de sementes onde foram efetuadas as avaliações do rendimento e da qualidade das sementes, por meio dos testes de germinação, primeira contagem da germinação, massa seca de plântulas, envelhecimento acelerado, condutividade elétrica, massa de mil sementes e massa hectolitro. A aplicação de silício, nas cultivares de trigo e nas doses testadas, não afeta o rendimento nem a qualidade fisiológica das sementes produzidas

    Phylogenetic diversity of Amazonian tree communities

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    This is the peer reviewed version of the following article: Honorio Coronado, E. N., Dexter, K. G., Pennington, R. T., Chave, J., Lewis, S. L., Alexiades, M. N., Alvarez, E., Alves de Oliveira, A., Amaral, I. L., Araujo-Murakami, A., Arets, E. J. M. M., Aymard, G. A., Baraloto, C., Bonal, D., Brienen, R., Cerón, C., Cornejo Valverde, F., Di Fiore, A., Farfan-Rios, W., Feldpausch, T. R., Higuchi, N., Huamantupa-Chuquimaco, I., Laurance, S. G., Laurance, W. F., López-Gonzalez, G., Marimon, B. S., Marimon-Junior, B. H., Monteagudo Mendoza, A., Neill, D., Palacios Cuenca, W., Peñuela Mora, M. C., Pitman, N. C. A., Prieto, A., Quesada, C. A., Ramirez Angulo, H., Rudas, A., Ruschel, A. R., Salinas Revilla, N., Salomão, R. P., Segalin de Andrade, A., Silman, M. R., Spironello, W., ter Steege, H., Terborgh, J., Toledo, M., Valenzuela Gamarra, L., Vieira, I. C. G., Vilanova Torre, E., Vos, V., Phillips, O. L. (2015), Phylogenetic diversity of Amazonian tree communities. Diversity and Distributions, 21: 1295–1307. doi: 10.1111/ddi.12357, which has been published in final form at 10.1111/ddi.12357Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities.FINCyT - PhD studentshipSchool of Geography of the University of LeedsRoyal Botanic Garden EdinburghNatural Environment Research Council (NERC)Gordon and Betty Moore FoundationEuropean Union's Seventh Framework ProgrammeERCCNPq/PELDNSF - Fellowshi

    Phylogenetic diversity of Amazonian tree communities

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    Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities

    Distribuição espacial de danos de percevejo em campos de produção de sementes de soja.

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    RESUMO: Estudos tem demonstrado que a qualidade fisiológica de sementes de soja nos campos de produção apresenta variabilidade espacial. Uma das possíveis causas dessa variabilidade, pode ser o ataque localizado de pragas, principalmente percevejos. O objetivo do trabalho foi determinar a distribuição espacial dos danos de percevejos em sementes de soja nos campos de produção de sementes e o seu efeito na qualidade fisiológica. O trabalho foi desenvolvido em quatro campos de produção de sementes na safra 2011/12, na região central do Estado do Rio Grande do Sul, Brasil. Para a coleta das amostras, foi estabelecida uma malha de amostragem com densidade de 1:0,10; 1:0,25; 1:0,10 e 1:0,25 pontos/ha, sendo a área total dos campos de 4,3; 11,4; 5,9 e 12,7ha e as cultivares NA 5909 RG, BMX Turbo RR, NA 5909 RG e NA 4725 RG, respectivamente. Foram realizadas as seguintes determinações: produtividade, teste de germinação, primeira contagem, emergência de plântulas e teste de tetrazólio. Os dados gerados foram utilizados para a elaboração de modelos digitais (mapas) através do software ?Sistema Agropecuário CR - Campeiro 7?. Os danos causados por percevejos em sementes de soja apresentam variabilidade espacial nos campos de produção e os dados são correlacionados a uma distância mínima de 200m. Os ataques de percevejos reduzem a viabilidade e o vigor de sementes de soja em diferentes intensidades dentro dos campos de produção. ABSTRACT: Studies have shown that the physiological quality of soybean seed production fields presents spatial variability. One of the possible causes of this variability can be localized attack of pests, especially stink bugs. The goal of this study was to determine the spatial distribution of stink bug damage in soybean seeds in seed production fields and their effect on physiological quality. The study was conducted in four seed production fields in the 2011/12 season, in the central region of Rio Grande do Sul, Brazil. For sample collection, a sampling grid with density of 1:0.10, 1:0.25, 1:0.10, 1:0.25 points/ ha was established, with total area of the fields of 4.3, 11.4, 5.9 and 12.7ha and cultivars NA 5909 RG, BMX Turbo RR, NA 5909 RG and NA 4725 RG, respectively. The following determinations were made: productivity, germination test, first count, seedling emergence and tetrazolium test. The generated data were used for the development of digital models (maps) using the ?System Agricultural CR - Campeiro 7? software. Damage caused by stink bugs in soybean seeds exhibit spatial variability in production fields and the data are correlated at a minimum distance of 200m. The attacks of stink bug reduce the viability and vigor of soybean seeds at different intensities within the fields of production. RESUMEN: Estudios anteriores han demostrado que la calidad fisiológica de las semillas de soya en los campos de producción presenta variabilidad espacial. Una de las causas posibles de tal variabilidad puede ser el ataque localizado de plagas, principalmente de chinches. El objetivo del presente trabajo fue determinar la distribución espacial de los daños por chinches en semillas de soya en los campos de producción de semillas y su efecto en la calidad fisiológica. El trabajo fue llevado a cabo en cuatro campos de producción de semillas en la zafra 2011/2012, en la región central del estado de Rio Grande del Sur, Brasil. Para la recolección de muestras se estableció una malla de muestreo con densidades de 1:0,10; 1:0,25; 1:0,10 y 1:0,25 puntos/ha, siendo el área total de los campos de 4,3; 11,4; 5,9 e 12,7ha y los cultivares NA 5909 RG, BMX Turbo RR, NA 5909 RG e NA 4725 RG, respectivamente. Fueron realizadas las siguientes determinaciones: productividad, prueba de germinación, primer contaje, emergencia de plántulas y test de tetrazolio. Los datos obtenidos fueron utilizados para la elaboración de modelos digitales (mapas) por medio del logicial ? Sistema Agropecuario CR - Campeiro 7?. Los daños causados por chinches en semillas de soya presentan variabilidad espacial en los campos de producción y los datos se correlacionan una distancia mínima de 200m. Los ataques de chinches reducen la viabilidad y el vigor de las semillas de soya en diversos grados en los campos de producción

    How smart does your profile image look? Estimating intelligence from social network profile images

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    Profile images on social networks are users' opportunity to present themselves and to affect how others judge them. We examine what Facebook images say about users' perceived and measured intelligence. 1,122 Facebook users completed a matrices intelligence test and shared their current Facebook profile image. Strangers also rated the images for perceived intelligence. We use automatically extracted image features to predict both measured and perceived intelligence. Intelligence estimation from images is a difficult task even for humans, but experimental results show that human accuracy can be equalled using computing methods. We report the image features that predict both measured and perceived intelligence, and highlight misleading features such as "smiling'' and "wearing glasses'' that are correlated with perceived but not measured intelligence. Our results give insights into inaccurate stereotyping from profile images and also have implications for privacy, especially since in most social networks profile images are public by default

    Tropical forests in the Americas are changing too slowly to track climate change

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    Understanding the capacity of forests to adapt to climate change is of pivotal importance for conservation science, yet this is still widely unknown. This knowledge gap is particularly acute in high-biodiversity tropical forests. Here, we examined how tropical forests of the Americas have shifted community trait composition in recent decades as a response to changes in climate. Based on historical trait-climate relationships, we found that, overall, the studied functional traits show shifts of less than 8% of what would be expected given the observed changes in climate. However, the recruit assemblage shows shifts of 21% relative to climate change expectation. The most diverse forests on Earth are changing in functional trait composition but at a rate that is fundamentally insufficient to track climate change

    Global maps of soil temperature

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0\u20135 and 5\u201315 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10\ub0C (mean = 3.0 \ub1 2.1\ub0C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 \ub1 2.3\ub0C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler ( 120.7 \ub1 2.3\ub0C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

    Global maps of soil temperature.

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km <sup>2</sup> resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km <sup>2</sup> pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
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