101 research outputs found

    SYNTHETIC POLYMERS ON WATER RETENTION AND PORE DISTRIBUITION IN A CLAYEY LATOSOL

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    The use of polymers is growing at the agricultural area, however their effects on soil porosity have been little studied. The objective of this article is to analyze the effects of applied synthetic polymers on soil porosity and water retention of a Dystroferric red Latosol. This study was conducted on undisturbed samples collected at a depth of 0.05m in a Latosol beneath native forest. The samples were saturated with distilled water and polymers HyC, HyA, HyB diluted in water according to use recommendations for coffee plantations. These samples were then submitted to matric potentials of -2, -4, -6 and -10 kPa in the suction units and -33, -100, -500 and -1500 kPa in a Richards extractor. Water retention curves were moldeled and pore size distribution estimates calculated. The data were subjected to variance analysis and the averages were compared using the Scott-knott test to a level of 5%. There was a reduction of the pore volume of size class larger than 145µm when the soil was saturated with HyA and HyB polymers. On one hand the HyB polymer promoted a reduction in the pore volume in the intermediate classes (2.9-0.6; 0,.-0.2 µm), that were responsible for providing water to the plants. On the other hand the HyC polymer promoted an increase in the soil water retention

    Fertilidade do solo e estado nutricional do cafeeiro cultivado em atmosfera enriquecida com CO2

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    The objective of this work was to evaluate the effects of atmospheric CO2 levels on soil chemical attributes, in rows (coffee crop) and between rows (Urochloa decumbens), and on macronutrient contents in coffee leaves. A randomized complete block design was used, in a split‑plot, with six replicates. The treatments consisted of two CO2 levels in the atmosphere, 390 and 550 μmol mol‑1. Soil samples were collected in and between coffee rows in 2013 and 2014, at the soil layers of 0–5.0, 5.0–10, 10–20 and 20–40 cm, and of 0–10, 10–20 and 20–40 cm, respectively. Soil pH, Ca2+, Mg2+, available K, P, and S contents, base saturation, and soil organic matter were evaluated. In 2013 and 2014, a reduction in available P contents was observed in coffee rows as the CO2 levels in the air were increased. In 2014, soil available K contents were reduced and K contents in coffee leaf were increased under 550 μmol mol‑1 CO2. In coffee grown in atmosphere enriched with CO2, soil available P content is more reduced, which indicates the need of an adequate replacement of this nutrient.O objetivo deste trabalho foi avaliar os efeitos de concentrações de CO2 atmosférico nos atributos químicos do solo, na linha (cafeeiro) e na entrelinha (braquiária), e nos teores de macronutrientes em folhas do cafeeiro. Utilizou-se o delineamento de blocos ao acaso, com parcelas subdivididas e seis repetições. Os tratamentos consistiram de dois níveis de CO2 atmosférico, 390 e 550 μmol mol-1. A amostragem de solo foi realizada na linha e na entrelinha do cafeeiro, em 2013 e 2014, nas camadas de 0–5,0, 5,0–10, 10–20 e 20–40 cm, e de 0–10, 10–20 e 20–40 cm, respectivamente. Avaliaram-se pH, teores de Ca2+, Mg2+, K, P e S disponíveis, saturação por bases e matéria orgânica do solo. Em 2013 e 2014, houve redução nos teores de P na linha do cafeeiro, com o aumento da concentração de CO2. Em 2014, houve redução nos teores de K disponível no solo e aumento dos teores de K na folha do cafeeiro sob 550 μmol mol-1 de CO2. Em cafeeiro cultivado em atmosfera enriquecida com CO2, o teor de P disponível no solo é o que mais reduz, o que indica a necessidade de reposição adequada deste nutriente

    Soil Management and Water-Use Efficiency in Brazilian Coffee Crops

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    Brazil is a world leader in coffee production. However, currently, it coexists with recurrent and severe droughts, accompanied by intense heat, strong insolation and low relative humidity. As the cultivation is carried out primarily in the rainy season, these world climate variations have affected crops yields and fruits quality, requiring innovative actions that promote efficient use of water stored in the soil. Among several soil management practices that promote a more rational use of water, deep tillage combined with liming, gypsum and fertilizer amendments lead to an increase in effective depth of coffee roots, therefore reducing water stress. Moreover, intercropping with Urochloa sp. is highly efficient in enhancing soil structure, water infiltration and plant available water capacity. Additionally, other innovative techniques and practices are also introduced in this chapter

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    Alcoolismo em pacientes submetidos a cirurgia bariátrica: uma revisão sistemática: Alcoholism in patients undergoing bariatric surgery: a systematic review

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    A Cirurgia bariátrica tem sido uma opção de muitas pessoas que visam superar a obesidade e garantir qualidade de vida e saúde. No entanto, casos de complicações clínicas após operação tem ocorrido, sendo comum a incidência de alcoolismo. Este estudo teve como objetivo refletir sobre as causas da incidência de alcoolismo entre pacientes que foram submetidos a cirurgias bariátricas. Para o alcance dessa finalidade, realizou-se uma revisão sistemática de literatura, selecionando-se fontes das bases de dados Scielo Brasil, PubMed e Biblioteca Virtual em Saúde (BVS), publicados em língua portuguesa, nos anos de 2017 a 2022. Realizando-se a análise dos dados concluiu-se que o transtorno do uso de álcool em pessoas submetidas à cirurgia bariátrica tem sido recorrente, especialmente entre homens de baixa renda e que fizeram a cirurgia do tipo bypass gástrico. Observou-se também que o consumo de álcool é maior no pós-operatório e que boa parte dos pacientes que se submeteu a esse tipo de cirurgia ignorava o risco de desenvolver o referido transtorno. Em função disso, boa parte dos estudos que integraram esta revisão reconhece a necessidade do acompanhamento, pela equipe de saúde, dos pacientes logo após a cirurgia bariátrica e a adesão desses ao tratamento devido, visando prevenir o transtorno do uso de álcool

    Pervasive gaps in Amazonian ecological research

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    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
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