Tebuthiuron leaching in three Brazilian soils as affected by soil pH     

Autieres Teixeira Faria  Matheus Freitas Souza  Ana Beatriz Rocha de Jesus Passos  Antonio Alberto da Silva  Daniel Valadão Silva  José Cola Zanuncio  Paulo Roberto Ribeiro Rocha 《Environmental Earth Sciences》2018,77(5):214

Underground contamination water by herbicides depends on the interactions between their molecules with physical and chemical soil characteristics and climatic conditions. Studies with columns can estimate the leaching potential of herbicides in soils. This study aimed to determine the effect of soil pH on tebuthiuron leaching, and capacity of bioindicators to detect tebuthiuron residues in three Brazilian soils. Cucumber plants (Cucumis sativus) were more negatively affected when grown in soils with lower amounts of organic matter and clay, and in these soils, the tebuthiuron levels reached greater depths in the column. There was a positive correlation between tebuthiuron concentration and cucumber intoxication, and a negative correlation between tebuthiuron concentration and dry matter cucumber in all soils. The tebuthiuron leached up to 50 cm depth even in soils with higher organic matter and clay content. The increasing of soil pH can affect the leaching of nonionic herbicides, and liming practice may elevate the environmental contamination risk by tebuthiuron. The bioindicator method using Cucumis sativus is viable and can be recommended to detect tebuthiuron concentrations above 0.2 mg kg^?1.  相似文献   

Estimation of monthly global solar irradiation using the Hargreaves–Samani model and an artificial neural network for the state of Alagoas in northeastern Brazil     

Gustavo Bastos Lyra  Sidney Sára Zanetti  Anderson Amorim Rocha Santos  José Leonaldo de Souza  Guilherme Bastos Lyra  José Francisco Oliveira-Júnior  Marco Antônio Maringolo Lemes 《Theoretical and Applied Climatology》2016,125(3-4):743-756

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Use of spatial regression models in the analysis of burnings and deforestation occurrences in forest region,Amazon, Brazil     

Camil Wadih Salame  Joaquim Carlos Barbosa Queiroz  Gilberto de Miranda Rocha  Mario Miguel Amin  Edson Paulino da Rocha 《Environmental Earth Sciences》2016,75(3):274

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Biogeochemical coefficients as indicators of nutrient element sorption in jerivá (<Emphasis Type="Italic">Syagrus romanzoffiana</Emphasis> (Chamisso) Glassman), a palm tree species from Brazil     

Rosely Aparecida Liguori Imbernon  Rejane Gonçalves Rocha 《Environmental Earth Sciences》2016,75(6):515

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Measuring α in the Early Universe     

Graça Rocha 《Astrophysics and Space Science》2003,283(4):589-594

We update the bounds on a time-varying fine structure constant α at the time of BBN (z∼10¹⁰) and CMB (z∼10³) and present the current CMB constraints on α, through a combined analysis of the BOOMERanG, MAXIMA and DASI datasets. We also present a discussion of the constraints on α coming from large-scale structure observations, focusing in particular on the power spectrum from the 2dF survey. Finally we provide a analysis of the degeneracies between α and the other cosmological parameters and discuss ways to break these with both existing and/or forthcoming data. Our results are consistent with no variation in α from the epoch of recombination to the present day, and restrict any such variation to be less than about 4%.We show that the forthcoming MAP and Planck experiments will be able to break most of the currently existing degeneracies between α and other parameters, and measure α to better than percent accuracy. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Development of a drought vulnerability index using MCDM and GIS: study case in São Paulo and Ceará, Brazil     

de Azevedo Reis  Gabriela  de Souza Filho  Francisco Assis  Nelson  Donald Robert  Rocha  Renan Vieira  da Silva  Samiria Maria Oliveira 《Natural Hazards》2020,104(2):1781-1799

Natural Hazards - Although climate change vulnerability research in general has increased over the last decade, Latin American countries have more directed more limited efforts toward vulnerability...  相似文献   

Denitrification-nitrification process in permeable coastal sediments: An investigation on the effect of salinity and nitrate availability using flow-through reactors     

Shan Jiang  Mark Kavanagh  Juan Severino Pino Ibánhez  Carlos Rocha 《海洋学报(英文版)》2021,40(9):1-2

Permeable coastal sediments act as a reactive node in the littoral zone,transforming nutrients via a wide range of biogeochemical reactions.Reaction rates are controlled by abiotic factors,e.g.,salinity,temperature or solute concentration.Here,a series of incubation experiments,using flow-through reactors,were conducted to simulate the biogeochemical cycling of nitrate (NO_3~?) and phosphorus (P) in permeable sediments under differentNO_3~?availability conditions (factor I) along a salinity gradient (admixture of river and seawater,factor II).In an oligotrophic scenario,i.e.,unamendedNO_3~?concentrations in both river and seawater,sediments acted as a permanent net source ofNO_3~?to the water column.The peak production rate occurred at an intermediate salinity(20).IncreasingNO_3~?availability in river water significantly enhanced netNO_3~?removal rates within the salinity range of 0 to 30,likely via the denitrification pathway based on the sediment microbiota composition.In this scenario,the most active removal was obtained at salinity of 10.When both river and seawater were spiked with NO_3~?,the highest removal rate switched to the highest salinity (36).It suggests the salinity preference of theNO_3~?removal pathway by local denitrifiers (e.g.,Bacillus and Paracoccus) and thatNO_3~?removal in coastal sediments can be significantly constrained by the dilution relatedNO_3~?availability.Compared with the obtained variation forNO_3~?reactions,permeable sediments acted as a sink of soluble reactive P in all treatments,regardless of salinity andNO_3~?input concentrations,indicating a possibility of P-deficiency for coastal water from the intensive cycling in permeable sediments.Furthermore,the net production of dissolved organic carbon (DOC) in all treatments was positively correlated with the measuredNO_3~?reaction rates,indicating that the DOC supply may not be the key factor forNO_3~?removal rates due to the consumption by intensive aerobic respiration.Considering the intensive production of recalcitrant carbon solutes,the active denitrification was assumed to be supported by sedimentary organic matter.  相似文献   

Mapping the Risk of Burning in the Brazilian Amazon with the Use of Logistic Regression and Fuzzy Inference   总被引：1，自引：1，他引：0  

Camil Wadih Salame  Joaquim Carlos Barbosa Queiroz  Gilberto de Miranda Rocha  Mario Miguel Amin 《Mathematical Geosciences》2012,44(3):241-256

Through the PRODESDIGITAL Project, the National Institute for Space Research (INPE) has been mapping vegetal coverage in the Brazilian Legal Amazon using Landsat satellite images. INPE not only identifies deforested areas but also releases a daily map of burning areas. Burning is frequently used as the cheapest way to deforest, to clear areas for farming and to increase the soil’s fertility in a short period of time. In many instances, these fires get out of control and end up accidentally invading areas of forest exploited by the lumber industry, agricultural plantations and pastures. However, the deforestation and burning area maps alone are insufficient for monitoring and control on a regional scale. It is necessary to know in an analytical way how actions (deforestation and burnings) that characterize human occupation are occurring in a region. In this research, two methods are used that allow the inclusion of co-variation in the estimation of variables of interest: logistic regression, which is a statistical method that considers a categorical or discrete response variable and discrete and/or continuous co-variation; and fuzzy logic, which makes use of artificial intelligence methods to incorporate into computational models information based on the knowledge or experience of a specialist. In both methods, the response variable may be related to the probability of occurrence of the environmental variable under study.  相似文献   

Fast Radio Bursts as Crustal Dynamical Events Induced by Magnetic Field Evolution in Young Magnetars     

J.E.Horvath  P.H.R.S.Moraes  M.G.B.de Avellar  L.S.Rocha 《天文和天体物理学研究(英文版)》2022,(3):39-46

We revisit in this work a model for repeating Fast Radio Bursts based of the release of energy provoked by the magnetic field dynamics affecting a magnetar's cr...  相似文献   

Trend and teleconnection patterns in the climatology of extratropical cyclones over the Southern Hemisphere     

Michelle Simões Reboita  Rosmeri Porfírio da Rocha  Tércio Ambrizzi  Carolina Daniel Gouveia 《Climate Dynamics》2015,45(7-8):1929-1944

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