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Microbiological study of showerhead waters from 10 beaches of great Lisboa and west regions of Portugal; Estudo microbiológico de chuveiros de 10 praias da grande Lisboa e oeste de Portugal

Costa, Maria do Céu; Oliveira, Eva; Pires, Catarina; Moleiro, Filipa; Capitia, Vanessa; Vida, Manuela
Fonte: Edições Lusófonas Publicador: Edições Lusófonas
Tipo: Artigo de Revista Científica
POR
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Muitas bactérias patogénicas podem interferir no sistema de distribuição de água formando agregados de biofilme. Com o objetivo de monitorizar a qualidade microbiológica da água dos chuveiros de praia, recolheram-se 24 amostras de água, 12 em janeiro e fevereiro, e outras 12 em junho de 2013, em 10 praias ao logo da costa Lisboa-Carcavelos a Foz do Arelho. As amostras foram colhidas em frascos Esterilizados de 500 mL contendo tiossulfato. Paralelamente foram feitas zaragatoas dos mesmos pontos de colheita, com o meio de transporte Tween 20, e mantidas entre 2 ºC e 4ºC. Os parâmetros microbiológicos analisados para as águas foram: quantificação de microrganismos a 22 ºC e 37 ºC, contagem dos coliformes totais e Escherichia coli, de Pseudomonas aeruginosa, de Estreptococos fecais e de Estafilococos totais e Estafilococos coagulase-positiva. A partir das zaragatoas fez-se o isolamento dos microrganismos que cresceram no meio de Nutriente Agar, com o intuito de se determinar os mesmos parâmetros microbiológicos pesquisados na água dos chuveiros. No geral, a qualidade da água é adequada, o que não exclui a necessidade de monitorização constante dos chuveiros de praia. Tendo em conta que no 2.º período de recolha das amostras houve invasões de plâncton nalgumas destas praias estudadas e muitos banhistas apresentaram erupções alérgicas...

Variabilidade da condutividade hidráulica do solo em valores fixos de umidade e de potencial matricial. ; Variability of soil hydraulic conductivity at fixed values of water content and pressure head.

Hurtado, Ana Lucia Berretta
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/03/2004 PT
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O conhecimento da condutividade hidráulica do solo é essencial para qualquer modelagem que envolva o movimento da água no solo. Além de variar com a umidade, a condutividade hidráulica do solo (K) apresenta alta variabilidade espacial, tanto em determinações no campo como no laboratório, podendo ser representada em função da umidade (θ) ou do potencial matricial (ψm). Conforme indica a Lei de Poiseuille, a condutância de poros individuais é altamente sensível ao seu diâmetro. Como a distribuição dos diâmetros de poros de um solo é descrita pela sua curva de retenção e o maior poro que contém água define o potencial matricial, a hipótese do presente trabalho é que, expressando-se K para um θ fixo, sua variabilidade é maior que para um ψm fixo. Para testar tal hipótese, foi conduzido um experimento empregando-se o método do perfil instantâneo sem evaporação (durante 1050 horas) e com evaporação (durante 401 horas) em períodos diferentes, obtendo-se a condutividade hidráulica não saturada em 48 baterias distanciadas de 1 m entre si e dispostas em linha reta em um Latossolo Vermelho-amarelo, dentro do Campus da Escola Superior de Agricultura “Luiz de Queiroz” – ESALQ/USP em Piracicaba/SP. Os valores de potencial matricial foram obtidos por tensiometria em cinco profundidades (de 0...

Análise da acurácia das estimativas de posicionamento do nível freático e dos teores de umidade do solo com o emprego dos métodos de sísmica de refração rasa e georadar a partir de um estudo no campus da USP, São Paulo/SP; Analyses of Accuracy of Estimates of Water Table Positioning and of Soil Water Contents by Using Shallow Seismic Refraction and Georadar from a Study at USP's Campus, São Paulo/SP

Paixão, Manuelle Santos Góis
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/05/2005 PT
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A pesquisa teve como objetivo integrar o método GPR (Ground Penetrating Radar) com a sísmica de refração, visando o mapeamento do N.A. e a estimativa do teor de umidade em uma área de estudos hidrogeológicos no campus da USP, assim como analisar a acurácia da medida dos dois métodos. Foram realizados ensaios geofísicos, granulométricos, de teor de umidade, do grau de saturação, do monitoramento do N.A. e acompanhamento dos índices pluviométricos em três períodos com variações sazonais no decorrer de um ano denominados período chuvoso (janeiro/2004); período intermediário (abril/2004) e período seco (setembro/2004). O mapeamento do N.A. com GPR foi feito com geometria multi-offset, com as antenas de freqüências centrais 50 MHz, 100 MHz e 200 MHz, sendo que as antenas de 100 MHz e 200 MHz foram as que caracterizaram o N.A., refletindo sua variação sazonal e mantendo a tendência prof. N.A. janeiro < prof. N.A. abril < prof. N.A. setembro. O emprego da sísmica de refração gerou maiores erros e ambigüidades na inversão dos dados. Neste estudo, a sísmica de refração não foi sensível às variações sazonais e, embora os resultados tenham se aproximado das observações diretas, não permitiram mapear a flutuação do N.A. entre os diferentes períodos. A estimativa do teor de umidade volumétrico pelo GPR foi obtida com duas metodologias diferentes que utilizaram a onda direta no solo. Foram empregadas antenas de 50 MHz...

Avaliação de uma sonda TDR helicoidal para a estimativa do teor de umidade de solos em campo e laboratório; Evaluation of a helicoidal TDR probe to estimate the soil water content in laboratory and in situ

Assis, Cleber Decarli de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/05/2008 PT
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Este trabalho de pesquisa apresenta a avaliação de uma sonda TDR helicoidal para estimar o teor de umidade dos solos, em diferentes profundidades, através da técnica da reflectometria no domínio do tempo (TDR). Essa sonda, desenvolvida especificamente para esse fim, foi devidamente calibrada em laboratório para diferentes tipos de solo. O processo de calibração consistiu na determinação da constante dielétrica aparente (Ka) e condutividade elétrica volumétrica (ECb) de um mesmo solo com diferentes teores de umidade. Posteriormente foram buscadas correlações entre Ka e o teor de umidade gravimétrico (w), obtido em estufa. São propostas correlações entre w e Ka, entre w e 'KA POT. 1/2' e entre teor de umidade volumétrico ('teta') e Ka. Também foram consideradas as correlações propostas por Yu e Drnevich (2004), visando estimar também a massa específica seca dos solos. Foram realizados ensaios de campo para a validação das equações de calibração. Os valores dos teores de umidade estimados através da técnica da reflectometria no domínio do tempo, tanto em laboratório como em campo, foram comparados com os valores de teor de umidade obtidos com o método da estufa. Com base nos resultados foram determinados os erros referentes às calibrações. Nos ensaios de campo...

Desenvolvimento de métodos analíticos em sistemas de soluções em fluxo empregando polifenol oxidase naturalmente imobilizada sobre tecidos vegetais; Development of analytical methodologies in flow injections systems employing polyphenoloxidase naturally immobilized on plant tissues

Lima, Antonio William Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/06/1998 PT
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Esta tese apresenta o desenvolvimento de metodologias analíticas em sistemas de solução em fluxo com detecção amperométrica e espectrofotométrica explorando a utilização de tecidos vegetais como fonte enzimática para a biocatálise de reações. Desempenhos satisfatórios foram obtidos com a utilização do mesocarpo fibroso do coco (Cocus nucifera, L.) e com a casca e/ou polpa de frutos da palmeira leque (Latania sp), fontes de polifenol oxidase. Uma metodologia, simples e rápida, para a determinação dos parâmetros bioquímicos da polifenol oxidase foi desenvolvida ao longo do presente trabalho com a enzima naturalmente imobilizada no tecido do coco, pela eliminação das etapas de extração e de purificação e associando-se análise em fluxo e espectrofotometria. Parâmetros cinéticos importantes como o efeito do pH, a constante de Michaelis-Menten (Km), a velocidade máxima (Vmax),a energia de ativação (Ea) e os parâmetros térmicos (valores D, z e Q10)foram determinados utilizando como substrato o catecol. A atividade relativa junto a diferentes substratos e o efeito de inibidores foram também avaliados. Aplicações envolvendo estes tecidos vegetais em reatores empacotados (associados com FIA) ou incorporados em eletrodos de pasta de carbono (medidas realizadas em batelada) para a determinação de produtos fenólicos como catecol...

Efeito da irrigação com efluente de esgoto rico em sódio em propriedades químicas e físico-hídricas de um Argissolo e produtividade de capim Tifton 85 no município de Lins; Effect of irrigation with sodium rich sewage effluent in chemical, physical and hydraulic properties of an Ultisol and productivity of Tifton 85 Bermudagrass at Lins municipality-SP-Brasil

Silva, Aijânio Gomes de Brito
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/04/2013 PT
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O uso de efluente de estação de tratamento de esgoto (EETE) na agricultura irrigada pode ser uma estratégia alternativa de fornecimento de água e nutrientes para culturas agrícolas. Entretanto se realizado por longos períodos pode adicionar grandes quantidades de sódio ao solo o que poderia levar a degradação de suas propriedades e impacto em aspectos agronômicos de capim Tifton 85. Esse trabalho consistiu de dois objetivos: i) avaliar os efeitos da irrigação com efluente rico em sódio durante mais de oito anos em propriedades químicas e físico-hídricas de um Argissolo Vermelho. Para isso foram estabelecidos três tratamentos avaliados nas profundidades de 0,05-0,15 (P1), 0,25-0,35 (P2) e 0,70-0,80 m (P3): SI - cultivo de capim sem adubação e sem irrigação; A100 - cultivo irrigado com água de abastecimento sódica e adubado com 520,0 kg ha-1 ano-1 de nitrogênio; E66 - cultivo irrigado com EETE e adubado com 343,2 kg ha-1 ano-1 de nitrogênio. Foram determinados: pH do solo (em água e CaCl2), condutividade elétrica do extrato aquoso do solo (CE1:1), concentração de sódio (Na+), potássio (K+), cálcio (Ca2+), magnésio (Mg2+), alumínio (Al3+), carbono (C) e nitrogênio (N) do solo, com posterior cálculo de soma de bases (SB)...

Equivalences between refractive index and equilibrium water content of conventional and silicone hydrogel soft contact lenses from automated and manual refractometry

González-Méijome, José Manuel; López-Alemany, António; Lira, Madalena; Almeida, José B.; Oliveira, M. Elisabete; Parafita, Manuel A.
Fonte: Wiley InterScience Publicador: Wiley InterScience
Tipo: Artigo de Revista Científica
Publicado em /05/2006 ENG
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PURPOSE: The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. METHODS: Twelve HEMA-based hydrogels of different hydration and four siloxane-based polymers were assayed. A manual refractometer and a digital refractometer were used. Polynomial models obtained from the sucrose curves of equilibrium water content against refractive index and vice-versa were used either considering the whole range of sucrose concentrations (16-100% equilibrium water content) or a range confined to the equilibrium water content of current soft contact lenses ( approximately 20-80% equilibrium water content). RESULTS: Values of equilibrium water content measured with the Atago N-2E and those derived from the refractive index measurement with CLR 12-70 by the applications of sucrose-based models displayed a strong linear correlation (r(2) = 0.978). The same correlations were obtained when the models are applied to obtain refractive index values from the Atago N-2E and compared with those (values) given by the CLR 12-70 (r(2) = 0.978). No significantly different results are obtained between models derived from the whole range of the sucrose solution or the model limited to the normal range of soft contact lens hydration. CONCLUSIONS: Present results will have implications for future experimental and clinical research regarding normal hydration and dehydration experiments with hydrogel polymers...

Effect of water and citrate solubility on agronomic effectiveness of acidulated phosphates in three consecutive corn crops

Prochnow,L. I.; van Raij,B.; Kiehl,J. C.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2002 EN
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In the process of phosphate rock acidulation, several impure P compounds may be formed along with the desirable Ca and NH4 phosphates. Such compounds normally reduce the content of water-soluble P and thus the agronomic effectiveness of commercial fertilizers. In order to study this problem, a greenhouse experiment consisting of three consecutive corn crops was conducted in samples of a Red-Yellow Latosol (Typical Hapludox) in a completely randomized design (6 x 2 x 2), with four replicates. Six commercial fertilizers were added to 2 kg of soil at a rate of 70 mg kg-1 P, based on the content of soluble P in neutral ammonium citrate plus water (NAC + H2O) of the fertilizers. Fertilizer application occurred either in the original form or leached to remove the water-soluble fraction, either by mixing the fertilizer with the whole soil in the pots or with only 1 % of its volume. The corn plants were harvested 40 days after emergence to determine the shoot dry matter and accumulated P. For the first crop and localized application, the elimination of water-soluble P from the original fertilizers resulted in less bioavailable P for the plants. For the second and third crops, the effects of P source, leaching and application methods were not as evident as for the first...

OPTIMIZATION OF DEMULSIFIER FORMULATION FOR SEPARATION OF WATER FROM CRUDE OIL EMULSIONS

Hajivand,P.; Vaziri,A.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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Abstract In this study, various water-soluble and oil-soluble demulsifiers were selected for separation of water from crude oil emulsions and their productivity measured using the Bottle-test method at 70 °C and 10 ppm concentration. The best ones among 23 demulsifiers examined through the screening process were fatty alcohol ethoxylate, triethanol amine and urea from the water-soluble group and Basororol E2032, Basorol PDB 9935 and TOMAC from the oil-soluble category. Furthermore, the present study investigated the factors effective for demulsification such as temperature, concentration, pH, salinity and modifiers. It was found that the separation improves with increasing demulsifier concentration, increasing salt content, increasing temperature up to 80 °C, keeping the pH values between 5-9. Adding solvent modifiers proved unnecessary. Two formulations were prepared based on suggested optimal concentrations of demulsifier content by experimental design using Qualitec 4 and these proved to be highly effective in treating real and synthetic emulsions.

EFFECT OF NON-DARCY FLOW COEFFICIENT VARIATION DUE TO WATER VAPORIZATION ON WELL PRODUCTIVITY OF GAS CONDENSATE RESERVOIRS

Sheikhi,E.; Hashemi,A.; Kaffash,A.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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Abstract Well productivity of gas condensate reservoirs is highly affected by near-wellbore phenomena. Inertial force resulting from convective acceleration of fluid particles in the medium, as well as viscous force, determines the flow of gas through porous media at high velocity. Pressure drop builds up the molar content of water in gas by water vaporization in the near-wellbore region, which means a drop in connate water saturation. Given that the inertial force is a function of the non-Darcy coefficient, β, which itself depends upon connate water saturation, this can ultimately lessen the non-Darcy component of the pressure drop and therefore inertial forces, leading to improvement of well deliverability. Currently, no physically relevant model takes into account the non-Darcian flow coefficient variation due to this phenomenon. This paper utilizes a single-well compositional simulation to exhibit how water vaporization could compensate for the effect of inertia on well productivity of gas condensate reservoirs.

Nitrogen loads and concentrations in Florida streams ( FGS: Map series 75 )

Slack, Larry J; Goolsby, D. A. ( joint author ); Tucker, D. F; Tomberlin, J. A; Florida -- Bureau of Water Resources Management; Florida -- Bureau of Geology; Geological Survey (U.S.)
Fonte: Bureau of Geology ( Tallahassee ) Publicador: Bureau of Geology ( Tallahassee )
Tipo: cartographic Formato: 1 map : col. ; 41 x 51 cm.
Publicado em //1976 ENGLISH
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(Bibliography) Bibliography.; Also shows nitrogen data stations.; In upper margin: United States Department of the Interior, Geological Survey.; Includes text, 2 graphs, "A simplified diagram of the nitrogen cycle," and 3 tables of nitrogen load data.; (Funding) Map series (Florida. Bureau of Geology) ;; (Statement of Responsibility) by Larry J. Slack and Donald A. Goolsby ; prepared in cooperation with the Bureau of Water Resources Management, Florida Department of Environmental Regulation, and Bureau of Geology, Florida Department of Natural Resources ; graphics by D. F. Tucker and J. A. Tomberlin.

Hydrology of Lake Tarpon, near Tarpon Springs, Florida ( FGS: Map series 60 )

Hunn, James D., 1932-; Geological Survey (U.S.); Southwest Florida Water Management District (Fla.); Florida -- Bureau of Geology
Fonte: The Bureau ( Tallahassee ) Publicador: The Bureau ( Tallahassee )
Tipo: cartographic Formato: 1 map : col. ; 54 x 28 cm. on sheet 62 x 94 cm.
Publicado em //1974 ENGLISH
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(Bibliography) Bibliography.; Depths shown by contours (May 1972) and soundings.; Photomap (land area only).; "624, Photography May 5, 1972, by Kucera and Associates, Inc., Lakeland, Florida."; Includes text, satellite image of Lake Tarpon, 5 graphs, indexed table of "Chloride content of water samples taken April 25, 1972," and location map.; (Funding) Map series (Florida. Bureau of Geology) ;; (Statement of Responsibility) by J. D. Hunn ; prepared by United States Geological Survey in cooperation with the Southwest Florida Water Management District and the Bureau of Geology, Florida Department of Natural Resources.

Recharge areas of the Floridan aquifer in Seminole County and vicinity, Florida ( FGS: Map series 68 )

Tibbals, C. H; Geological Survey (U.S.); Florida -- Dept. of Natural Resources; Seminole County (Fla.) -- Commissioners; Florida -- Bureau of Geology
Fonte: Fla. Dept. of Natural Resources, Bureau of Geology ( Tallahassee ) Publicador: Fla. Dept. of Natural Resources, Bureau of Geology ( Tallahassee )
Tipo: cartographic Formato: 1 map : col. ; 58 x 72 cm.
Publicado em //1975 ENGLISH
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(Bibliography) Bibliography.; Also shows hydrologic data collection stations.; Also covers Orlando region.; Includes text, inset "Map of Seminole County showing dissolved solids content of water ...," 2 graphs, and location map.; (Funding) Map series (Florida. Bureau of Geology) ;; (Statement of Responsibility) by C. H. Tibbals ; prepared by United States Geological Survey in cooperation with Florida Department of Natural Resources and Seminole County Commissioners.

Hydrologic features of the Floridan Aquifer in Seminole County, Florida

Hoy, N. D; Teel, J. R; Florida -- Division of Geology; Geological Survey (U.S.)
Fonte: Florida Board of Conservation, Division of Geology ( Tallahassee Fla.?, Tallahassee Fla.? ) Publicador: Florida Board of Conservation, Division of Geology ( Tallahassee Fla.?, Tallahassee Fla.? )
Tipo: cartographic Formato: 1 map : col. ; 28 x 41 cm., on sheet 49 x 64 cm.
Publicado em //1963 ENGLISH
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In upper margin: January 1963.; In left upper margin: United States Department of the Interior, Geological Survey.; Includes 10 graphs and 2 geologic cross-sections.; Ancillary maps: Dissolved-solids content of the water -- Location of Seminole County and piezometric surface, 1961 -- Location of geologic sections -- Location of wells; (Statement of Responsibility) prepared by N.D. Hoy and J.R. Teel from Barraclough, 1962.

Effect of water stress during seed development on morphometric characteristics and dormancy of wild radish (Raphanus raphanistrum L.) seeds

Eslami, S.; Gill, G.; McDonald, G.
Fonte: Gorgan University of Agricultural Sciences and Natural Resources Publicador: Gorgan University of Agricultural Sciences and Natural Resources
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
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The effects of water stress on morphometric characteristics of wild radish seeds as well as the expression of its seed dormancy were investigated in a pot trial at Roseworthy, South Australia in 2005. This experiment was carried out in a completely randomised design with five water regimes (control, S4, S5, S6 and S8) and four replicates. The water stress was exerted by withholding irrigation and placing the pots under a rain shelter at different growth stages starting with the onset of flowering (S4) and ending with the completion of flowering (S8). Wild radish pods from all the treatments were collected fortnightly from November 11 to December 23, 2005 (four collection dates). Seed dormancy was tested with and without pod for all treatments in January and May 2005. All morphometric characteristics of pods including pod wall weight and seed weight were negatively affected by water stress. Pods sampled earlier had thicker pod walls and greater pod segment weight. The germinability of all treatments increased with pod removal. The dormancy level tended to be lower in later collected pods. This Study showed that expression of seed dormancy was influenced by water stress during reproductive development. Therefore, variability in spring rainfall could have a major influence on the level of dormancy in seeds of this weed species produced in different growing seasons.; S.V. Eslami...

EFFECT OF WATER CONTENT, TEMPERATURE AND AVERAGE DROPLET SIZE ON THE SETTLING VELOCITY OF WATER-IN-OIL EMULSIONS

Souza,W. J.; Santos,K. M. C.; Cruz,A. A.; Franceschi,E.; Dariva,C.; Santos,A. F.; Santana,C. C.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
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AbstractWater-in-oil (W/O) emulsions are complex mixtures generally found in crude oil production in reservoirs and processing equipment. Sedimentation studies of water-oil emulsions enable the analysis of the fluid dynamic behavior concerning separation of this system composed of two immiscible liquids. Gravitational settling was evaluated in this article for a model emulsion system consisting of water and a Brazilian crude oil diluted in a clear mineral oil as organic phase. The effects of water content and temperature were considered in the study of sedimentation velocity of water-oil emulsions. Water contents between 10% and 50 % and temperatures of 25, 40 and 60 ºC were evaluated, and a Richardson-Zaki type correlation was obtained to calculate settling velocities as a function of the process variables investigated. Water contents and average droplet sizes were monitored at different levels in the settling equipment, thus enabling identification of the effect of these variables on the phenomena of sedimentation and coalescence of the emulsions studied. The results showed that the emulsion stability during sedimentation was governed by the emulsion water content, which yielded high settling velocities at low water contents, even when very small droplets were present. A quantitative analysis of the combined effects of drop size and droplet concentration supports the conclusion that a stronger effect is produced by the higher concentration of particles...

Environmental assessment and biomonitoring of the Twelve Mile Creek watershed, Niagara Peninsula, Ontario

Campbell, Ian T.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
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In light of the heavy reliance of the people of the Niagara Peninsula on the T\\'elve Mile Creek (TMC) watershed for recreational activities and for municipal and industrial uses ( e.g., drinking water, shipping and discharge of effluents), it was deemed prudent to assess the envirol1tnental health of the system by analysing the sediments total and exchangeable metal, and TPH contents. The MOEE has set guidelines with limits for the protection and management of aquatic sediments, and the sediments from the headwaters of the TMC have total metal and TPH (subset of O&G) contents well below the lower provincial limits. Areas of environmental concern where total metal contents in sediments, either individually or collectively, exceed the guideline, are the south side of Lake Gibson, the Old WeIland Canal, a segment of TMC just south of the QEW and Martindale Pond. The total metal content of sediments does not in all instances identify areas of biological concern. Instead, it has been found that the exchangeable metal fraction of sediments is a better indicator of metal availability and thus potential accumulation in organisms. In some instances, the exchangeable metal fraction agrees with the total metal fraction defining areas of environmental concern...

Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

Gomes,Mara de Menezes de Assis; Lagôa,Ana Maria Magalhães Andrade; Medina,Camilo Lázaro; Machado,Eduardo Caruso; Machado,Marcos Antônio
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 EN
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Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

Canopy water content estimates with AVIRIS imagery and MODIS reflectance products

Cheng, Yen-Ben; Riaño, D.; Zarco-Tejada, Pablo J.; Ustin, S. L.
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Comunicación de congreso Formato: 4085 bytes; image/gif
ENG
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En: Remote Sensing and Modeling of Ecosystems for Sustainability III . -- Proceedings of the International Society for Optical Engineering (SPIE), 14 August 2006 , San Diego, California, USA; We assessed the capability of AVIRIS and MODIS to estimate canopy water content. Hyperspectral water retrievals with AVIRIS data, EWT, were compared to in situ leaf water content and LAI measurements at a semi-arid site in southeastern Arizona. Retrievals of EWT showed good correlation with field canopy water content measurements. Statistical analysis also suggested that EWT was significant among seven different vegetation communities. Four MODIS indexes derived from band ratios using the reflectance product and were compared to retrievals of EWT with AVIRIS at both the semi-arid site and a temperate conifer forest. Good statistical agreements were found between AVIRIS EWT and all four MODIS indexes at the semi-arid site in savanna shrub communities. Slightly poorer correlations were found at the forest site where water indexes had better correlation to AVIRIS EWT than vegetation indexes. Temporal patterns of the four indexes in all semi-arid vegetation communities except creosote bush and agriculture show distinct seasonal variation and responded to precipitation at the savanna site. Three years of net ecosystem exchange (NEE) data from eddy covariance measurements at the forest site were compared to the time series of MODIS indexes. MODIS water indexes showed similar seasonal patterns to NEE that were strongest during the period of net carbon sequestration. In contrast...

Soil: water relationships in the Weatherley catchment, South Africa

van Huyssteen,CW; Zere,TB; Hensley,M
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
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Soil water content is influenced by soil and terrain factors, but studies on the predictive value of diagnostic horizon type for the degree and duration of wetness seem to be lacking. The aim of this paper is therefore to describe selected hydropedological soil-water relationships for important soils and diagnostic horizons in the Weatherley catchment. Daily soil water content was determined for 3 horizons in 28 profiles of the Weatherley catchment. These data were used to calculate annual duration of water saturation above 0.7 of porosity (AD ), which was correlated against other soil properties. Significant correlations (α = 0.05) were obtained between average degree of water saturation per profile and slope (R² = 0.24), coarse sand content (R² = 0.22), medium sand content (R² = 0.23), fine silt content (R² = 0.19), and clay content (R² = 0.38). AD per diagnostic horizon ranged from 21 to 29 d•yr-1 for the red apedal B, yellow brown apedal B, and neocutanic B horizons; 103 d•yr-1 for the orthic A horizons; and from 239 to 357 d•yr-1 for the soft plinthic B, unspecified material with signs of wetness, E, and G horizons. A regression equation to predict AD from diagnostic horizon type (DH), clay to sand ratio (Cl:Sa), and underlying horizon type (DH ) gave: AD = -26.31 + 41.64 ln(Cl:Sa) + 35.43 DH + 13.73 DH (R² = 0.78).Results presented here emphasise the value of soil classification in the prediction of duration of water saturation.