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Intra- and extracellular osmotic regulation in the hololimnetic Caridea and Anomura: a phylogenetic perspective on the conquest of fresh water by the decapod Crustacea

FARIA, Samuel Coelho de; AUGUSTO, Alessandra Silva; MCNAMARA, John Campbell
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.29%
We investigate extra- and intracellular osmoregulatory capability in two species of hololimnetic Caridea and Anomura: Macrobrachium brasiliense, a palaemonid shrimp, and Aegla franca, an aeglid anomuran, both restricted to continental waters. We also appraise the sharing of physiological characteristics by the hololimnetic Decapoda, and their origins and role in the conquest of fresh water. Both species survive salinity exposure well. While overall hyperosmoregulatory capability is weak in A. franca and moderate in M. brasiliense, both species strongly hyporegulate hemolymph [Cl(-)] but not osmolality. Muscle total free amino acids (FAA) increase slowly but markedly in response to the rapid rise in hemolymph osmolality consequent to hyperosmotic challenge: 3.5-fold in A. franca and 1.9-fold in M. brasiliense. Glycine, taurine, arginine, alanine and proline constitute a parts per thousand 85% of muscle FAA pools in fresh water; taurine, arginine, alanine each contribute a parts per thousand 22% in A. franca, while glycine predominates (70%) in M. brasiliense. These FAA also show the greatest increases on salinity challenge. Muscle FAA titers correlate strongly (R = 0.82) with hemolymph osmolalities across the main decapod sub/infraorders...

Paper-based diffusive gradients in thin films technique coupled to energy dispersive X-ray fluorescence spectrometry for the determination of labile Mn, Co, Ni, Cu, Zn and Pb in river water

de Almeida, Eduardo; do Nascimento Filho, Virgilio Franco; Menegario, Amauri Antonio
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.17%
The diffusive gradients in thin films (DGT) technique has shown enormous potential for labile metal monitoring in fresh water due to the preconcentration, time-integrated, matrix interference removal and speciation analytical features. In this work, the coupling of energy dispersive X-ray fluorescence (EDXRF) with paper-based DGT devices was evaluated for the direct determination of Mn, Co. Ni, Cu, Zn and Pb in fresh water. The DGT samplers were assembled with cellulose (Whatman 3 MM chromatography paper) as the diffusion layer and a cellulose phosphate ion exchange membrane (Whatman P 81 paper) as the binding agent. The diffusion coefficients of the analytes on 3 MM chromatography paper were calculated by deploying the DGT samplers in synthetic solutions containing 500 mu g L-1 of Mn. Co, Ni, Cu, Zn and Pb (4 L at pH 5.5 and ionic strength at 0.05 mol L-1). After retrieval, the DGT units were disassembled and the P81 papers were dried and analysed by EDXRF directly. The 3 MM chromatographic paper diffusion coefficients of the analytes ranged from 1.67 to 1.87 x 10(-6) cm(2) s(-1). The metal retention and phosphate group homogeneities on the P81 membrane was studied by a spot analysis with a diameter of 1 mm. The proposed approach (DGT-EDXRF coupling) was applied to determine the analytes at five sampling sites (48 h in situ deployment) on the Piracicaba river basin...

Intra- and extracellular osmotic regulation in the hololimnetic Caridea and Anomura: a phylogenetic perspective on the conquest of fresh water by the decapod Crustacea

de Faria, Samuel Coelho; Augusto, Alessandra da Silva; McNamara, John Campbell
Fonte: Springer Heidelberg Publicador: Springer Heidelberg
Tipo: Artigo de Revista Científica Formato: 175-186
ENG
Relevância na Pesquisa
66.29%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 07/04870-9; We investigate extra- and intracellular osmoregulatory capability in two species of hololimnetic Caridea and Anomura: Macrobrachium brasiliense, a palaemonid shrimp, and Aegla franca, an aeglid anomuran, both restricted to continental waters. We also appraise the sharing of physiological characteristics by the hololimnetic Decapoda, and their origins and role in the conquest of fresh water. Both species survive salinity exposure well. While overall hyperosmoregulatory capability is weak in A. franca and moderate in M. brasiliense, both species strongly hyporegulate hemolymph [Cl-] but not osmolality. Muscle total free amino acids (FAA) increase slowly but markedly in response to the rapid rise in hemolymph osmolality consequent to hyperosmotic challenge: 3.5-fold in A. franca and 1.9-fold in M. brasiliense. Glycine, taurine, arginine, alanine and proline constitute a parts per thousand 85% of muscle FAA pools in fresh water; taurine, arginine, alanine each contribute a parts per thousand 22% in A. franca, while glycine predominates (70%) in M. brasiliense. These FAA also show the greatest increases on salinity challenge. Muscle FAA titers correlate strongly (R = 0.82) with hemolymph osmolalities across the main decapod sub/infraorders...

SEROTYPES AND VIRULENCE OF SALMONELLA SP ISOLATED FROM FRESH-WATER

VALENTINI, SR; Leite, CQF
Fonte: Soc Brasileira Microbiologia Publicador: Soc Brasileira Microbiologia
Tipo: Artigo de Revista Científica Formato: 37-40
ENG
Relevância na Pesquisa
66.14%
Twenty six Salmonella isolates of different serotypes were found in samples of fresh water. All 26 strains were checked for the presence of plasmids. Plasmids were found in eleven isolates. Four of the plasmid-containing strains and two of the plasmid-free strains were tested for invasiveness in mice. At least in the case of S. typhimurium, it seems reasonable to link virulence with plasmid harbouring.

Paper-based diffusive gradients in thin films technique coupled to energy dispersive X-ray fluorescence spectrometry for the determination of labile Mn, Co, Ni, Cu, Zn and Pb in river water

de Almeida, Eduardo; do Nascimento Filho, Virgilio Franco; Menegario, Amauri Antonio
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 70-74
ENG
Relevância na Pesquisa
56.17%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The diffusive gradients in thin films (DGT) technique has shown enormous potential for labile metal monitoring in fresh water due to the preconcentration, time-integrated, matrix interference removal and speciation analytical features. In this work, the coupling of energy dispersive X-ray fluorescence (EDXRF) with paper-based DGT devices was evaluated for the direct determination of Mn, Co. Ni, Cu, Zn and Pb in fresh water. The DGT samplers were assembled with cellulose (Whatman 3 MM chromatography paper) as the diffusion layer and a cellulose phosphate ion exchange membrane (Whatman P 81 paper) as the binding agent. The diffusion coefficients of the analytes on 3 MM chromatography paper were calculated by deploying the DGT samplers in synthetic solutions containing 500 mu g L-1 of Mn. Co, Ni, Cu, Zn and Pb (4 L at pH 5.5 and ionic strength at 0.05 mol L-1). After retrieval, the DGT units were disassembled and the P81 papers were dried and analysed by EDXRF directly. The 3 MM chromatographic paper diffusion coefficients of the analytes ranged from 1.67 to 1.87 x 10(-6) cm(2) s(-1). The metal retention and phosphate group homogeneities on the P81 membrane was studied by a spot analysis with a diameter of 1 mm. The proposed approach (DGT-EDXRF coupling) was applied to determine the analytes at five sampling sites (48 h in situ deployment) on the Piracicaba river basin...

Avaliação da ocorrência de oocistos de Cryptosporidium spp. e cistos de Giardia spp. em amostras de água superficial e da interface sedimento-água do Rio Capivari, na cidade de Campinas, São Paulo, Brasil; Evalution of the occurrence of the Cryptosporidium spp. oocysts and Giardia spp. cysts fresh water samples and of the sediment-water interface from Capivari River in the city of Campinas, São Paulo, Brazil

Antônio de Lima Barros Junior
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/08/2011 PT
Relevância na Pesquisa
56.18%
Os protozoários patogênicos gastrointestinais, Cryptosporidium spp. e Giardia spp. estão amplamente presentes em ambientes aquáticos e suas formas infectantes (oocistos e cistos), são resistentes às condições ambientais (temperatura e radiação solar) e ao processo de desinfecção da água (principalmente à cloração). Inúmeros surtos de gastroenterite foram causados por estes organismos devido à veiculação hídrica, sendo que estes protozoários patogênicos tornaram-se uma preocupação constante para os sistemas produtores de água. Os objetivos desta pesquisa foram: verificar a ocorrência de cistos de Giardia spp. e oocistos de Cryptosporidium spp. em amostras de água do rio Capivari em dois pontos, identificados como CAP1 (localizado na estação de tratamento de água ETA Capivari) e CAP2 (à montante da mesma estação), avaliar a interface sedimento-água no ponto CAP1, com periodicidade mensal de agosto 2009 à Janeiro 2011, avaliar a qualidade da água mediante análise microbiológica e físico-química deste manancial. Para os ensaios parasitológicos, foi empregada a técnica de filtração em membrana de acordo com Franco et al., (2001) e visualização mediante reação de imunofluorescência direta (RID) com anticorpos monoclonais comerciais para visualização de cistos e oocistos; para ensaios microbiológicos visando a detecção de coliformes termotolerantes...

Field sampling system for determination of cadmium and nickel in fresh water by flame atomic absorption spectrometry

Santos,Walter N. L. dos; Santos,Carla M. dos; Ferreira,Sérgio L. C.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2005 EN
Relevância na Pesquisa
66.23%
A system containing Amberlite XAD - 2 (styrene-divinylbenzene copolymers) loaded with 2-(2thiazolylazo)-5-dimethylaminophenol (TAM) reagent is proposed for field sampling, preconcentration and determination of cadmium (II) and nickel (II) ions in fresh water using flame atomic absorption spectrometry (FAAS). The optimisation process was univariate and the followings parameters were studied: pH effect, effect of sample flow rate, eluent concentration and flow rate, effect of other ions, precision and accuracy as recovery tests. In the sampling step, metal ions are retained in a minicolumn as TAM complexes. The sample is pumped at 3.0 mL min-1 with on-line filtration using a 0.45 µm filter. Afterwards, the minicolumn is incorporated in a flow-injection system and the metal ions eluted with a solution of 1.0 mol L-1 hydrochloric acid into the nebuliser-burner system of the spectrometer. For nickel, the limits of detection (LOD) and quantification (LOQ) were 12 and 39 ng L -1, respectively. The precision expressed as relative standard deviation (RSD) for ten independent determinations was 5.5% and 7.0% for nickel concentrations of 10 and 1.0 µg L-1, respectively. The experimental preconcentration factor, calculated as the ratio of the slopes of the calibration curves obtained by the present procedure and manual direct aspiration was 637 for a sample volume of 150 mL. For cadmium...

STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER

Allison, J. B.; Cole, William H.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 20/07/1934 EN
Relevância na Pesquisa
46.41%
1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water. 2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water. 3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value. 4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water. 5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However...

Methicillin-resistant Staphylococcus aureus from Northwest Marine and Fresh Water Recreational Beaches

Levin-Edens, Emily; Soge, Olusegun O.; No, David; Stiffarm, Amy; Meschke, J. Scott; Roberts, Marilyn C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.35%
The aim of the study was to determine the spatial distribution of methicillin-resistant Staphylococcus aureus [MRSA] at two marine and one fresh water recreational beaches in the Seattle area. Fifty-six marine water, 144 fresh water, and 96 sand samples were collected from June through August 2010. Isolates were biochemically verified as MRSA. Staphylococcal cassette chromosome mec (SCCmec) typing, multilocus sequence typing [MLST], pulse field gel electrophoresis [PFGE] and the presence of other antibiotic resistance genes were determined. Twenty-two fresh water [15.3%; n = 144], one dry sand [1.9%; n = 53], six wet sand [14%; n = 43], and 2 marine water samples [3.6%; n = 56] were MRSA positive. Of the 27 fresh water stream sites sampled multiple times, 37% of the sites were positive for MRSA and/or S. aureus ≥ 2 times. Twenty-one (67.7%) of 31 MRSA were SCCmec type IV, fifteen (48.4%) of the isolates had MLST types not previously associated with humans, and 29 (93.5%) of the isolates carried other antibiotic resistance genes. This study is the first to report and characterize repeated MRSA positive samples from fresh water drainages and creeks surrounding popular recreational beaches.

Biological Differences between Brackish and Fresh Water-Derived Aedes aegypti from Two Locations in the Jaffna Peninsula of Sri Lanka and the Implications for Arboviral Disease Transmission

Ramasamy, Ranjan; Jude, Pavilupillai J.; Veluppillai, Thabothiny; Eswaramohan, Thampoe; Surendran, Sinnathamby N.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 29/08/2014 EN
Relevância na Pesquisa
46.47%
The mainly fresh water arboviral vector Aedes aegypti L. (Diptera: Culicidae) can also undergo pre-imaginal development in brackish water of up to 15 ppt (parts per thousand) salt in coastal areas. We investigated differences in salinity tolerance, egg laying preference, egg hatching and larval development times and resistance to common insecticides in Ae. aegypti collected from brackish and fresh water habitats in Jaffna, Sri Lanka. Brackish water-derived Ae. aegypti were more tolerant of salinity than fresh water-derived Ae. aegypti and this difference was only partly reduced after their transfer to fresh water for up to five generations. Brackish water-derived Ae. aegypti did not significantly discriminate between 10 ppt salt brackish water and fresh water for oviposition, while fresh water-derived Ae. aegypti preferred fresh water. The hatching of eggs from both brackish and fresh water-derived Ae. aegypti was less efficient and the time taken for larvae to develop into pupae was prolonged in 10 ppt salt brackish water. Ae. aegypti isolated from coastal brackish water were less resistant to the organophosphate insecticide malathion than inland fresh water Ae. aegypti. Brackish and fresh water-derived Ae. aegypti however were able to mate and produce viable offspring in the laboratory. The results suggest that development in brackish water is characterised by pertinent biological changes...

Thickness of the potable-water zone in the Floridan aquifer ( FGS: Map series 74 )

Causey, Lawson V., 1917-; Leve, Gilbert W ( Gilbert Warren ), 1928-; Geological Survey (U.S.); Florida -- Bureau of Water Resources Management; 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. ; 41 x 51 cm.
Publicado em //1976 ENGLISH
Relevância na Pesquisa
56.26%
Includes text and 2 insets: "Depth to top of the Floridan Aquifer in Florida," and "Potentiometric surface, Floridan Aquifer."; (Funding) Map series (Florida. Bureau of Geology) ;; (Statement of Responsibility) by L. V. Causey and G. W. Leve ; prepared by United States Geological Survey in cooperation with Florida Department of Environmental Regulation, Bureau of Water Resources Management.

Proyecto de viabilidad de una empresa dedicada al suministro y transporte masivo agua dulce por vía marítima. Oceanica Water; Feasibility study of a company project dedicated to the massive supply and transport of fresh water by sea. Oceanica Water

Soler Oroz, Luis
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Trabalho de Conclusão de Curso
SPA
Relevância na Pesquisa
56.11%
Es un hecho indiscutible que el calentamiento global está desde hace algunos años, poniendo en riesgo la disponibilidad de uno de nuestros recursos naturales más preciados, el agua dulce. De todos es conocido que el cinturón mediterráneo es una de las zonas más críticas con respecto a los periodos cíclicos de escasez de agua que de forma periódica castiga las poblaciones costeras insulares y peninsulares. De cualquier forma el movimiento de masas de agua en grandes cantidades podría tener no solo efectos políticos y de opinión pública en contra graves, sino también efectos ambientales catastróficos. La empresa que nos ocupa pretende ocupar un nicho de mercado completamente nuevo en este sentido, primero porque no tiene competencia en Europa hasta el momento con ninguna empresa que, como las Americanas, comercialice exclusivamente agua, sino porque en segundo lugar y lo que es más importante, porque Oceánica aporta fuentes alternativas de agua dulce “artificial” como es la procedente de las potentes desalinizadoras instaladas en el litoral Mediterráneo con quienes tiene ya un acuerdo marco de colaboración a través de la empresa que las gestiona, para comercializar el agua excedentaria que estas desalinizadoras producen. Este “inevitable” excedente que supone una enorme cantidad de agua potable...

Radium Isotopes as Tracers of Groundwater-Surface Water Interactions in Inland Environments

Raanan Kiperwas, Hadas
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2011
Relevância na Pesquisa
46.39%

Groundwater has an important role in forging the composition of surface water, supplying nutrients crucial for the development of balanced ecosystems and potentially introducing contaminants into otherwise pristine surface water. Due to water-rock interactions radium (Ra) in groundwater is typically much more abundant than in surface water. In saline environments Ra is soluble and is considered a conservative tracer (apart for radioactive decay) for Ra-rich groundwater seepage. Hence in coastal environments, where mostly fresh groundwater seep into saline surface water, Ra has been the prominent tracer for tracking and modeling groundwater seepage over more than three decades. However, due to its reactivity and non-conservative behavior, Ra is rarely used for tracing groundwater seepage into fresh or hypersaline surface water; in freshwater, Ra is lost mostly through adsorption onto sediments and suspended particles; in hypersaline environments Ra can be removed through co-precipitation, most notably with sulfate salts.

This work examines the use of Ra as a tracer for groundwater seepage into freshwater lakes and rivers and into hypersaline lakes. The study examines groundwater-surface water interactions in four different environments and salinity ranges that include (1) saline groundwater discharge into a fresh water lake (the Sea of Galilee...

Wells For The Observation Of Chloride And Water Levels In Aquifers That Cross The Chesapeake And Delaware Canal

Rasmussen, W.C.; Groot, J.J.; Beamer, N.H.
Fonte: Newark, DE: Delaware Geological Survey, University of Delaware Publicador: Newark, DE: Delaware Geological Survey, University of Delaware
Tipo: Relatório
EN_US
Relevância na Pesquisa
56.24%
Three test wells were drilled near the banks of the Chesapeake and Delaware Canal, in aquifers formed by sand beds in two geologic units, the nonmarine Cretaceous sediments and the Magothy formation, which crop out along the sides and across the bottom of the canal. The canal carries tidal flow from the Delaware River to and from Chesapeake Bay. The purpose of the wells was to determine whether salt water from the canal has entered the water-bearing beds of these formations, and to determine the head of water in them. It was found that the sands contain fresh water, uncontaminated, and that apparently there was discharge of fresh water from the aquifers to the canal under low head, at least from the winter of late 1955 through early autumn 1957.; U.S. Geological Survey and U.S. Army Corps of Engineers

Results Of The Coastal Sussex County, Delaware Ground-Water Quality Survey

Andres, A.S.
Fonte: Newark, DE: Delaware Geological Survey, University of Delaware Publicador: Newark, DE: Delaware Geological Survey, University of Delaware
Tipo: Relatório
EN_US
Relevância na Pesquisa
56.11%
The results of this investigation of the Columbia aquifer in coastal Sussex County, Delaware, provide some of the data necessary to evaluate the condition of the area's primary source of fresh water. Chemical analyses of water samples from domestic, agricultural, public, and monitoring wells document the effects of past and present land use practices. Groundwater flow paths and flow systems are inferred from flow-net analysis, ground-water chemistry, and isotopic composition.

Fresh-water lenses and practical limitations of three-dimensional simulation

Ghassemi, F; Alam, K; Howard, K
Fonte: Verlag-Heinz Heise, GmbH & Co KG Publicador: Verlag-Heinz Heise, GmbH & Co KG
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.17%
Fresh-water lenses are the major sources of water supply in many atoll islands in the Pacific and Indian Oceans, particularly in dry seasons. Several two- and three-dimensional models are currently available for the simulation of atoll-island aquifers; however, 2D models cannot include 3D spatial variability of material properties, they must simplify the boundary conditions, and they cannot correctly simulate pumping wells. In an attempt to overcome these difficulties, a 3D model, SALTFLOW, was adopted for the simulation of Home Island in the Indian Ocean. This exercise required a discretisation on the order of a few metres and time steps of a few hours requiring significantly high CPU times. High CPU demand proved to be a difficult challenge but cannot be considered a serious practical limitation with today's advanced computers. The exhaustive data demands of the model (e.g., 3D distributions of hydraulic conductivity, porosity, dispersivities, and spatial and temporal variations of recharge and extraction rates) proved to be more problematical. Although the Home Island data set is unusually comprehensive by any standards, nonetheless the quality and quantity of the available data proved inadequate to meet the calibration needs of a highly karstic aquifer system. The Home Island modeling demonstrates the practical limitations of 3D models. It raises the concern that our ability to develop computer codes capable of simulating complex systems now exceeds our ability to supply the input data necessary for reliable calibration. Finally...

Process simulation for water consumption minimization in pulp mill

Dionísio De Oliveira,K.; Cardoso,M.; Nicolato,R.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
56.14%
Reducing the use of fresh water can lead to energy savings when this is properly planned and executed. Chemical process simulation has proven to be an effective tool for performing a global analysis of water systems to identify routes for maximizing the process efficiency concerning to water recovery. System closure has been introduces in pulp mills resulting in simultaneous buildup of non-process elements (NPEs). This buildup generates operational problems in the bleach plant, the biggest consuming stage of water. This paper describes how to use computer simulation tools to carry out a global analysis of a bleach mill plant in Brazil, using WinGEMS and CADSIM simulators, and the NICA-Donnan Model to predict NPE (Mn2+, Fe3+, Mg2+, Ca2+) distribution. Results obtained from simulation in this paper show which changes in the Kraft pulp process in order to implement water savings should be associated to new advanced technologies. The simulated value results for the NICA-Donnan model have been satisfactorily compared with the measurement value. The model made a good description of NPE behavior, and might assist the pulp mill in operating problems caused by the buildup of those elements.

Cell aggregation: a mechanism of pathogenic Leptospira to survive in fresh water

Trueba,Gabriel; Zapata,Sonia; Madrid,Kleber; Cullen,Paul; Haake,David
Fonte: International Microbiology Publicador: International Microbiology
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/03/2004 ENG
Relevância na Pesquisa
56.11%
Transmission of leptospirosis is facilitated by the survival of pathogenic leptospires in moist environments outside their mammalian host. In the present study, the survival mechanisms of Leptospira interrogans serovar Canicola in aqueous conditions and lack of nutrients were investigated. In distilled water, leptospires were able to remain motile for 110 days (pH 7.2). However, when incubated in a semi-solid medium composed of distilled water and 0.5% purified agarose (pH 7.2), they survived 347 days. In this viscous environment, aggregates of live spirochetes were observed. Neither antibiotics (e.g. tetracycline and ampicillin) nor nutrients inhibited leptospiral aggregation. Immunoblot analysis suggested that cells incubated in water down-regulate the expression of LipL31, an inner-membrane protein, but retain expression of other membrane proteins. These studies provide insights into the mechanisms by which pathogenic Leptospira survives for prolonged periods of time in natural aqueous environments, a key stage in the leptospiral lifecycle.

Water footprint of growing vegetables in selected smallholder irrigation schemes in South Africa

Nyambo,Patrick; Wakindiki,Isaiah IC
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2015 EN
Relevância na Pesquisa
56.03%
Crop water footprint (WF) is the volume of fresh water used to produce a certain crop in all the steps in the production line. The CROPWAT model was used to calculate crop evapotranspiration, differentiating green and blue water in Zanyokwe (ZIS), Thabina (TIS) and Tugela Ferry (TFIS) Irrigation Schemes. Green beans had the highest water footprint in all three irrigation schemes with 3 535.7 m³/t in TIS, 2 753 m³/t in TFIS and 2 407.6 m³/t in ZIS. Cabbage had the lowest water footprint. The highest water footprint for growing cabbage was 254.5 m³/t in TFIS, followed by 223.1 m³/t in TIS, and the lowest was 217.8 m³/t in ZIS. Green WF represented the highest percentage of water use at ZIS (50.5%), followed by blue water at 26.5% while grey water constituted 22.9%. At TFIS blue, green and grey water use was 23.1%, 56.7% and 20.2%, respectively. The differences observed in the WF of different crops and different schemes were attributed to the differences in weather and environmental characteristics. Green beans had the highest grey water footprint, i.e., 373 m³/t and the lowest was cabbage with 37 m³/t. Potato, spinach and tomatoes had footprints of 156 m³/t, 214 m³/t and 132 m³/t, respectively. For future research it is necessary to consider the possibility and trade-offs of shifting production of each crop to the places where it is most efficient...

Salinity of irrigation water in the Philippi farming area of the Cape Flats, Cape Town, South Africa

Aza-Gnandji,CD Ruben; Yongxin,Xu; Raitt,Lincoln; Levy,Jonathan
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
Relevância na Pesquisa
56.02%
This paper explores the nature, source and spatial variation of the salinity of water used for irrigation in a coastal urban farming area in Cape Town, South Africa, where water from the Cape Flats aquifer is drawn into storage ponds and used for crop irrigation. Water samples were collected in summer and winter from selected sites across the study area and were analysed for salinity as well as for concentrations of major and minor ions. Each site consists of one borehole and one pond. Isotope analysis was done for the summer samples so as to assess effects of evaporation on water quality and salinity. Descriptive statistics were used to compare the variation in range of concentration of specific ions with the recommended ranges set by the South African Department of Water Affairs and Forestry (DWAF) and the Food and Agriculture Organisation (FAO). Geographical information system (GIS) analysis was used to describe the spatial distribution of salinity across the study area, and hydro-geochemical analysis was used to assess the possibility of seawater intrusion into the aquifer system and to characterise groundwater in the study area. The results of the research showed that the concentrations of chloride, nitrate, potassium and sodium exceeded the target maximum limit according to DWAF and FAO guidelines. Groundwater and pond water were also observed to be brackish in most parts of the research area in terms of total dissolved salts content...