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William Alves

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Papers by William Alves

Research paper thumbnail of The frequency of schistosomal ovideposition in the heart

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1959

  1. Portions of the hearts of 30 subjects found to have vesical schistosomiasis at autopsy were ex... more 1) Portions of the hearts of 30 subjects found to have vesical schistosomiasis at autopsy were examined for the presence of ova in the auricles and ventricles.2) In none were ova discovered.3) Although schistosomal myocarditis may occur, it is a rare clinical myopathy, and the diagnosis in an endemic area cannot be established during life.

Research paper thumbnail of Determining Soil Salinity from Soil and Soil-Paste Electrical Conductivities: Sensitivity Analysis of Models

Soil Science Society of America Journal, 1989

Research paper thumbnail of Soil Electrical Conductivity and Soil Salinity: New Formulations and Calibrations

Soil Science Society of America Journal, 1989

A new model describing the relation between bulk soil electrical conductivity (ECa), volumetric c... more A new model describing the relation between bulk soil electrical conductivity (ECa), volumetric content (thetaw) and electrical conductivity of soil water (ECw) is given along with supporting evidence for its validity. The new model distinguishes between the water and salt present ...

Research paper thumbnail of New Calibrations for Determining Soil Electrical Conductivity—Depth Relations from Electromagnetic Measurements

Soil Science Society of America Journal, 1989

Research paper thumbnail of Estimating Soil Salinity from Saturated Soil-Paste Electrical Conductivity

Soil Science Society of America Journal, 1989

A method is presented for estimating the electrical conductivity of the saturated soil-paste extr... more A method is presented for estimating the electrical conductivity of the saturated soil-paste extract (EC,) from measurement of the electrical conductivity of the saturated soil-paste (EC,) and estimated saturated soil-paste water content (SP), for purposes of soil salinity appraisal. The method is suitable for both field and laboratory applications. Empirical relations are provided to estimate values of several parameters required for the method. The appropriateness of the method was tested using, two groups of soil samples, one of which varied widely in geographical sources and parent materials, in addition to texture and salinity. The method estimated the soil salinities very accurately (r' > 0.9; slope = 1.0; intercept z 0.0).

Research paper thumbnail of Determining Soil Salinity from Soil and Soil-Paste Electrical Conductivities: Sensitivity Analysis of Models

Soil Science Society of America Journal, 1989

Research paper thumbnail of Assessing irrigation/drainage/salinity management using spatially referenced salinity measurements

Agricultural Water Management, 1997

A unique technology-package for measuring the spatial distributions of salinity in irrigated soil... more A unique technology-package for measuring the spatial distributions of salinity in irrigated soils and fields and for evaluating the appropriateness of some related irrigation-, drainage- and salinity control-management practices is described. This assessment technology is based on the use of: (1) geophysical-instrumental systems for intensively measuring bulk soil electrical conductivity and associated spatial coordinates; (2) statistical algorithms for site selection and salinity calibration; and (3) algorithms for data analysis and graphical display to facilitate interpretation. Results are presented to demonstrate some of the utility of the technology. Additionally, examples are given which show that much of the apparent chaos observed in the spatial pattern of soil salinity in irrigated fields is man-induced and related to such management practices as irrigation, drainage, and tillage.

Research paper thumbnail of Determining Soil Salinity from Soil Electrical Conductivity using Different Models and Estimates

Soil Science Society of America Journal, 1990

... Title Determining soil salinity from soil electrical conductivity using different models and ... more ... Title Determining soil salinity from soil electrical conductivity using different models and estimates. Authors Rhoades, JD; Shouse, PJ; Alves, WJ; Manteghi, NA; Lesch, SM JournalSoil Science Society of America Journal 1990 Vol. 54 No. 1 pp. ...

Research paper thumbnail of Locating Sampling Sites for Salinity Mapping

Soil Science Society of America Journal, 1990

Research paper thumbnail of The frequency of schistosomal ovideposition in the heart

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1959

  1. Portions of the hearts of 30 subjects found to have vesical schistosomiasis at autopsy were ex... more 1) Portions of the hearts of 30 subjects found to have vesical schistosomiasis at autopsy were examined for the presence of ova in the auricles and ventricles.2) In none were ova discovered.3) Although schistosomal myocarditis may occur, it is a rare clinical myopathy, and the diagnosis in an endemic area cannot be established during life.

Research paper thumbnail of Determining Soil Salinity from Soil and Soil-Paste Electrical Conductivities: Sensitivity Analysis of Models

Soil Science Society of America Journal, 1989

Research paper thumbnail of Soil Electrical Conductivity and Soil Salinity: New Formulations and Calibrations

Soil Science Society of America Journal, 1989

A new model describing the relation between bulk soil electrical conductivity (ECa), volumetric c... more A new model describing the relation between bulk soil electrical conductivity (ECa), volumetric content (thetaw) and electrical conductivity of soil water (ECw) is given along with supporting evidence for its validity. The new model distinguishes between the water and salt present ...

Research paper thumbnail of New Calibrations for Determining Soil Electrical Conductivity—Depth Relations from Electromagnetic Measurements

Soil Science Society of America Journal, 1989

Research paper thumbnail of Estimating Soil Salinity from Saturated Soil-Paste Electrical Conductivity

Soil Science Society of America Journal, 1989

A method is presented for estimating the electrical conductivity of the saturated soil-paste extr... more A method is presented for estimating the electrical conductivity of the saturated soil-paste extract (EC,) from measurement of the electrical conductivity of the saturated soil-paste (EC,) and estimated saturated soil-paste water content (SP), for purposes of soil salinity appraisal. The method is suitable for both field and laboratory applications. Empirical relations are provided to estimate values of several parameters required for the method. The appropriateness of the method was tested using, two groups of soil samples, one of which varied widely in geographical sources and parent materials, in addition to texture and salinity. The method estimated the soil salinities very accurately (r' > 0.9; slope = 1.0; intercept z 0.0).

Research paper thumbnail of Determining Soil Salinity from Soil and Soil-Paste Electrical Conductivities: Sensitivity Analysis of Models

Soil Science Society of America Journal, 1989

Research paper thumbnail of Assessing irrigation/drainage/salinity management using spatially referenced salinity measurements

Agricultural Water Management, 1997

A unique technology-package for measuring the spatial distributions of salinity in irrigated soil... more A unique technology-package for measuring the spatial distributions of salinity in irrigated soils and fields and for evaluating the appropriateness of some related irrigation-, drainage- and salinity control-management practices is described. This assessment technology is based on the use of: (1) geophysical-instrumental systems for intensively measuring bulk soil electrical conductivity and associated spatial coordinates; (2) statistical algorithms for site selection and salinity calibration; and (3) algorithms for data analysis and graphical display to facilitate interpretation. Results are presented to demonstrate some of the utility of the technology. Additionally, examples are given which show that much of the apparent chaos observed in the spatial pattern of soil salinity in irrigated fields is man-induced and related to such management practices as irrigation, drainage, and tillage.

Research paper thumbnail of Determining Soil Salinity from Soil Electrical Conductivity using Different Models and Estimates

Soil Science Society of America Journal, 1990

... Title Determining soil salinity from soil electrical conductivity using different models and ... more ... Title Determining soil salinity from soil electrical conductivity using different models and estimates. Authors Rhoades, JD; Shouse, PJ; Alves, WJ; Manteghi, NA; Lesch, SM JournalSoil Science Society of America Journal 1990 Vol. 54 No. 1 pp. ...

Research paper thumbnail of Locating Sampling Sites for Salinity Mapping

Soil Science Society of America Journal, 1990

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