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44 results on '"Nelson, Roger L."'

6. Estimating Biomass and Yield Using METRIC Evapotranspiration and Simple Growth Algorithms

Author

Khan, Azeem, Stöckle, Claudio O., Nelson, Roger L., Peters, Troy, Adam, Jennifer C., Lamb, Brian, Chi, Jinshu, Waldo, Sarah, Khan, Azeem, Stöckle, Claudio O., Nelson, Roger L., Peters, Troy, Adam, Jennifer C., Lamb, Brian, Chi, Jinshu, and Waldo, Sarah

Abstract

Crop models are used to assess crop yield under prescribed scenarios and at scales varying from point to field to region and beyond. The use of models to evaluate the performance of agricultural systems, as they exist in the real world, can be challenging and plagued with constraints. This is due to the difficulty in characterizing the spatial variability across the landscape of crops, soils, weather, management, miscellaneous stress factors, and the initial state of the system. We propose the use of actual evapotranspiration (ETa) estimated from remote sensing images and simple crop growth-transpiration algorithms as an alternative to the use of standalone crop models for real-world yield assessment. In this study, we combined ETa estimates from METRIC (Mapping Evapotranspiration at High Resolution with Internalized Calibration) with simple crop growth algorithms extracted from the CropSyst model to estimate biomass production and yield at high resolution (30 by 30 m). We tested this approach in four dryland agriculture sites in eastern Washington State with contrasting annual precipitation. All sites were equipped with an eddy covariance flux tower for ground ETa estimation. The proposed approach was able to provide good estimates of ETa, seasonal change of aboveground biomass and yields at all sites when compared with observations for a 3-year period, collectively including five different annual crops. Because estimations are made at high resolution, they can be scaled up to field or regional scales. Advantages and limitations of the proposed approach are discussed.

Published
2019

8. Universal versus selective gestational diabetes screening: application of 1997 American Diabetes Association recommendations

Author

Danilenko-Dixon, Diana R., Van Winter, Jo T., Nelson, Roger L., and Ogburn, Paul L.

Subjects
Diabetes in pregnancy -- Diagnosis, Pregnant women -- Testing, Health
Abstract

Screening only pregnant women 25 years or older for gestational diabetes would detect 90% of all such cases, according to a study from the Mayo Clinic. In this study, 18,504 women were tested, regardless of their age. Only 3% of gestational diabetes cases would be missed if following the 1997 American Diabetes Association guidelines.

Published
1999

10. Sequelae of unrecognized gestational diabetes

Author

Adams, Kristina M., Li, Hongzhe, Nelson, Roger L., Ogburn, Paul L., and Danilenko-Dixon, Diana R.

Subjects
Diabetes in pregnancy -- Complications, Fetal macrosomia -- Risk factors, Dystocia -- Risk factors, Health
Abstract

Unrecognized gestational diabetes can lead to difficult labor, infants that are large for their age and birth trauma. Gestational diabetes is diabetes that begins during pregnancy. Researchers compared birth outcomes in 472 women with gestational diabetes, including 16 who were not diagnosed until after their pregnancy. These 16 women were more likely to have large for gestational age infants, difficult labor and birth trauma. This was true even in those who were not overweight to begin with.

Published
1998

19. ET_CSDLL

Author

Donatelli, Marcello, primary, Stöckle, Claudio O., additional, Nelson, Roger L., additional, and Bellocchi, Gianni, additional

Published
2003
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22. Evapotranspiration of Irrigated Crops under Warming and Elevated Atmospheric CO 2 : What Is the Direction of Change?

Author

Scarpare, Fabio V., Rajagopalan, Kirti, Liu, Mingliang, Nelson, Roger L., and Stöckle, Claudio O.

Subjects
ATMOSPHERIC carbon dioxide, GENERAL circulation model, CROPS, EVAPOTRANSPIRATION, AGRICULTURAL climatology, WINTER wheat
Abstract

Future changes in crop evapotranspiration (ETc) are of interest to water management stakeholders. However, long-term projections are complex and merit further investigation due to uncertainties in climate data, differential responses of crops to climate and elevated atmospheric CO2, and adaptive agricultural management. We conducted factor-control simulation experiments using the process-based CropSyst model and investigated the contribution of each of these factors. Five major irrigated crops in the Columbia Basin Project area of the USA Pacific Northwest were selected as a case study and fifteen general circulation models (GCM) under two representative concentration pathways (RCP) were used as the climate forcing. Results indicated a wide range in ETc change, depending on the time frame, crop type, planting dates, and CO2 assumptions. Under the 2090s RCP8.5 scenario, ETc changes were crop-specific: +14.3% (alfalfa), +8.1% (potato), −5.1% (dry bean), −8.1% (corn), and −12.5% (spring wheat). Future elevated CO2 concentrations decreased ETc for all crops while earlier planting increased ETc for all crops except spring wheat. Changes in reference ET (ETo) only partially explains changes in ETc because crop responses are an important modulating factor; therefore, caution must be exercised in interpreting ETo changes as a proxy for ETc changes. [ABSTRACT FROM AUTHOR]

Published
2022
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25. The OGTT.

Author

Nelson, Roger L.

Published
1989

43. Use of Adrenal Biopsy in Diagnosing Adrenoleukomyeloneuropathy

Author

Weiss, Gary M., Nelson, Roger L., O'Neill, Brian P., Carney, J. Aiden, and Edis, Anthony J.

Abstract

• A 22-year-old man was seen with Addison's disease, psychosis, and neurologic abnormalities. A tentative diagnosis of adrenoleukomyeloneuropathy was made. Because of his age, negative family history, and the potentially serious prognosis of this disorder, the diagnosis was verified with an adrenal biopsy. We believe this procedure is the method of choice in confirming the sporadic, atypical case of adrenoleukomyeloneuropathy.

Published
1980
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44. Letters to the Editor.

Author

Nelson, Roger L.

Subjects
LETTERS to the editor, NEWSPAPER sections, columns, etc.
Abstract

Presents letter to the editor published in the October 2003 issue of the periodical "Journal of Singing" in the U.S. Various contributions of the National Association of Teachers of Singing; Judgment of music theater category.

Published
2003

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