Science and technology /

Folded cover.

Science and technology : a report to the Congress.

Subtitle varies.

National engineering and science policy [microform] : hearing before the Subcommittee on Science, Research and Technology of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, first session, December 14, 1981.

"No. 80."

International Congress of Arts and Science.

Contents.--v. 1. Philosophy and metaphysics.--v. 2. Aesthetics and mathematics.--v. 3. History and law.--v. 4. Law and religion.--v. 5. History of language.--v. 6. Literature and art.--v. 7. Physics and chemistry.--v. 8. Astronomy and earth sciences.--v. 9. Biology.--v. 10. Anthropology and mental science.--v. 11. Medicine.--v. 12. Medicine and technology.--v. 13. Economics and social regulation.--v. 14. Jurisprudence and social science.--v. 15. Secular and religious education.

Papers and proceedings of the annual meeting of the Canadian Political Science Association.

No meetings held 1914-1929.

Impact of national security considerations on science and technology [microform] : hearing before the Subcommittee on Science, Research, and Technology and the Subcommittee on Investigations and Oversight of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, March 29, 1982.

"No. 110."

Science and engineering, education and manpower [microform] : hearing before the Subcommittee on Science, Research, and Technology of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, February 11, 1982.

"No. 93."

Hard red spring and durum wheat quality /

Mode of access: Internet.

Science and learning in France, with a survey of opportunities for American students in French universities;

Mode of access: Internet.

Oversight of science and technology policy : joint hearing before the Subcommittee on Science, Technology, and Space of the Senate Committee on Commerce, Science, and Transportation and the Subcommittee on Science, Research, and Technology of the House Committee on Science and Technology ... February 14, 1978

"Serial no. 95-77."

Integration of science and technology in CEMA /

Mode of access: Internet.

Science and technology : annual report to the Congress / National Science Foundation

Mode of access: Internet.

Science and technology report; annual report to the Congress, submitted in accordance with the National science and technology policy, organization and priorities act of 1976

"Printed for the use of the Committee on Science and Technology."

Timing, magnitude, and location of initial soluble aluminum injuries to mungbean roots

Despite a century's knowledge that soluble aluminum (Al) is associated with acid soils and poor plant growth, it is still uncertain how Al exerts its deleterious effects. Hypotheses include reactions of Al with components of the cell wall, plasmalemma, or cytoplasm of cells close to the root tip, thereby reducing cell expansion and root growth. Digital microscopy was used to determine the initial injuries of soluble Al to mungbean (Vigna radiata L.) roots. Roots of young seedlings were marked with activated carbon particles and grown in 1 mm CaCl2 solution at pH 6 for ca. 100 min (control period), and AlCl3 solution was added to ensure a final concentration of 50 muM Al (pH 4). Further studies were conducted on the effects of pH 4 with and without 50 muM Al. Four distinct, but possibly related, initial detrimental effects of soluble Al were noted. First, there was a 56-75% reduction in the root elongation rate, first evident 18-52 min after the addition of Al, root elongation continuing at a decreased rate for ca. 20 It. Decreasing solution pH from 6 to 4 increased the root elongation rate 4-fold after 5 min, which decreased to close to the original rate after 130 min. The addition of Al during the period of rapid growth at pH 4 reduced the root elongation rate by 71% 14 min after the addition of Al. The activated carbon marks on the roots showed that, during the control period, the zone of maximum root growth occurred at 2,200-5,100 mum from the root tip (i.e. the cell elongation zone). It was there that Al first exerted its detrimental effect and low pH increased root elongation. Second, soluble Al prevented the progress of cells from the transition to the elongation phase, resulting in a considerable reduction of root growth over the longer term. The third type of soluble Al injury occurred after exposure for ca. 4 h to 50 mum Al when a kink developed at 2,370 mum from the root tip. Fourth, ruptures of the root epidermal and cortical cells at 1,900-2,300 mum from the tip occurred greater than or equal to4.3 h after exposure to soluble Al. The timing and location of Al injuries support the contention that Al initially reduces cell elongation, thus decreasing root growth and causing damage to epidermal and cortical cells.

A simple regional-scale model for forecasting sorghum yield across North-Eastern Australia

Sorghum is the main dryland summer crop in NE Australia and a number of agricultural businesses would benefit from an ability to forecast production likelihood at regional scale. In this study we sought to develop a simple agro-climatic modelling approach for predicting shire (statistical local area) sorghum yield. Actual shire yield data, available for the period 1983-1997 from the Australian Bureau of Statistics, were used to train the model. Shire yield was related to a water stress index (SI) that was derived from the agro-climatic model. The model involved a simple fallow and crop water balance that was driven by climate data available at recording stations within each shire. Parameters defining the soil water holding capacity, maximum number of sowings (MXNS) in any year, planting rainfall requirement, and critical period for stress during the crop cycle were optimised as part of the model fitting procedure. Cross-validated correlations (CVR) ranged from 0.5 to 0.9 at shire scale. When aggregated to regional and national scales, 78-84% of the annual variation in sorghum yield was explained. The model was used to examine trends in sorghum productivity and the approach to using it in an operational forecasting system was outlined. (c) 2005 Elsevier B.V. All rights reserved.