Ammonia losses estimated by an open collector from urea applied to sugarcane straw

The quantification of ammonia (NH3) losses from sugarcane straw fertilized with urea can be performed with collectors that recover the NH3 in acid-treated absorbers. Thus, the use of an open NH3 collector with a polytetrafluoroethylene (PTFE)-wrapped absorber is an interesting option since its cost is low, handling easy and microclimatic conditions irrelevant. The aim of this study was to evaluate the efficiency of an open collector for quantifying NH3-N volatilized from urea applied over the sugarcane straw. The experiment was carried out in a sugarcane field located near Piracicaba, São Paulo, Brazil. The NH3-N losses were estimated using a semi-open static collector calibrated with 15N (reference method) and an open collector with an absorber wrapped in PTFE film. Urea was applied to the soil surface in treatments corresponding to rates of 50, 100, 150 and 200 kg ha-1 N. Applying urea-N fertilizer on sugarcane straw resulted in losses NH3-N up to 24 % of the applied rate. The amount of volatile NH3-N measured in the open and the semi-open static collector did not differ. The effectiveness of the collection system varied non-linearly, with an average value of 58.4 % for the range of 100 to 200 kg ha-1 of urea-N. The open collector showed significant potential for use; however, further research is needed to verify the suitability of the proposed method.

“You Can't Always Get What You Want” : A Novel Research Paradigm to Explore the Relationship between Multiple Intentions and Behaviours

Funded by •Centre for Translational Research in Public Health •United Kingdom Clinical Research Collaboration Public Health Research Centre •British Heart Foundation •Cancer Research United Kingdom •Economic and Social Research Council •Medical Research Council •National Institute for Health

Hazardous wastes : a risk-benefit framework applied to cadmium and asbestos /

SRI project no. EGU-3561 ; EPA contract no. 68-01-2915

How basic research reaps unexpected rewards /

Mode of access: Internet.

Information, perception and regional policy /

Mode of access: Internet.

Science and engineering state profiles : Fall 1996 : detailed statistical tables /

"NSF 97-306."

Automation technology applied to public service : proceedings of a Conference on Automation Technology Applied to Public Service, held at the National Bureau of Standards, Gaithersburg, Maryland, May 21-22, 1974 /

Mode of access: Internet.

The science and technology resources of Japan : a comparison with the United States

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Trends and opportunities in materials research /

"NSF 84-17"--p. [4] of cover.

Small business guide to federal R&D funding opportunities /

"March 1986."

Individuals and families in transition : understanding change through longitudinal data : papers presented at the Social Science Research Council conference in Annapolis, Maryland, March 16-18, 1988 /

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A partial list of the publications of the National Research Council to January 1, 1922.

"Revised and reprinted from the Proceedings of the National Academy of Sciences [vol.] 7, 1921, pages 351-362."

Irrigation & drainage : a national research plan to meet competing demands and protect the environment.

Shipping list no.: 2002-0055-P.

Human science, or, Phrenology : its principles, proofs, faculties, organs, temperaments, combinations, conditions, teachings, philosophies, etc., etc. : as applied to health, its values, laws, functions, organs, means, preservation, restoration, etc. : mental philosophy, human and self improvement, civilization, home, country, commerce, rights, duties, ethics, etc. : God, His existence, attributes, laws, worship, natural theology, etc. : immortality, its evidences, conditions, relations to time, rewards, punishments, sin, faith, prayer, etc. : intellect, memory, juvenile and self education, literature, mental discipline, the senses, sciences, arts, avocations, a perfect life, etc., etc., etc. /

Mode of access: Internet.

The relationship of attitudes toward science, cognitive style, and self-concept to achievement in chemistry at the secondary school level

There is currently a crisis in science education in the United States. This statement is based on the National Science Foundation's report stating that the nation's students, on average, still rank near the bottom in science and math achievement internationally. ^ This crisis is the background of the problem for this study. This investigation studied learner variables that were thought to play a role in teaching chemistry at the secondary school level, and related them to achievement in the chemistry classroom. Among these, cognitive style (field dependence/independence), attitudes toward science, and self-concept had been given considerable attention by researchers in recent years. These variables were related to different competencies that could be used to measure the various types of achievement in the chemistry classroom at the secondary school level. These different competencies were called academic, laboratory, and problem solving achievement. Each of these chemistry achievement components may be related to a different set of learner variables, and the main purpose of this study was to investigate the nature of these relationships. ^ Three instruments to determine attitudes toward science, cognitive style, and self-concept were used for data collection. Teacher grades were used to determine chemistry achievement for each student. ^ Research questions were analyzed using Pearson Product Moment Correlation Coefficients and t-tests. Results indicated that field independence was significantly correlated with problem solving, academic, and laboratory achievement. Educational researchers should therefore investigate how to teach students to be more field independent so they can achieve at higher levels in chemistry. ^ It was also true that better attitudes toward the social benefits and problems that accompany scientific progress were significantly correlated with higher achievement on all three academic measures in chemistry. This suggests that educational researchers should investigate how students might be guided to manifest more favorable attitudes toward science so they will achieve at higher levels in chemistry. ^ An overall theme that emerged from this study was that findings refuted the idea that female students believed that science was for males only and was an inappropriate and unfeminine activity. This was true because when the means of males and females were compared on the three measures of chemistry achievement, there was no statistically significant difference between them on problem solving or academic achievement. However, females were significantly better in laboratory achievement. ^