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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
681

Nitrogen fixation by Myrica asplenifolia L.

Fessenden, Robert J. January 1976 (has links)
No description available.
682

Human milk storage conditions in regard to safety and optimal preservation of nutritional properties

Abramovich, Milana 17 January 2011 (has links)
This study assessed losses of the linoleic, alpha-linolenic, arachidonic and docosahexaenoic fatty acids, vitamin B2 and total vitamin C during storage of human milk, pasteurized and unpasteurized. The volatile compounds’ pattern change was monitored. The storage conditions were 8 days at 4oC and 6 months at -20oC and at -80oC, with and without limitation of oxygen. Fatty acids were analyzed by GC-FID; vitamins - by HPLC; volatile compounds’ concentration patterns were obtained using the e-nose machine; ANOVA tests were applied, with the statistical significance assigned to P<0.05. The official recommendations for human milk storage of 5-8 days at 4oC and of 6 or more months at -20oC are appropriate in regard to the analyzed nutrients and can be extended for pasteurized human milk storage. Oxygen limitation and -80oC temperature have no clear benefit for nutrient preservation. The evaluation of the odour cannot be based exclusively on the e-nose analysis.
683

Coupling Nitrogen Transport and Transformation Model with Land Surface Scheme SABAE-HW and its Application on the Canadian Prairies

Hejazi, Seyed Alireza 10 January 2011 (has links)
The main goal of this research is to contribute to the understanding of nutrient transport and transformations in soil and its impact on groundwater on a large scale. This thesis specifically integrates the physical, chemical and biochemical nitrogen transport processes with a spatial and temporal Land Surface Scheme (LSS). Since the nitrogen biotransformation kinetics highly depends on soil moisture and soil temperature, a vertical soil nitrogen transport and transformations model was coupled with SABAE-HW. The model provides an improved interface for groundwater modeling to simulate soil moisture and soil temperature for a wide range of soil and vegetation. It is assumed that the main source of organic N is from animal manure. A-single-pool nitrogen transformation is designed to simulate nitrogen dynamics. Thus, the complete mathematical model (SABAE-HWS) is able to investigate the effects of nitrogen biochemical reactions in all seasons. This thesis reports the first field comparison of SABAE-HW using an extensive ten-year data set from BOREAS/BERMS project located in Saskatchewan, Canada. The performance of SABAE-HWS is calibrated and verified using 3 years (2002-2004) data from Carberry site in Canada, Manitoba. The effects of three rates of hog manure application, 2500, 5000, and 7500 gal/acre, was investigated to study the distribution of soil ammonium and soil nitrate within the 120 cm of soil profile. The results clearly showed that there is a good agreement between observed and simulated soil ammonium and nitrate for all treatment at the first two years of study. However, it was found a significant difference between observations and simulations at lower depths for 7500 gal/acre by the end of growing season of 2004. Also, 10 years climate data from OJP site was used to evaluate the effect of manure rates on the distribution of soil nitrate at Carberry site. The results indicated that to minimize the risk of nitrate leaching, the rate of manure application, accumulated soil nitrogen from earlier applications and the atmospheric conditions should be all taken into account at the same time. Comparing the results of SABAE-HWS and SHAW model also showed the importance of the crop growth model in simulating soil NH4-N and NO3-N.
684

The absorption of nitrogen dioxide by condensing water droplets

Herrmann, John Patrick 12 1900 (has links)
No description available.
685

Evaluation of nitrogen losses in the form of ammonia from surface applied manure

Brunke, Richard R. January 1986 (has links)
No description available.
686

Aromatic nucleophilic nitration

Thompson, Claire January 1996 (has links)
No description available.
687

Nitrate reduction by oral bacteria : a role in host defence against pathogens?

Li, Hong January 2001 (has links)
No description available.
688

Estimation of nitrogen mineralization from solid beef cattle and liquid swine manures

Sayem, S.M. 02 May 2014 (has links)
Manure nitrogen (N) mineralization is the process that converts organic N to plant available N and is influenced by environmental and soil factors. Field and laboratory incubation studies were conducted to determine the N mineralization and fertilizer equivalence of locally available manures. Available N from solid beef manure amendments (SBM) increased as the studies progressed due to mineralization. Liquid swine manure (LSM) behaved similarly to commercial fertilizer with high initial concentrations of ammonium N which declined continuously as the studies progressed. Manure N mineralization varied significantly (p<0.01) due to the influence soil moisture, manure types and study period as well as their interaction. The fertilizer equivalence of SBM in loamy soil was initially low compared to LSM and finally approached 80 % of ammonium nitrate fertilizer. These studies suggested that manure N mineralization requires emphasis on the initial form of N in manures besides soil moisture, soil temperature, and aeration.
689

Phosphorus and nitrogen in the Al-Hawizeh marshes, southern Iraq

Mahamed, Sama 06 November 2014 (has links)
Hour Al-Hawizeh is one of the biggest marshes within the Mesopotamian marshes of southern Iraq. This Hour has been functioned for centuries under natural conditions providing resources for local people, important habitat for migrating birds, and a major source of the natural hydrology in the Middle East. In the early 1990???s, the Mesopotamian marshes were intentionally drained. This disaster has adversely affected the biodiversity of the marshes. In April 2003, these marshes were inundated again with the hope that this ecosystem will return to its previous nature. This new condition led many of scientist and researchers to investigate how the ecosystem behaves after being re-flooded and to assess the restoration progress of these re-flooded areas. In this study, I focused on phosphorus (P) and nitrogen (N), as they are two of the commonly limiting factors for the health of any aquatic system. The main goals of this study are: 1) to determine the TP and TN budget in relation to the water budget of Hour Al-Hawizeh and examine how the water inlets contribute the water supply and nutrient load and determine whether Hour Al-Hawizeh acts as a sink or a source of P and N, whether this varies among sections of the marsh with different flooding histories, and its consequences for the restoration of the marsh, 2) to investigate the TP and TN variation and composition in eight marshes within Hour Al-Hewaizah and investigate the relationship of the phytoplankton component, as indicated by chlorophyll-a, with TN and TP concentrations in Hour Al-Hawizeh. TP and TN budgets suggested that Hour Al-Hawizeh acts as a sink for phosphorus and source for nitrogen. In this study, the annual retention of TP was approximately 128 tons, while annual release of TN was 237 tons. TP and TN concentration within the eight marshes within Hour Al- Hawizeh exhibited different seasonal patterns during the study period, which is likely attributable to with the variable sources and transformations of phosphorus and nitrogen in the selected marshes. In addition, the study revealed a significant relationship between chlorophyll-a concentration and TP and TN. However, the relationship between chlorophyll-a and TN was stronger. The differences in water quality parameters, TP, TN, and chlorophyll-a concentration between the marshes within Hour Al-Hawizeh suggest that Hour Al-Hawizeh is not a one homogeneous system and each marsh acts as a unique system.
690

Human milk storage conditions in regard to safety and optimal preservation of nutritional properties

Abramovich, Milana 17 January 2011 (has links)
This study assessed losses of the linoleic, alpha-linolenic, arachidonic and docosahexaenoic fatty acids, vitamin B2 and total vitamin C during storage of human milk, pasteurized and unpasteurized. The volatile compounds’ pattern change was monitored. The storage conditions were 8 days at 4oC and 6 months at -20oC and at -80oC, with and without limitation of oxygen. Fatty acids were analyzed by GC-FID; vitamins - by HPLC; volatile compounds’ concentration patterns were obtained using the e-nose machine; ANOVA tests were applied, with the statistical significance assigned to P<0.05. The official recommendations for human milk storage of 5-8 days at 4oC and of 6 or more months at -20oC are appropriate in regard to the analyzed nutrients and can be extended for pasteurized human milk storage. Oxygen limitation and -80oC temperature have no clear benefit for nutrient preservation. The evaluation of the odour cannot be based exclusively on the e-nose analysis.

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