• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 163
  • 135
  • 43
  • 30
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • Tagged with
  • 489
  • 66
  • 51
  • 46
  • 44
  • 43
  • 39
  • 39
  • 35
  • 32
  • 32
  • 27
  • 27
  • 26
  • 26
  • 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.
111

Studies on antibiotics, heavy metal ions and agricultural chemicals resistance of Pseudomonas aeruginosa collected from environments.

Lin, Fang-Lan 16 June 2003 (has links)
In the present work, in order to evaluate the seriousness of environmental pollution caused by antibiotics abuse, and by industrial and agricultural pollutants, different strains of Pseudomonas aeruginosa were collected from industrial area, abandoned metal hardware factory, fishery pool, vegetable garden and fruit farm, river mud, and different origins of water bodies in southern Taiwan. The organisms were analyzed for their drug resistance against a variety of antibiotics and agricultural pesticides. They were also analyzed for endurance toward heavy metal ions including mercury, cadmium, arsenic and chromium ions. As the data indicated that, in terms of their resistance to clinical frequently used antibiotics, about 40% of the Pseudomonas aeruginosa isolates of the environment have developed resistance against Cefoperazone, about 20% showed resistance against Tobramycin, and only about 4% revealed resistance against Imipenem and Ceftazidime. As to heavy metal ion resistance, about 27% of the environmental Pseudomonas aeruginosa strains demonstrated resistance against mercury ion, and about 10% exhibited resistance against arsenic ions, whereas no resistance was observed toward chromium ions. In terms of resistance to agricultural pesticides, about 36% environmental isolates demonstrated resistance against Paraquat, but none of the tested Pseudomonas aeruginosa show resistance toward Cartap and Methomyl. To sum up the findings, so far only minor portion of Pseudomonas aeruginosa acquired drug resistance, therefore, immediate measure is required to prevent the spreading of drug-resistant Pseudomonas aeruginosa . It is suggested that all the physicians and pharmacists to prescribe antibiotics should be more careful and responsible manner. Meanwhile, it would also call on the restrained usage of pesticides and antibiotics in the livestock and aquatic product industry, and strengthening pollution control in the industrial sector.
112

Development of a method to determine vapor pressure data of low volatile chemicals from a Knudsen effusion technique

Harshman, Andrew R 01 June 2007 (has links)
Vapor pressure data are vital to understanding impacts that substances, specifically pesticides, may exert on the environment. They enter into atmospheric deposition models for such chemicals which determine the fate and transport of these species in the environment. At normal application temperatures (i.e. room temperature) the vapor pressures of many of these chemicals are too low to be determined by conventional means. An isothermal Knudsen effusion technique was designed and developed in our laboratory for such measurements. The effusion mass as a function of time is measured in our technique using a thickness shear mode (TSM) acoustic wave sensor, which allows for extremely high (few nanograms) sensitivity. This sensitivity allows for much more rapid determination of low vapor pressures (10-1 to 10-5 Pa) than is possible by other Knudsen effusion techniques. Basing the effusion mass measurement on the TSM sensor as in our apparatus eliminates the typically seen dependence on vibration in conventional microbalance-based effusion techniques. Full design details of our apparatus and specifically the Knudsen cell, based on original equations derived by Knudsen, and many corrections that have been noted in the literature for cell and effusion-hole dimensions, are presented. The accuracy of our methodwas tested by a comparison of published vapor pressure data to vapor pressure data acquired in our laboratory with measurements on naphthalene and catechol.
113

Keep Milk Free of Pesticides, Antibiotics, and Related Materials

Van Sant, W. R., Roney, J. N., Witt, J. M., Stull, J. W. 05 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project. / Revised.
114

Antibiotics, Pesticides, and Related Materials in Milk

Stull, J. W., Van Sant, W. R., Witt, J. M., Roney, J. N. 06 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
115

The effect of thyroprotein on pesticide excretion and distribution of fatty acids in the milk of the lactating bovine

Sullivan, Lawrence M., 1939- January 1967 (has links)
No description available.
116

Utgör omgivande lantbruk någon risk för Skottorps vattentäkt?

Sjödin, Sanna January 2015 (has links)
The intensification of agriculture through Europe has led to a lot of environmental issues. Among these are the increased use of fertilizer and pesticides which also constitutes a risk for many water resources. This is mainly due to the leakage of nitrate and pesticides to the water which makes it unsuitable for drinking. The aim of this study was to investigate whether the nearby agriculture constituted a risk in the catchment of Skottorp. If risks were found, the study was also aiming to evaluate possible measures that could be taken. An additional aim was to find out whether a co-operative agreement between the local authorities responsible for the catchment and the farmers would be a possible solution in case of future problems. For the study, water data related to agriculture was analyzed statistically and interviews were performed with the farmers. The study shows that there are no imminent risks to the water in the catchment related to agriculture, which makes measures unnecessary. If problems would arise in the future the study also shows that co-operative agreements are a suitable course of action.
117

Effect of water table management on pesticide movement in two Québec soils

Arjoon, Diane S. January 1993 (has links)
A three year field study was undertaken to assess the influence of water table management, namely subsurface irrigation and controlled drainage, on the movement of pesticides through the soil profile into ground water. The herbicides under investigation were prometryn on an organic soil, and metolachlor on a sandy soil. Both soil and groundwater were collected and analyzed. The results presented are those obtained in the first two years of the project. / In the organic soil, herbicide leaching was greatly reduced due to the management of the water table. The pesticide remained higher in the soil profile, preventing leaching to the drains and allowing degradation. / The opposite effect appeared to have occurred in the sandy soil. The higher water table resulting from subsurface irrigation may have induced the leaching of the contaminant into lower soil levels and into the ground water. The high water solubility of the herbicide metolachlor, in conjunction with low microbial activity, may have played a role in this phenomenon.
118

"The mode of action of Bacillus thuringiensis (Berliner) against the sheep louse, Bovicola ovis (Schrank)" /

Hill, Catherine Alexandra. January 1998 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Crop Protection, 1998? / Includes bibliographical references (leaves 120-145).
119

Patch exploitation by the parasitoids of Plutella xylostella (L.): from individual behaviour to population dynamics /

Wang, Xin-geng. January 2001 (has links) (PDF)
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001. / Includes bibliographical references (leaves 204-230).
120

The microbiology of railway tracks : towards a rational use of herbicides on Swedish railways /

Cederlund, Harald, January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Page generated in 0.0501 seconds