• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 204
  • 177
  • 50
  • 48
  • 39
  • 33
  • 22
  • 14
  • 7
  • 6
  • 6
  • 6
  • 5
  • 4
  • 2
  • Tagged with
  • 751
  • 96
  • 88
  • 62
  • 58
  • 56
  • 55
  • 52
  • 48
  • 44
  • 40
  • 40
  • 39
  • 37
  • 34
  • 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.
141

Ticks and Tick-Borne Pathogens Associated with Feral Swine in Edwards Plateau and Gulf Prairies and Marshes Ecoregions of Texas

Sanders, David M. 2011 May 1900 (has links)
Feral swine (Sus scrofa domesticus) are spreading across North America at an alarming rate. Four Canadian provinces and 39 states within the continental United States now report standing populations of feral pigs. Estimates place the number of feral hogs in Texas >2M, accounting for more than half of the United States population. It is known that feral swine impact local ecology following establishment, with regard to shifts in local flora and fauna. The overall objective of this research was to investigate the role of feral swine in tick-borne pathogen transmission in Texas. The underpinning objectives were to establish host records for tick species parasitizing feral swine, determine the species assemblages associated with feral swine among different ecoregions of Texas, determine by immunoassay to which tick-borne bacteria feral pigs were being exposed, and detect the DNA of tick-borne bacteria by polymerase chain reaction assay in the event of poor or early immune response by the host. Feral pigs (N=432) were harvested from June 2008 to June 2010 using box and corral traps and by aerial gunning. Seven species of ticks, Amblyomma americanum, A. cajennense, A. maculatum, Dermacentor albipictus, D. halli, and D. variabilis; and Ixodes scapularis, were collected. Immature stages of A. cajennense and A. americanum were collected as well. All classes of feral pigs, gender by age, were infested with ticks. Serum was collected through a multi-organizational effort from 2006 to 2010 and tested by ELISA for previous exposure to tick-borne pathogens in the genera Rickettsia and Ehrlichia (N=888) and Borrelia (N=849). Prevalence percentages by immunoassay were 27.59 percent, 13.18 percent and 2.12 percent for Rickettsia, Ehrlichia, and Borrelia, respectively. Samples positive by ELISA for exposure to Borrelia were further screened by Western Blot for exposure to Borrelia turicatae. The results were equivocal in most cases. Blood samples (N=233) were collected from 2008 to 2010 and analyzed by polymerase chain reaction for the detection of the DNA of these same three genera of bacteria. Two of the samples were positive by PCR for the presence of Borrelia DNA. Texas feral swine are serving as hosts for at least seven species of ticks and are interacting with tick-borne pathogen transmissions cycles in Texas.
142

Development of refuse and wastewater treatment processes for kitchen waste

Mang, Meng-Tsung 26 August 2004 (has links)
Kitchen waste is the certain man-made trash in our daily life. It is mainly the water and oil, which is easy to decompose. In Taiwan, there is about 20,000 metric tons of family rubbish everyday, and approximately 20% to 30% of the rubbish is organic substance. Moreover, kitchen waste has a significant contribution on the total amount of rubbish. Thus, reduction and recycling of kitchen waste becomes an important issue, and it needs to be solved immediately. According to the article of Water Pollutant Prevention Act revised by Environmental Protection Bureau on 26 April 2000, wastewater discharges from apartment buildings need to be treated to meet the discharge standards. Furthermore, the discharge standards will be even more stringent in the near future. Kitchen wastewater includes liquids of kitchen rubbish, liquid of waste oil, and wastewater from grinding machines for food waste crushing. If all of the above polluting wastewater is discharged directly to the sewer system, the cost for sewer system maintenance would be huge. To protect the ecosystem and to minimize the cost of sewer system maintenance, kitchen waste and its wastewater need to be effectively treated. In this study, a kitchen waste treatment system is designed and constructed. This system is able to treat kitchen wastewater efficiently and effectively. Moreover, this system is easy to operate and maintain with less maintenance cost. The treated wastewater could meet the discharge standards with 91.4% of suspended solid removal, 91% of chemical oxygen demand (COD) removal, 96.7% of biochemical oxygen demand (BOD) removal, and 100% of grease removal.
143

Valuating and Analyzing the People for Willingness to Pay of Food Waste Recycling and Reusing-A Case Study of Kaohsiung and Taichung City

Chen, Li-chain 16 August 2005 (has links)
Food waste is one of an organic waste and contains the value of recycling and reusing. EPA shows that there are almost the amount of 4500 tons food wastes which is about 36~64% in households in Taiwan everyday. Therefore, if food wastes could be reused again, not only greatly reducing the amount of waste, decreasing the problem of odor from progressing food wastes, but also increasing the using year of landfills and incinerators. Furthermore, it can develop fully the value of multiple reusing in recycling. The study is forced on questionnaires for the residents of the city of Kaohsiung and Taichung, to know the present of recycling of food waste and its difficulty in executing a strategy. Conferring the willingness to pay and the willingness to accept of food waste recovery and if the price is different or not by Contingent Valuation Method (CVM), and moreover evaluating the potential benefit. The results of the study are as following: there are conspicuous difference in ¡§if doing something about recovery¡¨ ¡§the way of recovery¡¨ and ¡§if see any inspectors examine the classification of refuse¡¨. The most difficulties of recovery food waste in both cities are ¡§its odor and breed mosquito and fly easily¡¨ and ¡§not knowing clearly what materials should be recovered or not¡¨. About the price of the willingness to pay and the willingness to accept, the major answer shows ¡§No, I would not.¡¨ from this questionnaires. On the other hand, answers of ¡§Yes, I would like.¡¨ all hope that the pay less is better and the compensation more is better. The price of the willingness to pay of Kaohsiung residents is NT$ 41.8 dollars, and Taichung residents is NT$ 45.3 dollars. Otherwise, the higher environmental conscious the Kaohsiung residents have, the higher willing to pay. At the same time, the difficulty of recovery food waste is low comparatively. In addition, ¡§occupation¡¨ ¡§family revenue per month¡¨ ¡§cooking per week¡¨ have effect on the price of the willingness to pay and the willingness to accept. In the result of regression, some of variable parameters could affect the price of the willingness to pay. It maybe provides society for reference according the benefit in the estimating of regression. Therefore, the study hopes to provide the decision-maker more clear environmental and economical information through evaluate and analyze the willingness of pay of food waste. Furthermore, it maybe help the government to make a future policy in order to practice the food waste recovery indeed and carry out the target of reducing the amount of waste and resources recovering for a sustainable resources of food waste.
144

A model experimental system for studying prenatal stress in pigtailed macaque monkeys (Macaca nemestrina) /

Novak, Matthew S. January 2002 (has links)
Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (p. 255-271).
145

Haltungsalternativen Schwein - Haltungsalternativen für Ferkel und Mastschweine

Meyer, Eckhard, Jahn, Ines 20 March 2008 (has links) (PDF)
Die im Rahmen der Haltungsgesetzgebung diskutierten gering oder nicht perforierten Liegeflächen für Schweine führen in der Haltungspraxis in Warmställen zu bislang ungelösten Problemen. Denn ohne eine weitere Verbesserung der Haltungstechnik kommen unweigerlich die Probleme (Verschmutzung, Stallklima u.s.w.) zurück, die letztendlich zur Ablösung der früher weit verbreiteten Teilspaltenlösungen für Schweine geführt haben. Die neue Nutztierhaltungsverordnung für Schweine wird etwa 50% Liegefläche für Sauen und Mastschweine mit einem Schlitzanteil von maximal 15% vorsehen. Die Ausgestaltung dieser Flächen insbesondere der maximal mögliche Schlitzanteil wird im Zuge der weiteren Entwicklung der Haltungsvorschriften auch weiter diskutiert werden.
146

An Interdisciplinary Study on Farm Based Biogas Production in Southern Brazil

Hjort, Anders, Norin, Simon January 2008 (has links)
Today the use of anaerobic digestion technique emerges as an alternative to the conventional treatment method of pig slurry to the pig producers in Brazil because of the energy demanding intensive pig production and the negative environmental impact that arises during storage and use. The end products of AD technique are biogas as an energy source and digestate that can be used as a fertilizer. The study took place at two pig producers in southern Brazil in order to evaluate the biogas production in the area, its applications and environmental impact. The visited pig producers run a confined animal production system where the slurry that is used in the anaerobic digesters is diluted. The studied digesters are covered with an air tight flexible plastic membrane that takes the shape of a balloon where each digester has the volume of 620 m3. Sedimentation occurs inside each reactor where the temperature also fluctuates. The produced biogas is conveyed to a torch where the biogas is combusted. The results of this study show that the digesters are working properly but there is a need for mixing and constant temperature in order to optimize the process. Biogas is primarily suited for heat production and the digestate can be used as a fertilizer. Biogas production is considered to have a positive environmental impact if the biogas is used or combusted in a torch. There is also a need to apply a cover over the digestate during the storage time to avoid ammonia emissions. The approximated biogas potential for Rio Grande do Sul is nearly 100 GWh/year. For an approximated biogas potential of more consideration it is found that further studies of the housing systems in Rio Grande do Sul are needed. This is due to a greatly varying amount of degradable materials in the pig slurry from one ranch to another.
147

Omega-3 polyunsaturated fatty acids utilization in growing pigs fed flaxseed containing diets / Utilización de acidos grasos poliinsaturados omega 3 en dietas para cerdos en crecimiento alimentados con linaza

Martínez Ramírez, Héctor Ramón 15 September 2011 (has links)
Experiments were conducted to assess the effect of feeding diets containing ground flaxseed (FS); as a source of α-linolenic acid (18:3n-3), on whole body retention efficiency (RE) and disappearance (indirect measure of oxidation) of 18:3n-3, and apparent conversion (AC) of 18:3n-3 to n-3 highly unsaturated fatty acids (HUFA) in growing female pigs, using the mass balance approach (serial slaughter). Oxidation of 18:3n-3 was determined directly based on feeding U-13C-18:3n-3 and appearance of 13C in expired breath. Growth performance, composition of growth, body composition, and carcass and loin meat characteristics were not affected by feeding FS containing diets (P > 0.10). In selective pork cuts and the whole body, feeding FS increased (P < 0.10) the contents of 18:3n-3, eicosatrienoic acid (20:3n-3), eicosapentaenoic acid (20:5n-3), and docosapentaenoic acid (22:5n-3) but not docosahexaenoic acid (22:6n-3; P > 0.10). Expressed as a proportion of intake, RE of 18:3n-3 declined with duration of feeding FS (d 0 to 15 vs. d 15 to 30; P = 0.098; 68.4 vs. 52.8%). Similarly, the AC of 18:3n-3 to 20:3n-3 (8.87 vs. 5.53%) and 22:6n-3 (1.27 vs. 0.54%) was reduced over time (P < 0.05), whereas disappearance of 18:3n-3 increased over time (P = 0.074; 2.12 vs. 23.7%). At similar cumulative intake of 18:3n-3, stage of growth (25 to 50 vs. 85 to 110 kg BW) did not impact (P > 0.10) RE of 18:3n-3 and the sum of all n-3 polyunsaturated (PUFA; 95 vs. 110%), AC of 18:3n-3 to n-3 HUFA (19 vs. 22%), and oxidation of 18:3n-3 (7.0 vs. 5.6%); these parameters were influenced by dietary 18:3n-3 level. Pigs fed low dietary 18:3n-3 (0.8 g/kg) yielded both higher RE and AC of 18:3n-3 to n-3 HUFA than pigs on high dietary 18:3n-3 intake (15 g/kg). Oxidation of 18:3n-3 tended to increase with dietary 18:3n-3 level (P = 0.077; 7.97 vs. 4.67% for pigs on high and low dietary 18:3n-3, respectively) and was not affected by previous 18:3n-3 intake (P > 0.10). Feeding modest amounts of FS leads to a substantial and predictable enrichment of n-3 PUFA in pork without compromising carcass and meat quality. The content of n-3 PUFA appears to be independent of timing of feeding n-3 PUFA, providing flexibility as to when n-3 PUFA can be fed for generating n-3 PUFA enriched, value added pork. / Ontario Pork, Ontario Ministry of Agriculture, Food and Rural Affairs, Agricultural and Agri-Food Canada, and Natural Sciences and Engineering Research Council of Canada.
148

The Epidemiology of Clostridium perfringens type A on Swine Farms in Ontario and the Perceived Role in Neonatal Piglet Enteritis

Chan, Gloria 11 May 2012 (has links)
To study the distribution of Clostridium perfringens and toxin genes, 48 swine farms were visited and 354 fecal samples were collected. The isolates recovered from lactating sows, gestating sows, grower-finishers, and manure pits were less likely to possess consensus gene cpb2 compared to those from suckling pigs (P<0.05). The relative importance of different pathogens associated with neonatal piglet diarrhea was identified. A total of 237 neonatal diarrhea cases were submitted to the Animal Health Laboratory, University of Guelph between 2001 and 2010. The combined frequencies for cases involving enterotoxigenic Escherichia coli, Clostridium perfringens type A, rotavirus, and Clostridium difficile accounted for 56% of the total cases. A survey was administered to 22 practitioners and 17 pathologists for the diagnosis of C. perfringens type A. The majority (95%) of practitioners were moderately to very confident of their diagnosis, but almost half (41%) of the pathologists were not confident of their diagnosis. / Ontario Ministry of Agriculture Food and Rural Affairs
149

Enabling Large-Scale Mining Software Repositories (MSR) Studies Using Web-Scale Platforms

Shang, Weiyi 31 May 2010 (has links)
The Mining Software Repositories (MSR) field analyzes software data to uncover knowledge and assist software developments. Software projects and products continue to grow in size and complexity. In-depth analysis of these large systems and their evolution is needed to better understand the characteristics of such large-scale systems and projects. However, classical software analysis platforms (e.g., Prolog-like, SQL-like, or specialized programming scripts) face many challenges when performing large-scale MSR studies. Such software platforms rarely scale easily out of the box. Instead, they often require analysis-specific one-time ad hoc scaling tricks and designs that are not reusable for other types of analysis and that are costly to maintain. We believe that the web community has faced many of the scaling challenges facing the software engineering community, as they cope with the enormous growth of the web data. In this thesis, we report on our experience in using MapReduce and Pig, two web-scale platforms, to perform large MSR studies. Through our case studies, we carefully demonstrate the benefits and challenges of using web platforms to prepare (i.e., Extract, Transform, and Load, ETL) software data for further analysis. The results of our studies show that: 1) web-scale platforms provide an effective and efficient platform for large-scale MSR studies; 2) many of the web community’s guidelines for using web-scale platforms must be modified to achieve the optimal performance for large-scale MSR studies. This thesis will help other software engineering researchers who want to scale their studies. / Thesis (Master, Computing) -- Queen's University, 2010-05-28 00:37:19.443
150

Nutritional Characterization of Wheat Distillers Dried Grains with Solubles in Grower-Finisher Pigs

Kandel, Krishna Unknown Date
No description available.

Page generated in 0.0466 seconds