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101.
Satisfying future water demands for agriculture 总被引:2,自引:0,他引:2
The global demand for water in agriculture will increase over time with increasing population, rising incomes, and changes in dietary preferences. Increasing demands for water by industrial and urban users, and water for the environment will intensify competition. At the same time, water scarcity is increasing in several important agricultural areas.We explore several pathways for ensuring that sufficient food is produced in the future, while also protecting the environment and reducing poverty. We examine four sets of scenarios that vary in their focus on investments in rainfed agriculture and irrigation, and the role of international trade in adjusting for national disparities in water endowments. Rainfed agriculture holds considerable potential but requires adequate mechanisms to reduce inherent risks. Irrigation expansion is warranted in places where water infrastructure is underinvested such as sub-Saharan Africa. In South Asia the scope for improving irrigation performance and water productivity is high. International trade can help alleviate water problems in water-scarce areas, subject to economic and political considerations. We examine also a regionally optimized scenario that combines investments in rainfed and irrigated agriculture with strategic trade decisions. Compared to ‘business as usual’, this scenario reduces the amount of additional water required to meet food demands by 2050 by 80%. Some of that water could be made available for the environment and other sectors. We conclude that there are sufficient land and water resources available to satisfy global food demands during the next 50 years, but only if water is managed more effectively in agriculture. 相似文献
102.
Tamaki Uyama David Renaud Stephen LeBlanc J. McClure Durda Slavic Charlotte Winder David Kelton 《The Canadian veterinary journal. La revue veterinaire canadienne》2022,63(3):260
The objectives of this study were to i) describe Escherichia coli and Salmonella isolates; ii) investigate the temporal trends in antimicrobial resistance (AMR) profiles; and iii) evaluate the impact of season and age on these AMR profiles from diagnostic and post-mortem samples in Ontario calves ≤ 2-months-old submitted from 2007 to 2020 to the Animal Health Laboratory in Guelph, Ontario, Canada. Antimicrobial susceptibility testing results were measured by the Kirby-Bauer disk diffusion method. A total of 1291 isolates with AMR profiles were obtained from calves, with E. coli (n = 434) and Salmonella (n = 378) being the most common bacteria characterized for AMR. For E. coli, 79% of isolates tested showed a positive result in F5/K99, whereas for Salmonella isolates, S. Typhimurium (33%) and S. Dublin (22%) were the 2 most common serotypes identified. Multivariable logistic regression models were built to evaluate AMR profiles for E. coli (n = 414) and Salmonella (n = 357) to each antimicrobial tested. Most E. coli isolates (91%) and Salmonella isolates (97%) were resistant to at least one of the antimicrobials tested. In general, E. coli and Salmonella had higher odds of resistance in calves aged ≥ 2 wk compared to 1-week-old calves, and little difference was seen in the level of resistance over the years observed or between seasons in most of the antimicrobials tested. Prospective research should investigate potential risk factors for the development of AMR in calves examples being antimicrobial use and farm management practices. 相似文献
103.
Harvey Tyler‐Walters Stuart I. Rogers Charlotte E. Marshall Keith Hiscock 《水产资源保护:海洋与淡水生态系统》2009,19(3):285-300
- 1. Methods of sensitivity assessment to identify species and habitats in need of management or protection have been available since the 1970s.
- 2. The approach to sensitivity assessment adopted by the Marine Life Information Network (MarLIN) assumes that the sensitivity of a community or biotope is dependent on the species within it. However, the application of this approach to sedimentary communities, especially offshore, is complex because of a lack of knowledge of the structural or functional role of many sedimentary species.
- 3. This paper describes a method to assess the overall sensitivity of sedimentary communities, based on the intolerance and recoverability of component species to physical disturbance. A range of methods were applied to identify the best combinations of abundant, dominant or high biomass species for the assessment of sensitivity in the sedimentary communities examined.
- 4. Results showed that reporting the most frequent species' sensitivity assessment, irrespective of the four methods used to select species, consistently underestimated the total sensitivity of the community. In contrast, reporting the most sensitive assessment from those species selected resulted in a range of biotope sensitivities from very low to very high, that was better able to discriminate between the sensitivities of the communities examined.
- 5. The assumptions behind the methodology, its limitations and potential application are discussed.
104.
Charlotte Vogel 《Genetic Resources and Crop Evolution》1963,11(1):295-332
Zusammenfassung Das Wachstum von Erbsenkeimlingen wird durch Einwirkung harter Röntgenstrahlen (ab 800 r) gehemmt, ein sofortiger Wachstumsstillstand trat auch bei höheren Dosen nicht ein. Die größte Strahlungsempfindlichkeit besitzt dabei die Wurzelmeristemzone.Bestrahlungsversuche (15–20 kr) ergaben bei mit Bleisalz vorbehandelten und nicht vorbehandelten Erbsensamen starke Schädigungen; gequollenes Saatgut ist empfindlicher als lufttrockenes. Gewächshaus- und Freilandversuche zeigen, daß sich bereits eine Dosis von 4 kr keimungs- und entwicklungshemmend auswirkt, stärkere Dosen hatten auch eine Hemmung des Wurzelwachstums zur Folge. Eine Sensibilisierung durch Bleisalzvorbehandlung des Saatgutes ist unbedeutend oder nicht nachweisbar. Unterschiede in der Wirksamkeit zwischen harter und mittelharter Strahlung sind nicht eindeutig festzustellen.
Summary The growth of pea seedlings is inhibited by the influence of hard X-rays (800 r and more). However a sudden growth stop does not happen even by application of higher doses. The most sensible zone against radiation lies within the root meristem. — Radiation experiments (15–20 kr) yielded serious damages in pea seeds, the effect being the same in by lead salts prepared seeds and in unprepared seeds. Soaked seeds are more sensible than dry ones. Experiments in the green house and in the field prove that already a dose of 4 kr is inhibiting the germination and plant development, higher doses effect also an inhibition of the root development. A sensibilization by preparation with lead salts is hardly or not at all to be proved. Differences in the effectivity between hard and middle hard radiation are not distinctly to be observed.
( 800), . . (15 000–20 000p) ; — . , 4000 ; . , . .相似文献
105.
Charlotte S Kristensen Jens Vinther Birgitta Svensmark Poul B?kbo 《Acta veterinaria Scandinavica》2014,56(1):24
Background
A field trial was carried out with two Mycoplasma hyopneumoniae vaccines in order to investigate the benefit of vaccination under field conditions in modern Danish pig production facilities with pigs being positive for M. hyopneumoniae. The M. hyopneumoniae infection of the herd was confirmed through blood samples that were positive for antibodies against M. hyopneumoniae combined with gross lesions of the lungs related to M. hyopneumoniae at slaughter and detection of M. hyopneumoniae by polymerace chain reaction in these lesions.Results
A total of 2,256 pigs from two herds were randomly divided into three groups. Group 1 received 2 mL ThoroVAX®VET, Group 2 received 1 mL Ingelvac®MycoFLEX, and Group 3 was a non-vaccinated control group. The vaccination was performed by a person who was not involved in the rest of the trial and vaccination status thereby blinded to the evaluators.The prevalence of lung lesions related to M. hyopneumoniae were significantly lower for pigs vaccinated with ThoroVAX®VET but not for pigs vaccinated with Ingelvac®MycoFLEX®, when compared to non-vaccinated pigs. There was no significant effect of vaccination on growth rate, antibiotic consumption or mortality.Conclusion
This trial demonstrated that vaccination with Thoro®VAX VET was effective in reducing the prevalence of lung lesion in pig units infected with M. hyopneumoniae. 相似文献106.
Aruna Panda Ivan Tatarov Billie Jo Masek Justin Hardick Annabelle Crusan Teresa Wakefield Karen Carroll Samuel Yang Yu-Hsiang Hsieh Michael M. Lipsky Charles G. McLeod Myron M. Levine Richard E. Rothman Charlotte A. Gaydos Louis J. DeTolla 《Comparative immunology, microbiology and infectious diseases》2014
Bacteremia is an important cause of morbidity and mortality in humans. In this study, we focused on the development of an animal model of bacteremia induced by non-typhoidal Salmonella. New Zealand White rabbits were inoculated with a human isolate of non-typhoidal Salmonella strain CVD J73 via the intra-peritoneal route. Blood samples were collected at specific time points and at euthanasia from infected rabbits. Additionally, tissue samples from the heart, lungs, spleen, gastrointestinal tract, liver and kidneys were obtained at euthanasia. All experimentally infected rabbits displayed clinical signs of disease (fever, dehydration, weight loss and lethargy). Tissues collected at necropsy from the animals exhibited histopathological changes indicative of bacteremia. Non-typhoidal Salmonella bacteria were detected in the blood and tissue samples of infected rabbits by microbiological culture and real-time PCR assays. The development of this animal model of bacteremia could prove to be a useful tool for studying how non-typhoidal Salmonella infections disseminate and spread in humans. 相似文献
107.
108.
Nadia T. Rubio-Cisneros Octavio Aburto-Oropeza Jason Murray Charlotte E. Gonzalez-Abraham Jeremy Jackson Exequiel Ezcurra 《Human Dimensions of Wildlife》2014,19(1):1-16
This article explores transnational ecosystem services in North America, provided by winter habitat for waterfowl in western Mexico coastal lagoons, and the hunting industry supported by these birds in the United States. This article shows that the number of waterfowl harvested in the United States is related to the abundance of waterfowl wintering in Mexico. On average, this flow of ecosystem services annually yields US$ 4.68 million in hunting stamp sales in the western United States. A demand curve, fitted to duck hunting licenses as a function of stamp price and previous-year waterfowl harvest, estimated US$3–6 million in consumer surplus produced in addition to governmental stamp sales revenue. This strongly suggests that waterfowl wintering habitat in western Mexico is economically valuable to U.S. hunters. Because hunters may benefit substantially from these habitats they may be willing to pay for conservation efforts in western Mexico that can result in transnational benefits received in the United States. 相似文献
109.
110.
This paper presents a method to separate harvested area and yield for irrigated crops from rainfed crops in a region, given
gross harvested area and yield, and climatic, agronomic and economic data for crops. The method is based on the principle
of general maximum entropy, which combines incomplete data, empirical knowledge and a priori information to derive desired
information. The model is applied to three large basins with aggregated climatic and agricultural conditions, and to five
counties in Texas and California. The modeled results and assessed values in these study areas are compared. While the dependability
of model outputs relies on empirical knowledge and judicious parameter estimation, the model remains reliable even for the
significant level of uncertainty produced by subjectively predetermined major parameters. The model can be applied to retriving
historical data for irrigated and rainfed crops; it can also be used for irrigated and rainfed agriculture planning based
on climatic and technological projections. Moreover, the model provides other useful information, including water allocation
by crop, water use efficiency and the impact of other agricultural inputs. 相似文献