Asteroid Affirmative

Disease !  Extinction

Despite the importance of the discovery of the “facilitating” cell, it is not what Dr Ben-Abraham wants to talk about. There is a much more pressing medical crisis at hand – one he believes the world must be alerted to: the possibility of a virus deadlier than HIV. If this makes Dr Ben-Abraham sound like a prophet of doom, then he makes no apology for it. AIDS, the Ebola outbreak which killed more than 100 people in Africa last year, the flu epidemic that has now affected 200,000 in the former Soviet Union – they are all, according to Dr Ben-Abraham, the “tip of the iceberg” Two decades of intensive study and research in the field of virology have convinced him of one thing: in place of natural and man-made disasters or nuclear warfare, humanity could face extinction because of a single virus, deadlier than HIV. “An airborne virus is a lively, complex and dangerous organism,” he said. “It can come from a rare animal or from anywhere and can mutate constantly. If there is no cure, it affects one person and then there is a chain reaction and it is unstoppable. It is a tragedy waiting to happen.” That may sound like a far-fetched plot for a Hollywood film, but Dr Ben-Abraham said history has already proven his theory. Fifteen years ago, few could have predicted the impact of AIDS on the world. Ebola has had sporadic outbreaks over the past 20 years and the only way the deadly virus – which turns internal organs into liquid – could be contained was because it was killed before it had a chance to spread. Imagine, he says, if it was closer to home: an outbreak of that scale in London, New York or Hong Kong. It could happen anytime in the next 20 years – theoretically, it could happen tomorrow. The shock of the AIDS epidemic has prompted virus experts to admit “that something new is indeed happening and that the threat of a deadly viral outbreak is imminent”, said Joshua Lederberg of the Rockefeller University in New York, at a recent conference. He added that the problem was “very serious and is getting worse”. Dr Ben-Abraham said: “Nature isn’t benign. The survival of the human species is not a preordained evolutionary programme. Abundant sources of genetic variation exist for viruses to learn how to mutate and evade the immune system.” He cites the 1968 Hong Kong flu outbreak as an example of how viruses have outsmarted human intelligence. And as new “mega-cities” are being developed in the Third World and rainforests are destroyed, disease-carrying animals and insects are forced into areas of human habitation. “This raises the very real possibility that lethal, mysterious viruses would, for the first time, infect humanity at a large scale and imperil the survival of the human race,” he said.

UV-B Radiation ! – Plant Growth

UVB Radiation of less than 20% has the capability of significantly decreasing biomass in key plans.

World Health Oganization 94 (Environmental Health Criteria 160, Ultraviolet Radiation, date n/a, http://www.inchem.org/documents/ehc/ehc/ehc160.htm#SectionNumber:11.2, znf)

The growth of many plant species is reduced by enhanced levels of UVB. The main components of plants affected by UVB are shown in figure 11.1 (UNEP 1989). The ozone filter technique was used to simulate a relative solar UVB enhancement of 20% by providing 54.4 kJ m-2 day-1 (unweighted) or 5.1 kJ m-2 day-1 of biologically effective radiation (UVBBE) through one cuvette and 45.3 kJ m-2 day-1 (unweighted) or 3.6 kJ m-2 day-1 UVBBE through the other cuvette (Tevini et al., 1991b). These were average values measured from May 1990 to August 1990 and are equivalent to an ozone depletion of approximately 10%. Plant height, leaf area, and the dry weight of sunflower, corn, and rye seedlings were significantly reduced, while oat seedling remained almost unaffected (Tevini et al., 1991b). The reduction of hypocotyl growth of sunflower seedlings under artificial UVB irradiation is associated with a UV dependent destruction of the growth regulator indole-3-acetic acid (IAA) and the formation of growth inhibiting IAA photoproducts. The inhibition of elongation in UV-irradiated sunflower seedlings might also be due to the action of peroxidases working as IAA-oxidase, causing a decrease in cell wall extensibility of the hypocotyl epidermis (Ros, 1990). Shading of shoot apex was shown to reduce UVB induced reduction in growth of Vigna seedlings (Kulandaivelu et al., 1993). 11.2.3 Effects on plant function When high UVB irradiances were used in combination with low levels of white light, such as commonly found in growth chambers, effects on photosynthesis were generally deleterious. However, even in the presence of higher levels of white light in green houses and in the field, reductions in photosynthesis of up to 17% were reported in the UVB sensitive soybean cultivar Essex when supplied with UVB equivalent to an 18% ozone depletion (Murali & Teramura, 1987). Solar UVB also reduced net photosynthesis in sunflower seedlings by about 15% when a 12% ozone depletion was simulated by using the ozone filter technique (Tevini et al., 1991c). One reason for the reduction in overall photosynthesis might be due to stomatal closure by enhanced UVB. Recent studies reveal the effects of UVB radiation on tropical plants. Rice is among the most important tropical crops in the world. Sixteen rice ( Oryza sativa L.) cultivars from several different geographical regions when grown for 12 weeks in greenhouses with supplemental levels of UVB exposure equivalent to 20% ozone depletion over the equator (15.7 kJ m-2 day-1 UVBBE) showed alterations in biomass, morphology, and photosynthesis. Approximately one-third of all cultivars tested showed a statistically significant decrease in total biomass with increased UVB exposure. Photosynthetic capacity declined for some cultivars, but only a weak relationship existed between changes in photosynthesis and biomass with increasing UVB exposure. In one of the rice cultivars tested, total biomass significantly increased by 20% when grown under enhanced levels of UVB exposure. Therefore, despite the fact that the effects of UVB are generally damaging, in some cases, it has been reported to have a stimulating effect. Such positive growth effects are presently not easily explainable. Results from this experiment indicate that 1) a number of rice cultivars are sensitive to increases in UVB exposure; 2) the diversity exhibited by rice in response to increased levels of UVB suggests that selective breeding might be successfully used to develop UVB tolerant rice cultivars. Other preliminary screening studies on rice seedlings also corroborate these observations (Coronel et al., 1990).

Directory: 2011
2011 -> Enterprise Network Management iPost: Implementing Continuous Risk Monitoring at the Department of State
2011 -> Voices of the Old Sea Norman Lewis
2011 -> Malevil Robert Merle
2011 -> The Elephant Keeper’s Children Peter Hoeg
2011 -> January 1: Ecstasy zZz January 2: King of Anything Sara Bareillis
2011 -> Tracks, Mixes, Masters, and More!: Analyzing Preservation Priorities for Multitrack Recordings
2011 -> Department of Electrical Engineering 2011 Annual Report
2011 -> Jv packet •Mars Colonization Affirmative •Mars Colonization Negative
2011 -> Asian Pacific Mathematical Olympiad(apmo)
2011 -> Registration Form (Rev. 8-86) omb no. 1024-0018

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