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| SCIENCE & TECHNOLOGY |
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Climate change linked to violence among societies Limited radiation exposure doesn’t cause infertility Trends Prof Yash
Pal THIS UNIVERSE |
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Climate change linked to violence among societies A warmer world with more droughts and other climate-related disasters is likely to lead a substantial increase in violent conflict between both individuals and entire societies, a major study has found. A review of 61 detailed accounts of violence has concluded that personal disputes and wider civil conflicts increase significantly with significant changes to weather patterns, such as increases in temperature and lack of rain, scientists said. Even rather moderate shifts away from the norm result in marked increases in violence according to the study which concluded that the predicted 2°C rise in average global temperatures this century could lead to a 50 per cent increase in major violent conflicts such as civil wars. The researchers suggest that changes to the climate, and in particular increasing temperatures, are likely to lead to more frequent conflicts over increasingly sparse natural resources, in addition to the physiological stress on individuals caused by hotter weather. “We want to be careful here. We are not saying that it is inevitable that future warming will mean more conflict. We are saying that past variation in climate — and in particular, past increases in temperature — are associated with more personal and group conflict,” said Marshall Burke of the University of California, Berkeley. “It is definitely possible that future societies will be better at dealing with extreme temperatures than we are today, but we think that it is dangerous to just assume that this will be the case,” said Burke, one of the co-author of the study published in the journal Science. The research was based on a search of the academic literature for historical accounts of violent conflict, from personal violence such as murder and assaults to wider conflicts such as riots, ethnic tensions, civil war and even major collapses of civilisations going back thousands of years Conflict between groups rather than between individuals showed the strongest link to changes in the climate, the scientists said, with temperature rises being the most common risk factor — all of the 27 studies of modern societies, for instance, showed a link between hotter weather and greater violence. “We found that a one standard deviation shift towards hotter conditions causes the likelihood of personal violence to rise 4 per cent and inter-group conflict to rise by 14 per cent,” Burke said. “For a sense of scale, this kind of temperature change is roughly equal to warming an African country by 0.4°C for an entire year or warming a United States county by 3°C for a given month. These are moderate changes, but they have a sizeable impact on societies,” he said. “Our results hint at a couple factors that might link climate to conflict. The first is economic scarcity. Years of high temperature and extreme rainfall cause a deterioration in economic conditions, particularly in poor countries, and if things get really bad, people who lack other options might decide to take up arms. This seems to be a primary channel linking climate and group conflict in many agrarian societies,” he added. “At the same time, exposure to really hot temperatures also appears to cause a physiological response in how humans deal with each other: people become less trusting, more aggressive, and more violent. It’s likely that both of these mechanisms are at work, and we hope that future research will help uncover which mechanism is active in which setting,” he added. Solomon Hsiang of Princeton University, another co-author of the study, said the link between climate change and violent conflict is clear but as yet there is no clear explanation, a little like the link in the 1950s between lung cancer and smoking, which could only be explained many years later “Currently, there are several hypotheses explaining why the climate might influence conflict. For example, we know that changes in climate shape prevailing economic conditions, particularly in agrarian economies, and studies suggest that people are more likely to take up arms when the economy deteriorates, perhaps in part to maintain their livelihoods,” Hsiang said. — The Independent
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Limited radiation exposure doesn’t cause infertility ILL-informed radiographers have very exaggerated notions about the health effects of ionising radiation. They seldom get a chance to clear such doubts. Often, they are reluctant to ask whether anyone of them is likely to suffer from infertility and impotence due to radiation exposure. The occupational doses to radiographers are a very small fraction of the dose limits prescribed by the Atomic Energy Regulatory Board. No adverse effect due to radiation exposure is expected at these levels. Sterility due to radiation exposure is a deterministic effect. These effects do not occur until the radiation dose reaches a minimum threshold. For instance, the threshold dose for permanent sterility in the male for a single absorbed dose in the testes is about 3.5Gy (3,500mGy) to 6Gy (6,000mGy). Temporary sterility may occur at a lower dose of 0.15Gy (150mGy) after a few months post-exposure. It may continue for some months. (Gy is a unit of radiation dose. The radiation dose is one Gy when the radiation energy absorbed is one Joule per kg. Since Gy is large, milligray (mGy) — one thousandth of a Gy — is commonly used. The annual dose limits for radiation workers recommended by the Atomic Energy Regulatory Board (AERB) is 100mSv over five years with the maximum not to exceed 30mSv any year. For X-rays, Gy and Sv are the same. Average dose to radiation workers is only a fraction of an mSv to a few mSv). As the doses received by different groups of radiation workers are several hundred to several thousand times lower than the threshold dose, no worker will suffer sterility due to radiation exposure. Workers in India have been handling radiation sources for the past several decades. There has not been even a single instance of any worker becoming permanently sterile due to occupational radiation exposure. There is no scientific evidence that workers’ radiation exposure will cause impotence. According to WHO, 10 to 15 per cent of Indian couples are sterile. An exposed person may not get the right advice if he approaches specialist who are not equipped to offer counselling. Scholarly discussion with facts and figures on radiation and its effects has a role to play during medical counselling, but that alone may not reassure an exposed worker. This writer asked Dr Robert Brent, presently distinguished Professor of Pediatrics, Radiology and Pathology, Thomas Jefferson University, whether he has an information package to counsel radiation workers. Dr Brent has counselled thousands of patients, particularly pregnant women, on effect of radiation on the unborn, during his distinguished career over several decades. He addressed the topic at the Health Physics Society Ask the Expert (HPS ATE) website. “We have many answers on the HPS ATE website that pertain to these questions. However, the anxiety level of the questioner is usually high and they want a personal answer to their questions and concerns. Each exposure is different, as are the circumstances; generic answers do not help these contacts. They want the personal touch, and that is what we give them. The risk of cancer from low exposures of radiation is anxiety provoking and an erudite generic paragraph just does not solve the contact’s concern.” Counselling persons who were exposed to radiation is a challenging job. A specialist can do it competently if he uses all the resources available to him. The writer is former Secretary, Atomic Energy Regulatory Board
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Trends WASHINGTON: Blue-coloured night lamps have the worst effect on one’s moods while exposure to red light at night has significantly less evidence of depressive symptoms, says a new study. New research has shown how colours of night lamps could influence moods. In a study done on hamsters, researchers found that blue light had the worst effects on mood-related measures, followed closely by white. Hamsters exposed to red light at night had significantly less evidence of depressive symptoms and changes in the brain linked to depression, compared to those that experienced blue or white light.
New X-rays can sniff out gold with greater accuracy MELBOURNE: Scientists have fine-tuned a method called gamma-activation analysis, which is claimed to be far better at detecting gold than the current industry standard. It uses a metre-long tube to shoot high-powered X-rays, like those used to treat cancer patients, into fist-sized samples of ore, the Daily Telegraph reported. The rays activate traces of gold which are then read by a detector. US set to launch next Mars mission WASHINGTON: The US is set to launch its next mission to Mars in November and the spacecraft has already arrived at the Kennedy Space Center in Florida, space agency NASA said. According to NASA, the mission will be dedicated to surveying the upper atmosphere of Mars in an effort to understand the role that the loss of atmospheric gas to space played in changing the climate of Mars. The spacecraft is scheduled to lift off in November to begin a 10-month voyage to Mars. — Agencies |
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THIS UNIVERSE When we move an object tied to a string around us, it moves in a circular motion, whereas the planets move around the Sun in an elliptical orbit. Why? When you move an object tied to a string around you, it has no other choice than to move in a circle. This is because it is constrained to stick to a path which has a constant distance around you, namely the length of the string. This length is the radius of the circle. Now take the case of a planet falling towards a star because of gravitational pull. If this planet had no other motion and the only force is the gravitational pull of the star, it will fall on to the star. On the other hand, if the planet had been wandering, or had been kicked because of a sideways pull, it will go on moving in the general direction of the star, approach it with ever increasing speed and shoot past the star, going to the other side, turn around at the closest point of approach, called the perigee, at about the time when it has maximum velocity and start climbing towards its apogee. I have used a long clumsy sentence to say that the planet will start moving in an elliptical path around the star. What I have said comes out of equations of motion which say the general solution for the orbit of a planet around a star is an ellipse. Why can’t we see an atom? Is there any way we can see it? Depends on what you call seeing. We detect and observe the interaction of atoms all the time. It is just that we have to use proper eyes. |
A warmer world with more droughts and other climate-related disasters is likely to lead a substantial increase in violent conflict between both individuals and entire societies, a major study has found. A review of 61 detailed accounts of violence has concluded that personal disputes and wider civil conflicts increase significantly with significant changes to weather patterns, such as increases in temperature and lack of rain, scientists said.
