How Social Is Social Networking?

Written by Science Knowledge on 8:00 AM

With more than 220 million people worldwide using online networks such as Facebook and MySpace, the capacity to interact with people around the world has rapidly expanded. Such developments open up new ways to build social networks. Simply by going online, we can find out what our friends are up to, go through their photo albums and know what is on their minds—even when they are on the other side of the planet. Do such virtual social networks contribute to better health the way real networks do? Some speculate that Facebook is particularly valuable for those who are less mobile (such as older adults or the disabled) and therefore represents an excellent way to avoid social isolation. There are also warnings, however, that in some cases, rather than reducing social isolation, tools such as Facebook could actually add to it. In a survey of 184 MySpace users, media researchers Rob Nyland, Raquel Marvez and Jason Beck of Brigham Young University found that the most frequent users reported being less involved in the communities around them than the least frequent users. This assessment suggests that virtual-world networking can become a substitute for real-world engagement.

Source of Information :  Scientific American Mind September-October 2009

How to Heal a Smoker’s Lungs

Written by Science Knowledge on 8:00 AM

Your lungs have a nearly miraculous ability to heal themselves. Although longtime smokers will always have an increased risk of lung cancer, kicking the habit brings immediate health benefits. Here are some benefits the average smoker can expect from quitting:

• After 8 smoke-free hours, your blood’s carbon-monoxide and oxygen levels return to normal. This change can reduce fatigue and headaches, and increase your ability to exercise.

• After 1 smoke-free day, your chance of having a heart attack has already declined.

• After 2 or 3 smoke-free weeks, your lung function improves by nearly a third.

• After several smoke-free months, new and healthy cilia (the tiny lung-cleaning hairs) begin to grow, increasing your ability to clean your airways and prevent infection.

• After 1 smoke-free year, your risk of heart disease is half that of a continuing smoker.

Source of Information :  Oreilly - Your Body Missing Manual 

The Contents of Cigarette Smoke

Written by Science Knowledge on 8:00 AM

The swiftest and most effective way to damage them—by inhaling generous quantities of toxic cigarette smoke. While anyone born in the era of color television already knows that cigarettes are poison in a stick, you may not know exactly how they damage your lungs.

It turns out that there is no single answer. Although it’s tempting to talk about cigarette smoke as though it’s a single thing, it’s actually a lethal brew of more than 4,000 lung-scarring chemicals, with nearly 100 known carcinogens (cancer-causing agents) in the mix. The following figure highlights some of the nasty substances you’ll encounter in cigarette smoke, and links them to the industrial products they’re more often associated with.


While cigarette smoke is hard on your lungs, its most popular ingredient— nicotine—is a disaster for the rest of your body. It’s particularly hard on your heart, as it increases your heart rate while constricting your arteries, leading to higher blood pressure and hardening of the arteries. That’s why smoking is so tightly associated with heart disease. The brutal truth is this: Every cigarette you smoke inches you closer to a coronary disaster.

Because human lungs are somewhat overbuilt with capacity to spare, smokers don’t suffer the most damaging effects of cigarette smoke for some time. However, it doesn’t take many packs of puffing to coat the lungs with a rich assortment of tars. If you’re a regular smoker, you’ll have no trouble picking out your lungs in the picture below, which is featured on cigarette warning labels in several countries.

Incidentally, even though the average cigarette contains about 10 milligrams of nicotine, the most a smoker can get from burning it is a couple of milligrams. This is rather fortunate—if you could inject all the nicotine from a pack of cigarettes directly into your veins, you’d be dead in a matter of minutes.

Source of Information :  Oreilly - Your Body Missing Manual

The Riddle of Asthma

Written by Science Knowledge on 8:00 AM

In the modern world of cigarettes, automobiles, and heavy industry, it seems hardly surprising that people face increasing rates of lung diseases. However, it’s surprisingly difficult to nail down the cause of asthma—a chronic condition that causes sudden, unexpected narrowing in the airways of the lungs.

Contrary to what you might think, asthma isn’t caused by toxins in the air, but from your body’s overactive response—often, to otherwise minor irritants like dust, mold, and animal dander. During a severe asthma flare-up, the muscle tissue that lines the airways in your lungs can become so swollen that it chokes off your air supply.

The mystery of asthma is why it’s so common in the rich, industrialized countries of the Western world. The reason remains elusive. Some suggest that it’s a side effect of modern living in tightly closed spaces (and, by extension, the build-up of indoor air pollutants). Other researchers support the hygiene hypothesis, which argues that our clean living habits limit our exposure to infection and allergens early in life. Current research is contradictory—some studies suggest that early exposure to allergens can trigger lifelong asthma, while others point to lower asthma rates in environments filled with germs and irritants (daycare centers, families with many children, crowded living spaces, and so on).

Whatever the case, if you experience symptoms of asthma, such as occasional trouble breathing or a nagging shortness of breath, head to your doctor for a lung-function test. Even if your asthma isn’t severe enough to cut off your oxygen supply, the prolonged inflammation can gradually damage your lungs if you don’t manage your asthma with medication. (And no, asthma inhalers cannot cause obesity, even if they contain steroids.
They act directly on the lungs to expand air passageways or reduce inflammation.)

If you have asthma, you may be able to reduce your symptoms by controlling house dust and indoor air pollutants. The key is to identify your personal asthma triggers and work to reduce them.

Source of Information :  Oreilly - Your Body Missing Manual

Second-Rate Cleaning

Written by Science Knowledge on 8:00 AM

Some of the practices that people take to improve indoor air quality don’t have the effect you might expect. Here are some examples:

• Air cleaners. Air cleaners can trap indoor air pollutants, but many don’t work that well, and some emit extra ozone that can aggravate asthma. If you plan to buy an air cleaner, check the reviews from a reliable source like Consumer Reports (www.consumerreports.org). And remember that air cleaners have limitations— for example, a good one can remove particles from nearby air, but it can’t purify the whole house. (In fact, because of the way that extremely light PM2.5 particles drift through the air, an air cleaner might not be able to keep even a single room particle-free.)

• Vacuuming and dusting. These activities are keenly important to prevent excessive dust from building up in your home. However, both practices disturb dust and send particles into the air, which means that air quality may actually decrease immediately after a thorough cleaning. To reduce this effect, dust with a damp rag or an electrostatic cloth. You can also use a vacuum that has a built-in HEPA filter, which traps fine particles that would ordinarily be blown back into your house as part of the vacuum’s exhaust. (However, most vacuums are so poorly sealed that plenty of dust can escape, no matter what type of filter they use.)

• Air fresheners. Air “freshening” is an odd idea, with roughly the same scientific underpinnings as palm reading. Many air fresheners simply use aromas to mask offensive smells, although some include a nose-numbing chemical that makes it more difficult for you to smell anything, good or bad. Along with these dubious ingredients, air fresheners release several chemicals that are linked to lung irritation and (in high concentrations) to lung damage.

Sourceo of Information :  Oreilly - Your Body Missing Manual

Activist for the Brazilian Rain Forest

Written by Science Knowledge on 8:00 AM

Chico Mendes was born into extreme poverty in 1944 in the Acre state of western Brazil. Mendes’s people earned their living as seringeiros, or rubber tappers, workers who gather rubber from the forest’s seringeira trees owned by private owners. After World War II ended in 1945, the need for massive amounts of rubber slowed and rubber prices plunged. Landowners forced the seringeiros to sell their harvest for pennies. At the same time, ranchers squeezed the villagers into smaller pieces of viable land by slashing and burning the forests for conversion to cattle ranches. Stephan Schwartzman of the Environmental Defense Fund said, “For their part, the rubber tappers had no inkling that the forest had values and meanings in the outside world, beyond its rubber and Brazil nuts.” Within a decade of the conversion from rubber production to ranches, almost half of the rubber tapper communities died from malnutrition or lack of medical care.

Chico Mendes watched the smoke fill his homeland’s sky year after year. Into the 1970s, ancient forests burned and new ranches and farms took their place. Swindlers with counterfeit deeds took land from the few fortunate tappers who had owned their property for generations. Tappers who refused to sign over their land were killed at the hands of the scam artists. Mendes’s frustration grew as he watched his people fall deeper into trouble. “Don’t you sign anything,” he urged. “This land is ours. When you change it into money, you are losing the possibility of surviving. Land is life!” Still, the land burned, rain filled pools in the rutted ground and mosquitoes bred; malaria soon plagued the already suffering villages.

Between 1980 and 1983, a gold rush hit Brazil and highways carved through the remaining forests. Miners refined the gold with mercury, and tons of this metal began entering the ecosystem, as well as the native people’s bodies. Chico Mendes had few political skills but nevertheless led a workers’ union and fought on behalf of his people against illegal logging, the poisoning of forest ecosystems, and conditions that led to the villagers’ illness and threatened livelihoods. He taught them the value of the intact forest and at the same time informed environmentalists in other countries about the rubber tappers, a culture that most of the world never knew existed. Mendes persevered in alerting the world to the devastation that the Brazilian government and businesses had done to the Amazon Basin. International environmental groups listened; British film director Adrian Cowell released The Decade of Destruction, filmed in the Amazon, to show the world how the forests were being annihilated.

Mendes and other natives of the Amazon advocated the sensible use of tropical forests.
They tried to convince leaders that part of the forests could be conserved even while industries claimed other portions. For a half-century the seringeiros and ranchers continued a fierce battle over how the forests were to be used. Through the 1980s Mendes rallied the seringeiros into a national organization, found people in government willing to accept the idea of conservation, and helped environmentalists understand that the Brazilian forests had become an environmental emergency. The ranchers, however, did not easily retire from the forests. At the close of 1988, a rancher and his son shot Mendes to death at his home in the town where he had been born. After his death, the Brazilian government set up extractive reserves, or reserva extratìvìstas, which were forest preserves that Mendes had long advocated. The reserves now protect the seringeiros’ culture and the forest and its ecosystems. Schwartzman said, “What I wanted them [the press, policy makers, and the public] to know was that environmentalism in the Amazon . . . was what Chico was doing; that contrary to the received wisdom and common sense of the time, there were people in the forest interested in alternatives for the future—theirs and that of the forest.” Chico Mendes’s work may provide a lesson for the present and the future; local communities might hold the greatest power of anyone to save forests that are also part of their culture.

Source of Information : Green Technology Conservation Protecting Our Plant Resources

Secondary Causes of Tropical Forest Loss

Written by Science Knowledge on 8:00 AM

Secondary causes of tropical deforestation relate to the activities that have immediate negative effects on forests. The major secondary causes are the following:
• logging and logging roads
• cattle ranching
• cash crops, small-scale cultivation, and fuel wood
• mining and oil drilling
• large dams
• tourism
• new roadways

These causes can be grouped in various ways. For instance, logging roads create much the same problem as public highways by removing trees, causing erosion, and fragmenting habitat, while cattle ranching resembles mining because it requires large tracts of cleared forest.

The upheaval in the Amazon Basin provides an example of how human activities kill a forest over time. In the first phase, logging operations remove the best timber from a region, after which timber companies sell the land to cattle ranchers for their animals to graze, beginning the second phase of the land’s use. Ranchers may leave a few trees standing for shade, but after the land has been overgrazed, the ranches move to other places and families buy the land at discounted prices. These families cultivate small gardens and perhaps cut down more trees for cash crops or fuel and hunt the native animals. Eventually, the small farms deplete the nutrients from the soil so that it supports little new plant growth. The farmers move on to cleared land they can cultivate or they remove more forest. Meanwhile, other parts of the forest disappear as mining operations and oil drilling companies burn the already damaged patches of forest because burning is easier and quicker than cutting and hauling out the logs. The succession of human activities in the Amazon Basin described above is unsustainable. After a few decades, maybe less, the forested land turns into a bleak landscape that cannot support substantial human, animal, or plant life. The results of such actions are detailed in the sidebar “Chico Mendes—Activist for the Brazilian Forest.”

Ranchers and large farms have learned to reduce soil degradation by clearing the forest in a method called slash and burn. Slash and burn is a process of cutting down large tracts of forest, letting the downed trees dry, then burning them in place to release nutrients into the soil. Soils in tropical forests tend to be nutrient-poor due to the dense vegetation they support. Slash-and-burn methods fortify the soil for grazing or agriculture, but eventually the added nutrients also diminish and the ranches and farms move to another part of the forest to begin the process again. This constant using up of land and moving on to healthier sites is called shifting cultivation. Abandoned land that has been treated this way can again support a healthy mixture of growth through ecological succession in the succeeding decades. By the time the vegetation has returned, however, the shifting cultivation may also return as it progresses through a region.

Source of Information : Green Technology Conservation Protecting Our Plant Resources

Primary Causes of Tropical Forest Loss

Written by Science Knowledge on 8:00 AM

Deforestation of the world’s tropical forests today arises from a mix of primary and secondary causes that often relate to one another. Primary causes, also called basic causes, refer to general conditions within a region’s economics and politics that lead to deforestation. Secondary causes exert more specific, direct actions on trees.

The underlying factors of tropical forest loss connect to local population lifestyles. Therefore, primary causes of tropical deforestation may be different from one continent to the next. In general, however, tropical forest degradation comes from the following primary causes:

• poverty
• overpopulation
• historical factors
• government policies
• exports to the international market

Poverty and overpopulation throughout the world force people to deforest their land; consequently plant and animal biodiversity declines, pollution increases, and climate change upsets ecosystems. Regional history also puts pressure on forested lands, especially in relation to the region’s poverty levels. Tropical forests exist mostly in developing countries, other than the forests of Hawaii and Australia. The history of these developing countries include a period of colonialism in which Great Britain, France, Spain, or Portugal took land away from native people who had managed it for generations. Over time, colonial management of the land’s resources tended to exploit those resources more than private owners would likely exploit their own land.

Financially poor countries additionally hold large international debt— money owed to other countries. In order to repay debt with high interest rates, developing countries may be tempted to harvest their natural resources for income. Government policies on debt repayment, natural resource management, and exports contribute to degradation of tropical forests. Exports help to pay off debt, but there exists another reason why developing countries have high amounts of exports: overconsumption in the industrialized world. High export levels from tropical regions may be attributed to the following four factors: overconsumption, excess waste, rampant development, and specialized markets in tropical woods, plants, birds, animals, and minerals. This problem has been described in a variety of ways; one term for the problem is the throwaway society. The International Food Policy Research Institute has gathered data on the world’s resources relative to world population, and many environmental scientists have summed up the results with the following phrase: “Twenty percent of the world’s population is using 80 percent of the world’s resources.” Said another way, consumerism threatens forests.

Source of Information : Green Technology Conservation Protecting Our Plant Resources

Consequence s of Deforestation

Written by Science Knowledge on 8:00 AM

As the world’s forested area contracts, the carbon-storage capacity of the planet also decreases. Between 1990 and 2005, for example, the planet’s carbon-storage capacity declined because more than 5 percent of forests disappeared during that time. By the end of 2005, the Coalition for Rainforest Nations proposed that nations be paid to leave their forests standing because the worth of the stored carbon exceeded the worth of timber from the same trees. Kevin Conrad, a resident of Papua New Guinea (where forests are critically threatened), spoke to the United Nations in 2007 on the topic of deforestation, emissions, and global warming. “I think collectively we as humanity have become more mature in this climate battle, and we understood collectively that we’ve got to turn off all the emission sources in order to win,” Conrad said. “The climate doesn’t know whether it came from a factory or from Papua New Guinea’s deforestation. If we can deliver sustainable revenues to communities living in rural areas of tropical countries that are deforesting simply to exist, then we have sort of a win-win proposition.” Halting deforestation may be the cheapest way to slow global warming.

In 2007 the U.S. government’s Climate Change Science Program released “The North American Carbon Budget and Implications for the Global Carbon Cycle” report, which concluded that the remaining North American forests could no longer remove the amount of carbon emissions produced each year. According to the report, the North American continent accounts for 27 percent of all carbon dioxide emissions in the world, and the disparity between emissions and forests’ capacity to reduce the carbon is getting larger. The report’s authors stated, “Carbon absorption by vegetation, primarily in the form of forest growth, is expected to decline as maturing forests grow more slowly and take up less carbon dioxide from the atmosphere.” Christopher B. Field of the Carnegie Institution’s Department of Global Ecology added, “By burning fossil fuel and clearing forests, human beings have significantly altered the global carbon cycle.”

People cannot ignore the connections that nature has established between forests, the cycling of elements, and the planet’s climate. People in forested regions of the world that are also beset by poverty need compensation if they agree to save trees. Even making deforestation illegal may not completely solve the problem. Desperate loggers may leave their land alone but sneak into other areas to continue harvesting wood. Rachmat Witoelar, Indonesia’s Minister of Environment, told the Associated Press in 2007 that heavily forested countries such as his own, Brazil, and Costa Rica must receive compensation for avoiding the deforestation of their lands, or else any plan to slow carbon emissions would not work. “Our view is that we can combat climate change by maintaining the health of our forests and for that we need funding. This is a matter of justice.” Carbon payments to farmers might need official monitoring to ensure that farmers who receive payments refrain from logging forests anyway. In the deep Amazon and Congo basins, monitoring would not be an easy matter, and this highlights the challenges that come with protecting the forest biome.

Source of Information : Green Technology Conservation Protecting Our Plant Resources

Pollution and Pests

Written by Science Knowledge on 6:00 AM

Four types of pollution damage forests: acid rain, other air pollution, ozone, and runoff containing excess nitrogen fertilizers. Acid rain consists of industrial emissions containing sulfur dioxides and nitrogen oxides from fossil fuel combustion. In addition to rain, fog, snow, smog, dirt, dust, and smoke carry these compounds; all of these materials can be grouped into the general category of acid rain. Acid rain harms leaves and also makes soils more acidic. Acidic soils display different chemistry than normal soils and this affects nutrient uptake by roots. Acidification of soil also leads to a leaching of nutrients with rainwater. As a result, areas in the soil undergo eutrophication, which is the depletion of oxygen by microbes due to a sudden influx of nutrients, often nitrogen or phosphorus compounds.

Particles carried in smoke and smog change ecosystems indirectly by decreasing rainfall, and they may injure lichens, mosses, and insects in particular. The meteorologist Daniel Rosenfeld of the Hebrew University of Jerusalem explained the process to Cable News Network in 2000: “The smoke and pollution particles, when going into the clouds, distribute water into many small droplets. They are so small that they are very slow in combining into raindrops and other icy precipitation particles.” The consequence is lowered rainfall or even drought.

Trees behave in the same way as humans when they become vulnerable due to aging, poor nutrient supply, or a stress such as dehydration: They become more susceptible to injury. Climate change makes trees vulnerability to infection in two ways: first, by putting physical stress on trees that increases the likelihood of infection, and second, by expanding the normal range of pests, including invasive species. With global warming, the range of many tree pests and pathogens will grow larger and affect trees that had previously been free of disease. Infection then attacks trees already stressed by environmental changes. Pests have another advantage over trees: They can adapt to changing environmental conditions faster than trees.

A greater proportion of stressed trees also gives invasive plants an opening into the forest habitat. These invaders may be nonnative trees, but they are also likely to be plants, insects, microbes, or animals. Not all invasive species kill ecosystems, but many do, and these invaders can take over a forest in a matter of days.

Source of Information : Green Technology Conservation Protecting Our Plant Resources


About Me

In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.


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