What is Air Pollution?

Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. Air is 99.9% nitrogen, oxygen, water vapor and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals.

There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and "holes" in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment.

One type of air pollution is the release of particles into the air from burning fuel for energy. Diesel smoke is a good example of this particulate matter . The particles are very small pieces of matter measuring about 2.5 microns or about .0001 inches. This type of pollution is sometimes referred to as "black carbon" pollution. The exhaust from burning fuels in automobiles, homes, and industries is a major source of pollution in the air. Some authorities believe that even the burning of wood and charcoal in fireplaces and barbeques can release significant quanitites of soot into the air.

Another type of pollution is the release of noxious gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, forming smog and acid rain.

Pollution also needs to be considered inside our homes, offices, and schools. Some of these pollutants can be created by indoor activities such as smoking and cooking. In the United States, we spend about 80-90% of our time inside buildings, and so our exposure to harmful indoor pollutants can be serious. It is therefore important to consider both indoor and outdoor air pollution.

what is a tornado?

The word "tornado" comes from the Latin tonare, meaning "to thunder." The Spanish developed the word into tornear, to turn or twist. These are good descriptions of tornadoes, which are formed by rotating or twisting air. This is why they are also called twisters or cyclones.

A tornado is a powerful column of winds spiraling around a center of low atmospheric pressure. It looks like a large black funnel hanging down from a storm cloud. The narrow end will move over the earth, whipping back and forth like a tail.

The winds inside a tornado spiral upward and inward with a lot of speed and power. It crates an internal vacuum that then sucks up anything it passes over. When the funnel touches a structure, the fierce winds have the ability to tear it apart.

The winds inside a twister can spin around at speeds up to 500 miles an hour, but usually travels at roughly 300 miles an hour. This makes the tornado the most dangerous storm known to mankind. Because of the earth’s unique weather system, twisters rotate counterclockwise in the Northern Hemisphere and move eastward. They rotate clockwise in the Southern Hemisphere. Tornadoes also often come with hailstorms.

Many storms create harmless funnels that never touch earth. They can last from a few seconds to a few hours. Others disappear and reappear minutes later. The average tornado has a diameter of about 200 to 300 yards, and some grow large enough to spawn smaller tornadoes known as satellite tornadoes. These small offspring, about 50 yards across, can be very fierce and do lots of damage. They also tend to branch away from the parent funnel, taking separate paths across the earth.

A tornado can form very quickly, sometimes in a minute or less. It can travel across the ground at high speeds, then just as suddenly vanish. They can kill in a matter of seconds. Every year, about $500 million worth in damage is done by twisters in the United States. Most tornadoes last less than twenty minutes and travel less than 15 miles. However, superstorms sometimes occur, traveling over 100 miles before they are exhausted. Although they don’t occur very often, they are responsible for 20% of all tornado casualties.

What is a Tsunami

A tsunami is a very long-wavelength wave of water that is generated by sudden displacementof the seafloor or disruption of any body of standing water. Tsunami are sometimes called "seismic sea waves", although, as we will see, they can be generated by mechanisms other than earthquakes. Tsunami have also been called "tidal waves", but this term should not be usedbecause they are not in any way related to the tides of the Earth. Because tsunami occursuddenly, often without warning, they are extremely dangerous to coastal communities.

Physical Characteristics of Tsunami

All types of waves, including tsunami, have a wavelength, a wave height, an amplitude, a frequency or period, and a velocity.

Wave length is defined as the distance between two identical points on a wave (i.e. between wave crests or wave troughs). Normal ocean waves have wavelengths of about 100 meters. Tsunami have much longer wavelengths, usually measured in kilometers and up to 500 kilometers.

Wave height refers to the distance between the trough of the wave and the crest or peak of the wave.

Wave amplitude - refers to the height of the wave above the still water line,usually this is equal to 1/2 the wave height. Tsunami can have variable wave height and amplitude that depends on water depth as we shall see in a moment

Wave frequency or period - is the amount of time it takes for one full wavelength to pass a stationary point.

Wave velocity is the speed of the wave. Velocities of normal ocean waves are about 90 km/hr while tsunami have velocities up to 950 km/hr (about as fast as jet airplanes), and thus move much more rapidly across ocean basins. The velocity of any wave is equal to the wavelength divided by the wave period.

Tsunami are characterized as shallow-water waves. These are different from the waves most of us have observed on a the beach, which are caused by the wind blowing across the ocean's surface. Wind-generated waves usually have period (time between two successive waves) of five to twenty seconds and a wavelength of 100 to 200 meters. A tsunami can have a period in the range of ten minutes to two hours and wavelengths greater than 500 km. A wave is characterized as a shallow-water wave when the ratio of the water depth and wavelength is very small. The velocity of a shallow-water wave is also equal to the square root of the product of the acceleration of gravity and the depth of the water.

The rate at which a wave loses its energy is inversely related to its wavelength. Since a tsunami has a very large wavelength, it will lose little energy as it propagates. Thus, in very deep water, a tsunami will travel at high speeds with little loss of energy. For example, when the ocean is 6100 m deep, a tsunami will travel about 890 km/hr, and thus can travel across the Pacific Ocean in less than one day.

As a tsunami leaves the deep water of the open sea and arrives at the shallow waters near the coast, it undergoes a transformation. Since the velocity of the tsunami is also related to the water depth, as the depth of the water decreases, the velocity of the tsunami decreases.

The change of total energy of the tsunami, however, remains constant.

Furthermore, the period of the wave remains the same, and thus more water is forced between the wave crests causing the height of the wave to increase. Because of this "shoaling" effect, a tsunami that was imperceptible in deep water may grow to have wave heights of several meters or more.

If the trough of the tsunami wave reaches the coast first, this causes a phenomenon called drawdown, where it appears that sea level has dropped considerably. Drawdown is followed immediately by the crest of the wave which can catch people observing the drawdown off guard. When the crest of the wave hits, sea level rises (called run-up). Run-up is usually expressed in meters above normal high tide. Run-ups from the same tsunami can be variable because of the influence of the shapes of coastlines. One coastal area may see no damaging wave activity while in another area destructive waves can be large and violent. The flooding of an area can extend inland by 300 m or more, covering large areas of land with water and debris.

Flooding tsunami waves tend to carry loose objects and people out to sea when they retreat.

Tsunami may reach a maximum vertical height onshore above sea level, called a run-up height, of 30 meters. A notable exception is the landslide generated tsunami in Lituya Bay, Alaska in 1958 which produced a 60 meter high wave.

Because the wavelengths and velocities of tsunami are so large, the period of such waves is also large, and larger than normal ocean waves. Thus it may take several hours for successive crests to reach the shore. (For a tsunami with a wavelength of 200 km traveling at 750 km/hr, the wave period is about 16 minutes).

Thus people are not safe after the passage of the first large wave, but must wait several hours for all waves to pass. The first wave may not be the largest in the series of waves. For example, in several different recent tsunami the first, third, and fifth waves were the largest.

*Prof. Stephen A. Nelson, Natural Disasters, Tulane University.

How to prevent avian influenza

Avian Influenza is primarily a disease affecting birds. Human infections are rare. Contact with infected birds remains the main mode of transmission. The most effective way to prevent avian influenza is to avoid contact with poultry.

The World Health Organisation (WHO) continues to recommend that travellers to areas experiencing outbreaks of highly pathogenic H5N1 in poultry should avoid contact with live animal markets and poultry farms. Large amounts of the virus are known to be excreted in the droppings from infected birds. Direct contact with infected poultry, or surfaces and objects contaminated by their droppings, is considered the main route of human infection. There is no evidence that properly cooked poultry or poultry products can be a source of infection.

At present, there is no human vaccine against the H5N1 influenza virus. Available influenza vaccines do not protect against human disease caused by the H5N1 strain but against other circulating human strains (H1N1, H3N2, B). Trials of the H5N1 influenza vaccine are under way.

American ginseng/drug combination inhibits growth of breast cancer cells

In a laboratory study, combinations of standardized American ginseng extract (Panax quinquefolius) and synthetic drugs commonly used to treat breast cancer appeared to act synergistically to inhibit the growth of breast cancer cells. The study was designed to assess the possible estrogenic properties of American ginseng, the effects of American ginseng on the cancer cell cycle, and the interaction of American ginseng and standard chemotherapeutic drugs, including doxorubicin, tamoxifen, taxol, methotrexate, cytoxan, and megace, on cancer cell proliferation. The researchers selected an estrogen-sensitive cancer cell line model for use in the study. Results indicated that American ginseng had a paradoxical effect on the cancer cells, inducing the expression of the estrogen-regulated gene pS2 at a rate comparable to estrogen. Unlike estrogen, however, it did not increase the proliferative phase of the cancer cell cycle. In addition, concurrent administration of ginseng with most of the cancer drugs studied significantly inhibited cancer cell growth. The researchers concluded, "Further investigations are warranted to evaluate possible synergistic in vivo effects of the combination of [American ginseng] and cancer therapeutics." The standardized American ginseng extract used in this study, CNT2000™, was supplied by Chai-Na-Ta-Corp of Langley, British Columbia. No details about the standardization were provided.

Duda RB, Zhong Y, Navas V, et al. American ginseng and breast cancer therapeutic agents synergistically inhibit MCF-7 breast cancer cell growth. Journal of Surgical Oncology 1999; 72: 230-239

American ginseng improves glucose tolerance in diabetics and nondiabetics

A small, randomized clinical study showed that treatment with American ginseng (Panax quinquefolius) helped improve glucose tolerance in nondiabetic people as well as those with type II diabetes mellitus. For the study, 10 nondiabetic people and 9 people with type II diabetes received treatment with 3 g ginseng or placebo capsules either 40 minutes before or in combination with an oral glucose challenge. In nondiabetic participants, no difference was observed in glycemia between placebo and ginseng when the substances were administered along with glucose, but significant reductions were seen when ginseng was taken 40 minutes before the glucose challenge. However, compared with placebo, both ginseng dosage regimens improved glucose tolerance in the people with diabetes. The researchers cautioned that for nondiabetics, "to prevent unintended hypoglycemia, it may be important that the American ginseng be taken with meals." They also noted that the 3 g dose of ginseng used in their study is higher than that used in most other clinical studies, which is typically 1.5 g or less.

Vuksan V, Stevenpiper JL, Koo VYY, et al. American ginseng (Panax quinquefolius L.) reduces postprandial glycemia in nondiabetic subjects and subjects with type 2 diabetes mellitus. Archives of Internal Medicine 2000; 160: 1009-1013.

10 Most Common Mistakes Man Make with Woman

1. Being too much of a nice guy
Don't overdo the nice guy act, you can be a little rough at times. But don't be a jerk.

2. Persuading her to like you:
Buddy, this is not the movies and you are not Tom Cruise or John Travolta.

3. Constantly looking for her approval:
A woman needs a man, not a doormat. If you keep running to her to seek permission to go to the loo, don't be surprised if she dumps you, sooner or later.

4. Buying her love and affection with gifts:
Yes, women do love gifts, but they can't buy you love. To get her to fall in love with you, you need more than gifts. Get a brain.

5. Sharing your dark secrets:
Not too early on in the relationship. Before telling her about that rash, make sure she really digs you.

6. Failing to understand:
How a woman's mind works! For women's it's not just or all about the looks, it is about how they feel with a man.

7. Dressing up like a dandy:
Dress like you always do. You don't have to take out your designer clothes for a date.

8. Smelling bad:
This is one thing that is sure to put off most women. Get rid of BO.

9. Checking out other women:
Not when you are on a date, for heaven's sake! Even if Halle Berry walks by, don't take your eyes off your date. Period.

10. Taking help from others:
If you are not able to do it, do not ask your friends to help you. If you're not going to ask her out, you'll never get a date.