The recent threat to the mankind is Ebola. ebola is the disease caused by a virus Zaire ebola. many of the people were effected with Ebola, among which 90 percent people were killed within few weeks. Ebola virus are found in bats, chimpanzees of south africa. The interesting fact is, that the doctors who were treating a patient with ebola were died because of the spread of the virus by the infected person. This disease is first discovered in 1976 when two outbreaks  occured. the disease can be trasmitted by the contact of any human secretions. This disease is not transmitted through Air. It is refereed as  Ebola hemorrhagic fever. It starts with fever and continues with vomting muscle pains. It causes internal and externa bleeding which causes the death. the only way to eradicate is to avoid touchng people, washing hands, maintaining hygienic conditions.  

environment is our livelihood

Environment means the surroundings. Land, water, air, plants, animals, solid wastes and other things that are surrounding us constitute our environment. Man and environment are closely intertwined with each other, to maintain a balance or equilibrium in nature.

Different groups of people working in different areas express it in various ways. When physical scientists talk about environment they generally refer to the physical environment that comprises the three inter locking systems the Atmosphere, the Hydrosphere and the Lithosphere.

Biologists often refer to biological environment consisting of all living organisms of the Biosphere. Similarly social scientists refer to the social, cultural, economic and organizational environment.

Hence environment may be defined as "the sum of all social, cultural, economical, biological, physical and chemical factors surrounding the 'man' to give necessary protection to him."

Two types of environment we may come across. One is the natural environment of the air, water, solid wastes, noise, radiation, soil, timber, wildlife and living space etc. The second one is the man-made environment that deals with work environment, housing, technology, aesthetics, transportation, utilities, settlement, urbanization and so on.

These environmental components are considered as the resources and are mostly exploited and utilized by the men to fulfill their basic physical needs they can be considered as the fellow members of the global eco-system with which men establish emotional, intellectual, or physical relationships and these provide the basis for a sense of purpose of life to them.

Thus, man is firmly placed as an important part of the global ecosystem, which depends on him much as he depends on it. Hence, there is a close relationship between man and environment.

leadership quotes

Do not follow where the path may lead.
Go instead where there is no path and leave a trail.Harold R. McAlindon(also attributed to Emerson and others)

Leadership: The art of getting someone else to do something you want done because he wants to do it.
Dwight D. Eisenhower

There go the people.
I must follow them for I am their leader.
Alexandre Ledru-Rollin

What chance gathers she easily scatters. A great person attracts great people and knows how to hold them together.
Johann Wolfgang Von Goethe

A general is just as good or just as bad as the troops under his command make him.
General Douglas MacArthur

Men are governed only by serving them; the rule is without exception.
V. Cousin

The real leader has no need to lead--
he is content to point the way.
Henry Miller

Not the cry, but the flight of a wild duck, leads the flock to fly and follow.
Chinese Proverb

He who has never learned to obey
cannot be a good commander.
Aristotle

The ultimate measure of a man is not where he stands in moments of comfort, but where he stands at times of challenge and controversy.
Martin Luther King, Jr.(from Christian Leadership World)

Any one can hold the helm when the sea is calm.
Publilius Syrus

A leader is a dealer in hope.
Napoleon Bonaparte

nice and short story

A blind boy sat on the steps of a building with a hat by his feet. He held up a sign which said: "I am blind, please help." There were only a few coins in the hat.

A man was walking by. He took a few coins from his pocket and dropped them into the hat. He then took the sign, turned it around, and wrote some words. He put the sign back so that everyone who walked by would see the new words. 

Soon the hat began to fill up. A lot more people were giving money to the blind boy. That afternoon the man who had changed the sign came to see how things were. The boy recognized his footsteps and asked, "Were u the one who changed my sign this morning? What did u write?"

The man said, "I only wrote the truth. I said what u said but in a different way."
What he had written was: "Today is a beautiful day & I cannot see it."

Do u think the first sign & the second sign were saying the same thing? Of course both signs told people the boy was blind. But the first sign simply said the boy was blind. The second sign told people they were so lucky that they were not blind. Should we be surprised that the second sign was more effective? 

Moral of the Story:

Be thankful for what you have.

eye sight can be now reduced

eye sight can be reduced very easily by applying pure honey .yes it is real i experienced it.actually i want to become a pilot,but i have eye sight.then i got the information in a book that eye sight can be reduced by applying honey drops in you eyes.do this alternatively up to one or two months you will see a better change

funny experiments at home

cyclone at home: Take a glass and fill it with water.Now add a few drops o oil in it.pour ink half of the quantity of water in glass.Take a spoon and stir it very well.What do you observe is the ink in the glass will not be dissolve in water as it contains oil.inspite of dissolving it rotates and looks like a cyclone

we can stop the time:This a very easy and funny experiment. To tell this is not a experiment we can as it as magic take a magnet which is smaller than your thumb.now take a double sided tape,cut it in a small square and fix magnetic on it now take that tape and keep open side of your thumb.You show your friend closed side hand.And now take a wrist watch which has seconds hand place your thumb which has magnet in it.What do you observe is the seconds hand stops moving.and remove your hand to move seconds hand normally.but never tell the secret behind it             

green house gas effect

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere. As a result, the temperature there is higher than it would be if direct heating by solar radiation were the only warming mechanism.^[1][2]

This mechanism is fundamentally different from that of an actual greenhouse, which works by isolating warm air inside the structure so that heat is not lost by convection.

The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.^[3]

If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30%^[4] (or 28%^[5]) of the incoming sunlight, the planet's effective temperature (the temperature of a blackbody that would emit the same amount of radiation) is about −18 or −19 °C,^[6][7] about 33°C below the actual surface temperature of about 14 °C or 15 °C.^[8] The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.

Global warming, a recent warming of the Earth's surface and lower atmosphere,^[9] is believed to be the result of a strengthening of the greenhouse effect mostly due to human-produced increases in atmospheric greenhouse gases.^[10]

Contents  [hide] 1 Basic mechanism 2 Greenhouse gases 3 Role in climate change 4 Real greenhouses 5 Bodies other than Earth 6 Literature 7 References

Basic mechanism

The Earth receives energy from the Sun in the form UV, visible, and near IR radiation, most of which passes through the atmosphere without being absorbed. Of the total amount of energy available at the top of the atmosphere (TOA), about 50% is absorbed at the Earth's surface. Because it is warm, the surface radiates far IR thermal radiation that consists of wavelengths that are predominantly much longer than the wavelengths that were absorbed. Most of this thermal radiation is absorbed by the atmosphere and re-radiated both upwards and downwards; that radiated downwards is absorbed by the Earth's surface. This trapping of long-wavelength thermal radiation leads to a higher equilibrium temperature than if the atmosphere were absent.

This highly simplified picture of the basic mechanism needs to be qualified in a number of ways, none of which affect the fundamental process.

The solar radiation spectrum for direct light at both the top of the Earth's atmosphere and at sea level

• The incoming radiation from the Sun is mostly in the form of visible light and nearby wavelengths, largely in the range 0.2–4 μm, corresponding to the Sun's radiative temperature of 6,000 K.^[11] Almost half the radiation is in the form of "visible" light, which our eyes are adapted to use.^[12]
• About 50% of the Sun's energy is absorbed at the Earth's surface and the rest is reflected or absorbed by the atmosphere. The reflection of light back into space—largely by clouds—does not much affect the basic mechanism; this light, effectively, is lost to the system.
• The absorbed energy warms the surface. Simple presentations of the greenhouse effect, such as the idealized greenhouse model, show this heat being lost as thermal radiation. The reality is more complex: the atmosphere near the surface is largely opaque to thermal radiation (with important exceptions for "window" bands), and most heat loss from the surface is by sensible heat and latent heat transport. Radiative energy losses become increasingly important higher in the atmosphere largely because of the decreasing concentration of water vapor, an important greenhouse gas. It is more realistic to think of the greenhouse effect as applying to a "surface" in the mid-troposphere, which is effectively coupled to the surface by a lapse rate.
• Within the region where radiative effects are important the description given by the idealized greenhouse model becomes realistic: The surface of the Earth, warmed to a temperature around 255 K, radiates long-wavelength, infrared heat in the range 4–100 μm.^[11] At these wavelengths, greenhouse gases that were largely transparent to incoming solar radiation are more absorbent.^[11] Each layer of atmosphere with greenhouses gases absorbs some of the heat being radiated upwards from lower layers. To maintain its own equilibrium, it re-radiates the absorbed heat in all directions, both upwards and downwards. This results in more warmth below, while still radiating enough heat back out into deep space from the upper layers to maintain overall thermal equilibrium. Increasing the concentration of the gases increases the amount of absorption and re-radiation, and thereby further warms the layers and ultimately the surface below.^[7]
• Greenhouse gases—including most diatomic gases with two different atoms (such as carbon monoxide, CO) and all gases with three or more atoms—are able to absorb and emit infrared radiation. Though more than 99% of the dry atmosphere is IR transparent (because the main constituents—N₂, O₂, and Ar—are not able to directly absorb or emit infrared radiation), intermolecular collisions cause the energy absorbed and emitted by the greenhouse gases to be shared with the other, non-IR-active, gases.
• The simple picture assumes equilibrium. In the real world there is the diurnal cycle as well as seasonal cycles and weather. Solar heating only applies during daytime. During the night, the atmosphere cools somewhat, but not greatly, because its emissivity is low, and during the day the atmosphere warms. Diurnal temperature changes decrease with height in the atmosphere.

Greenhouse gases

Main article: Greenhouse gas

By their percentage contribution to the greenhouse effect on Earth the four major gases are:^[13][14]

• water vapor, 36–70%
• carbon dioxide, 9–26%
• methane, 4–9%
• ozone, 3–7%

The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the atmosphere.^[14]

Role in climate change

Main article: Global warming

The Keeling Curve of atmospheric CO₂ concentrations measured at Mauna Loa Observatory.

Strengthening of the greenhouse effect through human activities is known as the enhanced (or anthropogenic) greenhouse effect.^[15] This increase in radiative forcing from human activity is attributable mainly to increased atmospheric carbon dioxide levels.^[16]

CO₂ is produced by fossil fuel burning and other activities such as cement production and tropical deforestation.^[17] Measurements of CO₂from the Mauna Loa observatory show that concentrations have increased from about 313 ppm ^[18] in 1960 to about 389 ppm in 2010. The current observed amount of CO₂ exceeds the geological record maxima (~300 ppm) from ice core data.^[19] The effect of combustion-produced carbon dioxide on the global climate, a special case of the greenhouse effect first described in 1896 by Svante Arrhenius, has also been called the Callendar effect.

Because it is a greenhouse gas, elevated CO₂ levels contribute to additional absorption and emission of thermal infrared in the atmosphere, which produce net warming. According to the latest Assessment Report from the Intergovernmental Panel on Climate Change, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations".^[20]

Over the past 800,000 years,^[21] ice core data shows unambiguously that carbon dioxide has varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm.^[22] Paleoclimatologists consider variations in carbon dioxide to be a fundamental factor in controlling climate variations over this time scale.^[23][24]

Real greenhouses

A modern Greenhouse in RHS Wisley

The "greenhouse effect" is named by analogy to greenhouses. The greenhouse effect and a real greenhouse are similar in that they both limit the rate of thermal energy flowing out of the system, but the mechanisms by which heat is retained are different.^[25] A greenhouse works primarily by preventing absorbed heat from leaving the structure through convection, i.e. sensible heat transport. The greenhouse effect heats the earth because greenhouse gases absorb outgoing radiative energy and re-emit some of it back towards earth.

A greenhouse is built of any material that passes sunlight, usually glass, or plastic. It mainly heats up because the Sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature will drop considerably. It has also been demonstrated experimentally (R. W. Wood, 1909) that a "greenhouse" with a cover of rock salt (which is transparent to infra red) heats up an enclosure similarly to one with a glass cover.^[26] Thus greenhouses work primarily by preventing convective cooling.^[27][28]

In the greenhouse effect, rather than retaining (sensible) heat by physically preventing movement of the air, greenhouse gases act to warm the Earth by re-radiating some of the energy back towards the surface. This process may exist in real greenhouses, but is comparatively unimportant there.

Bodies other than Earth

In our solar system, Mars, Venus, and the moon Titan also exhibit greenhouse effects.^[29] Titan has an anti-greenhouse effect, in that its atmosphere absorbs solar radiation but is relatively transparent to infrared radiation. Pluto also exhibits behavior superficially similar to the anti-greenhouse effect.^[30][31]

A runaway greenhouse effect occurs if positive feedbacks lead to the evaporation of all greenhouse gases into the atmosphere.^[32] A runaway greenhouse effect involving carbon dioxide and water vapor is thought to have occurred on Venus.^[33]

Literature

Wikimedia Commons has media related to: Greenhouse effect

Look up greenhouse effect inWiktionary, the free dictionary.

Wikibooks has a book on the topic of Climate Change

Wikiversity has learning materials aboutTopic:Climate change

• Earth Radiation Budget, http://marine.rutgers.edu/mrs/education/class/yuri/erb.html
• Businger, Joost Alois; Fleagle, Robert Guthrie (1980). An introduction to atmospheric physics. International geophysics series (2nd ed.). San Diego: Academic. ISBN 0-12-260355-9.
• IPCC assessment reports, see http://www.ipcc.ch/
• Henderson-Sellers, Ann; McGuffie, Kendal (2005). A climate modelling primer (3rd ed.). New York: Wiley. ISBN 0-470-85750-1. "Greenhouse effect: the effect of the atmosphere in re-reradiating longwave radiation back to the surface of the Earth. It has nothing to do with glasshouses, which trap warm air at the surface."
• Idso, S.B. (1982). Carbon dioxide : friend or foe? : an inquiry into the climatic and agricultural consequences of the rapidly rising CO₂content of Earth's atmosphere. Tempe, AZ: IBR Press. OCLC 63236418. "...the phraseology is somewhat in appropriate, since CO₂does not warm the planet in a manner analogous to the way in which a greenhouse keeps its interior warm"
• Kiehl, J.T., Trenberth, K. (1997). "Earth's annual mean global energy budget". Bulletin of the American Meteorological Society 78 (2): 197–208. doi:10.1175/1520-0477(1997)078<0197:EAGMEB>2.0.CO;2.