Thirukkuralin Sirappu Amsangal

இயற்றியவர்: திருவள்ளுவர்.

                திருக்குறள் (Thirukkural) உலகப்புகழ் பெற்ற தமிழ் இலக்கியமாகும். இதனை இயற்றியவர் திருவள்ளுவர் என்று அறியப்படுபவர். இதில் 1330 குறள்கள் பத்து பத்தாக 133 அதிகாரங்களின் கீழ் தொகுக்கப் பெற்றுள்ளன. திருக்குறள் சங்க இலக்கிய வகைப்பாட்டில் பதினெண்கீழ்க்கணக்கு எனப்படும் பதினெட்டு நூல்களின் திரட்டில் இருக்கிறது. இது அடிப்படையில் ஒரு வாழ்வியல் நூல். மாந்தர்கள் தம் அகவாழ்விலும் சுமுகமாக கூடி வாழவும், புற வாழ்விலும் இன்பமுடனும் இசைவுடனும் நலமுடனும் வாழவும் தேவையான அடிப்படைப் பண்புகளை விளக்குகிறது. இந்நூல் அறம், பொருள், இன்பம் அல்லது காமம் என்னும் முப்பெரும் பிரிவுகளாய் (முப்பால்) பிரித்தும் அழகுடன் இணைத்தும் கோர்த்தும் விளக்குகிறது.

                    வாழ்வியலின் எல்லா அங்கங்களையும் திருக்குறள் கூறுவதால், அதைச் சிறப்பித்துப் பல பெயர்களால் அழைப்பர்: திருக்குறள், முப்பால், உத்தரவேதம், தெய்வநூல், பொதுமறை, பொய்யாமொழி, வாயுறை வாழ்த்து, தமிழ் மறை, திருவள்ளுவம் என்ற பெயர்கள் அதற்குரியவை. கருத்துக்களை இன, மொழி, பாலின பேதங்களின்றி காலம் கடந்தும் பொருந்துவது போல் கூறி உள்ளதால் இந்நூல் "உலகப் பொது மறை" என்றும் அழைக்கப்படுகிறது

                    

History of E-mail

• Electronic mail, most commonly called email or e-mail since around 1993,^[2] is a method of exchanging digital messages from an author to one or more recipients. Email operates across the Internet or other computer networks.
• Some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need connect only briefly, typically to a mail server, for as long as it takes to send or receive messages.
• Historically, the term electronic mail was used generically for any electronic document transmission. For example, several writers in the early 1970s used the term to describe fax document transmission.^[3][4] As a result, it is difficult to find the first citation for the use of the term with the more specific meaning it has today.
• An Internet email message consists of three components, the message envelope, the message header, and the message body. The message header contains control information, including, minimally, an originator's email address and one or more recipient addresses. Usually descriptive information is also added, such as a subject header field and a message submission date/time stamp.

History of Internet

Introduction

By definition the Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol. But, how did it come to be this technology that is so popular and so widely used around the world? Was it always so large and extensive, filled with information about just about anything you could possibly think of accessible from almost anywhere, anytime? The answer is no and its important to understand where it all came from to understand how to utilize it to its fullest potential now.

Creation

The Internet origin comes from a military project. The Semi Automatic Ground Environment (SAGE) program consisted of networked country-wide radar systems together for the first time. This was created around 1958 as part of an attempt to regain the lead in technology from the Soviet Union who had recently launched Sputnik. J.C.R. Licklider was selected to head the committee which controlled the SAGE project. He envisioned universal networking as a unifying human revolution.

Growth

Although the basic applications and guidelines that make the Internet possible had existed for almost a decade, the network did not gain public face until the 1990s. On August 6, 1991, CERN, which straddles the border between France and Switzerland, publicized the new World Wide Web project. The web was invented by English scientist Tim Berners-Lee in 1989.

WWW Logo

An early popular web browser was Viola WWW. It was eventually replaced in popularity by the Mosaic web browser. By 1996 usage of the word “Internet” had become commonplace, and consequently, so had its use as a reference to the World Wide Web. Over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks have remained seperate).

Today’s Internet

Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contrracts and technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet has severely matured since its birth many years ago. Today almost 1.5 billion people use the Internet. That’s almost a quarter of the entire world (a lot of people).

The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet Protocol (IP) addresses, and protocol port and parameter numbers. A globally unified namespace is essential for the Internet to function. Because the Internet is a distributed network comprising many volunatirly interconnected networks, the Internet, as such, has no governing body.

Air Pollution

Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing diseases, death to humans, damage to other living organisms such as animals and food crops, or the natural or built environment. Air pollution may come from anthropogenic or natural sources. The atmosphere is a complex natural gaseous system that is essential to support life on planet Earth.

Major primary pollutants produced by human activity include:

• Sulfur oxides (SO_x) - particularly sulfur dioxide, a chemical compound with the formula SO₂. SO₂ is produced by volcanoes and in various industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide. Further oxidation of SO₂, usually in the presence of a catalyst such as NO₂, forms H₂SO₄, and thus acid rain.[2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.
• Nitrogen oxides (NO_x) - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion, and are also produced during thunderstorms by electric discharge. They can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a chemical compound with the formula NO₂. It is one of several nitrogen oxides. One of the most prominent air pollutants, this reddish-brown toxic gas has a characteristic sharp, biting odor.
• Carbon monoxide (CO) - CO is a colorless, odorless, toxic yet non-irritating gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
• Volatile organic compounds (VOC)
• Particulates
• Persistent free radicals
• Toxic metals, such as lead and mercury, especially their compounds.
• Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from products are currently banned from use. These are gases which are released from air conditioners, refrigerators, aerosol sprays, etc. CFC's on being released into the air rises to stratosphere. Here they come in contact with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface. This can lead to skin cancer, disease to eye and can even cause damage to plants.
• Ammonia (NH₃)
• Odours — such as from garbage, sewage, and industrial processes
• Radioactive pollutants - produced by nuclear explosions, nuclear events, war explosives, and natural processes such as the radioactive decay of radon.

Water Pollution

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.

Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, but also to the natural biological communities.

Point sources :

Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes. The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.

Non-point sources:

Nonpoint source pollution refers to diffuse contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from "sheet flow" over an agricultural field or a forest are also cited as examples of NPS pollution.

Groundwater pollution

Interactions between groundwater and surface water are complex. Consequently, groundwater pollution, also referred to as groundwater contamination, is not as easily classified as surface water pollution.^[8] By its very nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant. A spill or ongoing release of chemical or radionuclide contaminants into soil (located away from a surface water body) may not create point or non-point source pollution but can contaminate the aquifer below, creating a toxic plume. The movement of the plume, called a plume front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater contamination may focus on soil characteristics and site geology, hydrogeology, hydrology, and the nature of the contaminants.

Psychologist - Sigmund Freud

       

         

                 Sigmund Freud  born Sigismund Schlomo Freud; 6 May 1856 – 23 September 1939) was an Austrian neurologist and the father of psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient and a psychoanalyst. Freud was born to Galician Jewish parents in the Moravian town of Freiberg, in the Austro-Hungarian Empire. He qualified as a doctor of medicine in 1881 at the University of Vienna, Upon completing his habilitation in 1885, he was appointed a docent in neuropathology and became an affiliated professor in 1902.^[6] Freud lived and worked in Vienna, having set up his clinical practice there in 1886. In 1938 he left Austria to escape the Nazis and died in exile in the United Kingdom the following year.

Psychologist - F.B.Skinner

       

• Burrhus Frederic Skinner (March 20, 1904 – August 18, 1990), commonly known as B. F. Skinner, was an American psychologist, behaviorist, author, inventor, and social philosopher. He was the Edgar Pierce Professor of Psychology at Harvard University from 1958 until his retirement in 1974.
• Skinner was born in Susquehanna, Pennsylvania, to Grace and William Skinner. His father was a lawyer. He became an atheist after a Christian teacher tried to assuage his fear of the hell that his grandmother described.^[18] His brother Edward, two and a half years younger, died at age sixteen of a cerebral hemorrhage. He attended Hamilton College in New York with the intention of becoming a writer
• Skinner received a Ph.D. from Harvard in 1931, and remained there as a researcher until 1936. He then taught at the University of Minnesota at Minneapolis and later at Indiana University, where he was chair of the psychology department from 1946–1947, before returning to Harvard as a tenured professor in 1948. He remained at Harvard for the rest of his life. In 1973 Skinner was one of the signers of the Humanist Manifesto II.

• In 1936, Skinner married Yvonne (Eve) Blue. The couple had two daughters, Julie (m. Vargas) and Deborah (m. Buzan).^[22][23] He died of leukemia on August 18, 1990, and is buried in Mount Auburn Cemetery, Cambridge, Massachusetts. Skinner continued to write and work until just before his death. Just a few days before his death, he was given a lifetime achievement award by the American Psychological Association and delivered a 15-minute address concerning his work