Sunday, April 29, 2007

Aerial Archaeology

Aerial archaeology is the study of archaeological leftovers by examining them from elevation. It is one of the oldest prospecting methods. It is very productive and cheap, Aerial archaeology is frequent opinion that an aerial archaeologist is sitting in an aero plane, trying to discover archaeological sites and to take a few good photographs of them. To perform aerial archaeology you can also used satellite images, thermal images or airborne radar images. The advantages of gaining a good aerial vision of the ground had been long appreciated by archaeologists as a high viewpoint permits an enhanced appreciation of excellent details and their relationships within the wider site context. Early investigators attempted to gain bird’s eye views of sites by hot air balloons, scaffolds or cameras attached to kites. Following the invention of the aero plane and Aerial photography helps military during the First and Second World Wars, archaeologists were able to more effectively use the technique to find out and record archaeological sites.

Monday, April 23, 2007

Major ice ages

There have been at least four main ice ages in the Earth's past.

The most basic hypothesized ice age is believed to have occurred around 2.7 to 2.3 billion years ago during the early Proterozoic Age.

Main article: Snowball Earth.
The most basic well-documented ice age, and probably the most severe of the last 1 billion years, occurred from 800 to 600 million years ago and it has been recommended that it produced a Snowball Earth in which permanent sea ice extended to or very near the equator. It has been recommended that the end of this ice age was responsible for the subsequent Cambrian Explosion, though this theory is current and contentious.
A negligible ice age occurred from 460 to 430 million years ago, through the Late Ordovician Period.

Sediment records viewing the changeable sequences of glacials and interglacials during the last several million years. The present ice age began 40 million years ago with the growth of an ice sheet in Antarctica, but intensified during the Pleistocene with the spread of ice sheets in the Northern Hemisphere. Since then, the world has seen cycles of glaciations with ice sheets advancing and retreating on 40,000 and 100,000 year time scales. The last glacial period finished about 10,000 years ago.

The timing of ice ages throughout geologic history is in part restricted by the position of the continental plates on the surface of the Earth. Small changes in solar energy can tip the balance between summers in which the winter snow mass totally melts and summers in which the winter snow persists until the following winter. Due to the positions of Greenland, Antarctica, and the northern portions of Europe, Asia, and North America in Polar Regions, the Earth today is considered prone to ice age glaciations.

Proof for ice ages comes in various forms, including rock scouring and scratching, glacial moraines, drumlins, valley cutting, and the statement of till or tallies and glacial erratic. Successive glaciations tend to distort and erase the geological evidence, making it difficult to interpret. It took some time for the current theory to be worked out. Analyses of ice cores and ocean sediment cores unambiguously show the record of glacial and interglacial over the past few million years.

Thursday, April 19, 2007


The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. It acts as a variable valve which, based on its input current (BJT) or input voltage (FET), allows a precise amount of current to flow through it from the circuit's voltage supply.In essence, a transistor have three terminals. A current or voltage applied through/across two terminals controls a larger current through the other terminal and the common terminal. In analog circuits, transistors are used in amplifiers. Analog circuits comprise audio amplifiers, stabilised power supplies and radio frequency amplifiers. In digital circuits, transistors function basically as electrical switches. Digital circuits include logic gates, RAM (random access memory) and microprocessors.Transistor was also the common name in the sixties for a transistor radio, a portable radio that used transistors (rather than vacuum tubes) as its active electronic components. This is still one of the dictionary definitions of transistor.

Tuesday, April 10, 2007

Postage Stamp

A postage stamp is proof of pre-paying a fee for postal services. Usually a small paper rectangle which is attached to an cover, signifying that the person sending the letter or package has paid for delivery, it is the most popular option to using a prepaid-postage envelope.


In it he argued that it would be well again for the sender to pay the cost of delivery, rather than the receiver who could refuse the letter if they could not or did not want to pay, as occasionally happened at the time. He also argued for a uniform rate of one penny per letter, no matter where its destination. Accounting costs for the government would thus be cut; postage would no longer be charged according to how far a letter had traveled, which required each letter to have an individual entry in the Royal Mail's accounts. Chalmers' ideas were finally adopted by Parliament in August, 1839 and the General Post Office launched the Penny Post service the next year in 1840 with two prepaid-postage symbolic envelopes or wrappers: one valued at a penny and one valued at two pence.

Three months later on the first prepaid-postage stamp, known as the Penny Black was issued with the profile of Queen Victoria printed on it. Because the United Kingdom issued the first stamps, the Universal Postal Union grants it an exemption from its rule that the recognition of the issuing country must appear on a stamp in Roman script for use in international mails. Before joining the U.P.U. many countries did not do this; there are very few violations of the rule since this time, though one example is the U.S. Pilgrim Tercentenary series, on which the country designation was inadvertently excluded. Because of this the numerous early issues of China and Japan often confound new collectors unfamiliar with Oriental scripts. A stamp must also show a face value in the issuing country's currency. Some countries have issued stamps with a letter of the alphabet or designation such as "First class" for a face value. Because of the U.P.U. rules their use is restricted to domestic mail, but breach of this rule is often tolerated. Exceptions to this are the British "E" stamp and the South African "International Letter Rate" stamp.

Friday, April 06, 2007

Asian Paradise Flycatcher

The Asian Paradise Flycatcher, also known as the Common Paradise Flycatcher, is a medium-sized passerine bird. It was in the past classified with the Old World flycatcher family Muscicapidae, but the paradise flycatchers, monarch flycatchers and Australasian fantails are now usually grouped with the drongos in the family Dicruridae, which has the majority of its members in Australasia and tropical southern Asia.

The Asian glory Flycatcher breeds from Turkestan to Manchuria. It is wandering, wintering in tropical Asia. There are resident populations further south, for example in southern India and Sri Lanka, so both visiting migrants and the in the vicinity reproduction subspecies take place in these areas in winter.

This species is typically originated in thick forests and other well-wooded habitats. Three or four eggs are laid in a cup shell in a tree.

The adult male Asian Paradise Flycatcher is about 20 cm long, but the long tail streamers double this. It has a black crested head, stale joke upperparts and pale grey underparts.

By their second year, the males of the wandering Indian race T. p. paradisi begin to obtain white feathers. By the third year, the male plumage is totally white, other than the black head. Males of the sedentary Sri Lankan race T. p. ceylonensis are forever stale joke.

The female of all races resembles the stale joke male, but has a grey throat, minor peak and lacks the tail streamers.

Monday, April 02, 2007

Jet Airways

Jet Airways is an airline based in India, helping familial and worldwide routes. The airline operates over 250 flights to 44 destinations athwart the country, with the majority of flights operated from Chhatrapati Shivaji International Airport, Mumbai. It presently controls about 40% of India's aviation market.


Jet Airways was recognized on 5 May 1993 with a fleet of 4 Boeing 737-300 aircraft, with 24 daily flights helping 12 destinations.


Its 44 destinations contain most of the big cities in India. Its international destinations contain Kathmandu, Colombo, Singapore, Kuala Lumpur and London's Heathrow Airport. Jet Airways was the first personal airline of India to fly to international destinations. It was later joined by Air Sahara. The daily Delhi-London service started in October of that year.

Jet Airways and Air Sahara are the only personal airlines which survived the Indian business downward spiral of the 1990s. On January 19, 2006 Jet Airways announced that it is buying Air Sahara for $500 million. This is the biggest takeover in India's aviation history and the resulting airline will be the countries biggest.
In 2006 Jet Airways will be raising its way network from Delhi via the north Indian city of Amritsar, as it is to begin Amritsar-London and/or Amritsar-Birmingham.