Alzheimer's disease

Approximately 24 million people worldwide have dementia of which the majority (~60%) is due to Alzheimer's. Clinical signs of Alzheimer's disease are characterized by progressive cognitive deterioration, together with declining activities of daily living and by neuropsychiatric symptoms or behavioral changes.
The most striking early symptom is memory loss (amnesia), usually manifest as minor forgetfulness that becomes steadily denser with illness progression, with relative preservation of older memories. It is the most common type of dementia.
Plaques which contain misfolded peptides called amyloid beta (Aβ) are formed in the brain many years before the clinical signs of Alzheimer's are observed.
Together, these plaques and neurofibrillary tangles form the pathological hallmarks of the disease.
These features can only be discovered at autopsy and help to confirm the clinical diagnosis.
Medications can help reduce the symptoms of the disease, but they cannot change the course of the underlying pathology. The ultimate cause of Alzheimer's is unknown.
Genetic factors are clearly indicated as evidenced by dominant mutations in three different genes have been identified that account for the small number of cases of familial, early-onset AD.
For the more common form of late onset AD (LOAD), ApoE is the only clearly established susceptibility gene.
All four genes can contain mutations or variants that confer increased risk for AD, but account for only 30% of the genetic picture of AD.
These four genes have in common the fact that mutations in each lead to the excessive accumulation in the brain of Aβ, the main component of the senile plaques that litter the brains of AD patients..

Planet Pluto

Pluto, (PLOO toh), is a dwarf planet that orbits far from the sun. It shares the region of its orbit, known as the Kuiper belt, with a collection of similar icy bodies called Kuiper belt objects (KBO’s). From its discovery in 1930, people widely considered Pluto to be the ninth planet of our solar system. However, because of its small size and irregular orbit, many astronomers questioned whether Pluto should be grouped with worlds like Earth and Jupiter. Pluto seemed to share more similarities with KBO’s. In 2006, this debate led the International Astronomical Union, the recognized authority in naming heavenly objects, to formally classify Pluto as a dwarf planet. Pluto cannot be seen without a telescope.
Pluto is so far from Earth that even powerful telescopes reveal little detail of its surface. The Hubble Space Telescope gathered the light for the pictures of Pluto shown here. Image credit: NASA
Pluto is about 39 times as far from the sun as Earth is. Its average distance from the sun is about 3,647,240,000 miles (5,869,660,000 kilometers). Pluto travels around the sun in an elliptical (oval-shaped) orbit. At some point in its orbit, it comes closer to the sun than Neptune, the outermost planet. It stays inside Neptune's orbit for about 20 Earth years. This event occurs every 248 Earth years, which is about the same number of Earth years it takes Pluto to travel once around the sun. Pluto entered Neptune's orbit on Jan. 23, 1979, and remained there until Feb. 11, 1999. As it orbits the sun, Pluto spins on its axis, an imaginary line through its center. It spins around once in about six Earth days.
Astronomers know little about Pluto's size or surface conditions because it is so far from Earth. Pluto has an estimated diameter of about 1,400 miles (2,300 kilometers), less than a fifth that of Earth. Pluto's surface is one of the coldest places in our solar system. Astronomers believe the temperature on Pluto may be about –375 °F (–225 °C).
Pluto is mostly brown. The planet appears to be partly covered with frozen methane gas and to have a thin atmosphere composed mostly of methane. Because Pluto's density is low, astronomers think Pluto is mainly icy. Scientists doubt Pluto has any form of life.
In 1905, Percival Lowell, an American astronomer, found that the force of gravity of some unknown object seemed to be affecting the orbits of Neptune and Uranus. In 1915, he predicted the location of a new planet and began searching for it from his observatory in Flagstaff, Arizona. He used a telescope to photograph the area of the sky where he thought the planet would be found. He died in 1916 without finding it. In 1929, Clyde W. Tombaugh, an assistant at the Lowell Observatory, used predictions made by Lowell and other astronomers and photographed the sky with a more powerful, wide-angle telescope. In 1930, Tombaugh found Pluto's image on three photographs. The planet was named after the Roman god of the dead. The name also honors Percival Lowell, whose initials are the first two letters of Pluto.
In 1978, astronomers at the U.S. Naval Observatory substation in Flagstaff detected a satellite of Pluto. They named it Charon. This satellite has a diameter of about 750 miles (1,210 kilometers).
In 1996, astronomers published the first detailed images of Pluto's surface. The images, taken by the Hubble Space Telescope, show about 12 large bright or dark areas. The bright regions, which include polar caps, are probably frozen nitrogen. The dark areas may be methane frost that has been broken down chemically by ultraviolet radiation from the sun.
In 2005, a team of astronomers studying images from the Hubble Space Telescope discovered two previously unknown moons of Pluto. The satellites, later named Hydra and Nix, had diameters of up to 100 miles (160 kilometers) and lay well outside the orbit of Charon.
In 2006, the U.S. National Aeronautics and Space Administration (NASA) launched the New Horizons probe. The probe was expected to fly by Pluto in 2015.

Agra is a very beautiful city. The Taj Mahal Monument is one of the most beautiful and most visited attraction here.The famous Taj Mahal Monument can be found in Agra, India. For this beautiful structure alone, Agra gains a lot of visitors yearly. Tourists flock to this site just to get a glimpse of this magnificent structure that embodies perfect symmetry. No one goes back home without first having their souvenir photos taken first. The wonderful feeling of seeing this monument in actual is very priceless.Agra belongs to the prominent destinations of tourists. They have a lot of heritage monument like Fatehpur Sikri, Red Fortand and the Sikandara. This is the center of culture, the religious philosophies and art. Their religious philosophies has has very enrich mankind and human thought all over the centuries. This city has been the capital of Mughal Empire. Because of this, the place still has the pass set up that it has years before. The structures that they have represents the time of the Mughal empires. These structures are considered the finest in the world.The Agra is a town that has slow pace. They have a lot of marble works inlay, soastone that were made by the Mughal people and many more. This soapstone is made by the craftsman of Mughal. This city is famous for gold thread embroiders, carpets and shoes with made of leather.As stated earlier, the Taj Mahal is found in Agra. Taj Mahal is one of the eight wonders of the world. It has an architectural beauty that never has been surpassed. This Taj Mahal is a very beautiful and important monument that was built by Mughals. These Mughals were Muslim Rulers of India by that time. The composition of this monument was entirely white marble. It has not just an ordinary beauty but a stunning architectural beauty. This beauty had been very visible during the dawn and sunset. This seems to appear so lively in the light of the moon. Even on foggy morning, the Taj has been very beautiful from the view of the Jamuna River.This Taj Mahal was built by Emperor Shah Jahan who was a muslim emperor. He built this monument in the loving memory of his wife who was his queen during his reign. His wife's name was Mumtaz Mahal but her real name was Arjumand Banu.This was said to be a dream come true because people think that the emperor had made this monument because his wife has always wished for it. The Taj Mahal is called such because it means the Crown Palace by word. This is a mausoleum where the grave of the queen Mumtaz Mahal is housed. The people placed her grave in the lowest chamber. The grave of the emperor Shah Jahan was then placed beside her remains after a few years. The original name of the emperor was Shahab-ud-din. He was the prince Khurram before he became the emperor.The Mughal traditions state that ladies of royal familes will be given a new name on the time of their marriage or on significant events in their lives. This is the reason why the monument was named the Taj Mahal because people have always used the second name of the queen.The Taj Mahal is a very grand and majestic structure. It took over twenty two years to complete. They have employed twenty thousand employees to be able to build it. This cost roughly around thirty two million Rupees and was completed in 1648. The master architect of this project was Ustad 'Isa. This man was known to be the best Islamic architect during this time.The expert craftsmen were also hired to help in putting up this monument. These famous craftsmen were Multan, Qannauj and Lahore. The Muslim craftsmen from Shiraz, Baghdad and Bukhara have also played specialized task for the Taj Mahal Monument.

Tsunami

Tsunami, Japanese word meaning “harbor wave,” used as the scientific term for a class of abnormal sea wave that can cause catastrophic damage when it hits a coastline. Tsunamis can be generated by an undersea earthquake, an undersea landslide, the eruption of an undersea volcano, or by the force of an asteroid crashing into the ocean. The most frequent cause of tsunamis is an undersea earthquake. When the ocean floor is uplifted or offset during an earthquake, a set of waves is created similar to the concentric waves generated by an object dropped into the water. Most tsunamis originate along the Ring of Fire, a zone of volcanoes and seismic activity, 32,500 km (24,000 mi) long, which encircles the Pacific Ocean. Since 1819, about 40 tsunamis have struck the Hawaiian Islands.

A tsunami can have wavelengths, or widths (the distance between one wave crest to the next), of 100 to 200 km (60 to 120 mi), and may travel hundreds of kilometers across the deep ocean, reaching speeds of about 725 to 800 km/h (about 450 to 500 mph). A tsunami is not one wave but a series of waves. In the deep ocean, the waves may be only about half a meter (a foot or two) high. People onboard a ship passing over it would not even notice the tsunami. Upon entering shallow coastal waters, however, the waves may suddenly grow rapidly in height. When the waves reach the shore, they may be 15 m (50 ft) high or more. Tsunamis can also take the form of a very fast tide or bore, depending on the shape of the sea floor.

Tsunamis have tremendous force because of the great volume of water affected and the speed at which they travel. Just a cubic yard of water, for example, weighs about one ton. Although the tsunami slows to a speed of about 48 km/h (30 mph) as it approaches a coastline, it has a destructive force equal to millions of tons. Tsunamis are capable of obliterating coastal settlements.

Tsunamis should not be confused with storm surges, which are domes of water that rise underneath hurricanes or cyclones and cause extensive coastal flooding when the storms reach land. Storm surges are particularly devastating if they occur at high tide. A cyclone and accompanying storm surge killed an estimated 500,000 people in Bangladesh in 1970. Tsunamis are sometimes called tidal waves, but they have nothing to do with the gravitational forces that cause tides.

Global Warming

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last century.[1][A] The Intergovernmental Panel on Climate Change (IPCC) concludes that increasing greenhouse gas concentrations resulting from human activity such as fossil fuel burning and deforestation are responsible for most of the observed temperature increase since the middle of the 20th century.[1] The IPCC also concludes that natural phenomena such as solar variation and volcanoes produced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward.[2][3] These basic conclusions have been endorsed by more than 45 scientific societies and academies of science,[B] including all of the national academies of science of the major industrialized countries.[4]
Climate model projections summarized in the latest IPCC report indicate that the global surface temperature will probably rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century.[1] The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. Some other uncertainties include how warming and related changes will vary from region to region around the globe. Most studies focus on the period up to the year 2100. However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.[5][6]
An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts.[7] The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.
Political and public debate continues regarding climate change, and what actions (if any) to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.