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#51 Re: Jai Ganesh's Puzzles » Doc, Doc! » 2025-07-13 16:44:21

Hi,

#2410. What does the medical term Dissociative identity disorder mean?

#58 Re: Jai Ganesh's Puzzles » Doc, Doc! » 2025-07-11 17:36:49

Hi,

#2409. What does the medical term Purgative mean?

#62 Dark Discussions at Cafe Infinity » Clay Quotes - I » 2025-07-10 22:44:53

Jai Ganesh
Replies: 0

Clay Quotes -I

1. No man ever wetted clay and then left it, as if there would be bricks by chance and fortune. - Plutarch

2. The whole earth is the tomb of heroic men and their story is not given only on stone over their clay but abides everywhere without visible symbol woven into the stuff of other men's lives. - Pericles

3. Never put your money against Cassius Clay, for you will never have a lucky day. - Muhammad Ali

4. Last four months were great for me, was probably one of the best four months of my career, playing unbelievable in the clay court season. -
Rafael Nadal

5. I have always been an old-line Henry Clay Whig. - Abraham Lincoln

6. I think I am a complete player. I can play well on all the surfaces. For me, the clay might be easiest, but I am not a specialist on clay. - Rafael Nadal

7. Cassius Clay is a name that white people gave to my slave master. Now that I am free, that I don't belong anymore to anyone, that I'm not a slave anymore, I gave back their white name, and I chose a beautiful African one. - Muhammad Ali

8. You know growing up in Sweden meant we had a lot of rain when we played tennis. We were taught on clay courts but because of the weather, we had to go indoors a lot. - Bjorn Borg.

#63 Re: Help Me ! » LaTeX - A Crash Course » 2025-07-10 22:14:12

James Stirling Approximation or Stirling Approximation

n! \approx \sqrt{{2\pi}n}\left(\dfrac{n}{e}\right)^{n}

gives

where

\text{ n is the number and e is the natural logarithm base }

gives

and

\pi \text { is the Ratio of Circumference of a circle to its diameter }

gives

.

#64 Jokes » Dance Jokes - VIII » 2025-07-10 22:06:51

Jai Ganesh
Replies: 0

Q: What sort of dance does a plumber do?
A: A tap dance!
* * *
Q: How do ballroom rumors spread?
A: Through the GRAPEVINE.
* * *
Q: Where do butchers dance?
A:  At the meatball!
* * *
Q: How does a witch-doctor ask a girl to dance?
A: Voodoo like to dance with me?
* * *
Q: Where can you dance in California?
A: San Frandisco.
* * *

#65 Re: Help Me ! » LaTeX - A Crash Course » 2025-07-10 19:02:14

Please see page 1 to page 13 in LaTeX coding specifically from page 8 to page 13

#66 Science HQ » Manganese » 2025-07-10 17:25:40

Jai Ganesh
Replies: 0

Manganese

Gist

Manganese (Mn) is a chemical element, a silvery-gray, hard, and brittle transition metal with atomic number 25. It's essential for various industrial applications, particularly in steelmaking, and is also a vital trace element for both plants and animals, including humans.

It is mainly used in alloys, such as steel. Steel contains about 1% manganese, to increase the strength and also improve workability and resistance to wear. Manganese steel contains about 13% manganese. This is extremely strong and is used for railway tracks, safes, rifle barrels and prison bars.

Summary

Manganese is a chemical element; it has symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent, as a rubber additive, and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide.

Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes.

Manganese is commonly found in laboratories in the form of the deep violet salt potassium permanganate where it is used as an oxidizer. Potassium permanganate is also used as a biocide in water treatment.

It occurs at the active sites in some enzymes. Of particular interest is the use of a Mn–O cluster, the oxygen-evolving complex, in the production of oxygen by plants.

Details

Manganese (Mn), chemical element, one of the silvery white, hard, brittle metals of Group 7 (VIIb) of the periodic table. It was recognized as an element in 1774 by the Swedish chemist Carl Wilhelm Scheele while working with the mineral pyrolusite and was isolated the same year by his associate, Johan Gottlieb Gahn. Although it is rarely used in pure form, manganese is essential to steelmaking.

Element Properties

atomic number  :  25
atomic weigh  :  54.938
melting point  :  1,246 °C (2,275 °F)
boiling point  :  2,062 °C (3,744 °F)
density  :  7.21–7.44 gram/{cm}^{3} at 20 °C (68 °F)
oxidation states  :  +2, +3, +4, +5, +6, +7

Occurrence, uses, and properties

Manganese combined with other elements is widely distributed in Earth’s crust. Manganese is second only to iron among the transition elements in its abundance in Earth’s crust; it is roughly similar to iron in its physical and chemical properties but is harder and more brittle. It occurs in a number of substantial deposits, of which the most important ores (which are mainly oxides) consist primarily of manganese dioxide (MnO2) in the form of pyrolusite, romanechite, and wad. Manganese is essential to plant growth and is involved in the assimilation of nitrates in green plants and algae. It is an essential trace element in higher animals, in which it participates in the action of many enzymes. Lack of manganese causes testicular atrophy. An excess of this element in plants and animals is toxic.

Manganese ores are primarily produced by Australia, South Africa, China, Gabon, and Brazil. Large areas of the ocean floor are covered with manganese nodules, also called polymetallic nodules, concretions of manganese with some iron, silicon, and aluminum. The amount of manganese in the nodules is estimated to be much more than that in land reserves.

Most of the manganese produced is used in the form of ferromanganese and silicomanganese alloys for iron and steel manufacture. Manganese ores containing iron oxides are first reduced in blast furnaces or electric furnaces with carbon to yield ferromanganese, which in turn is used in steelmaking. Adding manganese, which has a greater affinity for sulfur than does iron, converts the low-melting iron sulfide in steel to high-melting manganese sulfide. Produced without manganese, steel breaks up when hot-rolled or forged. Steels generally contain less than 1 percent manganese. Manganese steel is used for very rugged service; containing 11–14 percent manganese, it provides a hard, wear-resistant, and self-renewing surface over a tough unbreakable core. Pure manganese produced electrolytically is used mostly in the preparation of nonferrous alloys of copper, aluminum, magnesium, and nickel and in the production of high-purity chemicals. Practically all commercial alloys of aluminum and magnesium contain manganese to improve corrosion resistance and mechanical properties. Aluminum cans contain about 1.5 percent manganese.

All natural manganese is the stable isotope manganese-55. It exists in four allotropic modifications; the complex cubic structure of the so-called alpha phase is the form stable at ordinary temperatures. Manganese somewhat resembles iron in general chemical activity. The metal oxidizes superficially in air and rusts in moist air. It burns in air or oxygen at elevated temperatures, as does iron; decomposes water slowly when cold and rapidly on heating; and dissolves readily in dilute mineral acids with hydrogen evolution and the formation of the corresponding salts in the +2 oxidation state.

Manganese is quite electropositive, dissolving very readily in dilute nonoxidizing acids. Although relatively unreactive toward nonmetals at room temperature, it reacts with many at elevated temperatures. Thus, manganese burns in chlorine to give manganese(II) chloride (MnCl2), reacts with fluorine to give manganese(II) fluoride (MnF2) and manganese(III) fluoride (MnF3), burns in nitrogen at about 1,200 °C (2,200 °F) to give manganese(II) nitride (Mn3N2), and burns in oxygen to give manganese(II,III) oxide (Mn3O4). Manganese also combines directly with boron, carbon, sulfur, silicon, or phosphorus but not with hydrogen.

Additional Information

Appearance

A hard, brittle, silvery metal.

Uses

Manganese is too brittle to be of much use as a pure metal. It is mainly used in alloys, such as steel.

Steel contains about 1% manganese, to increase the strength and also improve workability and resistance to wear.

Manganese steel contains about 13% manganese. This is extremely strong and is used for railway tracks, safes, rifle barrels and prison bars.

Drinks cans are made of an alloy of aluminium with 1.5% manganese, to improve resistance to corrosion. With aluminium, antimony and copper it forms highly magnetic alloys.

Manganese(IV) oxide is used as a catalyst, a rubber additive and to decolourise glass that is coloured green by iron impurities. Manganese sulfate is used to make a fungicide. Manganese(II) oxide is a powerful oxidising agent and is used in quantitative analysis. It is also used to make fertilisers and ceramics.
Biological role
Manganese is an essential element in all known living organisms. Many types of enzymes contain manganese. For example, the enzyme responsible for converting water molecules to oxygen during photosynthesis contains four atoms of manganese.

Some soils have low levels of manganese and so it is added to some fertilisers and given as a food supplement to grazing animals.

The average human body contains about 12 milligrams of manganese. We take in about 4 milligrams each day from such foods as nuts, bran, wholegrain cereals, tea and parsley. Without it, bones grow spongier and break more easily. It is also essential for utilisation of vitamin B1.

Natural abundance

Manganese is the fifth most abundant metal in the Earth’s crust. Its minerals are widely distributed, with pyrolusite (manganese dioxide) and rhodochrosite (manganese carbonate) being the most common.

The main mining areas for manganese are in China, Africa, Australia and Gabon. The metal is obtained by reducing the oxide with sodium, magnesium or aluminium, or by the electrolysis of manganese sulfate.

Manganese nodules have been found on the floor of the oceans. These nodules contain about 24% manganese, along with smaller amounts of many other elements.

Manganese-Tile-600x600.png

#67 Re: Jai Ganesh's Puzzles » General Quiz » 2025-07-10 16:42:49

Hi,

#10445. What does the term in Geography Antipodes mean?

#10446. What does the term in Geography Apparent place mean?

#68 Re: Jai Ganesh's Puzzles » English language puzzles » 2025-07-10 16:23:51

Hi,

#5635. What does the noun neutrality mean?

#5636. What does the verb (used with object) neutralize mean?

#69 Re: Jai Ganesh's Puzzles » Doc, Doc! » 2025-07-10 15:57:45

Hi,

#2408. What does the medical term Methylene blue used for?

#73 Re: This is Cool » Miscellany » 2025-07-09 21:19:10

2332) Ocean

Gist

The ocean is a vast body of saltwater that covers approximately 70.8% of Earth's surface. It is a single, interconnected body of water, but for geographical and historical reasons, it's often divided into five main oceans: the Pacific, Atlantic, Indian, Southern (or Antarctic), and Arctic Oceans. The ocean plays a vital role in regulating the planet's climate, supporting a vast array of marine life, and providing resources for human populations.

Summary

The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as oceans (the Pacific, Atlantic, Indian, Antarctic/Southern, and Arctic Ocean), and are themselves mostly divided into seas, gulfs and subsequent bodies of water. The ocean contains 97% of Earth's water and is the primary component of Earth's hydrosphere, acting as a huge reservoir of heat for Earth's energy budget, as well as for its carbon cycle and water cycle, forming the basis for climate and weather patterns worldwide. The ocean is essential to life on Earth, harbouring most of Earth's animals and protist life, originating photosynthesis and therefore Earth's atmospheric oxygen, still supplying half of it.

Ocean scientists split the ocean into vertical and horizontal zones based on physical and biological conditions. Horizontally the ocean covers the oceanic crust, which it shapes. Where the ocean meets dry land it covers relatively shallow continental shelfs, which are part of Earth's continental crust. Human activity is mostly coastal with high negative impacts on marine life. Vertically the pelagic zone is the open ocean's water column from the surface to the ocean floor. The water column is further divided into zones based on depth and the amount of light present. The photic zone starts at the surface and is defined to be "the depth at which light intensity is only 1% of the surface value" (approximately 200 m in the open ocean). This is the zone where photosynthesis can occur. In this process plants and microscopic algae (free-floating phytoplankton) use light, water, carbon dioxide, and nutrients to produce organic matter. As a result, the photic zone is the most biodiverse and the source of the food supply which sustains most of the ocean ecosystem. Light can only penetrate a few hundred more meters; the rest of the deeper ocean is cold and dark (these zones are called mesopelagic and aphotic zones).

Ocean temperatures depend on the amount of solar radiation reaching the ocean surface. In the tropics, surface temperatures can rise to over 30 °C (86 °F). Near the poles where sea ice forms, the temperature in equilibrium is about −2 °C (28 °F). In all parts of the ocean, deep ocean temperatures range between −2 °C (28 °F) and 5 °C (41 °F). Constant circulation of water in the ocean creates ocean currents. Those currents are caused by forces operating on the water, such as temperature and salinity differences, atmospheric circulation (wind), and the Coriolis effect. Tides create tidal currents, while wind and waves cause surface currents. The Gulf Stream, Kuroshio Current, Agulhas Current and Antarctic Circumpolar Current are all major ocean currents. Such currents transport massive amounts of water, gases, pollutants and heat to different parts of the world, and from the surface into the deep ocean. All this has impacts on the global climate system.

Ocean water contains dissolved gases, including oxygen, carbon dioxide and nitrogen. An exchange of these gases occurs at the ocean's surface. The solubility of these gases depends on the temperature and salinity of the water. The carbon dioxide concentration in the atmosphere is rising due to CO2 emissions, mainly from fossil fuel combustion. As the oceans absorb CO2 from the atmosphere, a higher concentration leads to ocean acidification (a drop in pH value).

The ocean provides many benefits to humans such as ecosystem services, access to seafood and other marine resources, and a means of transport. The ocean is known to be the habitat of over 230,000 species, but may hold considerably more – perhaps over two million species. Yet, the ocean faces many environmental threats, such as marine pollution, overfishing, and the effects of climate change. Those effects include ocean warming, ocean acidification and sea level rise. The continental shelf and coastal waters are most affected by human activity.

Details

The ocean is a huge body of saltwater that covers about 71 percent of Earth’s surface. The planet has one global ocean, though oceanographers and the countries of the world have traditionally divided it into five distinct regions: the Pacific, Atlantic, Indian, and Arctic oceans. Beginning in the 20th century, some oceanographers labeled the seas around Antarctica the Southern Ocean, and in 2021 National Geographic officially recognized this fifth ocean.

An estimated 97 percent of the world’s water is found in the ocean. Because of this, the ocean has considerable impact on weather, temperature, and the food supply of humans and other organisms. Despite its size and impact on the lives of every organism on Earth, the ocean remains a mystery. More than 80 percent of the ocean has not been mapped, explored, or even seen by humans. A far greater percentage of the surfaces of the moon and the planet Mars has been mapped and studied than of our own ocean floor.

Although there is much more to learn, oceanographers have already made some amazing discoveries. For example, we know that the ocean contains towering mountain ranges and deep canyons, known as trenches, just like those on land. The peak of the world’s highest mountain—Mount Everest in the Himalaya, measuring 8.85 kilometers (5.49 miles) high—would not even break the surface of the water if it was placed in the Pacific Ocean’s Mariana Trench or Philippine Trench, two of the deepest parts of the ocean.

On the other hand, the Atlantic Ocean is relatively shallow because large parts of its seafloor are made up of continental shelves—parts of the continents that extend far out into the ocean. The average depth of the entire ocean is 3,720 meters (12,200 feet).

It is unknown how many different species call the ocean their home. With many marine ecosystems suffering from rising sea temperatures, pollution, and other problems, some oceanographers believe the number of species is dropping. Still, there may be many positive surprises waiting for oceanographers in the years ahead. It could be that more than 90 percent of the ocean’s species are still undiscovered, with some scientists estimating there are anywhere between a few hundred thousand and a few million more to be discovered. Currently, scientists know of around 226,000 ocean species.

Learning more about the seafloor and the rest of the ocean is the passion of National Geographic Explorer Marcello Calisti. He is a biorobotics expert who is developing an undersea exploration vehicle that uses “legged locomotion,” inspired by the way an octopus moves under water. His long-range goal is to design robots that can explore the depths that are difficult for humans to reach.

Since the ocean is so vast, there is plenty for future oceanographers from all corners of the globe to explore and discover.

Additional Information:

Introduction

An ocean is a huge body of salt water. Oceans cover nearly 71 percent of Earth’s surface. They contain almost 98 percent of all the water on Earth.

There is one world ocean, but it is divided into five main areas: the Pacific, the Atlantic, the Indian, the Arctic, and the Southern, or Antarctic. Together, they can be seen as one world ocean because they have no real borders, and water flows freely between them. Smaller parts of these oceans are called seas, gulfs, and bays.

Ocean Water

Ocean water is salty. The saltiness comes from a chemical substance called sodium chloride, which is dissolved in the water. (The salt that people eat is sodium chloride in the form of crystals.)

Winds and other forces cause ocean water to be constantly in motion. Large amounts of ocean water move around Earth in patterns called currents. Ocean currents may be warm or cold. Warm currents tend to bring warm weather and rain to nearby land. Cold currents tend to cause a dry climate. The Gulf Stream is a warm current that runs north along the eastern coast of the United States.

Winds also cause ocean water to move in waves. Steady, powerful winds cause big waves. Gentle breezes create ripples. Large swells in ocean water usually come from stormy weather.

Tides are another way that ocean water moves. Tides are the rise and fall of ocean levels. That happens throughout the day. On a beach, for example, the ocean covers more sand at high tide than at low tide. The pull of a force called gravity between Earth and the Moon and the Sun causes tides.

Ocean Floor

The ocean floor has many levels. The shallowest part of the oceans, called the continental shelf, lies along the edges of the continents. The edges of the continental shelf slope down toward the deep parts of the oceans, called the basins. At the bottom of the basins are large, flat plains.

In some places, deep cracks called trenches cut into the ocean floor. In other places, underwater mountain chains, called oceanic ridges, rise up from the floor. Earthquakes sometimes occur along the trenches and ridges. Parts of the ridges contain active volcanoes.

Ocean Life

Living things inhabit all levels of Earth’s oceans. Ocean plants grow fairly close to the water’s surface because they need sunlight to stay alive. Sunlight penetrates the water to only about 656 feet (200 meters). The most numerous ocean plants are called phytoplankton. Those tiny, one-celled plants drift with the ocean currents. Various kinds of sea grass and other plants also grow in the world’s oceans. Seaweeds, which are plantlike forms of algae, are plentiful as well.

Like ocean plants, most ocean animals live in shallower water. This is because there are more plants and animals to eat near the water’s surface. But animals also can be found in deep water, including within the oceans’ deepest, darkest trenches.

The largest ocean animal is the blue whale. No larger animal has ever lived on Earth. The tiniest animals are a form of plankton called zooplankton. Hundreds of thousands of other types of animal also live in the ocean. Those include clams, crabs, squid, dolphins, and many different kinds of fish. Corals and sea anemones look like plants, but they are animals, too.

Importance of the Oceans

The world’s oceans are important to life on Earth. Oceans are a great source of food for people around the world. They also provide minerals, oil, and natural gas. Phytoplankton and algae create much of the world’s oxygen. Oceans also help to keep climates stable by storing heat from the Sun.

Today, many dangers threaten the health of the oceans. People pollute oceans by dumping poisonous waste and garbage into them. Ocean pollution reduces oxygen in the water and harms ocean life. Overfishing and oil spills harm ocean life as well.

People called oceanographers study the oceans to try to keep them healthy. Some examine the quality of the water and the way the water moves. Others look at the structures of the seafloors and basins. Another group of oceanographers is interested in the plants and animals that live in oceans.

ocean-waves.jpg

#74 Dark Discussions at Cafe Infinity » Classrooms Quotes » 2025-07-09 20:32:03

Jai Ganesh
Replies: 0

Classrooms Quotes

1. When I was six, the Korean War broke out, and all the classrooms were destroyed by war. We studied under the trees or in whatever buildings were left. - Ban Ki-moon

2. I consider the world, this Earth, to be like a school, and our life the classrooms. - Oprah Winfrey

3. Crowded classrooms and half-day sessions are a tragic waste of our greatest national resource - the minds of our children. - Walt Disney

4. There are two ways to have educational chess in schools, either through after school programs or using chess as a tool in classrooms to improve children's thinking. - Judit Polgar

5. Research shows that there is only half as much variation in student achievement between schools as there is among classrooms in the same school. If you want your child to get the best education possible, it is actually more important to get him assigned to a great teacher than to a great school. - Bill Gates

6. In America the schools have become too permissive, the kids now are controlling the schools, the tail is wagging the dog. We've got to make a change there and get it back to where the teachers have control of the classrooms. - Chuck Norris.

#75 Jokes » Dancer Jokes - VII » 2025-07-09 20:03:22

Jai Ganesh
Replies: 0

Q: Why did the two knives go to the dance together?
A: Because they both looked sharp.
* * *
Q: What do ballerinas run on?
A: Batterie power!
* * *
Q: What is a ducks favorite dance?
A: The quackstep!
* * *
Q: What sort of music do cows like to dance to?
A: Any kind of moosic.
* * *
Q:  Why is it cool to be a dancer?
A: Because no one tells you off for having too much attitude!
* * *

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