Mois : février 2017

A hairstyle, hairdo, or haircut refers to the styling of hair, usually on the human scalp. Sometimes, this could also mean an editing of beard hair. The fashioning of hair can be considered an aspect of personal grooming, fashion, and cosmetics, although practical, cultural, and popular considerations also influence some hairstyles. The oldest known depiction of hair braiding dates back about 30,000 years. In ancient civilizations, women’s hair was often elaborately and carefully dressed in special ways. In Imperial Rome, women wore their hair in complicated styles. From the time of the Roman Empire until the Middle Ages, most women grew their hair as long as it would naturally grow. During the Roman Empire as well as in the 16th century in the western world, women began to wear their hair in extremely ornate styles. In the later half of the 15th century and on into the 16th century a very high hairline on the forehead was considered attractive. During the 15th and 16th centuries, European men wore their hair cropped no longer than shoulder-length. In the early 17th century male hairstyles grew longer, with waves or curls being considered desirable.

The male wig was pioneered by King Louis XIII of France (1601–1643) in 1624. Perukes or periwigs for men were introduced into the English-speaking world with other French styles in 1660. Late 17th-century wigs were very long and wavy, but became shorter in the mid-18th century, by which time they were normally white. Short hair for fashionable men was a product of the Neoclassical movement. In the early 19th century the male beard, and also moustaches and sideburns, made a strong reappearance. From the 16th to the 19th century, European women’s hair became more visible while their hair coverings grew smaller. In the middle of the 18th century the pouf style developed. During the First World War, women around the world started to shift to shorter hairstyles that were easier to manage. In the early 1950s women’s hair was generally curled and worn in a variety of styles and lengths. In the 1960s, many women began to wear their hair in short modern cuts such as the pixie cut, while in the 1970s, hair tended to be longer and looser. In both the 1960s and 1970s many men and women wore their hair very long and straight.In the 1980s, women pulled back their hair with scrunchies. During the 1980s, punk hairstyles were adopted by some people.

Throughout times, people have worn their hair in a wide variety of styles, largely determined by the fashions of the culture they live in. Hairstyles are markers and signifiers of social class, age, marital status, racial identification, political beliefs, and attitudes about gender.

In many cultures, often for religious reasons, women’s hair is covered while in public, and in some, such as Haredi Judaism or European Orthodox communities, women’s hair is shaved or cut very short, and covered with wigs.Only since the end of World War I have women begun to wear their hair short and in fairly natural styles.

High-heeled footwear (often abbreviated as high heels or simply heels) is footwear that raises the heel of the wearer’s foot significantly higher than the toes. When both the heel and the toes are raised equal amounts, as in a platform shoe, it is technically not considered to be a high heel; however, there are also high-heeled platform shoes. High heels tend to give the aesthetic illusion of longer, more slender legs. High heels come in a wide variety of styles, and the heels are found in many different shapes, including stiletto, pump (court shoe), block, tapered, blade, and wedge.

According to high-fashion shoe websites like Jimmy Choo and Gucci, a « low heel » is considered less than 2.5 inches (6.4 centimeters), while heels between 2.5 and 3.5 inches (6.4 and 8.9 cm) are considered « mid heels », and anything over that is considered a « high heel ». The apparel industry would appear to take a simpler view: the term « high heels » covers heels ranging from 2 to 5 inches (5.1 to 12.7 cm) or more. Extremely high-heeled shoes, such as those exceeding 6 inches (15 cm), strictly speaking, are no longer considered apparel but rather something akin to « jewelry for the feet ». They are worn for display or the enjoyment of the wearer.

High heels are not a modern invention but there is confusion regarding when it was developed. Research shows that high heels can be traced back to ancient Egypt. In the middle of the second millennium BC, Egyptians began to frequently uses sandals. Retention was obtained generally by the Egyptians by a T or V thong passing through the sole. Egyptian butchers also wore heeled shoes for practical purposes, that is, in order to keep their feet clean of any blood while slaughtering animals.

Things started to change when during the European renaissance, the high heel became a status symbol worn by both male and females from the higher social statuses. Catherine de Medici a Franco/Italian noblewomen pioneered the use of heels as a fashion statement. Catherine de Medici is believed to have worn them to impress the French court when she wed the Duke of Orleans, the future king. It is believed to be the first instance when heels were worn however, this reference may be apocryphal, as the development of heels did not begin to come about until the late 1580s, based on iconographic evidence and extant pieces. Two hundred years later King Louis XIV of France decreed that only nobility could wear heels. Seventeenth-century portraits of King Louis XIV depict the various intricate heels worn by the king and they were often decorated with miniature battle scenes.

During the 16th century, European royalty, such as Catherine de Medici and Mary I of England, started wearing high-heeled shoes to make them look taller or larger than life. By 1580, men wore them, and a person with authority or wealth was often referred to as « well-heeled ». Since the French Revolution (1789-1799) the trend wearing high heels was ended to avoid any associating with the old aristocracy and its opulence. Since people wished to avoid the appearance of wealth, heels were largely eliminated from the common market for both men and women and replace by casual fashion and shoe wear. From the beginning of the Baroque the heel came back to shoes.

It is sometimes suggested that raised heels were a response to the problem of the rider’s foot slipping forward in stirrups while riding. The « rider’s heel », approximately 1 1⁄2 inches (3.8 cm) high, appeared in Europe around 1600. The leading edge was canted forward to help grip the stirrup, and the trailing edge was canted forward to prevent the elongated heel from catching on underbrush or rock while backing up, such as in on-foot combat. These features are evident today in riding boots, notably cowboy boots.

Diamond is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at standard conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells.

Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors).

Most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 118 mi) in the Earth’s mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth’s surface through deep volcanic eruptions by magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a HPHT method which approximately simulates the conditions in the Earth’s mantle. An alternative, and completely different growth technique is chemical vapor deposition (CVD). Several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have been developed to distinguish natural diamonds, synthetic diamonds, and diamond simulants. The word is from the ancient Greek ἀδάμας – adámas « unbreakable ».

The name diamond is derived from the ancient Greek αδάμας (adámas), « proper », « unalterable », « unbreakable », « untamed », from ἀ- (a-), « un- » + δαμάω (damáō), « I overpower », « I tame ».Diamonds are thought to have been first recognized and mined in India, where significant alluvial deposits of the stone could be found many centuries ago along the rivers Penner, Krishna and Godavari. Diamonds have been known in India for at least 3,000 years but most likely 6,000 years.

Diamonds have been treasured as gemstones since their use as religious icons in ancient India. Their usage in engraving tools also dates to early human history.The popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns.

In 1772, Antoine Lavoisier used a lens to concentrate the rays of the sun on a diamond in an atmosphere of oxygen, and showed that the only product of the combustion was carbon dioxide, proving that diamond is composed of carbon. Later in 1797, Smithson Tennant repeated and expanded that experiment. By demonstrating that burning diamond and graphite releases the same amount of gas, he established the chemical equivalence of these substances.

The most familiar uses of diamonds today are as gemstones used for adornment, a use which dates back into antiquity, and as industrial abrasives for cutting hard materials. The dispersion of white light into spectral colors is the primary gemological characteristic of gem diamonds. In the 20th century, experts in gemology developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat (its weight), cut (quality of the cut is graded according to proportions, symmetry and polish), color (how close to white or colorless; for fancy diamonds how intense is its hue), and clarity (how free is it from inclusions).A large, flawless diamond is known as a paragon.