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The South African province of KwaZulu-Natal, more commonly referred to as the Zulu Kingdom, is named after the Zulu people who have inhabited the area since the late 1400s. KwaZulu translates to mean "Place of Heaven." "Natal" was the name the Portuguese explorers gave this region when they arrived in 1497. At that time, only a few Zulu clans occupied the area. By the late 1700s, the AmaZulu clan, meaning "People of Heaven," constituted a significant nation. Today the Zulu clan represents the largest ethnic group in South Africa, with at least 11 million people in the kingdom. The Zulu people are known around the world for their elaborate glass beadwork, which they wear not only in their traditional costumes but as part of their everyday apparel. It is possible to learn much about the culture of the Zulu clan through their beadwork.
The glass bead trade in the province of KwaZulu-Natal is believed to be a fairly recent industry. In 1824, an Englishman named Henry Francis Fynn brought glass beads to the region to sell to the African people. Though the British are not considered the first to introduce glass beads, they were a main source through which the Zulu people could access the merchandise they needed. Glass beads had already been manufactured by the Egyptians centuries earlier around the same time when glass was discovered. Some research points to the idea that Egyptians tried to fool South Africans with glass by passing it off as jewels similar in value to gold or ivory. Phoenician mariners brought cargoes of these beads to Africa along with other wares. Before the Europeans arrived, many Arab traders brought glass beads down to the southern countries via camelback. During colonization', the Europeans facilitated and monopolized the glass bead market, and the Zulu nation became even more closely tied to this art form.
The Zulu people were not fooled into believing that glass beads were precious stones but, rather, used the beads to establish certain codes and rituals in their society. In the African tradition, kings were known to wear beaded regalia so heavy that they required the help of attendants to get out of their thrones. Zulu beadwork is involved in every realm of society, from religion and politics to family and marriage. Among the Zulu women, the craft of beadwork is used as an educational tool as well as a source of recreation and fashion. Personal adornment items include jewelry, skirts, neckbands, and aprons. Besides clothing and accessories, there are many other beaded objects in the Zulu culture, such as bead-covered gourds, which are carried around by women who are having fertility problems. Most importantly, however, Zulu beadwork is a source of communication. In the Zulu tradition, beads are a part of the language with certain words and symbols that can be easily read. A finished product is considered by many artists and collectors to be extremely poetic.
The code behind Zulu beadwork is relatively basic and extremely resistant to change. A simple triangle is the geometric shape used in almost all beaded items. A triangle with the apex pointing downward signifies an unmarried man, while one with the tip pointing upward is worn by an unmarried woman. Married women wear items with two triangles that form a diamond shape, and married men signify their marital status with two triangles that form an hourglass shape. Colors are also significant, though slightly more complicated since each color can have a negative and a positive meaning. Educated by their older sisters, young Zulu girls quickly learn how to send the appropriate messages to a courting male. Similarly, males learn how to interpret the messages and how to wear certain beads that express their interest in marriage.
The codes of the beads are so strong that cultural analysts fear that the beadwork tradition could prevent the Zulu people from progressing technologically and economically. Socioeconomic data shows that the more a culture resists change the more risk there is in a value system falling apart. Though traditional beadwork still holds a serious place in Zulu culture, the decorative art form is often modified for tourists, with popular items such as the beaded fertility doll.
Though penguins are assumed to be native to the South Pole, only four of the seventeen species have evolved the survival adaptations necessary to live and breed in the Antarctic year round. The physical features of the Adelie, Chinstrap, Gentoo, and Emperor penguins equip them to withstand the harshest living conditions in the world. Besides these four species, there are a number of others, including the yellow feathered Macaroni penguin and the King penguin that visit the Antarctic regularly but migrate to warmer waters to breed. Penguins that live in Antarctica year round have a thermoregulation system and a survival sense that allows them to live comfortably both on the ice and in the water.
In the dark days of winter, when the Antarctic sees virtually no sunlight, the penguins that remain on the ice sheet sleep most of the day. To retain heat, penguins huddle in communities of up to 6,000 of their own species. When it's time to create a nest, most penguins build up a pile of rocks on top of the ice to place their eggs. The Emperor penguin, however, doesn't bother with a nest at all. The female Emperor lays just one egg and gives it to the male to protect while she goes off for weeks to feed. The male balances the egg on top of his feet, covering it with a small fold of skin called a brood patch. In the huddle, the male penguins rotate regularly so that none of the penguins have to stay on the outside of the circle exposed to the wind and cold for long periods of time. When it's time to take a turn on the outer edge of the pack, the penguins tuck their feathers in and shiver. The movement provides enough warmth until they can head back into the inner core and rest in the warmth. In order to reduce the cold of the ice, penguins often put their weight on their heels and tails. Antarctic penguins also have complex nasal passages that prevent 80 percent of their heat from leaving the body. When the sun is out, the black dorsal plumage attracts its rays and penguins can stay warm enough to waddle or slide about alone.
Antarctic penguins spend about 75 percent of their lives in the water. A number of survival adaptations allow them to swim through water as cold as -2 degrees Celsius. In order to stay warm in these temperatures, penguins have to keep moving. Though penguins don't fly in the air, they are often said to fly through water. Instead of stopping each time they come up for air, they use a technique called "porpoising," in which they leap up for a quick breath while swiftly moving forward: Unlike most birds that have hollow bones for flight, penguins have evolved hard solid bones that keep them low in the water. Antarctic penguins also have unique feathers that work similarly to a waterproof diving suit. Tufts of down trap a layer of air within the feathers, preventing the water from penetrating the penguin's skin. The presÂÂ¬sure of a deep dive releases this air, and a penguin has to rearrange the feathers through a process called "preening." Penguins also have an amazing circulatory system, which in extremely cold waters diverts blood from the flippers and legs to the heart.
While the harsh climate of the Antarctic doesn't threaten the survival of Antarctic penguins, overheating can be a concern, and therefore, global warming is a threat to them. Temperate species have certain physical features such as fewer feathers and less blubber to keep them cool on a hot day. African penguins have bald patches on their legs and face where excess heat can be released. The blood vessels in the penguin's skin dilate when the body begins to overheat, and the heat rises to the surface of the body. Penguins who are built for cold winters of the Antarctic have other survival techniques for a warm day, such as moving to shaded areas, or holding their fins out away from their bodies.
A Myths related to the causes and symptoms of "colorblindness" abound throughout the world. The term itself is misleading, since it is extremely rare for anyone to have a complete lack of color perception. By look ing into the myths related to color blindness, one can learn many facts about the structure and genetics o the human eye. It is a myth that colorblind people see the world as if it were a black and white movie. There are very few cases of complete colorblindness. Those who have a complete lack of color perception are referred to as monochromatics, and usually have a serious problem with their overall vision as well as an inability to see colors. The fact is that in most cases of colorblindness, there are only certain shades that a person cannot distinguish between. These people are said to be dichromatic. They may not be able to tell the difference between red and green, or orange and yellow. A person with normal color vision has what is called trichromatic vision. The difference between the three levels of color perception have to do with the cones in the human eye. A normal human eye has three cones located inside the retina: the red cone, the green cone, and the yellow cone. Each cone contains a specific pigment whose function is to absorb the light of these colors and the combinations of them. People with trichromatic vision have all three cones in working order. When one of the three cones does not function properly, dichromatic vision occurs.
B Some people believe that only men can be colorblind. This is also a myth, though it is not completely untrue. In an average population, 8% of males exhibit some form of colorblindness, while only 0.5% of women do. While there may be some truth to the idea that more men have trouble matching their clothing than women, the reason that color vision deficiency is predominant in males has nothing to do with fashion. The fact is that the gene for color blindness is located on the X chromosome, which men only have one of. Females have two X chromosomes, and if one carries the defective gene, the other one naturally compensates. Therefore, the only way for a female to inherit colorblindness is for both of her X chromosomes to carry the defective gene. This is why the incidence of color deficiency is sometimes more prevalent in extremely small societies that have a limited gene pool.
C It is true that all babies are born colorblind. A baby's cones do not begin to differentiate between many different colors until he is approximately four months old. This is why many of the modern toys for very young babies consist of black and white patterns or primary colors, rather than traditional soft pastels. However, some current research points to the importance of developing an infant's color visual system. In 2004, Japanese researcher Yoichi Sugita of the Neuroscience Research Institute performed an experiment that would suggest that color vision deficiency isn't entirely genetic. In his experiment, he subjected a group of baby monkeys to monochromatic lighting for one year. He later compared their vision to normal monkey who had experienced the colorful world outdoors. It was found that the test monkeys were unable to perform the color-matching tasks that the normal monkeys could. Nevertheless, most cases of colorblindness are attributed to genetic factors that are present at birth.
D Part of the reason there are so many inconsistencies related to colorblindness, or "color vision deficiency" as it is called in the medical world, is that it is difficult to know exactly which colors each human can see. Children are taught from a very young age that an apple is red. Naming colors allows children to associate a certain shade with a certain name, regardless of a color vision deficiency. Someone who never takes a color test can go through life thinking that what they see as red is called green. Children are generally tested for colorblindness at about four years of age. The Ishihara Test is the most common, though it is highly criticized' because it requires that children have the ability to recognize numerals. In the Ishihara Test, a number made up of colored dots is hidden inside a series of dots of a different shade. Those with normal vision can distinguish the number from the background, while those with color vision deficiency will only see the dots.
E While many of the myths related to colorblindness have been busted by modern science, there are still a few remaining beliefs that require more research in order to be labeled as folklore. For example, there is a long-standing belief that colorblindness can aid military soldiers because it gives them the ability to see through camouflage. Another belief is that everyone becomes colorblind in an emergency situation. The basis of this idea is that a catastrophic event can overwhelm the brain, causing it to utilize only those receptors needed to perform vital tasks. In general, identifying color is not considered an essential task in a life or death situation.
Tornadoes, violently rotating columns of air, occur when a change in wind direction, coupled with an increase in wind speed, results in a spinning effect in the lower atmosphere. These whirling movements, which may not be visible to the naked eye, are exacerbated when the rotating air column shifts from a horizontal to a vertical position. As the revolving cloud draws in the warm air that surrounds it at ground level, its spinning motion begins to accelerate, thereby creating a funnel that extends from the cloud above it to the ground below. In this way, tornadoes become pendent from low pressure storm clouds.
When a tornado comes into contact with the ground, it produces a strong upward draft known as a vortex, a spiraling column of wind that can reach speeds in excess of 200 miles per hour. Traveling across the landscape, the tornado wreaks a path of concentrated destruction. It is not uncommon for these twisters to lift heavy objects, like cars or large animals, and throw them several miles. Houses that succumb to the force of the tornado seem to explode as the low air pressure inside the vortex collides with the normal air pressure inside the buildings.
Tornadoes can occur at any time of the year, but are typically most frequent during the summer months. Equally, tornadoes can happen at any time during the day, but usually occur between 3:00 in the afternoon and 9:00 in the evening. While these fierce funnels occur in many parts of the world, they are most common in the United States. On average, there are 1,200 tornadoes per year in this vast nation, causing 70 fatalities and 1,500 injuries.
Although taking myriad shapes and sizes, tornadoes are generally categorized as weak, strong, or violent. The majority of all tornadoes are classified as weak, meaning that their duration is less than 10 minutes and they have a speed under 110 miles per hour. Comprising approximately 10 percent of all twisters, strong tornadoes may last for more than 20 minutes and reach speeds up to 205 miles per hour. Violent tornadoes are the rarest, occurring less than one percent of the time. While uncommon, tornadoes in this classification are the most devastating, lasting more than one hour and resulting in the greatest loss of life. Even though only violent tornadoes can completely destroy a well-built, solidly-constructed home, weaker ones can also cause great damage.
Owing to the powerful and destructive nature of these winds, there are, perhaps not surprisingly, a number of myths and misconceptions surrounding them. For instance, many people mistakenly believe that tornadoes never occur over rivers, lakes, and oceans; yet, waterspouts, tornadoes that form over bodies of water, often move onshore and cause extensive damage to coastal areas. In addition, tornadoes can accompany hurricanes and tropical storms as they move to land. Another common myth about tornadoes is that damage to built structures, like houses and office buildings, can be avoided if windows are opened prior to the impact of the storm. Based on the misunderstanding that open windows might equalize the pressure inside the structure and minimize the damage to it, this action can instead result in fatal injury.
Because of the profound effects that tornadoes have on communities and their inhabitants, safety measures are of paramount importance during adverse weather conditions. Drivers often attempt to outrun tornadoes in their cars, but it is extremely unsafe to do so. Automobiles offer very little protection when twisters strike, so drivers should abandon their vehicles and seek safe shelter. Mobile homes afford little shelter, so residents of these homes should go to an underground floor of the sturdiest nearby building. In the case of a building having no underground area, a person should go to the lowest floor of the building and place him or herself under a piece of heavy furniture. If no building is available, a person caught in a tornado should lie prostate in a nearby ditch or other depressed area of land and cover his or her head.