Who discovered sickle cell disease?
“Peculiar elongated and sickle-shaped” is how sickle cells were first described in 1904 by intern Ernest Edward Irons when examining the blood of Walter Clement Noel, a 20-year-old first-year dental student from a wealthy Black family in Grenada.
What is the prognosis of sickle cell disease?
Those with sickle cell disease can develop a number of potentially life-threatening complications including anemia, severe pain crises, infections, strokes, and organ damage.
Where did sickle cell disease (SCD) originate?
This is also why sickle cell trait occurs more frequently among those who are descendants of tropical and sub-tropical regions where malaria is or was common. Sickle cell disease is believed to have originated in West Africa, where it has the highest prevalence.
How many people suffer with sickle cell?
Millions of people around the world live with sickle cell disease (SCD). It is most common in Africa, the Middle East, and India. The exact number of people with SCD in the United States is unknown, but the estimate is around 100,000. 1 Experts predict this number will increase over the next few decades.
What was the first sickle made of?
flintAncient Egyptians used sickles made from flint and wood to reap grain. Pieces of flint such as this one were shaped to fit into a wooden haft along with a number of other such inserts, and secured with an adhesive. The flint pieces provided a sharp edge to cut the grain stalks.
Is the sickle still used today?
Harvesting with a sickle is very slow, but because of its simplicity and low cost, it is still widely used over the world, especially to reap cereals such as wheat and rice and also as a gardening tool.
Why do farmers use a sickle?
A sickle is a farming tool with a C-shaped blade mounted on a small handle (about the size of a hammer handle). It's meant to be used with one hand, typically to harvest bundles of plants (like grasses or grains) by cutting them at the base.
Who invented the scythe?
The exact origin of the scythe is unknown, but it was little used in the ancient world. It came into wide use only with agricultural developments of the Carolingian era (8th century ad) in Europe, when the harvesting and storing of hay became important to support livestock through winters.
Does the Grim Reaper carry a scythe or a sickle?
In Greek mythology, Chronos, called Father Time, was the king of titans and the father of Zeus. Cronus was a harvest god and carried a sickle, which is a tool used in harvesting grain. The Grim Reaper carrying a scythe is derived from a combination of Chronus and Cronus.
Can a sickle be used as a weapon?
As a weapon Like other farming tools, the sickle can be used as an improvised bladed weapon. Examples include the Japanese kusarigama and kama, the Chinese chicken sickles, and the makraka of the Zande people of north central Africa.
Can you use a sickle to cut grass?
0:557:06Why we Scythe for Cutting Grass, Mulch and Feed - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd you just got this nice smooth cutting motion like that so it cuts really well. You do need toMoreAnd you just got this nice smooth cutting motion like that so it cuts really well. You do need to sharpen it.
How do you cut a sickle?
0:132:04Hand Scythe - YouTubeYouTubeStart of suggested clipEnd of suggested clipWhat'd you do with this tool is you reach down and you grab a clump of grass put tension on it thenMoreWhat'd you do with this tool is you reach down and you grab a clump of grass put tension on it then you pull this across. Like that and cut the grass. And you just work like this cutting.
How much does a sickle weigh?
It weighs a lot less than the American scythe. An American scythe purchased in a local farm store in Pennsylvania weighs almost 6 pounds (2.70 kilograms), while a European scythe weighs less than 4 pounds (1.75 kilograms).
What is the Grim Reaper's scythe called?
Orcus, the Grim Reaper's Scythe, is a cursed staff wielded by Thanatos, the Greek god of death. It is used to separate the souls of the dead from their bodies.
When did scythes stop being used?
In the 20th century, scythes were replaced almost completely by machines, including the mower and combine. But they still find use in less developed countries, and there are even scythe enthusiasts and competitions throughout Europe and North America.
Is a scythe a knife?
A scythe (/saɪð/ SYDHE) is an agricultural hand tool for mowing grass or harvesting crops. It is historically used to cut down or reap edible grains, before the process of threshing. The scythe has been largely replaced by horse-drawn and then tractor machinery, but is still used in some areas of Europe and Asia.
What is the sickle used for?
The sickle is general purpose harvesting hand tool. It is used for the harvesting of vegetables, cereal crops and cutting of the grass and other vegetative matters. Sickle is one of the most common hand tools used for harvesting of the crops, grass and cutting of other vegetative matters.
What do you mean by sickle?
Definition of sickle (Entry 1 of 3) 1 : an agricultural implement consisting of a curved metal blade with a short handle fitted on a tang. 2 : the cutting mechanism (as of a reaper, combine, or mower) consisting of a bar with a series of cutting elements. sickle.
How do you maintain a sickle tool?
While power tools often break down, the only maintenance a sickle requires is an occasional blade sharpening.Secure the sickle handle tightly in a bench vise with the blade facing away from you. ... Grind away the rounded metal edge -- the dull edge -- on the inside of the blade, using a whetstone or flat file.More items...
Is Sickle Cell contagious?
Sickle cell disease is not contagious. It's hereditary like hair or eye color. You can only get it if both of your parents carry a certain gene trait and pass it on to you.
What is a sickle tool?
Sickle, one of the most ancient of harvesting tools, consisting of a metal blade, usually curved, attached to a short wooden handle. The short handle forces the user to harvest in a stooped or squatting position.
What is a sickle scythe?
Sickle, one of the most ancient of harvesting tools, consisting of a metal blade, usually curved, attached to a short wooden handle. The short handle forces the user to harvest in a stooped or squatting position. The longer-handled scythe, the user of which remains upright, evolved from the sickle. Harvesting with a sickle is very slow, but ...
Why is it so slow to harvest with a sickle?
Harvesting with a sickle is very slow, but because of its simplicity and low cost, it is still widely used over the world, especially to reap cereals such as wheat and rice and also as a gardening tool. Learn More in these related Britannica articles: origins of agriculture: Tools and techniques.
When were sickle inserts invented?
The earliest sickle inserts date to the Neolithic period, with many examples from the Fayum and Merimda Beni Salama (Caton-Thompson and Gardner 1934; Eiwanger 1984, 1988, 1992).
What were sickles made of?
Ancient Egyptians used sickles made from flint and wood to reap grain. Pieces of flint such as this one were shaped to fit into a wooden haft along with a number of other such inserts, and secured with an adhesive. The flint pieces provided a sharp edge to cut the grain stalks.
How long are sickle inserts?
However, there was a fair amount of variability in the lengths of sickle inserts in the fourth millennium BC. Complete examples range from less than 4 cm, to over 12 cm (e.g. Brooklyn Museum 07.447.827; Midant-Reynes and Buchez 2002:348, nos. 185, 187; Rizkana and Seeher 1988: Pl.75 no. 2). Additionally, in Maadi, sickle inserts may have also been made on Canaanean blades imported from the Levant which have different metric and functional attributes (Rizkana and Seeher 1988:35-36). However, such an early date for Canaanean blades is not always accepted (Milevski et al. 2011). The differences in blade sizes during this period suggest that multiple hafting methods could have been practiced, such as both straight and curved sickles. Unfortunately, no wooden sickle hafts dating to the Predynastic Period have been found.
What is used to make sickles?
Furthermore, specialist production of the composite sickles in the New Kingdom is indicated by the use of lime-plaster adhesives. Lime-plaster is much more difficult to produce and use than organic adhesives. Limestone has to be heated to extremely high temperatures (800-1000° Celsius), which requires (substantial) space, fuel, and pyrotechnic expertise. Once the stone has been fired, the resulting lime must be handled carefully because it can burn a person’s skin. After water is added and the putty mixture is applied and shaped, it has to rest and harden over a number of days. This involved process does not seem to be one that any farmer could carry out at will to make or repair a sickle, but rather the domain of specialists. Other suggested sickle adhesives involve organic materials such as gums, resins, and beeswax, or mixtures of these with inorganic materials (Caton-Thompson and Gardner 1934:45; Graves-Brown 2010:420; Lucas 1948:8; Spurrell 1892, 1894). However, Endlicher and Tillman (1997) analyzed adhesives on sickle inserts from New Kingdom Tell el-Dab’a using thin section petrography, X-ray diffraction, X-ray fluorescence, and scanning electron microscopy. They argued that the samples were lime plaster based on evidence for calcite and high heating. A number of the sickle inserts from Lisht from The Met’s collection retain adhesives that are similar to the Tell el-Dab’a examples, consisting of a hard light-gray material with sand temper, that often covers more of one face than the other (MMA 09.180.1377-.1379 and 48.105.41m,o,p,r). X-ray diffraction analysis of MMA 09.180.1378 indicated that the matrix is primarily calcite, so it is certainly a lime-based adhesive. This evidence, along with the similarities to the Tel el-Dab’a examples, suggest that the Lisht adhesives are also lime-plaster. The use of lime-plaster adhesives for sickles was likely widespread in the New Kingdom because adhesives similar to the Tell el-Dab’a and Lisht examples are present at other New Kingdom sites (Amarna: Graves-Brown n.d.; Kemp and Stevens 2010:Pl. 22.8; Deir el Medina: Bruyère 1939:Pl. 42).
How did farmers obtain sickle inserts in the Predynastic Period?
Thus, how a farmer obtained sickle inserts in the Predynastic Period may have depended on a variety of factors, such as their personal skills, social connections, where they lived, or local traditions. Starting in the Early Dynastic Period, the standardization of sickle inserts increased.
What is variability in sickle inserts?
This variation may reflect different emerging or competing systems of production, and it is possible that the production of some inserts was more specialized than others. Thus, how a farmer obtained sickle inserts in the Predynastic Period may have depended on a variety of factors, such as their personal skills, social connections, where they lived, or local traditions.
What material was used to make sickles in Egypt?
With use, the flint would wear down and develop a shiny gloss. The flint inserts could be re-sharpened or replaced as needed. Flint , rather than copper alloy, was the primary material used to make sickles in Egypt until the first millennium B.C. when iron became more widely available.
What was the first paper-like material?
Papyrus sheets are the earliest paper-like material – all other civilisations used stone, clay tablets, animal hide, wood materials or wax as a writing surface. Papyrus was, for over 3000 years, the most important writing material in the ancient world. It was exported all around the Mediterranean and was widely used in the Roman Empire as well as the Byzantine Empire. Its use continued in Europe until the seventh century AD, when an embargo on exporting it forced the Europeans to use parchment.
What diseases did the Egyptians suffer?
The Egyptians were so expert at preserving the bodies of the dead that after thousands of years we know of the diseases they suffered such as arthritis, tuberculosis of the bone, gout, tooth decay, bladder stones, and gallstones; there is evidence, too, of the disease bilharziasis (schistosomiasis), caused by small, parasitic flatworms, which still exists in Egypt today. There seems to have been no syphilis or rickets.
What did the Egyptians and Mesopotamians discover?
The Egyptians as well as the Mesopotamians independently discovered that by mixing a small quantity of tin ore with copper ores they could make bronze which is harder and more durable. This set off a chain of connected innovations that could not have happened without the primary discovery.
How did the Egyptians create the solar calendar?
The Egyptians devised the solar calendar by recording the yearly reappearance of Sirius (the Dog Star) in the eastern sky. It was a fixed point which coincided with the yearly flooding of the Nile. Their calendar had 365 days and 12 months with 30 days in each month and an additional five festival days at the end of the year. However, they did not account for the additional fraction of a day and their calendar gradually became incorrect. Eventually Ptolemy III added one day to the 365 days every four years.
What did the Greeks learn from the Egyptians?
For example the Greeks sometimes take the credit for inventing mathematics but they learned their math from the Egyptians then later developed and improved upon what the Egyptian achieved. 3000 BC appears to have been a critical time for the development of technology, especially metal making.
Why did the Egyptians build canals and irrigation ditches?
The Egyptians constructed canals and irrigation ditches to harness Nile river’s yearly flood and bring water to distant fields.
What is the ingredient in ancient Egyptian toothpaste?
Its ingredients included powdered of ox hooves, ashes, burnt eggshells and pumice. Another toothpaste recipe and a how-to-brush guide was written on a papyrus from the fourth century AD describes how to mix precise amounts of rock salt, mint, dried iris flower and grains of pepper, to form a “powder for white and perfect teeth.”