Ochre - The Oldest Known Natural Pigment in the World

Ochre (rarely spelled ocher and often referred to as yellow ochre) is one of a variety of forms of iron oxide which are described as earth-based pigments. These pigments, used by ancient and modern artists, are made of iron oxyhydroxide, which is to say they are natural minerals and compounds composed of varying proportions of iron (Fe3 or Fe2), oxygen (O) and hydrogen (H). Other natural forms of earth pigments related to ochre include sienna, which is similar to yellow ochre but warmer in color and more translucent; and umber, which has goethite as its primary component and incorporates various levels of manganese. Red oxides or red ochres are hematite-rich forms of yellow ochres, commonly formed from aerobic natural weathering of iron-bearing minerals. Prehistoric and Historic Uses Natural iron-rich oxides provided red-yellow-brown paints and dyes for a wide range of prehistoric uses, including but in no way limited to rock art paintings, pottery, wall paintings and cave art, and human tattoos. Ochre is the earliest known pigment used by humans to paint our world--perhaps as long ago as 300,000 years. Other documented or implied uses are as medicines, as a preservative agent for animal hide preparation, and as a ​loading agent for adhesives (called  mastics). Ochre is often associated with human burials: for example, the Upper Paleolithic cave site of Arene Candide has an early use of ochre at a burial of a young man 23,500 years ago. The site of Paviland Cave in the UK, dated to about the same time, had a burial so soaked in red ochre he was (somewhat mistakenly) called the Red Lady. Natural Earth Pigments Before the 18th and 19th century, most pigments used by artists were of natural origin, made up of mixtures of organic dyes, resins, waxes, and minerals. Natural earth pigments like ochres consist of three parts: the principle color-producing component (hydrous or anhydrous iron oxide), the secondary or modifying color component (manganese oxides within umbers or carbonaceous material within brown or black pigments) and the base or carrier of the color (almost always clay, the weathered product of silicate rocks). Ochre is thought generally to be red, but in fact is a naturally-occurring yellow mineral pigment, consisting of clay, siliceous materials and the hydrated form of iron oxide known as limonite. Limonite is a general term referring to all forms of hydrated iron oxide, including goethite, which is the fundamental component of the ochre earths. Getting Red from Yellow Ochre contains a minimum of 12% iron oxyhydroxide, but the amount can range up to 30% or more, giving rise to the wide range of colors from light yellow to red and brown. The intensity of color depends on the degree of oxidation and hydration of the iron oxides, and the color becomes browner depending on the percentage of manganese dioxide, and redder based on the percentage of hematite. Since ochre is sensitive to oxidation and hydration, the yellow can be turned red by heating goethite (FeOOH) bearing pigments in yellow earth and converting some of it to hematite. Exposing yellow goethite to temperatures above 300 degrees Celcius will gradually dehydrate the mineral, converting it first to orange-yellow and then red as hematite is produced. Evidence of heat-treatment of ochre dates at least as early as the Middle Stone Age deposits in Blombos cave, South Africa. How Old Is Ochre Use? Ochre is very common on archaeological sites worldwide. Certainly, Upper Paleolithic cave art in Europe and Australia contain the generous use of the mineral: but ochre use is much older. The earliest possible use of ochre discovered so far is from a Homo erectus site about 285,000 years old. At the site called GnJh-03 in the Kapthurin formation of Kenya, a total of five kilograms (11 pounds) of ochre in more than 70 pieces was discovered. By 250,000-200,000 years ago, Neanderthals were using ochre, at the Maastricht Belvà ©dà ¨re site in The Netherlands (Roebroeks) and the Benzu rock shelter in Spain. Ochre and Human Evolution Ochre was part of the first art of the Middle Stone Age (MSA) phase in Africa called Howiesons Poort. The early modern human assemblages of 100,000-year-old MSA sites including Blombos Cave and Klein Kliphuis in South Africa have been found to include examples of engraved ochre, slabs of ochre with carved patterns deliberately cut into the surface. Spanish paleontologist Carlos Duarte (2014) has even suggested that using red ochre as a pigment in tattoos (and otherwise ingested) may have had a role in human evolution, as it would have been a source of iron directly to the human brain, perhaps making us smarter. The presence of ochre mixed with milk proteins on an artifact from a 49,000-year-old MSA level at Sibudu cave in South Africa is suggested to have been used to make the ochre liquid, probably by killing a lactating bovid (Villa 2015). Identifying the Sources The yellow-red-brown ochre pigments used in paintings and dyes are often a mixture of mineral elements, both in their natural state and as a result of deliberate mixing by the artist. Much of recent research on ochre and its natural earth relatives has been focused on identifying the specific elements of a pigment used in a particular paint or dye. Determining what a pigment is made up of allows the archaeologist to find out the source where the paint was mined or collected, which could provide information about long-distance trade. Mineral analysis helps in conservation and restoration practices; and in modern art studies, assists in the technical examination for authentication, identification of a specific artist, or the objective description of an artists techniques. Such analyses have been difficult in the past because older techniques required the destruction of some of the paint fragments. More recently, studies that use microscopic amounts of paint or even completely non-invasive studies such as various types of spectrometry, digital microscopy, x-ray fluorescence, spectral reflectance, and x-ray diffraction have been used successfully to split out the minerals used, and determine the type and treatment of the pigment. Sources Bu K, Cizdziel JV, and Russ J. 2013. The Source of Iron-Oxide Pigments Used in Pecos River Style Rock Paints. Archaeometry 55(6):1088-1100.Buti D, Domenici D, Miliani C, Garcà ­a Sà ¡iz C, Gà ³mez Espinoza T, Jà ­menez Villalba F, Verde Casanova A, Sabà ­a de la Mata A, Romani A, Presciutti F et al. 2014. Non-invasive investigation of a pre-Hispanic Maya screenfold book: the Madrid Codex. Journal of Archaeological Science 42(0):166-178.Cloutis E, MacKay A, Norman L, and Goltz D. 2016. Identification of historic artists pigments using spectral reflectance and X-ray diffraction properties I. Iron oxide and oxy-hydroxide-rich pigments. Journal of Near Infrared Spectroscopy 24(1):27-45.Dayet L, Le Bourdonnec FX, Daniel F, Porraz G, and Texier PJ. 2015. Ochre Provenance and Procurement Strategies During The Middle Stone Age at Diepkloof Rock Shelter, South Africa. Archaeometry:n/a-n/a.Dayet L, Texier PJ, Daniel F, and Porraz G. 2013. Ochre resources from the Middle Stone Age sequence of Diepkloof Rock Shelter, Western Cape, South Africa. Journal of Archaeological Science 40(9):3492-3505.Duarte CM. 2014. Red ochre and shells: clues to human evolution. Trends in Ecology Evolution 29(10):560-565.Eiselt BS, Popelka-Filcoff RS, Darling JA, and Glascock MD. 2011. Hematite sources and archaeological ochres from Hohokam and O’odham sites in central Arizona: an experiment in type identification and characterization. Journal of Archaeological Science 38(11):3019-3028.Erdogu B, and Ulubey A. 2011. Colour symbolism in the prehistoric architecture of central Anatolia and Raman Spectroscopic Investigation of red ochre in Chalcolithic Çatalhà ¶yà ¼k. Oxford Journal Of Archaeology 30(1):1-11.Henshilwood C, DErrico F, Van Niekerk K, Coquinot Y, Jacobs Z, Lauritzen S-E, Menu M, and Garcia-Moreno R. 2011. A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa. Science 334:219-222.Moyo S, Mphuthi D, Cukrowska E, Henshilwood CS, van Niekerk K, and Chimuka L. 2016. Blombos Cave: Middle Stone Age ochre differentiation through FTIR, ICP OES, ED XRF and XRD. Quaternary International 404, Part B:20-29.Rifkin RF. 2012. Processing ochre in the Middle Stone Age: Testing the inference of prehistoric behaviours from actualistically derived experimental data. Journal of Anthropological Archaeology 31(2):174-195.Roebroeks W, Sier MJ, Kellberg Nielsen T, De Loecker D, Pares JM, Arps CES, and Mucher HJ. 2012. Use of red ochre by early Neandertals. Proceedings of the National Academy of Sciences 109(6):1889-1894.Villa P, Pollarolo L, Degano I, Birolo L, Pasero M, Biagioni C, Douka K, Vinciguerra R, Lucejko JJ, and Wadley L. 2015. A Milk and Ochre Paint Mixture Used 49,000 Years Ago at Sibudu, South Africa. PLoS ONE 10(6):e0131273.

Essay about Italian and Northern European Renaissance

Italian and Northern European Renaissance The Italian and Northern Europe Renaissances were both an important mark in history by changing the ideals of life, thought, culture, and art of the people’s of this time. In this paper I will explain the motive for change in these cultures, including the similarities and differences of the two cultures. The Italian and Northern European Renaissance was the marking point for leaving behind the old ways and moving into the more classical ideals and civilizations for Italy and Northern Europe. However, Northern Europe developed their ideals more slowly then Italy did. â€Å"For one thing, the north held on to Gothic (or Middle Ages) art and architecture with a tighter, longer grip†¦show more content†¦The classical aspects were used to humanize the Christian and secular buildings. The High Renaissance in Italy, although short lived, was extremely important on the influences of future Italian art. During the High Renaissance the main focus on Florence, for the arts, shifted to Rome due to the power and wealth from the popes. Because of the move from Florence to Rome, the two most important factors of this time, Classicism and Christianity, were merged into one. â€Å"Italian ideas were also brought northward through trade and commerce into Europe, where they had a tremendous amount of influence on the artistic traditions there as well† (Benton amp; DiYanni, 2008). Both the Italian and Northern European Renaissance had interest in changing their ideals in individualism, humanism, and classicism, which has a large impact on their cultures, and arts. Many of the literary works of this time expressed the same interests between Italy and Northern Europe. Examples can be seen in the writings of Petrarch (Italian) and Michel de Montaigne (Northern European). Both of these writers expressed the importance and idealism of humanism. 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Subdural Hematoma - Venous Thromboembolism and Seizures

Question: Write about theSubdural Hematoma, Venous Thromboembolism and Seizures. Answer: Subdural Hematoma This is a condition that develops when blood accumulates between the layers of the tissues that surround the brain. It is usually associated with bleeding between the dura and the other layers within the brain. High accumulation of blood in the brain results in an increased pressure. The condition is always caused by a number of factors including injury in the head e.g from a serious collision. Individual with bleeding conditions are usually at high risk to suffer the condition. Subdural hematoma is associated with a number of symptoms including loss of consciousness and one may become comatose within a second when exposed to serious and sudden head injuries. Development of subdural hematoma may take days even after the head injury however, the signs may be shown later. Other symptoms of the conditions include; behavioral change, headache, confusion, nausea and vomiting and increased drowsiness among other symptoms (Leroy et al., 2015). A number of interventions have been put in place to manage the condition. Persons who undergo medical treatment after the head injuries are always exposed to head imaging by the use of computer tomography. This method creates images within the skull and is able to detect any traces of subdural hematoma present. Angiography may also be used to handle the condition since the x-ray screen shows the blood flow within the brain. A hole can also be drilled on the skull and blood is removed from within the brain by suction process. Alternatively, part of the skull can be removed for ease access of the subdural hematoma in order to reduce pressure. Venous Thromboembolism This is a condition when blood clot forms in the deep veins within the leg and usually requires immediate medical attention when possible since it is a serious condition when not closely monitored. The blood clot usually blocks the flow of blood and causes greater pain and at times swelling of the skin and the veins in the lower limb or thigh. The temperatures of the body around these parts are usually high especially when exposed to the feeling of touch or at times reddish discoloration may be seen. The condition is usually characterized chest pains always below the rib cage and the pain usually increases when the breathing depth is increased. The affected individuals may also experience shortness of breath altered with a fast heart rate and passing out. Other symptoms include coughing up blood or fainting in some patients. To control and manage this condition, computed tomography can be done or at times, the ventilation-perfusion lung scan can be done. Blood work may also be carried out at the early stages of the disease to detect the clotting activity. Seizures These are signs of problems associated to the brain caused by sudden electrical activity within the brain causing sudden convulsions where a person shakes vigorously in a uncontrolled manner. A person experiencing seizure experiences loss of consciousness or confusion at times, others always experience rapid and abrupt eye movements accompanied by tongue biting or having uncontrolled and involuntary muscle spasms and a very funny tastes in the mouth. Some affected patients do clench their teeth or froth at the mouth and other also fall down always confused for fainting among other symptoms (Thurman etal., 2011). To manage the condition, a number of interventions can be put in place including drug therapy by use of generic drugs which are safe. Other anticonvulsant drugs can also be used though may be expensive at times. Some of the drugs used include; felbamate, gabapentin, phenobarbital and diazepam among others. Reference Leroy, H. A., Aboukas, R., Reyns, N., Bourgeois, P., Labreuche, J., Duhamel, A., Lejeune, J. P. (2015). Predictors of functional outcomes and recurrence of chronic subdural hematomas. Journal of Clinical Neuroscience, 22(12), 1895-1900. Thurman, D. J., Beghi, E., Begley, C. E., Berg, A. T., Buchhalter, J. R., Ding, D., ... Kroner, B. (2011). Standards for epidemiologic studies and surveillance of epilepsy. Epilepsia, 52(s7), 2-26.