Cultural Adaptations to Heat Stress in Dry Environments

Cultural Adaptations to Heat Stress in Dry Environments Human beings have long inhabited hot environments, and have developed several physiological mechanisms in order to deal with heat stress. We are exposed to two kinds of heat stress, environmental and metabolic, on a regular basis. Heat can be gained from the environment through radiation, convection and conduction, as well as created during the course of metabolic activity, which is compounded by exertion. The heat gained from these sources must be balanced by convective heat loss to the environment and through the evaporative cooling mechanisms (Hanna and Brown). Failure of these cooling mechanisms can result in heatstroke, a serious condition which can cause severe damage to the central nervous system (Bouchama and Knochel 2002). Over reliance on evaporative cooling can lead to another debilitating condition, dehydration. Hot desert environments, such as those found in North Africa and the Arabian Peninsula, are a perfect storm of stresses on human heat tolerance. High ambient temp eratures maximize heat gain from the environment, while severely reducing our ability to lose both environmental and metabolic heat by convective means. This causes an increase reliance on evaporative cooling in order to deal with rising body temperature. Increased sweating, combined with the lack of readily available water in desert climates severely increases the risk of dehydration. Populations native to desert areas exposed to the dual stresses of heat and lack of water employ a variety of cultural adaptations in order to buffer their natural thermoregulatory processes. Primary amongst these adaptations is the creation of a favorable microclimate through the use of clothing and architecture. (Hanna and Brown). Human heat tolerance can be summed up through the equation; Mb + Ma + S = E + R + K + C In this equation Mb and Ma represent heat generated by the body through basal metabolic activity and physical activity respectively. S is representative of the amount of heat stored by the tissues of the body. The right side of the equation represents environmental heat, with E, R, K, and C standing for evaporation, radiation, convection and conduction, the primary methods by which heat is lost to, or gained from, the environment. Evaporative cooling takes place as water secreted by the endocrine glands onto the skins surface undergoes a phase change and draws heat away from the body. Radiative heat gain is based on the transference of wide span length electromagnetic waves. Factors such as an objects temperature, reflectance and surface area, as well as those of objects around it, affect the net heat flow through this mechanism. While there is a positive gain of radiant heat by the human body from the sun under all circumstances, environmental conditions can greatly affect the magni tude of this gain. Heat flow by conduction functions in a manner similar to diffusion, between materials in contact with one another and from high to low heat areas. Environmentally, conductive heat exchange can occur between the body and the ground, while with-in the body it is the mechanism by which heat is transferred from the core to the surface of the skin. Convective heat flow occurs between an object and a moving fluid. The movements of the fluid can carry heat away from the body; this is the reason why a cool breeze can be so refreshing on a warm day. When ambient temperatures are at or above body temperature, however, convective currents can significantly increase heat load, sometimes beyond the bodys ability to compensate through other means (Hanna and Brown). Heat stroke is caused by an elevation of body temperature, usually due to failure of cooling mechanisms caused by exposure to high external temperatures, and is the most severe form of heat illness. Exertion can accelerate the onset of heat stroke by increasing metabolic heat production in active muscles. Symptoms of heat stroke include confusion and irrational behavior, weak pulse, elevation of breathing rate and unconsciousness. Severe cases can cause brain damage and organ failure, leading to death. An early symptom of the onset of heat illness is profuse sweating, caused by the bodys attempts to return to homeostasis. Salt loss through this excess perspiration can lead to muscle cramps, while the increase in water loss itself further elevates risk of dehydration (Heat Emergencies). Dehydration is the result of an imbalance between fluid loss and intake. Illness is a common cause of this condition, especially in children and the elderly. Reliance on sweating as a cooling mechanism without adequately rehydrating is another frequent cause of this condition. In hot dry environments, where increased sweating is required in order to maintain body temperature, dehydration is particularly common. Cases of Dehydration can randge from mild to severe, depending on the percentage of overall body water lost. Mild dehydration is easily treatable, and has relatively few long term consequences. Severe dehydration, if not treated quickly can result in damage to the central nervous system or death. Symptoms of dehydration include low blood pressure due to reduced fluid volume, elevated heart rate, dry mouth, low urine production, and in severe cases, lethargy and coma. One sign of dehydration is a reduction in skin turgor. Reduced water levels in the tissues cause skin to lose its elasticity, causing it to slowly return to position after being pinched upwards (. Cultural adaptations can serve as a buffer between the environment and the body, allowing survival in environments where physiological responses would be inadequate for or impede survival. Remarkable examples of this are seen in the populations of Northern Africa and the Arabian Peninsula. The populations native to these regions, such as the nomadic Bedouin and semi-nomadic Tuareg have developed specialized clothing and architecture that allow them to survive in some of the hottest, driest areas in the world, the Sahara and Arabian Deserts. The specialized material culture utilized by these groups facilitates the creation of a favorable microclimate around the body which allows them to maintain homeostasis without relying as strenuously on physiological mechanisms. A desert environment is defined by the KÃ ¶ppen-Geiger climate classification system as a region where the mean annual participation in mm is less than or equal to 5 Pth, which is defined by the following equation, In order to be designated as a hot desert, the region must also have a mean annual temperature greater than or equal to 18ÂÂ °C (Kottek et al). The Sahara Desert is the largest in the world, covering an area of 9,100,000 km2 across the breadth of North Africa. The central region of the desert receives less than 25 mm of rainfall annually, while regions on the eastern margin receiving as little as 5 mm annually. Rainfall is extremely sporadic when it does occur; a single storm sometimes accounts for multiple years worth of precipitation. The region is also amongst the hottest on earth, with temperatures exceeding 50ÂÂ ° C in the summer months. Diurnal variation in temperature can be considerable, the recorded maximum variation being 38ÂÂ ° C. Extreme winds are common in the Sahara, which when laden with dust make the environment even less hospitable. Underground aquifers occasionally break the surface and create oases amongst the otherwise barren landscape of stone plat eaus, salt flats and dunes (Berrahmouni and Burgess). The Arabian Desert is the dominant eco-region on the Arabian Peninsula, covering 1,851,300 Km2. Contained within the larger desert region is the vast Rubal-Khali, the Empty Quarter, which is the largest continuous area of sand in the world, stretching 500,000 km2. Salt flats and limestone cliffs are present in other regions of the desert. Average annual rainfall is less than 35mm, while temperatures average around 47ÂÂ ° C in summer. Temperatures drop significantly at night, sometimes reaching low enough for frost to form (Llewellyn-Smith). The Bedouin are a primarily nomadic pastoralist group located in the desert regions of the Arabian Peninsula and North Africa. Their subsistence is based around the raising of sheep, goats and camels, with limited dependence on seasonal agriculture in groups inhabiting regions with more predictable seasonal rains. The Bedouins traditional form of shelter is the bayt, a large rectangular tent constructed from sheeps wool. The roof is supported by a series of tall poles, while the walls of the tent are pinned onto the edge of the roof. The bottoms of the wall pieces are buried in the sand or pegged down, depending on the nature of the terrain. The interior is divided into sections, one for cooking and storage, the other for the entertaining of visitors. (Chatty) The tent is typically open along one of its long sides. This open wall, called the face of the tent or wej al bait, is on the leeward side. In the event of a sudden change in the wind, the back wall of then tent is unpinned and moved to what was formerly the face of the tent. In particularly hot weather parts of the side walls are unpinned to increase air flow throughout the tent. Carpets are sometimes employed to thicken the roof of the tent when the sun is stronger than usual (Dickson). When the wind is not particularly strong the side walls can be lowered entirely in order to maximize ventilation and cooling (Musil). The Bedouin traditionally dress in long, light garments that cover a majority of the bodys surface. For men, typical garments include a long tunic like shirt with wide sleeves that reaches to the ankles, loose trousers, a sleeveless cloak and a head cloth held in place by a woolen cord wound around the head. Womens clothing is similar, consisting of a long sleeved dress, black cotton over garment, loose trousers, cloak and various degrees of head covering, depending on the region the particular group hails from (Dickson). The Tuareg are a predominantly nomadic group inhabiting the nations of Mali, Algeria Niger and Libya. Different Tuareg groups practice widely different modes of subsistence, ranging from nomadic stock-breeding and trading to oasis gardening, although the latter is viewed with somewhat of a social stigma (Rasmussen). The Tuareg utilize a variety of both portable and non-portable dwellings, depending on their particular mode of subsistence. Nomadic Tuareg generally utilize a combination of mat and skin tents depending on regional conditions and availability of materials. Both of these tent forms follow the same basic layout, with the roof and sides suspended from a series of poles anchored in the substrate, while a wooden bed forms the floor of the structure. The particular arrangement of the poles varies significantly by region and preference, ranging from a small number of arches to a series of upright posts. The more sedentary groups amongst the Tuareg construct a variety of mud and mud coated stone houses, some of which are subterranean or semi-subteranean. These houses are typically rectangular, with small windows and flat roofs, although conical and domed forms are not uncommon in some regions of the Tuaregs territory. The most conspicuous aspects of traditional Tuareg clothing amongst both men and women are elaborate head coverings, taking the form of a veiled turban-like garment amongst men and a less elaborate head cloth for women. The mens veil, called a teguelmoust, is typically worn so that only a small space for the eyes is exposed. The amount of the face exposed varies considerably, however, depending on social circumstances. Mens garb consists of loose trousers and multiple sleeveless gandurah (a loose fitting cloak-like garment). Although sleeveless, the gandurah is loose enough that it typically extends below the hands. It is folded up over the forearms or shoulders when necessary to free the hands for manual labor. Womens costume includes either baggy trousers or a cotton skirt reaching to the knees, a gandurah similar to those worn by men but stitched higher on the sides, and a combination of shawl and headscarf made from the indigo dyed cotton popular amongst the Tuareg. This is often folded across the face for protection from the elements when riding or in the sun (Briggs). The primary benefit of clothing in a desert environment is its ability to minimize radiant heat gain by blocking solar radiation. Layers of clothing and air pockets caught between the layers insulate the body and prevent heat from being transferred to it. Baggy clothing allows for ventilation and air flow around the body, which encourage both convective and evaporative heat loss while still protecting the individual from environmental heat gain. Traditional populations in the regions of the Sahara and Arabian Deserts benefit from these concepts by dressing in layers of loose clothing that covers a majority of the body. A study performed by Henschel Hanson demonstrates the effectiveness of protective clothing in maintaining body temperature. This study demonstrated that acclimatized individuals wearing desert fatigues sweat 30% less than unclothed individuals when at rest, due to protection from radiant heat gain. Further benefit is seen in a lower core temperature and reduced heart rate relative to unclothed resting individuals. Clothing becomes less effective protection as metabolic heat production increases through exertion. The same study demonstrated that the benefits experienced by the individuals in desert fatigues were reduced by half (15% less than unclothed individuals) while engaged in physical labor (Hanna Brown). This reduction is due to an increased need to vent internally produced heat as compared to the benefit of preventing the uptake of environmental heat. The traditional clothing worn by the Bedouin and Tuareg is looser than typical fatigues, allowing for better circulating and larger pockets of insulating air, as well as providing superior protection to the head, neck and shoulders. This would likely increase the protective benefit gained by an individual at rest. The design of the clothing, allowing for more significant ventilation than desert fatigues, would likely allow an individual at work to still reap the maximum protective benefit w hile at the same time shedding metabolically generated heat. Another benefit of the head coverings worn by the Bedouin and Tuareg is their ability to protect the lungs and face from the desiccating effects of the hot dry winds. When pulled across the face, these veils can maintain a small pocket of air which is relatively humid compared to the environment, which greatly reduces the discomfort caused by exposure of the mucous membranes to the dry desert air (Briggs). Amos Rapoport describes in his book House Form and Culture several architectural traditions employed in hot dry climates that create favorable microclimates for human survival. Amongst these cultural adaptations are the use of stone and clay as building materials, small windows, use of courtyards, mutual shading and underground construction (Rapoport). Building materials such as stone or mud have a significant advantage in desert environments due to their high heat capacity. These materials function as a heat sink, absorbing radiant and convective heat during the day without significantly transferring heat to the shaded interior of the building. An added advantage to this style of architecture is its ability to hold onto heat gained over the course of the day, which can help deal with the low overnight temperatures common to deserts. A similar tactic is seen in underground construction. Dwellings constructed underground can take advantage of the tremendous heat capacity of the soil i tself to buffer interior temperatures from the outside environment. An example of this can be seen in the Matmata house found in parts of the Sahara. This structure takes the form of a series of subterranean rooms built around a central, pit-like courtyard. Upwards of 30 feet of earth shield the interior rooms from the heat of the sun, allowing the inhabitants to remain significantly cooler than they would be able to in an above ground structure (Rapoport). Surface Buildings in deserts are frequently constructed with few and small windows. This functions to reduce the amount radiant heat reaching the interior of the building directly. Placing windows high in the walls further serves this purpose. Permanent dwellings constructed by the Tuareg conform to these design standards; utilizing materials with a high heat capacity and minimizing opportunities for radiant and convective heat to enter the interior through windows or large doors (Nicholaison). The tents employed by the Bedouin cannot employ the techniques described above to the same degree, but instead function in a fashion similar to that of dessert clothing. Like the long robes worn by the Bedouin, the tent absorbs radiant heat, but prevents it from reaching the cooler microclimate within the tent. Attaching extra rugs to the roof of the tent in particularly hot weather furthers its ability to block and absorb radiant heat by increasing the amount of material able to take in heat and the distance that heat has to diffuse to reach the interior of the tent. The ability to adjust the walls of the tent in accordance with the need for ventilation and the strength of the wind also is a significant advantage. Ventilation can be adjusted in order to maximize air flow through the interior of the tent, and therefore cooling, while minimizing convective heating. Even with the back walls of the tent all the way up, enough air should penetrate through gaps in the panels to create a c urrent through the tent and out the front opening, removing hot air from the interior of the tent. The mat tents used by the Tuareg are thought to be vastly superior to the skin tents in the hot, dry season. They are better ventilated and, according to claims made by anthropologist Johannes Nicolaisen, the mat covering is not heated to any great extent by the sun (Nicolaisen, p. 375). Desert environments are extremely difficult conditions under which to live. They combine high ambient heat with a lack of water, pushing the human ability to maintain thermal homeostasis to its absolute limit. This taxing environment has encouraged the use of cultural adaptations to provide a buffer between the environment and the physiologic mechanisms necessary to keep cool. The primary areas in which these adaptations are applied are clothing and architecture. Loose, light clothing is utilized to block the absorption of radiant and convective heat from the environment, while at the same time creating an environment that maximizes convective and evaporative heat loss by creating a cycling zone of cool air next to the skin, allowing thermoregulation while only minimally engaging homeostatic mechanisms. Desert architecture utilizes high heat capacity materials and the earth itself as a heat sink to keep indoor temperatures at reasonable levels. The microclimate created through these cultural techniques provides a buffer zone that protects desert populations from the harmful effects of overtaxing their bodies cooling mechanisms and allows them to survive under some of the harshest conditions on earth.

The Future for Chicago Public Housing :: Sociology

The Future for Chicago Public Housing In big cities across America, the consensus is public housing doesn't work. And in Chicago, it's coming down. Chicago began using federal housing dollars to blow up or knock down high-rise public housing in 1993. The plan shifted into high gear when the city signed a $1.5 billion deal with the US Department of Housing and Urban Development. Under the plan for transformation, Chicago will destroy more public housing than any city in the country. There are families being pushed out of their homes, out of the city and the communities that they want to stay in. (Haney), Suzanne. "Street Wise" This is major impact on the city, from this comes segregation and the economy fails. Mayor Richard Daley and his administration promised people in Chicago affordable housing and now Daley has gone back on his word. Where has all that money gone that Mayor Daley has promised to millions of people who continue to struggle everyday? If you take a look around in Chicago there are more condos arising than housing for those really in need of the help. Mayor Daley and be Administration decided to take from people who are making over $75, 000 a year. They think by taking 30% of their money they will be able to help restore peoples housing to make it affordable. Why cant the government pay money to help people find an affordable house? Because affordability has become a national problem, causing housing prices to have gone up faster then people in Chicago can make money or can afford the cost of living. Hanney, Suzanne. ?Street Wise? November 17 2000 Secretary Martinez has put forth the effort. He awarded the largest amount of homeless assistants in the nations history more than $1.1 billion to fund thousands of local housing and service programs. in every state in the nation, This is part of the Bush administration focus on the resources on permanent housing and services. 95% of the residents are under Chicago Housing Authority (CHA) are on some kind of public assistance versus New York which only need 25% of public assistance. Chicago uses up this 95% of public assistance towards putting up expensive condos that range from $75,000-$100,000. They do this to try to compare up to New York's standards. Chicago?s Public Housing Projects, source The Economist, July 11, 1998. Mayor Daley goes on to say working together, all Chicagoans. We can make every window that looks out of the Chicago housing Authority (CHA) a window of opportunity. But that the key word here is opportunity, Mayor Daley has not giving any body under cha the opportunity for any thing. Mayor Daley takes these people homes from them and put up condo.

Example of Mathematics Lesson Plan for Bearing Topic

LESSON PLAN Date: 23 October 2012 (Tuesday) Time: 2. 30p. m until 3. 30 p. m. Class: 5 Science 1 Number of Pupils: 29 Subject: Mathematics Topic: Bearings Learning Area: Bearings Previous Knowledge: The students have learnt the four main compass directions in Geography Subject. Thinking Skills: Identifying, Calculating and Drawing. Teaching-learning Resources: Manila Card. Learning ObjectivesPupils will be taught to†¦ | Teaching and Learning Activities| Learning OutcomesPupils will be able to †¦ Remarks| 1 Understand the concept of bearing. | Introduce the eight main compass directions. | Draw and label the eight main compass directions: a) north, south, east, west, b) north-east, north-west, south-east, south west. | Vocabulary north-eastsouth-eastnorth-westsouth-westcompass anglebearing| 2 Use the concept of bearing. | 1 Show and calculate the compass angle of any direction. Examples :State the bearing of point P. Answer : 48? Answer : 180? + 60? 240? Answer : 180? â€⠀œ 40? = 140? Answer : 270? + 20? = 290? Answer : The bearing of  A  from  B  is 065?. The bearing of  B  from  A  is 245?. 2 Discuss the use of bearing in real life situations. For example, in map reading and navigation. Example : In Diagram 8, P, Q and R are three points on a horizontal plane. R lies to the east of P. The bearing of Q from P is 072?. The bearing of R from Q is A 162? B 198? C 288? D 342? | 1 State the compass angle of any compass direction. Draw a diagram which shows the direction of B to A given the bearing of B from A. 3 State the bearing of point A from point B based on the given information. 4 Solve problems involving bearings. | Point to noteCompass angle and bearing are written in three-digit form, from 000? to 360?. They are measured in a clockwise direction from north. Due north is considered as bearing 000?. For cases involvingdegrees and minutes, state in degrees up to one decimal place. |

Womens Right to Vote

Womens Right to Vote Free Online Research Papers Womens Right to Vote Helen, honey, Im finally home! said my husband, John. Greeting him with a smile on my face, I thought to myself I was home all day. After kissing me on the cheek, he said Wow that smells great! Whats for dinner? I pointed at the wooden table in the kitchen to the hot plate of beef stroganoff, his favorite. We set down and as he was telling me about his busy day at the Central Railroad, I nodded and grinned but my mind was somewhere else. John stopped for a minute to chew his food when I said, The presidential election is coming up, whom are you voting for? He gulped down his food and looked at me as if it was none of my business and said William McKinley of course! Why do you care? I replied Because Im an American citizen just like you and women deserve the same rights as men, that is first and foremost the right to vote! I said. Seeing how aggravated I was he slowly put his hand on mine and quietly said Honey, I just think it would be the best for you to be comfortable at home and not have to worry about any of this. Your place is at home. I shook my head, looked him straight in his green eyes and started tearing up. He had no idea how much this meant to me. I have to obey the laws, yet I dont have a voice in making them? Its an important factor in life that I dont have a part in just because of my sex? I can be a wife, mother, or sister but I dont deserve this role in our society? It was in this very moment something changed in my husband. I honestly think that the thought of women voting had never crossed his mind. It was as though he had simply accepted things as they were, without giving it a second thought. Though he was a very firm man, he cared for me very much and seeing me this distraught moved him. As we set silently my hair fell down my fists and my tears dropped down and all of a sudden I felt a warm hug from my husband. Hugging me he said â€Å"I’m sorry for being so blinded all this time, I know you’re right, we are in this together.† Research Papers on Women's Right to VoteThe Spring and Autumn19 Century Society: A Deeply Divided EraHip-Hop is ArtThe Fifth HorsemanTrailblazing by Eric AndersonBook Review on The Autobiography of Malcolm XComparison: Letter from Birmingham and CritoQuebec and CanadaThe Effects of Illegal ImmigrationPersonal Experience with Teen Pregnancy

THE LIFE AND WORKS OF CHARLES DICKENS essays

THE LIFE AND WORKS OF CHARLES DICKENS essays According to Edgar Johnson, in the novels of British writer Charles Dickens (1817-1870) "there is evidence that his troubled childhood left its mark upon the man and his works. The sense of power and the self-assertion, combined with an inadequacy for self-criticism, were perhaps compensations for the frustrations of his early years" (26). Generally considered as one of the greatest writers of the Victorian era, Charles Dickens' novels "are characterized by attacks on social evils, injustice and hypocrisy" (Books and Writers, Internet) which may be a reflection of his lower middle-class upbringing. In addition, Dickens is "probably the best known and most popular of British 19th century novelists," due to not only "the quality of his writing. . . but also to the widespread adaptation of his work for the stage and screen" (Catharton Authors, Internet). Though born on the South coast of England, Dickens was quite young when his parents brought him to live on the outskirts of London. His father was an ineffectual person with much debt that landed him in prison; his mother Elizabeth taught him to read early in life and some of the popular novels which he read were Tom Jones, The Vicar of Wakefield, Don Quixote and Gil Blas, some of which inspired him to write his first tale "Misnar" that was loosely based on the "Tales of the Genii" (Golden Books, Internet). At nine years of age, Dickens was apprenticed in a warehouse which was a very humiliating experience for such a sensitive, intelligent boy. After two years, better family fortunes enabled him to continue his schooling, but his real education came from his readings and wanderings in London along the Thames River. In 1827, Dickens was placed to a solicitor (a lawyer) and mastered shorthand and attended various sessions of the English court. He later became a re...

Article Review Example | Topics and Well Written Essays - 750 words - 12

Review - Article Example The major functions generally involve searching of the relevant literature for establishing the contact with the discipline for writing the relevant literature. At the time of searching of the literature, practitioners are faced with various challenges. In this regard, the practitioners search for the journals which are not accessible for everyone. Some journals are only accessible for key users, which are recognized as one of the big issues for the practitioners. The second problem relates to the accessing of the journals during the research. There are few prominent solutions, to this issue, such as many sites are provided for accessing the articles without any subscription charges and the research scholars are suggested to figure out a list of the relevant journals for the research purpose (Carr &Briggs, n.d.). The study is based upon the indirect behavioral observation. Thus, the study is qualitative in nature. Correspondingly, the research design has been established. The study can be referred to base on indirect observation as it involves reviewing the articles of others. The research design will be rated three as per the SMRS application (The National Autism Center, 2009). The measurement of the dependent variable is related to the availability of the subject related literature articles. The practitioners are engaged in exploring articles of others. Hence, they are dependent upon the availability of such accessible articles. The indirect observation also explains that the problems related to the unavailability of the accurate articles are the dependent variable of the research. On the basis of the given information, the writer will rate four by using the SMRS (The National Autism Center, 2009). The independent variable of the study is the subject of the research paper. On the basis of the indirect observation, it can be determined that approximately 80% of the literature review to be

Islam, Judaism And Christianity Essay Example | Topics and Well Written Essays - 1000 words

Islam, Judaism And Christianity - Essay Example Judaism not only can but does stand on its own. Judaism’s core beliefs in the Old Testaments are shared with Christianity. The two religions even believe in a messiah. The difference is Judaism rejects Jesus of Nazareth as that messiah, whereas Jesus is the long awaited savior in the Christian religion. The question becomes does one believe Jesus is the long awaited messiah? Christians believe so, normally without doubt. Judaism rejects that belief. Christianity has changed the world in the past two hundred years. America and most countries in the West have Christian leaders. This has influenced historical events. Cold War propaganda touted communist wanted to take over the world and get rid of religion all together. The evolution of anti-war movements and negotiations can be taken from Jesus’ teachings of peace. Instead of the Old Testament’s ‘eye for an eye’ like Judaism calls for, the death penalty has been rescinded in many countries and in parts of the United States. Finally, with the decadence of the past two hundred years, a messiah that forgives everything is quite appealing. It is more popular than Judaism’s demand that Biblical law be obeyed. Other events have been interpreted through Christian views in the past two hundred years. One example is the Holocaust.