Roman Aqueducts An Engineering Brilliance Essay Example For Students

Roman Aqueducts: An Engineering Brilliance Essay Transportation of water is a very important obstacle the world has taken on. Water is a necessity to live; therefore control of water in and out of towns has been going on for thousands of years. Many different ways of moving water from one spot to another have been tried over the years. One example is the building of dams, not only to generate electricity, but also to create an abundance of water that can be transported to farmers to water their crops. The water from the dam is sent through underground conduits, aqueducts, to its final destination. Aqueducts were used by Greeks, Assyrians, Babylonians, Persians and Egyptians for water transportation. These early civilizations provided the vision for the Roman Empire to perfect the use of the aqueduct. HISTORYIn 97 AD, Sextus Julius Frontinus, the city official in charge of the water supply, is recorded as saying:I ask you! Just compare this vast array of indispensable structures carrying so much water with the idle Pyramids or the world-famous but useless monuments of the Greeks. ( )In 97 AD, 300 gallons of water per person a day flowed into Rome through nine aqueducts. The Romans had succeeded in their vision of an aqueduct system supplying Rome with water. Many people, including Frontinus, thought that the Roman aqueduct system was the greatest invention in the world because of what it brought to the people of Rome. In the early days of Rome, the water supply came from the River Tiber. The Tiber, however is a very muddy river, and Romes sewer system also contaminated it. By the 4th century the Roman population was growing rapidly and Rome urgently needed an alternate water supply. In 312 BC the Roman Senate ordered Adile Appius Claudius to find a new source of water for the city . Claudius undertook the mission and started construction of the first aqueduct into Rome (Carr). Aqua Appia was successfully completed and over the next 500 years, ten more aqueducts were constructed in Rome. At completion of the last aqueduct into Rome, an estimated 38 million gallons of water flowed into Rome everyday! The Roman Empire also built many other aqueducts in Greece, Italy, France, Spain, North Africa, and Asia Minor. Even today some of the beautiful arches of the aqueducts can be seen. CONSTRUCTIONConstruction of the Roman Aqueduct started with finding a suitable source of water fairly close to the town that needed the water. This source usually came from underground springs for which the Romans had to search. After water was found, the aqueduct was commissioned to be built and a surveyor was hired to find the most practical route. The aqueducts gradient was usually around one foot drop per two hundred feet in length. By choosing the gradient and maintaining it along the entire length of the aqueduct, the water could be made to flow fast enough to ensure a good supply, yet not so fast that the force of the rushing water washed out the aqueducts and pipes (Myron). Getting this precise gradient required measurements by the surveyor. After the surveyor calculated the length of the aqueduct, and the overall fall, construction could then start. Underground AqueductsWork on the aqueduct would begin concurrently at various points along the route. Once a channel had been dug, a chorobate would be lowered into the trench to check the slope. The chorobate was a ten-foot long wooden trough with a long grove running down its middle where water was poured; the water indicated when something was level. Once the route was the right gradient the water channel was lined with concrete or a pipe was put into the ground. Underground aqueducts made up about 90% of the 313 total miles of aqueduct into Rome. Above Ground AqueductsWhen an aqueduct came to a valley, it was no longer possible to keep the required gradient underground; therefore the Romans designed a bridge like structure of arches that spanned over the valley. When you think of the Roman aqueducts, you think of these beautiful structures, but only about 10% of all aqueducts leading to Rome were above ground. These aqueducts were engineering feats. The structure was a series of arches that were built together. Sometimes, when a very high aqueduct was needed, there were three courses of arches, one on top of the other, with the arches becoming smaller toward the top. This stacking of arches was done because of stability reasons and it proved to work because some of the aqueducts are still standing today. The ArchOne of the Romans greatest engineering feat is the design of the arch. Before the Romans, the bridges that were built were usually a flat piece of stone spanned over a space between two upright supports. The problem with this design is that a heavy weight on the middle of the span put too much stress on the stone and broke it. The Romans solved this problem by designing the arch. When a heavy weight is on the arch, the stones compress into each other and into a solid foundation, thus making the structure stronger. The Romans used the arch in their designs of aqueducts, bridges, and buildings, many of which are still standing today. (BCIT) Materials The Romans were the first civilization to make a mortar that did not disintegrate when exposed to water. They found natural cement near the Italian town of Pozzuoli and mixed the cement with lime, sand, and water to form the mortar. The mortar was used by Roman Engineers in aqueducts, as a binder in piers and arches, and for foundations. In the arch, stones were held together with the mortar. The arch sat on a solid foundation and the stones were stacked up and mortared together so the axial forces between the stones would transfer the load into the foundation. Therefore the arch could withstand a large amount of force. The top of the aqueduct was lined with cement and covered by stones to protect the aqueduct from contamination and poisoning from enemy troops. (BCIT) PUBLIC WORKSWhen the water reached the city, it was held in tanks. The tanks were then tapped to 1200 public fountains, eleven large-scale public baths, 867 smaller baths, and two artificial lakes. The aqueducts of Rom e created the original public works system. Water was regulated and taxed to private and public homes. The 38 million gallons of water that went through Rome everyday had to go somewhere, so a sewer system was created to get rid of the excess waste. The sewer in some places was large enough for a good-sized boat to travel through. The excess water from the aqueducts ran through the sewer and into the Tiber River, completing the public works cycle. (Hamblin). .u4b479d87a4b055a45a927421ac3a3c9d , .u4b479d87a4b055a45a927421ac3a3c9d .postImageUrl , .u4b479d87a4b055a45a927421ac3a3c9d .centered-text-area { min-height: 80px; position: relative; } .u4b479d87a4b055a45a927421ac3a3c9d , .u4b479d87a4b055a45a927421ac3a3c9d:hover , .u4b479d87a4b055a45a927421ac3a3c9d:visited , .u4b479d87a4b055a45a927421ac3a3c9d:active { border:0!important; } .u4b479d87a4b055a45a927421ac3a3c9d .clearfix:after { content: ""; display: table; clear: both; } .u4b479d87a4b055a45a927421ac3a3c9d { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u4b479d87a4b055a45a927421ac3a3c9d:active , .u4b479d87a4b055a45a927421ac3a3c9d:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u4b479d87a4b055a45a927421ac3a3c9d .centered-text-area { width: 100%; position: relative ; } .u4b479d87a4b055a45a927421ac3a3c9d .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u4b479d87a4b055a45a927421ac3a3c9d .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u4b479d87a4b055a45a927421ac3a3c9d .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u4b479d87a4b055a45a927421ac3a3c9d:hover .ctaButton { background-color: #34495E!important; } .u4b479d87a4b055a45a927421ac3a3c9d .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u4b479d87a4b055a45a927421ac3a3c9d .u4b479d87a4b055a45a927421ac3a3c9d-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u4b479d87a4b055a45a927421ac3a3c9d:after { content: ""; display: block; clear: both; } READ: The Atomic Bomb and its Effects on Post-World War EssayCONCLUSIONSCivil Engineering has been greatly influenced by the Romans. Their civilization was the first to recognize what could be done with water, and they utilized their knowledge to create aqueducts to transport that water. Their engineering feats are still remarkable today, as many bridges and aqueducts are still standing utilizing the arch and cement. Many of their ideas are still put to use today. Aqueducts are still used to transport water, even though Californias extensive aqueduct system which yields 3 billion gallons of water per day, the Romans accomplished their system 2000 years before a comparable system was created (Crystal). The arch was also a brilliant design as it was used as the main structure for bridges until the 17th century. Even today the arch is still a reliable source for bridge building. The Romans were ahead of their time with their brilliant aqueducts. Engineering Essays

Is its Writing Essay Sample Band Really Worth It?

Is its Writing Essay Sample Band Really Worth It?Many people take an ielts writing essay sample band class and end up getting a C or D for their grade. Although they may not have received the grade they expected, they can still benefit from taking one in their own busy lives. There are so many people who feel that taking the ielts writing essay sample band class will make them look stupid or worse, will bring down their grade when they know that many people are capable of doing well.A great deal of people consider the ielts writing essay sample band class as a waste of time and effort. They believe that all they are really doing is wasting their money. The best way to avoid this is to give yourself plenty of practice by reading the various topics from different angles and then getting to write your essay. I am here to tell you that this method can actually make it easier for you to learn your subject and give you the chance to look smart and study hard.You have to get yourself an iel ts writing essay sample band so that you can begin to memorize all the tips and tricks of how to work on this course. You should be able to create a list of the key points that you want to remember to review for your students and give them a good idea of what you want them to learn. Then when they come to take the exam, you can help them with the study habits you want them to follow. They will be able to help you put into practice the various strategies that you have taught them and it will also help you to learn the key points of the course.One of the ways to get more done in your writing essay sample band is to review all the tips and hints that you have included in the syllabus. The advantage of this is that you get to stay sharp throughout the course and your students get the opportunity to see you in action. You can even pick up on certain areas of your students' studies that you do not understand.Using a highly technical and easy text book as a guide does not mean that you are being lazy or careless. If you can be fastidious about using the right term in the right context, then this will make a difference in the way your students feel about you and your knowledge of the subject.To reinforce the fact that it is a good use of time and money to spend money on a class like this, you can take some extra practice tests with the help of the free assignments that you get. As long as you take a few of these to begin with, you will have more practice exercises which will help you in any way possible. This will also prove that the ielts writing essay sample band course is worth the investment.Taking ielts writing essay sample band can be a great way to teach and learn about the subject and get yourself updated on the latest on-line information. As long as you can look smart and able to remember all the useful tips and hints, then you will do just fine. What a great way to improve your grades!

NCO Respect free essay sample

Commissioned officers are direct representatives of the President. The President uses commissions as legal instruments to appoint and exercise direct control over qualified people who act as his legal agents and help him carry out duties. The Army retains this direct-agent relationship with the President through its commissioned officers. The commission serves as the basis for a commissioned officer’s legal authority. Commissioned officers command, establish policy, and manage Army resources. Warrant officers are highly specialized, single-track specialty officers who receive their authority from the Secretary of the Army upon their initial appointment. However, Title 10 USC authorizes the commissioning of warrant officers (WO1) upon promotion to chief warrant officer (CW2). These commissioned warrant officers are direct representatives of the President of the United States. They derive their authority from the same source as commissioned officers, but remain specialists in their field. Warrant officers can and do command detachments, units, activities, and vessels as well as lead, coach, train and counsel subordinates. We will write a custom essay sample on NCO Respect or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page As leaders and technical experts, they provide valuable skills, guidance, and expertise to commanders and organizations in their particular field. Noncommissioned officers, the backbone of the Army, train, lead, and take care of enlisted soldiers. They also provide advice to officers in every aspect of unit operations. NCOs often represent officers and DAC leaders in their absence. They ensure their soldiers, along with their personal equipment, are prepared to function as effective unit and team members. While commissioned officers command, establish policy, and manage resources, NCOs conduct the Army’s daily business. Junior enlisted soldiers are where the rubber meets the road. Junior enlisted soldiers perform their duties to standard AND to the best of their ability. This means perfroming individual tasks identified by first line supervisors based on the unit’s mission essential task list (METL). All soldiers must be able to do those individual tasks to standard because that is where every successful operation begins—at the individual task level. Junior enlisted soldiers can seek help from first-line supervisors for problems they are unable to solve. Like every soldier in the Army, junior enlisted soldiers have a duty to obey the lawful orders of superiors. Even junior enlisted soldiers can make on-the-spot corrections—they shouldn’t walk by a deficiency without tactfully correcting the problem. That’s professionalism. Department of the Army civilians are members of the executive branch of the federal government and are a vital part of the Army. DACs fill positions in staff and base sustaining operations that might otherwise have to be filled by officers and NCOs. Senior DACs establish policy and manage Army resources, but they do not have the authority to command. The complementary relationship and mutual respect between the military and civilian members of the Army is a long-standing tradition. Since the Army’s beginning in 1775, military and civilian roles have stayed separate, yet necessarily related. Taken in combination, traditions, functions, and laws also help clarify duties of military and civilian members of the Army. Specified duties are those related to jobs and positions. Directives such as Army regulations, Department of the Army (DA) general orders, the Uniform Code of Military Justice (UCMJ), soldier’s manuals, Army Training and Evaluation Program (ARTEP) or Mission Training Plan (MTP) publications, and Military Occupational Specialty (MOS) job descriptions specify the duties. They spell out what soldiers must do and the standards they must meet. Directed duties are not specified as part of a job position or MOS or other directive. A superior gives them orally or in writing. Directed duties include being in charge of quarters (CQ) or serving as sergeant of the guard, staff duty officer, company training NCO, and nuclear, biological and chemical (NBC) NCO where these duties are not found in the unit’s organizational charts. Implied duties often support specified duties, but in some cases they may not be related to the military occupational specialty (MOS) job position. These duties may not be written but implied in the instructions. They’re duties that improve the quality of the job and help keep the unit functioning at an optimum level. In most cases, these duties depend on individual initiative. They improve the work environment and motivate soldiers to perform because they want to, not because they have to. Responsibility is the legally established and moral obligation a soldier assumes for his own actions, accomplishments and failures. Leaders also assume responsibility for the actions, accomplishments, and failures of their units and decisions. Above all, the leader is responsible for accomplishing his assigned missions. Then, he is responsible for his soldiers’ health, welfare, morale, and discipline. The leader is responsible for maintaining and employing the resources of his force. In most cases, these responsibilities do not conflict. But sometimes they do. For example, SPC Hull has requested a three day pass, Friday through Sunday, because an old friend is visiting for the weekend. But Friday the company is going to the range to qualify on individual weapons. There is no other range time scheduled for the next three months. If such a conflict cannot be resolved, accomplishing the mission must come first. In the example, SPC Hull’s commander disapproves the pass. Related to responsibility is accountability. This is the requirement to answer to superiors (and ultimately the American people) for mission accomplishment, for the lives and care of assigned soldiers, and for effectively and efficiently using Army resources. It also includes an obligation to answer for properly using delegated authority. Leaders are accountable for what they do or fail to do. For example, SSG Calhoun must explain to the platoon leader and platoon sergeant why three tires on one of her squad’s vehicles are not inflated to the air pressure specified in the technical manual. Soldiers account for their actions to their fellow soldiers or organization, their leaders, the Army and the American people. Officers, NCOs, and DACs lead other officers, NCOs, junior enlisted soldiers, and DACs and help them carry out their responsibilities. Commanders set overall policies and standards, but all leaders guide, assist, and supervise subordinates, who assist and advise their leaders. Mission accomplishment demands that officers, NCOs and DACs work together to advise, assist and learn from each other.

Should You Take the ACT or the SAT

Should You Take the ACT or the SAT SAT / ACT Prep Online Guides and Tips If you're in high school, you may be wondering whether you should take the SAT or the ACT. In general, the two tests have gotten much more similarsince the SAT was revamped in 2016,but there are still a few differences that may sway you towards one or the other. In this guide, I've outlined some of the key factors you should keep in mind when deciding which test to focus on and created a quiz that can help you determine which test will be better for you. The first thing you should do is take anACTandSAT practice testand compare your scores. We have a conversion table where you can easily see how your SAT and ACT scores stack up. If you score much higher on one test than the other, I recommend that you study for and take the test you did better on. If your scores are pretty close and you're still not sure which exam to take, keep reading. Next, I recommend checkingwhether one exam or the other is required at your school. It's easier to study for a test you're already familiar with, so if your school requires either the ACT or the SAT, you'll want to seriously consider sticking to the requiredtest. Now, let's move on to the key reasons you might want to go with each test, starting with the SAT. Feature Image: jimflix!/Flickr Take the SAT If You... #1: Panic When Faced With Time Limits One of the most noticeable differences between the redesigned SAT and the ACT is the amount of time per question- you have much more of it on the SAT. This doesn't actually make the SAT easier,since its actual questions tend to be harder, but it does mean thatthe ACT feels like more of a time crunch than the SAT. As such, doing well on the ACTrequires calm in the face of time limits. If you struggle to move through material quickly or tend to panic, you'll likely do better with the SAT. #2: Can’t Stand the Idea of Not Getting to Every Question On the SAT, you have enough time to get to most of the questions, as long as you use it wisely. On the ACT, you probably won't finish all of the sections unless you're scoring a 30 or above. If you have an obsessive need to answer every single question, you should stick tothe SAT. #3: Have a Hard Time Spotting Details When You Read SAT reading questions almost always give you the line number where you can find the relevant information. Even if they don't give you the exact location, the questions are in order, so it's rarely difficult to find information in the passage. ACT reading questions, on the other hand, are randomlyordered and frequently don't give line numbers, so finding specific details in the passage is one of the trickiest parts. If you struggle with retaining or finding details, you will probably prefer the SAT. #4: Struggle With Geometry ACT math has over three times as many geometry questions as the math section on the redesigned SAT. Plus, for the ACT, you need to memorize all the formulas, while on the SAT you're given them at the beginning of the section. If you have a very hard time with geometry, consider taking the SAT. #5: Want to Encounter as Little Science as Possible The ACT has a science section; the SAT does not. If you dislike science or struggle with quantitative thinking, you will probably prefer the SAT. The redesigned SAT does include science questions in each of its threesections, so there's no way to escape science entirely. Nonetheless, struggling withscience will have less of an effect on your score onthe SAT than it willon the ACT. #6: Excel at Writing Analytical Essays in English Class The SAT essayasks you to read and analyze a persuasive essay, much like you might for aclass assignment. If you like English class, you'll almost certainly prefer the SAT essay to the ACT one. That being said, neither essay affects your overall score, so a preference for one or the othershouldn't play a major role in your decision between the two tests. Want to learn more about the SAT but tired of reading blog articles? Then you'll love our free, SAT prep livestreams. Designed and led by PrepScholar SAT experts, these live video events are a great resource for students and parents looking to learn more about the SAT and SAT prep. Click on the button below to register for one of our livestreams today! Next up: the six reasons you might prefer the ACT. Remember you'll have to study forwhichever test you choose. (Image: m00by/Flickr) Take the ACT If You... #1:Struggle With Vocabulary Although it no longer has sentence completion questions, the redesigned SATstill tests more challenging vocabulary on both the reading and writing sections. It also has harder passages on the reading section and more vocab questions overall. The ACT is the better test if you want to avoid higher-level words like "satiated" and "apprehensive" and older passages with challenging language. #2: Can't Always Explain How You Know an Answer Is Correct One of the big changes to the SAT is the addition of evidence questions on the reading section. These questions ask you to point to the part of the passage that supports your answer to another question- #14 is an example: Evidencequestions aren't as novel as they might seem at first, since, in theory, you should always be able to point to the support for your answer in the passage. But if this is a skill you really struggle with, consider taking the ACT instead. #3:Are Intimidated by Doing Math Without a Calculator The SAT has a no-calculator section, so if the idea of doing math without a calculator has you completely freaked out, you may want to stick to the ACT. However, the no-calculator section really doesn't require any complicated calculations. In fact,all of the math questions on both testscanbe done without a calculator, though some are rather challenging. The question is really whether you feel comfortable doing some basic calculations by hand. If not, the SAT will be a challenge for you. #4: Prefer That Different Topics Be Tested in Different Sections One of the goals of the SAT redesign is to integrateimportant skills across all three sections, so there's more overlap between the different sections than on the ACT. One key example of this new policy is the presence of quantitative questions in the reading and writing sections of the SAT. If you'd prefer to avoid this kind of concept mixing, stick with the ACT. #5: Have a Solid Grasp of Experimental Design If you like science, and especially if you have a good understanding of how experiments are built and know the difference between independent and dependentvariables, consider taking the ACT. The ACT asks a lot ofquestionsabout experimental design whilethe SAT new science questions are solely focused on reading charts and graphs. A strong grasp of these concepts will give you a considerable leg up on the ACT. #6: Like to Give Your Opinion The ACT essay is all about arguing for your own point (unlike the SAT essay, which is about analyzing someone else's argument). If you enjoystating your opinion and marshaling examples to back it up, then you will probably prefer the ACT essay. Remember, however, that you may not need to take the essay at all and that, even if you do, it doesn't affect your overall score. You can choose your own adventure in studying. (Image: Nathan Penglington, photo byColin Ross/Flickr) Quiz: Should You Take the ACT or the SAT? In case you're still on the fence about which test you want to focus on, I've created a handy quiz. It sums up all of the ideas above (except those relating to the optional essays) in one easy-to-use chart. To use it, just go through and check"yes" or "no" for each question. Then tally up your answers and give yourself one point for each "yes." Scroll down for an explanation of what your score means. Question Yes No Do you perform well under time pressure? Are you okay with not answering every question on a test? Do you struggle to explain why you think an answer is correct? Do you have a hard timewith high level vocab words? Can you spot details ina passage without reading it closely? Do you dread doing math without a calculator? Do you excel at geometry? Do you prefer each topic be tested separately? Do you understand experimental design? Do you like science? Let's go through what your score means: 1-3: You're an SAT person! If you answered "no" to most of the questions, you'll probably find the SAT more your style. You don't mind slightly harder questions as long asyou don't have to rush and don't have to cover too much material. 4-7: You can do either! If you answered "no" and "yes" roughly the same amount, you will probably find the tests equally approachable. If you're willing to put in the time, try taking one practice test for each and see if you have a strong preference. 8-10: You'll likethe ACT! If you answered mostly "yes," then you're more of an ACT person. You don't mind moving quickly, memorizing material, or answering questions about science. What's Next? For more info on the differences between the two tests, check out our full breakdown or these comparison charts. Wondering how well you'd score on the SAT or ACT?Take a practice test to find out! Check out our links to free and official ACT and SAT practice tests and get started. Want to improve your SAT score by 160 points or your ACT score by 4 points?We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now:

English Literature and History Learning journal. Subjects of Queen Essay

English Literature and History Learning journal. Subjects of Queen Elizabeth - Essay Example Her 45 year rule is considered as the ‘golden era’ of England (Crown, 2009). The Queen was proficient and had the huge political foresight. Her selfless attitude towards her kingdom is depicted through her decision of not getting married. As getting married to a foreign king would make England vulnerable to the foreign policies and would easily be drawn into the political turmoil. The Elizabethan era was the one of the most promising period of England’s history. The phase was noted to be filled with both knowledge and prosperity of the kingdom. The Queen was one of the best rulers of her times and reflected huge amount of care for subjects. Even though she was not very widely accepted by her subjects who considered her a protestant, the kindness that Elizabeth I portrayed for her subjects during her reign of almost a half century was irreplaceable and commendable. Furthermore, Elizabeth I handled the situation of financial turmoil and religious conflicts that her predecessor has left very tactfully (Stump & Felch, 2009). With this concern the essay presents the rich understanding on the historical portrayal of Queen Elizabeth I. Furthermore, the essay provides considerable insights about different aspects of the society during her reign. Queen Elizabeth I was one of the most knowledgeable and sound queens among her siblings. The Queen was fluent in six languages and had a huge urge of learning. Elizabeth I faced massive uncertain situations during the early years of her life. She was secluded from her family and had spent her life in her half brothers home. This seclusion from the normal life could not make her distressed and she devoted her initial years of life and adulthood in nurturing the different literatures (Guy, 1995). These initial years of upbringing has influenced her ruling periods to a greater extent. The initial phase of her life and during her adolescence, the Queen portrayed a selfless character and hugely depicted her

Chronic Pancreatitis Term Paper Example | Topics and Well Written Essays - 3000 words

Chronic Pancreatitis - Term Paper Example General Description Chronic Pancreatitis (CP) is a heterogeneous, progressive disorder of the pancreas characterized by a spectrum of symptoms pain, inflammation, diabetes mellitus, and pancreatic damage leading to significant loss of both endocrine and exocrine functions of the pancreas (Witt and associates, 2007; DiMagno & Dimagno, 2006). Pathology involves fibrosis in the pancreatic parenchyma that manifests irregularly. Other organs in the vicinity are also affected as consequence of the disease that may commence as an individual or a group of symptoms resulting from functional impairment of pancreas. The major clinical symptom of the disease is recurring or persistent pain within the abdomens. The chief cause of CP in the western world is alcohol abuse leading to alcoholic calcific pancreatitis (ACP). The other form of CP known as tropical calcific pancreatitis (TCP) prevalent in tropical countries is of uncertain etiology (Lee, 2011). Based on the risk factors CP is classified by the TIGAR-O (Toxic-metabolic, Idiopathic, Genetic, Autoimmune, Recurrent and severe acute, Obstructive) classification system (Nair tet al., 2007). Figure 1: Anatomy of the pancreas (http://www.britannica.com/bps/media-view/68636/1/0/0) Pancreas: Normal Physiology Pancreas is a retroperitoneal structure in the upper abdomen that can broadly be divided into head, body, and tail (figure 1). A major portion of pancreatic tissue comprises of acini (80%) that are responsible for the exocrine functions of the pancreas. Groups of aciniform spherical lobules that are interspersed with connective tissue. The central ducts of each lobule in which the secretions of the surrounding acinar cells accumulate, join to extralobular ducts that finally drain into the main pancreatic duct. The main pancreatic duct carrying the secreted digestive enzymes enters the hepatopancreatic ampulla along with bile duct. At the duodenal papilla, the enzymes enter the duodenum (Adda et al., 1984). The endocrine functions of the pancreas are performed by the richly vascularized islets of Langerhans. The islets of Langerhans comprise of beta, alpha and delta cells that secrete hormones insulin, glucagon, somatostatin respectively. The most abundant beta cells (73-75%) are centrally located and are surrounded by alpha cells (18-20%) and delta cells (4-6%). The rich vascularization allows for the transfer of hormones from the islets while the specific arrangement of the alpha, beta and delta cells allows paracrine regulation of hormones. Thus high concentrations of the insulin secreted by the central beta cells inhibit glucagon release from the peripheral alpha cells. The venous blood flow from the islets of Langerhans reaches the hepatic portal vein, rendering the liver the prime target for the impact of pancreatic hormones. The rich innervations of the pancreas ensure the release of several neurotransmitters in the pancreas that regulate the release and concentrations of hormones (Case, 200 6). During normal physiology, in the basal state, the secreted pancreatic fluid is mildly alkaline comprising a few proteins. Gastric distension and acid production during eating stimulate duodenal S cells causing the release of secretin. Under the influence of the secretin, a large quantity of the bicarbonate-rich watery liquid or the hydraulic secretion is released from the ductal cells of the smaller ducts.  

Language Acquisition Device

Language Acquisition Device In 1965 the linguist Noam Chomsky put forward the idea that language was innate, and suggested that childrens language acquisition was supported by a Language Acquisition Device (LAD). Other linguists and psychologists, however, have their own theories of child language acquisition, three of which base the development of language on interaction with caregivers, on cognitive development, and on imitation and reinforcement respectively. At first glance, it seems that the different theories of child language acquisition contradict each other, that it would be impossible for all five theories to have an element of truth in them. When, however, you look at the theories in more detail, you realise that the way in which children acquire language is likely to be a result of the five different theories working together. By describing language as innate, Chomsky was suggesting that children are born with an internal knowledge of language, that the rules of language are inside their brains from birth, so that when they begin to speak, they will have a pre-existing knowledge of grammatical rules. This essay will demonstrate that while Chomskys LAD is undoubtedly present in children, the other theories of child language acquisition also play a role in the development of childrens language; none can be disregarded as being untrue. In 1986, Chomsky added to his theory of language innateness by putting forward the idea that the Language Acquisition Device contained a Universal Grammar, a set of basic rules of grammar that characterise all languages. This explains the fact that children from all over the world pass through similar stages, at similar ages, in the acquisition of language, despite vast cultural differences. By 5 years of age, most children have a good grasp of the basic rules of their own language. This provides strong evidence for the existence of a LAD, as if language were not innate, children from different countries and backgrounds would surely pick up different aspects of language in different orders, and all children, even those from the same backgrounds, would acquire language at different rates. Further evidence for the existence of a Language Acquisition Device comes from what was termed s-structures (surface structures) and d-structures (deep structures) (Chomsky, 1957, 1982). Different languages have different surface structures (the actual phrases used in a sentence), but they all share the same deep structures, reflecting the sentences meaning. The fact that children understand deep structures without having to be actively taught about them suggests that language is innate: children have an inborn understanding of grammatical concepts, understanding that the order of words within a sentence is important. The grammatical errors that children make during the process of acquiring language, known as overgeneralisation, also suggest that language is an innate module, thereby providing evidence for the existence of a Language Acquisition Device. Overgeneralisation occurs, for example, when children apply the past tense -ed inflection to irregular verbs such as go. Children obviously wouldnt hear an adult saying goed, which suggests that children have an inbuilt knowledge of grammatical rules: they know that to form the past tense they have to use the -ed suffix, but they arent yet aware of irregular verbs. Evidence for grammatical overgeneralisation by children comes from an experiment carried out by Brown and Bellugi in 1964, in which the early speech of two children was analysed. The -ed past tense inflection was used for irregular verbs such as come (comed) and grow (growed). Further overgeneralisation occurred when forming plurals: nouns such as sheep and tooth were made plural by addi ng the -s inflection (sheeps and tooths). Again, the two children had learnt that to make a noun plural you used the -s inflection, but they were not yet aware of nouns which didnt follow the normal grammatical rule. The fact that not all children are exposed to Child Directed Speech provides further evidence for the innate nature of language. The cultures of the islands which lie in the South Pacific Ocean, for example, believe that such ways of speaking actually interfere with a childs language development. Infants in countries such as Samoa and Papua New Guinea, therefore, do not hear modified forms of language: all they hear is their native language in all its complexity. Despite the fact that the only language they are exposed to is the standard, unaltered form of their native language, infants in such countries pick up language at much the same rate and just as quickly as infants who are exposed to simplified forms of language, who are exposed to Child Directed Speech. This points clearly to the fact that language is innate, as if it wasnt, children in such countries would arguably acquire language at a later age, as a result of them not being exposed to simplified forms of language. A final piece of evidence for the existence of a Language Acquisition Device is the fact that language is specific only to humans. No other species spontaneously develops language in the way that humans do. This fact, coupled with the relative speed and ease with which children acquire their first language, provides substantial evidence for the existence of a LAD, especially as language is far too complex to be taught completely from scratch. Despite all of this evidence supporting the existence of a Language Acquisition Device, there are some factors which would throw the existence of the LAD into doubt. One such factor is the fact that feral children, along with children who have suffered extreme cases of abuse and neglect fail to master language, beyond the basics, even when taught by specialists. One such case is that of Genie (Curtiss, 1977). Up to the age of 13, from the age of approximately 20 months, Genie was kept in an isolated room with practically no human contact. Upon being rescued, Genie successfully learnt vocabulary, although she failed to understand the rules behind grammar, and as a result was only able to master three-word utterances as a result of the lack of attention and interaction she received throughout her infancy and childhood. This situation has been found to be the case with feral children, and with other victims of extreme child abuse. The inability to master grammatical rules, and therefore to speak in grammatically correct and complete sentences, can be explained by the Critical Period Hypothesis (Lenneberg, 1967), which theorises that language learning is easiest before a certain age. Combining the fact that feral children and abused children fail to master anything but the basics of language with the Critical Period Hypothesis provides evidence against the existence of a LAD. If language were innate, as Chomsky suggested, such children would be able to acquire language, however old they were when rescued, as it would simply be a matter of learning the vocabulary; they would have the grammatical rules already in place. The fact that they are unable to suggests that something else is required: this is where the other theorists of child language acquisition come in. One such alternative theory of childrens acquisition of language is the Behaviourist Account, associated with the psychologist B.F. Skinner. Skinner, 1957, suggested that children acquire language through a process known as operant conditioning. In a linguistic sense, this means that when a child uses language correctly, in terms of both the lexis and the grammar, they are rewarded in various ways. Due to these rewards, children are motivated to repeat the behaviour, thereby shaping their language and ensuring that it develops successfully. Another theory which goes against that set out by Chomsky is the Cognition Theory. Jean Piaget, a developmental psychologist, believed that cognitive development (the development of mental abilities and skills) was the overriding influence on the development of language, with language being neither innate nor learned passively. Piagets theory focuses on the precursors of early language, such as gestures and facial expressions, as Piaget claimed that in the first two years of life, the childs intellectual skills rely on sensori-motor experiences such as seeing, hearing and touching, as opposed to on words and images. While Piaget agreed with Chomsky in the sense that children develop a set of rules, he believed that rather than being innate, they came instead from a wider cognitive system, whereby children form schemas to help explain events in their lives, and then they are able to talk about them. Piagets concept of Object Permanence helps to support his cognition theory, in turn pr oviding evidence against the existence of a Language Acquisition Device. Before 18 months of age, infants are egocentric, as they cant mentally process the concept that something can exist outside of their immediate surroundings. By the time they are 18 months old, however, they have developed a sense of object permanence, realising that objects exist all of the time, even when the infant cant see them. The development of object permanence coincides with a substantial increase in vocabulary: if, as Chomsky suggested, language was innate and children possessed a LAD, object permanence wouldnt take such a long time to develop, as they would have a sufficient level of development to understand that an object couldnt and wouldnt just disappear. A further theory which helps to question the existence of Chomskys Language Acquisition Device is that of the psychologist Jerome Bruner. Bruners interactionist theory stresses the role of linguistic interaction from caregivers in a childs language development. This theory doesnt completely disprove the existence of the LAD; rather it suggests that something else is needed. Bruner suggested that children have a Language Acquisition Support System (LASS), whereby caregivers support their childs acquisition of language in social situations. A final theory which provides evidence against the existence of the Language Acquisition Device is that put forward by the psychologist Lev Vygotsky: the Socio-Cultural theory. The main tenet of this theory is that both social interaction and experiencing different social and cultural contexts are important for the development of language. Two significant factors which contribute to language development were identified: Private Speech (when a child talks aloud to itself, providing evidence that they are thinking for themselves) and the Zone of Proximal Development (ZPD) which occurs when a child needs the help of a caregiver in order to interact. The caregiver will either respond for the child, or will try to encourage a response from the child, both of which provide the child with a model to apply to similar situations in the future. This essay has discussed both evidence for and against the existence of Language Acquisition Device as proposed by Chomsky. The existence of the LAD has been challenged not only by other theories of child language acquisition but also by individual cases of feral and abused children. As the evidence set out in the essay suggests, the existence of Chomskys LAD cannot be disproved completely, as arguing that it didnt exist would put too many things down to coincidence, examples being that children the world over pass through similar stages of language development, and that children instinctively apply grammatical rules to irregular verbs and nouns, leading to overgeneralisation. You cant, however, simply disregard the work of other psychologist and linguists, as they all carried out their research to prove their hypotheses. Therefore, it is likely that all five of the theories mentioned play a part in childrens acquisition of language: while language may be innate, it develops alongsid e a childs cognitive development and children require input and encouragement from their caregivers in order for their use of language to develop fully. To conclude, no one theory of child language acquisition can be said to be wholly responsible for childrens acquisition of language, it is different aspects of each theory working together which make language learning such an impressive feat; this neither proves nor disproves the existence of Chomskys LAD.