Smithsonian Tropical Research Institute in Barro Colorado, Republic of Essay

Smithsonian Tropical Research Institute in Barro Colorado, Republic of Panama - Essay Example The goals, achievements and some of the exotic flora and fauna of the institute have also been described. History and Current Status of STRI, Barro Colorado The history of STRI begins with the construction of the Panama Canal during which the Barro Colorado Island was formed (National Research Council). The damming of the Chagres River for the construction of the Panama Canal led to a rise in its water levels, causing the formation of the Gantun Lake. Following this, a small mountain about 476 feet high was isolated from the mainland, thus forming an island that was named the Barro Colorado Island (The Smithsonian Institution). James Zetek is one among the many scientists who foresaw the importance of setting this island aside for scientific research. In 1923, the Governor of Canal Zone designated the island as a biological reserve, and a research laboratory was set up collectively by the Smithsonian Institution, universities and private organizations for the purpose of investigating tropical flora and fauna (The Smithsonian Institution). Smithsonian’s fourth Secretary, Charles Doolittle Walcott, initiated a massive survey of the Panama Canal Zone (National Research Council). By 1946, the Barro Colorado Island became an integral part of the Smithsonian Institution. ... In 1966, its name was changed to the Smithsonian Tropical Research Institute. Its scope was expanded to other parts of the tropics and marine science centers were also established on the Pacific and Atlantic coasts of the Panama (The Smithsonian Institution). Barro Colorado, in 1979, was declared a Nature Monument in compliance with the terms of the Convention for Nature Protection in the Western Hemisphere, 1940, and under the Torrijos-Carter Treaty (The Smithsonian Institution). Panama took STRI’s facilities under its custodianship and granted it the status of an International Mission. The Panama Canal Treaties were signed between Panama and STRI’s host nation. STRI signed an agreement with the Interoceanic Region Authority (ARI), formalizing its custodianship of the Barro Colorado Natural Monument before the expiration of the Panama Canal Treaties. In 1997, the institute came into an agreement with the Government of the Republic of Panama for continuing its research activities. Up to the present day, STRI has been host to scientists from all over the world. Barro Colorado is now one of the most studied tropical areas and boasts of about 102 mammal species, 381 bird species, and 1,316 plant species ranging over an area of 1,500 hectares and containing a vast network of trails (The Smithsonian Institution). Long-term studies on biology and natural history are being conducted on both terrestrial and marine field stations that are equipped with high-end laboratories along with dormitories. STRI has expanded its scope to other tropical areas and research is now conducted throughout Asia, Africa and Latin America. Every year, about 250 to 300 scientists visit STRI at Barro Colorado from all over the world (The Smithsonian Institution). Goals and Achievements of the

Greek Mythology Essay Essay Example for Free

Greek Mythology Essay Essay There are many similarities and differences between Greek myths and what Genesis says. One example is the creation of man and the universe. Another example is how the first woman was created and what she was meant for. The last example is the Greek’s account of the flood compared to the Genesis account. The universe was created by thunder according to Greek myth. But in reality it was created by the voice of God saying in Genesis, Let there be, and it was. The word of God was distorted in the Greek myth by saying everything was created with thunder when really Gods voice was like thunder as it says in Job 40:9 Do you have an arm like Gods, and can your voice thunder like his?. Over time, the bible saying Gods voice sounds like thunder may have been perceived as just thunder in the Greek account. This is what may have caused the Greek myths of creation to become so distorted. There are also some similarities and differences between the Genesis and Greek account of the creation of woman. The first woman, Eve, was created out of Adams rib as Genesis says in chapter 20 verse 22 Then the Lord God made a woman from the rib he had taken out of the man, and he brought her to the man. Genises also states that Eve was a gift from God to Adam, however, the Greek account states that the first woman, Pandora, was a punishment by God. These are just some of the distortions between the Genises account and the Greek myth. There are many similarities and differences between what the Genises account states and what the Greek account states about the flood. In the Greek account, Zues got angry at the world because of humanitys sins and wanted to destroy it. He was going to destroy the world with a thunder bolt when he dicided to flood it instead because otherwise heaven would light on fire. Really God never debated how to destroy the world, he just instantly choose to do it with a flood as it says in Genises 6:17, I am going to bring floodwaters on the earth to destroy all life under the heavens, every creature that has breath of life in it. Everything on earth will perish. God told Noah to build an ark and to put all living creatures, male and female, onto the ark for he was going to flood the earth. However, in the  Greek account Zues never warned humanity of the flood, he just had Posiden flood it and Hades create earthquakes. Two humans found refuge on a mountain that the waters didnt reach. These are just some examples of the distortions between Greek myth and the Genises account. In conclusion, the Greek account of the creation of man, how the first woman was created and what she was meant for, and their account of the flood compared to the Genises account all have many similarities and differences. One thing that may have caused these distortions of the Genises account is the bibles use of figurative language and people perceiving it the wrong way.

Osteoporosis Essay -- essays research papers

Osteoporosis Osteoporosis is a significant health problem that affects more than 25 million women in the United States and potentially 200 million worldwide. This disease is characterized by diminishing the structure of the skeleton (particular the "spongy" bone). This results in an increased risk of fracture. Osteoporosis develops silently over a period of years, eventually progressing to a point where a fracture can easily occur causing pain and disability. This disease is characterized by low bone mass and structural worsening of your bones, leading to bone fragility. There is an increased chances of damaging the hip, spine, and wrist . Twenty-five million Americans are affected by Osteoporosis, making it a major public health problem. 80% of those affected by osteoporosis are women. One out of every two women and one in five men have an Osteoporosis-related fracture. By age 75, one third of all men will be affected by osteoporosis. While osteoporosis is often thought of as an older person's disease, it can strike at any age. Osteoporosis is responsible for 1.5 million fractures annually, including: -more than 300,000 hip fractures -500,000 vertebral fractures -200,000 wrist fractures Certain some people are more likely to develop Osteoporosis than others. These factors can increase your chances of getting osteoporosis. -A family history of fractures in elderly women -Use of certain medications -Chronically low calcium intake -Thin and/or small bones -An ina...

Do You Prefer to Eat Out or at Home Essay

Some people prefer to eat at food stands or restaurants while others prefer to prepare and eat food at home. I have a predilection of eating food at food stands and restaurants because there is a lot of variety of food, the food is cooked and prepared more professionally and it helps in giving a change in the atmosphere. In restaurants, there is so much variety of food to choose from while at home it is always the same kind of food. Whenever I go to a restaurant, I can choose my food from burgers to Asian food. In a restaurant, one can order whatever one likes without having to go through the trouble of cooking. When I feel like eating a burger or an Italian dish or some complex dish, all I have to do is go to a restaurant. On the other hand, at home there is no diversity of food and I have to eat the same types of food everyday. Food cooked and prepared at home is never as tasty as food in restaurants. In restaurants food is made very efficiently. Once I ate pizza at home but it was no way near the delicious pizza at the restaurants. Not only that, when my sister eats at home she always complains that either the food is too spicy or not salty enough. In contrast, at food stands and restaurants the food is perfect with the right amount of spice and salt. Food in restaurants is delicious and cannot be compared to the food made at home. Eating everyday at home becomes very drab and dull. Furthermore it takes away the opportunity for an outing. However, eating in a restaurant changes the dreary environment to a cheerful and delightful one. When my sister and I eat at home, we lose our appetite at times because of eating the same thing daily in the same place. But eating in a restaurant gives us the opportunity to explore new places and new foods. I prefer food at food stands and restaurants more than food prepared food at home because it is tastier, I can eat whatever I please and I can have some outing. Without restaurants, there would be no enjoyment and the world would lose the opportunity of experiencing and exploring all sorts of foods from all over the world.

Healthy Eating Habits and Lifestyle Essay

In today’s American society, many individuals have developed unhealthy eating habits. A study done in 2012 states fifty-two percent of polled Americans thought that doing their taxes was easier than trying to figure out how to eat healthy. There are many things that people look at as hassles to healthy eating rather than looking at the big benefits healthy eating has on someone. Many people think of these issues when they think of healthy eating the cost, the availability of the food, that it is â€Å"hard†, they do not want to diet, and so on. Changing the eating habits of an individual is not as hard as someone would think. Even though eating healthy can save a persons life, Many people would rather look at the â€Å"hassles† to healthy eating because it is easier to do rather than making a big change to their lifestyle. One of the most common things most individuals say is that eating healthy cost too much and the food that is healthy is not always available. Yes during some seasons fruit and vegetables are a little higher in cost. The fruits and vegetables individuals purchase do not have to be fresh produce, they can buy frozen fruits and vegetables during the expensive seasons. Do not buy canned fruits and vegetables though because they are soaked in sodium, preservatives, and high fructose corn syrup. Sure buying fruits and vegetables involves more work than grabbing something from a drive-thru window or even opening a package and cooking it. However, how much work is being sick? Having to go to the doctor and having to miss school or work because eating unhealthy lead to health issues like heart disease, obesity, and possibly even cancer. Yes eating fast food is very convenient and cheap, but eating fast food is more likely to lead to health problems in the future. Eating healthy along with exercise can completely change an individual’s health and wellness. Healthy eating promotes good health that reduces the risk of chronic diseases like heart disease, high blood pressure, type 2 diabetes, obesity, and even cancer. Even with the health risks people often make excuses to why they do not eat healthy. â€Å"I  am too busy.† â€Å"I do not know how.† â€Å"I do not want to diet†, These are three of the most common answers individuals say when asked why most people do not eat healthy. Everyone has a busy schedule but if everyone wants to continue to be busy and be able to do the things they like to do, they have to be healthy. Knowing how to eat healthy really is common knowledge. One does not have to go on a strict diet to see healthy changes. When eating healthy do not eat out, only take in little sugar, cut out trans fat, cut out â€Å"nonfat† and â€Å"lowfat† products, and high processed foods. Also when eating healthy having a low-carbohydrate intake is a wonderful thing. Also when eating healthy, lower your carbohydrate intake. A low-carbohydrate intake minimizes sugar and starches and replaces them with foods that are rich in protein and healthy fats. Look for â€Å"real food† which is food that humans had available throughout evolution. Stay away from processed, unnatural foods that have artificial chemicals, these foods can cause you to get sick and fat. Yes most people have cravings for pizza, chips, and other things everyone knows is â€Å"unhealthy†. An individual does not want to deprive themselves of what they want, cheating is common when it comes to eating healt hy, individuals need allow themselves one cheat day a week to eat whatever they want. Though with healthy eating can seem hard at times, it comes with big lifestyle changes that are more that worth it. Eating healthy can make substantial changes to someones health, wellness, and lifestyle. Eating healthy has more benefits than anything even exercise. Someone can exercise everyday of the week and still be considered unhealthy because of what they eat. According to MyDebtDiary, as long as long as an individual eats healthy for eighty percent of the time, an individual can indulge in their favorite foods the other twenty percent of the time. Nate Miyaki gives an example, â€Å"Of nine training sessions and thirty- five meals or snacks geared toward body composition improvement a week, that works out to about 20% accounted to physical activity and 80% accounted to diet.† Participating in regular exercise is very important but does not mean someone should eat unhealthy. Eating unhealthy causes damage to an individuals insides. When someone eats healthy they find themselves less tired and they also find that they have less health issues than someone that eats unhealthy. When an individual eats better they feel better. Put good in, get good out. So the better an indivi dual eats the better, the more energy they have, the more  motivation they have, and they feel better as a whole. Within a week of eating healthy an individual can begin to feel better on the inside. When an individual makes the change to eating healthily they will notice that they feel better and have more energy. There are more ways to eat healthier without having to diet at all. A great food guide for an athlete to follow is the Canada’s Food Guide. According to the guide an individual needs about sixty percent carbohydrates, fifteen to twenty percent protein, and twenty to thirty percent fat in their daily diet. Healthy eating is more than just about what an individual eats and puts on their plate. Healthy eating is also about how an individual thinks about food, what they eat, and how they eat. When eating it is important to slow down while eating and realize that the food that an individual puts into their body is nourishment, not as something to scarf down in between work and kids practices. It is always good to try and eat with other people whenever possible. There are many social and emotional benefits to eating with others, especially for children, and it also allows individuals to model healthy eating habits. Another thing that most individuals forget about is how bad eating i n front of the television and computer is. Eating in front of the television and computer often leads to overeating. One of the biggest causes of weight gain is sleep deprivation. Sleep is a necessity to recovery to feel good, and a good nights sleep has a wide variety of positive health outcomes. The positive health outcomes range from a healthier body weight and a lower stress level. When an individual has â€Å"sleep debt† they can not recover it by sleeping more from night to night. Having a set sleep schedule should be a habit and it is crucial to a healthy lifestyle. When an individual is not exhausted or tired it is easier for sleep patterns to change and those changes can disrupt their schedule. Going to bed and waking up at the same time every day allows an individual’s body to create a rhythm for a healthy metabolism and energy patterns. When one is having trouble going to sleep there are many things one can do. Removing stimulating items like phones, television, and computers an hour before bed because the screens can over stimulate and distract an individual and make it ha rder for them to fall asleep. Consuming caffeine after three in the afternoon stimulates the nervous system and also affects sleeping patterns. An individual also should avoid large meal before bed. The importance of sleep should not be ignored. Sleep allows the body and brain to shut down and recover which is crucial for possible health conditions. Sticking to a regular sleep routine allows individuals to wake up with more energy and feel less fatigue throughout the day. When an individual begins to eat healthy, the less natural it feels to reach for a cupcake or a slice of pizza when they get hungry. One should not deprive themselves or force themselves to eat healthy, but an individual should simply make a conscious decision of identifying and respecting what feels best for their body in the long run. When individuals eat healthy, they physically feel good and also feel good mentally as well. Individuals who eat healthy mentally have more energy to go out and do things that care and matter to them. Making the decision to practice healthy eating habits has such significant effects on an individuals in so many ways. Everyone should take action and begin to maintain a healthy lifestyle choices as much as possible. Most people need motivation to change, gain motivation from others, keep a diary, and talk to others when tempted to indulge in unhealthy choices. Eating healthy is not all about losing the ability to enjoy favorite foods. It is about gaining things that will have a life long effect. Eating healthy leads to a longer life, the ability to enjoy real, natural foods, a healthy sense of self esteem, and pleasure of having respect for the body and all that it does. References 11 Facts About American Eating Habits. (n.d.). Retrieved October 27, 2014, from https://www.dosomething.org/facts/11-facts-about-american-eating-habits Belval, L. (2013, December 5). HEALTHY HUSKY: Healthy eating habits. Retrieved October 27, 2014, from http://search.proquest.com.ezproxy.apollolibrary.com/docview/1465901308?pq-origsite=summon Braverman, J. (2014, January 26). Illnesses Caused by Bad Diet. Retrieved October 27, 2014, from http://www.livestrong.com/article/84174-illnesses-caused-bad-diet/ Cho, M. (n.d.). Five Tricks I Used to Beat My Unhealthy Eating Habits. Retrieved October 27, 2014, from http://lifehacker.com/five-tricks-i-used-to-beat-my-unhealthy-eating-habits-1252241279 Conclusion: Living a Healthy Diet for the Rest of Your Life – Intent Blog. (2009, October 6). Retrieved October 27, 2014, from http://intentblog.com/conclusion-living-healthy-diet-rest-your-life/ Daily, I. (2013, February 1). Healthy Eating Habits Acquired. Retrieved October 27, 2014, from http://search.proquest.com.ezproxy.apollolibrary.com/docview/1370960686?pq-origsite=summon How to Eat Healthy, Lose Weight and Feel Awesome Every Day. (n.d.). Retrieved October 27, 2014, from http://authoritynutrition.com/how-to-eat-healthy/ Isacks, K. (n.d.). Weight Loss and Food Diaries | MyNetDiary. Retrieved October 27, 2014, from http://www.mynetdiary.com/the-new-80-20-rule-a-long-held-rule-in-the-dieting.html Kunz, M. (2013, December 18). Does Exercise Offset Unhealthy Eating? Retrieved October 27, 2014, from http://www.livestrong.com/article/548179-does-exercise-offset-unhealthy-eating/ Miyaki, N. (n.d.). The 80/20 Rule of Fitness Nutrition. Retrieved October 27, 2014, from http://nat emiyaki.com/2011/03/24/the-8020-rule-of-fitness-nutrition/ Sandilands, M. (1999, September 9). Abnormal eating habits ruin health. Retrieved October 27, 2014, from http://search.proquest.com.ezproxy.apollolibrary.com/docview/244805140?pq-origsite=summon Smith, T. (2011, December 21). Top 10 Reasons Why We Don’t Eat Healthy. Retrieved October 27, 2014, from http://patch.com/california/carlsbad/bp–top-10-reasons-why-we-dont-eat-healthy#.VEGgj75H21I Traister, J. (2011, January 17). Pros and Cons for Healthy Food Choices. Retrieved October 27, 2014, from http://www.livestrong.com/article/358976-pros-and-cons-for-healthy-food-choices/

WEBER Surname Meaning and Family History

WEBER Surname Meaning and Family History Weber is an occupational surname given to one skilled in the ancient craft of weaving, from the from the Middle High German word wà «ber,  a derivative of weben, meaning to weave.  The Weber surname is sometimes Anglicized as Webber or Weaver. Weber is the 6th most common German surname. It is also frequently found as a  Czech, Hungarian, Polish or  Slovenian surname.  WEBB and  WEAVER are English variants of the name. Surname Origin: German Alternate Surname Spellings:  WEEBER, WEBBER, WEBERE, WEBERER, WAEBER, WEYBER, WEBERN, VON WEBER, VON WEBBER Famous People with the WEBER  Surname Max Weber  -  19th-century German sociologist and one of the founders of modern sociologyCarl Maria von Webber -  German composer, conductor, pianist and  guitaristConstanze Weber - wife of Wolfgang Amadeus MozartAlfred Weber - German economist, geographer and sociologistJohn Henry Weber - American fur trader and explorerJoseph Weber - American physicistLudwig Weber -  German Protestant pastor and social reformer- German-born physician, best known for first describing the brain condition which carries his name (Webers syndrome) Where is the WEBER Surname Most Common? According to surname distribution from Forebears, WEBER is the 3rd most common surname in Germany. It is also very common in Switzerland, where it ranks 7th, and Austria, where it is the 19th most prevalent last name. While Weber is common throughout Germany, WorldNames PublicProfiler indicates it is most frequent in southwestern Germany, in the regions of Rheinland-Pfalz, Saarland and Hessen. Weber is also a very common surname in Gussing, Austria.   Genealogy Resources for the Surname WEBER Meanings of Common German SurnamesUncover the meaning of your German last name with this free guide to the meanings and origins of common German surnames. Weber  Family Crest - Its Not What You ThinkContrary to what you may hear, there is no such thing as a Weber  family crest or coat of arms for the Weber surname.  Coats of arms are granted to individuals, not families, and may rightfully be used only by the uninterrupted male line descendants of the person to whom the coat of arms was originally granted. Weber Y-Chromosome DNA  Surname ProjectWEBERs from all over the world are participating in this group DNA project in an attempt to learn more about Weber family origins. The website includes information on the project, the research done to date, and instructions on how to participate. WEBER  Family Genealogy ForumFree message board is focused on descendants of Weber  ancestors around the world. FamilySearch - WEBER  GenealogyExplore over 5 million results from digitized  historical records and lineage-linked family trees related to the Weber  surname on this free website hosted by the Church of Jesus Christ of Latter-day Saints. WEBER  Surname Mailing ListFree mailing list for researchers of the Weber  surname and its variations includes subscription details and a searchable archives of past messages. DistantCousin.com - WEBER  Genealogy Family HistoryExplore free databases and genealogy links for the last name Weber. GeneaNet - Weber  RecordsGeneaNet includes archival records, family trees, and other resources for individuals with the Weber  surname, with a concentration on records and families from France and other European countries. The Weber Genealogy and Family Tree PageBrowse genealogy records and links to genealogical and historical records for individuals with the Weber  surname from the website of Genealogy Today. - References: Surname Meanings Origins Cottle, Basil.  Penguin Dictionary of Surnames. Baltimore, MD: Penguin Books, 1967. Dorward, David.  Scottish Surnames. Collins Celtic (Pocket edition), 1998. Fucilla, Joseph.  Our Italian Surnames. Genealogical Publishing Company, 2003. Hanks, Patrick and Flavia Hodges.  A Dictionary of Surnames. Oxford University Press, 1989. Hanks, Patrick.  Dictionary of American Family Names. Oxford University Press, 2003. Reaney, P.H.  A Dictionary of English Surnames. Oxford University Press, 1997. Smith, Elsdon C.  American Surnames. Genealogical Publishing Company, 1997. Back to  Glossary of Surname Meanings Origins

Free Essays on The 7 Habits Of Highly Effective People

Book Review on The 7 Habits of Highly Effective People In this review you will read about the book The 7 Habits of Highly Effective People, written by Stephen R. Covey. The book will talk about seven habits that are portrayed. These habits are believed to be necessary in order to go through powerful personal change to better oneself, and to help with solving personal as well as professional problems. The following habits are discussed throughout the book, be proactive, begin with the end in mind, put first things first, think win/win, seek first to understand then be understood, synergize, and sharpen the saw. Each one of these habits being unique and having its own goal to reach. Covey discusses habit one as being proactive. This habit is the very beginning in a series of powerful lessons to better oneself, from this habit the rest will follow. This particular habit discusses the principles of personal vision, it discusses how self-awareness enables us to stand apart and examine the way we see ourselves. Self- awareness is our map of the basic nature of mankind. With this habit we also have the social mirror, which explains how humans react according to society. This habit emphasizes pro-activity, how we as human beings are responsible for our own lives. Under this, it explains how reactive people are driven by feelings, circumstances, conditions, the environment, and also how they are driven by carefully considered, selected and internalized values. Covey states that all problems fall into three categories; direct control, indirect control and no control. He theorizes the circle of influence and explains how we are all a part of it; he also gives vi suals in the forms of diagrams. These visuals make the circle or influence easy to understand. Over all, habit one of being proactive starts us in a good path, leading us to think about the principles of our personal visions. The second habit is to begin with the end ... Free Essays on The 7 Habits Of Highly Effective People Free Essays on The 7 Habits Of Highly Effective People Book Review on The 7 Habits of Highly Effective People In this review you will read about the book The 7 Habits of Highly Effective People, written by Stephen R. Covey. The book will talk about seven habits that are portrayed. These habits are believed to be necessary in order to go through powerful personal change to better oneself, and to help with solving personal as well as professional problems. The following habits are discussed throughout the book, be proactive, begin with the end in mind, put first things first, think win/win, seek first to understand then be understood, synergize, and sharpen the saw. Each one of these habits being unique and having its own goal to reach. Covey discusses habit one as being proactive. This habit is the very beginning in a series of powerful lessons to better oneself, from this habit the rest will follow. This particular habit discusses the principles of personal vision, it discusses how self-awareness enables us to stand apart and examine the way we see ourselves. Self- awareness is our map of the basic nature of mankind. With this habit we also have the social mirror, which explains how humans react according to society. This habit emphasizes pro-activity, how we as human beings are responsible for our own lives. Under this, it explains how reactive people are driven by feelings, circumstances, conditions, the environment, and also how they are driven by carefully considered, selected and internalized values. Covey states that all problems fall into three categories; direct control, indirect control and no control. He theorizes the circle of influence and explains how we are all a part of it; he also gives vi suals in the forms of diagrams. These visuals make the circle or influence easy to understand. Over all, habit one of being proactive starts us in a good path, leading us to think about the principles of our personal visions. The second habit is to begin with the end ...

Overview of the Poem Beowulf

Overview of the Poem Beowulf Below is a summary of all the events that transpire in the Old English epic poem, Beowulf. Beowulf is considered the oldest surviving  poem in the English language.   A Kingdom in Peril The story begins in Denmark with King Hrothgar, the descendant of the great Scyld Sheafson and a successful ruler in his own right. To display his prosperity and generosity, Hrothgar built a magnificent hall called Heorot. There his warriors, the Scyldings, gathered to drink mead, receive treasures from the king after a battle, and listen to scops sing songs of brave deeds. But lurking nearby was a hideous and brutal monster named Grendel. One night when the warriors were sleeping, sated from their feast, Grendel attacked, butchering 30 men and wreaking devastation in the hall. Hrothgar and his Scyldings were overwhelmed with sorrow and dismay, but they could do nothing; for the next night Grendel returned to kill again. The Scyldings tried to stand up to Grendel, but none of their weapons harmed him. They sought the help of their pagan gods, but no help was forthcoming. Night after night Grendel attacked Heorot and the warriors who defended it, slaying many brave men, until the Scyldings ceased fighting and simply abandoned the hall each sunset. Grendel then began attacking the lands around Heorot, terrorizing the Danes for the next 12 years. A Hero Comes to Heorot Many tales were told, and songs are sung of the horror that had overtaken Hrothgars kingdom, and word spread as far as the kingdom of the Geats (southwest Sweden). There one of King Hygelacs retainers, Beowulf, heard the story of Hrothgars dilemma. Hrothgar had once done a favor for Beowulfs father, Ecgtheow, and so, perhaps feeling indebted, and certainly inspired by the challenge of overcoming Grendel, Beowulf determined to travel to Denmark and fight the monster. Beowulf was dear to Hygelac and the elder Geats, and they were loath to see him go, yet they did not hinder him in his endeavor. The young man assembled a band of 14 worthy warriors to accompany him to Denmark, and they set sail. Arriving at Heorot, they petitioned to see Hrothgar, and once inside the hall, Beowulf made an earnest speech requesting the honor of facing Grendel, and promising to fight the fiend without weapons or shield. Hrothgar welcomed Beowulf and his comrades and honored him with a feast. Amidst the drinking and camaraderie, a jealous Scylding named Unferth taunted Beowulf, accusing him of losing a swimming race to his childhood friend Breca, and sneering that he had no chance against Grendel. Beowulf boldly responded with the gripping tale of how he not only won the race but slew many horrible sea-beasts in the process. The Geats confident response reassured the Scyldings. Then Hrothgars queen, Wealhtheow, made an appearance, and Beowulf vowed to her that hed slay Grendel or die trying. For the first time in years, Hrothgar and his retainers had cause to hope, and a festive atmosphere settled over Heorot. Then, after an evening of feasting and drinking, the king and his fellow Danes bid Beowulf and his companions good luck and departed. The heroic Geat and his brave comrades settled down for the night in the beleaguered mead-hall. Though every last Geat followed Beowulf willingly into this adventure, none of them truly believed they would see home again. Grendel When all but one of the warriors had fallen asleep, Grendel approached Heorot. The door to the hall swung open at his touch, but rage boiled up within him, and he tore it apart and bounded inside. Before anyone could move, he grabbed one of the sleeping Geats, rent him into pieces and devoured him, slurping his blood. Next, he turned to Beowulf, raising a claw to attack. But Beowulf was ready. He sprang up from his bench and caught Grendel in a fearsome grip, the like of which the monster had never known. Try as he might, Grendel could not loosen Beowulfs hold; he backed away, growing afraid. In the meantime, the other warriors in the hall attacked the fiend with their swords; but this had no effect. They couldnt have known that Grendel was invulnerable to any weapon forged by man. It was Beowulfs strength that overcame the creature; and though he struggled with everything he had to escape, causing the very timbers of Heorot to shudder, Grendel could not break free from the grip of Beowulf. As the monster weakened and the hero stood firm, the fight, at last, came to a horrific end when Beowulf ripped Grendels entire arm and shoulder from his body. The fiend fled, bleeding, to die in his lair in the swamp, and the victorious Geats hailed Beowulfs greatness. Celebrations With the sunrise came joyous Scyldings and clan chiefs from near and far. Hrothgars minstrel arrived and wove Beowulfs name and deeds into songs old and new. He told a tale of a dragon slayer and compared Beowulf to other great heroes of ages past. Some time was spent considering the wisdom of a leader placing himself in danger instead of sending younger warriors to do his bidding. The king arrived in all his majesty and made a speech thanking God and praising Beowulf. He announced his adoption of the hero as his son, and Wealhtheow added her approval, while Beowulf sat between her boys as if he were their brother. In the face of Beowulfs grisly trophy, Unferth had nothing to say. Hrothgar ordered that Heorot be refurbished, and everyone threw themselves into repairing and brightening the great hall. A magnificent feast followed, with more stories and poems, more drinking and good fellowship. The king and queen bestowed great gifts on all the Geats, but especially on the man who had saved them from Grendel, who received among his prizes a magnificent golden torque. As the day drew to a close, Beowulf was led off to separate quarters in honor of his heroic status. Scyldings bedded down in the great hall, as they had in the days before Grendel, now with their Geat comrades among them. But although the beast that had terrorized them for more than a decade was dead, another danger lurked in the darkness. A New Threat Grendels mother, enraged and seeking revenge, struck while the warriors slept. Her attack was barely any less terrible than those of her son had been. She grabbed Aeschere, Hrothgars most valued advisor, and, crushing his body in a deadly grip, she raced away into the night, snatching the trophy of her sons arm before she escaped. The attack had happened so quickly and unexpectedly that both the Scyldings and the Geats were at a loss. It soon became clear that this monster had to be stopped, and that Beowulf was the man to stop her. Hrothgar himself led a party of men in pursuit of the fiend, whose trail was marked by her movements and Aescheres blood. Soon the trackers came to the ghastly swamp, where dangerous creatures swam in a filthy viscous fluid, and where Aescheres head lay on the banks to further shock and appall all who beheld it. Beowulf armed himself for an underwater battle, donning finely-woven mail armor and a princely golden helm that had never failed to thwart any blade. Unferth, no longer jealous, lent him a battle-tested sword of great antiquity called Hrunting. After requesting that Hrothgar take care of his companions should he fail to defeat the monster, and naming Unferth as his heir, Beowulf plunged into the revolting lake. Grendels Mother It took hours for Beowulf to reach the lair of the fiends. He survived many attacks from awful swamp creatures, thanks to his armor and his swift swimming skill. At last, as he neared the monsters hiding place, she sensed Beowulfs presence and dragged him inside. In the firelight the hero beheld the hellish creature, and wasting no time, he drew Hrunting and dealt her a thunderous blow to her head. But the worthy blade, never before bested in battle, failed to harm Grendels mother. Beowulf tossed the weapon aside and attacked her with his bare hands, throwing her to the ground. But Grendels mother was swift and resilient; she rose to her feet and gripped him in a horrible embrace. The hero was shaken; he stumbled and fell, and the fiend pounced upon him, drew a knife and stabbed down. But Beowulfs armor deflected the blade. He struggled to his feet to face the monster again. And then something caught his eye in the murky cave: a gigantic sword that few men could wield. Beowulf seized the weapon in a rage, swung it fiercely in a wide arc, and hacked deep into the monsters neck, severing her head and toppling her to the ground. With the death of the creature, an uncanny light brightened the cave, and Beowulf could take stock of his surroundings. He saw Grendels corpse and, still raging from his battle; he hacked off its head. Then, as the toxic blood of the monsters melted the blade of the awesome sword, he noticed piles of treasure; but Beowulf took none of it, bringing back only the hilt of the great weapon and Grendels head as he began his swim back. A Triumphant Return So long had it taken for Beowulf to swim to the monsters lair and defeat her that the Scyldings had given up hope and gone back to Heorot- but the Geats stayed on. Beowulf hauled his gory prize through water that was clearer and no longer infested with horrible creatures. When he finally swam to shore, his cohorts greeted him with unrestrained joy. They escorted him back to Heorot; it took four men to carry Grendels severed head. As might be expected, Beowulf was hailed once more as a great hero upon his return to the splendid mead-hall. The young Geat presented the ancient sword-hilt to Hrothgar, who was moved to make a serious speech exhorting Beowulf to be mindful of how fragile life could be, as the king himself knew all too well. More festivities followed before the great Geat could take to his bed. Now the danger was truly gone, and Beowulf could sleep easy. Geatland The next day the Geats made ready to return home. More gifts were bestowed upon them by their grateful hosts, and speeches were made full of praise and warm feelings. Beowulf pledged to serve Hrothgar in any way he might need him in the future, and Hrothgar proclaimed that Beowulf was fit to be king of the Geats. The warriors sailed off, their ship filled with treasure, their hearts full of admiration for the Scylding king. Back in Geatland, King Hygelac greeted Beowulf with relief and bid him to tell him and his court everything of his adventures. This the hero did, in detail. He then presented Hygelac with all the treasures Hrothgar and the Danes had bestowed upon him. Hygelac made a speech recognizing how much greater a man Beowulf had proven himself to be than any of the elders had realized, though they had always loved him well. The King of the Geats bestowed a precious sword on the hero and gave him tracts of land to govern. The golden torque Beowulf had presented him would be around Hygelacs neck the day he died. A Dragon Awakes Fifty years went by. The deaths of Hygelac and his only son and heir meant that the crown of Geatland passed to Beowulf. The hero ruled wisely and well over a prosperous land. Then a great peril awoke. A fleeing slave, seeking refuge from a hard master, stumbled upon a hidden passageway that led to the lair of a dragon. Sneaking quietly through the sleeping beasts treasure hoard, the slave snatched a single jewel-encrusted cup before escaping in terror. He returned to his lord and proffered his find, hoping to be reinstated. The master agreed, little knowing what price the kingdom would pay for his slaves transgression. When the dragon woke up, it knew instantly it had been robbed, and it vented its fury on the land. Scorching crops and livestock, devastating homes, the dragon raged across Geatland. Even the kings mighty stronghold was burnt to a cinder. The King Prepares to Fight Beowulf wanted revenge, but he also knew he had to stop the beast to ensure the safety of his kingdom. He refused to raise an army but prepared for battle himself. He ordered a special iron shield to be made, tall and able to withstand the flames, and took up his ancient sword, Naegling. Then he gathered eleven warriors to accompany him to the lair of the dragon. Upon discovering the identity of the thief whod snatched the cup, Beowulf pressed him into service as a guide to the hidden passageway. Once there, he charged his companions to wait and watch. This was to be his battle and his alone. The old hero-king had a foreboding of his death, but he pressed onward, courageous as always, to the dragons lair. Over the years, Beowulf had won many a battle through strength, through skill, and through perseverance. He was still possessed of all these qualities, and yet, victory was to elude him. The iron shield gave way too soon, and Naegling failed to pierce the dragons scales, though the power of the blow he dealt the creature caused it to spew flame in rage and pain. But the unkindest cut of all was the desertion of all but one of his thanes. The Last Loyal Warrior Seeing that Beowulf had failed to overcome the dragon, ten of the warriors who had pledged their loyalty, who had received gifts of weapons and armor, treasure, and land from their king, broke ranks and ran to safety. Only Wiglaf, Beowulfs young kinsman, stood his ground. After chastising his cowardly companions, he ran to his lord, armed with shield and sword, and joined in the desperate battle that would be Beowulfs last. Wiglaf spoke words of honor and encouragement to the king just before the dragon attacked fiercely again, flaming the warriors and charring the younger mans shield until it was useless. Inspired by his kinsman and by thoughts of glory, Beowulf put all his considerable strength behind his next blow; Naegling met the dragons skull, and the blade snapped. The hero had never had much use for edged weapons, his strength so overpowering that he could easily damage them; and this happened now, at the worst possible time. The dragon attacked once more, this time sinking its teeth into Beowulfs neck. The heros body was soaked red with his blood. Now Wiglaf came to his aid, running his sword into the dragons belly, weakening the creature. With one last, great effort, the king drew a knife and drove it deep into the dragons side, dealing it a death blow. The Death of Beowulf Beowulf knew he was dying. He told Wiglaf to go into the dead beasts lair and bring back some of the treasure. The young man returned with heaps of gold and jewels and a brilliant gold banner. The king looked at the riches and told the young man that it was a good thing to have this treasure for the kingdom. He then made Wiglaf his heir, giving him his golden torque, his armor, and helm. The great hero died by the gruesome corpse of the dragon. A huge barrow was built on the headland of the coast, and when the ashes from Beowulfs pyre had cooled, the remains were housed inside it. Mourners bewailed the loss of the great king, whose virtues and deeds were extolled that none might ever forget him.

Advertsing of commodities and cultuer Essay Example | Topics and Well Written Essays - 750 words

Advertsing of commodities and cultuer - Essay Example In advertising for commodities, one should always choose the right marketing strategy. In order for commodities to sell through good advertising, one has to ensure two very important components are checked: price and value. People only respond to commodities that are offered at low prices compared to their competitors. In addition, high value products tend to attract a good market compared to low value commodities (Forker 2012, p.34). Therefore, one has to ensure these two factors are kept at bay when deciding on proper advertising tools. According to Forker (2012), commodities can never sell when they are low value and placed at high prices. It human nature to acquire goods cheaply that he or she fins high quality. Therefore, when one intends to conduct commodity advertising, one has two place these two factors in check, Lowering of prices can only be achieved if the expense of acquiring the commodity is kept low (Forker 2012, p.88). Branding of the commodities is one of the key ways in which one can ensure the commodities sale. Branding basically refers to making the given commodity unique to the consumers (Jackson 2005, p.76). Branding can be achieved through making the commodity highly sort after based on the qualities which it has. One basically needs to be aware of the market which one is targeting. Knowing the target market can be useful in knowing their taste and preference in order to tone down the commodities to the level which satisfies the clients need. In branding, one has to create a unique image that will give your commodity an upper hand over the competitors (Jackson 2005, p.46). In addition, one would have to identify reasons as to why customers purchase commodities from your competitors and try to eliminate them. Commodities that have been branded generally have a good impact of attracting and retaining clients who are attached to it (Jackson 2005, p.88). Brands creates things which people are a ble to associate and relate with. Culture has

Sustainability Essay Example | Topics and Well Written Essays - 1250 words

Sustainability - Essay Example Far beyond the maintenance of systems on earth and humans, sustainability entails also the prevalence of situations and conditions that govern the existence of systems. Generally, sustainability is a measurable entity in terms of biodiversity change due to human globalization and population in addition to the concept of carrying capacity. Social, economic, and environmental dimensions are also studied in the sustainability context due to the role that they play in human life, as well as the existing natural systems. A lot of empirical research has been conducted by researchers and scholars, but no research has exhausted sustainability realms (Liebert 11). 2.0 An overview of sustainability The recent decades have seen rampant entities desire to partake from sustainability, owing to the transformation of natural and artificial systems into volatile entities. 2.1 Definition The period ranging from the 1980 is marked by the relationship of sustainability to the Earth and its sustenance o f humans; however, recent proofs have brought about its relationship with all other natural and artificial systems. This has led to the interlude with the sustainable development in the recent developments, which entails the fulfillment of present requirements alongside eradication of future generation compromise. The history of sustainability dates back to the period when human civilizations started to dominate the ecology, believing that transitions must have a way in the same. Thus, the developing societies have perceived the aspect as that which entails progress in a particular society, mainly marked by the occurrence of conflicts, which some were solved and acted as a rationale for sustainability and others remain unsolved, thus declining sustainability (Ott Konrad 59). 2.2 Enhancement of sustainability Effective Planning is a long-term strategy that would enhance the sustainability of all systems. Vibrant mixed-utilization of high-density national centers and societies develop ment should be duly enabled. Additionally, the mobility realms improvement would act as a rationale to the enhancement of sustainability. Investments directed towards a quality establishment of infrastructure of public transit, which is easily accessible should be emphasized on. In addition, excellent quality bicycle and pedestrian passage should be considerably improved. Phone cell notifications from signage should be utilized in the improvement of mutual connectivity and enhancing rich sources of information. Moreover, the overall economy should be intervened in every state in the world, as a prerequisite to the development of sustainability in addition to unlimited support of businesses both local and international as artificial sustainability systems should be a key step (Ott Konrad 67). 2.3 Rationale for sustainability in distinct realms Sustainability is a major step towards ensuring the efficiency of resources in regard to its integration with options of mobility. Sustainabil ity planning processes impact by creating room for ample choices of transportation, sense of belonging and places and foster public automobiles in place of private entities. Protection of regional

Media Influence on School Children in Britain Essay

Media Influence on School Children in Britain - Essay Example There are both negative and positive implications of media to children in our society today. Media offer academic learning opportunities to school children. Shows such as Teletubbies and Blue’s Clues among others have offered learning opportunities to pre-aged children over the past thirty years. Zoom, Zoboomafoo, and cyber chase programs are sated with edifying scientific facts to the youth. Educational programs have enabled children to highly adapt to the programs they are watching. For instance, Barney show, which teaches the English language, boosts the linguistic ability of those children who don’t understand the English language properly. On the other hand, programs such as National Geographical Channel explores the geographical features enabling a leaner to be conversant with his/her environment. Children are taught different types of animals and they are showing their real appearances. It makes it easier for such kids to visualize.Children have been able to lear n pro-social skills through media. â€Å"Children adapt to social skills like sharing, empathy, and self-calming by watching others do it â€Å", reports Klinker, an author (social and emotional development).Watching of T.V programs such as soap operas helps a child learn from adult hence enhancing the high level of social intelligence.Media has its negative effect on children as well. Children tend to pick up weird unethical behaviors from models presented in on TV screen e.g. eating disorders and body image.... For instance, Barney show, which teaches English language, boosts the linguistic ability of those children who don’t understand the English language properly. On the other hand, programs such as National Geographical Channel explores on the geographical features enabling a leaner to be conversant with his/her environment. Children are taught different types of animals and they are showed their real appearances (Palmer & Young, 2007, p.34). It makes it easier for such kids to visualize when discussed during class sessions. Children have been able to learn pro-social skills through media. â€Å"Children adapt to social skills like sharing, empathy and self-calming by watching others do it â€Å", reports Klinker, an author (social and emotional development).Watching of T.V programs such as soap operas helps a child learn from adult hence enhancing high level of social intelligence (Bryant & Zillmann, 2005 p.45). Media has its negative effect on children as well. Children tend pick up weird unethical behaviors from models presented in on TV screen e.g. eating disorders and body image (Liebert & Sprafkin, 1998 p.29). Magazines tend to portray girls who are skinny. As a result young girl put themselves on diet and at times they restrict themselves to eating in quest for a skinny sexy body. School girls caught up these trends as little as 7 years of age. In 2006, a national eating disorder treatment center indicated that 67% of school teachers complained of eating disorders in their classroom. The issues of modes of dressing and fashion trends have been major issues in the media where by individuals want to be kept updated. Children on the other hand have been on the receiving end. Parents have found it difficult to

International Law Assignment Essay Example | Topics and Well Written Essays - 2500 words

International Law Assignment - Essay Example The region had always been witness to ethnic battles, and the twentieth century saw the most bloody episodes in the unfolding saga of the Balkans. Countries such as the U. S., U. K. and a majority of the European Union are in favour of the declaration and have formally recognized Kosovo as a state. To these countries, Kosovo is officially known as the Republic of Kosovo. The topic of this essay is to determine the legality or otherwise of Kosovo’s declaration of independence. The essay will also deal with the issue of recognition of Kosovo as a state according to the relevant theories. Lastly, it will also examine whether the declaration of Kosovo as a state is proper according to the Montevideo Convention. Kosovo was a part of the nation of Serbia, which succeeded Yugoslavia after its dissolution. It is a Balkan region given to ethnic strife since antiquity. To the Serbs, it is an integral part of Serbia, as the area covers the Kosovo Polje (Blackbird Field). This place is ‘sacred territory for the Serbs as the place where Serbs were ‘defeated and subjugated by the Turks’.1 is where The Kosovo problem is one step in the still to be completed Balkan saga. The area now comprising Kosovo was first defined as an area of a state in 1945 as the autonomous Kosovo-Metohian Area.As a part of Yugoslavia, Kosovo gained limited internal autonomy ihn the later part of the sixties. In the 1974 Constitution of Yugoslavia, Socialist Autonomous Province of Kosovo was given more powers. A President and prime Minister were formally recognised for the Area. It was also represented in the Federal Presidency. It was thus that Kosovo became a republic in the Federation. The Parliament of the un-recognized Republic of Kosovo approved a resolution supporting the "Independence and Sovereignty of Kosovo" in September 1991.   Put to a clandestinely organized and held referendum in Bosnia the resolution was approved overwhelmingly.2 The Dayton Peace Agreement had

Spanglish Term Paper Example | Topics and Well Written Essays - 750 words

Spanglish - Term Paper Example This aspect of Spanglish is also properly discussed in the paper. Spanglish and its History Spanglish is one of the most common languages among the Hispanic Americans. It is nothing but a mixture of English and Spanish. According to Oxford English Dictionary, Spanglish can be described as â€Å"a type of Spanish contaminated by English words and forms of expression, spoken in Latin America† (Lipski, John M. â€Å"Is â€Å"Spanglish† the third language of the South?: truth and fantasy about U. S. Spanish†). The word ‘Spanglish’ was first used by Salvador Tio who was a Puerto Rican journalist. In 1952, Tio used this term in a newspaper article. Quite expectedly many consider him as the creator of this word. Some of the articles that were written by Tio in early days contained few Spanglish words which are humorous in nature. However, most of those words were not used later. As a result initially there was some confusion regarding legitimate examples of Spanglish. Apart from Tio there are experts like Nash and Fairclough who tried to gain insight into this language (Lipski, John M. â€Å"Is â€Å"Spanglish† the third language of the South?: truth and fantasy about U. S. Spanish†). At present, Spanglish is considered as one of common languages especially in the places like Los Angeles where a major section of the population is ‘Hispanic’. ... Some of the Spanglish sentences are found to be Spanish dominated whereas some are mostly English in nature. Over the last two decades, use of Spanglish has increased significantly with the increase in the number of people who are migrated from Latin American countries to United States. English has collided with Spanish on a regular basis in workplaces, retail stores and classrooms (Castro, Janice. & Cook, Dan. â€Å"Language: Spanglish Spoken Here†). Such collisions between two of the most respected languages in the world has developed the growth track of Spanglish. The unique language is found to be very popular among the young people in United States. According to, Ilan Stavans who is an expert of Latino culture, Spanglish is a â€Å"jazzy and a very creative way of being Latino in the U.S. today† (Thomas, Jeffrey. â€Å"Spanglish Offers Stepping-Stone to English†). Stavans is a self-declared promoter and admirer of Spanglish who has defined the language as â €Å"the verbal encounter between Hispano and Anglo civilizations† (Lipski, John M. â€Å"Is â€Å"Spanglish† the third language of the South?: truth and fantasy about U. S. Spanish†). Spanglish and Media Globalization In America people who speak in Spanglish are those who have enough knowledge of Spanish but follow American culture. They use clipped and shorter phrases rather than using longer and graceful expressions. Such style is found to be very much suitable in America where ‘time is money’ (Castro, Janice. & Cook, Dan. â€Å"Language: Spanglish Spoken Here†). Most importantly Spanglish speaking people in US are likely to have the spending power of almost 200 billion dollar. As a result, many companies are eager to make the best out of this huge market. It is found that

International Law Assignment Essay Example | Topics and Well Written Essays - 2500 words

International Law Assignment - Essay Example The region had always been witness to ethnic battles, and the twentieth century saw the most bloody episodes in the unfolding saga of the Balkans. Countries such as the U. S., U. K. and a majority of the European Union are in favour of the declaration and have formally recognized Kosovo as a state. To these countries, Kosovo is officially known as the Republic of Kosovo. The topic of this essay is to determine the legality or otherwise of Kosovo’s declaration of independence. The essay will also deal with the issue of recognition of Kosovo as a state according to the relevant theories. Lastly, it will also examine whether the declaration of Kosovo as a state is proper according to the Montevideo Convention. Kosovo was a part of the nation of Serbia, which succeeded Yugoslavia after its dissolution. It is a Balkan region given to ethnic strife since antiquity. To the Serbs, it is an integral part of Serbia, as the area covers the Kosovo Polje (Blackbird Field). This place is ‘sacred territory for the Serbs as the place where Serbs were ‘defeated and subjugated by the Turks’.1 is where The Kosovo problem is one step in the still to be completed Balkan saga. The area now comprising Kosovo was first defined as an area of a state in 1945 as the autonomous Kosovo-Metohian Area.As a part of Yugoslavia, Kosovo gained limited internal autonomy ihn the later part of the sixties. In the 1974 Constitution of Yugoslavia, Socialist Autonomous Province of Kosovo was given more powers. A President and prime Minister were formally recognised for the Area. It was also represented in the Federal Presidency. It was thus that Kosovo became a republic in the Federation. The Parliament of the un-recognized Republic of Kosovo approved a resolution supporting the "Independence and Sovereignty of Kosovo" in September 1991.   Put to a clandestinely organized and held referendum in Bosnia the resolution was approved overwhelmingly.2 The Dayton Peace Agreement had

Healthy School Lunches for all Children Essay Example | Topics and Well Written Essays - 750 words

Healthy School Lunches for all Children - Essay Example The main activities this campaign involves itself in is advising and educating the government, school administration, parents, food service workers, and the overall public on the benefits of healthy food choices for children for their short-term and long-term health benefits. Most schools serve children food that is high in cholesterol and low in fibre. However, the Healthy School Lunch Campaign encourages more schools to serve children food high in fibre, cholesterol free, and with low fat. The campaign includes presentations in schools, advertisements in the media, posters, among others. This will help reduce the rising obesity rates in America, especially child obesity. The Healthy School Lunches campaign in one of their posters, reaches out to the public by portraying a beautiful young girl thinking, â€Å"President Obama’s daughters get healthy school lunches. Why don’t I?† In this poster, the healthy school lunches organization wants to bring the public the message that healthy eating is important for children. If the daughters of the president do not eat unhealthily, then why should the citizens let unhealthy food to be served to their children? This message creates emphasis to the audience, as it portrays their children as less special, for their continued eating of unhealthy food, compared to Obama’s Sasha and Malia, to whom healthy eating is a priority. The creators of this poster have used different techniques and have skilfully developed a convincing message for the public about healthy eating for children in schools (â€Å"Healthy School Lunches Organization†). The use of an image in this poster is meant to attract people’s attention to reading the poster. In this case, the image is that of a young girl. She is a beautiful, smiling, and innocent-looking young girl, of around 10 years of age. This girl is shown thinking about how the presidents’ daughters eat healthily while she does not eat in the sa me healthy manner at school. When people see such an image, it draws them into thinking about the addressed issue of unhealthy eating. They will feel sorry for the young girl, considering it is not her mistake to be served unhealthy lunc

Drug Card Essay Example for Free

Drug Card Essay Vicodin - Indication: Relief of moderate to severe pain - Safe Range: Peds: lt;40kg 0. 2mg/kg-15mg/kg/dose q3-4h PRN. Maximum dose of acetaminophen 1000 mg/dose and 4000mg/day; Adult initially 10mg q3-4h PRN. - Action / Where does it do its job: Reduces intensity of pain stimuli incoming from sensory nerve endings, altering pain perception. Contraindications: None known. Previous hypersensitivity - Side Effects: Sedation, HOTN, diaphoresis, dizziness, facial flushing. Children lt;2 y. o. more susceptible to RESPIRATORY DEPRESSION. - Strengths: (Vicodin) hydrocodone/acteminophen 5/500 mg ; Vicodin ES h/a 7. 5/750 mg; Vicodin HP h/a 10/650mg and 10/660mg ; - - Drug Name: Hydrocodone/Acetaminophen Trade Name:  Norco - Indication: Relief of moderate to severe pain - Safe Range: Peds: lt;40kg 0. 2mg/kg-15mg/kg/dose q3-4h PRN. Maximum dose of acetaminophen 1000 mg/dose and 4000mg/day; Adult initially 10mg q3-4h PRN. - Action / Where does it do its job: Reduces intensity of pain stimuli incoming from sensory nerve endings, altering pain perception. Contraindications: None known ; Previous hypersensitivity - Side Effects: Sedation, HOTN, diaphoresis, dizziness, facial flushing. Children lt;2 y. o. more susceptible to RESPIRATORY DEPRESSION. - Strength: hydrocodone/acetaminophen 10mg/325 mg; 5mg//325mg, 7. 5mg/325mg - Drug Name: Acetaminophen/Codeine Trade Name: Tylenol with codeine - Indication: Mild to moderate pain, fever - Safe Range: 0. 5-1. 0mg/kg/dose q3-6h. [3-6 yo] Dose: 12 mg codeine PO q4-6h prn; [7-12 yo]Dose: 15-30 mg codeine PO q4-6h prn; [13-17 yo]Dose: 15-60 mg codeine PO q4-6h prn; Max: 60 mg/dose, 360 mg/day codeine; 1 g/4h and 4 g/day acetaminophen; Alt: 0. 5-1 mg/kg codeine PO q4-6h prn; - Action / Where does it do its job:  Ã‚  Inhibits the synthesis of prostaglandins that may serve as mediators of pain and fever, primarily in the CNS. Contraindications: Previous hypersensitivity. Active alcoholism, hepatic disease, severe renal impairment, phenylketonuria, G6PD deficiency. - Side Effects: hypersensitivity reaction, hepatotoxicity, hepatic failure, renal failure. - Strength: Codeine with acetaminophen 30/300mg ; 60/300mg; Tylenol with codeine solution ( codeine 12mg/acet. 120mg/5ml)

Role Of Metal Ions In Biochemistr

Role Of Metal Ions In Biochemistr A metal is a chemical element that is a good conductor of both electricity and heat and forms cations and ionic bonds with non-metals. In chemistry, ametal (from Greek ÃŽÂ ¼ÃƒÅ½Ã‚ ­Ãƒ Ã¢â‚¬Å¾ÃƒÅ½Ã‚ ±ÃƒÅ½Ã‚ »ÃƒÅ½Ã‚ »ÃƒÅ½Ã‚ ¿ÃƒÅ½Ã‚ ½ mà ©tallon, mine]) is an element, compound, or alloy characterized by high electrical conductivity. In a metal, atoms readily lose electrons to form positive ions (cations). Those ions are surrounded by delocalized electrons, which are responsible for the conductivity. The solid thus produced is held by electrostatic interactions between the ions and the electron cloud, which are called metallic bonds.[2] Metal ions play essential roles in about one third ofenzymes . These ions can modify electron flow I a substrate or enzyme, thus effectively controlling an enzyme-catalyzed reaction. They can serve to bind and orient substrate with respect to functional groups in the active site, and they can provide a site for redox activity if the metal has several valence states. Without the appropriate metal ion, a biochemical reaction catalyzed by a particular metalloenzyme would proceed very slowly, if at all. The enzyme provides an arrangement of sidechain functional groups having an appropriate sized hole with the preferred groups on enzyme side chains needed to bind the required metal ion. The optimal number of such binding groups is chosen for the particular metal ion, together with the appropriate hydrophobic or hydrophilic environment in the binding site. Metal ions may be bound by main-chain amino and carbonyl groups, but specific binding is achieved by the amino acid side chains, particularly the carboxylate groups of aspartic and glutamic acid, and the ring nitrogen atom of histidine. Other side chains that bind metals ions include tryptophan (ring nitrogen), cysteine (thiol), methionine (thioether), serine, threonine, tyrosine (hydroxyl groups), and asparagine and glutamine (carbonyl groups, less often amino group . No set of general rules exists that describes how a given metal ion will behave in an enzyme . Now that many crystal structures of proteins are being studied by X-ray diffraction, information on the binding of metal ions in the active sites of enzymes is available and should provide clues to the mechanism of action of the enzyme.The examples of catechol methyltransferase andmandelate racemase will be discussed later in this article.The work described here includes results fromexaminations of the crystal structures in the CambridgeStructural Database and the Protein Databank . Astudy of binding, however, also involves an analysis ofthe energetic consequences of changing the way thebinding occurs, so that the most stable binding pattern fora given group of ligands can be deduced. We haveapproached this using ab initio molecular orbital and density functional calculations . In this way weobtain both the binding geometry of ligands and theenergetic consequences of changing this binding m ode. Properties of metal ions Metal ions are generally positively charged and act as electrophiles, seeking the possibility of sharing electron pairs with other atoms so that a bond or charge-charge interaction can be formed. They behave rather like hydrogen ions (the poor mans metal). Metal ions, however, often have positive charges greater than one,and have a larger ionic volume so that they can accommodate many ligands around them at the same time. In addition, metal ion concentrations can be high atneutral pH values, while hydrogen ion concentrations are, by the definition of pH, low at these values. Ligands are the atoms or groups of atoms that are bonded to the metal ion, generally in an electrostatic manner. They are usually neutral or negatively charged and they donate electron density to the metal ion. Thecoordination number of a metal ion, that is, the number of ligand atoms bound to it, is viewed in terms of concentric spheres; the inner sphere containing those atoms in contact with the metal ion, the second sphere containing those in contact with the inner sphere ligand atoms. The number of atoms in these spheres will depend on the size of the metal ion and the sizes of the ligand atoms. For example, sodium is smaller than potassium, and sulfur is larger than oxygen. Measurements of metal ion-liganddistances in crystal structures led to the idea of atomic and ionic radii [9-11]; anion radii can also be derived from the minimum anion-anion distances in crystal structures. The radius ratio, a concept introduced by Goldschmidt [11], is the ratio of the radius of the cation to that of the anion and is generally less than 1.0 Tetrahedral structures have a radius ratio between 0.225 and 0.414, while octahedral structures have a ratio between 0.414 and 0.645. For example, the radius of Mg2+ is 0.65 D, while that of O2- is 1.40 D and their radius ratio is 0.464; the packing is octahedral. The charge distribution in the active site of an enzyme is designed to stabilize the transition state of the catalyzed reaction relative to that of the substrate. In enzyme-catalyzed reactions it is essential that the reactants be brought together with the correct spatial orientation, otherwise the chance of the reaction taking place is diminished and the reaction rate will be too low.The electrostatic environment in the active site is a major factor that serves to guide the substrate to the binding site in the correct orientation. Metal ions can assist in this process, often binding groups in a stereochemically rigid manner, thereby helping to control the action of the enzyme. Thus, an enzyme will bind its substrate in such a manner that immobilization and alignment, ready formation of the transition state of the reaction to be catalyzed,and then easy release of the product will result; metal ions often help in accomplishing this process. Each metal ion has its own chemistry. An example of the differing reactivities of metal cations is provided by their ability to bind or lose water molecules. The exchange of coordinated water with bulk solvent by various cations has been categorized into four groups: those for which the exchange rate is greater than 108 per second including alkali and alkaline earth metal ions(except beryllium and magnesium), together with Cr3+,Cu2+, Cd2+, and Hg2+. Intermediate rate constants (from 104 to 108 per second) are found for Mg2+ and some of the divalent first-row transition metal ions. Those with slow rate constants (from 1 to 104 per second) include Be2+ and certain trivalent first-row transition metal ions. The inert group with rates from 10-6 to 10-2 per second containsCr3+, Co3+, Rh3+, Ir3+, and Pt2+. One of the factors involved in rates of exchange is the charge-to-radius Ratio; if this ratio is high the exchange rate is low.An important reaction catalyzed by metal ions inenzymes is the ionization of water to give a hydrated hydrogen ion and a hydroxyl anion. Initial studies of this process will be discussed here as they are relevant to the action of a metal ion in providing a hydroxyl group and a hydrogen ion for use in an enzymatic reaction. Polarizing Potential of Various Ions Atoms or groups of atoms are considered polarizable if, when they are placed in an electric field, a charge separation occurs and a dipole is acquired. This deformability or polarizability is measured by the ratio of the induced dipole to the applied field. Those atoms that hold on less firmly to their electrons are termed more polarizable. It is found that if two ions have the same inert gas structure (potassium and chloride, for example), the negatively charged anion is more polarizable than the positively charged cation, which holds on to its electrons more tightly. The word hard has been introduced to indicate a low polarizability so that the electron cloud is difficult to deform (like a hard sphere). By contrast soft means high polarizability so that the electron cloud is readily deformed . A hard acid or metal cation holds tightly to its electrons and therefore its electron cloud is not readily distorted; its unshared valence electrons are not easily excited. Soft (polarizable) metal cations contain electrons that are not so tightly held and therefore are easily distorted or removed. A hard acid prefers tocombine with a hard base, while a soft acid prefers to bind with a soft base by partially forming covalent bonds .The type of binding is related to the highest occupied molecular orbital (HOMO) of the electron-pair donor (a lewis base, the ligand) and the lowest unoccupied molecular orbital (LUMO) of the electron-pair acceptor (a Lewis acid, the metal ion). If these have similar energies, then electron transfer will give a covalent (soft) interaction, whereas the energy difference is large, electron transfer does not readily take place and the interaction is mainly electrostatic (hard-hard). Hardcations include the alkali and alkaline earth metal ions while soft metal ions include Cu 2+, Hg2 2+, Hg2+, Pd2+. Inbiological systems, hard ligands generally contain oxygen while soft ligands contain sulfur. Hard acids tend to bind hard bases by ionic forces, while soft acids bind soft bases by partially forming covalent bonds. These hard-soft categorizations are a help in understanding the relative binding preferences of various cations. Most metal ions of biological significance are hard or intermediate between hard and soft. Most soft metal ions and soft ligands are poisonous and they interact with other soft species in the body. For Pb2+ the harder ligands are found in hemidirected structures and the softer ligands in holodirected complexes.Nature has devised many enzyme systems in which a metal ion interacts with the oxygen of a water molecule.If a water molecule can be dissociated into a hydrogen ion and a hydroxyl group, the latter can serve as a nucleophile in chemical a nd biochemical reactions.Nature has chosen activation of a water molecule as a means to obtain such a nucleophile in situation so that a chemical reaction can occur in a stereochemically controlled manner in the active site of the enzyme. The questions we ask are as follows: 1) how does nature ensure that the specific water molecule will be activated; 2) how does nature compensate for the lower water activation power of some cations over others (since a wide variety of metal ions may not be available in the particular active site and the enzyme has to do the best it can with what is available); and 3) how does nature ensure that the required reaction occurs. Ab initio molecular orbital and density functional calculations have been carried out to measure the extent to which a series of metal cations can, on binding with water, cause it to be dissociated into its component hydrogen ions (subsequently hydrated in solution) and hydroxyl ions. Initial data indicate that the charge of the metal ion plays a significant role in modifying the pKa of water. The binding enthalpies of a wide variety of metal ion monohydrates, M[H2O]2+ , have been published [21] but their deprotonation enthalpies are still under investigation. Geometry of Metal-Ion Binding to Functional Groups The geometries of metal ion-carboxylate interactions have been studied in order to determine the following: 1)which lone pair of an oxygen atom in a carboxylate group, syn or anti, is preferred for metal cation binding; 2) does the metal ion lie in the plane of the carboxylgroup; and 3) under what conditions do metal ions share both oxygen atoms of the carboxylate group equally? We found that cations generally lie in the plane of the carboxylate group . The exceptions to this mainly include the alkali metal cations and some alkaline earth cations; these metals ionize readily and form strong bases so it is not surprising that they have less specific binding modes. When the distance of the metal cation to the carboxylate oxygen atoms is on the order of 2.3-2.6 D, the metal ion tends to share both oxygen atoms equally. Otherwise one oxygen atom of the carboxylate group is bound to the metal ion and the other is not. Calcium ions often form bidentate interactions, while it is less common for the smaller magnesium ions. Imidazole groups in histidyl side chains of proteins bind metal ions in a variety of enzymes. One imidazole can, by virtue of its two nitrogen atoms, bind one or two metal ions, depending on its ionization state and the suitabilities of the metal ion. The bases in DNA can also bind metal ions. We have analyzed hydrogen bonding to and from nitrogen atoms in nitrogen-containing heterocycles for crystal structures in the Cambridge Structural Database. It was found that for hydrogen bonding, a slight out-of-plane deviation of the binding atom often occurs. Metal ions bind more rigidly in the plane of the imidazole group. The energetic cost of such deviations were analyzed by ab initio molecular orbital calculations. In an investigation of protein crystal structures in the Protein Databank it was found that the binding of metal ions to histidine in proteins is more rigid and the location of the metal ion is more directional. Thus, if an enzyme needs to control the location and orientation of a carboxylate or imidazole group, it can accomplish this better with a metal ion than by hydrogen bonding. Metal ions in proteins are often involved in structural motifs. When a metalloenzyme carries out its catalytic function it uses one of a few possible three-dimensional arrangements of functional groups around the metal ion to ensure the specificity of the required biochemical reaction. Thus, if such catalytic metal-binding motifs can be identified and categorized, then incipient reactivities of enzymes could be inferred from their three-dimensional structures. Such a categorization, however, requires an understanding of the underlying chemistry of any metal ion in the active site. One motif identified in the crystal structure of cobalt(II) formate consists of a carboxyl group in which one oxygen atom is bound to the metal ion and the other is bound to metal-bound water, to give a cyclic structure. This motif has been found in many metalloenzyme crystal structure , such as D-xylose isomerase . The roles of these motifs are of interest. The metal ion-hydrated-carboxylate motif (I) is planar and commonly found. It does not, however, affect the ability of the metal ion (in studies of Mg2+ complexes) to ionize water. On the other hand, for magnesium ions (which generally have a rigid octahedral arrangement of binding groups) it utilizes 2 of the 6 coordination positions and therefore serves to orient the arrangement of ligands, an effect we have labeled coordination clamping. Motif (II) is also found in several crystal structures such as that of the -subunit of integrin CR3 . It appears to help bind subunits together. A third motif (III) is found in D-xylose isomerase and involves two metal ions with several carboxylate ligands and a histidine ligand . The metal site that binds only oxygen atoms can bind substrate in place of the two water molecules and orient the substrate. The second metal ion site (with histidine as one ligand) then positions a metal ion-bound water molecule to attack the substrate. Roles of Metal Ions in Enzyme Action The crystal structure of mandelate racemase with bound p-iodomandelate provides a useful example of the importance of a metal ion in a reaction . The enzyme binds a magnesium ion by means of three carboxyl groups. The substrate mandelate has displaced water from the magnesium coordination sphere and binds by means of its carboxylate group and an a-hydroxy group.The magnesium ion will lie in the plane of the carboxyl group, as shown by our studies of metal ion-carboxylate interactions . The magnesium holds the substrate firmly in place so that the catalytic abstraction and addition of a hydrogen atom by His 297 or Lys 166 is precisely effected . The magnesium probably also aids this activity by affecting the electronic flow in the carboxylate and hydroxyl groups by mild polarization. We have found that metal ion coordination is better than a hydrogen bond in aligning a functional group; there is considerable flexibility in a hydrogen bond as we found for imidazoles . In the reaction c atalyzed by the enzyme mandelate racemase the magnesium ion binds substrate . A Histidine (His 297) and Lysine (Lys 168) are positioned to abstract a hydrogen ion from the substrate and, if it is added again from the other side, racemization occurs. Hydrogen bonding to a carboxylate group of the substrate helps to stabilize an enolate intermediate in the reaction. In catechol O-methyltransferase , a methyl group is transferred from the sulfur of Sadenosy[ methionine to catechol. The magnesium ion is oriented by a motif of type I and it binds substrate in such an orientation that a hydroxyl group is near the S-CH3 group, and the other hydroxyl group is held in place by a carboxylate group. There are many other examples of two-metal ion active sites, such as hemerythrin, alkaline phosphatase and superoxide dismutases (which have been well documented). These studies of the geometries and energetics of metal-ion ligand b inding can therefore aid in our understanding of metalloenzyme function Metals in the RNA worid By combining our limited knowledge of metal-ion-binding to contemporary RNAs and our more extensive knowledge of metal-ion-binding to proteins, it is possible to speculate on the role of metal ions in prebiotic molecular evolution. It seems clear that specifically bound metal ions coevolved with RNA molecules. Many of the mononuclear sites in Table 5 are formed with, or can be engineered into, small RNA fragments. Since such sites are highly hydrated and contain limited direct contact with the RNA, the observed affinities are only moderate, in the 1-1000 ÃŽÂ ¼M range. These sites are also expected to show limited specificity, predominantly dictated by the chemical nature of the ligands. Furthermore, in these examples, the RNA structures themselves are likely to be quite flexible and can accommodate a variety of metal ions with only minor distortions to the overall RNA fold. These minimalist sites are sufficient to stabilize the secondary and tertiary structures observed in these motifs. The metal ion sites generated on small RNAs appear to be capable of facilitating a variety of different types of chemistry. Activities range from the transesterification and hydrolytic reactions of small ribozymes (Pyle 1996; Sigurdsson et al. 1998) to the more exotic porphyrin metalation (Conn et al. 1996) and Diels-Alder condensation reactions (Tarasow et al. 1997) catalyzed by aptamers produced from in vitro selection experiments.These small RNAs have only limited amounts of structure and therefore are likely to position the catalytic metal ions by only a few points of contact. The relatively modest rate enhancements supported by catalytic RNAs such as these probably reflect the types of species that first evolved from random polymerization events. Very active metal ions might have assisted in this process but would have increased the danger of side reactions that would accidentally damage the catalyst. A striking difference between most RNA metal-binding sites studied thus far and those seen in proteins is the degree of hydration. Both structural and catalytic metal-ion-binding sites in proteins are predominantly dehydrated (Lippard and Berg 1995). Water molecules occasionally appear in the coordination spheres of these metal ions, but in these cases, they are often believed either to be displaced by the substrate when it enters the active site or to take part in the catalytic mechanism of the enzyme. Such protein sites also bind their metal ions much more tightly than the RNA systems. In fact, tight binding is a requirement for dehydrated sites, since there is a characteristic energy (ÄHhyd) associated with the hydration of any ion. The net binding energy upon coordination of the ion must account for the energetic cost of dehydration. The question arises, Why are such dehydrated sites not observed in RNAs? One possibility is that metal-binding sites in RNAs are intrinsically different from those in proteins. RNA has a much more limited set of ligands to use in generating a specific metal-binding pocket. Amino acid side chains containing thiols and thioethers are well suited to binding a variety of softer metals. In addition, the carboxylate side chains provide anionic ligands with great versatility in their potential modes of coordination. They can act as either terminal or bridging ligands and bind in either monodentate or bidentate geometries. The nucleotides, on the other hand, are much larger and more rigid than the corresponding amino acids. The anionic ligand in RNA, the nonbridging phosphate oxygen, is an integral component of the backbone and therefore is more limited in its conformational freedom than the aspartate and glutamate carboxylate groups. The heterocyclic ring nitrogens and the keto oxygens from the bases are held in rigidly planar orientations by the aromatic rings. This geometric constraint severely limits the ability of an RNA to compact encompass a metal ion and provide more than facial coordination and therefore complete dehydration. It also explains why the most specific metal-binding sites are not in the Watson-Crick base-paired regions of the structure where the conformation is too constrained. Instead, metalion- binding sites are clustered in regions of extensive distortion from the A-form RNA helices. There is also the question of the folding of RNAs relative to that of proteins. It is possible that in RNAs there is insufficient energy in the folding and metal-binding process to completely displace the waters of hydration around a metal ion. It has been suggested that in contemporary RNAs, modified nucleotides might be present to assist in metal ion binding (Agris 1996). A more straightforward possibility, however, is that most RNAs studied to date are structurally too simple. In these RNAs, most residues involved in metal ion binding are solvent-exposed. Thus, the RNAs have no real inside comparable to the hydrophobic core of a protein. The largest RNA crystallographically characterized to date is the P4-P6 domain. On the basis of that structure, it was proposed that an ionic core may substitute in RNA folding for the hydrophobic core of proteins such that the 3 ° structure assembles around a fixed number of discrete metal-binding sites (Cate et al. 1997). Even in this structur e, however, the most buried of the metal-binding sites are significantly hydrated. It could be that all metal-ion-binding sites in RNA are at least partially hydrated. One can imagine several advantages to using hydrated ions within the ionic core of a large RNA. Hydrated ions would span larger voids than dehydrated ions and allow looser packing of secondary structure elements. The hydrated ion also can accommodate a wide range of structural interactions through its orientation of the water molecules as compared to direct coordination of metal ions at every site. In addition, the energy associated with deforming the outer-sphere interactions should be significantly less than what would be observed for distorting the innersphere coordination. A consequence of RNAs having a core of hydrated ions is that one might expect this core to be much more dynamic than the hydrophobic core of a protein. In the modern protein world, metal cofactors are associated with a variety of reaction types, including electron transfer, redox chemistry, and hydrolysis reactions. Trans esterification and hydrolytic activities, however, are the primary catalytic behaviors observed in ribozymes. Did these other catalytic activities not develop until the dawn of the protein world, or are there undiscovered natural catalytic RNAs that are the ancestors of the early redox enzymes? Through the use of in vitro selection experiments, the scope of RNA catalysis has been significantly broadened is almost certainly capable of catalyzing these other classes of reactions, but it is still unclear whether there are naturally occurring examples. Such an enzyme would likely use a metal ion cofactor other than Mg(II), so the search for RNA molecules that naturally use alternative ions is of significant interest. A recent selection experiment showed that a single base change results in an altered metal ion specific ity for RNase P (Frank and Pace 1997). It is clear from this result that catalytic RNAs retain the ability to adapt to an everchanging environment, using the resources available to evolve and to overcome evolutionary pressures. Were RNAs to have evolved out of an environment devoid of metal ions, they probably would have found a way around the problems of folding and generating reactive functional groups. The primordial soup and all cellular environments that have evolved subsequently contained a variety of ions, however. Given the availability of metal ions, they will certainly play a significant role in the biology of current and future RNAs. Effect of metal ions on the kinetics of tyrosine oxidation by Tyrosinase The conversion of tyrosine into dopa [3-(3,4-dihydroxyphenyl)alanine] is the rate limiting step in the biosynthesis of melanins catalysed by tyrosinase. This hydroxylation reaction is characterized by a lag period, the extent of which depends on various parameters, notably the presence of a suitable hydrogen donor such as dopa or tetrahydropterin. We have now found that catalytic amounts of Fe2+ ions have the same effect as dopa in stimulating the tyrosine hydroxylase activity of the enzyme. Kinetic experiments showed that the shortening of the induction time depends on the concentration of the added metal and the nature of the buffer system used and is not suppressed by superoxide dismutase, catalase, formate or mannitol. Notably, Fe3+ ions showed only a small delaying effect on tyrosinase activity. Among the other metals which were tested, Zn2+, Co2+, Cd2+ and Ni2+ had no detectable influence, whereas Cu2+ and Mn2+ exhibited a marked inhibitory effect on the kinetics of tyrosine ox idation. These findings are discussed in the light of the commonly accepted mechanism of action of tyrosinase. Tyrosinase (monophenol,dihydroxyphenylalanine oxygen oxidoreductase; is a copper-containing enzyme responsible for melanogenesis in plants and animals, which catalyses both hydroxylation of tyrosine to dopa and its subsequent oxidation to dopaquinone (Hearing et al., 1980; Lerch, 1981). The first reaction, which represents the rate-limiting step in melanin biosynthesis (Lerner et al., 1949), is characterized by a lag period that has subsequently been explained in terms of a hysteretic process of the enzyme (Garcia Carmona et al., 1980). The extent of this induction time depends on various parameters including, besides pH and both substrate and enzyme concentration, the presence of a suitable hydrogen donor. Kinetic studies carried out on tyrosinases from various sources (Pomerantz, 1966; Pomerantz Murthy, 1974; Hearing Ekel, 1976; Prota et al Abbreviations used: dopa, 3-(3,4-dihydroxyphenyl)-alanine; SOD, superoxide dismutase. To whom correspondence and reprint requests should be addressed. 1981) have shown that dopa, in very low concentration, is the most effective reducing agent in eliminating the lag period, whereas other catechols, such as dopamine, adrenaline and noradrenaline, behave similarly to ascorbate and NADH and NADPH in only shortening it, even at high concentration. Tetrahydropterin, a well-known specific cofactor of other aromatic hydroxylases (Lerner et al., 1977; Marota Shiman, 1984), is also effective in stimulating tyrosinase activity, although to a lesser extent than dopa. At present, no other organic or inorganic substances have been reported to shorten or lengthen the lag period of tyrosine oxidation. Although metal ions are known to play a role in many biologi cal processes, little attention has been directed to their possible involvement in melanogenesis, particularly in the early enzymic stages .As a part of our continuing studies on the chemistry of melanin pigmentation (Prota, 1980; Sealey et al., 1982; Palumbo et al., 1983), we report the results of a survey on the effect of metal ions on the activity of purified Sepia tyrosinase, readily available in large amounts from the ink of the cephalopod Sepia officinalis thermostability of amalyse Three Metal Ions Participate in the Reaction Catalyzed by T5 Flap Endonuclease*à ¢- ¡ Protein nucleases and RNA enzymes depend on divalent metal ions to catalyze the rapid hydrolysis of phosphate diester linkages of nucleic acids during DNA replication, DNA repair, RNA processing, and RNA degradation. These enzymes are widely proposed to catalyze phosphate diester hydrolysis using a two-metal-ion mechanism. Yet, analyses of flap endonuclease (FEN) family members, which occur in all domains of life and act in DNA replication and repair, exemplify controversies regarding the classical two-metal-ion mechanism for phosphate diester hydrolysis. Whereas substrate-free structures of FENs identify two active site metal ions, their typical separation of>4 AËÅ ¡ appears incompatible with this mechanism. To clarify the roles played by FEN metal ions, we report here a detailed evaluation of the magnesium ion response of T5FEN. Kinetic investigations reveal that overall the T5FEN-catalyzed reaction requires at least three magnesium ions, implying that an additional metal ion is bound. The presence of at least two ions bound with differing affinity is required to catalyze phosphate diester hydrolysis. Analysis of the inhibition of reactions by calcium ions is consistent with a requirement for two viable cofactors (Mg2_ or Mn2_). The apparent substrate association constant is maximized by binding two magnesium ions. This may reflect a metal dependent unpairing of duplex substrate required to position the scissile phosphate in contact with metal ion(s). The combined results suggest that T5FEN primarily uses a two-metal-ion mechanism for chemical catalysis, but that its overall metallobiochemistry is more complex and requires three ions. Key cellular processes such as DNA replication, DNA repair, RNA processing, and RNA degradation require the rapid hydrolysis of the phosphate diester linkages of nucleic acids. The uncatalyzed hydrolysis of phosphate diesters under biological conditions is an extremely slow process with an estimated half-life of 30 million years at 25  °C (1). Protein nucleases and RNA enzymes produce rate enhancements of 1015-1017 to allow this reaction to proceed on a biologically useful time scale. Most enzymes catalyzing phosphate diester bond hydrolysis have a requirement for divalent metal ions. Based largely upon crystallographic observations, most metallonucleases are proposed to catalyze reactions using a two-metal-ion mechanism (Fig. 1a) analogous to that suggested for the phosphate monoesterase alkaline phosphatase (2, 3), although this view is not universally accepted. Three recent reviews present contrasting views on the roles of metal ions in protein nuclease and RNA enzyme reactions and illustrate this controversy (4-6). One family of metallonucleases over which there has been considerable mechanistic debate are the flap endonucleases (FENs)3 (7-12), which are present in all domains of life and play a key role in DNA replication and repair. Unlike most metallonucleases, which typically possess a cluster of three or four active site carboxylates, the FEN active site is constructed from seven or eight acidic residues located in similar positions in FENs from a range of organisms (Fig. 1b, see also supplemental Fig. S1) (7, 9, 10, 13-16). Several FEN x-ray structures also contain two active site carboxylate-liganded divalent metal ions, designated as metals 1 and 2 (9, 13-15). The position of metal 1 is similar in all cases, but the metal 2 location varies. In all but on

Multi Track History :: essays research papers

60s Research Document 4.1.1,2 History and development of the Multitrack Recorder Multitrack recorders were originally developed in the early 1950s in Germany. The initial principle of multitracks was to divide a tape in two parts and record different sounds onto each and play them back concurrently. The fact that both tracks would be on the same tape would mean they would be synchronised exactly. In classical music recordings of the 1950s, the early two track machines were first used and recorded in stereo. Two different mics would be used and these signals would be recorded simultaneously. Pop and jazz recordings however, remained in mono until the mid sixties. The first three track recorder is attributed to Les Paul who developed the system with his wife, singer Mary Ford. Ampex were soon to realise the possibilities of such a machine and bought the device from Paul. Ampex quickly released a refined version of the three track which was in common use until the birth of 4-track in the mid 1960s. Many Motown hits and, maybe most famously, Phil Spector’s â⠂¬ËœWall Of Sound’ were recorded on three track machines. When 4-track was born, a new world of recording and bouncing possibilities was opened up to the recording industry. Most Beatles and Rolling Stones albums were recorded in 4-track and Abbey Road became world renowned in the art of 4-track recording. Their engineers seemed to be able to create vast recordings, which required numerous bounces, whilst keeping unwanted bounce noise to a minimum. 4-track also paved the way for innovations in sound such as Quadraphonic. This system used each track as a means of creating a 360 ° mix. Albums like Pink Floyd’s ‘Dark Side Of The Moon’ and Mike Oldfield’s ‘Tubular Bells’ were recorded in Quadraphonic (as well as Stereo) but the system never really took off. It did however have a significant part to play in the development of surround sound. By 1970 the 16-track recorder was emerging in the rock scene of the United States though the Beatles stuck with the 8-track to record their final albums. Split bank designs became popular offering a main bank of faders used for the mic/line inputs, a separate bank controlling monitor levels and cue mixes and a final section used for other submixes and reverb chambers. The typical price for a 16-track recorder was around $35,000 however the problem of noise build up with numerous tracks still existed (this is the main reason for the lack of interest in 24-track machines at the time).