Earned Value Management Essay Example | Topics and Well Written Essays - 750 words

Earned Value Management - Essay Example It compares the work finished with the estimates made at the beginning of the project, which gives a measure of how far the project is from being finished. Inferring from the amount of work already put into the project, a project manager can get reasonable prediction as to how much resources the project will have used at completion. EVM was used in the 1800s as industrial engineers looked for ways to measure performance in factories. The United Stated Department of Defense (DOD), in the 1960s, employed the Cost/Schedule Control System Criteria (C/SCSC) which is now referred to as the Earned Value Management System (EVMS), a recognized function of program management, which ensures that technical, cost, schedule, and aspects of a contract are truly integrated. The DOD used the C/SCSC cost system simply because their contractors ran over budget, lag behind schedule, had no ability to guesstimate an acceptable cause-effect relationship of how cost, schedule or scope impacted multiple and simultaneous projects. As a result, the government requested that contractors were no longer permitted to forecast costs by subtracting project actual costs from the original budget. With the EVMS, which includes organized components of the project's schedule, budget estimate and scope of work, project's forecast costs at completio n of project are more accurately determined (Warhoe, 2004). However, after nearly four decades, EVM clearly has not achieved its actual or perceived potential. Of the innumerable projects, less than 1% use the EVM application. One reason suggested in literature for the low usage of EVM and procurement is the contract type selection bias toward cost-reimbursable (CR) contracts. Literature review addressing EVM and procurement, indicate that there are mixed beliefs on contract type selection (Marshall, 2005). Conventional use of EVM with CR contracts, were limited to large United States government departments such as the National Aeronautics and Space Administration (NASA). Today NASA employs EVM to support President Bush's Management Agenda specifically to improve competitive sourcing by providing better historical performance data; to enhance financial performance by helping measurement of performance against the budget; and to advance NASA budget and performance integration by integrating management of technical requirements, schedule, and budget risks. In contrast, many project practitioners, experts and literature reviews argue in support of using fixed price (FP) contracts. Kelvin Yu described how EVM was effectively used with a FP contract to renovate a wind tunnel operated by NASA. For instance, Yu utilized EVM in defining the project scope, developing negotiating tools such as "should cost estimate", and directing and integrating the actual work of multiple contractors working on a project. Quentin Fleming and Joel Koppleman agree because both have noted the efficiency and effectiveness of EVM with FP contracts. Authors are suggesting the use EVM with FP contracts and provide sound rationale for their beliefs and claims. They made a good case for continuous use of FP (Marshall, 2005). For those such as Karen Evans, an Office of Management and Budget (OMB) Administrator of e-government and Information Technology, who testified last spring before the House Government Reform Committee, EVM has not been of much service. Her complaint

Refer to attachments ( Feature writing) Essay Example | Topics and Well Written Essays - 1000 words

Refer to attachments ( Feature writing) - Essay Example The chain in the US has about 270 branches (sizzler.com). At present there are two braches in Singapore, one at Suntec and the other at Toa Payoh. Sizzler is famous for its mouth watering and sizzling steaks, crunchy seafood and creamy salads and desserts. The opening hours from 1100 to 2200 hours are quiet reasonable so we decided to be there by 0100 hours. When we entered the place I was impressed by the clean, colorful and calm look of the place. It wasn’t much of a romantic place yet I couldn’t help grading it any less. The walls were decorated by a number of attractive paintings together with colorful pictures with prices of food on it; this made it easier for us to order the right kind of food. A genial manger with a smile on his face greeted us and explained how the menu works. I liked the tranquility of the place. The dining hall was very well lit too. The sofa-type chairs fixed near the windows were colorful and seemed comfortable. The view from the windows was exquisite. The menu, with all the details and pictures of the food, on it was quite detailed helpful. There were several steak items, seafood choices, chicken varieties, and burgers listed in the menu. The exclusive Suntec-salad-bar-promotion was enticing because it offered a saving of $3. The multihued menu appeared like a rainbow. The variety of steaks was quite tempting too. The steak variety included: Sizzler steak complimented with Shitake mushroom sauce, Ribeye scallop sauce with premium scallop sauce, Teriyaki Mushroom Cheese Steak basted with Teriyaki glaze topped with mushrooms, Swiss cheese and crispy onion stack, fillet mignon, and trio pepper steak with trio pepper sauce. We, however, ordered Teriyaki mushroom cheese steak. The amazing thing about Sizzler was its separate kids’ menu with a variety of choices including Beery Patty, Chix Little, Chix Nuggets, and Fis Fis Fillet. The two kids decided to go for Fis Fis Fillet (sizzler.com.sg). The

Modifications to the National School Lunch Program Essay Example for Free

Modifications to the National School Lunch Program Essay Introduction Recent modifications made to the National School Lunch Program menu have caused controversy all across the nation. In last year The National School Lunch program have been under scrutiny and major changes have been made to the ingredients and preparation of school lunches. The USDA reports that the all the modifications to the school lunches are focus towards improving the health of all school age children, contributing to the fight against childhood obesity and succinctly to improve the health of all children across the nation. This research would explore the history of the different federal agencies involve in the national nutritional services, the most comprehensive changes in the school nutritional environment , the old and new menus choices and how changes are impacting students (National School Lunch Program,[NSLP] 2012). Research Statement According to the Unites States Department of Agriculture Food and Nutrition Service the recent changes to the National School Lunch program have been an important aid in the fight against childhood obesity and to help change student eating habits towards a healthier approach. In the last 4 years the Senate of the United Stated has proposed different legislature changes to the National School Lunch menu allowing millions of dollars to contribute towards a healthier approach modifying what student age children are consuming during school hours. The most comprehensive changes have been oriented towards reducing fat, sugar and sodium, and including more vegetable as part of the daily school cafeteria menu (United States Department of Agriculture, [USDA] 2012). Initial Research Question How the recent changes to the national school lunch program can improve the student’s health? By analyzing the recent changes to the national school lunch program we will be able to compare some of the differences between some the new and improve school lunch menu and how these changes are impacting students across the nation. Review of literature The National School Lunch Act was a law established under the administration of President Harry Truman in 1946. The original purpose of the act was to help local farmers with surplus produce and using these foods to feed school age children. After reviewing the principles of the act, members of the senate requested the establishment of a national program that under the guidelines of the National School Lunch Act, would oversee all operations associated with school lunch meals, reason for the creation of the National School Lunch program. The National School lunch program manages one of the largest federally assisted meal programs that provides nutritionally balanced meals free or at low cost to school age children. The national school lunch program takes cash subsides and foods provided by the U.S Department of Agriculture, in return the national school lunch program must meet nutritional federal requirements and most important must offer meals free or at low cost to all student age children. According to reported statistics from the U.S Department of Agriculture the National School Lunch feeds over 30 million students each day (NSLP, 2012) There is no doubt that the student nutrition subject has been an important topic of national concern in the history of our country. In 1966, The Child Nutrition Act was a law signed by President Lyndon B Johnson, encouraged by a national concern over nutrition in school age children. The Child Nutrition Act became to be an instrument to facilitate the process of meeting nutritional needs of children under the guidelines of the National School Lunch Program. The act also helped established the school based breakfast program providing free breakfast for children in public and nonprofit schools, during the signing of this act president Johnson use a famous phrase that would change forever the futures of national school lunches â€Å"Good food is essential to good learning† (USDA, 2012) U.S Department of Agriculture is a federal funded division who is responsible to all operations in the nation pertaining to farming agriculture and food. Better known as the USDA the department not only promotes and helps farming and agriculture issues but ensures food safety across the nation. The USDA is one of the oldest federally department created by President Abraham Lincoln in 1862. The USDA oversees a vast amount of operative units in the united states including the USDA Food and Nutritional Services who major goal is to provide healthy food to families in need, the department also collaborate closely with the National School Lunch program providing foods that are of nutritional value (USDA, 2012) On December 13th, 2010 President Obama sign into a law the Healthy, Hunger –Free Act of 2010. This act was creating to combat the alarming rates of childhood obesity cases in the U.S. The now law came to update the school meals standards who reflected very little changes in nutrition in the last 15 years, the HHFK Act also had an impact on the USDA, changing the foods providing to the National School lunch program and succinctly reflecting changes in meal nutritional standards in schools across the nation. In the 2009 a review from the Institute of Medicine recommended several updates to the National School lunch menus, the review found that the school cafeteria menus were not meeting the dietary guidelines for school age children stated by the U.S Department of Agriculture Food and Nutrition Services (Healthy Hunger-Free Act, [HHFA] 2012) In 2011 the USDA proposed new regulations based on the finding of the Institute of Medicine of the United States. The process of modification of the school cafeteria menus begin slowly but steady on schools across the nation, the changes included whole grain servings on all meals; reduce saturated fat sugar and sodium, and more fresh fruit and vegetables. Elizabeth Ippel, executive director of The Academy of Global Citizenship in Chicago, talks about the important of nutrition’s â€Å"good nutrition is essential and a very integral component to effective learning†. The changes are significant and according to Mrs. Ippel the students are responding positive to the modifications (Leamy, 2012) Here’s an example of a before and after lunch menu: BeforeAfter Breaded beef patty on a white roll Baked Fish Nuggets Fruit popsicleWhole wheat roll Low fat milkMashed potatoes Broccoli Peaches Skim Milk Discussion On December 13, 2010 president Obama signed into law 111-296 the Healthy Hunger –Free Act of 2010. The act is one of the most comprehensive proposals in the school nutritional environment in over 15 years; the main goal of this law is to update school meals nutritional standards to help combat childhood obesity and help students achieve healthy eating habits. Beginning in July 2012 the new lunch meal pattern will be in effect changing what students will be consuming during lunch in the school year 2012-2013.The new proposed meal components includes key changes for children K and above, these changes requires that school lunches offer a daily variety of whole grains, fruit and vegetables. In the fruit category, each meal provided by school cafeterias must include  ½ cup of fresh, frozen or canned fruits, prepared or compound with water and not syrup.  ½ of vegetables on each meal is another requirement in the daily school lunch menus; the new regulations required a variety of vegetable groups including: dark green, red/orange, legumes, starchy and other vegetables. On the area of whole grains, breads and cereals are required on each meal as long as the food item includes more than 8 grams of grains. The act has also limit the amount of flavored milks opting for only low fat milk during meals. Calories are also under a scope view limiting the calorie ranges according to age groups. Trans-fat is banned completely from school cafeteria menus and the act has also a plan to limit sodium gradually over the next decade, to reach the goal of keeping sodium at a no more than 600 mg per meal, equal to a diet frozen meal (HHFKA, 2012). The changes in the cafeteria school menu are impacting students and teachers equally, besides of more nutritional value, the new menus now offered more quantity amounts of healthier foods, satisfying the hunger of millions of students and reflecting healthier attitudes in the classrooms. LuAnn Coenen from Appleton Central High School in Wisconsin cheers the new regulations in the cafeteria menus and states† Since the introductions of the new food program, I have noticed and enormous difference in the behavior of my students in the classroom,†Ã¢â‚¬ I can say without hesitation that it’s changed my job as principal†. It seems that less sugary foods and drinks are impacting student’s behavior. An associate professor of education at the Lehigh university conducted a study of over 2000 lunchrooms across the nations, the conclusions indicated that healthier and less sugary meals carries a calmer atmosphere in the classroom this calmer demeanor is reflects when students go back to the classrooms creating a trickling effect. Taylor a student from Appleton High commented about the changes she felt since the cafeteria menus changed â€Å"I’d say being able to concentrate better†. Susan Graham principal from Melrose Elementary in Tampa Florida confirms that her discipline referrals have decreased 50 % â€Å"We get a lot more done, I think it’s a lot more efficient work environment for all of us,† Grahams said (abcnews,2012). Berger (2005) wrote about the importance of a well balanced meal for the proper development of children’s brain development, and how school meal programs played an important rolled in children’s brain development, by providing a well balanced meal while in school children can achieve proper brain development a subsequently their ability to learn will be maximized (Berger, 2005). The changes happening in schools cafeterias might seem insignificant, but replacing extra-cheese pizza, deep fried chicken for whole wheat pizza and baked fish nuggets, represent a huge step towards making students healthy. Some modifications to the school lunch menu have happened slowly and some hidden from students, like replacing full fat cheese with a low fat mozzarella cheese in the pizzas, as well as using whole wheat bread on grill cheese sandwiches. Dr. Saira Jan a Rutgers University Professor (2006) comments on children obesity and diabetes rising numbers â€Å"Kids choose from what they are offered. They are hungry, they will eat. You can offer carrots or French fries. We have a big health-care problem. We can’t just talk about it† (Weekly Reader, 2006). Conclusion In conclusion the overall national concern over childhood obesity and the rising rate of diseases in children related to overweight issues is currently being addressed by different entities in charge of school nutrition. The National School lunch program has and will make modification on the students’ lunch menu to feed students healthier foods in the effort to fight childhood obesity. Even though there has been mixed opinions about the effectiveness of the lunch menu modifications, the HHFKA guidelines demonstrate how References About USDA. (2012). United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.usda.gov/wps/portal/usda/usdahome?navid=ABOUT_USDA Berger, Kathleen. (2005).The Developing Person Throughout the Lifespan. 6th ed.Worth. 140-142 Child Nutritional Act.(2012). United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.gpo.gov/fdsys/pkg/FR-2012-01-26/pdf/2012-1010.pdf Food Fight! Should School Lunches be healthier? Current Events, a Weekly Reader publication,17 Feb.(2006) Retrieved from Healthy Hunger-Free Kids Act of 2010. (2012).United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.fns.usda.gov/cnd/governance/legislation/cnr_2010.htm Questions Answers on the Final Rule, â€Å"Nutrition Standards in the National School Lunch and School Breakfast Programs†(2012).United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.fns.usda.gov/cnd/Governance/Policy-Memos/2012/SP10-2012osr2.pdf Lazor, K., Chapman, N., Levine, E. (2010).No.80. Vol.4. 200-206 Soy Goes to School: Acceptance of Healthful, Vegetarian Options in Maryland Middle School Lunches. Journal Of School Health. Leamy, Elizabeth.(2011). Exclusive: USDA to Announce Healthier New School Lunch Guidelines. Retrieved from http://abcnews.go.com/Health/ConsumerNews/usda-announce-school-lunch-guidelines/story?id=12603193 Mary Bruce. (2010). Coming Soon? Healthier School Lunches. Retrieved from http://abcnews.go.com/Politics/healthier-school-lunches-senate-approves-45-billion-bill/story?id=11345256 Mcginn, D., Popescu, R. (2007).No 150. Vol.17. Unlucky Charms At Lunch. Newsweek. Retrieved from http://mediacast.usw.edu:8045/ps/i.do?id=GALE%7CA169875850v=2.1u=nm _a_elinit=rp=ITOFsw=w National School Lunch Program.(2012).United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.fns.usda.gov/cnd/Lunch/ Nutrition Standards in the National School Lunch and School Breakfast Programs, No 17, Vol.77. (2012). United States Department of Agriculture Food and Nutrition Service. Retrieved from http://www.gpo.gov/fdsys/pkg/FR-2012-01-26/pdf/2012-1010.pdf Students behave better with healthy lunches. (2012). Abc. go. Retrieved from http://abcnews.go.com/GMA/AmericanFamily/story?id=125404page=1

Biomedical instrumentation and measurement

Biomedical instrumentation and measurement INTRODUCTION: SA node controls the rate of hearts muscular contractions which enables the heart to circulate the blood throughout the body according to the need. Small variations in the heart beat are not harmful but in some cases due to malfunctioning of the hearts electrical system, the heart rate varies drastically resulting in different types of arrhythmias. These cardiac arrhythmias are serious disorders which should be treated immediately. Arrhythmias like bradycardia (low heart rate) can be treated using Pacemakers. Pacemakers can be implanted in the patients heart for permanently stimulating the heart. It is used for patients for whom the SA node is no longer functioning properly. External Pacemakers are also available which is used to treat temporary heart rate variations. It is used for a short period of time before the implanting the Internal Pacemakers in the heart. In order to understand the requirement of pacemakers, it is necessary to understand the functioning of the heart and its electrical system. HEART ITS ELECTRICAL SYSTEM: Heart is a pumping device which is used to circulate the blood throughout the body. It has four chambers namely Right Atrium, Left Atrium, Right Ventricle and Left Ventricle. The right atrium receives the deoxygenated blood from the entire body through the superior vena cava and inferior vena cava. The left atrium receives oxygenated blood from the lungs through the pulmonary veins. When the atrium contracts the blood flows to the corresponding ventricle. This is due to atrial depolarization. When the left ventricle contracts, the oxygenated blood is supplied to all tissues in the body through the aorta. This is due to ventricular depolarization. Similarly, the deoxygenated blood is pumped to the lungs for oxygenation through the pulmonary artery during the contraction of right ventricle. This is due to ventricular repolarization. The Electrical conduction system of the heart consists of SA node, AV node, Bundle of His, Purkinje Fibers. The chambers of the heart should be stimulated electrically for contraction. The stimulations are provided by the SA node (Natural Pacemaker of the heart) which is located in the right atrium of the heart near the entrance of the superior vena cava. Although all the heart cells have the ability to produce electrical pulses which can stimulate the heart, SA node triggers the heart. The fact that SA node produces pulses at a higher rate when compared to other potential cells which can stimulate contraction, contributes to this phenomena. The contraction of various chambers of the heart is characterized in a very specific manner. As the electric pulses pass through each chamber of the heart, they are stimulated to contract. The SA node first triggers the right and left atrium to contract. Then the impulses travel to the AV node which is located between the atria and the ventricles . From AV node ,the pulses travel to the bundle of his. The pulses travel to the individual ventricles through the right and left bundle branch and reach the Purkinje fibers. If the SA node fails, then the AV node acts as the primary pacemaker. If the AV node fails, then the Purkinje fibers takes the responsibility. The SA node receives blood supply from right and left coronary arteries. Under ischaemic conditions, the death of the affected cells will stop the SA node from triggering the heart beat. There is a period of time following the stimulation of heart muscle during which no other action potential can trigger the heart muscles. This period is known as Absolute or Effective Refractory Period (ERP) of heart. It is normally around 0.4 sec. ERP is maintained as high as possible in order to maintain tachycardia and to coordinate the muscle contraction. The anti-arrhythmic drugs taken by the patients usually prolongs the ERP. ELECTRICAL SYSTEM OF HEART ECG ITS SIGNIFICANCE: The electrical activity of the heart muscles is recorded as Electrocardiogram (ECG). It can be acquired non-invasively from the surface of the body by following specific lead configurations. The electrical current generated in the heart due to depolarization and repolarization is spread not only within the heart but also throughout the body. So, ECG can be easily acquired from the surface of the body through electrodes. ECG has four basic components namely, P wave, QRS complex, T wave and U wave. P wave occurs during atrial contraction due to atrial depolarization. The duration of the P wave ranges from 0.08- 0.1 sec. During the atrial depolarization, the impulse from the SA node spreads throughout the atrium. The time period between the onset of the P wave and the beginning of the QRS complex is about 0.12- 0.2 sec. During the zero potential period between the P wave and QRS complex, the impulse travels within the AV node and the Bundle of His.QRS complex occurs during ventricular c ontraction due to ventricular depolarization. The duration of the QRS complex ranges from 0.06-0.1 sec. T wave occurs during ventricular relaxation due to ventricular repolarization. Sometimes, a small positive U wave occurs following the T wave due to the last remnants of the ventricular repolarization. ELECTROCARDIOGAM NORMAL AND ABNORMAL ECG WAVES: Normal ECG: NORMAL ECG Heart rateis nothing but the number ofheartbeatsper unit oftimewhich is expressed as beats per minute (bpm) which can vary as the bodys need for oxygen changes, such as duringexercise or sleep. The measurement of heart rate is used bymedical professionalsto assist in thediagnosisand tracking of medical conditions. It is also used by individuals, such asathletes, who are interested in monitoring their heart rate to gain maximum efficiency from their training. TheR waveto R wave interval(RR interval) is the inverse of the heart rate ,that is one divided by RR interval gives the heart rate. Typical healthy resting heart rate in adults is 60-80 bpm which is referred to be normal heart rate,with rates below 60 bpm referred to asbradycardia and rates above 100 bpm referred to astachycardia. Missed ECG: MISSED ECG This can be detected when the R-R interval is twice the actual R-R interval (for normal subjects).Heart pulses misses at some intervals and does not follow the premature heart beat. Bradychardia: BRADYCARDIA This is a critical reduction of heart rate and characterized by normally directed abnormally wide P waves and normal PR interval. Whenever the R-R interval exceeds 1 sec the heart rate goes below 60 and the condition is referred to as Bradychardia. There are three types of Bradychardia conditions based on the characteristics of the ECG wave, they are Sinus bradychardia, Atrio-ventricular nodal bradychardia and ventricular bradychardia respectively. They are discussed below. Sinus bradycardia: SINUS BRADYCARDIA Sinus bradycardias are also called as Atrial bradychardias. This bradychardia condition is usually found in young and healthy adults. The symptoms represent with the individualsrespirations. Theabnormalpattern of eachinhalationcorresponds with the heart rate decreasing.Expirationcauses an increase in the hearts rate of contraction. This is thought to be caused by changes in the vagal tone duringrespiration. Sinus bradycardia is a sinus rhythm of less than 60 bpm. It is a common condition found in both healthy individuals and those who are considered wellconditioned athletes. The reason for this is that their heart muscle has become conditioned to have a higher stroke volume and therefore requires fewer contractions to circulate the same volume of blood. Sick sinus syndromecovers conditions that include severe sinus bradycardia, sinoatrial block, sinus arrest, and bradycardi-tachycardia syndrome (atrial fibrillation, flutter, and paroxysmal supraventricular tachycardia). Atrio ventricular nodal bradycardia: ATRIO VENTRICULAR NODAL BRADYCARDIA An atrio ventricular nodal bradycardia or AV junction rhythm is usually caused by the absence of the electrical impulse from thesinus node. This usually appear on anEKGwith a normal QRS complexaccompanied with an inverted P wave either before, during, or after the QRS complex. An AV junctional escape is a delayed heartbeat originating from anectopicfocus somewhere in theAV junction. It occurs when the rate ofdepolarizationof the SA node falls below the rate of the AV node.This dysrhythmia also may occur when the electrical impulses from the SA node fail to reach the AV node because of SA or AV block.This is a protective mechanism for the heart, to compensate for a SA node that is no longer handling the pace making activity, and is one of a series of backup sites that can take over pacemaker function when the SA node fails to do so. This would present with a longerPR interval. A junctional escape complex is a normal response that may result from excessive vagal tone on the SA node. Pathological causes include sinus bradycardia, sinus arrest, sinus exit block, or AV block. Ventricular bradycardia: VENTRICULAR BRADYCARDIA This picture shows an ECG of a person with an abnormal rhythm (arrhythmia) called an atrioventricular (AV) block. P waves show that the top of the heart received electrical activity. Each P wave is usually followed by the tall (QRS) waves. QRS waves reflect the electrical activity that causes the heart to contract. When a P wave is present and not followed by a QRS wave (and heart contraction), there is an atrioventricular block, and a very slow pulse (bradycardia). PACEMAKER AND ITS SIGNIFICANCE: More than 60% people fall victim to heart attacks in most of the countries around the globe every year and thousands more are critically injured in accidents. Taking care of these patients in special care units involves the usage of specialized equipments like pacemakers along the other important ones. In the past few years electronic pacemaker systems have become the important one in saving lives of cardiac patients whose normal pacing functions have been impaired. Depending on the exact nature of a cardiac dysfunction, a patient may require temporary artificial pacing during the course of treatment or permanent pacing in order to lead an active, productive life after treatment. A device capable of generating artificial pacing impulses and delivering them to the heart is known as a pacemaker system (commonly called a pacemaker) and consists of a pulse generator and appropriate electrodes. Pacemakers are available in a variety of forms. They are mainly divided into two types External pacemakers and Internal pacemakers respectively. EXTERNAL PACEMAKER: External pacemakers are used on the patients with temporary heart irregularities, such as those encountered in the coronary patient, including heart blocks. They are also used for temporary management of certain arrhythmias that occur in the patients during critical postoperative periods and in the patients during cardiac surgery, especially if the surgery involves the values or septum. An external pacemaker usually consists of an externally worn pulse generator connected to electrodes located on or within the myocardium. External pacemakers, which include all types of pulse generators located outside the body, are normally connected through wires introduced into the right ventricle via a catheter catheter. The pulse generator may be strapped to the lower arm of a patient who is confined to bed, or worn at the midsection of an ambulatory patient. We have made the pacemaker which can be divided into two general categories namely Asynchronous pacemaker Synchronous pacemaker ASYNCHRONOUS PACEMAKER: This type of pacemaker is intended for patients having permanent heart blocks. The rate is preset. It can be varied externally within the range of 60 PPM to 180 PPM. Since this pacemaker functions regardless of the patients natural heart rhythm it poses a potential danger because of competition between the patients rhythm and that of the pacemaker. PACING PULSES FROM ASYNCHRONOUS PACEMAKER SYNCHRONOUS PACEMAKER: In patients who have normal heart function most of the time, asynchronous pacing can be extremely dangerous, working against their own physiological pacemaker with the danger of stimulating in the vulnerable period of the T wave, a condition that can result in fibrillation. The demand pacemaker consists of an ECG amplifier and a conventional pacemaker output pulse circuit that has been modified to allow output from the ECG amplifier to inhibit the pulse generator. This pacemaker senses R-waves and its timing and logic circuits count out an elapsed time interval following an R-wave or previously induced pulse. If the intrinsic R-wave does not appear before the elapsed time interval, the ventricle is stimulated. If an R-wave is received, the counter is reset again. This type of pacemaker is used for patients with bradycardia, and it ensures a heartbeat no slower than its set rate. PACING PULSES FROM SYNCHRONOUS PACEMAKER INTERNAL PACEMAKER: Internal pacemaker are implanted within the pulse generator placed in a surgically formed pocket below the right or left clavicle, in the left subcostal area, or in women, beneath the left or right major pectoralis muscle. Internal leads connect to electrodes that directly contact the inside of the right ventricle or the surface of the myocardium. The exact location of the pulse generator depends primarily on the type of the electrode used, he nature of the cardiac dysfunction, and the method (mode) of pacing that may be prescribed .Since there are no external connections for applying power, the pulse generator must be completely self contained, with a power source capable of continuously operating the unit for a period of years. BIO POTENTIAL ELECTRODES: A wide variety of electrodes can be used to measure bio electric events but nearly all can be classified as belonging to one of three basic types; Micro electrodes Skin surface electrodes Needle electrodes All three types of bio potential electrodes have the metal-electrolyte interface. In each case, an electrode potential is developed across the interface, proportional to the exchange of ions to the metal and the electrolytes of the body. MICROELECTRODES: They are used to measure bio electric potentials near or within a single cell.Microelectrodes are electrodes with tips sufficiently small to penetrate a single cell in order to obtain readings from within the cell. The tip must be small enough to permit penetration without damaging the cell. This action is usually complicated by the difficulty of accurately positioning an electrode with respect to a cell. Because of their small surface area, they have impedances well up into the megohms. For this reason, amplifiers with extremely high impedances are required to avoid loading the circuit and to minimize the effects of small changes in interface impedance. SKIN SURFACE ELECTRODES: Skin surface electrodes are used to obtain bio electric potentials from the surface of the body. They are available in various size. Although any type of surface electrode can be used to sense ECG, EMG, EEG potentials, the larger electrodes are usually associated with ECG, since localization of the measurement is not important. Smaller electrodes are used in EEG and EMG measurements. Various types of disposable electrodes have been introduced in recent years to eliminate the requirement for cleaning and care after each use. In general, disposable electrodes are of the floating type with simple snap connectors by which the leads, which are reusable, are attached. Although, some disposable electrodes can be reused several times, their cost is usually low enough that cleaning for reuse is not warranted. They come pre gelled, ready for immediate use. NEEDLE ELECTRODES: To reduce interface impedance and, consequently, movement artifacts, some electroencephalographers use small subdermal needles to penetrate the scalp for EEG measurements. They are also used to measure EMG potentials from a specific group of muscles. They are less susceptible to movement artifacts when compared with surface electrodes as they create an interface beneath the surface of the skin. By making direct contact with the subdermal tissue or the intercellular fluids, these electrodes also seem to have lower impedances than surface electrodes of comparable interface area. Even though needle electrodes have less motion artifacts ,surface electrodes are used to acquire ECG because surface electrodes are more convenient for the patient .Most of the surface electrodes are cheap and reusable. ACQUISITION OF ECG USING 3 LEAD SYSTEM LEAD I CONFIGURATION: ECG sensors measure the time-varying magnitude of electric fields emanating from the heart. ECG values are measured by placing non-invasive electrodes at the surface of the patients skin. For a 3-lead ECG sensor, the electrodes need to be placed in a triangle (Einthoven Triangle) on the patients chest as shown in the figure 11. Each corner of the triangle corresponds to one of the limbs: right hand, left hand, left foot. With the bipolar system, one limb is connected to the positive terminal of the amplifier and another limb to its negative terminal. Three limbs (right arm-RA, left arm-LA and left leg/foot-LL) are used. The right leg was used as earth, to minimize interference. ECG AMPLIFIER: Bioelectric signals have very high input impedance. To stop the signal attenuation, we use Instrumentation Amplifier (AD 624) which also has high input impedance. It should have high gain and low output impedance .In order to remove the common mode signals ,it should have a high Common Mode Rejection Ratio (CMRR of about 90 dB).The potential at the surface of the body ranges from 0 10 mV so the amplifier should have high gain (1000). We use a differential amplifier to amplify the bioelectric signals that occur as a potential difference between two electrodes, the bioelectric signals are applied between the inverting and non-inverting inputs of the amplifier. The signal is therefore amplified by the differential gain of the amplifier. For the interference signal, however, both inputs appear as though they were connected together to a common input source. Thus, the common mode interference signal is amplified only by the much smaller common mode gain. The electrode impedances form a v oltage divider with the input impedance of the differential amplifier. If the electrode impedances are not identical, the interference signals at the inverting and non-inverting inputs of the differential amplifier may be different, and the desired degree of cancellation does not take place. Because, the electrode impedances can never be made exactly equal, the high common mode rejection ratio of a differential amplifier can only be realized if the amplifier has an input impedance much higher than the impedance of the electrodes to which it is connected. There are different lead configurations such as 3-Lead, 5-Lead, 12-Lead for acquiring ECG Signal. We have used 3-Lead system Lead I Configuration. 12-CIRCUIT FOR ECG AMPLIFIER AMPLIFIER OUTPUT SOFTWARE IMPLEMENTATION USING LABVIEW: LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for Visual Programming Language from National Instruments. LabVIEW is a graphical programming environment used by millions of engineers and scientists to develop sophisticated measurement, test, and control systems using intuitive graphical icons and wires that resemble a flowchart. LabVIEW offers unrivaled integration with thousands of hardware devices and provides hundreds of built-in libraries for advanced analysis and data visualization. The LabVIEW platform is scalable across multiple targets and operating systems. LABVIEW is a GUI (Graphical User Interface) which can be used for processing of signals, images and other forms of data. One of the most powerful features LabVIEW offers engineers and scientists is its graphical programming environment. With LabVIEW, one can design custom virtual instruments by creating a graphical user interface on the computer screen through which one can: Operate the instrumentation program Control selected hardware Analyze acquired data Display results One can customize front panels with knobs, buttons, dials, and graphs to emulate control panels of traditional instruments, create custom test panels, or visually represent the control and operation of processes. The similarity between standard flow charts and graphical programs shortens the learning curve associated with traditional, text-based languages. The behavior of the virtual instruments can be determined by connecting icons together to create block diagrams, which are natural design notations for scientists and engineers. With graphical programming, one can develop systems more rapidly than with conventional programming languages, while retaining the power and flexibility needed to create a variety of applications. We have used Lab view to acquire the signal, filtering and do other processing of the ECG signal. The real time signal is given into as input to ELVIS I which acts as the DAQ (data acquisition system).The block diagram of the Lab view implementation is as shown in figure 14. STEPS INVOLVED IN LABVIEW IMPLEMENTATION: The ECG signal from the amplifier (using AD 624) is given as input to DAQ for acquiring the signal in Lab view software. FFT of the ECG signal is obtained and viewed. We can see the frequency content of the ECG signal from the FFT obtained. WE can also see the presence of 50 Hz power line interference in the FFT of raw ECG. A Smoothing filter with following specifications Moving average, Rectangular filter with a half width of 20 is constructed. The Smoothened ECG is viewed. Smoothing Filter is used to remove noise and 50 Hz power line interference. The Smoothened signal is given as input to the Butterworth Band Pass Filter of order 2 and a low cutoff frequency of 5Hz and high cut off frequency of 15Hz.Band Pass Filter is used to separate the QRS complex from the ECG Signal. The output of the Band Pass Filter is differentiated and squared inorder to enhance the QRS complex from the remaining portion of the waveform. The heart rate is calculated using timing and tone measurement block. The block gives the frequency of repetition of the QRS complex. The frequency value is converted into time value by taking inverse of it. Heart rate is calculated as follows. Heart Rate = 60/R-R Interval Example: R-R Interval = 760ms Heart Rate = 60/760ms = 78.94 Beats /Minute If the calculated heart rate is below the normal value, then pacing pulses are produced .This is done by using a case structure. The case structure turns on only when the case is true (Heart Rate is below normal value).Inside the case structure we have a square wave generator. The output of the square wave generator is differentiated and squared. We get a pulse as a result of these operations. The rate and amplitude at which the pulses are produced can be modified easily at run time using controls. Whenever the heart rate is normal, False condition is selected . For false condition, we set the amplitude and frequency of the square wave as zero so that the pacemaker is switched off. The Pacing Pulses generated can also be taken out as an analog voltage from the ELVIS and can be viewed in a DSO. Only voltages in the range +10 volts to -10 volts can be taken out from LABVIEW through ELVIS. PACEMAKER FINAL BLOCK DIAGARM. FRONT PANEL IN LABVIEW ENTIRE SOFTWARE IMPLEMENTATTION We have implemented the case structure and other blocks by studying the general tutorials given in LV BASICS 1 MANUAL and LABVIEWBASICSII_85_ENG CLAD. HARDWARE IMPLEMENTATION: BLOCK DIAGRAM FOR HARDWARE IMPLEMENTATTION BAND PASS FILTER: The amplifier which is used in software implementation (AD 624) is also used here. It is followed by a filter. The amplifier output is around 550 mV. A Filter is a circuit that is defined to pass a specified band of frequencies while attenuating all signals outside this band. Filter networks may be either active or passive. Passive filter networks contain only resistors, inductors and capacitors. Active filters employ transistors or op amps plus resistors, inductors and capacitors. Inductors are often used in active filters, because they are bulky and costly and may have large internal resistive components. Band Pass Filters pass only a band of frequencies while attenuating all frequencies outside the band. A simple high pass filter followed by a low pass filter will form a band pass filter. We have used a band pass filter (0.5Hz 40 Hz) to remove high frequency signals like EMG and low frequency components like Base Line Wandering and motion artifacts. We have used a second order Bu tterworth Filter with -40 db/decade roll-off. For Low Pass Filter, we used 0.5 Hz as the cut off frequency.C1 is chosen as a convenient value between 100 pF and 0.1Â µF.For High Pass Filter, we used 40 Hz as the cut off frequency. We have implemented a Band Pass Filter according to the design given in OPERATIONAL AMPLIFIERS AND LINEAR INTEGRATIONAL CIRCUITS. CIRCUIT AND DESIGN FOR BAND PASS FILTER NOTCH FILTER: A Notch Filter transmits frequencies in the pass band and rejects undesired frequencies in the stop band. In applications where low level signals must be amplified, there may be present one or more of an assortment of unwanted noise signals. Examples are 50, 60 0r 400 Hz frequencies from power lines, 120 Hz ripple from full wave rectifiers, or even higher frequencies from regulated switching type power supplies or clock oscillators. If both signals and signal frequency noise component are passed through a notch filter, only the desired signals will exit from the filter. The noise frequency is notched out. We have designed a active notch filter (using LM 324) to remove 50 Hz Power Line Interference. The amplitude of the acquired ECG signal is around 1 2 V. We got noise free ECG for real time signal acquisition as shown below. CIRCUITAND DESIGN FOR NOTCH FILTER REAL TIME ECG ACQUISITION QRS DETECTOR: In order to extract the QRS Complex from the ECG signal obtained, we use a band pass filter with center frequency of 17 Hz and band width of 6 Hz. The QRS signal obtained from the band pass filter is rectified for comparing with the threshold voltage generated by the detection circuit. The filtered and rectified ECG is stored on a capacitor. This filtered and rectified ECG is compared with the fraction of this voltage. Whenever a threshold voltage is exceeded, the QRS pulse is detected. After the detection of every QRS pulse, the capacitor recharges to a new threshold value after every pulse. CIRCUIT FOR QRS DETECTION MONOSTABLE MULTIVIBRATOR: Monostable Multivibrator generates a single output pulse in response to an input signal. It is also known as One Shot Multivibrator. The time period of the output pulse depends only on the external components (resistors and capacitors) connected to the op-amp. The duration of the input triggering pulse can be longer or shorter than the expected pulse. The duration of the output pulse is represented by the T. Since T can be changed only by changing the resistors and capacitors ,the one shot multivibrators can be considered as a pulse stretcher. This is because the width of the pulse can be longer than the input pulse. In a stable or standby state, the output of the multivibrator is zero or low-level logic. The output of the multivibrator is forced to go high (ËÅ"Vcc) when an external trigger is given. The output stays zero until the next triggering pulse is given. Then the cycle repeats. The monostable multivibrator has only one stable state. Hence, the name monostable. The QRS detector gives a pulse for QRS detected which is given as an input trigger for a monostable multivibrator. This monostable multivibrator is used to produce a positive pulse (amplitude 5V) of desired pulse width for every input triggering (negative edge triggering) from the QRS detector. We had used 555 Timer as a monostable multivibrator. MULTIVIBRATOR OUTPUT Thus, the analog section of the project gets over with multivibrator. The output of the multivibrator is processed using PIC18F 4550 Microcontroller. It marks the beginning of the controller section. MICROCONTROLLER: PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instruments Microelectronics Division. The name PIC initially referred to Programmable Interface Controller, but shortly thereafter was renamed Programmable Intelligent Computer. PICs are popular with developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming (and re-programming with flash memory) capability. Like all Microchip PIC18 devices, PIC18F4550 family are available as both standard and low-voltage devices. Standard devices with Enhanced Flash memory, designated with an F in the part number (such as PIC18F4550),accommodate an operating VDD range of 4.2V to 5.5V.Low-voltage parts, designated by LF (such as PIC18LF4550), function over an extended VDD range of 2.0V to 5.5V. Our project uses a standard PIC 18F4550.Hence this microcontroller uses a flash program memory of 24K bytes .It is a 8-bit microcontroller and so they handle data as 8-bit chunks. PICs have a set of registers that function as general purpose ram. Special purpose control registers for on-chip hardware resources are also mapped into the data space. The addressability of memory varies depending on device series and in PIC 18F4550 external code memory is directly addressable which is an exceptional feature compared to baseline and mid line core devices. PICs have a hardware call stack, which is used to save return addresses. The hardware stack is not software accessible on earlier devices, but this changed with the 18F4550 device. Hardware support for a general purpose parameter stack was lacking in early series, but this greatly improved in the 18F4550, making the this device architecture more friendly to high level language compilers. Core features All of the devices in thePIC18F 455 series family incorporate a range of features that can significantly reduce power consumption during operation. Key items include: Alternate Run Modes: By clocking the controller from the Timer1 source or the internal oscillator block, power consumption during code execution can be reduced by as much as 90%. Multiple Idle Modes: The controller can also run with its CPU core disabled but the peripherals still active. In these states, power consumption can be reduced even further, to as little as 4% of normal operation requirements. On-the-Fly Mode Switching: The power managed modes are invoked by user code during o

Trifles Essay -- essays research papers fc

Little Trifles Add Up to a Big Case Detectives are always looking for little pieces of evidence when investigating a crime. After all, it is this evidence that can turn a trial around, whether be it for the good or bad. This is especially the case in Susan Glaspell's Trifles. When Mrs. Hale comes across little pieces of evidence, she passes them off as being "trifles", hiding them from the detective. She is the sole reason that very little evidence is collected that would convict Mrs. Wright, and can be believed to have some sort of involvement in the murder of John Wright. Mrs. Hale, being estranged from Mrs. Wright for over a year, had something to prove when she went into the house that day. Whether it is out of guilt from not seeing Mrs. Wright, or because she was actually an accomplice in helping Mrs. Wright get away with the act, we'll never know. However, Mrs. Hale knew what she was doing when she started to dismiss evidence before the detective's eyes had seen it. She was also very committed to showing that Mrs. Wright wasn't a bad homemaker, dismissing most of that evidence also. Mrs. Hale first shows signs of her guilt when she defends some bad housekeeping evidence, blaming it on things that men do. When attention it brought to a dirty towel, Mrs. Hale dismisses it because " Men's hands aren't always as clean as they might be"(1121). Her actions are then...

Keyborading And Info Processing Pg 57 58 :: essays research papers

1.  Ã‚  Ã‚  Ã‚  Ã‚  Mindy left her coat here. Can she stop by for it? 2.  Ã‚  Ã‚  Ã‚  Ã‚  Do you plan to go today? The game begins at four. 3.  Ã‚  Ã‚  Ã‚  Ã‚  I wrote to Mr. Katz, but Miss Dixon sent the form 4.  Ã‚  Ã‚  Ã‚  Ã‚  Do you know if Luic and lex Bauner are with br. Tu? 5.  Ã‚  Ã‚  Ã‚  Ã‚  The Beau Monde Singers will perform at Music Hall. 6.  Ã‚  Ã‚  Ã‚  Ã‚  Lennox corp. now owns the Hyde Park athletic club. 7.  Ã‚  Ã‚  Ã‚  Ã‚  Did you ask if the OEA contest is to be on Friday? 8.  Ã‚  Ã‚  Ã‚  Ã‚  Dos FBLA meet on Wednesday, Thursday, and Friday. 9.  Ã‚  Ã‚  Ã‚  Ã‚  August was very hot, but September is rather cool. 10.they are to spend July and august at Myrtle Beach. Page 58 1.  Ã‚  Ã‚  Ã‚  Ã‚  Script is copy that is written with pen on paper 2.  Ã‚  Ã‚  Ã‚  Ã‚  Copy that is written poorly is often hard to read 3.  Ã‚  Ã‚  Ã‚  Ã‚  Read script a few words ahead of the keying point. 4.  Ã‚  Ã‚  Ã‚  Ã‚  Doing so will help you produce copy free of error 5.  Ã‚  Ã‚  Ã‚  Ã‚  Leave propend Page 59 1.  Ã‚  Ã‚  Ã‚  Ã‚  Kacy and Zoà « may visit their parents on labor day 2.  Ã‚  Ã‚  Ã‚  Ã‚  Gus asked if Memorial Day comes at the end of May. 3.  Ã‚  Ã‚  Ã‚  Ã‚  The Fourth of July horns the Americans Revolution. 4.  Ã‚  Ã‚  Ã‚  Ã‚  Bastille bay is in honor of the French revolution. 5.  Ã‚  Ã‚  Ã‚  Ã‚  When you were in Nevada, did you visit Hoover Dam? 6.  Ã‚  Ã‚  Ã‚  Ã‚  Did he see Paris from the top of the Eiffel tower? 7.  Ã‚  Ã‚  Ã‚  Ã‚  Val drove through the black hills in South Dakota. 8.  Ã‚  Ã‚  Ã‚  Ã‚  We canoed down the Missouri river near Sioux City. 9.  Ã‚  Ã‚  Ã‚  Ã‚  Jemel lives at bay towers near Golden Gate Bridge. 10.our store is now in midtown plaza on Kenwood road. Page 63 1.  Ã‚  Ã‚  Ã‚  Ã‚  Rough draft is keyed copy with handwritten changes. 2.  Ã‚  Ã‚  Ã‚  Ã‚  Special marks are used to show changes to be made. 3.  Ã‚  Ã‚  Ã‚  Ã‚  First read a sentence noting changes properly. 4.  Ã‚  Ã‚  Ã‚  Ã‚  Next, check to see that you made. 5.  Ã‚  Ã‚  Ã‚  Ã‚  If not correct your work or key the sentence again. 6.  Ã‚  Ã‚  Ã‚  Ã‚  Read rough draft slightly ahead of the keying point. 7.  Ã‚  Ã‚  Ã‚  Ã‚  Doing so will help you to make all the changes right. 8.  Ã‚  Ã‚  Ã‚  Ã‚  You soon will key often from script and rough draft. Page 63 Straight Copy   Ã‚  Ã‚  Ã‚  Ã‚  No matter what form the copy tacks, keep the eyes on it as you key. If you look away from the copy, you will lose a second or two. If you look away too often your speed will drop by a word or two. Script Fix you eyes on the copy now and keep them there as you key this copy. Be quick to recognize looking away will drop you speed. Rough draft Read script and rough draft with real care to avoid a Major error in keying. Read a little ahead of where your keying The quiz on the 18th will be on pages 11 to 18 and 81 to 88. The quiz on the 18th will be on pages 11 to 18 and 81 to 88.

Gmf (Genetically Modified Food) Essay

â€Å"Genetically modified foods† is the term most commonly used to refer to crop plants created for human or ani mal consumption, which have been modified in the laboratory to enhance desired traits or improved nutritional content. The enhancement of desired traits has traditionally been undertaken through breeding, but conventional plant breeding methods can be very time consuming and are often not very accurate. Genetic engineering, on the other hand, can create plants with the exact desired trait very rapidly and with great accuracy. Development. GM foods were first put on the market in the early 1990s. Typically, genetically modified foods are plant products: soybean, corn, canola, and cotton seed oil, but animal products have been proposed. The first commercially grown genetically modified whole food crop was the tomato puree (called FlavrSavr), which was made more resistant to rotting by Californian company Calgene. Currently, th ere are a number of foods of which a genetically modified version exists. What plants are involved? Some foods have been modified to make them resistant to insects and viruses and more able to tolerate herbicides. Crops that have been modified for these purposes, with approval from the relevant authorities, in a number of countries, include: maize, soybean, oilseed rape (canola), chicory, squash, potato. Some of the advantages of GM foods: There is a need to produce inexpensive, safe and nutritious foods to help feed the world’s growing population. Genetic modification may provide: ï‚ · Better quality food. ï‚ · Higher nutritional yields. ï‚ · Inexpensive and nutritious food, like carrots with more antioxidants. ï‚ · Foods with a greater shelf life, like tomatoes that taste better and last longer. ï‚ · Food with medicinal benefits, such as edible vaccines – for example, bananas with bacterial or rotavirus antigens. ï‚ · Crops and produce that require less chemical application, such as herbicide resistant canola. Some of the disadvantages of GM foods: Food regulatory authorities require that GM foods receive individual pre-market safety assessments. Also, the principle of ‘substantial equivalence’ is used. This means that an existing food is compared with its genetically modified coun terpart to find any differences between the existing food and the new product. The assessment investigates: ï‚ · Toxicity (using similar methods to those used for conventional foods). ï‚ · Tendency to provoke any allergic reaction. ï‚ · Stability of the inserted gene. ï‚ · Whether there is any nutritional deficit or change in the GM food. ï‚ · Any other unintended effects of the gene insertion. Economic concerns: Bringing a GM food to market is a lengthy and costly process, and of course agri -biotech companies wish to ensure a profitable return on their investment. Many new plant genetic engineering technologies and GM plants have been patented, and patent infringement is a big concern of agribusiness. Yet consumer advocates are worried that patenting these new plant varieties will raise the price of seeds so high that small farmers and third world countries will not be able to afford seeds for GM crops, thus widening the gap between the wealthy and the poor. One way to combat possible patent infringement is to introduce a â€Å"suici de gene† into GM plants. These plants would be viable for only one growing season and would produce sterile seeds that do not germinate. Farmers would need to buy a fresh supply of seeds each year. However, this would be financially disastrous for farmers in third world countries who cannot afford to buy seed each year and traditionally set aside a portion of their harvest to plant in the next growing season. How are GM foods labeled? Labeling of GM foods and food products is also a contentious issue. On th e whole, agribusiness industries believe that labeling should be voluntary and influenced by the demands of the free market. If consumers show preference for labeled foods over non -labeled foods, then industry will have the incentive to regulate itself or risk alienating the customer. There are many questions that must be answered if labeling of GM foods becomes mandatory such as; are consumers willing to absorb the cost of such an initiative? If the food production industry is required to label GM foods, factories will need to construct two separate processing streams and monitor the production lines accordingly. Farmers must be able to keep GM crops and non -GM crops from mixing during planting, harvesting and shipping. It is almost assured that industry will pass along these additional costs to consumers in the form of higher prices. Food labels must be designed to clearly convey accurate information about the product in simple language that everyone can understand. Conclusion: Genetically-modified foods have the potential to solve many of the world’s hunger and malnutrition problems, and to help protect and preserve the environment by increasing yield and reducing reliance upon chemical pesticides and herbicides. However, we must proceed with caution to avoid causing unintended harm to human health and the environment as a result of our enthusiasm for this powerful technology.