MercadoLibre Case Study Management Report Essay

MercadoLibre Case Study Management Report - Essay Example Introduction MercadolLibre is a Portuguese website company which is dedicated to online auctions and to e-commerce. It is basically eBay’s Latin American Partner. In Latin America it is the number one e-commerce site. It has its headquarters located in Ciudad de Buenos Aires, Argentina. The literal market of MercadoLibre is free market in Spanish. Anyone can register in this site and use it to do online auction. The organisational culture in MercadoLibre is an open one. It serves as their backbone. Their IT infrastructure is also an open source one. It uses Varnish cache to enhance the web experience of their user. Such infrastructure gives a better performance as compared to their competing products. Basically varnish stores the web pages in the memory and hence they get loaded faster. Discussion This part of the study will discuss about the business environment and strategy of the organization. In addition to this, the strategy of MercadoLibre has been critically evaluated i n this part of the study. Business Environment Analysis Porter’s five force model and PESTLE analysis has been implemented in this study to determine the effect of environmental factors on the business process of MercadoLibre. Porter’s Five Force Analysis This analytical tool will help the organization to determine the industry opportunities and threats that can help the organization to develop future strategies. Buyers’ bargaining power Each and every Latin American country is achieving significant economic growth rate due to the globalization, technological advancement and growth of several domestic organizations. MercadoLibre is one of the emerging online trading and payment platforms in Latin America. This internet auction site has gain huge popularity due to its effective business operation strategies. Recent financial crisis and economic downturn affected the purchasing power of the people (Belz and Peattie, 2010, p. 224). Therefore, the online selling and purchasing activities in these countries have reduced. Although the organizations offers huge ranges of differentiated products for buying and selling, but affected purchasing power of people increased the threat of high bargaining power of customers or buyers for organizations within this particular industry. Suppliers’ bargaining power Suppliers’ bargaining power is quite low as the industry has reached to the growth stage of the industry life cycle recently. The business operation of this organization highly depends on the effectiveness of the supply chain network (Blenkhorn and Fleisher, 2005, p. 115). Huge availability of the suppliers can give cost effective supply chain options for the organizations. Therefore, it can be stated that the threat of suppliers’ bargaining power is not high. Threat of Substitutes Threat of substitute for MercadoLibre is quite low as the market demand for online purchasing and selling or internet auction is significantly incre asing among the target customers. This virtual market place gained huge popularity in recent past due to technological advancement. The demand for traditional purchasing and selling process is reducing. Therefore, it can be stated that the threat of substitute is low for the suppliers (Etzel, Stanton and Walker, 1997, p. 74). Threat of New Entrants Threat of

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

Poland - Essay Example The national language of Poland is Polish and its total covered area is around 312,685 sq Km. (Poland Introduction, 2001) Poland is known as the most religious country of Europe. About 90% of the total population is the Roman Catholic, while Protestants, Jehovah's witnesses, Polish Orthodox, Polish Catholics, Muslims and Jews are in minorities. The Eastern Orthodox are 1% of the total population while Protestants are 0.3% and others are 0.8%; according to an estimation made in 2002. The last pope of the Roman Catholic church Pope John Paul II also belongs from Poland - before the Pope Benedict. The Roman Catholic religion is dominated in the country and it is also a part of the curriculum - in the education sector. (Religion in Poland, 2008) Economically, Poland is a sound country and growing day by day. The Poland's Gross Domestic Product (GDP) increased 6.1% in 2006. After the rejection of communism, Poland adopted the policy of liberalism which successfully worked and supported the economy to rise. The liberal laws helped in the development of the private sector and many medium and small industries were privatized. Several important sectors were also privatized including; steel, coal, railway and power generation. In the year 2000, the national telecom was also privatized and sold to France which is considered as the biggest privatization ever made, by the year 2007. Main Industries include; mining, textile, shipbuilding, glass and beverages. With the growing GDP rate since 1993, Poland has potential to become largest food producer among the European Union countries in agriculture sector. Various private farms are producing fruits, vegetables and specially potatoes. Poultry, eggs, and pork are also monitored by the s ame farms. The currency of Poland is called Zloty. Poland is continuously bringing reforms in its economic policies to fulfill the criteria of adopting euro (European single currency). It is said that by 2012, Poland will be able to adopt euro. In Poland, salaries are low and the ratio of unemployment is high, one of the reason is; the economic crises in the Soviet Union and Germany (the biggest trade partners of Poland). People have started to move to other European Union countries mostly to UK and Ireland. With the continuous reforms it is expected that soon this problem will also be overcome. (Diziadosiz and Stasiak, 2004) Role of Women During the era of 1970, the work force of Poland basically comprises of women. Poland government gave more opportunities to female in education and employment. In many major professions, the rate of women was higher than men. During 1980, most of the medical practitioners were women. On the other hand, women were kept completely at bay from the posts of power and authority. However, Poland elected its first Prime Minister, Hanna Suchocka in 1992, but the interesting fact is that there was not a single woman in her government. During the same year another woman, Eva lelowska became the head of the National Bank of Poland. Though, women played remarkable role on all the labor positions but male dominance always remain hurdle for them to reach and gain higher positions. State institutions helped many women to do two full time jobs due to the lack of their

Theories on Employee Relations

Theories on Employee Relations Unitarist, Pluralist and Marxist perspective have been described for understanding and analyzing employee relations. Each of them provides a different interpretation towards workplace conflict, the role of unions and job regulation (Edwards, 2003). In other words, those three perspectives hold different views against conflict in the employee relations. The following paragraphs will introduce three perspectives one by one. After that, it will summarize the differences among them. Unitarist perspective Seeing from the Unitarist perspective, the organization is regarded as an integrated and harmonious group of people with one loyalty culture. Specified explanations are as follows. Such an organization attaches much importance to mutual cooperation. Moreover, all employees within the organization share a mutual purpose. In addition, this perspective similar to paternalism has a high requirement for the loyalty of all employees. The management of such an organization is outstanding due to its emphasis and application. For this reason, it has been concluded that trade unions are not necessary for the mutual exclusiveness of the loyalty between organizations and employees. However, the conflict on employee relations is considered pathological and disruptive outcome caused by interpersonal friction, communication breakdown, as well as agitators (Kaufman, 2004). Pluralist perspective From the perspective of Pluralist, organization is made up of various sectional groups. Each group has its legal loyalties, goals and leaders. Particularly, management and trade unions are two remarkable sectional groups in the Pluralist perspective. As a result, the main job responsibility of management is not enforcement and control but persuasion and coordination. However, trade unions are acted as lawful delegates of employees. The conflict is inevitable here and the conflict in the Pluralistic perspective is solved by collective bargaining. Generally speaking, conflict is always associated with bad things. However, conflict if being managed well can also take place evolution and positive change from the perspective of Pluralism (Kaufman, 2004). Marxist perspective Marxist perspective is also called radical perspective. This perspective is to reveal the nature of the capitalist society. It thinks that workplace relations are against the history. It recognizes inequalities in power in the employment relationship and in wider society as a whole. Consequently, conflict is perceived as an inevitable result. Whatà ¢Ã¢â€š ¬Ã¢â€ž ¢s more, a natural response regarding workers against the capitalism exploitation is seen as trade unions. The managementà ¢Ã¢â€š ¬Ã¢â€ž ¢s position would be improved by institutions of joint regulation from the view of Marxism if having the periods of acquiescence, because they suppose rather than challenge the proceeding of capitalism (Hyman, 1975). Differences among three perspectives According to the descriptions toward three perspectives, it is obviously that they have different understandings against conflict. The Unitarist view perceives conflict as a word with derogatory sense and it puts forward three reasons of generating conflict such as agitators, interpersonal friction and communication breakdown. It employs a paternalistic approach, so it is short of the conflict between capital and labor which is the focus of Marxist perspective. Moreover, it does not refer to the solution. On the contrary, the Pluralist view indicates that collective bargaining is the way of tackling conflict. Another difference lies in that sometimes conflict can be positive. It implies the importance of conflict management. It can be seen that the Pluralist view pays much attention to conflict resolution and how to how to manage conflict. Moreover, it considers that the power between parties with different interests is equal, which is just opposite to the Marxist perspective. Actual ly, the Marxist view is very radical. From its point of view, the inevitability of conflict comes from the inequalities of powers caused by capitalism exploitation. That is to say, different from Unitarist perspective, the Marxist perspective gives different reasons of bringing about conflict. Appropriate perspective for analyzing employee relations in the UK In this part, it will firstly describe the development process of employee relations in the UK. Afterwards, it will prove that three perspectives can be applied to analyze the British employee relations but the Pluralist perspective is the most appropriate view for analyzing British employee relations. According to the definition of collective bargaining by International Labor Organization, one party of collective bargaining is one employer, some employers or one or several employer organizations while the other party is one or several worker organization (Herman, 1998). It is obviously that the collective bargaining is not feasible without the union of workers. In Medieval England, the relationship between employers and employees was equal but not class relations. As usual, most of competent employees would live in a separate house or married the daughter of employers. The sprout of the capitalist way of production provided possibility for the emergence of industrial relations. The distinction of manufacturing rights and power of management, the division of employers and employees, as well as the existence of a great many permanent labors provided soil for the generation of the trade union. At the early stage of capitalism, there was not law or system to guarantee the basic life o f employees. In order to make a living, workers must negotiate with employers. Although a lot of inequalities existed between them, workers did not have enough countervailing power through individual negotiation or signing contract with each worker. In order to improve life and working conditions, labors gradually united and struggled with employers. At the end of 1600s, trade union emerged as the times require. Because the industrial workers did not form strong hierarchy, the primary labor movement was only limited to the range of manual workers. One of important role of the early trade union on behalf of workers was to negotiate with employers for salary, employment conditions and so on. At the end of 1700s, the collective agreement between employment labor organizations and employers came to the UK, which is the earliest collective agreement in the world (Fraser, 1999). The UK as the source origin of Industrial Revolution is also a country developing trade union movement earliest in the world (Williams and Smith, 2006). Therefore, the British labor relations system is with distinctive characteristics. In the development history of British Labor Laws, collective bargaining is regarded as an effective way to resolve labor disputes. Before the Second World War, the collective bargaining in the UK was mainly a national negotiation. The national collective agreement covered most of workers. Until 1970s, some local collective bargaining emerged. More and more employers started to withdraw from national collective bargaining. Corporate-level collective bargaining gradually occupied dominant position replacing national collective bargaining (Gospel, 1998). Moreover, the government also supported decentralized collective bargaining and the regulatory institutions such as wages council were abolished. In addition, the British law fully protected the interests of members of trade union and stated a variety of immunities against trade unions so that they would not be charged owing to strikes or other industrial actions. However, collective bargaining has begun to suffer multifarious criticisms since 1980s. Someone criticized that the collective bargaining was too disruptive, because the breakdown of collective bargaining brought about too frequently industrial actions so as to weaken domestic economic competitiveness. As a result, the coverage of collective bargaining gets smaller and smaller. According to the statistics, the coverage has already decreased from 70% in 1984 to 41% in1998 (Addison and Siebert, 2002). In any way, collective bargaining was the basis of the British employee relations for much of the 20th century. Based on the introduction of employee relations in the UK, it can be seen that the British collectivism has already went through the development process from sprout to be legal. In Medieval England, the relationship between employers and employees can be explained with the paternalistic approach. Employers and employees were loyal with the ideal of à ¢Ã¢â€š ¬Ã…“a happy familyà ¢Ã¢â€š ¬Ã‚  and did not need the trade union to solve conflicts, which is the emphasis of the Unitarist perspective. Consequently, the inequalities existed between employers and employees at the beginning stage of capitalism. Employees were exploited by employers, but they had not enough strong power to solve them. For this reason, the inequalities in power in employment relationship can be analyzed by the Marxist view. After that period of time, the trade union came into being and was firstly responsible for negotiating with employers regarding the issues of wage and employment condition. Afterwards, the collective agreement emerged in the UK with the improvement of trade union. Moreover, the diversification of employees created conditions for the expansion of trade unions and members. As a result, the form of collective bargaining was more common and was regarded as an effective solution to conflict in labor disputes, which is identical with the view of the Pluralist perspective. Employers gradually found the disadvantages of collective bargaining and less took part in the collective bargaining. As a matter of fact, the decline of collective bargaining can also attribute to the shortcomings of the Pluralist perspective which focused too much on the solution to conflict and the accommodation to change and power differences. In other words, it neglects the government influences and power differences at all employee relations levels. As a whole, the deficiencies of collective bargaining lead to its declination in the British employee relations, but its role can not be substituted for any other kind of conflict resolution. It can be concluded that the Pluralist perspective has greatly influenced the employee relations in the UK and will continue to develop its effects, which is natural to be the most appropriate perspective for analyzing the British employee relations compared with other two perspectives. Conclusion To sum up, different people have different minds. The Unitarism, Pluralism and Marxism have already expressed their views against the conflict on employee relations. However, there are some differences in their views. Three perspectives are from different angles and have different emphases. After discussing the differences among three perspectives, it has elaborated my own opinion that the Pluralist perspective is the most appropriate for the analysis of employee relations in the UK based on the development process of the British employee relations. It can be concluded from the analyses that collective bargaining with irreplaceable role is playing a less and less important role in the British employee relations with the various changes in employment and the labor force. In addition, conflict management is extremely significant for the sustainable development of organizations. People should not only focus on the conflict resolution but also pay attention to the influences of other fac tors. As a result, it is very crucial and indispensable for every organization to establish positive employee relation so as to attract and retain high-quality staff, to improve employee productivity, to increase employee loyalty, to enhance working morale, to elevate business performance, as well as to reduce absence rate (Lewis and Saunders, 2003). (1973 words)

Siddhartha Vs. A Dolls House Essay -- essays research papers

Though Siddhartha and â€Å"A Doll’s House’ share a completely different storyline, they are very much similar because of the development of the main characters throughout the two stories. Nora, from the play â€Å"A Doll’s House,† changes her image after recognizing what kind of life she was living. Siddhartha, from the book Siddhartha, becomes aware that life cannot be taught, and that it had to be experienced first-hand.   Ã‚  Ã‚  Ã‚  Ã‚  Both of the main characters seemed to have suddenly awakened from what I consider â€Å"enslavement of the mind.† I believe this because they are not free to think about things without the influence of their surrounding society. Nora notices that she is living her life in wretchedness at the end of the play, when she says, â€Å"†¦here is your ring back. Give me mine.† (Act III) This quote displays Nora’s ambition to move on in life and free her mind from the interrogations brought to her from Torvald. Siddhartha reaches this awakening while he is young. He mentions to his father about leaving the house to join the teachings of the Samanas. â€Å"†¦He moved on again and began to walk quickly and impatiently, no longer homewards, no longer to his father, no longer looking backwards.† This quote shows that Siddhartha is ready to move on and leave the everyday society, and beliefs of his parents. These quotes convey the spark of these characters’ new beliefs.   Ã‚  Ã‚  Ã‚  Ã‚  Nora, appearing as the ordinary housewife, really is not what she...

Business Class

1) Go to the Bureau of Economic Analysis's Webb site (www. bea. gov) and locate the gross domestic product data. Compare the annual figure for the last four years. What do the figures indicate for the next couple of years? In 2007 it was 4. 9%, in 2008 it was 1. 9%, in 2009 it was -2. 5%, in 2010 it was 4. 2%. 2011 is not yet out. These numbers indicated a rapid decrease and a rapid bounce back. I think for the next couple of years, the figures will rise again before a decrease comes again. ) At the Bureau of Labor Statistics' Web site (www. bls. gov) under Industries, click on Industries at a Glance to find the information about the manufacturing industry. What is the employment trend in manufacturing over the last four years (percentage change from the preceding period)? The unemployment percentage has been going down over the past four years. We are coming off of a 7. 9% unemployment rate. ) Return to the Bureau of Labor Statistics' home page and use the Search feature to find tre nds in employment for the state of Illinois. Look around the Web site to see what other information is available. Plot the trend in manufacturing employment in Illinois over the last four years. On your own, discuss what economic changes may have influenced that trend. In 2009, there was a big unemployment filing from the manufacturing industry due to job loss. That year there was about 65,000 jobs lossed in the manufacturing field. It went from 620k in January to 553k in December. It has been staying around 560k-570k over the past few years though. There are many reasons the manufacturing employment has dropped. Automation, technology, outsourcing, and other things factor in for the decline in jobs since 2009. 4)Based on the information you have gathered, write a brief summary of what may happen to company sales over the next couple years. Based on what I have gathered, company sales will increase

Exercise Physiology

Direct calorimetry uses the measurement of heat production as an indication of metabolic rate. * Indirect calorimetry estimates metabolic rate via the measurement of oxygen consumption. * Energy expenditure can be expressed in L†¢min-1, kcal†¢min-1, ml†¢kg-1†¢min-1, METs, and kcal†¢kg-1†¢hr-1. * To convert L†¢min-1 to kcal†¢min-1, multiply by 5. 0 kcal†¢L-1. * To convert L†¢min-1 to ml†¢kg-1†¢min-1, multiply by 1000 and divide by body weight in kilograms. * To convert ml†¢kg-1†¢min-1 to METs or kcal†¢kg-1†¢hr-1, divide by 3. 5 ml†¢kg-1†¢min-1. Efficiency: * Exercise work rate Efficiency decreases as work rate increases * Speed of movement* There is an optimum speed of movement and any deviation reduces efficiency * Muscle fiber type * Higher efficiency in muscles with greater percentage of slow fibers SUMMARY: Net efficiency is defined as the mathematical ratio of work performed divided by the e nergy expenditure above rest, and is expressed as a percentage. * The efficiency of exercise decreases as the exercise work rate increases. This occurs because the relationship between work rate and energy expenditure is curvilinear. To achieve maximal efficiency at any work rate, there is an optimal speed of movement. * Exercise efficiency is greater in subjects who possess a high percentage of slow muscle fibers compared to subjects with a high percentage of fast fibers.This is occurs because slow muscle fibers are more efficient than fast fibers. * Not possible to calculate net efficiency of horizontal running * Running Economy * Oxygen cost of running at given speed * Lower VO2 (ml†¢kg–1†¢min–1) at same speed indicates better running economy * Gender difference * No difference at slow speeds At â€Å"race pace† speeds, males may be more economical that females 170-188 CIRCULATORY RESPONSE TO EXERCISE Organization: arteries branch to form vessels, v essels become microscopic and form arterioles, which develop into â€Å"beds† called capillaries. Capillaries are the smallest and most numerous of blood vessels—exchange of oxygen, CO2, and nutrients. Blood passes from capillary beds to venules that move back to heart and increase in size becoming veins. Mixed venous blood= mixture of venous blood from both upper and lower body in the right side of the heart. *it represents an average of venous blood from entire body.HEART: Right/left side separated by muscular wall called interventricular septum (prevents mixing blood from sides). Valves: Bicuspid/mitral = left atrioventricular valve **atrioventriculars close when heart contracts to prevent backflow. Tricuspid= right atrioventricular valve Semilunar valve (pulmonary semilunar)- b/w right ventricle and pulmonary artery. Prevents backflow from arteries into ventricles. Aortic valve (aortic semilunar)= b/w left ventricle and aorta. Also prevents backflow†¦ Right si de pumps deoxygenated blood to pulmonary circuit so oxygen can be loaded and CO2 released.Left side pumps oxygenated blood to body via systemic circuit. RIGHT: to lungs LEFT: to body Heart sounds are due to closing of atrioventricular valves (first sound-systole) and the closing of aortic and pulmonary valves (second sound-diastole) Wall of heart is 3 layered: 1) outer layer is epicardium, 2) muscular middle layer called myocardium, 3) inner layer endocardium. Myocardium contracts to force blood out. Right and left coronary arteries supply myocardium Cardiac muscle fibers are shorter than skeletal and are branched and involuntary. Heart muscle fibers are all connected via intercalated discs- transmit electrical impulses.They are leaky membranes that allow ions to cross b/w fibers (contract together= functional syncytium). *atria contract separate from ventricles because there is a separating layer of CT *heart is only type 1, slow fiber- highly aerobic, many mitochondria (more than skeletal). Cardiac cycle: Systole- contraction phase (blood ejected) Diastole- relaxation period (arterial BP decreases– filling) There is also an atrial systole and diastole. Atrial contraction during ventricular diastole, atrial relaxation when ventricular systole. *SO there are TWO steps of heart pumping. *atria contract together, which empties arterial blood into ventricles. . 1 second and then ventricles contract to deliver blood to systemic and pulmonary circuits.*when atria relax, blood flows into them from venous circulation as they fill, pressure inside increases. Increase in HR less time spent in diastole (not as much impact on time in systole until at high HR) Arterial Blood Pressure: -greatest in arteries BP = the force exerted by blood against the arterial walls. Determined by how much blood is pumped and the resistance to blood flow. -male: 120/80, female: 110/70 systolic/diastolic dif between the two is calls â€Å"pulse pressure† â€Å"mean arterial pr essure†= av pressure during cardiac cycle. determines rate of blood flow through systemic circuit Mean arterial pressure = DBP + . 33 (pulse pressure) (DBP: diastolic blood pressure) (pulse pressure: dif between systolic and diastolic pressure) SO, if someone has bp 120/80, Mean arterial pressure= 80mmHg + . 33(120 – 80) = 93 mmHg *but this calculation is only used for cardiac cycle at rest.Hypertension- increases workload on left ventricle so cardiac mass increases, but this eventually results in diminished pumping capacity. Also increase risk for other disease/damage of body parts like brain and kidneys. 20% all US adults Factors influencing arterial BP: ) cardiac output—amount of blood pumped from heart 2) total vascular resistance – sum of resistance to blood flow by all systemic blood vessels. —blood volume, blood viscosity Mean arterial blood pressure = (cardiac output x total vascular resistance) *so increase in either will increase the mean art. BP Blood pressure increases when increase in: blood volume, HR, SV, blood viscosity, peripheral resistance. And it decreases when any of those decrease. BP regulated short term by the sympathetic NS, long term by the kidneys (bc they control blood volume). Baroreceptors- sense arterial blood pressure in carotid artery and aorta.Increase in pressure send impulses to CV control center which will decrease the sympathetic activity (lowers cardiac output and/or reduces vascular resistance lowers BP). Decrease in BP reduction of baroreceptors activity to brain CV control center increases sympathetic activity raise BP to normal Electrical Activity of the Heart: Sionatrial node (SA node)- in the right atrium (by the vena cava). responsible for spontaneous electrical activity in normal heart, it’s the pacemaker. Occurs due to decay of resting membrane potential (bc of diffusion of NA during diastole).When SA is depolarized and reaches threshold, a wave of depolarization is spread over the atria contraction! Wave of atrial depolarization needs special conductive tissue to transport it to the ventricles. This conductive tissue is called the atrioventricular node (AV node- in floor of right atrium). When blood from atria empties into ventricles, the conductive pathways branch into smaller fibers called purkinje fibers that spread the wave of depolarization through ventricle so it can contract. Electrocardiogram (ECG)- recording of electrical charges in myocardium during cardiac cycle. –ability of hear to conduct impulses.P wave- depolarization of atria QRS complex- depolarization of ventricles and atrial repolarization(during beginning of systole, aprx . 10 seconds after Pwave) T wave- ventricular repolarization (same time as QRS, but at the beginning of diastole) CARDIAC OUTPUT (Q): Q = HR X SV Regulation of heart rate: -because SA node controls HR, changes in HR involve factors influencing SA node. Most influence over HR: parasympathetic and sympathet ic NS Parasympathetic NS- acts as braking system to slow HR using vagus nerve which touches SA and AV node and releases acetylcholine decrease activity of SA and AV nodes due to hyperpolarization= reduce HR. —initial increase in HR during exrcise up to 100bpm is due to decrease in parasympathetic tone. Sympathetic fibers use cardiac accelerator nerves to innervate both SA node and ventricles.Increase HR and myocardial contraction when they release norepinephrine. –beta receptors *all beta-blocking drugs will decrease resting HR and exercise HR. CV control center regulates- pressure receptors in right atrial respond when there is increased pressure by increasing Q to reduce the BP. Body Temp also influences HR. increase temp = increase HR Regulation of stroke volume: ) end-diastolic volume (EDV aka â€Å"preload†) (volume of blood at end of diastole) 2) average aortic BP 3) strength of ventricular contraction EDV- Frank and Starling, stronger contraction with hig her EDV bc there is more stretch of ventricles. EDV influenced by rate of venous return to heart- more return= higher EDV. Venous return regulated by: 1) venoconstriction – reduced volume capacity of veins to store blood. *sympathetic control- activates organ increase HR (the parasympathetic inhibits activation decrease HR) 2) muscle pump—muscles contract and compress veins blood pushed to heart.Venous return reduced when muscles are contracted. isometric exercise, mechanical. 3) respiratory pump- breathing decreases pressure in chest and increases abdominal pressure so venous blood flows from abdominal into thorax and increases return. *more respiration in exercise Aortic pressure (mean arterial pressure/afterload)- to eject blood, pressure in left ventricle must be more than in the aorta. Increase in aortic pressure= decrease SV. Less afterload during exercise bc arteriole dilation reduces afterload. Circulating epinephrine-norepinephrine (increase Ca+ entry) and dir ect sympathetic stimulation of heart by cardiac accelerator nerves.Increase in sympathetic stimulation of heart increases SV at any level of EDV. HEMODYNAMICS: -blood flow is in a continuous loop. Physical characteristic of blood- composed of plasma (watery portion, contains ions/proteins/hormones) and cells (called the hematocrit: RBC/platelets/WBC). Hematocrit= 42% of blood (38% in college women), the rest is plasma. RBCs are largest part of a blood cell—influence viscosity. Anemia decreases RBC, so decreases viscosity Relationships among pressure, resistance, and flow: Rate of flow is proportional to pressure difference. Inversely proportioned to resistance.Blood Flow= change in pressure/ resistance -Change in pressure is the dif between the two ends of the circulatory system -resistance due to length of vessel and viscosity, and radius of vessel **Blood flow increases with increase in BP or with decrease in resistance. -during exercise blood flow increases mainly due to d ecrease in resistance with small rise in pressure. Resistance = (length x viscosity)/ radius^4 (**so radius is VERY important-vasoconstriction/vasodilation) Sources of vascular resistance: -vasoconstriction/vasodilation the greatest vascular resistance in blood flow occurs in arterioles.Pg 188 – 196 Changes in oxygen delivery to muscle during exercise: Metabolic need for O2 increases so there is an increase in blood flow to muscle- increase O2 delivery by 1) increased cardiac output and 2) redistribution of blood flow from inactive organs to working skeletal muscle. Changes in cardiac output during exercise: -cardiac output increases in proportion to metabolic rate for task -maximal cardiac output decreases after 30 yrs of age mostly bc of decreased maximal heart rate with age. Cardiac output = heart rate X stroke volume Max HR = 220 – age (years)Changes in Arterial-Mixed Venous O2 content during exercise: -change in arterial-mixed venous oxygen difference (a – VO2 diff)during exercise. It represents the amount of O2 taken from 100 ml of blood by the tissue during 1 systemic circuit. The relationship between cardiac output (Q), a – VO2 diff, and oxygen uptake is given by the Fick equation: VO2 = Q X (a- VO2 diff). Fick equation: VO2 is equal to the product of cardiac output and the a-VO2 diff. *SO INCREASE IN CARDIAC OUTPUT OR (a – VO2 diff ) WOULD ELEVATE VO2. Redistribution of Blood Flow During Exercise:Increase flow to skeletal muscles and decrease to less-active organs like liver, kidneys, GI tract. Increase in muscle blood flow and decrease in splanchnic blood flow change as a linear function of %VO2 max. -at rest aprx 15-20% total cardiac output is directed to skeletal muscles. -during maximal exercise 80-85% of total cardiac output goes to skeletal muscle (to help meet oxygen needs for contracting) -during heavy exercise % that goes to brain is reduced compared to rest. -total coronary blood flow increases due to incre ase in cardiac output -reduction of blood flow to skin and abdominal organsRegulation of local blood flow during exercise: Regulated with arterioles in skeletal muscles that have a high vascular resistance at rest (due to adrenergic sympathetic stimulation which causes vasoconstriction). This results in low blood flow to muscle (4-5 ml/min per 100g muscle) but this is still 20-25% total flow from heart. **autoregulation (an intrinsic metabolic control) -vasodilation (opens vessels) results from local changes during exercise like decrease in O2 tension, increase in CO2 tension, nitric oxide, potassium and adenosine concentrations, increase in acidity.Vasodilation reduces vascular resistance and therefore increases blood flow. Also aided by recruitment of cappilaries- at rest only 5-10% of capillaries are open, all are open during heavy exercise. **level of vasodilation regulated by metabolic need of the muscle (intensity and # of motor units recruited determines blood flow to active muscle fibers) during exercise, vascular resistance in skeletal muscle decreases and vascular resistance to flow in the visceral organs/other inactive tissue increases. *because on increased sympathetic output to these organs regulated by CV control center. increase in visceral vasoconstriction during exercise decreases blood flow to viscera by 20-30% resting value. During exercise in upright position, SV reaches plateau at 40% VO2 max, therefore, at work rate about 40% VO2 max, the rise in cardiac output (Q) is due to increased HR only.CIRCULATORY RESPONSES TO EXERCISE: HR and blood pressure at any VO2 (oxygen uptake) are higher in arm than in leg -higher HR in hot/humid conditions emotional influence- HR increase with high emotion because increase in sympathetic NS activity. Does not generally alter peak HR or blood pressure during exercise itself but does elevate pre-exercise HR. ransition from rest to exercise- increase in HR and SV and cardiac output at beginning of exercise (a fter 1st second! ) then if work is constant it plateaus recovery from exercise- recovery from short-term/low intensity is rapid. Recovery after exercise better in trained individuals bc their HR doesn’t get as high. Recovery from long-term is slower because elevated body temp. incremental exercise- HR and cardiac output increase in direct proportion to O2 uptake. More O2 uptake = more blood flow to muscles. Plateau of cardiac output and HR at 100% VO2 max (no more hemoglobin to transport O2).The increase in HR and systolic BP results in increased workload on the heart (increased metabolic demand on heart estimated by: double product = HR x systolic BP) maximal exercise increases workload on heart by 500% Useful equation to tell patients with coronary artery blockage how they can exercise. **cardiac output increases because decrease in vascular resistance to flow and increase in mean arterial blood pressure. Arm vs. Leg exercise- HR and BP higher in arm because greater sympath etic outflow to heart during arm work when compared to leg work.Large increase in BP for arms because of vasoconstriction in inactive muscle groups. Large muscles (legs) have more resistance vessels dialated, so there is lower peripheral resistance and lower BP (cardiac output x resistance= pressure). Intermittent exercise- (interval training), recovery of HR and BP depends on level of fitness, environmental conditions, and duration and intensity. Recovery not complete if the temperature is high because that increases HR. with repeated bouts of light exercise, many repetitions can be preformed. Prolonged exercise- cardiac output at constant level.SV declines while HR increases because the increase (cardiac output constant bc HR increases and balances SV decrease). Cardiovascular drift= increase in HR and decrease in SV during prolonged exercise. , it is due to rising body temp and reduction in plasma volume. Reduction in plasma volume reduces venous return to heart and thus decrease in SV REGULATION OF CARDIOVASCULAR ADJUSTMENTS TO EXERCISE –increase in sympathetic stimulation of heart and vasodilation of arterioles and increase resistance of vessels in less-active areas= increase cardiac output so that blood flow to muscle matches metabolic needs.Central command- CV change due to centrally generated cv motor signals **also modified by heart mechanoreceptors, muscle chemoreceptors, muscle mechanoreceptors, and pressure-sensitive receptors (baroreceptors) â€Å"tuners† during exercise: muscle chemoreceptors- muscle metabolites (K, lactic acid, etc. ) muscle mechanoreceptors- force and speed of muscular movement baroreceptors- change in arterial BP- regulate arterial BP Page 267-269, 277-280 VO2 max = HR max X SV max X (a- vO2 dif)max STROKE VOLUME SV = End diastolic volume(EDV) – End systolic volume (ESV) *EDV increase ecause increase in ventricle size/increase in venous return (â€Å"preload†), increase in myocardial contractility, and decrease in resistance to blood flow out of heart (â€Å"afterload†) End diastolic volume (EDV) Left ventricle increase with endurance training bc of volume loading during exercise Plasma volume increases with endurance training (loss of plasma volume = decrease VO2 max in first weeks of detraining) **EDV increase with training. FRANK-STARLING MECHANISM: increase stretch of ventricle = increased SV Cardiac contractility- strength of contraction when fiber length, afterload, and HR are constant.Afterload- peripheral resistance against which the ventricle contracts in order to push portion of EDV into aorta. Decrease in resistance = increase max cardiac output, SO arterial BP is unchanged (MAP = Q x TPR) **endurance training lower resistance in working muscle to facilitate higher blood flow blood pressure falls when muscles capacity for blood flow exceeds hearts ability to provide it.. —to maintain BP some of muscle mass is vasoconstricted (other is vasodialated) tra ining decrease resistance of vascular bed to match increase in max cardiac output to maintain BP Arteriovenous O2 difference: increase in difference could be due to elevation of the arterial oxygen content, or decrease in the mixed venous oxygen content. -increase capacity of muscle to extract O2 after training probably because increase in capillary density (mitochondria too) accommodate more blood flow *training-induced increase in maximal SV due to increase in preload and a decrease in afterload.Preload increased because end diastolic ventricular volume and associated increase in plasma volume. Afterload decreased because decrease in arteriolar constriction in trained muscles increases maximal muscle blood flow but no change in mean arterial BP. in young, sedentary ppl, 50% of increase in VO2 is bc of increase in systemic a-VO2 dif (due to increase in capillary density). Decrease in VO2 max when you stop training because decrease in max SV and decrease in oxygen extraction. 277-28 0 net cost of walking is ? of net cost running use pace maker test for kids field test for CRF use walking, running, stepping. Can test many ppl at low cost. Hard to measure response for some, and motivation can be a variable. VO2 max estimates from all-out run tests are based on the linear relationship b/w running speed and oxygen cost of running.VO2 max estimated in endurance test is influences by CV function and % body fat. Canadian home fitness test: submaximal, uses lowest two 8-inch steps in a staircase. Evaluates cardiorespiratory fitness using post-exercise HR. 1 mile walk test: VO2 based on age, weight, sex, time, HR improved fitness: lower HR and/or time and higher VO2 max cardiorespiratory fitness measured using: treadmill, cycle ergometer, stepping bench measured by: palpation (carotid/radial artery), stethoscope (systolic- 1st korotkoff sound, diastolic- 4th sound), ECG ncreased metabolic demand on heart estimated by: double product= HR x systolic BP -double product is estimate of myocardia O2 demand arrhythmia- irregularity in normal electrical rhythm: atrial fibrillation, premature contractions conduction disturbances- depolarization is slowed/blocked (first-degree AV block or bundle branch block) myocardial ischemia- inadequate perfusion of the myocardiumflow limitation= O2 insufficiency (angina pectoris- symptom)(ST segment depression-sign upsloping, horizontal, downsloping—downsloping is worst) teady state:HR measured over 15-30 seconds post exercise HR: measured for 10 seconds within first 15 seconds of stopping exercise, then multiple the # by 6 HR and systolic BP increase with exercise intensity * Typical measurements obtained during a graded exercise test include heart rate, blood pressure, ECG, and rating of perceived exertion. * Specific signs (e. g. , fall in systolic pressure with an increase in work rate) and symptoms (e. g. , dizziness) are used to stop GXT. VO2 max: â€Å"gold standard† to measure CRF VO2 increases wi th increasing loads on a GXT until max capacity reached- VO2 estimated based on final work rate achieved in graded exercise test- can also be estimated from HR responses to submaximal exercise using age, also consider environmental factors.Estimation of VO2 max from last work rate: Poorly fit individuals take longer to achieve the steady state at moderate/heavy work rates may overestimate the VO2 max when using formula Estimation of VO2 max from submaximal HR response: HR plotted against work rate (or estimated VO2) until termination criterion of 70%- 85% of age-adjusted maximal HR reached (220-age). careful of environmental factors- dehydration, temp, emotions, medication * VO2 max Estimation of VO2 max from Last Work Rate Estimation of VO2 max from Submaximal HR Response CRITERIA FOR ACHIEVING VO2 MAX: * Leveling off of VO2 with higher work rate <150 ml†¢min–1 or <2. 1 ml†¢kg–1†¢min–1 * Post-exercise blood lactate >8 mmoles†¢L†“1 * R >1. 15 * HR within 10 beats†¢min–1 of age-predicted maximal HR * Usefulness has been questioned * Should not expect subjects to meet all criteria * Graded Exercise Test: Protocols Treadmill Cycle Ergometer Step Test * Graded Exercise Tests: MeasurementsHeart Rate Blood Pressure ECG Rating of Perceived Exertion Termination Criteria Treadmill- don’t have to adjust for body weight in calculation because subject is carrying their own weight ( so VO2 is proportional to weight). Health or cardiac risk inventory—PAR-Q (physical activity readiness questionnaire) – heart condition, pain in chest when doing physical activity, lose balance/dizziness/lose consciousness, bone/joint probs, drugs/meds for BP or heart condition * Estimating VO2 max * Based on extrapolating submaximal HR during incremental test * YMCA protocol

Better Living Through Genetic Engineering essays

Better Living Through Genetic Engineering essays In today's society, we have made great strides towards living longer, healthier, and more productive lives. With current medical technology, we have stopped smallpox, eradicated polio, restored vision to the blind, and transplanted a human heart. Now it seems that we have made these great efforts towards a better life, we have to stop and ask ourselves where we are now going with human genetic engineering. Is genetic engineering moving faster than society is evolving? Are we as a human race prepared for all that is encompassed in the science of cloning? Or could our final goal be achieving immortality? Centrally, the issue of cloning has been a hot topic in the media mainly because it has become a technological as well as a medical breakthrough. The possibilities of cloning are innumerable that is if it works. But the other side of the coin is the ethics of the process. What happens when we master cloning of body parts and venture out to clone humans? Will this clone be someone who has feelings and mind and a spirit of its own? Will it have a soul? Genetic Engineering, the alteration of an organism's genetic, or hereditary, material to eliminate undesirable characteristics or to produce desirable new ones.(Brennan, 57) . Genetic engineering is used to increase plant and animal food production; to diagnose disease, improve medical treatment, and produce vaccines and other useful drugs (Brennan, 58). Cattle and pigs have first domesticated about 8000 years ago and through selective breeding have become main sources of meat for humans. Dogs and horses have also been selectively bre d for thousands of years for recreational purposes. Over the past 20 years, genetic engineering has been revolutionized by a new technique is known as recombinant DNA, or gene splicing, with which scientists can directly alter genetic material (Encarta, 03). Genes consist of the chemical deoxyribonucleic acid (DNA). In recombinant DNA, the DNA of one organi...