How a Bill Becomes a Law Essay

Nearly 10 percent of children in the United States suffer from asthma, according to the Centers for Disease Control and Prevention. Dealing with a chronic health condition like asthma has several significant effects on a child’s lifestyle. Childhood should be fun and carefree, but kids with asthma have to take on some very big worries and responsibilities. They need to learn which symptoms and events are likely to trigger an attack, such as cold weather, exercise, stressful situations and exposure to secondhand smoke. Kids, their families and other caregivers must all learn to recognize the signs of an attack and how to respond to it quickly, such as using a steroid inhaler during acute attacks. Some kids also take daily maintenance medications, such as bronchodilators and anti-inflammatory drugs, which may reduce the risk of future attacks. Being active is a key component of being healthy and physical activity is a major part of many kids’ lives. However, kids with ast hma often have limitations that make it difficult to participate in sports, active playground games and activities like dancing. Asthma doesn’t usually prevent kids from participating in these events, but they are often at greater risk of experiencing an asthma attack in these situations. Both the children and the adults on the sidelines need to be aware of the possibility that an asthma attack could occur and what to do if it does. Anything that makes a child stand out can cause feelings of embarrassment and even shame. Kids with asthma may fear having an attack at school, or feel uncomfortable about having to use an inhaler in the presence of their friends. They may feel left out when they can’t always participate in activities with their peers. Having any serious, chronic illness is scary, and kids with asthma need extra emotional support to develop additional coping skills. Asthma often causes missed school days and these absences from school can quickly lead to a child falling behind. Kids with asthma may need extra tutoring to keep up with their classes, and understanding teachers who are aware of their students’ health issues are crucial. In some cases, severe or frequent asthma-related illness and hospitalization may even require parents to consi der homeschooling. Parents of children who have asthma often worry constantly about their child. When a child is first diagnosed with asthma there tends to be frequent emergency room visits due to the fear of the parents for their child’s safety. This situation impacts the whole family. Places that are unhealthy for an asthma  sufferer are avoided, which can keep the other family members from having these experiences. The direct costs of asthma are estimated at more than $9.4 billion. This cost is born by individuals, families, health systems and insurance providers according to the Allergy and Asthma Advocate.

How to Find SAT Scores by High School and District

How to Find SAT Scores by High School and District SAT / ACT Prep Online Guides and Tips If you’ve found this article, I assume you’re a student or parent considering your options for your or your child’s high school education. When comparing high schools, average SAT score can be an extremely useful metric since it can give you a sense of the quality of the education and the caliber of students at that high school. There are several methods for locating a school’s average SAT score, each of which I'll outline in this post. I'll also explain in more depth why you should care about average SAT score and what it can tell you about how high schools compare. How to Find SAT Scores by High School: Your Options There are several ways to track down a high school’s average SAT score. The best option for you will depend on your home state. For all states, you can order SAT reports for graduating seniors by high school from the College Board, but it costs $95/report, and you must be a school officer (e.g. a principal or school counselor). If you're a school officer or are good friends with a school officer, you should consider this option. Unfortunately, this is the only method that will work to find the SAT scores for all schools in all states. For many states, if you’re looking for the data for public high schools, the best method is to track it down through the Department of Education’s website for your state. Later on, I’ll explain how to find a district’s or specific public high school’s average SAT score using this method. This method will guarantee you’re getting up-to-date, correct, unbiased information, but the Department of Education only has the data on SAT scores by high school for public schools. This method will not work for the following states: Alabama Arizona Arkansas Colorado* DC Hawaii Illinois* Iowa Kansas* Kentucky* Louisiana* Michigan* Minnesota* Mississippi* Missouri* Montana* Nebraska Nevada New Hampshire New Mexico North Dakota Ohio Oklahoma* Oregon South Dakota* Tennessee* Utah* Wisconsin* Wyoming* *NOTE: while these states do not provide SAT data, these states do provide ACT data. For information on how to find that data, read our guide to finding ACT scores by high school. For these states and for private high schools, you should try one of these alternate search methods: look on the high school’s website. send an email to an administrator at that high school asking for the average SAT score. send an email to the Department of Education in your state asking for the data. Google search for "[High School Name] Average SAT Score." However, the search/school websites often have unreliable or outdated information (i.e. SAT score averages from three years ago). Many schools only remember to update statistics on their website every few years, and administrators may give you the same outdated information. Also, it may take administrators or Department of Education employees a while to respond to your request, especially if they’re on summer vacation. How to Use the Department of Education’s Website to Find a School District’s or Public High School’s SAT Score Start by conducting a Google Search for your state’s Department of Education. Search â€Å"[State Name] Department of Education.† As an example, I searched for Florida’s Department of Education (see screenshot). Typically, that state’s Department of Education website should be the first search result as it was below: Once you’re on the Department of Education website, there should be a search box in the upper right-hand corner. In this search box, type â€Å"SAT score† or â€Å"SAT data.† That search should bring up the SAT data for the state (see below). Make sure you select the option to view the most recent SAT data. For example, the first link above says ACT, SAT, and AP Data. The second link says ACT, SAT, and AP Data Archive. The first link is where I’d look first for the most recent data. The ACT, SAT, and AP Data Archive link most likely provides the data from past years. The first link brought me to the page below: If you’re looking for data or a specific public high school, select the option that will show you SAT School Participation and Means. It may not be labeled the same for your state. However, it should say School in the title. This link will provide you with school specific data. If you’re looking for data to compare different school districts, select the SAT District Participation file. The district option only provides you with the average SAT scores for each district in the state (without breaking it down by high school). You’ll have to download the file to your computer (which it should start to do automatically when you click on the link). A large Excel file should open that looks something like this: What this document shows will vary by state, but all of them should list the high schools and SAT scores either as a composite score or as separate section scores (Math, Critical Reading, and Writing). In the Florida document, it provides the average section score by high school with a breakdown of average section score by race and the number of SAT test-takers by high school with a breakdown by race. To locate the schools you’re interested in, use the Command + F function on your keyboard to search the file (as I’ve done below). When you find the data for the school you’re searching for, add together the 3 mean section scores to approximate the average composite SAT score for that school. I grabbed the below numbers from the brown highlighted columns (which had the average SAT section scores for the high school) in the Florida SAT spreadsheet. 580 + 593 + 561 = 1734 If you’re having trouble accessing this SAT data for your state through the Department of Education website, I recommend you contact your state’s Department of Education (the contact information should be on the Department of Education’s website). Typically, they have a specific phone number or email to contact if you’re in search of data (which you are!). If you’re having trouble getting in contact with the Department of Education or if you want information on private high schools, then I’d recommend you reach out to the high school administrators or, as a last resort, try doing a Google Search for "[High School Name] Average SAT Score." Though, as I mentioned above, websites and administrators may give you outdated information. Why Does a High School’s Average SAT Score Matter? You should care about a high school’s average SAT score because the SAT measures not only intelligence but also perseverance. For the SAT, student perseverance in SAT preparation can drastically change their score. If a student has just slightly above average intelligence, with enough SAT preparation, he or she could get a perfect score on the SAT. Through extensive studying and practicing of test content and test format, test-takers can do very well without being geniuses. If a high school’s average SAT score is high, it suggests 2 things: the quality of education is better and the students at that high school care more about their education (or more specifically the pursuit of higher education). Since the SAT does measure your intelligence to some degree and your education is responsible for how much innate intelligence you possess, the better the quality of education you receive, the better you’ll perform on the SAT. However, as I said earlier, your SAT score is also affected by how much you prepare. If a high school’s average SAT score is above average, you can bet the students at that school are also more invested in their education and more committed to getting into a good 4-year college. These students likely study more and spend time preparing for the SAT. If you're concerned about your child receiving a quality education and being surrounded by hard-working students, consider sending them to a school or school district with a higher average SAT score. Devil’s Advocate: Why Shouldn’t You Care About Average SAT Score? While SAT score can be an indicator of education quality and the quality of students, SAT score may not give you a full picture of the high school. Many public schools have magnet programs (or gifted programs) which you apply to that are separated from the â€Å"regular† track at that high school. These programs often have a higher caliber of student and better quality of education than the rest of the school. For example, my public high school had an International Baccalaureate magnet program. The program had rigorous qualifications to be accepted while the â€Å"regular† high school track had no entrance qualifications. As a result, I’d guess that students in the IB program had higher average SAT scores than the students on the â€Å"regular† high school track. However, the published average SAT score mixed the scores of IB students with the non-IB students at the same school. Therefore, you can’t figure out what the caliber of education and student will be within a magnet program at that school from the average SAT score. Also, as I said before, a big part of your SAT score is how much effort you put into preparing for the exam. If you attend a school with a low average SAT score, that does not mean you’re doomed to have a low SAT score. If you attend a school with a high average SAT score, that does not mean you'll get a high SAT score. No matter what high school you attend, you need to work hard and learn the test format and strategies to reach a high score on the SAT. What’s Next? If you're planning for college applications, learn about the new SAT and some general tips on how to prepare for the SAT. Before you start studying for the SAT, figure out what’s a good score for your target college. Want to improve your SAT score by 160 points? We've written a guide about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now:

7 things successful people do over the weekend

7 things successful people do over the weekend Perhaps you picture financially successful people jetting off to Ibiza for the weekend. Or maybe the truly accomplished spend their free time writing novels over Sunday brunch? Whatever your vision of success, the time the weekend offers is valuable to everyone- and some of us are definitely squandering it. Let’s explore a few simple ways you can spend the weekend time to become the best version of yourself. UnplugSuccessful people finish their tasks, then leave work behind. Stress from work can eat into your weekend if you let it, rendering the time useless. There’s nothing worse than an unfinished task gnawing at you or work emails reminding you what you need to do once Monday rolls around. If you set clear work-life boundaries, especially with your tasks and tech, it will result in fewer nuisances over the weekend and a better focus during actual work hours. Really, ask yourself- can’t this email wait until Monday?RestBelieve it or not, successful people do ha ve downtime. No one can run with all cylinders firing all the time; if you tried, you would burn out quickly. Successful people are good at scheduling themselves during the work day, which includes scheduling break time. Maximizing a successful weekend means taking that time to recover from the work week. Whether it’s in the form of meditation exercises, getting lost in a good book, or simply getting a couple good nights of sleep, prioritizing rest helps you recharge for the week to come.Challenge yourselfWhy not run the extra mile? Exercise is just as important for the mind as it is for the body. As with rest, you maximize your potential when your body and brain get a boost from physical fitness. But a successful person might take it up a notch beyond the stationary bike at the gym. They challenge themselves to go further: hike a mountain, train for a triathlon, take up kickboxing, or simply try something new they’ve never done before. When exercise is about striving towards a goal or making new discoveries, it fosters the kind of dynamism that make successful people excel.Develop other talentsSuccessful people can possess a laser-like focus on their goals, but highly successful people don’t just excel in their field; they likely have talents in other areas. Diversifying is not just for the financial portfolio. Art, music, or learning a foreign language helps you to challenge yourself mentally and to develop a healthier, balanced brain. The drive that helps you succeed can be used to help you find fulfillment and harness talent in other aspects of life.SavorOn the weekend, successful people make the most of their time- not by filling every second with action, but by enjoying what you can while you can. It’s the difference between savoring the flavor of coffee vs. guzzling it down like diesel fuel. Making the most of the seasons, getting outdoors, and enjoying family time are important ways to recharge over the weekend.Let the back- burner workSometimes your best ideas come to you when you’re not actively working. Innovation can be brewing in the back of your mind while you’re busy cultivating a life outside of work. Successful people are on the lookout for those ideas, ready to capture them- which means taking time away from the grind.Plan out the weekendSo how do you rest, challenge yourself, develop a new talent, unplug, and spend family time all in one weekend? It’s no secret that successful people plan out the hours of their work day to meet goals efficiently. Why wouldn’t they plan the weekend too? If you’re torn between weekend goals, planning recreational activities ahead of time helps you get the most out of the day. Just remember: the planning shouldn’t be stressful. The most successful weekend is the one you enjoy.

Value chain for carrefour company Essay Example | Topics and Well Written Essays - 250 words

Value chain for carrefour company - Essay Example This ensures that the company meets the needs and requirements of its many customers. In order to secure customer loyalty and competitive advantage, Carrefour offers its customers with a wide selection of products at best prices. Carrefour operations focus on providing products that meet the needs of a wide range of customer requirements. The retailer has every store format that meets the needs of its customers and copes with changing market trends. Carrefour has hypermarkets, supermarkets, convenience stores, cash and carry stores (Carrefour, 2012). The company uses current technologies and innovations to strengthen its operations. Carrefour seeks to offer the best range of products and services to its customers. The company’s convenience stores offer convenient services and practicality to its customers. Carrefour’s operations seek to meet the requirements of its customers. Carrefour uses Electronic Data Interchange system for procurement of its products. The company makes these products available to customers through a variety of stores worldwide. Carrefour human resource management ensures that all personnel provide quality services to customers all over the world. This is by strengthening human resource department and customer relations. Carrefour combined with See Beyond to implement and install integrated composite application network software. This was to enhance its operations and deliver quality services and goods to its customers. The software would allow Carrefour to customize its operations to various local conditions. Using the software, Carrefour would integrate its stores, distribution centers and local supply chain partners all over the world. Carrefour strengthened its inbound logistics by giving its managers the freedom to buy products from local suppliers. This increases customer loyalty thus, offering the company competitive regional advantage in different areas (Carrefour,

Virtual Realities Essay Example | Topics and Well Written Essays - 1750 words

Virtual Realities - Essay Example NASA's mandate is to address three elements before introducing a new training modality: reduce training costs, improve safety and improve astronaut performance. Any new technique needs to demonstrate superiority in at least one of these parameters. It is important to note that there is a significant 'S-curve' effect in adopting any new methodology: lots of effort going in, then significant payback as the new methodology is adopted and demonstrates greater productivity. One can look at NBS as a 'perfected' technology, one in which a lot more effort will not improve the methodology very much. If, on the other hand, IVR can be shown to be superior at present, the 'S-Curve' effect dictates a greater improvement in the future. NBS has been established since the 1960's to help train astronauts on EVA. There is therefore a substantial record of learning times on specific tasks, which can then be correlated using real spacewalk experience. With over 30 astronauts who have gone through the NBS training, then the actual EVA experience, we therefore have a database to establish four elements: Two elements: cost to train and effectiveness, can be measured on NBS in a fairly straightforward way. Safety, however, can only be subjectively addressed. This is because there have been no significant safety problems that have led to the loss of an astronaut or a hazard that has stopped an entire mission. In this case, a 'score sheet' for NBS would look as follows: On the ground In space Cost per trained astronaut $/astronaut N/A Tasks performed effectively % of tasks performed effectively % of tasks performed effectively Tasks performed safely Subjective rating (1-10) Subjective rating (1-10) By comparing on-the-ground NBS scores with in-space actual scores, we can therefore 'normalize' the NBS effectiveness and safety results to correlate them with in-space EVA results. Each of the tasks judged to be important can be thus scored, and a complete score for all NBS tasks for eventual EVA tasks can be evaluated and scored, as follows, one score sheet each for effectiveness and safety: Effectiveness Score Sheet (example) Ground Space % achieved Weighting 1-10 Activity 1 95% 85% 85/95= 89% 9 Activity 2 99% 98% 98/99=99% 6 . . . By weighting each task in regards to its importance to the mission, NASA can come up with an overall weighted score which allows for establishing the effectiveness of the training, and how much additional improvement can be made per task, and in overall EVA tasks performed. The three ways to use this are: 1. Establish the effectiveness of training using NBS on the eventual results. 2. Create a 'score' which normalizes NBS results for use when looking at IVR, and 3. Establish which areas have the greatest potential for improvement, thereby increasing overall scores. The above scoring approach works for both the safety

Civilization or people Term Paper Example | Topics and Well Written Essays - 1500 words

Civilization or people - Term Paper Example This essay attempts to prove that Hannibal’s victory at the Battle of Cannae should be attributed to the Carthaginian general’s tactical brilliance, and not to mere luck (i.e. the Roman army was seriously weakened by earlier battles). If Hannibal had exploited his triumph by attacking Rome, the Roman historian Livy believes, the Romans would have been obliged to bring peace claims. However, Hannibal decided not to attack Rome at the moment. Livy believes that this judgment was the ‘salvation of the Roman state.’1 The Battle of Cannae In 217 BC, Hannibal based his army near the Adriatic coast and kept on destroying villages in southern Italy.2 Polybius recounts that Hannibal was deeply informed of the problems posed by the Italian invasion and was aware that his main predicament would be resources.3 Rome was very weak at the time because of the massive losses it sustained the year prior. Still, Rome assigned Quintus Fabius Maximus as the new leader. Because Hannibal has a mightier cavalry, Fabius rested his army in the hills in order to reverse this advantage, resorting to the attack-retreat strategy. This was shrewd and successful given the changing balance of power after the defeats at Trasimeno and Trebia4: â€Å"The Romans hovered in the vicinity of the Carthaginians, cut off stragglers and foragers, and prevented them from founding a permanent base. The strategy avoided Roman defeat and dimmed Hannibal’s glory. It successfully kept Rome’s allies from declaring for Carthage, but it aroused great opposition among Romans themselves, for their state had thrived on a tradition of offensive warfare.†5 However, this was only a brief success. Fabius tried fearlessly to attack the Carthaginians in Falernia. He made sure that Hannibal was caught off guard. That moment, seeing his position as hopeless, Hannibal brought together all the animals in his encampment. He attached flares to each of them and made them attack the Roman encampment. Fear and bewilderment followed. Masked in darkness, with terror raging in the Roman encampment, Hannibal withdrew his whole army of 70,000 soldiers without any fatality on his side.6 Fabius had successfully held back Hannibal for six months, but the Senate decided to end his tenure as commanding officer and assigned two ambassadors, Varro and Paulus. They had realized that to confront Hannibal with not enough advantage would lead to a definite tragedy. Hence, they amassed a huge army: â€Å"Rome assembled the largest army they had ever placed in the field, eighty thousand infantry, and seven thousand cavalry.†7 Hannibal passed through the Aufidus River. The river was actually a barricade in case of defeat. Hannibal planned to take advantage of this positioning to tempt the Roman army to attack. Another lure, even though unintended, was that all of the elephants of Hannibal had been wiped out. It would be a war between two remarkably trained armed forces, th e Carthaginians being outnumbered by the Roman army.8 Both the Roman and Carthaginian armies were organized in traditional order, the cavalry on both flanks and the infantry in the middle. However, Hannibal placed his less reliable Spanish and Gauls foot soldiers at the forefront, while keeping his powerful African infantry on both flanks. This worked as bait for the attacking Roman army, who attacked the Spaniards and Gauls, pushing them, just like what Hannibal had planned. As a result, the U-shaped Carthaginian formation became bowl-shaped,

Role of Nitric Oxide in the Effect of Nebivolol

Role of Nitric Oxide in the Effect of Nebivolol ORIGINAL RTICLE ROLE OF NITRIC OXIDE IN THE EFFECT OF NEBIVOLOL ON ISOLATED TRACHEAL MUSCLE OF GUINEA PIG Asma Shaukat, Naila Abrar*, Ayesha Naureen**, Muhammad Nawaz*** Background: The use of beta blockers is limited by their ability to produce bronchospasm in asthmatics. Third generation ÃŽ ²-blockers like Nebivolol may show better tolerability because they may augment the release of nitric oxide (NO) from endothelial cells. However the involvement of NO in the respiratory effect of Nebivolol remains controversial. The present study, carried out on isolated tracheal muscle strips of guinea pigs, was designed to explore this controversy. Method: Varying concentration of histamine ranging from 10‑7 M to 10‑3 M were used to plot a concentration response curve on the isolated tracheal muscle strips of guinea pig and was used as a control. The same concentration response curve was plotted in presence of a fixed concentration of Nebivolol 106 M and then again in presence of a fixed concentration of L-Nitro Arginine Methyl Ester (L-NAME) 104 M and Nebivolol 106 M together in a series of experiments using six sets of isolated tracheal muscle strips in each case. Results: Nebivolol did not produce any significant shift in the concentration response curve while in the presence of L-NAME, Nebivolol shifted the histamine concentration response curve upwards and to the left. Conclusion: Nebivolol does not augment the histamine induced contraction of respiratory smooth muscle of guinea pig but in the presence of Nitric Oxide inhibitor L-NAME a significant augmentation of the same curve occurs, indicating a role of NO in the sparing of respiratory smooth muscle by Nebivolol. Keywords: Nebivolol, L-NAME, Concentration response curve, Tracheal muscle INTRODUCTION Pulmonary diseases with bronchial hyperactivity can be worsened or even precipitated by ÃŽ ²2 adrenoceptor blockage more commonly seen with non-selective ÃŽ ²-blockers.1 Nebivolol is a third generation à ¯Ã‚ Ã‚ ¢-blocker which may have advantage over classical à ¯Ã‚ Ã‚ ¢-lockers due to its sparing effect on tracheal muscle attributed to its ability to augment the release of NO from endothelial cells.2,3 The potent effects of NO on vascular smooth muscle and its presence in major conducting airways raises the possibility that it could contribute to the regulation of airway smooth muscle tone.4 However, the involvement of NO in the sparing effect of nebivolol on respiratory muscle is still controversial. Dal Negro et al, and Clini et al have reported in their in vivo study that single daily dose of nebivolol does not affect the production of exhaled NO in patients with mild to moderate asthma.5,6 Still there are some studies which report that increase in NO release by nebivolol may contribute to its respiratory effects.1,7 All the aforementioned review of literature therefore reveals the fact that there is no consensus on the role of NO in the respiratory effects of nebivolol and needs further elucidation. The present study was therefore aimed to explore the role of nitric oxide in modulating the effect of nebivolol on tracheal muscle of guinea pig. MATERIAL AND METHODS The present study has been conducted on the isolated tracheal smooth muscle of 24 guinea pigs (male and female) of Dunkin Hartley variety weighing 500 to 600 grams. Ethics Committee approval of the protocol was obtained. The animals were housed at animal house of Army Medical College, Rawalpindi at room temperature, and were given tap water ad libitum and were fed with a standard diet. Krebs Henseleit solution was used as the nutrient solution the composition of which per 1000 ml is: NaCl 118.2 mM, KCl 4.7 mM, MgSO4.7H2O 1.2 mM, CaCl2 2.5 mM, KH2PO4 1.3 mM, NaHCO3 25.0 mM, Dextrose 11.7 mM. Solutions of all drugs were prepared in the distilled water except for nebivolol the solution of which was prepared in Dimethyl sulphoxide since nebivolol is highly lipophilic and insoluble in water.8 The trachea was obtained from guinea pigs and preserved in Kreb’s solution. Rings, 2–3 mm wide were formed from it and cut into strips by a longitudinal cut on the ventral side opposite to the smooth muscle. The strip was then suspended in a tissue bath of 50 ml capacity, containing Kreb’s solution at 37  ºC and was aerated with oxygen continuously. Its one end was attached to the oxygen tube while the other end was connected to an isometric force displacement transducer. The tissue was equilibrated for 45 minutes against an imposed tension of two grams. A tension of one gram was applied to the tracheal strip continuously throughout the experiments.9 The trachealis muscle activity was recorded through the transducer on 4-channel oscillograph by adding different concentrations of histamine, i.e., 10-7 to 103 M with an interval of 10 minutes between each concentration. Six experiments were performed and the mean response for each concentration was worked out. A c oncentration response curve was obtained by plotting the percent contraction against the logarithm of concentrations. In the second group tracheal muscle strips were pretreated with fixed dose of nebivolol (106 M) for 15 minutes while in third group trachea was pretreated with L-NAME (104 M) for 15 minutes and then the same procedure was followed for different concentrations of histamine.10 In the fourth group the tracheal muscle was first pretreated with fixed concentration of L-NAME for 15 minutes followed by nebivolol again for 15 minutes. Then the same procedure was followed. The results have been expressed as Mean ±SEM using Microsoft Excel. The differences between the observations were considered significant if the p-value was less than 0.05 by using Student’s t-test. RESULTS Group-1 was taken as the control group and percent response with 103 M in group-1 was taken as 100% and responses with other concentrations were compared with it (Table-1). Table-1: Comparison of Group 1 with Group 2 Table-2: Comparison of Group 1 with Group 3 Table-3: Comparison of Group 2 with Group 4 DISCUSSION From the above findings, it is inferred that nebivolol has no significant effect on histamine-induced contractions of tracheal smooth muscle. These findings support the results of in vivo study whereby nebivolol, both acutely or chronically administered, did not affect airway responsiveness to inhaled histamine in rabbits.7 Similar findings have been reported in other in vivo studies. In a study conducted by De Clerck et al., (1989) it was reported that nebivolol decreased heart rate without significantly increasing pulmonary reactivity to histamine. 11 In this study some aspects concerned with the mechanisms that may be responsible for the lack of bronchoconstrictor effect of nebivolol on tracheal smooth muscle were explored. There may be many possible mechanisms which can explain the sparing effect of nebivolol. It is the most selective à ¯Ã‚ Ã‚ ¢1-adrenoceptor antagonist currently available for clinical use; its à ¯Ã‚ Ã‚ ¢1 selectivity is 3.5 times more than bisoprolol which was previously considered as the most cardioselective à ¯Ã‚ Ã‚ ¢ blocker. Beta 1 receptor selectivity is an important determinant of less incidence of bronchoconstriction and other adverse effects seen with cardioselective à ¯Ã‚ Ã‚ ¢ blockers.3 However several in vivo and in vitro studies have shown that cardioselective blockers such as atenolol and metoprolol do increase airway hyperresponsiveness, though to a lesser extent. De Clerck et al, (1989) compared the bronchoconstrictor effects of atenolol, nebivolol and propranolol in guinea pigs and they reported that bronchoconstriction was greatest with propranolol followed by atenolol while nebivolol had sparing effect.11 So the different effect of nebivolol can not be fully explained by its à ¯Ã‚ Ã‚ ¢1 selectivity.7 Another possible mechanism is that the effect of nebivolol may be because of partial agonist activity at à ¯Ã‚ Ã‚ ¢2 receptors but several studies have shown that nebivolol lacks partial agonist activity at à ¯Ã‚ Ã‚ ¢2 receptors.12 Therefore, this mechanism does not seem to be plausible. Nebivolol has been reported to modulate the endogenous production of NO.1 Nitric oxide is an important endogenous bronchodilator and is generated by a family of NO synthase isoforms in the airways.13 Considering the potential role of endogenous NO in the control of airways, its role was evaluated in the effects of nebivolol. For that purpose, L-NAME which is a competitive inhibitor of nitric oxide synthase was used. In one group effect of histamine was studied on tracheal muscle strips pretreated with fixed concentrations of L-NAME (10-4M) and its curve was compared with curve of control group. The difference was statistically insignificant indicating the absence of any effect of L-NAME on histamine induced contraction of tracheal muscle. In another group, the isolated tracheal muscle of guinea pig was pretreated with fixed concentrations of L-NAME (10-4M) and nebivolol (10-6M) respectively and then the effects of histamine were studied on this tissue model. At all the concentrations of histamine contraction of tracheal muscle was augmented and the p-value was 14,15 Nitric oxide that is released may interfere with the cholinergic neurotransmission either by functional antagonism on airway smooth muscle or via pre-junctional inhibition of release of acetylcholine from cholinergic nerve terminals. These findings suggest that NO indeed has some role in the sparing effect of nebivolol on the airways. This may be due to the reason that nebivolol induced-bronchoconstriction is counter balanced by the release of NO by nebivolol which causes bronchodilation resulting in the overall sparing effect of nebivolol on the airway smooth muscle. The NO-mediated inhibition of the acetylcholine-dependent bronchoconstriction may thus contribute to explain the differences between nebivolol and other à ¯Ã‚ Ã‚ ¢-blockers on the airway responsiveness. CONCLUSION NO may be responsible for sparing effect of nebivolol on airway smooth muscle. This may be due to the reason that nebivolol like classical beta blockers induces bronchospasm which is counter balanced by the relaxant effect of nitric oxide released by nebivolol thus lacking the net effect on airway smooth muscle. REFERENCES Dal Negro R. Pulmonary effects of nebivolol. Ther Adv Cardiovas Dis 2009;3:329–34. Scheen AJ. Pharma-clinics medication of the month, nebivolol Rev Med Liege 2001;56:788–91. Bundkirchen A, Brixius K, Bà ¶lck B, Nguyen Q, Schwinger RH. Beta 1-adrenoceptor selectivity of nebivolol and bisoprolol. A comparison of [3H]CGP 12.177 and [125I]iodocyanopindolol binding studies. Eur J Pharmacol 2003;460:19–26. Matera MG. Nitric oxide and airways. Pulm Pharmacol Ther 1998;11:341–8. 5. Dal Negro RW, Tognella S, Pomari C. Once daily nebivolol does not reduce airway patency in patients with COPD and arterial hypertension. Clin Drug Invest 2002;22:361–67. 6. Clini E, Bianchi L, Pagani M, Ambrosino N.. Endogenous nitric oxide in patients with stable COAD: Correlates with severity of disease. Thorax 1998;53:881–3. Agostino BD, Gallelli L, Falciani M, Fici F, Mangrella M. Nebivolol and airway responsiveness in the rabbit. Life Sci 2001;68:2159–68. Quang TT, Rozec B, Audigane L, Gauthier C. Investigation of the different adrenoceptor targets of nebivolol enantiomers in rat thoracic aorta. 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