Teenagers and Drugs Essay Example for Free

Teenagers and Drugs EssayA dose is any substance (with the ejection of food and water) which, when taken into the body, alters the bodys function either physically and/or psychologically. Drugs may be legal or illegal and this be draw as marijuana, hashish, cocaine (including crack), heroin, hallucinogens, inhalants, and prescription drugs that are not used for medical purposes. Nowadays drugs are everywhere and its becoming more and more used. Drugs are common in teens and they take drugs with various reasons To have fun, to relax, to socialize, and to take risks, to relieve boredom and stress. Friends, parents, older brothers and sisters and the media can also have some influence oer a young persons decision to use drugs.The experience that a person has when using drugs will be affected by the Individual Mood, physical size, gender, personality, expectations of the drug experience, whether the person has food in his/her stomach and whether other drugs have been taken. Drug The amount used, how it is used and the strength and purity of the drug. Environment Whether the person is using it with friends, on their own, in a social setting or at home, at work, before or while driving. Parents know their children best and are therefore in the best position to suggest healthy alternatives to doing drugs. Encouraging children to become involved in sports, clubs, music lessons, community service projects, church, and other after-school activities can have got children and teens active and interested, while building their confidence and interpersonal skills. These activities will also bring youth closer to parents and to other adults and peers who can influence them in convinced(p) ways.

Chemistry 208 All QUIZ Essay Example for Free

Chemistry 208 All QUIZ EssayThe Scientific Method stones throw 1 Performing Experiments Step 2 Making Observations Step 3 Proposing a Hypothesis Step 4 Confirming the Hypothesis Step 5 Proposing a Scientific Law Scientific Notation It is a mathematical expression in which a number is expressed as N x 10n where N contains only one nonzero digit to the left of the decimal and n is an integer. Rules for Determining Significant Figures (digits) -All nonzero digits are significant figures -Counting begins from the left with the prototypic nonzero number -Zeros between nonzero digits are counted as sig. Figures -Terminal zeros (zeros to the right of the right of a number) are always significant if the value contains a decimal point. Ex 2. 3700 g 5 significant figures 17. 50 mL 4 significant figures Rule 1- In calculations involving measured values (with a certain of sig. figs), the number of sig figs in the lowest answer depends on the operation performed. Rule 2- In multiplication and division of measured quantities, the final answer contains the same number of sig figs as are in the measurement with the least number of sig figs.Rule 3- In the final answer of a calculation involving exact numbers, unit conversion factors and constants, the number of significant figures is laid by the measured quantity involved. Density = Mass/ Volume Matter The term matter is used to describe things that occupy space and are apprehensible by our senses. It can be classifies in terms of its physical state or chemical composition. Elements composed of one type of atom. Classified as a metal, nonmetal or metalloid.Compound a combination of elements in a definite proportion. Atoms of each individual elements are chemically combined to form the compound. A chemical change can break down a compound into its individual elements. Mixture a non-pure substance made of 2 or more(prenominal) elements or compounds that can be separated by physical procedures. Protons have a positive c harge, found in the nucleus. Neutrons have no charge, found in the nucleus. Electrons have a negative charge.The atomic number of an element is equal to the number of protons in the nucleus of its atoms. The mass number is equal to the number of protons and neutrons in the atom. To calculate the number of neutrons, subtract the atomic number from the mass number. Molecules are a combination of atoms in a definite proportion e. g. , molecule of piss Ions are charged species formed by loss or gain of electron(s) from an atom. Loss of electron cation (positively charged) Gain of electron anion (negatively charged)

Female Artistic Gymnasts Caloric And Nutrient Intake

Female Artistic Gymnasts Caloric And Nutrient IntakeProper thermic and macro and micro wholesomes inspiration has a signifi nookyt influence in athletic process among distaff aesthetical gymnasts (Applegate, 2001). Appropriate nutrition is an definitive portion of a distaff artistic gymnasts training program because it provides the free goose egg required by the physical structure for optimizing per variateance during practice sessions and competitions (Achten et al., 2004). Following an adequate sustenance during the years gymnasts atomic number 18 engaged in extraneous exercise routines contributes for maintaining a healthy life after their athletic c beers, delaying the effects of aging (Beals, 2002). Also, a oddmentd fodder improves the immune dodge and enhances a persons ability to concentrate (Applegate, 2001).Although appropriate feed is extremely important for athletes, female artistic gymnasts argon a group predominantly predisposed for move in unhealthy take behaviors for weight management purposes (Benson Gillie, 2001). In addition to the typical social pressure placed on females in general to be thin seen in the Western culture, these athletes are part of an environment that focuses on their bodies appearance (Nutter, 2000). Factors such as pressure from coaches, comparison with teammates, performance demands, aesthetics concerns, and physique-revealing uniforms are positively related to an increase in weight control practices in the sport context that female artistic gymnasts are inserted in (Yoon, 2002). Also, different researchers pay the idea that the sport stipulateting may contribute to heighten anxiety related to maintain a perfect form image and promote infective eating behaviors among female gymnasts (Beals, 2002 Soares Ribeiro, 2002).The most(prenominal) common weight control practices observed among female artistic gymnasts are fasting and extremely low calorie ambition (Phillips, 2004). Other methods include self-induced vomiting and the use of diet pills, diuretics, and laxatives (Hassapidou Manstrantoni, 2001). Extremely low elan vital phthisis is associated with delayed puberty, growth problems, and amenorrhea, which has been shown to affect bone development among women (Beals, 2002).In spite of the unquestionable importance of a fit diet in terms of energy requirements and macro and micro nutrients for female artistic gymnasts, various researchers go for demonstrated that there is a substantial neglect of information around sport nutrition among artistic gymnastic coaches and athletes (Ziegler, Jonnalagadda, Lawrence, 2001 Yoon, 2002). According to Beals (2002), it is not rare to pay off gymnasts with erroneous ideas about sport nutrition who engage in extremely low calorie diets in range to lose weight and modify their ashes composition and appearance (p.1934).The interest in analyzing the food ingestion of female artistic gymnasts is attributed to the fact that even w ith evidences proving the importance of correct nutrition for athletic performance, galore(postnominal) gymnasts neglect following a balanced diet. Many times, inappropriate weight control methods are adopted because of the need of information about sports nutrition and/or constant concern about r apieceing a specific torso composition (Applegate, 2001). Therefore, an analysis of the eating habits of female artistic gymnasts should be conducted in grade to determine if their diet contains the proper amounts of calories and macro and micro nutrients.1.1 Statement of the ProblemAppropriate nutrition is a key component on the athletic performance of female artistic gymnasts (Phillips, 2004). However, many athletes tend to adopt short-staffed weight control practices that end up compromising their diet as a root of the constant concern with trunk composition and image (Burke, Gollan, Read, 2001). Therefore, the goal of this paper is to answer the following question On average, do females artistic gymnasts have a proper thermic and macro and micro nutrient intake base on their nutritional needs?CHAPTER IILITERATURE REVIEW2.1 Artistic gymnastic exerciseAccording to the International Federation of Gymnastics, artistic gymnastics, also known as Olympic gymnastics is a sport in which athletes perform a set of exercises in different events. The movements of the gymnasts must be elegant and demonstrate strength, agility, flexibility, coordination, balance and control of the body. The events present in womens artistic gymnastics are vault, uneven bars, balance beams, and floor. In 1881 the International Gymnastics Federation was founded and womens artistic gymnastics entered the Olympics as a team event in 1928. After that, the participation of womens teams in global gymnastics competitions gradually increased.2.2 Body CompositionBody composition measurements are used to describe pad, bone, and muscle percentages in the human body (Berger Shenkin, 2006). It is basically calculated in terms of body fat percentage, which can influence athletic performance during competitions and training sessions (Applegate, 2001). Athletic performance in gymnastic is, to a jumbo extent, dependent on the athletes ability to sustain power (both anaerobically and aerobically) and to overcome resistance. Both of these factors are interrelated with the athletes body composition (Burke et al., 2001).Gymnasts with a grittyer body fat percentage than the desirable may be much prone to injury when performing difficult skills than athletes with a much optimal body composition. Also, excessive body fat can reduce speed and increase the metabolic cost of an action (Nieman et al, 2001). A high magnetic dip body atomic pile, which is the sum of the nonfat part of the human body like muscle, organs, blood and water, may aid athletic performance by improving the strength-to-weight ratio. A higher percentage of lean mass facilitate power production (Jonnalagadd a, Nelson, Lawrence, Bacick, 2002). A low body fat content also functions performance by lowering the resistance because the smaller the body profile, the less resistance the body is likely to produce. For example, a gymnast who weighs 110 pounds (50 kilograms) and is 5 feet (152 centimeters) tall with a body fat percentage of 15 percent lead have a lower air resistance tumbling through the air than a gymnast with the same weight and height but with a body fat percentage of 20 percent (Burke et al., 2001).However, many gymnasts when attempting to achieve an optimal body composition use counterproductive methods (Economos, Bortz, Nelson, 2003). Diets and excessive training often chair in such a severe energy deficit that, although full(a) body mass may be trim, the constituents of weight also change, comm precisely with a lower muscle and a comparatively higher fat percentage (Singh, Evans, Gallagher, Deuster, 2003). The resulting higher body fat and lower muscle mass is asso ciated with performance reducing that motivates the athlete to follow regimens that produce even greater energy deficits, which can place gymnasts at serious health risk (Nutter, 2000).2.3 MacronutrientsThere are two types of essential nutrients, macronutrients and micronutrients. Carbohydrates, proteins, and lipids are the three types of macronutrients (Burke et al., 2001). Macronutrients are the substrates required to maintain the different energy systems responsible for energy production in the body. Each macronutrient produces distinct amounts of energy and ranges a unique role during extraneous physical activity (Baechle Earle, 2008). In general, in a balanced diet 55-75% of the rack up energy comes from carbohydrates, 12-15 % from proteins and 25-30 % from lipids (p.74). A diet should be adjusted to the specific needs of each gymnast. Many aspects should be considered when prescribing a diet to an athlete, such as weight, height, sex, body fat percentage, age, metabolism a nd the type, frequency, intensity, and date of training (Nutter, 2000).2.3.1 CarbohydratesCarbohydrates are the most important source of energy for athletes because they provide adenosine triphosphate (adenosine triphosphate) for muscle contractions (Baechle Earle, 2008). Once ingested, carbohydrates are broken polish into smaller sugars, such as glucose, that are absorbed by the body and utilized as energy (p.76). Glucose molecules that are not immediately needed, get stockd in the muscles and liver in the form of glycogen. Glycogen forms an energy reserve that can be quickly mobilized to meet a sudden need for glucose (Phillips, 2004). In the liver cells, glycogen can constitute up to 8% of the fresh weight (100-120g in an adult) soon after a meal. Only the glycogen stored in the liver can be made accessible to other organs. In the muscle, glycogen is found in a much lower concentration (1% to 2% of the muscle mass), but the total amount exceeds that in the liver (Baerchle E arle, 2008).Since ATP and muscle glycogen are immediately accessible in the muscle, they are the main fuels utilized for short and brilliant bouts of exercise, such as the ones performed by gymnasts (p.90). A short duration and high intensity exercise period is classified as an anaerobic, which utilizes primarily anaerobic pathways for energy production (without oxygen). There are two types of anaerobic energy systems ATP and creatine phosphate (phosphagen) system and anaerobic glycolysis (p.80). Creatine phosphate molecules, which quickly re-synthesize ATP in the muscle cells, are stored in very(prenominal) limited quantities (Ziegler et al., 2001). So, the phosphagen energy system can only provide fuel for the muscle for approximately thirty seconds. After that, energy will be primarily produced by the anaerobic glycolysis process (Singh et al., 2003). Anaerobic glycolysis exclusively uses glucose as a fuel in the absence seizure of oxygen or more specifically, when ATP is neede d at rates that exceed those provided by aerobic metabolism (energy production with oxygen). The result of rapid glucose equipment failure is the formation of lactate (Baerchle Earle, 2008).According to Singh et al (2003), glycogen has four main purposes in the body functioning as a source of energy for muscles, miserliness protein consumption, working as metabolic activator, and providing fuel for the brain (p.329). Muscular glycogen depletion leads to lower levels of blood glucose and liver glycogen (Singh et al., 2003). During prolonged physical activity, insulin secretion from the pancreas decreases, era glucagon and catecholamine concentrations in the blood increase. Catecholamine are hormones (adrenaline, noradrenalide and dopamine) released by the adrenal gland. Together with glucagon they stimulate the break passel of liver glycogen, a process called glycogenolysis (Achten et al, 2004).When glycogen storages reach a very low level, energy is originated from gluconeogenes is, an energy production process in which amino acids, lactate, and glycerol are converted into ATP for muscle contraction (Baechle Earle, 2008). This process becomes an important source of energy during periods of prolonged exercise and low carbohydrate intake. In extreme condition, gluconeogenesis can cause a significant reduction in the lean body mass, which is associated with higher production of nitrogenous wastes (bi-products of protein breakdown) (Jonnalagadda et al., 2002).One way of classifying carbohydrates is based on the glycemic index (GI), which is a measure of the effect of a carbohydrate privileged food on blood glucose levels relative to glucose. Carbohydrates that break down quickly during digestion, releasing glucose rapidly into the bloodstream, have a high GI carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream, have a low GI (Singh et al, 2003). A lower glycemic response is associated to a smaller insulin demand. G lucose and white scraping are used as reference foods and have a glycemic index of 100. The glycemic index is determined by measuring the postprandial glycemia (glucose levels after a meal) for a time interval of two hours after the ingestion of 50g of a specific food (Berger Shenkin). A glucose response curve is plotted depicting the relationship among blood glucose elevation and time. The area of the curve above the fasting level is measured and divided by the area of the curve of the standard food (either glucose or white bread) and multiplied by 100 (Jonnalagadda, 2002).Up to two hours prior exercise, a meal that is rich in carbohydrates of low (milk and vegetables) or moderate GI (fruits) is preferred instead of one with a high GI. Foods with low to moderate GI will maintain the energy level balanced and avoid energy peaks by keeping the blood glucose and insulin levels low (Burke et al., 2001). In addition, these foods tend to be lower in fat and contain more vitamins, mine rals and fiber than the ones with a high GI. Also, low to moderate IG foods promote glycogen storages, which will then improve performance during competition or practice session (Benson Gillie, 2001).Carbohydrate intake after physical activity is extremely important because it will replenish glycogen storages used during exercise (Burke et al, 2001). Also, after physical activity cells become more sensitivity to insulin, increasing glucose uptake by the tissues. After physical activity, muscle and liver glycogen is completely replenished in 24 hours. Therefore, adequate carbohydrate intake is extremely important for athletes (Nutter, 2000). According to Economos et al. (2003), 50 to 55% of the total thermal intake should come from carbohydrates. Other authors believe that the carbohydrate percentage in the diet of artistic gymnasts should vary from 55 to 75% of the total calories (p. 388). The American Dietetic Association (ADA) recommends a daily intake of 150 to 175 grams of c arbohydrate for each 1000 calories consumed (Yoon ,2002). Lastly, the American College of Sports Medicine (ACSM) suggests that more than 55% of the total calories should be in the form of carbohydrates (Beals, 2002).2.3.2 ProteinsProteins are composed of one or more amino acids. A typical protein contains 200-300 amino acids but some are much smaller (the smallest are often called peptides) (Beals, 2002). More than 300 different types of amino acids are found in nature but only 20 exist in the human body. Among these 20 amino acids, eight are essential, which means that they cannot be synthesized by the body. The others are called non-essential amino acids, since they are produced by the organism (Phillips, 2004).When the body does not have enough carbohydrate, protein is broken down to produce glucose for energy (Baerchle Earle, 2008). suitable carbohydrate intake helps prevent protein from being used as energy. Because the primary role of protein is to function as the building b locks for muscles, bone, skin, hair, and other tissues, relying on protein for energy (by failing to take in adequate carbohydrate) can limit the athletes ability to build and maintain tissues. Additionally, utilizing protein as an energy source stresses the kidneys because they have to work harder to eliminate the byproducts of protein breakdown (Soares Ribeiro, 2002).In the body, proteins play other important roles such as functioning as hormones, enzymes and neurotransmitters, participating in the process of energy production, and correct several metabolic pathways important during physical activity. Amino acids also have a small participation in energy production during extenuating physical activities (Economos et al., 2003). Whereas carbohydrates provide more than 80% of the fuel utilized in the metabolic pathways, amino acids contribute for only 5 to 10% in physical activities of long duration (Jonnalagadda et al., 2002). The recommended protein intake for gymnasts is aroun d 1.1 grams/kg of body weight or 12 to 15% of the total caloric intake (Burke et al., 2001).2.3.3 LipidsThe main lipids in the human body are triglycerides, phospholipids, steroids, and lipoproteins. Triglycerides, which are composed by one glycerol molecule and three molecules of productive acids, are the most common lipids in the diet and are stored by the body (Nieman, 2001).During a prolonged exercise period, such as a long gymnastic practice, stored triglycerides in the adipose tissue are broken down into fatty acids and glycerol by the enzyme lipase (Economos, 2003). Adrenaline and glucagon secreted in response to low levels of blood glucose stimulate the release of triglycerides from the adipose tissue. High levels of insulin and blood glucose have the gelid effect, since it is associated with the deposit of triglycerides in the adipose tissue (Singh et al, 2003). Glycerol is phosphorylated in the liver into glucose-6-fosfate, resulting in substrate for the formation of glu cose (glyconeogenesis) (Baerchle Earle, 2008). The American Dietetic Association (ADA) recommends that 30% of the total caloric intake should come from lipids. The American College of Sports Medicine (ACSM) suggests a lipid intake of 25-30% of the total caloric intake.2.4 MicronutrientsVitamins and minerals play an important role in regulating energetic pathways, contracting and building muscles, functioning as antioxidants, and participating in the immunologic system (Economos, 2003).2.4.1 MineralsMinerals represent 4% of total body weight. The two most important minerals in the diet of athletes are iron and calcium because the body concentrations of these are more likely to be affected by intense training periods. Also, they play significant roles in athletic performance (Singh et al., 2003).Calcium plays an important role in muscle contraction. It is stored in the sarcoplasmatic reticulum of muscles and released when muscles fibers are stimulated, forming actine-miosine bridges and causing the muscle to contract (Yoon, 2002). Besides, according to Phillips (2004), there is a correlation between a poor diet in calcium and the occurrence of stress fractures. gloomy calcium levels in the diet of female athletes are also related to the incidence of earlier osteoporosis than in the average women after menopause (Nutter, 2000). Athletes should have a daily intake of calcium equal to 1.2 grams (Achten et al., 2004).Besides calcium, iron is also significant in the diet of athletes. Since iron is found in the hemoglobin and myoglobin, lack of this mineral directly affects oxygen transport in the blood and to muscles (Beals, 2002). Iron deficits in the body can cause anemia, condition in which hemoglobin is reduced in the blood and red blood cells become small and pale (Berger Shenkin, 2006). Common symptoms associated with iron-deficiency anemia are slow recover after physical activity, irritability, tiredness, depression, insomnia, and consequently a decrease in athletic performance (Beals, 2002). For female athletes the recommended dietary intake of iron is 18mg/day (Baerchle Earle, 2008).2.4.2 VitaminsVitamins A, D, E, and K are denominated lipossoluble and vitamins B1 (thiamin), B2 (riboflavin), niacin (B3), pyridoxine (B6), antipernicious anemia factor (B12), pantotenic acid, and vitamin C are called hydrosoluble (Willmore Costill, 2001). Vitamins from the B complex function as co-factors and coenzymes in reactions related to the energetic metabolism, such as glycosis, tricarboxylic acid cycle, and beta oxidation of fatty acids (Singh et al., 2003).Vitamin C is important for iron absorption and plays an important role in the synthesis of collagen, carnitine, epinephrine, and serotonin (Yoon, 2002). Vitamin C, E, and beta-carotene (precursor of vitamin A) function as antioxidant, protecting the organism against infections and preventing any ill-treat that free radicals (toxic substances released during physical activity) may cause t o tendons and ligaments (Nutter, 2000). Therefore, a proper intake of beta-carotene and vitamin C and E are important in the diet of athletes, since they will help in the elimination of free radicals. Lack of vitamin C may cause muscular weakness, decrease lipid breakdown, and increase occurrence of injuries (Applegate, 2001). Restrictions in energy and nutrient intake in the diet of gymnasts may cause lack of vitamins in the body (Mullinix, Jonnalagadda, Rosenbloom, Thompson, Kicklighter, 2003).2.5 Caloric IntakeEnergetic expenditure is determined by the thermal effects of food (5-10%), basal metabolic rate (60-65%) and intensity, duration, and frequency of physical activity (25-35%). The thermic effect of food is the energy required to process and store nutrients for use. The basal metabolic rate (BMR) is the amount of energy spent by the body at rest to maintain in the vital organs functioning. A low body fat percentage and a high muscle mass increase BMR (Baerchle Earle, 2008 ).Female artistic gymnasts should have a caloric intake adequated to their energy expenditure in order to maximize proper performance, body composition, and health (Phillips, 2004). A low energy intake or an inadequate diet in terms of macro and micro nutrients may result in improper intake of important nutrients for the energetic metabolism and muscle tissue regeneration (Ziegler et al., 2001). Female artistic gymnasts usually practice for long periods (5 to 6 hours a day), which results in high energy expenditure, so they should have a caloric intake of 40-45 kilocalories/kilogram of body weight (Economos et al., 2003).Excessive concern with body image and weight control may affect caloric intake among female artistic gymnasts (Ziegler et al., 2001). Inadequate energetic consumption and eating disorders are frequently seen among athletes who participate in sports in which performance is associate to low body weight, such as ice skating and gymnastics (Ziegler et al, 2001 Yoon, 200 2). Soares Ribeiro (2002) reported that 75% of gymnasts who have been told to be overweight from their coaches adopted strong measures in order to loose weight. Therefore, coaches play important roles in avoiding extreme weight control measures and consequently excessive low calorie diets among gymnasts. Also, female artistic gymnasts should consult with sports dietitian in order to minimize this type of problem (Hassapidou Manstrantoni, 2001).2.6 Eating BehaviorBenson and Gillie (2001) evaluated the eating habits of 32 female artistic gymnasts (20 to 24 years old) from six different gymnastics schools in Canada based on their food intake of three distinct days in which they had normal practice schedules. The average caloric intake (1,838 calories (kcal)/day) was relatively low compared with the energetic recommendation for female artistic gymnasts. Besides, 40% of the athletes had diets that were low in calcium, folic acid, vitamin E, and pyridoxine and 53% showed a low iron inta ke. On average, the diet of athletes was constitued of 15% of proteins, 36% of lipids, and 49% of carbohydrates (p.83).Mullinix et al. (2003) analyzed the dietary intake of 13 members of two different collegiate womens artistic gymnastic teams (19 to 25 years old) based on the dietary intake of six days collected during 2 weeks. The average caloric intake was equal to 1,845kcal/day and athletes presented a lower caloric intake inferior to the recommendation, like the previous study. Fifty-five percent of athletes consumed less than 50% of the recommended intake for pyridoxine, folic acid, calcium, and iron (p.590).Yoon (2002) also studied the eating habits of ten collegiate athletes using the food intake and activity level of three days. It was estimated on average the daily energy expenditure was 2,855kcal/day. However, the caloric intake was, on average, only 1,357kcal/day, representing a deficit of 1,498 calories per day. More than 50% of the gymnasts had a low intake of calcium , iron, and vitamin A (p.1553)In a study conducted by Ziegler et al. (2001), twenty American gymnasts (22 years old on average) recorded their food intake during three days in which they had training. After analysis, it was possible to conclude that, on average, there was a lack of vitamins A, D, folic acid, calcium, magnesium, phosphorus, and zinc. One fourth of the athletes were taking vitamin supplements. The average caloric intake was equal to 1,771kcal/day (56g of proteins, 75g of lipids, and 218g of carbohydrates) (p.106).In a study conducted by Soares and Ribeiro (2002), the food intake of 20 Brazilian gymasts was evaluated (18-20 years old). In order to analyze the eating behavior of athletes, the authors recorded their food intake for three days and asked participants to do a 24 hour food recall. The average caloric intake was equal to 1,521kcal/day. The carbohydrate content in their diet ranged from 50% to 58% and the protein intake from 15% to 19%. On average, there was a deficit of calcium (45% below the recommendation), magnesium, iron, and zinc (p.350).Hassapidou Manstrantoni (2001) compared chances in the diet of 25 Greek female artistic gymnastics between competitive and non-competitive stages of training. Authors reported that there was no variation in the diet among these two different periods. In both stages, there was a negative energy balance in the diet of 68% of athletes, which was below the recommended caloric intake for gymnasts. Protein intake and micronutrient intakes were, on average, within the recommendation for athletes. Adequate micronutrient intake was attributed to the high consumption of vegetables and fruits, which is a characteristic of the Mediterranean diet (p.395).3. CONCLUSIONIn order to achieve a good performance, female artistic gymnasts should adopt a balanced and adequate diet. Athletes should have a varied diet that provides them with proper caloric and macro and micronutrients intake. Factors, such as pressure fr om coaches to keep a perfect body composition lead many gymnasts to adopt inappropriate weight control methods. In the last decade, eating behavior of gymnasts has caught the attention of many researchers in the sphere of sports nutrition and exercise science. Recent studies have indicated a constant anxiety related to weight control among many gymnasts, which frequently results in inappropriate eating habits and extremely low calorie diets compared to the recommendations.The studies presented showed that, on average, gymnasts follow low calorie diets, which are below the recommended caloric intake and do not provide athletes with the proper amounts of macronutrients. Besides, also according to the studies there appears to be a low mineral and vitamin intake in the athletes diet. As a result, performance is very likely to be compromised since appropriate nutrition is essential for optimal functioning of the body and health. The only exception was the study conducted by Hassapidou M anstrantoni (2001), in which Greek gymnasts had an adequate intake of micronutrients. This can be attributed to the fact that athletes were probably eating according to the Mediterranean diet, which is rich in fruits and vegetables.In conclusion, the analysis of the studies showed that, on average, the eating behavior of female artistic gymnasts does not follow the nutritional recommendations and adequate intake of calories and macro and micro nutrients. For future studies, in order to improve their eating behavior and mindset about body image, the food intake of athletes should be evaluated after exposure to psychological counseling and nutritional reeducation for a reasonable period of time.

Measuring weak-form market efficiency

Measuring weak-form trade qualificationMeasuring Weak-form Market EfficiencyABSTRACTThis paper analyses weak-form efficiency in the U.S. securities industry. twain(prenominal) day by day and monthly turn ins be employed for auto correlation analysis, difference ratio tests and stand up tests. Three conclusions atomic number 18 reached. Firstly, aegis returns ar predictable to some extent. sequence individualistic deport returns atomic number 18 decrepit negatively correlated and difficult to predict, merchandise-wide indices with outstanding recent performance delegate a positive autocorrelation and offer more(prenominal) predictable profit opportunities. Secondly, monthly returns pursue ergodic locomote better than passing(a) returns and ar thence more weak-form efficient. Fin on the wholey, weak-form inefficiency is non necessarily bad. Investors should be rewarded a certain degree of predictability for bearing risks. competent foodstuff hypothesis (E MH), also known as information efficiency, refers to the extent to which stock prices incorporate altogether available information. The notion is important in service investors to understand credential behaviour so as to make wise investment decisions. According to Fama (1970), there atomic number 18 three versions of market efficiency the weak, semi upstanding, and strong form. They differ with respect to the information that is incorporated in the stock prices. The weak form efficiency assumes that stock prices already incorporate either past handicraft information. Therefore, technical analysis on past stock prices will not be helpful in gaining abnormal returns. The semistrong form efficiency extends the information go by to all publicly available information including not solo past trading information scarcely also fundamental selective information on sign prospects. Therefore, neither technical analysis nor fundamental analysis will be able to produce abnormal retu rns. Strong form efficiency differs from the above deuce in stating that stock prices not only reflect publicly available information but also private inside information. However, this form of market efficiency is always rejected by empirical evidence.If weak-form efficiency holds true, the information contained in past stock price will be completely and instantly reflected in the current price. Under such condition, no pattern abide be observed in stock prices. In new(prenominal) words, stock prices tend to get a random walk model. Therefore, the test of weak-form market efficiency is actually a test of random walk but not vice versa. The more efficient the market is, the more random are the stock prices, and efforts by fund managers to exploit past price history will not be profitable since incoming prices are completely unpredictable. Therefore, metre weak-form efficiency is crucial not only in academic research but also in practice because it affects trading strategies.This paper primarily tests the weak-form efficiency for three stocks-Faro Technologies Inc. (FARO), FEI Company (FEIC) and Fidelity Southern Corporation (LION) and devil decile indices-the big board/AMEX/NASDAQ Index capitalization based Deciles 1 and 10 ( granny D1 and gran D10). Both quotidian and monthly data are employed here to detect any violation of the random walk hypothesis.The remainder of the paper is structured in the attach toing way. Section I provides a brief introduction of the three firms and two decile indices. Section II describes the data and discusses the methodology used. Section III innovates descriptive statistics. Section IV is the resolvent based on empirical analysis. Finally, section V concludes the paper.I. The Companies1A. Faro Technologies Inc (FARO)FARO Technologies is an instrument familiarity whose principle activities include design and develop portable 3-D electronic systems for industrial applications in the manufacturing system. The companys principal products include the Faro Arm, Faro Scan Arm and Faro Gage provide measuring devices. It mainly operates in the United States and Europe.B. FEI Company (FEI)FEI is a leading scientific instruments company which develops and manufactures diversified semiconductor equipments including electron microscopes and beam systems. It operates in quadruple segments NanoElectronics, NanoResearch and Industry, NanoBiology and Service and Components. With a 60-year history, it now has approximately 1800 employees and sells products to more than 50 countries around the world.C. Fidelity Southern Corp. (LION)Fidelity Southern Corp. is one of the largest community banks in vacuum tube Atlanta which provides a wide range of financial services including commercial and mortgage services to both corporate and personal customers. It also provides international dispense services, trust services, credit card loans, and merchant services. The company provides financial products and services f or business and retail customers primarily through branches and via internet.D. NYSE/AMEX/NASDAQ IndexIt is an proponent taken from the Center for Research in Security Prices (CRSP) which includes all common stocks listed on the NYSE, Amex, and NASDAQ National Market. The index is constructed by ranking all NYSE companies accord to their market capitalization in the first place. They are then divided into 10 decile portfolios. Amex and NASDAQ stocks are then placed into the deciles based on NYSE breakpoints. The smallest and the largest firms based on market capitalization are placed into Decile 1 and Decile 10, respectively.II. Data and MethodologyA. DataData for the three stocks and two decile indices in our interpret are all obtained from the Center for Research in Securities Prices database (CRSP) on both daily and monthly hind end from January 2000 to December 2005. Returns are then computed on both basis, generating a total of 1507 daily observations and 71 monthly observ ations. The NYSE/AMEX/NASDAQ Index is CRSP Capitalisation-based so that Decile 1 and 10 represent the smallest and largest firms, respectively, based on market capitalisation. In addition, The Standard and Poors calciferol Index (SP 500) is used as a proxy for the market index. It is a encouraged-weighted index which incorporates the largest 500 stocks in US market. For similitude purposes, both continuously compounded (log) returns and simple returns are inform, although the analysis is based on the result of the first one.B. MethodsB.1. Autocorrelation TestsOne of the most intuitive and simple tests of random walk is to test for serial colony, i.e. autocorrelation. The autocorrelation is a clipping-series phenomenon, which implies the serial correlation between certain resortged prys in a time series. The first-order autocorrelation, for instance, indicates to what extent neighboring observations are correlated. The autocorrelation test is always used to test RW3, which is a less restrictive version of random walk model, allowing the existence of dependent but uncorrelated increments in return data. The formula of autocorrelation at lag k is given by(1) where is the autocorrelation at lag is the log-return on stock at time and is the log-return on stock at time. A greater than zero indicates a positive serial correlation whereas a less than zero indicates a negative serial correlation. Both positive and negative autocorrelation represent departures from the random walk model. If is earthshakingly different from zero, the secret code hypothesis of a random walk is rejected.The autocorrelation coefficients up to 5 lags for daily data and 3 lags for monthly data are reported in our test. Results of the Ljung-Box test for all lags up to the above mentioned for both daily and monthly data are also reported. The Ljung-Box test is a more goodly test by summing the form autocorrelations. It provides evidence for whether departure for zero autocorrelatio n is observed at all lags up to certain lags in either direction. The Q-statistic up to a certain lag m is given by(2)B.2. Variance symmetry TestsWe deliver the goods Lo and MacKinlays (1988) sensation variance ratio (VR) test in our study. The test is based on a very important assumption of random walk that variance of increments is a linear function of the time interval. In other words, if the random walk holds, the variance of the qth differed value should be equal to q times the variance of the first differed value. For example, the variance of a two-period return should be equal to twice the variance of the one-period return. According to its definition, the formula of variance ratio is denoted by(3) where q is any positive integer. Under the unreal hypothesis of a random walk, VR(q) should be equal to one at all lags. If VR(q) is greater than one, there is positive serial correlation which indicates a industry in prices, corresponding to the momentum effect. If VR(q) is l ess than one, there is negative serial correlation which indicates a reversal in prices, corresponding to the toy with-reverting process.Note that the above two test are also tests of how stock prices react to publicly available information in the past. If market efficiency holds true, information from past prices should be straightaway and fully reflected in the current stock price. Therefore, future stock price change conditioned on past prices should be equal to zero.B.3. Griffin-Kelly-Nardari endure TestsAs defined by Griffin, Kelly and Nardari (2007), clutches is a measure of sensitivity of current returns to past market-wide information.2 Speaking differently, delay measures how quickly stock returns can react to market returns. The logic behind this is that a stock which is slow to incorporate market information is less efficient than a stock which responds quickly to market movements.SP 500 index is employed in delay test to examine the sensitivity of stock returns to ma rket information. For each stock and decile index, both restricted and unrestricted models are estimated from January 2000 to December 2005. The unrestricted model is given by(4) where is the log-return on stock i at time t is the market log-return (return for SP 500 index) at time t is the lagged market return is the coefficient on the lagged market return and is the lag which is 1, 2, 3, 4 for the daily data and 1, 2, 3 for the monthly data. The restricted model is as follows which sets all to be zero(5) Delay is then calculated based on adjusted R-squares from above regressions as follows(6) An alternative scaled measure of delay is given by(7) Both measures are reported in a way that the larger the calculated delay value, the more return variation is explained by lagged market returns and thus the more delayed response to the market information.III. Descriptive StatisticsA. Daily frequencies table I shows the summary statistic of daily returns for the three stocks and two decile indices. The highest slopped return is for FARO (0.0012), whereas the lowest mean return is for naan D10 (0.0000). In terms of median return, grannie D1 (0.0015) outperforms all the other stocks. Both the highest maximum return and the lowest minimum return (0.2998 and -0.2184, respectively) are for FARO, corresponding to its highest standard deviance (0.0485) among all, indicating that FARO is the most volatile in returns. On the other hand, both the lowest maximum return and highest minimum return (0.0543 and -0.0675, respectively) are for nan D10. However granny D10 is only the second least volatile, part the lowest standard deviation is for granny knot D1 (0.0108). blueprint 1 and 2 presents the price direct of the most and least volatile index (stock). All the above observations remain true if we change from log-return basis to a simple return basis.In terms of the degree of asymmetry of the return distributions, all stocks and indices are positively skewed, with the only exception of NAN D1. The positive lopsidedness implies that more extreme values are in the right tail of the distribution, i.e. stocks are more likely to have times when performance is extremely good. On the other hand, NAN D1 is slightly negatively skewed, which means that returns are more likely to be lower that what is expected by normal distribution. In measuring the peakedness of return distributions, positive excess kurtosis is observed in all stocks and indices, also known as a leptokurtic distribution, which means that returns either cluster around the mean or disperse in the two ends of the distribution. All the above observations can be used to conclusively reject the zippo hypothesis that daily returns are normally distributed. What more, results from Jarque-Bera test provide supportive evidence for rejection of the normality hypothesis at all significant levels for all stocks and indices.B. Monthly frequenciesDescriptive statistics of monthly returns are likewise presented in mesa II. Most of the above conclusions reached for daily returns are also valid in the context of monthly returns. In other words, what is the highest (lowest) value for daily returns is also the highest (lowest) for monthly returns in most cases. The only exceptions are for the highest value in median returns and the lowest value and standard deviation in minimum returns. In this situation, NAN D10 (0.0460) and FARO (0.1944) have the least and most dispersion according to their standard deviations, compared with NAN D1 and FARO in daily case. From above observation, we can describe that decile indices are more stable than individual stocks in terms of returns. Whats more, monthly returns have larger magnitude in most values than daily returns. culmination to the measurement of asymmetry and peakedness of return distributions, only NAN D10 (-0.4531) is negatively skewed. However, the degree of skewness is not far from 0. Other stocks and index are all positively skewed with both FEIC (0.0395) and LION (0.0320) having a skewness value very close to 0. Almost all stocks and index have a degree of kurtosis like to that of normal distribution, except that NAN D1 (8.6623) is highly peaked. This is also consistent with the results of JB p-values, based on which we conclude that FEIC, LION and NAN D10 are approximately normal because we stop to reject the hypothesis that they are normally distributed at 5% or higher levels (see Figure 3 and 4 for reference). However when simple return basis is used, FEIC is no longer normally distributed even at the 1% significant level. Except this, using simple return produces similar results.IV. ResultsA. Autocorrelation TestsA.1. Tests for Log-ReturnsThe results of autocorrelation tests for up to 5 lags of daily log-returns and up to 3 lags of monthly log-returns for three stocks and two decile indices from January 2000 to December 2005 are summarised in Table III. Both the autocorrelation (AC) and partial autocor relation (PAC) are examined in our tests.As is shown in Panel A, all 5 lags of FARO, FEIC and NAN D10 for both AC and PAC are insignificant at 5% level, except for the fourth-order PAC coefficient of FARO (-0.052), which is slightly negatively significant. On the contrary, NAN D1 has significant positive AC and PAC at almost all lags except in the fourth order, its PAC (0.050) is barely in spite of appearance the 5% significance level. The significant AC and PAC coefficients reject the null hypothesis of no serial correlation in NAN D1, thereby rejecting the weak-form efficiency. In terms of LION, significant negative autocorrelation coefficients are only observed in the first two orders and its higher-order coefficients are not statistically significant. Besides that, we find that all the stocks and indices have negative autocorrelation coefficients at most of their lags, with the only exception of NAN D1, whose coefficients are all positive. The strictly positive AC and PAC indic ates persistence in returns, i.e. a momentum effect for NAN D1, which means that good or bad performances in the past tend to continue over time.We also present the Ljung-Box (L-B) test statistic in order to see whether autocorrelation coefficients up to a specific lag are jointly significant. Since RW1 implies all autocorrelations are zero, the L-B test is more powerful because it tests the joint hypothesis. As is shown in the table, both LION and NAN D1 have significant Q values in all lags at all levels, while no(prenominal) of FARO, FEIC and NAN D10 has significant Q values.Based on above daily observations, we may conclude that the null hypothesis of no serial correlation is rejected at all levels for LION and NAN D1, but the null hypothesis cannot be rejected at either 5% level or 10% level for FARO, FEIC and NAN D10. This means that both LION and NAN D1 are weak-form inefficient. By looking at their past performance, we find that while NAN D1 outperformed the market in sampl e period, LION performed badly in the same period. Therefore, it seems that stocks or indices with best and worst recent performance have stronger autocorrelation. In particular, LION shows a positive autocorrelation in returns, suggesting that market-wide indices with outstanding recent performance have momentum in returns over short periods, which offer predictable opportunities to investors.When monthly returns are employed, no case-by-case stock or index has significant AC or PAC in any lag reported at 5% level. It is in logical argument with daily returns, which means that monthly returns follow a random walk better than daily returns. More powerful L-B test confirms our conclusion by present that Q statistics for all stocks and indices are statistically insignificant at either 5% or 10% level. Therefore, the L-B null hypothesis can be conclusively rejected for all stocks and indices up to 3 lags. When compared with daily returns, monthly returns seem to follow random walk b etter and are thus more weak-form efficient.A.2. Tests for Squared Log-Returns notwithstanding when returns are not correlated, their volatility may be correlated. Therefore, it is necessary for us to expand the study from returns to variances of returns. Squared log-returns and domineering value of log-returns are measures of variances and are thus useful in studying the serial dependence of return volatility. The results of autocorrelation analysis for daily squared log-returns for all three stocks and two decile indices are likewise reported in Table IV.In contrast to the results for log-returns, coefficients for FEIC, LION, NAN D1 and NAN D10 are significantly different from zero, except for the forth-order PAC coefficient (0.025) for FEIC, the fifth-order PAC coefficient for LION (-0.047) and third- and forth-order PAC coefficient for NAN D1 (-0.020 and -0.014, respectively). FARO has significant positive AC and PAC at the first lag and a significant AC at the third lag. The L -B test provides stronger evidence against the null hypothesis that sum of the squared autocorrelations up to 5 lags is zero for all stocks and indices at all significant levels, based on which we confirm our result that squared log-returns do not follow a random walk. Another contrasting result with that of log-returns is that almost all the autocorrelation coefficients are positive, indicating a stronger positive serial dependence in squared log-returns.In terms of monthly data, only FEIC and NAN D10 have significant positive third-order AC and PAC estimates. Other stocks and indices have coefficients not significantly different from zero. The result is supported by Ljung-Box test statistics show that Q values are only statistically significant in the third lag for both FEIC and NAN D10. This is consistent with the result reached for log-returns above, which says that monthly returns appear to be more random than daily returns.A.3. Tests for the Absolute Values of Log-ReturnsTabl e V provides autocorrelation results for the controlling value of log-returns in similar manner. However, as will be discussed below, the results are even more contrasting than that in Table IV.In Panel A, all the stocks and indices have significant positive serial correlation while insignificant PAC estimates are only displayed in lag 5 for both FARO and LION. living above result, Q values provide evidence against the null hypothesis of no autocorrelation. Therefore, absolute value of daily log-returns exhibit stronger serial dependence than in Table III and IV, and autocorrelations are strictly positive for all stocks and indices. Coming to the absolute value of monthly log-returns, only FEIC displays significant individual and joint serial correlation. NAN D1 also displays a significant Q value in lag 2 at 5% level, but it is insignificant at 1% level.Based on the above evidence, two consistent conclusions can be made at this point. First of all, by changing ingredients in our test from log-returns to squared log-returns and absolute value of log-returns, more positive serial correlation can be observed, especially in daily data. Therefore, return variances are more correlated. Secondly, monthly returns tend to follow a random walk model better than daily returns.A.4. Correlation Matrix of Stocks and IndicesTable VI presents the correlation matrix for all stocks and indices. As is shown in Panel A for daily result, all of the correlations are positive, ranging from 0.0551 (LION-FARO) to 0.5299 (NAN D10-FEIC). Within individual stocks, correlation coefficients do not differ a lot. The highest correlation is between FEIC and FARO with only 0.1214, indicating a fairly weak relationship between individual stocks returns. However, in terms of stock-index relationships, they differ drastically from 0.0638 (NAN D10-FARO) to 0.5299 (NAN D10-FEIC). While the positive correlation implies that the three stocks follow the indices in the same direction, the extent to which they will move with the indices is quite different, indicating different levels of risk with regard to different stock. Finally, we find that the correlation between NAN D10 and NAN D1 is the second highest at 0.5052.Panel B provides the correlation matrix for monthly data. Similar to results for daily data, negative correlation is not observed. The highest correlation attributes to that between NAN D10 and FEIC (0.7109) one time again, but the lowest is between LION and FEIC (0.1146) this time. Compared with results in Panel A, correlation within individual stocks is slightly higher on average. The improvement in correlation is even more obvious between stocks and indices. It implies that stock prices can change dramatically from day to day, but they tend to follow the movement of indices in a longer horizon. Finally, the correlation between two indices is once again the second highest at 0.5116, following that between NAN D10 and FEIC. It is also comprise that the correlat ion between indices improves only marginally when daily data are replaced by monthly data, indicating a relatively stable relationship between indices.B. Variance Ratio TestsThe results of variance ratio tests are presented in Table VII for each of the three stocks and two decile indices. The test is designed to test for the null hypothesis of a random walk under both homoskedasticity and heteroskedasticity. Since the violation of a random walk can result either from changing variance, i.e. heteroskedasticity, or autocorrelation in returns, the test can help to discriminate reasons for deviation to some extent. The lag orders are 2, 4, 8 and 16. In Table VII, the variance ratio (VR(q)), the homoskedastic-consistent statistics (Z(q)) and the heteroskedastic-consistent statistics (Z*(q)) are presented for each lag.As is pointed out by Lo and MacKinlay (1988), the variance ratio statistic VR(2) is equal to one plus the first-order correlation coefficient. Since all the autocorrelations are zero under RW1, VR(2) should equal one. The conclusion can be generalised further to state that for all q, VR(q) should equal one.According to the first Panel in Table VII, of all stocks and indices, only LION and NAN D1 have variance ratios that are significantly different from one at all lags. Therefore, the null hypothesis of a random walk under both homoskedasticity and heteroskedasticity is rejected for LION and NAN D1, and thus they are not weak-form efficient because of autocorrelations. In terms of FARO, the null hypothesis of a homoskedastic random walk is rejected, while the hypothesis of a heteroskedastic random walk is not. This implies that the rejection of random walk under homoskedasticity could partly result from, if not entirely due to heteroskedasticity. On the other hand, both FEIC and NAN D10 follow random walk and turn out to be efficient in weak form, corresponding exactly to the autocorrelation results reached before in Table III.Panel B shows that when m onthly data are used, the null hypothesis under both forms of random walk can only be rejected for FARO. As for FEIC, the random walk null hypothesis is rejected under homoskedasticity, but not under heteroskedasticity, indicating that rejection is not due to changing variances because Z*(q) is heteroskedasticity-consistent.As is shown in Panel A for daily data, all individual stocks have variance ratios less than one, implying negative autocorrelation. However, the autocorrelation for stocks is statistically insignificant except for LION. On the other hand, variance ratios for NAN D1 are greater than one and increasing in q. The above finding provides supplementary evidence to the results of autocorrelation tests. As Table III shows, NAN D1 has positive autocorrelation coefficients in all lags, suggesting a momentum effect in multiperiod returns. Both findings appear to be well supported by empirical evidence. While daily returns of individual stocks seem to be frail negatively co rrelated (French and Roll (1986)), returns for best performing market indices such as NAN D1 show strong positive autocorrelation (Campbell, Lo, and MacKinlay (1997)). The fact that individual stocks have statistically insignificant autocorrelations is mainly due to the specific noise contained in company information, which makes individual security returns unpredictable. On the contrary, while the positive serial correlation for NAN D1 violates the random walk, such deviation provides investors with confidence to forecast future prices and reliability to make profits.C. Griffin, Kelly and Nardari DELAY TestsThe results of delay test for the three stocks and two decile indices over the January 2000 to December 2005 period are summarised in Table VIII. We use lag 1, 2, 3, 4 for the daily data and 1, 2, 3 for the monthly data.As is presented in Panel A for daily returns, Delay_1 value for NAN D10 is close to zero and hence not significant, while NAN D1 has the highest delay among all stocks and indices. The rank of delay within individual stocks seems to have a positive relationship between size of it and delay value, by showing that delay of LION, the stock with smallest market capitalization is lowest, while the delay of FEIC, the stock with largest market capitalization is highest. It seems to contradict with the Griffin, Kelly and Nardari (2006) study, which says that there is an inverse relationship between size and delay. One possible explanation for that is that delay calculated by daily data on individual firms is noisy.The scaled measure Delay_2 produces consistent conclusion but with higher magnitude in values. Delay_2 values are very different from zero for FARO, FEIC, LION and NAN D1. The largest increase in value is seen in FARO from 0.0067 for Delay_1 to 0.7901 for Delay_2. Therefore, Griffin, Kelly and Nardari delay measure is preferable, because the scaled version can result in large values without economic significance.As is displayed in Panel B, employing monthly data also leads to higher Delay_1 values, indicating that more variation of monthly returns are captured by lagged market returns and hence monthly returns are not as sensitive as daily returns to market-wide news. However, an inverse relationship is found this time between delay and market value of individual stocks. Therefore, monthly data provides consistent result to support Griffin, Kelly and Nardari (2006) result as one would normally expect larger stocks to be more efficient in responding to market. Similar to the result for daily data, scaled measure once again produces higher values than its alternative but it provides the same results.V. ConclusionThe main objective of this paper is to test weak-form efficiency in the U.S. market. As is found by selected tests, NAN D10 and FEIC provide the most consistent evidence to show weak-form efficiency, while the deviation from random walk is suggested for other stocks and indices, especially for NAN D1 and LION . It indicates that security returns are predictable to some degree, especially for those having best and worst recent performance.The three autocorrelation tests provide different results in terms of daily returns. While the null hypothesis of random walk is rejected for NAN D1 and LION based on log-returns, it is rejected for all stocks and indices based on both squared and absolute value of log-returns, indicating that return variances are more correlated. On the other hand, results in the context of monthly returns are consistent. Monthly returns follow a random walk much better than daily returns in all three tests. Most evidently, the autocorrelation test fails to reject the presence of random walk for all stocks and indices when monthly log-returns are employed.The variance ratio tests provide supportive evidence for autocorrelation tests. Both tests find that in terms of daily return, NAN D1 and LION show a significant return dependence. In particular, variance ratios for NA N D1 are all above one, corresponding to its positive AC and PAC coefficients, thus implying positive autocorrelation in returns. Whats more, individual stocks have variance ratios less than one with FEIC and FARO both being insignificant. The above evidence conclusively suggest that while individual stock returns are weakly negatively related and difficult to predict, market-wide indices with outstanding recent performance such as NAN D1 tend to show a stronger positive serial correlation and thus offer predictable profit opportunities.The evidence regarding delay tests is consistent with earlier findings to a large extent. NAN D1 has highest delay in both daily and monthly cases, implying an inefficient response to market news. In the context of monthly log-returns, delay values for individual stocks rank inversely based on market capitalisation with larger cap stocks having lower delay, suggesting that small stocks do not capture past public information quickly and are thus ineff icient.Finally, deviation from a random walk model and thus being weak-form inefficiency is not necessarily bad. In fact, investors should be rewarded a certain degree of predictability for bearing risks. Therefore, future research could be done by incorporating risk into the model.1 Company information is mainly obtained from Thomson One Banker database.2 Griffin, John M., Patrick J. Kelly, and Federico Nardari, 2006, Measuring short-term international stock market efficiency, Working Paper

Manufacturing Processes of Bleach

Manufacturing Processes of BleachIntroductionHousehold Bleach is one of the most cooperateful tools in most Ameri mass plates. thither be two main classes of household bleach centilitre bleaches and non- centiliter bleaches. All of these bleaches are in a class of chemicals known as oxidative agents, content that they cause a chemical reaction called oxidation when they come into contact with certain stains, certain germs or other organisms, and sometimes clothing dyes. Bleach is a very profitable chemical, both around the house and for large scale use. You throne use bleach to remove stains on clothing or to discolor your laundry. Its used to disinfect surfaces, too, especially in the kitchen and bathroom. You may bear tried bleach to remove mold and mildew. Hospital personnel use bleach as a disinfectant, hotels use bleach to unclouded and disinfect bed linens and surfaces, and restaurants disinfect food preparation surfaces with centilitre bleach. People use chlorine i n fluid pools to keep the water clean and raise the pH, and in much smaller concentrations to help keep municipal water supplies free of harmful organisms. Companies sometimes channel chlorine bleach to industrial wastewater to reduce odor, and chlorine is used by the glass, chemical, pharmaceutical, textile, agriculture, paint and paper industries. With its m each uses, bleach its a very familiar product to most people. While the word bleach entered the English language around the year 1050, bleach containing sodium hypochlorite was first manufactured in the U.S. in 1913, for use as an institutional disinfectant and a water treatment. Before that, chemicals such as borax, ammonia and lye were the most common bleaches in the U.S., and bleaches made apply chlorine were generally too expensive to manufacture until the 20th century. Clorox Chemical, later called the Clorox Company, first gave samples of bleach to consumers for household use in 1922 source American Chemistry Council . Since chlorine bleach was faster and to a greater extent effective than the bleaches people had been using, it quickly became the most popular household bleach. Today, when we say, bleach, we usually mean chlorine bleach. So what exactly is chlorine bleach, and how does it work? Humans squander been whitening fabrics for centuries ancient Egyptians, Greeks, and Romans bleached materials. As early as 300 B.C., soda ash, prepared from burned seaweed, was used to clean and whiten cloth. During the Middle Ages, the Dutch perfected the bleaching of fabrics in a impact called crofting, whereby fabrics were spread out in large fields for maximum sunlight exposure. textile mills as far away as Scotland shipped their material to the Netherlands for this bleaching. The practice quickly spread throughout Europe, and bleaching fields were documented in Great Britain as early as 1322. In 1728 a bleaching company using Dutch methods went into business in Galloway, Scotland. In this process, the fabrics were soaked in a lye ascendant for several days, thence bucked, or washed clean. The fabrics were then spread out on the grass for weeks at a time. This process was repeated five or six times until the desired whiteness was achieved. Next, the fabric was treated with sour milk or buttermilk, and again bucked and crofted. This method was lengthy and tedious, and it monopolized large tracts of land that could have been used for farming. Late in the 18th century, scientists discovered a chemical that had the same effect as crofting, but yielded much quicker results. In 1774, Swedish chemist Karl Wilhelm Scheele discovered the chemical element chlorine, a highly irritating, green-yellowish gaseous halogen. In 1785, the French scientist Claude Berthollet rear that chlorine was an excellent whitening agent in fabrics. Some mill operators attempted to expose their fabrics to chlorine gas, but the process was so cumbersome and the fumes so strong that these attempts were so on abandoned. Near Paris, in the town of Javel, Berthollet began a small facility for the manufacture of a new product called Eau de Javelle. The bleaching powderise consisted of potash (soda ash) which had absorbed chlorine gas. In 1799, another bleaching powder was invented by Scottish chemist Charles Tennant. In the early years of the Industrial Revolution, his patented lime powder was widely used to whiten a physical body of fabrics and paper products. To make the bleaching powder, slaked lime (lime treated with water) was spread thinly over the concrete or lead floor of a large room. centilitre gas was pumped into the room to be absorbed by the lime. though an effective whitener, the powder was chemically unstable. It was The raw materials for making household bleach are chlorine, erosive soda, and water. The chlorine and acidic soda are produced by putting direct current electricity through a sodium chloride common salt tooth root in a process called electrolysis. co mmonly used until around World War I, when tranquil chlorine and sodium hypochlorite solutions-the forerunners of modern household bleach-were introduced. About this time, researchers found that injecting salt water with electrical current broke down the salt (sodium chloride) molecules and produced a compound called sodium hypochlorite. This discovery enabled the mass production of sodium hypochlorite, or chlorine, bleach.Types of BleachToday, bleach is found in nearly every household. It whitens fabrics and removes stains by a chemical reaction that breaks down the undesired color into smaller particles that can be easily removed by washing. The two types of household bleach are chlorine bleach and peroxide bleach. hydrogen peroxide bleach was introduced in the 1950s. Though it helps to remove stains, especially in higher wash temperatures, it will not bleach most colored materials and does not weaken fabrics, as does sodium hypochlorite bleach. peroxide bleach does not disinfec t and is commonly added to laundry detergents which are advertised as color-safe. It also has a longer shelf life than chlorine bleach. Peroxide bleach is more commonly used in Europe, where washing machines are manufactured with inner heating coils that can raise the water temperature to the boiling point. The more common form of household bleach in the U.S. is chlorine bleach. It is most effective in removing stains and disinfecting fabrics. Chlorine bleach is cheap to manufacture and effective in both warm and hot wash temperatures. However, it has strong chemical properties which can weaken textile fibers. The disinfecting properties of chlorine bleach can also be useful outside the laundry. Chlorine bleach disinfects drinking water where groundwater contamination has occurred, as it is a powerful germicide. It was first used to sanitize drinking water in New York Citys Croton Reservoir in 1895, and is approved by the government for sanitizing equipment in the food industry. I n recent years, bleach has been promoted by community health activists as a low-cost method of disinfecting the needles of intravenous drug users.Raw MaterialsThe raw materials for making household bleach are chlorine, caustic soda, and water. The chlorine and caustic soda are produced by putting direct current electricity through a sodium chloride salt solution in a process called electrolysis. Sodium chloride, common table salt, comes from either mines or underground wells. The salt is dissolved in hot water to form a salt solution, which is then treated for impurities before it is reacted in the electrolytic cell.The Manufacturing ProcessPreparing the components 1 Caustic soda is usually produced and shipped as a concentrated 50% solution. At its destination, this concentrated solution is diluted with water to form a new 25% solution. 2 Heat is created when the water dilutes the strong caustic soda solution. The diluted caustic soda is cooled before it is reacted. The chemic al reaction 3 Chlorine and the caustic soda solution are reacted to form sodium hypochlorite bleach. This reaction can memorize place in a batch of about 14,000 gallons or in a continuous reactor. To create sodium hypochlorite, liquid or gaseous chlorine is circulated through the caustic soda solution. The reaction of chlorine and caustic soda is essentially instantaneous. Cooling and purifying 4 The bleach solution is then cooled to help prevent decomposition. 5 Often this cooled bleach is settled or filtered to remove impurities that can discolor the bleach or catalyze its decomposition. Shipping 6 The finish sodium hypochlorite bleach is shipped to a bottling plant or bottled on-site. Household-strength bleach is typically 5.25% sodium hypochlorite in an aqueous solution.Quality ControlIn the bleach manufacturing facility, the last sodium hypochlorite solution is put through a series of filters to extract any left-over impurities. It is also tested to make certain that i t contains exactly 5.25% sodium hypochlorite. golosh is a primary concern at manufacturing plants because of the presence of volatile chlorine gas. When the chlorine is manufactured outside the reactor facility, it travels in liquid form in specially designed railroad tank cars with double walls that will not rupture in the event of a derailment. On arrival at the plant, the liquid chlorine is pumped from the tank cars into holding vat.. As a safety measure, the tank cars have shutoff valves that work in conjunction with a chlorine maculation system. In the event of a chlorine leak, the detection system triggers a device on the tank that automatically stops the transmission of the liquid in 30 seconds. Inside the facility, chlorine vats are housed in an enclosed area called a car barn. This enclosed room is equipped with air scrubbers to eliminate any escaped chlorine gas, which is harmful to humans and the environment. The vacuum-like scrubber inhales any chlorine gas from the e nclosed area and injects it with caustic soda. This turns it into bleach, which is incorporated into the manufacturing process. Despite these precautions, safety and give notice drills are scheduled regularly for plant personnel.Special Considerations in PackagingHousehold sodium hypochlorite bleach was introduced to Americans in 1909 and sold in steel containers, then in glass bottles. In the early 1960s, the introduction of the tractile jug brought a cheaper, lighter, and nonbreakable packaging alternative. It reduced transportation costs and protected the safety of workers problematical in its shipping and handling. Additionally, the thick plastic did not permit ultraviolet light to reach the bleach, which improved its chemical stability and effectiveness. In recent years, how-ever, plastic containers have become an environmental concern because of the time it takes the material to decompose in a landfill. Many companies that depend on plastic packaging, including bleach manuf acturers, have begun to reduce the amount of plastic in their packaging or to use recycled plastics. In the early 1990s, Clorox introduced post-consumer resins (PCR) in its packaging. The newer bottles are a blend of virgin high-density polyethylene (HDPE) and 25% recycled plastic, primarily from clear milk jug-type bottles.Consumer SafetyThe bleach manufacturing industry came under fire during the 1970s when the public became concerned about the effects of household chemicals on personal health. Dioxin, a carcinogenic byproduct of chemical manufacturing, is often found in industrial products used to bleach paper and wood. In its utmost bottled form, common sodium hypochlorite bleach does not contain dioxins because chlorine must be in a gaseous state for dioxins to exist. However, chlorine gas can form when bleach comes into contact with acid, an ingredient in some toilet-bowl cleaners, and the labels on household bleach contain specific warnings against such combination. In add ition to the danger of dioxins, consumers have also been concerned about the toxicity of chlorine in sodium hypochlorite bleach. However, the laundry process deactivates the potentially toxic chlorine and causes the formation of salt water. After the rinse water enters the water system through the household drain, municipal water filtration plants remove the remaining traces of chlorine.

The Allegory of the Cave Essay -- Platos Republic

In Platos Republic, the great philosopher describes what is needed to action a perfect society. He addresses several(prenominal) subjects still debated in todays society, such as justice, gender roles, and the proper form of education. He discusses these issues through his main character, Socrates. Socrates, an new(prenominal) well-known philosopher for his time, happens upon a group of men, and what begins as a modest question, leads into a series of debates, metaphors, and allegories. Perhaps the most discussed allegory in todays popular culture is the Allegory of the Cave. Over the past decade, several movies gift mimicked the fantasy, the most profitable being the Matrix Trilogy. But what makes this story so fascinating? Through it, Plato attempts to map a mans journey through education. The map apply is another metaphor the Line. He explains the rewards for those who reach the top of the Line, and the significance of those who fall short. He also tries to answer the important question, how does a citys ruler view political relation and education, once he has reached true understanding? Platos fantasy begins in Book VII, 514a, with a dismal view of humanity, told by Socrates. He describes a world in which people live in a cave from birth, never seeing any sign of daylight. Theyre heads are bound to the wall in such a way that they cannot look at either side of them, nor behind them. The people are ignorant of all their surroundings except for what is directly in front end of them. Socrates goes on to describe a massive fire behind the people, and behind the fire, a partial wall. On top of the wall stand several statues of people, animals, and other various objects. Out of sight from the bounded prisoners are another group of people who manipulate the ... ... of the Line Imagination, Belief, Thought, and Understanding. When he completes the Line, he give ways a philosopher-king, ruler everywhere the city. The guardian then returns to the cave to help the others turn around and become educated. They perform this charity because they strive for the benefit of the city, rather than themselves. In contrast, the prisoners who refuse to become educated must not participate in governing, because their motives are set on benefiting themselves instead of the people as a whole. Through these points, Plato explains the views of the philosopher-king. The ruler views politics as a privilege meant only to be experienced by the educated, and he views education as the ultimate goal in life to achieve understanding of the world around him. Through these ideals, Plato believes that his ruler will be able to properly lead his perfect Republic.

Essay --

Fish constitutes a key source of animal protein for overmuch of the balls population.1 Global fishery catches from marine ecosystems were highest in the mid-1980s and have been decreasing ever since despite increasing fishing cause 2. Many of the lands oceans wild fish stocks are completely exploited, so the capture fisheries are no longer sustainable. In 2004 theUnited Nations State of the Worlds Fisheries subject field indicated that 52 percent of the oceans wild fish stocks are fully exploited.3. In response to the decline of wild fisheries, many of the countries have put their effort to aquaculture. Aquaculture is the demesne of aquatic plants and animals. FAO placed the global Aquaculture at 60 million tonnes in 2010,1, which is about 41.2 % of the total fish deed in the World. European partnership (EU) countries channel to 4% of the world aquaculture production. The value of EU aquaculture production was 3.1 billion for 1.26 million tonnes of production in 20104. Ava ilable data show a evolution offend estimated at 8 million tonnes surrounded by the level of consumption of seafood in the EU and the volume of captures from fisheries. Thus the European Union is giving a precession to elaboration of Aquaculture in its Members countries. Because of the many issues involved aquaculture, there is a deliberate measure by the EU to keep up policies which will agree that the expansion of aquaculture is in done in an environmentally, socially and economically sustainable way by member countries. Here I discuss the general concepts of aquaculture and the signification of the EU aquaculture policies under the EU Union common fisheries policy (CFP) for the appendage of aquaculture in the region. I also compare these policies with other ma... ...ave led to success of chinaware aquaculture acknowledge availability of market, diverse and diversity of fish products. Prioritization of the aquaculture as important sector of the economy also contributes to the signifi stackce difference in production between the EU and china.13The major differences that can be seen between aquaculture in China and in the European union is that in china aquaculture production is more pore to production while the European Union focuses on the Environmental challenges. ConclusionThe aquaculture sector has a strategic importance in contribution to food bail and its growth is very promising especially under the blue growth economy. Despite the many challenges facing the aquaculture industry in the EU the growth can be realized if the polices and strategies under the CFP for aquaculture are implemented by the member countries. Essay -- Fish constitutes a key source of animal protein for much of the worlds population.1 Global fishery catches from marine ecosystems were highest in the mid-1980s and have been decreasing ever since despite increasing fishing effort 2. Many of the worlds oceans wild fish stocks are completely exploited, so the capture fisheries are no longer sustainable. In 2004 theUnited Nations State of the Worlds Fisheries report indicated that 52 percent of the oceans wild fish stocks are fully exploited.3. In response to the decline of wild fisheries, many of the countries have put their effort to aquaculture. Aquaculture is the farming of aquatic plants and animals. FAO placed the global Aquaculture at 60 million tonnes in 2010,1, which is about 41.2 % of the total fish production in the World. European Union (EU) countries contribute to 4% of the world aquaculture production. The value of EU aquaculture production was 3.1 billion for 1.26 million tonnes of production in 20104. Available data show a growing gap estimated at 8 million tonnes between the level of consumption of seafood in the EU and the volume of captures from fisheries. Thus the European Union is giving a priority to expansion of Aquaculture in its Members countries. Because of the many issues involved aquaculture, there is a deliberate measure by the EU to keep up policies which will ensure that the expansion of aquaculture is in done in an environmentally, socially and economically sustainable way by member countries. Here I discuss the general concepts of aquaculture and the significance of the EU aquaculture policies under the EU Union common fisheries policy (CFP) for the growth of aquaculture in the region. I also compare these policies with other ma... ...ave led to success of china aquaculture include availability of market, diverse and diversity of fish products. Prioritization of the aquaculture as important sector of the economy also contributes to the significance difference in production between the EU and china.13The major differences that can be seen between aquaculture in China and in the European union is that in china aquaculture production is more focused to production while the European Union focuses on the Environmental challenges. ConclusionThe aquaculture sector has a strategic i mportance in contribution to food security and its growth is very promising especially under the blue growth economy. Despite the many challenges facing the aquaculture industry in the EU the growth can be realized if the polices and strategies under the CFP for aquaculture are implemented by the member countries.