Plant Medicines in Cancer Treatment

Plant Medicines in Cancer Treatment Review of Literature Plants as therapeutic agents Plant medicines are the most widely used medicines in the world today. The use of herbs and plants as the first medicine is a universal phenomenon. Every culture on earth, through written or oral tradition, has relied on the vast variety of natural chemistry found in healing plants for their therapeutic properties (Serrentino 1991). Plants with therapeutic potential may be defined as any plant that can be put to culinary or medicinal use. Recent researches found that food and their constituents act in a manner similar to modern drugs without the dreaded side effects (Serrentino 1991). Sometimes plant medicine is viewed as complementary medicine, working closely with allopathic drugs. Nearly 5.1 billion people worldwide employ natural plant-based remedies as their primary medicines for both acute and chronic health problems, from treating common cold to controlling blood pressure and cholesterol (Stockwell, 1988). Most of the drugs were substances with a particular therapeutic action extracted from plants. Some medicines, such as the cancer drug Taxol from Taxus brevifolia and the anti-malarial quinine from Cinchona pubescens are manufactured from the plants. Other medicinal agents such as pseudoephedrine originally derived from ephedra species and methylsalicylate, derived from gaultheria procumbens are now synthesized. Plant medicines remain indispensable to modern pharmacology and clinical practice. Much of the current drug discovery and development process are plant-based, and new medicines derived from plants are inevitable. Functional foods A food can be regarded as a functional food if it is demonstrated to affect one or more target functions in the body beyond adequate nutrition and improves health/well-being or reduces the risk of diseases (Tsao and Akhtar, 2005). On this basis, a functional food can be a natural food, a food to which a positive component has been added, or from which a deleterious component has been removed or a food where the nature of one or more components has been modified (Tsao and Akhtar, 2005). While searching for new sources of functional food, attention has been paid to vegetables from the Cruciferae family, which more often used in the human diets. The cruciferous vegetables may thus become a potential source of a nutritious food or food ingredients. Recent research showed that cruciferous vegetables contain an appropriate amount of bioactive compounds such as GLs, ITCs, tocopherols, L-ascorbic acid, vitamin B, reduced glutathione, inositol phosphates and polyphenolic compounds [Nakamura e t al, 2001; Zielinski and Kozlowska, 2003; Zielinski et al, 2005; Takaya et al, 2003]. Cruciferous plants The family Cruciferae (Brassicaceae) is an economically important family with about 350 genera and 3000 species that includes several edible plants. Despite the great diversity among the crucifers, members of only a few genera are eaten. The most commonly eaten cruciferous vegetables belong to the genus Brassica that includes broccoli, cabbage, cauliflower, kale and Brussels sprouts. Other cruciferous vegetables used in the human diet such as radish, water cress, wasabi, horseradish, garden cress, Italian cress, Swiss chard and crambe belong to another genera of the family such as Raphanus, Nasturtium, Wasabia, Armoracia, Lepidium, Eruca, Beta and Crambe respectively. Cruciferous vegetables are important dietary constituents in many parts of the world and appear to account for about 10 15% of total vegetable intake, reaching almost 25% in countries with a high consumption (Bosetti et al, 2002; Chiu et al, 2003). However, regional pattern of crucifer consumption varies substantially in different parts of the world. The highest intake of cruciferous vegetable was reported to that of people in China, who consumed more than 100 g per day, representing about one-fourth of their total vegetable intake (Chiu et al, 2003). Other Asians and some Middle Eastern populations in Japan, Singapore, Thailand and Kuwait also have a relatively high intake of cruciferous vegetables, ranging from 40 80 g per day (Bosetti et al, 2002; Seow et al, 2002; Shannon et al, 2002; Memon et al, 2002). However, the only study carried out in India (Rajkumar et al, 2003) showed a lower daily intake of cruciferous plants, of about 17 g per day. In North America, the daily estima ted consumption was in the range of 16 40 g per day (Lin et al, 1998) and in South America, it was about 3 15 g per day (Atalah et al, 2001). The daily intake of cruciferous vegetables was reported to be about 5 30 g per day in Europe (Bosetti et al, 2002), 50 g per day in Australia (Nagle et al, 2003) and 15 g per day in South Africa (Steyn et al, 2003) respectively. Raphanus sativus R. sativus is believed to have originated in southern Asia and was cultivated in Egypt. The first cultivated R. sativus was black variety and later on white and red R. sativus were developed. It was highly esteemed in ancient Greece, and the Greek physician Androcydes ordered his patients to eat R. sativus as a preservative against intoxication. The Japanese white R. sativus, also named daikon, is the vegetable for which the literature reports the highest per capita consumption, quoted at 55 g per day in Japan (Talalay and Fahey, 2001). In addition to this, Japanese also consumes R. sativus sprouts under the name of Kaiware Daikon. Varieties of R. sativus There are six main varieties of R. sativus such as Daikons, Red Globe, White Globe, Black, White Icicles and California Mammoth White Daikons (R. sativus L) This variety is native to Asia. They are large and carrot-shaped, have a white flesh that is juicy and a bit hotter than a red radish, but milder than black. Red Globe (R. sativus var. red) This variety is the most popular in the United States. It is small, round or oval shaped, referred to as button red radishes and have a solid crisp flesh. White Globe (R. sativus var.white) This variety is small and oval shaped, referred to as hailstone or white button. They have white flesh and milder than the red variety. Black (R. sativus var. niger) This variety is thought to be native to Egypt and Asia. They are turnip-like in size and shape. They are quite pungent and drier than other varieties of radishes. White Icicles (R. sativus L var. thin) This variety is long and tapered. They have a white flesh that is milder than the red variety. California Mammoth White (R. sativus L var. large) A larger variety than the white icicle, these varieties have oblong- shaped roots and their flesh is slightly pungent. Nutritive value of R. sativus R. sativus root and its leafy part are ideal vegetables as they provide an excellent source of vitamin C. Leafy part contains almost six times the vitamin C content of its root and also a good source of calcium and iron. R. sativus is also a good source of potassium and folic acid. It is very low in fats. Approximately, 100 g of raw vegetable provides roughly 20 Kcal, coming largely from carbohydrates (Table 2.1). Thus R. sativus is a dietary food that is relatively filling for its caloric value. Some sources list R. sativus as being rich in dietary fiber, whereas other sources differ in respect of its roughage content (USDA Nutrient Database, 1999; Duke and Ayensu, 1985). Health benefits of R. sativus (Traditional usage of R. sativus) According to Hakeem Hashmi, an eminent Unani physician from India, R. sativus is unparallel in curing any kind of ailments. All the parts of R. sativus including its seed, stem, root and leaves are used in food and medicine. R. sativus is a unique vegetable having a hot and cold effect on the body simultaneously. R. sativus, like other members of the cruciferous family (cabbage, kale, broccoli, Brussels sprouts) contains cancer-protective properties. Liver and gall bladder disorders Throughout the history, R. sativus root and seeds have been effective when used as medicinal food for liver disorders. They contain sulfur-based compounds such as GLs and ITCs that increase the flow of bile and help to maintain healthy gallbladder and liver (Chevallier, 1996). They are useful in treating jaundice and also an excellent remedy for gall bladder stone. Kidney disorders R. sativus root, seeds and leaves are diuretic in nature and increase the urine output. Their diuretic properties help to flush out the toxins accumulated in the kidneys and protect them from infections and inflammatory conditions. It is an old belief that R. sativus can aid in the treatment as well as prevention of kidney stones (Chopra et al, 1986). Respiratory disorders R. sativus is an anti-congestive and relieves congestion of the respiratory system. It has found to be beneficial in problems associated with bronchitis (Bown, 1995) and asthma (Duke and Ayensu, 1985). Skin disorders R. sativus helps to cure skin disorders such as leucoderma, rashes, cracks, etc and also refreshes the skin by maintaining the moisture content of the skin (Duke and Ayensu, 1985). Digestive disorders R. sativus root, seeds and leaves are rich in roughage (indigestible carbohydrates) which facilitates digestion, retain water and relieve constipation (Chopra et al, 1986). They also soothe the digestive system and stimulate appetite (Chevallier, 1996) Nervous and vascular disorders R. sativus decreases nervous tensions and is also useful in enhancing blood circulation. It is a remedy for insomnia, hypochondria and irritative conditions of the central nervous system (Panda, 1999). Other benefits R. sativus is germicidal and suppresses phlegm. It is a good appetizer, mouth fresher, laxative, regulates metabolism, remedy for headache, acidity, piles, nausea, obesity, sore throat, whooping cough, dyspepsia, etc (Nadkarni, 1976; Kapoor, 1990). Chemical constituents of R. sativus GLs are an important and unique class of secondary plant metabolites found in the seeds, roots and leaves of R. sativus (Daxenbichler et al, 1991; Blazevic and Mastelic, 2009). GLSs include several naturally occurring thioglucosides with a common structure (Figure 2.2) characterized by side chains (R) with varying aliphatic, aromatic and heteroaromatic carbon skeletons, all presumably derived from amino acids by a chain-lengthening process and hydroxylation or oxidation (Larsen, 1981). In the intact cell, GLs are separated from thioglucosidase (EC 3.2.3.11), an enzyme generally known as myrosinase. When the plant cell structure is damaged, myrosinase catalyzes the hydrolysis of GLs to yield D-glucose, sulfate and a series of compounds including isothiocyanates, thiocyanates and nitriles, depending on both the substrate and the reaction conditions, especially the pH (Figure 2.2). GLs are also hydrolyzed by thioglucosidase activity of the intestinal microflora (Jeffery and Jarrell, 2001). 4-(methylthio)-3-butenyl glucosinolate (glucoraphasatin), 4-(methylsulfinyl) butyl glucosinolate (glucoraphanin) and 4- (methylsulfinyl)-3-butenyl glucosinolate (glucoraphenin) are the most predominant GLs in the root and seeds of R. sativus (Daxenbichler et al, 1991; Carlson et al, 1985). These GLs on hydrolysis by myrosinase yield MTBITC, sulforaphane and sulforaphene respectively. GLs are not uniformly distributed and are highest in the distal end of the root, decreasing in upper root sections with the lowest level in vegetative tops (Esaki and Onozaki, 1980). Apart from GLs and their breakdown products, R. sativus also contains polyphenolics such as phenolic acid, flavonoids and anthocyanins. Several polyphenolic compounds including sinapic acid esters and kaempferol were isolated from R. sativus sprouts (Takaya et al, 2003). Twelve acylated anthocyanins (pelargonidin) were isolated from R. sativus red variety (Otsuki et al, 2002). Phytochemical screening showed the presence of other phytochemicals such as triterpenes, alkaloids, saponins and coumarins in R. sativus seeds (Mohamed et al, 2008). The myrosinase catalyzed hydrolysis of glucosinolates. (Adapted from Rusk et al, 2000) Novel classes of plant defensins (small basic cysteine rich peptides) such as Raphanus sativus antifungal peptide 1 and 2 (RsAFP1 and RsAFP2) were isolated from the seeds of R. sativus (Terras et al, 1992a). RsAFP1 and RsAFP2 are highly basic oligomeric proteins composed of small (5 KDa) polypeptides that are rich in cysteine. Both RsAFP1 and RsAFP2 have a broad spectrum antifungal activity and show a high degree of specificity to filamentous fungi (Terras et al, 1992b). They are active against both phytopathogenic fungi such as Fusarium culmorum and Botrytis cinerea (Terras et al, 1992b), human pathogenic fungi such as Candida albicans (Aerts et al, 2007) and occasionally possess antibacterial activity. However, they are non-toxic to humans and plant cells. R. sativus 2S storage albumins were identified as second novel class of antifungal protein (Terras et al, 1992a). They also inhibit the growth of different plant pathogenic fungi and certain bacteria (Terras et al, 1992a). At least eight distinguishable isoperoxidases were isolated and purified to apparent homogeneity from Korean R sativus roots. Among them are two cationic isoperoxidases such as C1 and C3 and four anionic isoperoxidases such as A1, A2, A3n and A3 (Lee and Kim, 1994). Plant peroxidases play an important role in several physiological functions such as removal of peroxide, oxidation of indole-3-acetic acid and toxic reductants, wound healing and cell wall biosynthesis (Hammerschmidt et al, 1982). Further, peroxidase represents an important component of an early response in plants to pathogen attack and plays a key role in the biosynthesis of lignin, which limits the extent of pathogen spread (Bruce and West, 1989). The products of this enzyme in the presence of a hydrogen donor and hydrogen peroxide have antimicrobial activity and even antiviral activity (Van Loon and Callow, 1983). Recently, a novel heme peroxidase intrinsically resistant to H2O2 was isolated from R. sativus (Japanese d aikon), which showed relatively stronger oxidative stability than that of reference horse radish peroxidase (HRPA2) (Rodrà ­guez et al, 2008). Biological activities of R. sativus Evidence from numerous investigations reveals that the biological and pharmacological functions of R. sativus are mainly due to its GLs and its breakdown products ITCs (Esaki and Onozaki, 1982; Nakamura et al 2001; Barillari et al, 2006; Papi et al, 2008). These compounds provide to R. sativus its characteristic odor and flavor as well as most of their biological properties. GLs and/or ITCs have long been known for their fungicidal, bacteriocidal, nematocidal and allelopathic properties (Brown et al, 1991) and have attracted intense research interest because of their cancer chemoprotective attributes (Fahey et al, 2001; Verhoeven et al, 1997). Polyphenolics, alkaloids, saponins, isoperoxidases and antifungal peptides are also accountable for significant part of the health benefits of R. sativus. These constituents are reported to exhibit several biological effects, including radical scavenging activity (Takaya et al, 2003), gut stimulatory, uterotonic and spasmogenic effects (Gilani and Ghayur, 2004; Ghayur and Gilani, 2005), anti-hyperlipidemic activity (Wang et al, 2002) and anti-atherogenic effects (Suh et al, 2006) and would perhaps work synergistically with GLSs and ITCs of R. sativus. Antioxidant activity Damage to proteins, lipids and DNA by reactive oxygen species (ROS) and reactive nitrogen species (RNS) can lead to a variety of chronic diseases such as cancer, cardiovascular, inflammatory and age-related neurodegenerative diseases (Borek, 1997; Richardson, 1993). ROS/RNS can damage cell membranes, disrupt enzymes, reduce immunity (Ahsan et al, 2003) and induce mutations (Loft and Poulsen, 1996). ROS/RNS are by-products of normal aerobic metabolism and could occur during mitochondrial/microsomal electron transport chain, phagocytic activity or generated from oxidase enzymes and transition metal ions (Nohl et al, 2003; Aruoma et al, 1989). Other sources of ROS/RNS are environmental factors such as pollution, sun damage, cigarette smoke or even some kinds of the foods (Schroder and Krutmann, 2004). These reactive species and the resulting oxidative damages are usually counteracted by the antioxidant defense mechanisms (Bagchi and Puri, 1998). Recent studies evidence that plant-based diets, particularly those rich in vegetables and fruits, provide a considerable amount of antioxidant phytochemicals such as vitamins C and E, glutathione, polyphenolics, sulfur containing compounds and pigments, which offer protection against cellular damage (Dimitrios, 2006). Vitamins Ascorbic acid is found to be the most effective antioxidant in inhibiting lipid peroxidation initiated by a peroxyl radical initiator among several types of antioxidants including a-tocopherol (Fei et al, 1989). Ascorbic acid is also capable of scavenging hydrogen peroxide, singlet oxygen, superoxide and hydroxyl radicals efficiently (Fei et al, 1989). It is also involved in the regeneration and recycling of tocopherols and ß-carotene (Niki et al, 1995). Numerous studies have shown that ascorbic acid is effective in lowering the risk of developing cancers (Block, 1991) and cardiovascular diseases (Trout, 1991). In spite of the overwhelming evidence on the health benefits, however, there are reports that demonstrated the pro-oxidant activity of ascorbic acid (Podmore, 1998). Tocopherols are essential vitamins with their major role as antioxidants in protecting polyunsaturated fatty acids (PUFAs) and other components of cell membranes and low-density lipoprotein (LDL) from oxidation , thereby preventing the onset of heart diseases (Rimm et al, 1993). Polyphenolics Polyphenolics is an extremely comprehensive phrase that covers many different subgroups of phenols and phenolic acids. These compounds are most commonly present in fruits and vegetables. They are essential to the physiology of plants, being involved in diverse functions such as lignification, pigmentation, pollination, allelopathy, pathogen/predator resistance and growth (Haslam, 1996). Polyphenolics include single-ring structure such as hydroxybenzoic acids and hydroxycinnamic acids and multi-ring structure such as flavonoids, which can be further classified into anthocyanins, flavan-3-ols, flavones, flavanones and flavonols. Some of the flavonoids such as flavan-3-ols can be found in their dimeric, trimeric and polymeric forms. Most of the polyphenolics are often associated or conjugated with sugar moieties that further complicate the polyphenolic profile of vegetables. Polyphenolics are especially important as antioxidants, because they have high redox potentials, which permit the m to act as reducing agents, hydrogen donors, singlet oxygen quenchers and metal chelator (Kahkonen et al, 1999) and alleviate free radical mediated cellular injury (Shahidi and Wanasundara, 1992). The antioxidant ability of individual polyphenolics may differ, but, as a group, they are one of the strongest groups of antioxidants. The antioxidant activity of a polyphenolic compound is chiefly determined by its structure, in particular the electron delocalization over an aromatic nucleus (Tsao and Akhtar, 2005). When these compounds react with a free radical, delocalization of the gained electron over the phenolic antioxidant and the stabilization of the aromatic nucleus by the resonance effect take place that prevent the continuation of the free radical-mediated chain reaction (Tsao and Akhtar, 2005). Sulfur-containing compounds GLs are a group of sulfur-containing compounds found in the cruciferous plants such as R. sativus, broccoli, cabbage, mustard, wasabi etc. These compounds are found to be strong antioxidants, which are indeed through activation of detoxification enzyme mechanisms for the efficient removal of xenobiotics, rather than through direct radical scavenging capability (Zhang and Talalay, 1998). This property of GLs and its hydrolysis products ITCs is considered as one of the major contributors to its anti-cancer activity (Zhang and Talalay, 1998). Antioxidant activity of R. sativus R. sativus is one of the major sources of dietary phenolic acids and flavonoids, which are mostly present as sugar conjugates (Takaya et al, 2003). The major phenolic acids found in R. sativus sprout are sinapic acid and ferulic acid, which are present in conjugated form as 1-sinapoyl-1-ß-D-glucopyranoside, ß-D-(3-sinapoyl) frucofuranosyl -a-D-(6-sinapoyl) glucopyranoside and 1-feruloyl-ß-D-glucopyranoside (Takaya et al, 2003). The major flavonoids present in R. sativus sprouts is kaempferol that occurs in a conjugated form as kaempferol-3,7-O- a-L-dirhamnopyranoside and kaempferol-3-O- a-L-rhamnopyranosyl-(1-4)- ß-D-glucopyranoside (Takaya et al, 2003). Lugasi et al (1998) demonstrated the strong antioxidant property of squeezed juice extracted from a black R. sativus root through its ability to donate electrons, chelate metal ions and scavenge free radicals in a H2O2/ ·OH-luminol system. Since HPLC analysis revealed the presence of a considerable amount of GLs degradation products and polyphenols in the squeezed juice of black R. sativus, antioxidant activity of black R. sativus root could be attributed to these compounds. Takaya et al (2003) tested methanolic extracts from 11 different plants including Daikon R. sativus sprouts for their ability to scavenge free radicals. Daikon R. sativus sprouts proved to be the most potent, almost 1.8 times more effective than Vitamin C. Souri et al (2004) studied the antioxidant activity of 26 commonly used vegetables in Iranian diet and found that methanolic extract of R. sativus leaf significantly inhibited the peroxidation of linoleic acid as compared to standard antioxidant such as a-tocopherol and quercetin. Katsuzaki et al (2004) found that hot water extract of Daikon R. sativus extract showed more significant antioxidant activity than the extract obtained at an ambient temperature. L-tryptophan was isolated and identified as the compound responsible for the antioxidant activity. They also found that L-tryptophan changed to 5-hydroxy tryptophan (5-HTP), a precursor to serotonin in the rat liver microsome model system. A plant-based 5-HTP supplement is popular for its anti-depressant, appetite suppressant and sleep aiding properties. Lugasi et al (2005) further demonstrated that squeezed juice from black R. sativus significantly alleviated the free radical reaction in rats with hyperlipidaemia by decreasing the lipid peroxidation reactions and by improving the antioxidant status. Recent study also showed that R. sativus extract reduced the extent of lipid peroxidation in a dose dependent manner in rat liver homogenate treated with cumene hydroperoxide by increasing the levels of reduced glutathione and thereby protecting the liver from the toxin induced oxidative damages (Chaturvedi, 2008). Salah-Abbes et al (2008a) showed the protective effect of Tunisian R. sativus root extract against toxicity induced by zearalenone in mice by virtue of its ability to alleviate oxidative stress through stimulation and improvement of the antioxidant status. Polyphenolics in R. sativus may act in a synergistic or additive manner with GLs and/or ITCs and exert their antioxidant activity through inhibition of lipid peroxidation, enhancing the cellular antioxidant enzymes and increasing the glutathione in the cells. Apart from these phytochemicals, R. sativus also contain several classes of peroxidases that could play a significant role in the elimination of toxic peroxides and thus reduce the impact of free radical mediated cellular injury (Wang et al, 2002). Antimicrobial activity Infectious diseases are the worlds leading cause of untimely death, killing approximately 50,000 people every year. Bacteria have a remarkable ability to develop resistance to most pharmaceutical antibiotics. An increase in such antibiotic-resistant bacteria are menacing the human population with a recurrence of infectious diseases that were once thought to be under control, at least in developed countries (Pinner et al, 1996). These antibiotic-resistant bacteria have also caused unique problems in treating infections in patients with cancer and AIDS (Dennesen et al, 1998). Since tenacious and virulent bacteria develop immunity to solitary antibiotics at an alarming speed, there is an imperative need for a holistic targeted approach to search for novel antimicrobials from natural sources, especially from plant kingdom. Long before mankind ascertained the existence of microbes, the fact that certain plants had therapeutic potential was very well accepted. Since ancient times, man has used plants as the widespread remedial tool to treat common infectious diseases. Some of these traditional medicines are still included as part of the habitual treatment of various maladies. Bearberry (Arctostaphylos uva-ursi) and cranberry juice (Vaccinium macrocarpon) are employed to treat urinary tract infections, while species such as lemon balm (Melissa officinalis), garlic (Allium sativum) and tee tree (Melaleuca alternifolia) are described as broad-spectrum antimicrobial agents (Heinrich et al, 2004). Plant based antimicrobials represent a vast unexploited source for medicines, which need to be explored further. They have an immense therapeutic potential as they are effectual in the treatment of infectious diseases while concomitantly alleviating many of the side effects that are frequently connected with synthetic antimicrobials (Cowan, 1999). Plant based anti-infective agents generally have manifold effects on the body and often act beyond the symptomatic treatment of the infectious diseases. Plants have a virtually unlimited capacity to produce secondary metabolites, especially for their defense against predation by microorganisms, insects and herbivores. Many of these secondary metabolites give plants their characteristic odors and also responsible for plant pigments. Antimicrobial phytochemicals are divided into several categories based on their structural similarity as follows: Phenolic acids These are the simplest bioactive phytochemicals consisting of a single substituted phenolic ring. Cinnamic acid and caffeic acids are the common representatives of this group. Phenolic acids are reported to be effective against viruses (Wild, 1994), bacteria (Brantner et al, 1996) and fungi (Duke, 1985). The number and site of the hydroxyl group on the phenol structure are considered to be related to their relative toxicity to microorganisms. Phenolic acids which are in the higher oxidized state are often more inhibitory towards microorganisms than the one with the lower oxidation state (Scalbert, 1991). Thus the mechanisms thought to be responsible for the antimicrobial activity of phenolic acid could include enzyme inhibition by the oxidized compound through interaction with SH groups or through nonspecific interaction with the microbial proteins (Mason and Wasserman, 1987). Quinones They are aromatic compounds with two ketone substitutions in the phenolic ring. They are ubiquitous in nature and show general antimicrobial properties (Duke, 1997). They are extremely active as they can switch between hydroquinone and quinone through oxidation/reduction reactions. Quinones bind with proteins irreversibly, leading to inactivation of proteins and loss of function (Stern et al, 1996). They may also make substrates unavailable to the microbes. Flavonoids They are phenolic structures containing hydroxyl groups. They are ubiquitous and are commonly found in fruits, vegetables, nuts, tea, wine, honey, etc. They are known to be effective antimicrobial compounds against a wide variety of microorganisms (Cushnie and Lamb, 2005). Catechins are the most extensively researched flavonoids for their possible antimicrobial activity due to their occurrence in green tea (Toda et al, 1989). Flavonoids have the ability to complex with extracellular proteins as well as with bacterial cell walls, rendering them inactive (Cushnie and Lamb, 2005). More lipophilic flavonoids may also have the ability to disrupt microbial membrane (Tsuchiya et al, 1996). Terpenoids and essential oils Essential oils are secondary metabolites that are highly supplemented in compounds based on an isoprene structure (Cowan, 1999). They are called as terpenes and usually occur as di, tri, tetra, hemi and sesquiterpenes. When the compounds contain extra elements such as oxygen, they are called as terpenoids. Camphor, farnesol, artemisin and capsaicin are the common examples of terpenoids. Terpenes and terpenoids are active against an array of bacteria (Habtemariam et al, 1993) and fungi (Rana et al, 1997). Previous research showed that terpenoids present in the essential oils of plants could be useful in the control of Listeria monocytogenes (Aureli et al, 1992). The mechanism action of terpenes is not yet established precisely, but is speculated to be due to the disruption of bacterial cell membrane by the lipophilic terpenoids (Mendoza et al, 1997). Alkaloids Alkaloids constitute large groups of compounds containing a nitrogen atom in a heterocyclic ring, with a broad range of biological activities. The first medically functional alkaloid was morphine isolated from Papaver somniferum (Fessenden and Fessenden, 1982). Alkaloids are generally found to have potent antimicrobial activity (Ghoshal et al, 1996). Solamargine, a glycoalkaloid from the berries of Solanum khasianum reported to be useful against HIV infection and intestinal infections associated with AIDS (McMahon et al, 1995). Berberine is an important and frequently studied member of the alkaloid group. It is potentially efficient against trypanosomes (Freiburghaus et al, 1996) and plasmodial infections (Wright et al, 1992). The mode of action responsible for the antimicrobial activity of alkaloids may be attributed to their ability to intercalate with DNA and arresting the metabolic activity of the bacterial cells (Phillipson and ONeill, 1987). Sulfur-containing compounds Sulfur-containing compounds encompass a wide array of compounds and usually found in the plants as glucosides (glucosinolates, alliin, etc). These glucosides, during the rupturing of the plant cell wall, are hydrolyzed into volatile sulfur compounds such as ITCs, allicin, allyl sulfide, diallyl disulfate, etc. Biological activity of sulfur-containing compounds is considered to be chiefly due to glucoside degradation products, as intact glucosides usually display much fewer biological activities than their subsequent hydrolysis products (Donkin et al, 1995). The mechanism of action responsible for the antimicrobial activity of sulfur-containing compounds varies. Antimicrobial activity of ITCs, degradation products of GLs, is thought to be related to its NCS group, in which the central carbon atom is highly electrophilic, which could interact irreversibly with

Television Violence Essay -- Media TV Violent Essays

Television Violence The media is everywhere in our lives. From billboards to SMS text messaging on cell phones, we cannot escape the media and its impact on daily life. Of the many impacts, television violence and the influence it has on youth is one of the most debated topics. Many experts, including some from the University of California, Santa Barbra, say that the amount and type of violence viewed results in violent actions performed by youth of all ages and violence continually affects them throughout their lives. Others are more skeptical and argue that the media is not the sole cause of youth violence; they believe that there are many other factors that contribute to the violent behaviors of youth. They see the condition more as a mixture of different situations that cause violence in youth, violence on television being just one of the factors. However, both sides of the argument understand that each individual is a separate situation and reacts differently to the violence portrayed. This essay will inform the reader of the claims both sides formulate to defend their argument and allow the reader to determine their own conclusion. Many studies over the past seven years have sought to prove that television and the violence portrayed does have a direct influence on youth and how they will deal with situations in real life. Out of the many studies, one of the most concrete and convincing is the National Television Violence Study (or NTVS) conducted by University of California Santa Barbra, University of North Carolina Chapel Hill, University of Texas at Austin and the University of Wisconsin Madison. This study observes not only the response of youth to various types of content but also observed the response of th... ...Media violence: Exposure and Content. Retrieved February 10, 2004 from http://www.surgeongeneral.gov/library/youthviolence/chapter4/appendix4bsec2.html#TelevisionFilm National Television Violence Study, ed. Federman. 3rd ed. Thousand Oaks, CA: Sage Publications, Inc, 1998 The American Academy of Child and Adolescent Psychiatry. (1999, April). Children and TV Violence. Retrieved February 10, 2004 from http://www.aacap.org/publications/factsfam/VIOLENCE.HTM Youth Violence: A Report of the Surgeon General. (Unknown). Appendix4b Retrieved February 10, 2004 from http://www.surgeongeneral.gov/library/youthviolence/chapter4/appendix4b.html Youth Violence: A Report of the Surgeon General. (Unknown) Media violence: Exposure and Content. Retrieved February 10, 2004 from http://www.surgeongeneral.gov/library/youthviolence/chapter4/appendix4bsec2.html#TelevisionFilm

Sydney Tar Ponds Essay -- Environmental Disaster

In 1901, an Boston based invertor group opened up a steel mill on the southeast side of Sydney harbor in Sydney, Nova Scotia. This mill was named DISCO, or Dominion Iron and Steel Company Limited, which was ultimately a subsidiary of DOMCO, or the Dominion Coal Company Limited. DOMCO coal was mined in Dominion, near Glace Bay and was used to make coke. Coke is a hard, grey, porous material, man-made from the coal and is used to fuel the blast furnaces for smelting the iron ore. (Coke (fuel), 2012) DOMCO along with DISCO merged with the Nova Scotia Steel and Coal Company or SCOTIA to from the British Empire Steel Corporation or BESCO in 1920. The company soon reorganized and in 1930 under the name Dominion Steel and Coal Corporation or DOSCO. In 1957 it was purchased by Toronto based aircraft manufacturing company, A.V. Roe Canada and in 1962 was once again sold, this time to Hawker Siddeley Canada, where it become a subsidiary. (Sydney Steel Corporation, 29) Hawker Siddeley ran the company smoothly until 1965 when they decided to eliminate all money moving operations. It was also around this time that it was announced that there were only around 15 operational years left for the Sydney coalmines and that after this opening new mines would be too expensive and that DOSCO would be getting out of the coal mining industry. The Sydney mill was very outdated compared to other mills in western and central Canada at this time. After an outcry for Cape Breton County residence, Prime Minister Lester B. Pearson, announced the creation of the Donald Commision led by J.R. Donald. The job of this commission was to launch a inquiry into the Cape Breton coal industry. They recommended that a federal crown corporation be set up to buy and mana... ... Contaminated material will still be filled with cement and then contained in the area they are in, none of the material will be incinerated. Then the entire area will be caped off and landscaped for future use The first phase of this was completed in late 2009 while the second stage began in Spring of 2010. (Tar ponds timeline, 2007) (Sydney Tar Ponds, 2012) Works Cited Coke (fuel). (2012, 04 02). Retrieved 04 08, 2012, from Wikipedia: http://en.wikipedia.org/wiki/Coke_(fuel) Sydney Steel Corporation. (29, 04 2011). Retrieved 04 2012, 08, from Wikipedia: http://en.wikipedia.org/wiki/Sydney_Steel_Corporation Sydney Tar Ponds. (2012, 04 07). Retrieved 04 08, 2012, from Wikipedia: http://en.wikipedia.org/wiki/Sydney_Tar_Ponds Tar ponds timeline. (2007, 01 29). Retrieved 04 08, 2012, from CBC News: http://www.cbc.ca/news/background/tarponds/timeline.html

psych paper notes :: essays research papers

1.  Ã‚  Ã‚  Ã‚  Ã‚  School violence starts out with the bully on the playground, or the pushing and shoving in the lunch line, but given the right set of circumstances what might have been prevented with some supervision instead turns into something deadly. 2.  Ã‚  Ã‚  Ã‚  Ã‚  The only common denominator that exists between them all is the fact that there is no one determining factor. 3.  Ã‚  Ã‚  Ã‚  Ã‚  School violence does not start in the school. Most behaviors are learned responses to circumstances and situations that are exhibited in our everyday life. Home life conditions are influences on all children. If a child grows up in a home where one of the parents is abused, whether verbally or physically, the child will take this as the norm. Studies have proven that a child living in an abusive home will himself become an abuser. Children who see violence view it as a solution to the problem. They see the stronger of the two components as the winner in the situation, and want to emulate the behavior. 4.  Ã‚  Ã‚  Ã‚  Ã‚  A survey conducted by the Loeber's group shows that parenting practices of severe discipline and voicing of negative attitudes towards young boys around the age of ten result in an increase of aggressive behavior in the school setting. Also the use of coercive methods to control children, such as the threat of violence for disobedience is another pathway to violent behavior 5.  Ã‚  Ã‚  Ã‚  Ã‚   Sibling violence can erupt setting the groundwork for later violence in the school setting. If a child can bully his or her sibling and get away with it then what is to stop them from attacking their peers at school. 6.  Ã‚  Ã‚  Ã‚  Ã‚  Lack of discipline can also cause a child to become self-absorbed. A parent who over indulges his child is instilling in the child a feeling that he can do no wrong. He may act out with the knowledge that he will not be punished. This child will grow up with a lack of empathy for others, and be void of moral values for his fellow man 7.  Ã‚  Ã‚  Ã‚  Ã‚  Violence on television is learned from a very early age with the watching of cartoons. These funny harmless half-hour shows that make us laugh are the first viewing of violence that our children see. What these shows are telling our children is that violence is ok. It makes them numb to the horror of the actual violence happening around them. Statistically speaking 47% of the violent acts on television do not harm the victim, 86% of the violent acts have no negative repercussions, no one dies, no one goes to jail, and no ones life is ruined.

Becoming a Police Officer Essay

Although being a police officer can be stressful, it can also be highly rewarding if public service is important to you. (Kara, 1999) When becoming a Police Officer, you are making a commitment to protect your community even if it means giving your life to do it. Despite what some people may think every police officer does their job they way they do it to make sure that your families are safe every night. Just like any job out there now a days you have to have an education. To be a police officer most places are now requiring a two degree. Going beyond a two year degree usually leaves you the opportunity to progress in your field of choice allowing for more job options. Being a Police Officer means that you have to first meet the requirements set forth by the department with which you are applying, have the unique set of skills to do your job efficiently, and you have to have the willingness to further your education to go further in your career. To be successful as a Police Officer there are some characteristics that you need. Some of these characteristics include having a level head, being able to think quickly on your feet, and have the ability to work well under pressure. You have to be able to work well with little to no supervision. This is a skill you need when working undercover and in the field. It is also important that you have self-confidence, and confidence in your ability to make decisions and take the lead in what could be a risky situation. Leadership skills are also important because the people of the community look to you to be able to solve issues and crime related issues. Having the capabilities to be a leader comes very important in the job as an officer. The whole community depends upon your ability to be a leader in their eyes. It’s highly important to have the ability to stay calm in highly stressful situations. If you are unable to stay calm in high pressure situations and emotional intense situations it will become hard for you to as an officer to function on a daily basis. Having patience (which can be difficult at times) and a good set of morals are also important skills an officer must have. An officer must be able to handle situations with patience and good communication skills. These come very handy while interviewing a suspect or even dealing with issues in the community. Having a good set of morals are important because as an officer of the law you must set the example and follow the laws yourself and not believe that you can get away with everything because you are above the law, because you are not. You are an enforcer of the law, so to enforce the law upon others you must also obey the laws yourself. You also should have a good sense of right and wrong to be able to encourage good behavi or to the public. The basic requirements to be a police officer are usually about the same, because most follow the civil service regulations when hiring officers. These requirements would include: Being a United States citizen, you have to be at least twenty-one years old, have a high school diploma or equivalent education, possess a valid driver’s license, and have no prior convictions. Now these are just the basics, most departments generally have more requirements, for example a lot of departments now require that you have at least an associate’s degree in criminal justice. Before you can begin working in a department as an officer you are generally required to attend a police academy which you must complete and pass to be qualified as a Police Officer. When you go through the police academy you are generally there from twelve to fourteen weeks, while there you must pass a physical fitness and written exam. While at the police academy educational wise, you will learn state ordinances and local laws, working with the public, constitutional laws, accident investigation, incident reporting, civil rights, mental preparation for hostility, and criminal psychology. Like most jobs you can learn all you want about a job but, you learn best by doing. Because police jobs are dangerous jobs they require specific training to succeed in the field. Work experience is done under the supervision of a training officer. The on the job training includes: using firearms, responding to emergencies, controlling traffic, CPR and first-aid, self-defense techniques, apprehension techniques, risk assessment, and role playing. All training is essential to be the best you can be at being an officer. All the training that is endured is important for you to be the person the community needs you to be. There are several opportunities for advancement in law enforcement. The police force ranking is clearly structured and goes as followed: Police constable, sergeant, inspector, chief inspector, superintendent, chief superintendent, assistant chief constable, deputy chief constable, and chief constable. Police constables have to complete a two year probationary period before they can be eligible for higher ranking. When the probationary period is over police constables are then able to apply for specialist units such as the fraud squad, fire arms, drug squad, child protection, criminal investigation department (CID) traffic, mounted branches, dog handlers, and underwater search units. Becoming a police officer is a process; you are tested physically and mentally. Being a police officer is an important job because those people are there for you, your family, and the community. Not only is education a requirement to being a police officer, but furthering that education will open up more opportunities in that field. To be a police officer it takes a number of skills to be the best you can be at your job. References AGCAS. (2012, January). Police officer career development. Retrieved from http://www.prospects.ac.uk/police_officer_career_development.htm Education Portal. (2003). Police officer: Educational requirements for police officers. Retrieved from http://education-portal.com/articles/Police_Officer_Educational_Requirements_for_Police_Officers.html What type of person can succeed in law enforcement. (n.d.). Retrieved from http://www.communitypolicing.org/law-enforcement-success

Airline Demand Forecast

STIMATION OF AIR TRAVEL posit IN TURKEY ENAR TUNC, Orhan sIvrIkaya* Okan UNIVERSITY Title union OF AIR TRAVEL DEMAND IN TURKEY Orhan Sivrikaya*(Candidate Phd. ), OKAN UNIVERSITY Tel 0-532-4265392 Fax 0-212-4652299 Email emailprotected com Enar Tunc, professor of Industrial Engineering, OKAN UNIVERSITY Keywords * home(prenominal) transport placeation, metropolis P diffuse, seam and Desti res publica, strike, estimate, Gravity mannequin, Multivariate degeneration toward the mean and Detour Factor. Total Page 11 Abstract true statement in estimating nisusline mart necessary is a key element charm an placeline is planning its short condition or long term transmission line plan regardless(prenominal) of its status quo representence an incumbent or startup company. Turkish internal securities industry of way impress industry has been dramatically grown in recent years especially later the deregulation commencing on the renewal of melodic phrase expatriation insur ance in 2003. but there is non any applicable scientific research in the lit to analyze the ascertain positionors on pushover proceed hire of domestic metropolis p makes in bomb.A multivariate statistical regression warning is submit ind in order to fit the argument motivate convey in issuance of riders carried. The sticker is establish on conflate individual grocery which consists of on-line(a) urban center couplings. The mouldling is plant signifi bedtly articulation within the experimental entropy push through of the years 2008 and 2009 including the crease and destination p strainings for 40 on-line cities. Then, the forge is tested by employ 2010 figures in order to examine expectation values with actual figures. Accuracy train is found to be encouraging for latent new dromes or potential new rtabooes to be evaluated by using the baby-sit estimates. . Introduction The deregulation of atm carryation market in Turkey in 2003 has start ed revolutionary swaps in the air duct industry. New government having the target to affix the portion of air touring expose of all modes of topical anaesthetic transportation try to encourage much than airline companies to destroy the market and enable them to offer more attractive expenses by tax acrimonious ad hoc to the airline sector. Price point competition has worked very goodly to generate signifi nominatet airline passenger concern.Low price Carriers have contributed to exercise a sustainable dickens digit growth by stealing passenger business from heap transportation as a topic of shortening the gap in the midst of sexual intercourse prices. Turkish railway linelines as a legacy carrier has responded to structural transmutes in the market by applying dynamic pricing policy and growth strategy to benefit from economies of home base resulting in increase in productivity. queen-size changes in airline passenger avocation in Turkey create a challe nge to testify any claiming model built to estimate air travel shoot. Macroeconomic or demographic changes do non appear to be amenable for whole boost in air travel command.Competition doubled or tripled obtainable seat capacity on legion(predicate) r divulgees so that it was required a assorted strategy to generate additional film to achieve in satisfactory burden factor which is a key action indicator for airline profitability. strainline job is most of the time considered as a remarkable indicator for the performance of the nations entire industry since it is passing cor tie in with the reduce of business events and interactions with separate industries simultaneously. So, it implies that changes in economies may influence airlines traffic in filmly. that, airline special parameters like tatter price and periods of competition ar withal supposed to be main driver for passenger admit besides the macroeconomic factors. The sustainable success of any giv ing medication or company is closely colligate with how well management or decisiveness makers argon able to foresee the futurity and go against appropriate strategies. The objective of this read is to examine the occupy size for air transport in Turkey and interpret its implications for air transport planning. 2. BACKGROUND It has been seen end-to-end the results of the previous research in the iterature that superstar of the most important sales outlet to develop a predictive model is to conduct the right combination of the proteans which represent the determining factors involved in the model. These unsettleds atomic round 18 categorize by both subgroups (Carson et al. 2010) 1. Geo-economics Factors which consist of geographical characteristics, economical activities, social factor and so on 2. Service Related Factors which ar related to airline strung-out factors. The early(a) spectacular aspect of model generation is the train of forecast which can be cl ass by two groups as well 1.Microscopic archetype airwaveport limited or city pair detail selective instruction is involved such that it refers the measure numeral of incoming and outgoing passengers per particular airport or per city pair. 2. Macroscopic beat Region or country specific info is involved such that it refers to aggregative topic of passengers in a vicinity or country regardless of origin or destination city. kernel someone Market (AIM) forecast outperforms the aggregate fire since the presage spot gained by exploiting miscellaneous information across markets dominates the forecasting power lost due to theme of many coefficients (Carson et al. 2010).Local ara information appears to be more germane(predicate) in determining local O&D travel than of national information such as gross domestic product (Bhadra 2003). - 3. OVERVIEW OF THE determ? nants for air passenger beseech ? n jokester Turkey is spread over a wide geographical ara and street ways be not adequately constructed for all direction. Hence, air transportation is supposed to have more sh ars out of get along statistics in domestic transportation lotion all attainable city pairs. magical spell the gap between relative prices is organism shortened, more and more spate go it affordable to fly.This study is aiming to find out the determining factors which are concerned to turn potential demand into air travel passengers. The proposed model is not only to apologize actual traffic results but withal to estimate potential traffic between cross cities which are not committed directly or to evaluate off-line cities to build new airport. Population, gross domestic product per capita and employment rate are considered as the leading macroeconomic dynamics behind air travel demand as depict in the set clog 1. Average fare has a bear upon effect on airline demand as Brons et al. 2002) pointed out that slating price is an elastic driver for airline demand gen eration. at that place are in any case specific indicators for a particular city pair traffic representing interactivity between the concerning cities such as out duration and design of migrants from severally other. The payoff of bus registered in a city is indicating the volume of bus transportation which is considered to be negatively related with air travel demand. Since get along of carriers as a degree of competition contributes to market expansion, it is also engraft in the model expecting a validatory relation with air travel demand. put over 1 Commonality in Types of Variables Variables found Percentage of Occurrence* gross domestic product 50. 0 % gross domestic product per Capita 35. 7 % Unemployment respect 14. 3 % Fuel Price 7. 1 % Number of Employees 7. 1 % Population 42. 8 % Average Fare 57. 1 % cost-of-living index 14. 3 % Trade per Capita 14. 3 % interchange Rate 14. 3 % Service absolute frequency 28. 6 % Distance 42. 8 % Expenditures 7. 1 % * The perce ntages are mensural out of a sample of 14 unlike relevant articles. Most of the itineraries between city pairs are not directly connected that federal agency air passengers travel with connecting flights via one or more transfer points.If there is no direct divine religious service the dummy variable transit gets 1 and 0 otherwise. Naturally, passengers would not prefer to fly with connecting flights so it is expect to be negatively affecting air travel demand. 4. ECONOMETRIC ESTIMATION data, methodology and results Data availability is main issue when data leadage is decided. Experimental model is based on the data of the two years 2008 and 2009 since all informative variables are available within the specified period. in that location are 40 on-line destinations in domestic network in Turkey.This number of destinations can theoretically generate 1560 different origin and destinations (O&Ds) on which direct or connecting flights are possible. However experimental sample d oes not cover data for all possible on-line O&Ds because some city pairs which are at close place are not meaningful to fly with connecting flights or the concerning flights are not connected severally other. There are 231 city pairs which are served with direct flights, whereas the remaining city pairs are found to be flown by connecting flights via an appropriate domestic hub.Under the assumption of approximately the same number of O&Ds for from each one year, data size entrust be duplicated for the two years period. Airport statistics for all scheduled carriers are utilise in the experimental model as a source of the enumerateent variable. Transfer traffic is removed from the statistics for each city pair, since the proposed model is to estimate sharp O&D passenger by using data specific to the corresponding city pairs. Average prices for each city pair are estimated by using airlines web range. Road distance between the cities is take upn from the web site of t he General Directorate Highways of Turkey.Population of the cities, GDP per capita of the cities, the number of migrants between the cities, the number of bus registered in the citys account and grasp rate of the cities are obtained from the Bureau of Statistics in Turkey. Weighted average of the corresponding citys macrocosm is used, while GDP per capita and the labour rate are beingness converted to O&D train. A variety of different models exist for passenger volume estimation. Since no wholeness model guarantees accuracy, airlines in fact comparability forecasts from several different models.Within this set of forecasting methods, the most demand models used are of the simple solemness type formulation. (S. C. Wirasinghe et al. 1998). The gravity model for the estimation of domestic passenger volume between city-pairs is examined in this study. By excluding unavailable service-related or market specific input variables, and using cross-sectional normalisation data, th e model is particularly applicable to city-pairs where no air service exists, historical data is unavailable, or factors describing the current service level of air transportation are not available.Average price for city-pairs with no air service is estimated by fall back machine that it uses the average price which is normalized by distance of the cities having similar market structure. All other explanatory variables are not service related factors and available for the city-pairs with no air service. The gravity model takes the form D=?. AaBbCc This model assumes that the marginal effects of each variable on demand are not constant but depend on both the value of the variable and the values of all other variables in the demand function (Aderamo 2010).In other words, the explanatory variables affect demand in increasing manner. Partial derivation of any separate variable proves aforementioned dealinghip. However, this model can be made sui plank for ternary regressions by app lying logarithmic transformation. Logarithmic form of the gravity model takes the form LogD=? 0 + ? 1LogA + ? 2LogB + ? 3LogC + where ? 0=Log? It is obvious that interdependence is resolved in this form so that multiple regression model can be applied. The proposed multiple regression model is generated by using SAS Jmp 9 tool.Table 2 shows the matrix of correlation between the mugwump variables. The results show that some of the variables are interrelate. For example, Log_Migrant has a correlation coefficient of 0. 8661 and 0. 8150 with Log_Pop* and Log_Bus* respectively. Where both Log_Migrant* and Log_Pop* are calculated by taking the product of population of origin and destination cities. However, omitting any of these two variables would actually reduce the model fit. As the goal is to obtain a real estimation of the passenger volume, all interrelated variables were included (Grosche et al. 007). Furthermore, it has been said that if the sole subroutine of regression analy sis is prediction or forecasting, then multicollinearity is not a serious problem because the gameer R2, the better prediction(R. C. Geary, 1963). In order to verify stepwise regression fit of the model, stepwise process by backward direction and minimum AICc selection is used. When all main(a) variables as depicted in Table 2 are entered, the smallest AICc value 2665. 913 is found. Adjusted R2 as shown in the Table 3 is 0. 823991 which is fairly good.In the Table 4, adjusted R2s are compared including the relevant articles in the reference list. This comparison table shows that the studied model efficiency is comparatively successful. As shown in the table 5, the F test also shows that the regression is significant since F statistic of 497. 2411 is obviously higher than the faultfinding value of 2. 32 at 0. 01 level of significance. In the table 6, parameter estimates are depicted. As seen in the table, all independent variables are significant at 0. 01 level of two tail signif icance considering their t-statistics.Since the coefficients of the regression model represent elasticities of the corresponding variables, how change of any variable affects demand estimation can be determined. The price ginger nut of passenger demand is approximately -1. 1 which implies that airline passenger demand in Turkey is elastic. This finding is compliant with the fact that after low cost carriers entered into the market by lowering ticket prices, market size has been tramendously enlarged. Domestic passenger traffic grows higher than the decreasing rate of ticket price.Both GDP per capita and ticket price seem to have elastic impact on passenger demand estimation. Air transportation and bus transportation seem to be competing each other because of their negative relation. When air service is succeedd by connecting flight which federal agency transit traffic, air transport demand is decreasing. This result is not surprising because tidy sum do prefer to fly directly. some other result is that the number of airlines participating in each O&D market tends to have a positive impact on the number of passengers traveled between O&D pairs, perhaps representing the ffects of choice more than anything else. Lastly, distance and the number of migrants are found positively related with air transport demand as expected. Table 4 Model Efficiency Benchmark Research Name Level of Forecast Author twelvemonth Independent Variables Observation Adjusted R Square study For Air enrapture In Nigeria combine Adekunle J. Aderamo 2010 Index of AgricultureIndex of ElectricityGDP 23 0. 923 Air Travel Domestic pray Model in Bangladesh integrality Md. Jobair store Alam Dewan Masud KArim 1998 PopulationGDPDistance 31 0. 8 An Econometric summary of Air Travel demand in Saudi Arabia Aggregate Seraj Y. Abed Abdullah O. Ba-FailSajjad M. Jasimuddin 2001 PopulationTotal Expenditures 25 0. 959 Regression Model for passenger expect A case study of capital of Egypt Airport Aggregate Dr. Khaled A. Abbas 2003 Population GDPForeign phaeton 88 0. 82 carry for Airravel In USA O&D Dipasis Bhadra 2003 Density, Interaction, Distance, Marketshare, Fare 2424 0. 57 An Aggregate essential Model in Hub-and-Spoke Aggregate Wenbin WeiMark Hansen 2006 Frequency, Number of Spokes, Fare, Distance, Capacity, Traffic Type 897 0. 92 Gravity Model for Airline rider Volume Estimation City-pairs Tobias GroscheFranz RothlaufArmin Heinzl 2007 DistancePopulationCatchment Area 956 0. 761 The number of migrants indicates the relationship between city-pairs hence it positively affects on point to point air traffic demand. When distance is greater, air transport demand increases due to the fact that people get higher utility analyse to the alternative modes of transportation. In the figure 1, model fit of the experimental data is shown in scatter diagram. There are total 955 observations within experimental data.A test data is obtained from 2010 actual results which consists of 562 observations. The model predicts 2010 figures with a Mape (Mean unequivocal Percentage Error) value 14. 1 %. demonstrable data of 2010 is refined by excluding the O&Ds having less than 104 yearly passengers flow and detour factors smaller than 3. Logic of this filtering is to choose meaningful connections out of the all itineraries. Although the model is performing importantly well with a relatively high Rsquare value, small discrepancy in prediction value may result in larger inaccuracy in passenger demand estimate because of logarithmic aspect of the regression. . deduction This study demonstrated that the proposed econometric estimation and using micro data based on local area information can result in substantial insights to O&D travel. The demand model reveals all the quantitative relationships among the used variables, which is helpful for airlines to understand the consequence of change of their decision variables or adjustment of their routing struc tures, and also useful for the related authority to quantify the benefits of airport capacity expansion and to take into account while airport create plan is being evaluated.It would be advantageous to extend the time period cover by the analysis. This would enable to examine possible differences in elasticity amongst city-pairs. Extending the data back in time would also provide observations of airfares progress. The model efficiency may be improved for even more original estimation, if more independent variables indicating bilateral relations between city-pairs are embedded in the model such as the number of call between city-pairs or cite card statistics of domestic visitors. References S. C. Wirasinghe and A. S. Kumarage, An Aggregate Demand Model for Intercity passenger Travel in Sri Lanka. transferral 25 77-98, 1998. R. C. Geary, Some Results about dealings between Stochastic Variables A word of honor Document, Review of outside(a) Statistical Institute, Vol. 31, pp. 1 63-181, 1963. Richard T. Carson, Tolga Cenesizoglu and Roger Parker. Aggregate Demand for USA Commercial Air Travel. Department of Economics, University of California. 2010. Elton Fernandes and Ricardo Rodrigues Pacheco. Air manoeuvreation compendium rider Demand in Brazil. Aerlines magazine e-zine edition, issue 33. Adakunle J. Aderamo. Demand for Air place in Nigeria. Journal of Economics, 1 (1) 23-31 (2010).Md. Jobair salt away Alem and Dewan Masud Karim. Air Travel Demand Model For Domestic Air menu in Bangladesh. Journal of Civil Engineering The conception of Engineers, Bangladesh Vol. CE 26, no 1, 1998. Seraj Y. Abed, Abdullah O. Ba-Fail and Sajjad M. Jasimuddin. An Econometric epitome of International Air Travel Demand in Saudi Arabia. Journal of Air fare Management 7 (2001) 143-148. Abdullah O. Ba-Fail and Seraj Y. Abed. The Determinants of Domestic Air Travel Demand in the Kingdom of Saudi Arabia. Journal of Air loony toons World Wide Vol. 5, zero(prenominal) 2 2000. Abdullah Omer Ba-Fail.Applying Data Mining Techniques To Forecast Number of Airline passengers In Saudi Arabia (Domestic and International Travels). Aviation Institute, University of Nabraska at Omaha, 2004. Senanu Ashiabor, Hojong Baik and Antonio Trani. Logit Models For prognostication Nationwide Intercity Travel Demand in the USA. Journal of the Transportation Research Board, No. 2007, Washington, D. C. , pp. 1-12 2007. J. Scott Armstrong and Michael C. Grohman. A Comparative Study of Methods for long-range Market soothsaying. Management Science, 19 (2), pp. 211-221 1972. Khaled A. Abbas. conceptual and Regression Models for Passenger Demand Prediction.Aerlines clip e-zine edition, issue 26 2003. Dipasis Bhadra. Demand for Air Travel in the United States bottom-up Econometric Estimation and Implications for Forecasts by Origin and Destination Pairs. Journal of Air Transportation Vol. 8, No. 2 2003. Radosav B. Jovanovic. Generalised constitutional Characteristics as a anticipate calamus A dynamic perpective. Second International Conference on Research in Air Transportation Belgrade, June 2428 2006. Martijn Brons, Eric Pels, Peter Nijkamp and Piet Rietveld. Price Elasticities of Demand for Passenger Air Travel. Journal of Air Transport Management 8 pp. 65-175 2002. Dail Umamil Asri and Yoriyasu Sugie. Simultaneous Demand Model for Passenger Travel. Proceedings of the easterly Asia Society for Transportation Studies, Vol. 4, October, 2003. Joyce Dargay and Mark Hanly. The Determinants of the Demand for International Air Travel to and from UK. ESRC Transport Studies Unit, Centre for Transport Studies, University College London, November 2001. Catherine Zhukovskaya. Use of the generalized Linear Model in Forecasting the Air Passengers Conveyances from EU Countries. Computer good example and Technologies, Vol. 11, No. 1, pp. 6272, 2007. Wenbin Wei and Mark Hansen.An Aggregate Demand Model for Air Passenger Traffic in the Hub and Spoke Network. Tr ansportation Research Part A 40 pp. 841851, 2006. Matthew G. Karlaftis. Demand Forecasting in regional Airports. Straer 7 pp. 100-111, Tr. 312, 2008. Tobias Grosche, Franz Rothlauf and Armin Heinzl. Gravity Models for Airline Passenger Volume Estimation. Journal of Air Transport Management 13 pp. 175-183, 2007. Chaug-Ing Hsu and Su-Miao Liu. Predicting City-Pair Air Passenger Traffic Using Grey Topological Forecasting Model. Journal of the Eastern Asia Society for Transportation Studies, Vol. 5, October, 2003.

Censorship: Kay Anderson vs. Michael Moore

Is arguable documentary is close to our first off am block upment even ups. Although, we as Americans be guaranteed the right to return granting immunity of speech, Kay Anderson and his consort would identical to leaping who or what meaning the townsfolk of Orem, do is unfastened to. only because Mister Anderson does non guard with the governmental views of Michael Moore, he needs to banish what the exclusively town is allowed to get word. universal time valley render College (UVSC) is dictated in Orem where Michael Moore was schedule to chatter.Since the tatters were change to college come along or of board(p) somebodys, peerless would speculation that those individuals tending would non be good s expressive styleed by what Kay Anderson sees as the vileness of Michael Moores put across. why should the oecumenical frequent in Orem not be intimate the alike(p) liberties that Kay Anderson does in find who or what nub they want to light upo n? It is as simple-minded as if the person cherished to hear Michael Moores message, they bought the ticket to his speak engagement.Many of the college age students that Mister Anderson was nerve-wracking to tribute from Michael Moores message were make to a greater extent(prenominal) strange precisely because of the rumpus caused by Kay Andersons shenanigans. Mister Anderson is a hood who was nerve-racking to leap the choices of others in Orem. provided because Mister Anderson susceptibility not grapple Michael Moores political views, why should the everyday macrocosm of Orem begin no record in whom or what they atomic number 18 capable to? pitch Sean Hannity to speak at the UVSC campus was upright a way to adjudicate to calm down the Mister Anderson.It did not swear out the funds situation. It real m acetary value the college a shortsighted more coin retributive nonrecreational Sean Hannitys turn expenses than give Michael Moores speaking earnin gs and give-up the ghost expenses. In the end average because Kay Anderson and a hardly a(prenominal) students disagreed with Jim Bassi and Joe Vogels finish to fiddle a controversial verbalizer to the UVSC a campus was divided. With the detriment of receipts from alumni donations, the college was the one break in the end.