Summary of The forces that turned Baba around Essay Example for Free

Summary of The forces that turned Baba around Essay The history is about the 16-year-old Babatonte, or Baba as his friends call him. He went at St Aloysius college in Highgate. He havent had an easy childhood and that has effected his education. When he was 12, he had been suspended from school about 5 times. Every time he was suspended from school, he only saw it as holyday. Baba describes him selves as a bad boy there vandalising school property, truanting and getting into figths. At the first year of college, Baba had alot of problems. But later on he went to his second year at college. His plan for the future are being an actor. He has just been in a movie at the college that went out very good. The students are spending 2 days a week learning how to, climb a rock, sail a canoe and camping. And they also have been taught first aid, how to cook and carpentry. In the tekst about Baba and in tekst two Coming of the ropes, is the attitude possitive. Childrens with problems cant be pushed, like every other childrens, but instead they need help. They need to get some self-confidense. In tekst three, called The single bullet that broke a communitys heart, and in tekst four, called Out on the streets, the kids are scared too, the two teksts have a bad attitude, but they mean that young children can be good if they just have some places to be and to chill out, instead of doing it at public places. Comment on the statement Boys are useing more violence than word, rather than girls who are useing more words than violence. Girls are generally better to express their feelings and talk about their problems. Boys cant express their feelings as good as girls, and they are getting a feeling, that they are been defeated, if they are talking about their feelings. Some of the things that could be keeping teenagers out trouble is if the young people maybe has a bad childhood, I think something there could help them, would be if there were some adults there could help them from they were kids, then there would? be any kind of troubles in their youth. Another thing there could also help the teenagers out of trouble could be if there were several after school centers. If there were several after school centers, then the young peoble/teenagers had somewhere to go instead of being on the streets and public places. The last thing I can imagine that could help, are if their weekday were getting a little bit diffrent, so they dont have to sit and make schoolwork all day, but maybe got some interest in for example sport.

Factors Affecting Postharvest Quality of Fresh Fruits

Factors Affecting Postharvest Quality of Fresh Fruits A ripened ovary of a flower together with any accessory part associated with, is referred to as fruit (Lewis Robert 2002). In non-technical usage the term fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state, for example apples, oranges, grapes, strawberries and bananas (Mauseth James, 2003). Fresh fruits and vegetables are living tissues which undergo continuous changes after harvest. Some of these changes are desirable, but from consumers point of view most of them are undesirable. It is not possible to stop the postharvest changes in fresh produce, but they can be retarded within certain limits (Kader, 2002). There are several atmospheric factors which affect the postharvest life of fresh fruits. Climatic conditions, specially temperature and light have a significant effect on the nutritional quality of fresh fruits and vegetables (Kader, 2002). FACTORS AFFECTING THE POSTHARVEST LIFE OF FRUIT RESPIRATION Respiration is the process by which stored organic materials are broken down into simple end products with a release of energy. During this process oxygen (O2) is consumed while carbon dioxide (CO2) is produced. All living organisms must carry out respiration at all times (Kader, 2002). Respiration Metabolism Even after the harvest, fruits and vegetables remain as living organs. Like all living tissues, harvested produce continues to respire throughout its postharvest life. The main purpose of respiration is to maintain sufficient supply of adenosine triphosphate (ATP).The process of aerobic respiration involves the regeneration of ATP from ADP (adenosine diphosphate) and Pi (inorganic phosphate) with the release of CO2 and H2O. In case of hexose sugar the overall reaction can be written as (Kader Saltveit, 2003) The different components in this reaction have different sources of destinations. The 1 mole of glucose (180g) can come from stored simple sugars (glucose, sucrose) or complex polysaccharides (starch). The 6 moles of O2 (192g) used to oxydize the 1 mole of glucose diffuses into the tissue from the surrounding atmosphere, while the 6 mole of CO2 (264g) diffuses out of the tissue. The 6 mole of water (108g) produced is simply incorporated into the aqueous solution of the cell.(Kader Saltveit, 2003) Aerobic respiration involeves a series of three reactions, each of which is catalyzed by a number of specific enzymes that either (i) add a phosphate group to a molecule, (ii) rearrange the molecule, or (iii) break down the molecule to a simpler one ((Biale, 1960);(Davies, 1980)). The three interconnected metabolic pathways are glycolysis, the tricarboxylic acid (TCA) and the electron transport system. Glycolysis The breakdown of glucose occurs in the cytoplasm, which produce two molecules of pyruvate. 10 different sequential reactions are catalysed by one enzyme. Phosphofructokinase (PFK) is the main enzyme in Glycolysis, which cleaves fructose 1, 6-diphosphate into two triose phosphate molecules. By controlling PFK activity of Glycolysis, cell can control their rate of energy production. ATP is used as a negative feedback inhibitor to control the activity of PFK (Davies, 1980). Besides pyruvate, Glycolysis also produces two molecules of ATP and two molecule of NADH (reduced nicotinamide adenine dinucleotide) from the breakdown of each molecule of glucose. Tricarboxylic Acid (TCA) Cycle The TCA cycle occur in mitochondrial matrix, involves in the breakdown of pyruvate into CO2 in nine sequential enzymatic reactions. Pyruvate is decarboxylated to form acetate, which condenses with a co enzyme to form Acetyl CoA. This compound then enters the cycle by condensation with oxaloacetate to form citric acid. Citric acid has three carboxyl groups, from which the cycle derives its name (Kader Saltveit, 2003). Through a series of seven successive rearrangements, oxidations and decarboxylations, citric acid is converted into oxaloacetate, which is then ready to accept another acetyl CoA molecule. The TCA cycle also produces one molecule of FADH2 (reduced flavin adenine dinucleotide) and four molecules of NADH for each molecule of pyruvate metabolism. Electron Transport System The electron transport system occurs in the cristae of mitochondria, results in the production of ATP from the FADH2 and NADH. The energy produced is more than the cellular process requirement. In a series of reactions, one NADH molecule produces three ATP molecules and one FADH2 molecule produces two ATP molecules, but the exact number of ATP produced during electron transport depends not only on the energy of NADH and FADH2 but also on the chemical environment within the cell and mitochondria. In the absence of O2, NADH and FADH2 accumulates, the TCA cycle stops and Glycolysis become the only source of ATP production. In anaerobic respiration hexose sugar is converted into alcohol and CO2 in the absence of O2. Pyruvate produced in Glycolysis is decarboxylated by the enzyme pyruvate carboxylase to form CO2 and acetaldehyde. The acetaldehyde is converted by the enzyme alcohol dehydrogenase to ethanol with regeneration of NAD+. Two moles of ATP and 21 kcal of heat energy are produced in anaerobic respiration (alcoholic fermentation) from each molecule of glucose (Kader Saltveit, 2003). Respiration Quotient (RQ) The respiration quotient (RQ) determines the amount of substrates utilized in the respiration process. In other words RQ is the ratio of CO2 produced to O2 consumed measured in mole or volumes. In the aerobic respiration of carbohydrates the RQ is near 1, while is 1 for organic acids. Very high RQ values usually indicate anaerobic respiration in those tissues which produce ethanol. GAS EXCHANGE Barrier to Diffusion Gas exchange between a plant organ and its environment follows Ficks first law of diffusion. The sequential steps are (i) diffusion in the gas phase through the dermal system (i.e. cuticle, epidermis, stomata etc.); (ii) diffusion in the gas phase between the intercellular spaces; (iii) exchange of gases between the intercellular atmosphere and the cellular solution (cell sap) and (iv) diffusion in solution within the cell to centres of O2 consumption and from centers of CO2 production. This exchange is a function of the resistance of the dermal system to gas diffusion, the surface area across which diffusion can take place etc. CO2 produced within each cell will raise the local concentration and this will drive diffusion of CO2 outward, toward the lower concentration near the cell-wall surface adjacent to the intercellular space. Diffusion of CO2 into intercellular space continues toward regions of lower concentration until it reaches the intercellular space below the dermal system. From there, CO2 moves through the cuticle or openings in the commoditys surface to the air (Burton, 1982). Movement of O2 within plant tissue is in a reverse but similar process to that mentioned above for CO2. In senescent tissue, O2 diffusion may be slowed down if the intercellular spaces become filled with cellular solution that anaerobic conditions develop within tissues. The rate of gas movement depends on the properties of gas molecule and the physical properties of the barriers (thickness, density etc.). Solubility and diffusivity of each gas are important for its diffusion across barrier. CO2 moves more readily than O2, while diffusion rate of C2H4 and CO2 are similar. Internal concentration of CO2 and O2 in plant organs depend upon the maturity stage at harvest, the current organ temperature, the composition of external atmosphere and any additional barrier. Maturity stage influences the dermal system that effects gas diffusion. Increased temperature results raised rate of respiration as a result internal CO2 level increases as the O2 level decreases. If all other factors are held constant and the movement in the gas concentrations is the driving force for diffusion, then the concentration of O2 and CO2 within the tissue will fluctuate according to the fluctuation in the external atmosphere. Methods to Alter rates of Gas Exchange There are three types of barriers to gas exchange that affect the postharvest handling of fresh produce (Fig. 1). These are (i) the structure of the dermal system such as thickness of cuticle, number and distribution of stomata and breaks in epidermis etc. Resistance to gas diffusion can be increased by adding barrier such as wax coating or covering produce with polymeric films. (ii) The package in which the commodity is shipped can be additional barrier to gas diffusion. (iii) The degree of gas tightness of the transit vehicle or storage room will also affect gas exchange with outside air. Schematic model of a commodity and its environment with three levels of gas exchange: B1=structure of dermal system and added barriers (waxing and film wrapping), B2= Permeability of package to gas diffusion, and B3 = gas tightness of the storage room Source: (Kader Saltveit, 2003) Ficks first law of diffusion states that the movement or flux of a gas in or out of a plant tissue depends on the concentration gradient across the barrier involved, the surface area of the barrier and the resistance of the barrier to the diffusion. Ficks law can be written as follows: J = A. ΆC/R Where J =Total flux of gas to be diffused (cm3.s-1) ΆC= Concentration gradient across the barrier A=the surface area of the barrier R= Resistance to diffusion If the production or consumption rate of the gas by the organ and the concentration of the gas in the internal and external atmosphere is known, then the resistance is calculated as follows: R = Concentration gradient/ Production or consumption rate Different harvested fruits and vegetables have different rates of respiration; some respire at a faster rate (more perishable), while some respire at a relatively slow rate (less perishable vegetables) (Table 1). Table 1: Classification of Sample Horticultural Commodities According to Respiration Rates (Wilson, 1999). Respiration Rates Types of Fruits and Vegetables Very Low Dried fruit and nuts Low Apples, garlic, grapes, onions, potatoes (mature), sweet potatoes Moderate Apricots, cabbages, carrots, figs (fresh), lettuce, nectarines, peaches, pears, peppers, plums, potatoes (immature), tomatoes High Artichokes, Brussels sprouts, cut flowers, green onions, snap beans Extremely High Asparagus, broccoli, mushrooms, peas, sweet corn The process of respiration is very important during ripening of fruit. In general there is an inverse relation between the rate of respiration and the postharvest life of fruit. Postharvest produce are classified according to their respiration rate as climacteric or non- climacteric. The rate of respiration increases in climacteric fruits during ripening while non-climacteric fruit shows no change in their low CO2 and ethylene production rates during ripening (Kader, 2002). If prevention or decrease in respiration is achieved, this will prolong post-harvest storage life. Ethylene causes the increase in respiration, so decreasing ethylene is also a strategy used to increase post-harvest storage life. Factors affecting respiration rate Environmental Factors Temperature Temperature is important environmental factor in the postharvest life of fresh produce due to its outstanding effect on rates of biological reactions, including respiration. Within the physiological temperature range, the velocity of biological reaction increases two to threefold for every 10  °C rise in temperature (Vant Hoff rule). The ratio of reaction rates at two dissimilar temperatures is called the temperature coefficient (Q10) if the interval between the two temperatures is 10oC. If the temperature interval of Q10 is not exactly 10o C then it can be determined by the following equation: Q10 = (R2/ R1) 10/T2-T1 Where R2 = rate of respiration at T2 R1 = rate of respiration at T1 T1 and T2 = temperature in  °C Scientists have found that Q10 is not constant for most biological processes over a wide range of physiological temperatures. Usually Q10 ranges from 1 to 5, although higher value may occur. For most biological reaction the Q10 is between 2 and 3 for temperature between 10 to 30  °C that means the reaction rate will be double or triple with every 10  °C increase. O2 and CO2 Concentration Practically, respiration can be controlled by either increasing carbon dioxide or decreasing oxygen. Decrease in oxygen near to zero is not desirable, though the O2 concentration reduces below that in air (20.9%) and especially below 10%, a significant reduction in respiration rate is observed (Gorny, 2001). However when O2 concentration drops to less than 2 %, anaerobic respiration rate become predominant and CO2 production increases. (Figure 2) (Kader Saltveit, 2003). Ethylene Concentration Exposure of climacteric tissues during their pre-climacteric stage to ethylene raises the rate of respiration. Once the respiration rise has begun, the endogenous rate of ethylene production increases and the internal ethylene concentration also increases, reaching levels that saturate its biological activity. However, unlike the case in climacteric tissues in non-climacteric tissues endogenous ethylene production remains unaffected (Kader Saltveit, 2003). Internal factors Type of Commodity Fruits and vegetables vary greatly in their respiration rate (Table. 1). Differences among plant parts and in the nature of their surface coatings (e.g. cuticle thickness, stomata, lenticels) influence their rate of diffusion characteristic and consequently their respiration rates. Stage of development at Harvest The respiration rate is usually high at early stages of development and decreases as plant organs mature. Thus fruits and vegetables harvested during the active growth phase have high respiration rates. Chemical Composition Respiration rate decreases with a decrease in water content of the tissue. The value of Respiration Quotient (RQ) is usually controlled by the rate of utilization of carbohydrates, proteins, lipids etc. ETHYLENE PRODUCTION Ethylene (C2H4) is a gaseous hormone produced from bacteria, fungi and all parts of higher plants such as shoots, flowers, seeds, leaves, roots, and fruits (Pech et al., 2003). It is a flammable and colourless gaseous compound (Arshad Frankenberger, 2002). Being a ripening hormone ethylene play a very important role in the postharvest life of many horticultural products, like increasing senescence speed and reducing shelf life but beneficially it improves the quality of the fruit and vegetables by manipulating uniform ripening process (Reid, 2002, p. 149). Because of the enormous influence of ethylene on the physiological development and postharvest life of fruits and vegetables, its biosynthesis, action, and control have been intensively investigated (Reid, 2002; Pech et al., 2003). The biosynthetic process of ethylene is usually completed in three major steps. The ethylene biosynthetic pathway is given in the figure 3. Step I: The biosynthesis of ethylene hormone is started by the conversion of Methionine (MET) to S-adenosyl-L-methionine (SAM) by the enzyme methionine adenosyltransferase (Pech et al., 2003). However, methionine adenosyltransferase is thought to consider as a rate limiting enzyme in ethylene biosynthesis because formation of SAM depends on the activity of this enzyme and SAM levels may indeed regulate ethylene production. Therefore, the sensitivity or importance of methionine adenosyltransferase to SAM implies that this enzyme may play a regulatory role in ethylene biosynthesis (Arshad Frankenberger, 2002, p. 13). Step II: SAM is consequently converted to 1-aminocyclopropane-1-carboxylic-acid (ACC) by a pyridoxal enzyme ACC synthase (ACS) (Figure 1). Actually, before the discovery of ACC, as intermediate, immediate precursor in MET dependent ethylene production process, the ethylene biosynthetic pathway was intangible (Arshad Frankenberger, 2002, pp. 11-50). The conversion of SAM to ACC by ACS is another rate-limiting step in the biosynthetic pathway of ethylene. ACS is a cytosolic enzyme (found in the cytoplasm of plants) (Paliyath Murr, 2008b) and its activity is strongly inhibited by aminoethoxyvinylglycine (AVG) (a competitive inhibitor) and aminoisobutyric acid (AIB) (an inhibitor of pyridoxal phosphate-mediated enzyme reactions) (Arshad Frankenberger, 2002, pp. 11-50). Moreover, the activity of ACC synthase is also influenced by factors such as fruit ripening, senescence, auxin levels, physical stresses, and chilling injury. The synthesis of this enzyme increases with an increase in the level of auxins, indole acetic acid (IAA) and cytokinins (Wills et al., 1998, p. 42). Step III: At last the ACC converts into ethylene by the action of ACC oxidase (known as ethylene forming enzyme or EFE) (Arshad Frankenberger, 2002, pp. 11-50; Pech et al., 2003). However, ACC oxidase is a bi-substrate enzyme as it requires both oxygen and ACC. Moreover, this enzyme also requires Fe2+, ascorbate and CO2 for its activity. Activity of ACC oxidase is inhibited by cobalt ions, and temperatures higher that 35oC (Wills et al., 1998, p. 42). The sub cellular position of ACC oxidase is still a point of controversy because there is a large number of data is available showing that this enzyme is associated with plasma-membrane or with apoplast or tonoplast. The activity of this enzyme (ACC oxidase) has been studied in many horticultural crops like melon, avocado, apple, winter squash, pear and banana. The activity of ACC oxidase is not highly regulated as ACS. It is constituted in most  vegetative tissues and it is induced during fruit ripening, wounding, senescence and fungal  eli citors (Arshad Frankenberger, 2002, pp. 11-50). In fruits and vegetables several metabolic reactions starts after harvesting. In most cases, an increase in biosynthesis of gaseous hormone like ethylene serves as the physiological indication for the ripening process. During ripening process, in some fruits large amount of ethylene is produced which is usually referred as autocatalytic ethylene production response. However, fruits are divided into two main categories on the basis of ethylene production, i.e. climacteric (those produce large amount of ethylene) and non-climacteric fruits (those produce smaller amount of ethylene). In climacteric fruits like apple, pear, banana, tomato and avocado, ethylene production usually ranges from 30-500 ppm/(kgh) during ripening. While non-climacteric fruits like orange, lemon, strawberry and pineapple, produce 0.1-0.5ppm/(kgh) of ethylene (Paliyath Murr, 2008) (Table 2). Therefore application of even a very low concentration of ethylene (0.1-1.0 ÃŽÂ ¼L/L) is sufficient enough to accelerat e full ripening of climacteric fruits; however, the magnitude of the climacteric rise is not dependent on the amount of ethylene treatment. On the contrary, application of ethylene causes a temporary rise in the rate of respiration of non-climacteric fruits and the degree of increase depend upon the amount of ethylene (Wills et al., 1998). Moreover, the difference in the respiratory patterns of climacteric and non-climacteric fruits is associated with the different behaviour in terms of the production and response to ethylene gas (Burton, 1982). The increase in respiration, as influenced by ethylene application, may happen several times in non-climacteric fruits, but only once in climacteric fruits (Wills et al., 1998). Indeed, ethylene is produced by all parts of the plant but the magnitude of ethylene production varies from organ to organ and also depends on the stage and type of growth and developmental process. In fact, recent ethylene based research findings have increased the understanding of biosynthetic pathways and enzymes involved in ethylene production, as well as the development of several ways to manipulate ethylene production e.g. by genetic alteration of plants (Arshad Frankenberger, 2002). Ethylene is produced by various plant parts growing under normal conditions however, any kind of biological, chemical or physical stress (e.g. wounding) strongly promotes endogenous ethylene synthesis by plants. Among stress induced ethylene production, pre-harvest deficit irrigation is one of the most important factor causing higher ethylene production rates in fruits like avocado (Adato Gazit, 1974) and tomato (Pulupol et al., 1996). REGULATION OF ETHYLENE BIOSYNTHESIS In plants, ethylene itself stimulates the ability of the tissue to convert ACC into ethylene, which is also regarded as phenomenon of auto-regulation. In ripening fruits, regulation of ethylene biosynthesis is a characteristic feature and is triggered by the exposure to exogenous ethylene by the activation of ACC synthase and/or ACC oxidase (Arshad Frankenberger, 2002, pp. 25-27). On the other hand, sometimes ethylene inhibits its own synthesis, as negative feedback has already been recognised in a number of fruits and vegetable tissues. In such cases, exogenous ethylene significantly inhibits the production of endogenous ethylene, induced by ripening, wounding and/or treatment with auxins. Moreover, this auto inhibitory effect seems more directed towards limited availability of ACC in the presence of AVG, an inhibitor of ACC synthase (Arshad Frankenberger, 2002, pp. 25-27). Scientists have also revealed that the inhibition or negative regulation of ethylene synthesis is the result of activity of a gene, E8 whose expression leads to the inhibition of ethylene production in tomatoes (Arshad Frankenberger, 2002, pp. 25-27). MECHANISM OF ACTION The response of ethylene action can be classified into two categories namely concentration response and sensitivity response. The concentration response involves the changes in concentration of cellular ethylene while the sensitive response involves the increase in tissue sensitivity to ethylene. Moreover, both of these responses involve the binding of ethylene to some components of the cell to mediate the physiological effects (Arshad Frankenberger, 2002, pp. 28-36). Wills et al. (1998, pp. 42-45) likewise explained that plant hormones control the physiological processes by binding to specific plant or fruit receptor sites, which trigger the succession of events leading to visible responses. In the absence of ethylene, these receptor sites are active, allowing the growth of plant and fruit to proceed. During fruit ripening, ethylene is produced naturally or, if it is artificially introduced in a ripening room, it binds with the receptor and inactivates it, resulting in a series of events like ripening or healing of injuries in plant organs. Ethylene action can be controlled through modification of the amount of receptors or through disruption of the binding of ethylene to its receptors. Binding of ethylene is believed to be reversible at a site which contains metal like copper, zinc, or iron (Burg Burg, 1965, as cited in Burton, 1982). The affinity of receptor for ethylene is high in the presence of oxygen and decreases with carbon dioxide. Changes in the pattern of ethylene production rates and the internal concentrations of ethylene associated with the onset of ripening have been studied in various climacteric fruits. For instance, tomato and honeydew melon exhibited a rise in ethylene concentration prior to the onset of ripening, determined as the initial increase in respiration rate. On the other hand, apple and mango did not show any increase in ethylene concentration before the increase in respiration (Wills et al., 1998, pp. 42-45). Ripening has been associated with senescence as it leads to the breakdown of the cellular integrity of the tissue. It is part of the genetically programmed phase in the development of plant tissue with altered nucleic acid and protein synthesis occurring during the onset of the respiratory climacteric resulting in new or enhanced biochemical reactions operating in a coordinated manner (Wills et al., 2007, p. 40). These concepts confirm the known degradative and synthetic capacities of fruit during the ripening process. The ability of ethylene hormone to initiate biochemical and physiological events leads to the theory that ethylene action is regulated at the level of gene expression (Pech et al., 2003; Wills et al., 1998, pp. 45-46). TRANSPIRATION/ WATER LOSS Plants depend more on the availability of water than any other single environmental factor (Kramer and Boyer, 1995). Water loss is very important in determining the shelf life and quality of harvested plant organs. As long as the harvested produce retains water, it remains fresh. Transpiration is one of the main processes that affect postharvest life of the fruit (Ben-Yehoshua Rodov, 2003) Most fresh produce contains from 65 to 95 percent water when harvested. Within growing plants there is a constant flow of water. Fresh produce continues to lose water after harvest, but contrary to the growing plant it cannot replace lost water from the soil and so must use up its water content remaining at harvest (Gustavo et al., 2003). This loss of water from fresh produce after harvest is a serious problem, causing shrinkage and loss of weight. When the harvested produce loses 5 or 10 percent of its fresh weight, it begins to wilt and soon becomes unusable. To extend the usable life of produce, its rate of water loss must be as low as possible (Wilson et al., 1995). Although temperature is the prime concern in the storage of fruits and vegetables, relative humidity is also important. The relative humidity of the storage unit directly affects water loss in produce. Water loss means salable weight loss and reduced profit (Wilson et al., 1995). Transpiration of fresh fruits is a mass transfer process in which water vapor moves from surface of the plant organ to the surrounding air. Ficks law of mass transfer explains this process as follows: J = (Pi-Pa) At / (RDT)r Where Pi and Pa are the partial gas pressures in intercellular spaces and in the ambient atmosphere respectively; At is surface area of fruit; RD is the gas constant per unit mass; T is the absolute temperature; r is the resistance; and J is the gas flux. According to Ficks law, the movement of any gas in or out of the plant tissue is directly proportion to the partial pressure gradient (Pi-Pa) across the barrier involved and the surface area of the barrier and is inversely proportion to the barrier to diffusion. Therefore the driving force of transpiration is the difference of water vapor pressure (WVP) between the tissue and the surrounding air. While the water vapor pressure deficit (VPD) of the air is difference between the WVP of air and that of saturated air at the same temperature. Relative Humidity is the most popular term for expressing the water content of air. It can be defined as the ration of actual WVP in the air to the saturation WVP at a given temperature. Water loss depends on the difference between the water vapour pressure inside the fruit and the pressure of water vapour in the air. To control water loss in fresh produce as low as possible, it must be kept in a moist atmosphere. Air movement also plays a vital role in the water loss from the fresh produce. Water loss is directly proportion to the air movement in the surrounding. Though air movement through produce is also indispensable to remove the heat of respiration, but the rate of movement must be kept as low as possible (Gustavo et al., 2003). ROUTES OF WATER TRANSMISSION As the harvested fruits and vegetables are detached from plant, the xylem vessels are blocked with air and their operation is stopped (Burton, 1982). Therefore, water has to use different routes to move through the tissue. Following are the major potential pathways for water movement in harvested produce. Symplast The cytoplasm of connected cells is interconnected by plasmodesmata, filled with protoplasm and lined with the plasmalemma. Therefore symplast is formed throughout the interior of a plant organ. Water and dissolved solutes move through the symplast system from cell to cell by diffusion (Ben-Yehoshua Rodov, 2003). Apoplast The cell wall surrounding symplast also form a continuous system, termed as apoplast. The apoplas provide an alternative avenue for liquid water movement by hydrostatic pressure through the interfibrillar spaces in the cell wall (Woods, 1990). Intercellular Atmosphere The plant also contains a system of intercellular gas-filled spaces that form a continuous network and serve as main pathway for O2 and CO2 transport. This field of air space provide adequate gas exchange in bulky organs (Ben-Yehoshua.S, 1969). MAJOR EVAPORATION SITE: COMMODITY SURFACE There are three major routes for moisture loss from harvested commodities to the atmosphere: (a) through outer layer that forms a surface for evaporation (cuticle and epicuticle wax; periderm) resistance for water movement through (b) the apertures in the surface connecting the internal and external atmosphere (stomata, lenticels) and (c) through the stem scars or pedicel. Cuticle and Epicuticular wax This layer, which lines all interfaces between the plant and the atmosphere, protects the plant from its relative dry environment. Resistance to water movement is derived from cuticular layer (Ben- Yehoshua, 1969; (Burg Burg, 2006). The cuticle cosntains a matrix of cellulose, polyuronic acids, proteins and phenolic compounds. These are combined with variation of amount of waxes embedded over its surface (Kolattukudy, 1980). Permiability to water usually depends more on amount of waxes than on the thickness of cuticle (Kramer Boyer, 1995). Periderm Periderm is a corky peripheral tissue. This tissue consists of several layers of cells that become corky as a result of deposition of waxes on their cell walls, and they lose their living contents. The periderm is not readily permeable to water and is permeable to gases only through lenticular pores, which replace the stomata of the original epidermis. About 97% of the total water lost from the potato tubers migrates through cell walls to the periderm, where it evaporates (Burton, 1982). Trichomes and Hairs Unicellular or multicellular projections develop on the epidermis of all parts of plants. Their exact function is still vague, but they are considered to reduce water loss (Cutter, 1976). The presence of trichomes can decrease the driving force of transpiration by reducing the surface temperature and increasing the boundary layer resistance. Stomata Before harvest, most of the evaporation occurs from undersides of leaves via stomatal guard cells and adjacent cells (Kramer and Boyer, 1995). Stomata occur in many fruits at early stages of development, but sometimes they are not found in mature fruits of some species, for example, in the grape berry (Possingham et al., 1967). Orange has greatest stomatal density reported so far for any fleshy fruit (Banks, 1995). Stomata usually function less effectively in mature fruit (Blanke and Leyhe, 1988). In most cases it is reduced with maturation and usually of minor importance for fruit water loss during postharvest period (Ben-Yehoshua Rodov, 2003).

The lamb to the slaughter and The speckled band :: English Literature

Wide Reading: The lamb to the slaughter and The speckled band For me, a good murder mystery needs to contain a mixture of aspects. Like in mid-summer murders and Morse it needs to include the following things, a good setting, there needs to be a good setting so that it sets up the whole of the story, it needs to be somewhere quiet and peaceful. The characters need to be strong characters that all relate to each other, there also needs to be a twist in the characters to add depth an mystery, perhaps the last clue to the murderer. The murderer has to be someone unexpected, someone who perhaps wasn't the strongest character. The victim has to be someone who has mystery but perhaps gave the killer reason to, so you might feel that they deserved it but you might have sympathy for, it also needs to be someone you least expect to be killed, perhaps the stronger character. And the detective has to be someone who everyone can sort of relate to, who has a slight mystery behind him or her so that even when you think you know them there is a skeleton in their closet. The murder weapon has to be something of power and something that represents some element in the play. It also has to be something unexpected like an exotic animal or as in lamb to the slaughter, a leg of lamb! Also the plot has to be thick and unexpected, with plenty of twists and red herrings. It also needs to make the reader feel included in the story so you feel as if you were there. Finally the ending of the story has to be meaningful and it needs to draw a conclusion. The killer has to be found, the reasons to be explained and the murder it self be told and what happened prior to the event. This finishes off what happened and lets us draw our own conclusions, although for a good murder mystery something's need to be left a mystery. I am going to compare the different areas in each story. I shall be comparing the following  · Settings  · Characters The settings for Lamb To The Slaughter and The Speckled Band a very different. The setting for the speckled band is in Victorian England, in the earlier 1900's. it is set in a country town, in a big mansion. A wealthy family lives in it. It is torn apart by deceit, greed and the death of the lady of the household. The back ground to the story goes a little something like this. The lady of the Stoke morans first

Free Essays - Hamlet as a Tragic Hero :: Shakespeare Hamlet

An Examination of Hamlet as a Tragic Hero Webster’s dictionary defines tragedy as, â€Å"a serious drama typically describing a conflict between the protagonist and a superior force (such as destiny) and having a sorrowful or disastrous conclusion that excites pity or terror.†Ã‚   A tragic hero, therefore, is the character who experiences such a conflict and suffers catastrophically as a result of his choices and related actions.   The character of Hamlet, therefore, is a clear representation of Shakespeare’s tragic hero.   As the play’s tragic hero, Hamlet exhibits a combination of good and bad traits.   A complex character, he displays a variety of characteristics throughout the play’s development.   When he is first introduced in Act I- Scene 2, one sees Hamlet as a sensitive young prince who is mourning the death of his father, the King.   In addition, his mother’s immediate marriage to his uncle has left him in even greater despair.  Ã‚   Mixed in with this immense sense of grief, are obvious feelings of anger and frustration.   The combination of these emotions leaves one feeling sympathetic to Hamlet; he becomes a very â€Å"human† character.   One sees from the very beginning that he is a very complex and conflicted man, and that his tragedy has already begun. Hamlet’s anger and grief- primarily stemming from his mother’s marriage to Claudius- brings him to thoughts of suicide, which only subside as a result of it being a mortal and religious sin.   The fact that he wants to take his own life demonstrates a weakness in his character; a sense of cowarness, his decision not to kill himself because of religious beliefs shows that this weakness is balanced with some sense of morality.   Such an obvious paradox is only one example of the inner conflict and turmoil that will eventually lead to Hamlet’s downfall.   In addition to this internal struggle, Hamlet feels it is his duty to dethrone Claudius and become the King of Denmark.   This revenge, he believes, would settle the score for his mother’s incestuous relationship and would reinstate his family’s honor.   These thoughts are solidified in Act I, Scene 5, when his father’s ghost appears and informs Hamlet that is was Claudius who murdered him, and that Claudius deprived him â€Å"of life, of crown, and queen† (line 75).   This information leads to Hamlet’s promise to kill Claudius, while not punishing his mother for their incestuous marriage.   His statement, â€Å"thy commandment all alone shall live within the book and volume of my brain† (lines 102-103), demonstrates his adamant decision to let nothing stand in the way of his promise for revenge.

Origins of the Shadow in A Wizard of Earthsea Essay -- Essays Papers

Origins of the Shadow in A Wizard of Earthsea Ged, the main character in The Wizard of Earthsea, by Ursula K. LeGuin, through an act of pride and spite unwittingly unleashes a powerful shadow creature on the world, and the shadow hunts Ged wherever he goes. After failing to kill Ged the first time, he learns the only way to destroy the shadow is to find its name. What Ged must realize is the shadow was created by the evil in his own heart. Also, the shadow is not entirely evil, and Ged can actually draw strength from it. In doing so, Ged will realize that the only way to discover the shadow’s name is to discover that he and the shadow are one. Carl G. Jung in Man and His Symbols, describes the shadow as containing the hidden, repressed, and unfavorable â€Å"tendencies† of the conscious personality. â€Å"Such tendencies form an ever-present and potentially destructive ‘shadow’ to our conscious mind.† This shadow takes form in mythology as a dark, shadowy, and imposing figure or as â€Å"the cosmic powers of evil, personified by dragons and other monsters.† (Henderson 111) This shadow is shown to Ged in different forms: â€Å"...Like a clot of black shadow, quick and hideous...it was like a black beast, the size of a young child, though it seemed to swell and shrink; and it had no head or face, only the four taloned paws with which it gripped and tore.† (LeGuin 61) As it appeared when the shadow was first created. Later as the shadow pursued him, it held the same form. â€Å"The shadow did not have the shape of man or beast. It was shapeless, scarcely to be seen, but it whispered at him, though there were no words in its whispering, and it reached out towards him.† (LeGuin 81). Once Ged stops running, the shadow takes on a more identifiable form â€Å"...now some likeness to a man, though being shadow it cast no shadow.† The last form the shadow takes are the images people that Ged has come across in his life, â€Å"An old man it seemed, gray and grim, coming towards Ged; but even as Ged saw his father the smith in that figure, he saw that it was not an old man, but a young one. It was Jasper: Jasper’s insolent handsome young face, and silver-clasped gray cloak, and stiff stride. Hateful was the look he fixed on Ged across the dark intervening air...and it became Pechvarry. But Pechvarry’s face was all bloated and pallid like the face of a drowned man, and he rea... ... to face his fears. â€Å"In silence, man and shadow met face to face and stopped. Aloud and clearly, breaking that old silence, Ged spoke the shadow’s name and in the same moment the shadow spoke without lips or tongue, saying the same word: ‘Ged.’ And the two voices were one voice. Ged reached out his hands, dropping his staff, and took hold of the shadow, of the black self that reached out to him. Light and darkness met, and joined, and were one...’Estarriol’, he said, ‘look, it is done. It is over...the wound is healed...I am whole, I am free.’† (LeGuin 179-180) On the condition that one succeeds in assimilating and integrating the conscious mind the lost and regained contents. Since they are not neutral, their assimilation will modify the personality, just as they themselves will have to make certain changes. â€Å"If we could see our shadow, we should be immune to any moral and mental infection and insinuation.† (Jung 79) Bibliography: A Wizard of Earthsea, Ursula K. LeGuin, published by Bantam Spectra Books. Fantasy Novel Man and His Symbols, edited by Carl G Jung and M.-L. von Franz, Joseph L. Henderson, Jolande Jacobi, Aniela Jaffe, published by Dell Books, non fiction.

Child Abuse And Abandonment

Unfortunately, it is occurring more and more in today’s society that these defenseless children are being robbed of their childhood innocence and happiness and are being forced to face the cruel reality of our world at far too young an age. These Children are victims of neglect and abuse, primarily caused by family members or people they are close to. Child neglect is the most common form of abuse, and is therefore the main subject that will be covered in this essay.This disturbing and extremely common, yet rarely talked about topic effects at least one out of every 10 children under the age of 14 in Canada alone. Child abuse and neglect are one of the largest problems occurring in society, and in order for the situation to improve, we need to stop ignoring the fact that it is a daily reality, and become better educated on the topic and how to prevent it. After all, the children of today are the future of tomorrow, and they deserve to start their lives surrounded by love, and free from fear and pain.Many children these days take the love, support, and presence of their parents for granted, often starting arguments over unimportant things and getting upset when things do not go their way. Sadly, what they do not realize is that a large number of children do not get to know what a parent’s presence feels like, let alone having their constant love and support. Millions of children around the world suffer from abuse and neglect, and wake up every morning fearful of what the day will hold.There is no exact definition that holds enough value to be able to describe the fear and pain that these young children go through each day, but by law, child abuse has been defined as â€Å"an act, or failure to act, on the part of the parent or caretaker that results in the death, serious physical or emotional harm, sexual abuse, or exploitation of a child, or which places the child in an imminent risk of serious harm. † There are four kinds of child abuse; p hysical, sexual, emotional and neglect. All kinds of abuse are illegal in Canada and the United States.Although each type f child abuse is of great importance, neglect is the most common form of child mistreatment in Canada (accounting for 62% of all reported abuse cases), and can cause damage even more severe than that of any other form of abuse. Neglect is when the caregiver does not provide necessary attention to the child’s safety, physical, emotional or psychological needs. In severe cases, neglect can lead to abandonment, which is when a parent relinquishes permanent rights and claims to a child outside legal adoption.Child abandonment is a severe problem, accounting for almost half (43.3%) of all fatal child abuse cases. In Canada, there are over 15, 980 neglected children, and that number is only a rough estimate, because the majority of neglect cases are left unreported. The children that are more at risk of becoming victims are disabled children, who are twice as li kely, and aboriginal children, who make up the majority of child abuse and neglect victims in Canada. Many parents or caregivers who neglect and abandon their children do so because they suffer from depression, lack of initiative, futility, a low level of education, a poor socioeconomic status, unemployment, substance abuse or social isolation.Other factors that could lead to neglect and abandonment can include that the child was the outcome of sexual assault or incest, or is perceived by the caregiver as an obstacle to personal achievements. If a child suffers from neglect, signs of the abuse may include severe need of medical or dental care, frequent school absences, stealing food, begging for money, dressing inappropriately for the weather, not answering questions directly about his parents or caregivers, and drastic changes in personality and appearance. If a child is reported as being neglected or abused, Children’s Aid Society (CAS) goes to inspect the home.If the accus ations prove true, the child is then taken from the parent or caregiver (either temporarily or permanently, depending on the severity of the abuse), and is places either in the custody of another relative, or in foster care. The sentence of the caregiver depends on how severe the abuse or neglect is, and can vary from having to pay a fine, to losing custody of the child, to being imprisoned. As Canadian citizens and members of our community, it is our duty to protect the children by reporting any signs of abuse or neglect to the authorities.Unfortunately, not many people do so, and by consequence, the young children have no voice, and are forced to continue suffering in silence. One may not think that child abuse and neglect has much of an impact for the population, but in reality, it largely affects many aspects of today’s –and tomorrow’s- society. Economically, child abuse is very costly. Once a child had been taken out of the custody of his or her parents, th ey are often taken to hospitals where their medical needs are taken care of, and then placed into foster homes.The treatment  and trips to the hospital quickly become very costly, and the foster care alone costs the country over $6 billion a year. Also, each abandoned child could cost the government over $3,000 a day. Although the money is going towards the great cause of providing abused and abandoned children with a better life, it is a completely avoidable matter that is costing extreme amounts of money. Also, there has been a dramatic increase in child abuse and neglect since 1991, and the numbers are still growing. If this trend continues, there will be more children who are abused than those who are not.What this will mean for society is higher taxes, and adults who have more issues and lower skill levels. The effects of abuse and neglect on children are that they have poor social skills and lower education levels, a higher rate of mental and physical disabilities, delinquen cy, violence, drug abuse and depression. In addition, abused or neglected children have a higher tendency to abuse and neglect their own children later in life. This means that a large portion of our world will be governed by physically and emotionally damaged adults, who may do the same to their own children.This will result in many socioeconomic problems for our future. As was said before, the children today are the future of tomorrow, and if we want a good future for our world, we need to treat the children properly and give them the knowledge and love they deserve to become well-rounded adults. Countless organizations around the world work to improve the issue of child abuse, neglect and abandonment, as it is an increasingly important problem in our society. However, I have only selected one organization to write about- The Door of Hope.The Door of Hope is an organization located in Johannesburg, South Africa that has a mission to rescue and receive any abandoned, abused or orph aned babies and children in and around their city. They work to provide a temporary Christian home for all the children while seeking a forever family, suitable long term care or other permanent care for each one. The Door of Hope organization began in 1999, when the pastor of a small church in Johannesburg, named Cheryl Allen, learned that a high number of newly born infants were being abandoned.Cheryl realized that many of the young women abandoning their babies may have acted differently had there been an alternative. The church then made a â€Å"baby bin† in the side of the wall, where mothers could place their infants who would then be brought into the church and taken care of by the volunteers. When news spread, babies began being brought in by police, community members, hospitals and clinics. By having complete faith and reliance in God, the ministry has grown, and saves over 100 children’s lives each year.Because this organization is still relatively small, the y only have a few fundraisers, but are working hard to get more activities and more people to raise awareness and support their cause. Their annual fundraisers are; the Barnyard Fundraiser, a production that lets you experience the music and famous icons of the 80’s. It is a fun-filled all night event of music, comedy and dancing that includes dinner. They also sell Door of Hope memorabilia at the entrance.Another one of their fundraisers is the Momentum 94.7 Cycle Challenge, which is a bicycle race held in South Africa for any level of cyclist. They ask that participants do their best to raise as much money as possible for the cause, and that they purchase a door of hope shirt to wear on the day of the race. The Door of Hope is a strictly Christian organization that fully believes and trusts in God’s plan. Therefore, there are many possible parables and Beatitudes that could be connected to Door of Hope, but it is the fifth Beatitude that I think represents them the b est; â€Å"Blessed are the merciful, for they shall obtain mercy.†Mercy is having love towards those that are miserable and those that need some type of help or assistance. The merciful are those who are compassionate towards those who need mercy, and go out of their way to make the effort to help. Cheryl Allen and the volunteers at Door of Hope truly show that they are merciful by taking abandoned, abused and orphaned infants and children, many of whom are extremely ill or problematic. They spend their days tending to these young children to make sure they get the love and attention they need for no pay whatsoever, and are extremely humble about it.I believe that this is what makes them so merciful. They give all they have to help these infants, yet ask for nothing in return. The only reward they need is to see a child’s smile, knowing that their life has been saved, and that they will now be able to live to their fullest potential. If someone wanted to support the Do or of Hope Organization, they could either send a donation in the form of a cheque through the mail or by credit card over the internet. They could also â€Å"adopt a cot†, which is sending a monthly donation to provide a child with a bed and necessary supplies.A third option, which would be for the most dedicated of supporters, is to go volunteer at the organization. They accept international volunteers and will help pay for your travel and stay, but you must fundraise as well. The international volunteers have to be 18-60 years of age, will stay from 1-12 months and will help with the babies daily, along with other responsibilities. I think that the Door of Hope is a truly spectacular organization, and I hope that when I graduate from Highschool, I will be able to help as an international volunteer.In conclusion, child abuse and neglect is an extreme problem plaguing our society, and we need to help bring a stop to it. If not, the effects of this abuse will impact many aspe cts of our future, as well as damaging the lives of countless children and denying them of their full potential. Become an active member of your community, and when you suspect a child is being abused, do not hesitate to report it. You could be saving their life.

Characters in Hamlet Essay

In Hamlet, Polonius interacts in very different ways with the various characters. While talking with Reynaldo, he speaks in a sneaky, sly and clever manner. When talking with his daughter Ophelia, he seems very concerned. When talking with Hamlet, he seems confused, not knowing what Hamlet is talking about. When talking with the Players, however, he acts imperiously, exerting his authority over them. When talking with Reynaldo, Polonius speaks in a clever and sneaky manner. He tells Reynaldo exactly how to speak to people while trying to find Laertes. He tells him exactly what to say so that the other person will be forced to tell him of the whereabouts of Laertes. He told him that he should say â€Å"you may say, not well. But, if ‘t be he I mean, he’s very wild.† Polonius’s sneakiness is seen through his clever tactic in sending Reynaldo to Paris for the purpose of discovering Laerte’s habits. When talking with his daughter Ophelia, however, he seems genuinely concerned. This is true because in regard to Laertes, Polonius was looking for an excuse to punish or disown him for leaving the country. However, by Ophelia, Polonius is really concerned. While speaking with Gertrude and Claudius, Polonius is very honest. He comes before the king and queen bringing good news. The good news is that he knows why Hamlet is so upset. The reason is because of Ophelia. After discovering Hamlet’s lust for his daughter, he told Ophelia to stop meeting Hamlet and to send back Hamlet’s love letters. Then, he asks the king and queen if there has ever been a time where he had not told the truth. Claudius responds â€Å"not that I know.† To prove his fidelity, he is prepared to have his head chopped off if he is wrong. When talking with Hamlet, Polonius is confused. Polonius does not understand what Hamlet is talking about. When confronting Hamlet, Hamlet is reading a book. When asked what kind of book he is reading, Hamlet responds â€Å"Slanders sir.† While speaking with the Players, Polonius is arrogantly domineering. The Players come to perform a play for hamlet in order to cheer him up. While  doing their play, Polonius rudely interrupts them. He makes comments such as â€Å"This is too long.† In addition, after the play, when Hamlet instructs Polonius to treat the Players well, Polonius responds arrogantly, â€Å"My lord, I will use them according to their desert.† In response to Polonius’s disrespectful statement, Hamlet says â€Å"God’s bodykin’s man, much better. Use every man after his desert, and who should ‘scape whipping? Use them after you honor and dignity.† In conclusion, Polonius’s character varies with every individual he interacts with. It varies to the extent that his character can change from extremely honest to sly and sneaky. Also, it can change from confused to arrogantly domineering. His unique character traits differ greatly to the extent that by the end of Act II, Polonius is viewed as a necessary and crucial character in the play.