Membrane: Structure And Function

Membrane: Structure And Function Chapter title: Membrane Structure and Function. The ability of the cell to discriminate in its chemical exchanges with the environment is fundamental to life, and it is the plasma membrane that makes this selectivity possible. Membrane The membranes that are found within cells (plus the plasma membrane surrounding cells) consist of phospholipids (and other lipids plus membrane proteins) arrayed by hydrophobic exclusion into two-dimensional fluids known as known as lipid bilayers Phospholipids Phospholipids are amphipathic molecules meaning that they have both a hydrophobic and a hydrophilic end Lipid bilayer Phospholipids can exist as bilayers in aqueous solutions The hydrophobic portion of the phospholipid is shielded in middle of these bilayers The hydrophilic portion is exposed on both sides to water Lipid bilayers are held together mainly by hydrophobic interactions (including hydrophobic exclusion) Fluid mosaic model The plasma membrane contains proteins, sugars, and other lipids in addition to the phospholipids The model that describes the arrangement of these substances in and about lipid bilayers is called the fluid mosaic model Basically, membrane proteins are suspended within a two-dimensional fluid that in turn is made up mostly of phospholipids Cholesterol Cholesterol, a kind of steroid, is an amphipathic lipid that is found in lipid bilayers that serves as a temperature-stability buffer At higher temperatures cholesterol serves to impede phospholipid fluidity At lower temperatures cholesterol interferes with solidification of membranes (e.g., cholesterol functions similarly, in the latter case, to the effect of unsaturated fatty acids on lipid-bilayer fluidity) Cholesterol is found particularly in animal cell membranes Membrane proteins Proteins are typically associated with cell membranes Integral membrane proteins are typically hydrophobic where they interact with the hydrophobic portion of the membrane or hydrophilic where they interact with the hydrophilic portion of the membrane and overlying Functions of membrane proteins Functions of membrane proteins include: Transport of substances across membranes Enzymatic activity cell communication Cell-to-cell joining Attachment to the cytoskeleton and extracellular matrix Selective permeability Lipid bilayers display selective permeability In general, intact lipid bilayers are permeable to: Hydrophobic molecules (including many gasses) Small, not-ionized molecules   Simultaneously, lipid bilyaers are NOT permeable to: Larger, polar molecules (e.g., sugars) Ions, regardless of size Thus, lipid bilayers are selectively permeable barriers that allow the entry of small or hydrophobic molecules while blocking the entry of larger polar or even small charged substances Transport across membranes Movement across membranes is important, for instance as a means of removing wastes from a cell or bringing food into a cell Categories of substance transport across membranes include: Passive transport Facilitated diffusion Active transport (including cotransport) Endocytosis, phagocytosis, and exocytosis, also considered below, technically are not mechanisms of movement of substances across lipid bilayers (though these do represent movements of substances into and out of cells; to be movement across the euakaryotic cell membrane, a substance must actually pass through an endomembrane lipid bilayer) Note that in considering transport across membranes we will once again confront the concept of movement away from or towards equilibrium, i.e., endergonic and exergonic processes There are three basic types of movement across membranes: simple diffusion, passive transport, and active transport: Simple diffusion Simple diffusion is the movement of substances across lipid bilayers without the aid of membrane proteins This image (below) shows how substances move through membranes, regardless of net direction and concentration gradients: This image (below) shows how substances net move through membranes in the direction of their concentrations gradients (i.e., with their concentration gradients)-note that regardless of how net movement is accomplished, all simple diffusion across membranes occurs in the manner illustrated above, i.e., it is a process that is driven by the random movement of molecules: This figure (below) indicates the kinds of molecules that are capable of moving across membranes via simple diffusion: Passive transport Passive transport is the term used to describe the diffusion (as well as what is termed facilitated diffusion, below) of substances across lipid bilayers Passive transport is a consequence of movement through the lipid bilayer (whether by diffusion through the membrane or with movement across facilitated by an integral membrane protein) a concentration gradient thereby contrasting with active transport Down the concentration gradient Diffusion is a random process that tends to result in the net movement of substances from areas of high concentration to areas of low concentration This includes movement from one side of a permeable lipid bilayer to the other from the higher concentration side to the lower concentration side (i.e., passive transport) Movement from high to low concentration areas is described as going down its concentration gradient. The direction of movement of substances across lipid bilayers by passive transport is controlled by concentration gradients Osmosis Movement of water across selectively permeable membranes down the water concentration gradient is called osmosis Note that this is movement toward equilibrium (exergonic process) Tonicity (isotonic, hypertonic, hypotonic) Picture a membrane separating two solutions, one side with a higher solute concentration than the other The side with the higher solute concentration is said to be hypertonic The side with the lower solute concentration is said to be hypotonic (I keep track of the difference by recalling that a hypodermic syringe is so named because the tip of the needle is placed beneath the dermis, i.e., under the skin; a hypotonic solution has a solute concentration that is beneath, i.e., lower than that of the reference solution) If both sides have the same solute concentration, they are said to be isotonic Animal cells and tonicity Normally animal cells are bathed in an isotonic solution Placement of an animal cell in a hypertonic solution causes the cell to shrink (i.e., water is lost from the cell by osmosis) Placement of an animal cell in a hypotonic solution causes it to take on water then burst (lyse, i.e., die) (water is gained by the cell, lost from the environment bathing the cell, both by osmosis) Turgidity Normally a plant cell exists in a hypotonic environment The hypotonicity causes the plant cytoplasm to expand However the plant cell does not lyse and this is due to the presence of its cell wall This conditions is known as turgidity (i.e., the pressing of the plant plasma membrane up against its cell wall) Plant cells prefer to display turgidity Plasmolysis A plant or bacterial cell placed in a hypertonic environment will show a shrinkage of its cytoplasm This shrinkage is called plasmolysis At the very least plasmolysis will inhibit growth Often plasmolysis will lead to cell death This is the principle upon which foods are preserved in highly osmotic solutions (e.g., salt or sugar); such solutions impede most microbial growth Flaccidity Plant cells bathed in isotonic solutions will fail to display turgidity Instead they display flaccidity At a whole-organismal level, flaccidity is otherwise known as wilting Transport proteins Substances (e.g., sugars) that are not permeable through lipid bilayers may still cross via membrane-spanning transport proteins Facilitated diffusion Facilitated diffusion is the movement of a substance across a membrane via the employment of a transport protein, where net movement can only occur with the concentration gradient, is called facilitated diffusion The key thing to keep in mind is that facilitated diffusion, in contrast to other mechanisms of transport-protein-mediated membrane crossing, does not require any input of energy beyond that necessary to place the protein in the membrane in the first place (i.e., facilitated diffusion is an exergonic process) Passive versus active transport Two general categories of transport across membranes exist: Those that dont require an input of energy (passive transport, simple diffusion, facilitated diffusion) Those that do require an input of energy (active transport) Passive Transport Active Transport Concentration gradient With (Down) Against (Up) Without Integral Protein Yes (Simple Diffusion) No With Integral Protein Yes   Yes Examples Small or Hydrophobic Substances, Osmosis(by simple diffusion) or Not-Small or Charged Substances (by facilitated diffusion) Cotransport, Proton Pump, Sodium-Potassium Pump Active transport Active transport is the movement of substances across membranes against their concentration gradients Moving things against their concentration gradients requires an expenditure of energy (i.e., it is an endergonic process) This energy can be in the form of ATP (e.g., sodium-potassium pump) This energy can also be in the form of electrochemical gradients (i.e., cotransport) Note that the movement of substances by active transport is in a direction that is away from equilibrium Sodium-potassium pump One means by which cells actively transport substances across membranes is via the sodium-potassium pump The sodium-potassium pump is important especially in animal cells, and is the means by which the sodium-potassium electrochemical gradient is established by these cells Proton pump The sodium-potassium pump is the means by which animal cells generate membrane potentials In bacteria, plants, and fungi, proton pumps play the same role The proton pump is simply ATP-driven active transport in which the substance pumped across the membrane is a hydrogen ion Cotransport Much of the active transport accomplished by a cell isnt directly powered by ATP Instead, much active transport is powered by membrane potentials (i.e., electrochemical gradients) Such electrochemical-gradient-driven active transport is called cotransport In cotransport, one substance, such as a sugar, is driven up its concentration gradient while a second substance, e.g., sodium ions or protons, are allowed to fall down their electrochemical gradient; the energy gained from the latter is employed to power the former (i.e., energy coupling) Endocytosis Endocytosis is a general category of mechanisms that move substances from outside of the cell to inside of the cell, but neither across a membrane (technically) nor into the cytoplasm (again, technically speaking) Instead, substances are moved from outside of the cell and into the lumens of endomembrane system members To enter the cytoplasm an endocytosed substance must still be moved across the membrane of the endomembrane system, e.g., following their digestion (typically hydrolysis) to smaller molecules Examples include: phagocytosis, pinocytosis, and receptor-mediated endocytosis Phagocytosis Phagocytosis is the engulfing of extracellular particles is achieved by wrapping pseudopodia around the particles, thus internalizing the particles into vacuoles Amoebas employ phagocytosis to eat Most protozoa obtain their food by engulfing, i.e., via some form of endocytosis The advantage of endocytosis as a mechanism of food gathering has to do with minimizing the volume within which digestive enzymes must work in order to digest food, i.e., the engulfed food particle Cells in our own bodies, called phagocytes and macrophages employ phagocytosis to engulf (and then destroy) debris floating around our bodies as well as to engulf and destroy invading bacteria Pinocytosis Pinocytosis is the engulfing of liquid surrounding a cell This is how developing ova obtain nutrients from their surrounding nurse cells (ova are very large cells so have surface-to-volume problems-pinocytosis solves the problem of nutrient acquisition by allowing nutrients to be obtained across many internal membranes rather than being limited to crossing the plasma membrane) Receptor-mediated endocytosis Receptor-mediated endocytosis involves the binding of extracellular substances to membrane-associated receptors, which in turn induces the formation of a vesicles Exocytosis Exocytosis is more or less the mechanistic opposite of endocytosis

Bronfenbrenner Ecological Systems Theory

Bronfenbrenner Ecological Systems Theory The microsystem is the most influential system because the child has direct interaction with these individuals; that interaction occurs on a consistent basis over an extended period of time (Brofenbrenner, 2004). Family is the most significant relationship of the microsystem; they play an intricate part in the ecological human development. The most time is spent at home with the family; they provide shelter and safety, and also provide emotional support for the child. The parent for example, interacts with the child on a daily basis, they provide a safe and healthy relationship and an environment for them to grow and prosper. The way the parent plays with the child, teaches them, and communicates with them has a lot of influence on their development. The parenting style a child receives paves the way in their ability to communicate with others, their self-esteem, and the attitude and behaviors they exude. The main parenting styles are authoritarian, authoritative, permissive, and non-involved. The authoritarian parent is strict and demanding; this creates a child that grows up to behave withdrawn, fearful, and distrustful of others. On the opposite end of the spectrum is the permissive parent. The child raised in a permissive household is more likely to be aggressive, impulsive, and have little self-reliance. The healthy balance between the two styles is the authoritative parent who raises a content, cooperative, and self-reliant child (Berns, 2010). The parent gives the child the ability to create secure attachments with others and to have a healthy and positive disposition. The emotional connectivity of this relationship is a direct reflection of a childs ability to connect and communicate with all other systems. Parenting styles are not the only ways that family can influence development; family structure also has a great impact. The nuclear family consists of a mom, a dad, and the children, but not all households are structured this way. Divorce is an unfortunate reality in this day and age and the adaptation plays a large role for the child. Not only does the child not get to live in a household that has both parents which provides a healthy surrounding and assures the child of love, but they may have to listen to the consequences of how each parent deals with the divorce itself. Counseling, mediation, custody battles, and fighting are all situations that the child may be surrounded by. The financial consequences will affect the family and the child would not live in the same lifestyle as they would if both parents were together because the income would be cut in half. Peers, community, and schools also affect the child. The peer groups help the child gain independence and discover their sense of self. Negative experiences with peers such as bullying can hurt the childs self-esteem, affect how they interact with their others, and their ability to communicate and socialize with their peers with ease. School is another very important relationship. This gives the child a chance to learn the fundamentals needed as an adult and to help them develop different skills and appropriate behavior. Every child learns differently; they may be an auditory, visual, spatial, or kinesthetic learner. It is the teacher and schools responsibility to discover this and take the best course of action to implement and teaching style that works best for the child. The second system that influences development is the mesosystem. Mesosystems may be described a links in a chain. They consist of linkages and interrelationships that exist between two or more of the individuals microsystems. These interrelationships involve a variety of settings that the child is immersed in; the influences that bind us together (Feldman, 2008). Examples of this system may be the linkage between family and peers, family and school, school and community, and so on. Schooling is the perfect example of the mesosystems linkage between family and school. The more involved the parent is with the childs school, increases the likelihood of that child excelling in school, receiving higher grades, and attending college in the future. The involvement that the family has with the childs learning before they enter school creates a positive attitude towards their future learning. When it comes to the childs relationship with school, the more perceptive that the family and teachers are in their learning with affect their educational experience. They will learn how to complete tasks, problem solve, and understand rewards and consequences. There is also an important linkage between school and the community. Higher funded schools have more resources available to students; these resources extend the learning process. More books, informative television programs and movies, supplies, crafts, and the ability to go on field trips may provide a more stimulating environment and positive outlook on a childs involvement and learning at school. Community support and donations can help increase learning in the classroom. The exosystem is the third system of Bronfenbrenners theory of human development. These influences are indirect; the child itself is not an active participant, however it does have an impact on an active member of  their microsystem. This may consist of the parents career or financial situation, political systems, social support networks, etcetera. As stated above, exosystems have an indirect affect on the child through career, their socioeconomic status, or the government. A parents socioeconomic status affects the child because they may not have the means to purchase educational materials or live in a nice home, if they have a home at all. Children born into poverty statistically have lower self-esteem, are less likely to excel in school or are more likely to drop out, and they are more susceptible to violence and crime. A parents job may also influence a child indirectly. A parent that has to travel a lot for work or stay late hours must place their child in non-parental child care. Different forms of this non-parental care will affect that child differently. There are child care centers, family day cares, and in-home care of a nanny that may be used to watch over the children. The accreditations are different for each type, and there are different programs, such as health, nutrition, and learning programs. Although there are many different options that the family has when they do not have the ability to stay at home with the child, but it is still no substitute for being cared for by their parent. Although sometimes a parent has no choice but to place their child in a day care program, there can be some developmental consequences to this. The child will be able to socialize with peers more easily, but they tend to be less cooperative and unresponsive with adults. The longer the child stays in non-parental care, the more likely they are to develop insecure attachments, are at risk for problems with emotions and in behavior. They are also more likely to be aggressive and defiant. The final system involved is the macrosystem. This system is societal and has a larger context involved in culture. This type of system influences the developing child in a much broader context; the beliefs of the family and their lifestyle, education, religion, and mass media. What society places as the social norms, expected roles, and what a relationship is supposed to look like. Macrosystem influences come from cultural views in society. Views of roles, such as gender roles, have a set of associated behaviors that are expected in that individual. A boy must be a strong provider and shouldnt cry, or a girl should be a nurturer and domesticated are examples of these gender roles inflicted on society. Different values and lifestyle are also a large influence to that child. Believing in the necessity of owning a large home, having expensive cars, or that as adults, they need to be married with a white picket fence and 2.5 children. Morals and values stem from the familys beliefs and religious law; although sometimes the religious laws coincide with federal. Religions such as Catholicism, Lutheranism, Buddhism, Hinduism, and Atheism, are all extremely different from one another and go along a different belief system with different sets of values which influence the individual. Children that grow up believing in some form of Christianity may have different values than a child that grew up in an Atheist household. Mass media and culture are intertwined, but the influence of media is widespread and comes in a variety of forms; screen media, print media, audio media, and interactive media. Media influences value, beliefs, attitudes, and behavior explains Berns (2010, pg 321). At least one form of media can be found basically anywhere and is used to communicate and spread information to a large group of people simultaneously. Screen media that comes in television form spreads so quickly and easily influences young and impressionable minds. In some respects the exposure can be a good thing; it is mentally stimulating, can be educational and useful in a classroom to help students understand information in a different way. Programs for younger children such as Dora the Explorer and Blues Clues are a great way to teach young children colors, numbers, mathematics, and linguistics. Unfortunately there are downsides to this. Not all programs are suitable for young children; they may contain graphic viol ence, foul language, and sexually explicit material that is inappropriate for this age group. This information can ingrain the idea of what life should be like or how the child should behave, this sets up negative associations and roles. Violent and graphic material could result in negative behaviors such as aggression or bullying others, it may also cause the childs imagination to run wild which may be scary, exciting, or intimidating for the child. Too much time in front of the television, or focused on any type of media really, can take away from time spent with the family and engaging in family activities, or it can also affect physical activity. Print media is found in books, newspapers, magazines, and articles. Print media is beneficial because it enhances language and reading skills, it helps with comprehension, and overall cognitive development. Children may understand the sense of who they are because of all the stories and tales they read. A downside to this is that the ch ild may confuse negative actions and material with reality and fantasy. Just as with screen media, print, audio, and interactive media instill the ideas behind different stereotypes; this can be a major concern for problems in the future and self-esteem. Overall between all forms of media there are positives and negatives. They increase cognitive functioning and development, but children are impressionable and graphically violent and sexually explicit material is not good for young children and should be monitored by the parent. It is now apparent that ecological systems affect development Urie Bronfenbrenner was correct in his theory of the bioecological model of human development. There is significant data to show how influential the four systems influence a child. The microsystem consists of close intimate relationships of those in direct contact with the child; they are involved on a consistent basis and appear to be the most influential relationship. Family, peers, school, and the community are all examples of a microsystem. They all have a large impact on the childs socialization skills. Because a child spends so much time with their parents, this is the foundation for success. Teaching their children early what behaviors are acceptable or not, having a comforting and balanced parenting style will really help the child be cooperative, self-reliant, and content. Placing a strong focus on the importance of academics will help the child to succeed in school, also choosing the correct school to help the st udent learning in an environment suitable for their needs. Peers have a massive impact on the childs communication and interaction with others so its important that the parent keep positive influences around that child. The microsystem is the primary system of influence so keeping secure, positive, healthy relationships will help the childs development as they begin to feel the effects of the other systems. Like the links in a chain, the mesosystem combines the importance of the  impact that the microsystems have on each other. Just as school and family influence a child, the relationships between the two systems also have a direct impact on the child. This does not only consist of the two relationships, but all relationships in the microsystem. The indirect affect of the exosystem, such as the stressors of a parents career, will have its own impact. Long hours at the job can result in the child being enrolled in some sort of non-parental child care. The type of care provided coul d benefit the child in their education and learning skills, but may also have a negative impact on their emotional comfort and attachment caused by the lack of the parent being around. Finally, the macrosystem is the combination of culture, religion, mass media, and other influences that are widespread. Mass media has many benefits to the childs development. Media is mentally stimulating, it can increase imagination, and teach the child different skills such as language, communication, mathematics, colors, and other skills. Parents do need to monitor the media that a child does interact with. The graphic violence and sexually explicit material can be damaging for young and influential minds. They can create different stereotypes that can affect the way the child socializing with others, or their sense of self. The more time spent around different forms of media can take away from the quality time spent with the family, and can decrease the amount of physical activity for the child. Overall, the four different systems involved in Bronfenbrenners bioecological model of human development massively impact the socialization and cognitive development of a child.

Comparison of Miracle on St. Davids Day by Gillian Clarke and Daffodil

Comparison of Miracle on St. David's Day by Gillian Clarke and Daffodils by William Wordsworth 'Daffodils' was written by William Wordsworth approximately a century before 'Miracle on St. David's Day' was written by Gillian Clarke. Due to this, the poems differ greatly in their style and language. Observing the poems at first glance, it is obvious that they also contrast in content, however at greater depth, the connections between them are made obvious. In this essay, I will be discussing the connections and differences between the two poems. The daffodil is the national symbol of Wales; it represents hope, joy and celebration. Both of the poets make this markedly palpable using this as a theme for their poems. In 'Miracle on St. David's Day' daffodils are mentioned at the beginning and end of the poem, carrying significance as it is they that remind the 'big, dumb labouring manà ¢? ¦' of a time when he had something to say. The man speaks for the first time in forty years, reciting the poem 'Daffodils' implying that this is what he has to say: the joy and hope evoked in him by both the daffodils that he sees and the poem 'Daffodils'. Wordsworth is less subtle is his regard of daffodils, his poem is more conspicuous in portraying the 'fluttering dancing jocund ' daffodils as they fill his heart with pleasure and this image of the daffodils is the same throughout the poem. Both poems depict how it is the daffodils that evoke some form of emotion in either the author himself, or a character in the poem. In 'Miracle on St. David's Day' the 'yellow and open-mouthed [daffodils]' and the 'rhythms of the poems' remind him that 'once he had something to say' and brings him out of his 'dumbness of misery', w... ... importance of a word or emotion ' I gazed- and gazed ' To gaze implies to watch with a certain amount of emotion, unlike to simply look at something. By repeating the word gaze, he emphasises that the flowers actually meant something to him. Wordsworth also uses onomatopoeia to allow the reader to visualise the description, ' fluttering ' The word allows the reader to see the daffodils fluttering, like a butterfly. These descriptive words are often used in association with a well-known description for example: the fluttering butterflies. Having studied both poems in depth, it is clear that they have more differences than similarities. However, they both have the same underlying theme of something wonderful happening that should be treasured, although they have presented this theme differently to the reader (different setting, characters, topic etc.). Comparison of Miracle on St. David's Day by Gillian Clarke and Daffodil Comparison of Miracle on St. David's Day by Gillian Clarke and Daffodils by William Wordsworth 'Daffodils' was written by William Wordsworth approximately a century before 'Miracle on St. David's Day' was written by Gillian Clarke. Due to this, the poems differ greatly in their style and language. Observing the poems at first glance, it is obvious that they also contrast in content, however at greater depth, the connections between them are made obvious. In this essay, I will be discussing the connections and differences between the two poems. The daffodil is the national symbol of Wales; it represents hope, joy and celebration. Both of the poets make this markedly palpable using this as a theme for their poems. In 'Miracle on St. David's Day' daffodils are mentioned at the beginning and end of the poem, carrying significance as it is they that remind the 'big, dumb labouring manà ¢? ¦' of a time when he had something to say. The man speaks for the first time in forty years, reciting the poem 'Daffodils' implying that this is what he has to say: the joy and hope evoked in him by both the daffodils that he sees and the poem 'Daffodils'. Wordsworth is less subtle is his regard of daffodils, his poem is more conspicuous in portraying the 'fluttering dancing jocund ' daffodils as they fill his heart with pleasure and this image of the daffodils is the same throughout the poem. Both poems depict how it is the daffodils that evoke some form of emotion in either the author himself, or a character in the poem. In 'Miracle on St. David's Day' the 'yellow and open-mouthed [daffodils]' and the 'rhythms of the poems' remind him that 'once he had something to say' and brings him out of his 'dumbness of misery', w... ... importance of a word or emotion ' I gazed- and gazed ' To gaze implies to watch with a certain amount of emotion, unlike to simply look at something. By repeating the word gaze, he emphasises that the flowers actually meant something to him. Wordsworth also uses onomatopoeia to allow the reader to visualise the description, ' fluttering ' The word allows the reader to see the daffodils fluttering, like a butterfly. These descriptive words are often used in association with a well-known description for example: the fluttering butterflies. Having studied both poems in depth, it is clear that they have more differences than similarities. However, they both have the same underlying theme of something wonderful happening that should be treasured, although they have presented this theme differently to the reader (different setting, characters, topic etc.).

Comparing three b2b or b2c web strategies :: essays research papers

I. Introduction The worldwide network of computers, called "Internet", provides opportunities for a company to do business in cyberspace. Organisations find it more and more important to represent them on the Internet to get more customers, to increase the public's awareness of the companies and their products, and to sell more of their products. However, corporate leaders are finding it difficult to keep up with fast-moving markets and the customer conditions that are the hallmark of the Internet. There are numerous and widely varying predictions of the potential of doing business via the Internet, including the increasing numbers of people with Internet access, of corporate Web sites, of Web spending by advertisers, and of total online shopping. Yet, confusion abounds concerning exactly what is happening, how much potential there really is, and what businesses should be doing to take advantage of it. The very nature of commerce on the Net can be baffling, even to the experienced marketer . Both businesses and consumers perceive many obstacles to successful online commerce. In order to successfully cultivate online market share, companies are compelled to design marketing strategies specifically for the information highway. I.A. Popularity of the Internet From its comparatively humble beginnings in the 1960s as a means for protecting US mainframe computer systems in the Cold War, to a 1970s link for scientists and academics to share data and research, the Internet has blossomed in the 1990s into the information age's curious marriage of the personal computer and citizens' band radio (Hof and Verity, 1994), instantaneously linking a user with the whole electronic world and providing the means to interact with that world. This explosive growth of the Internet, including commercial networks and services, has been accompanied by an astounding increase in the population of Internet users. The huge potential of customers and consumers has businesses scrambling to get on to the Web, with its low cost and broad reach. Millions of people worldwide can utilize the Web's affordable and easy access to view product, service and information offerings from an unknown number of potential entrepreneurs. (Chaffey et. al., 2003) Estimates say that the business side of the Internet is small today, but with untold billions in potential sales looming ahead. The prospect of millions of bright, well-educated, upwardly mobile people searching for some new outlet in which to spend their money has been too attractive for many businesses to ignore, in spite of slow initial momentum (Johnson, 1995).

Commanding Lady Fortune: Machiavelli’s Theory of History Essay

Commanding Lady Fortune: Machiavelli’s Theory of History Machiavelli opens his Discourses on Livy by declaring that what will follow will be entirely revolutionary—â€Å"a path yet untrodden by anyone†Ã¢â‚¬â€but then quickly backs down from such assertions, shifting his focus away from his own efforts to the modern views of the ancients, and leaving the nature of this revolutionary undertaking ambiguous (Discourses, 5) . Indeed, the purpose of the whole work is repeatedly skirted in the preface. Machiavelli instead focuses on the distinction between the moderns and the ancients, mourning the superficial modern adoption of ancient ideas in art and law that lacks a deeper understanding of the philosophical underpinnings of ancient thought. He leaves us with only a vague description of his purpose in writing the Discourses—â€Å"so that those who read these statements of mine can more easily draw from them that utility for which one should seek knowledge of histories† (Discourses, 6). What the specific utility of history is, however, and what is so novel about his treatment of it, Machiavelli does not say. However, within the preface, and throughout his subsequent treatment of the idea of history in both the Discourses and The Prince, it becomes clear that he is indeed arguing something revolutionary through his use of history as a guide for politics. He chastises the moderns for â€Å"judging that imitation is not only difficult but impossible—as if heaven, sun, elements, men had varied in motion, order, and power from what they were in antiquity,† that is, for being deceived by Christianity into believing that its inception had fundamentally altered the nature of the world, and that a distinction between the ancients and the moderns is anything... ...lf than of the prince he has been hired to serve, meaning that, because Machiavelli also believes in a human nature that is at its foundation, deeply self-serving, a monarch can have no true advisors and is doomed to failure (Prince, 93). In a republic, however, men like Machiavelli are free to look out for their own good while charting a course for the state, as both goods are aligned (Discourses, 130). While the prince of a republic may himself only possess the second kind of mind and be unable by his nature to come to such a broad understanding of history and the causality of human events that Machiavelli has, it is enough that he has among his advisors such men as Machiavelli. Thus, ultimately, Machiavelli’s â€Å"yet untrodden path† turns out to be the creation of a method for government that is premised on the ability to master every kind of manifestation of fortune. Commanding Lady Fortune: Machiavelli’s Theory of History Essay Commanding Lady Fortune: Machiavelli’s Theory of History Machiavelli opens his Discourses on Livy by declaring that what will follow will be entirely revolutionary—â€Å"a path yet untrodden by anyone†Ã¢â‚¬â€but then quickly backs down from such assertions, shifting his focus away from his own efforts to the modern views of the ancients, and leaving the nature of this revolutionary undertaking ambiguous (Discourses, 5) . Indeed, the purpose of the whole work is repeatedly skirted in the preface. Machiavelli instead focuses on the distinction between the moderns and the ancients, mourning the superficial modern adoption of ancient ideas in art and law that lacks a deeper understanding of the philosophical underpinnings of ancient thought. He leaves us with only a vague description of his purpose in writing the Discourses—â€Å"so that those who read these statements of mine can more easily draw from them that utility for which one should seek knowledge of histories† (Discourses, 6). What the specific utility of history is, however, and what is so novel about his treatment of it, Machiavelli does not say. However, within the preface, and throughout his subsequent treatment of the idea of history in both the Discourses and The Prince, it becomes clear that he is indeed arguing something revolutionary through his use of history as a guide for politics. He chastises the moderns for â€Å"judging that imitation is not only difficult but impossible—as if heaven, sun, elements, men had varied in motion, order, and power from what they were in antiquity,† that is, for being deceived by Christianity into believing that its inception had fundamentally altered the nature of the world, and that a distinction between the ancients and the moderns is anything... ...lf than of the prince he has been hired to serve, meaning that, because Machiavelli also believes in a human nature that is at its foundation, deeply self-serving, a monarch can have no true advisors and is doomed to failure (Prince, 93). In a republic, however, men like Machiavelli are free to look out for their own good while charting a course for the state, as both goods are aligned (Discourses, 130). While the prince of a republic may himself only possess the second kind of mind and be unable by his nature to come to such a broad understanding of history and the causality of human events that Machiavelli has, it is enough that he has among his advisors such men as Machiavelli. Thus, ultimately, Machiavelli’s â€Å"yet untrodden path† turns out to be the creation of a method for government that is premised on the ability to master every kind of manifestation of fortune.

Female Political Candidacy :: Politics Political Science

Female Political Candidacy Abstract Factors which influence female political candidacy were investigated. The results indicated significant gender differences on the following hypotheses: H1: Female and male political leaders will differ in their uses of interpersonal power; H2: Female and male political leaders will identify different motivations in seeking public office; and, H3: Female and male political leaders will differ in their perception of barriers to participation as political candidates. The secondary perspective of race was also considered but was not found to be a significant barrier to female candidacy. This significantly predictive model has regional and international implications, and future studies will tested it comparatively by state and region to affirm its generalizability. Female Political Candidacy: A Racial and Gender Perspective This study examines the use of interpersonal power by females in elected political positions, the factors that influence women to run for elected office, and the barriers that hinder female candidacy. Drawing from three areas of gender difference - women and development (IWPR, 2000), institutionalization of power relationships (Parsons, 1969), and socialization of gender roles (Bennett and Bennett, 1999; Lindsey, 1997) - the research focuses on women in elected political leadership positions using a comparison of women and men matched by elected positions in the State of Mississippi, USA. The hypotheses were: H1: Female and male political leaders will differ in their uses of interpersonal power; H2: Female and male political leaders will identify different motivations in seeking public office; and, H3: Female and male political leaders will differ in their perception of barriers to participation as political candidates. The secondary perspective of race is evaluated using statis tical methods on a non-matched comparison of African Americans and Caucasians who responded to the gender study. Economic arguments and incentives for policy supporting broad-based political representation are numerous. There is widespread acceptance that peoples who have little political voice are overlooked in the distribution of public goods and have less access to education and health. Kenworthy and Malami (1999) note that representative critical mass necessary for females as a social group to exert a substantial influence on politics is considered to be 30% of a legislative body, while Harvard sociologist Rosabeth Moss Kantor puts representation at closer to 50% to make a difference in the culture of an institution (Ivins, 2001). The United States Agency for International Development notes that while almost all peoples around the world, specifically women, have a legal right to vote, actual female participation is inhibited by cultural, social, economic, legal and educational constraints (USAID Fact Sheet, 1997).

Ophelia in William Shakespeares Hamlet Essay -- William shakespeare h

Ophelia in William Shakespeare's Hamlet â€Å"Follow her close, give her good watch, I pray you† (IV.5.73). Ostensibly, Shakespeare’s Hamlet is the riddling, enigmatic, inscrutable theatrical character par excellence. His motives, madness, conflicting morals and existential struggles are ambiguous to say the least. When analysing his character, Laertes and Fortinbras are often brought in as examples of less extreme characters dealing with similar but more tangible dilemmas. The idea that there may be someone who exceeds Hamlet in instability and incomprehensibility is unfathomable. But if one looks at the character of Ophelia, this notion not only becomes a viable possibility: it becomes unignorable. For while Hamlet is constantly struggling to define himself, leaving a trail of cast-off identities, disgustedly flinging one black outfit after another out of his wardrobe as he tries to remain true to himself, his father’s memory, and his stirring unconscious, we only see Ophelia in borrowed robes. She is dressed up like a dummy, paraded around, and dismissed. With her f inal exit, we are left with a handful of ill-fitting stage costumes, none of them designed by her. It is significant that in the whole play, she is referred to by name nineteen times in total-- the majority of the time, she is Polonius’ daughter, Laertes’ sister, or merely â€Å"she† or â€Å"her.† Ophelia’s first two lines are questions, but not of the â€Å"To be or not to be† variety. â€Å"Do you doubt that?† and â€Å"No more but so?† (I.3.4-9) imply a state confusion, insecurity, and disorientation-- of â€Å"blinkered† experience, of externally-imposed tunnel vision that leads to a staggering, stilted walk through life. From her first entrance, we are presented with ... ... ultimate act of self-assertion. For not only is she shaming the court and her family, talking in riddles to the brother who preached to her, and acting out to an extreme the lesson constantly reiterated by her father, the inability to live without his guidance. She is not merely distorting the pastoral â€Å"green girl† image, making a gruesome picture of the carefree, virginal â€Å"Rose of May.† She is spitting in the face of the God who placed her in such an impotent position in the first place. And this is the real tragedy of Ophelia’s life and death. Because while Hamlet dies with the knowledge that he has fulfilled his mission, Ophelia has no mission. Her first independent act, what ought to denote the beginning of a life composed of her own initiatives, is the truncating of that life. Her beginning is her end-- the house pet, released into the wild, withers and dies.