What is a Membrane Essay Example for Free

What is a Membrane Essay 1. What is a membrane? Membrane is any delicate sheet that separates one region from another blocking or permitting (selectively or completely) the passage of substances. The skin, for example, can be considered a membrane that separates the exterior from the interior of the body; cellophane, used in chemical laboratories to separate solutions, acts as a membrane too. 2. Concerning their permeability how are membranes classified? Membranes can be classified as impermeable, permeable, semipermeable or selectively permeable. An impermeable membrane is that through which no substance can pass. Semipermeable membranes are those that let only solvents, like water, to pass through it. Permeable membranes are those that let solvent and solutes, like ions and molecules, to pass across it. There are also selectively permeablemembranes, i.e., membranes that besides allowing the passage of solvent, let only some specific solutes to pass while blocking others. 3. What is diffusion?  Diffusion is the spreading of substance molecules from a region where the substance is more concentrated to another region where it is less concentrated. For example, during the boiling of water in a kitchen gaseous water particles tend to uniformly spread in the air by diffusion. 4. What is meant by concentration gradient? Is it correct to refer to â€Å"concentration gradient of water†? Concentration gradient is the difference of concentration of a substance between two regions. Concentration is a term used to designate the quantity of a solute divided by the total quantity of the solution. Since water in general is the solvent in this situation it is not correct to refer to â€Å"concentration of water† in a given solution. 5. What is the difference between osmosis and diffusion?  Osmosis is the phenomenon of movement of solvent particles (in general, water) from a region of lower solute concentration to a region of higher solute concentration. Diffusion, on the other hand, is the movement of solutes from a region of higher solute concentration to a region of lower solute concentration. 6. What is osmotic pressure?  Osmotic pressure is the pressure created in an aqueous solution by a region of lower solute concentration upon a region of higher solute concentration forcing the passage of water from that to this more concentrated region. 7.Can solutions with the same concentration of different solutes have different osmotic pressures? The osmotic pressure of a solution does not depend on the nature of the solute, it depends only on the quantity of molecules (particles) in relation to the total solution volume. Solutions with same concentration of particles even containing different solutes exert the same osmotic pressure. 8. How are solutions classified according to their comparative tonicity? Comparative to another, a solution can be hypotonic (or hyposmotic), isotonic (or isosmotic) or hypertonic (or hyperosmotic). When a solution is less concentrated than another the adjective hypotonic is given and the more concentrated is called hypertonic. When two compared solutions have the same concentration both receive the adjective isotonic. So this classification makes sense only for comparison of solutions. 9.Concerning permeability what type of membrane is the cell membrane?The cell membrane is a selectively permeable membrane, i.e., it allows the passage of water and some selected solutes. 10.What are the basic constituents of the cell membrane?  The cell membrane is formed of lipids, proteins and carbohydrates. The membrane lipids are phospholipids, a special type of lipid to which one extremity a phosphate group is bound thus assigning electrical charge to this region of the molecule. Since phospholipids have one electrically charged extremity and a long neutral organic chain they can organize themselves in two layers of associated molecules: the hydrophilic portion (polar) of each layer faces outwards in contact with water (a polar molecule too) of the extracellular and the intracellular space and the hydrophobic chains (non polar) face inwards isolated from the water. Because this type of membrane is made of two phospolipid layers it is also called a bilipid membrane. Membrane proteins are embedded and dispersed in the compact bilipid structure. Carbohydrates appear in the outer surface of the membrane associated to some of those proteins under the form of glycoproteins or bound to phospholipids forming glycolipids. The membrane carbohydrates form the glycocalix of the membrane.

Role Of SMEs In The Mauritius Tourism Industry

Role Of SMEs In The Mauritius Tourism Industry Jones and Haven- Tang (2005) studied 10 characteristics that are popular for SMEs: SMEs are job opportunities generator; there is the risk of business failure; SMEs are more flexible than are large enterprises and small entrepreneur are have a closer relationship with their customers however not too proactive to innovation and technology; motivations of SMEs depends on the entrepreneurs way of living and even differentiate through gender; business strategies differs from one SMEs to another some are well managed some are deficient in business and managerial skills; entry of business is easy but preparations in surviving depends on owners abilities to manage; SMEs are resistant to external assistance due to cultures of self reliance that act like barriers; owners are resilient to invest in managerial trainings; SMEs have poor market research and knowledge management about customers; thare are lack of an integrated approach to business planning and functionality. According to Beyene (2002) entrepreneurship is a function of opportunities, technical and commercial skills, entrepreneurial spirit, finance, infrastructure and the overall environment within which the SMEs operate. Studies (Brigham and Smith, 1967; Walker, 1975) stated that SMEs tend to be riskier than the larger organization. Cochran (1981) found SMEs were subject to higher failure rates, and Markland (1974) suggested that SMEs tend to keep less adequate records than big companies. World Bank (1994, 2002, 2004 cited Beck et al., 2003) state 3 core characteristics of SMEs which are firstly, SMEs enhance competition and entrepreneurship and hence have external benefits on economy-wide efficiency, innovation, and aggregate productivity growth; secondly, SMEs are generally more productive than large firms; and thirdly, SME boosts employment more than large firm because SMEs are more labour intensive. Dagmar Recklies (2001) stated SMEs are characterized by factors like size of enterprise or independent ownership (family of small group of people). These traits may lead to disadvantages and advantages with respect to globalization shown in table1 below: Buhalis (2009) said that the tourism industry, although the largest industry in the world, is dominated by SMEs and encapsulates any varied and disparate economic sectors. Harvey and Lee (2002) described the role of SMEs as economic in East Asian Countries. SME, according to Harvey and Lee (2002), is a source of employment, innovation and creating export opportunities and act as a means to grow into larger firms. These aspects of SMEs are important prospects that will continue in the future. According to UNIDO (2006), SMEs are the driving force in industrial development. They comprise more than 90% of all enterprises in the world and are on average providing 60 to 80% of total employment, thus help to contribute to Millennium Development Goals, in particular poverty eradication and developing global partnerships. Migiro and Ocholla (2005) suggested that SMEs account for a significant share of production and employment in many countries and are directly related to poverty alleviation. While in many respects the South African economy is different from that of other countries in the continent, SMEs are relevant for employment and as an income source. In country after country, statistics show that even during these years of economic crisis and recession, the one robust sector providing economic growth, increased productivity and employment has been that of small and medium-sized enterprises, WIPO. In 130 countries, 140 million SMEs employed 65% of labour force in July 2006, World Bank (2006, cited Kotelnikov, 2007). According to Fadahunsi and Daodu (1997, cited Beyene, 2002, p.131), in Asian countries like Indonesia, Philippines, Thailand, Hong Kong, Japan Korea, India and Sri Lanka, 90% of businesses are small enterprises and this represent 98% of the employment in Indonesia, 78% in Thailand, 81% in Japan and 87% in Bangladesh. The tourism industry of Australia primarily consists of SMEs, with more than 90% of businesses employing fewer than 20 staff, OECD. According to the European Commission SMEs play a central role in the European economy. They are a major source of entrepreneurial skills, innovation and employment. In the enlarged European Union of 25 countries, some 23 million SMEs provide around 75 million jobs and represent 99% of all enterprises. Duarte (2004) stated that the role played by SMEs in any society is undoubtedly important, for instance, in Portugal around 98% of the industrial fabric is composed by SMEs. Duarte (2004) describes the role of SMEs as an engine of economic growth and the proportion of SMEs in the industry is large in percentage. Shumpeter (1934, cited Duarte, 2004) emphasizes the role of SMEs as a principal cause of economic development. Lukasc (nd) studied that SMEs are recognized as the backbone of the British economy, accounting for more than half of the UKs turnover. 93 % of all European enterprises have less than 10 employees and there are 20.5 million enterprises in the European Economic Area (EEA) and Switzerland, providing employment for 122 million people. Alistair et al. (2003) studied the role of SMEs in China and stated that SMEs are important as they contribute to the national income and employment. Jones and Haven- Tang (2005) described the role of SMEs in developing a tourism destinations image and service quality along with other stakeholders of the industry (especially government). They described the contributions of tourism SMEs in defining service quality and thus exploring the relationship between quality of services and products by local SMEs and destination competitiveness. Jones and Haven- Tang (2005) explained that the nature of tourism SMEs makes it important for policy makers to consider in order promoting destination development. Andersson et al (2007) discussed the role of SMEs owned by women as contributing in job creation. The authors stated that women entrepreneurs are more likely to employ women, thus providing jobs not only for themselves but for other women, which helps to reduce the effect of discrimination against women in the labour market. In addition, reducing female unemployment assists in fighting women trafficking. Finally, female entrepreneurs serve as role models for the younger generations, demonstrating new employment (self-employment) opportunities. According to UNIDO (2003) the only way to reduce poverty in a sustainable way is to promote economic growth, through wealth and employment creation. In developing countries, SMEs are the major source of income, a breeding ground for entrepreneurs and a provider of employment. SMEs may be characterized as the principal building blocks of the Pakistani economy, providing the country with opportunities for increased employment (including female employment), poverty eradication, enhanced productivity, competitiveness and international market penetration. Kotelnikov (2007) studied the contributions of SMEs to employment and the countries GDP and innovations. It is commonplace for governments to have policies to encourage the growth of SMEs as they can help to directly alleviate poverty by increasing income levels and creating jobs. Kotelnikov (2007) stated that SMEs encourages technological progress and benefit either as producers of ICT or as users of ICT for purposes such as increased productivity, faster communications and reaching new clients. As TSMEs increases, entrepreneurs become more aware of the managerial skills as well as knowledge of the industry expands resulting into innovation of their products and services thus gaining a competitive advantage to increase profits thus encouraging people to invest to establish TSMEs because of the market opportunities captured by the profitability. He described SMEs as efforts to develop women entrepreneurship that helps in return in increasing gender equality by providing women with a source of income. Manyara and Jones (2005) describe the importance of the TSMEs development in Kenya that can help in the goal of alleviating poverty and developing of new tourism product. Sustainable livelihoods are considered to be possible through SMEs in the tourism industry and the authors explained the economic impact of SMEs on the poverty alleviation. They consider tourism SMEs to benefit local communities and creation of SMEs will enable better linkage with the local economy and will support complementary partnerships. Di Dominico (2005) studied the concept of lifestyle entrepreneur that is the non-economic factors of TSMEs. She describes the non-economic business values and orientations like the lifestyle of small business owners. Establishing a small enterprise may not have same significance to different people. Different person belonging to different groups have different aims and objectives in mind while setting up a business. People have incentives according to their social, economic and cultural environment in which they live. Some people start a business to be their own boss, and not be controlled by other person. Therefore people have different motivations like liberty and independence other than economic ones like profitability to start forming small businesses defining a way of living or lifestyle. The author analysed that lifestyles of SMEs reflect a less objective definition of quality of life that consider aspects of work, family, gender and variations of consumption and the relationsh ip between these aspects. However, she added that in TSMEs there must be a more objective approach to ownership and management in order to have development and success. Baldwin (1995) studied the characteristics of SMEs that make success possible. He talked about innovation being the prime factor that contributes to success. The use of proper technological, marketing, management, human resource, investment and competitive strategies are necessary to increase or decrease profitability. Theses factors are the growth factors associated to success. The study shows that SMEs stress the importance of management. SMEs focus on often stated problems in the area of training, capital cost and innovation. TSMEs are conscious of the need for a highly-skilled work force and rank themselves above their competitors in this regard. He stated that successful SMEs have to consider three dimensions that are growth, profitability and productivity. The best way to achieve these dimensions according to Baldwin (1995) is by innovation. According to Migiro and Ocholla (2005), SMEs and ICT have a direct connection in improving the business efficiency, productivity and the development of new products and services, thus creating new business opportunities and markets. The use of technology is widely used in marketing, advertising, doing transaction with foreign clients and adopting the concept of e-commerce. ICT have a role in improving business services, as in the hotel and tourism industry (Duncombe and Heeks, 2001, cited Migiro and Ocholla, 2005). Chandra (2002) stated that SMEs have to go through the technology ladder in order to remain competitive. Lal (2007) studied the adoption of ICT in the Nigerian SMEs. According to him, globalization is among the factors that influence SMEs to make use of technologies. However, he explains that good electricity supply and connectivity is necessary for SMEs to make use of IT. E-Commerce is one of the most visible examples of the way in which ICTs can contribute to economic growth. It helps countries into the global economy. It allows business and entrepreneurs to become more competitive. And it provided jobs, thereby creating wealth (UNCTAD 2004a, cited Lal 2007). However, the human capital should not be ignored as Cunningham and Rowley (2008) studied the role of SMEs in China and a system of HRM that will boost competitive capabilities of SMEs. They stated that SMEs acts as non-governmental investment booster while contributing to the improvement of the economic structure. Hence, SMEs play an important economic role in China. The traditional personnel practices of SMEs should shift to HRM, which are resourcing, rewards, development and relations, and to more management dimensions. Proper management skills as well as considering other factors such as an organizational strategy and taking account of the national context are necessary for sustaining growth, prospects and ultimately survival.

American Antislavery 1820-1860 :: History African Americans Essays

American Antislavery 1820-1860 missing works cited The antebellum American antislavery movement began in the 1820s and was sustained over 4 decades by organizations, publications, and small acts of resistance that challenged the legally protected and powerful institution of slavery and the more insidious enemy of black equality, racism. Abolitionists were always a radical minority even in the free states of the North, and the movement was never comprised of a single group of people with unified motivations, goals, and methods. Rather, the movement was fraught with ambiguity over who its leaders would be, how they would go about fighting the institution of slavery, and what the future would be like for black Americans. Some of the persisting goals of antislavery activism were legal emancipation, aid to runaway slaves through vigilance groups and the Underground Railroad, civil rights for freed blacks in the north, and education, suffrage, and economic advancement for African-Americans. Perhaps the most unifying ideal of the anti-slavery movement was that the racial basis for American slavery could be undermined by promoting Christian values, education and economic progress among free blacks to show that they were capable of succeeding as individuals in an integrated American society. Richard Allen, leader of the A.M.E. church, stated the case for black progress as an answer to the justifications of slaveholders: â€Å"if we are lazy and idol, the enemies of freedom plead it as a cause why we ought not to be free.† In addition to the connection between abolition and economic and social progress, most abolitionists worked for the assurance of civil rights and legal protection for free blacks, who lived in an anomalous condition of â€Å"freedom† without citizenship and with constant threat of discrimination, violence, and abduction to be sold into slavery. There were some bitter conflicts over specific strategies. Though Garrison and most blacks favored immediate abolition, many whites continued to prefer or express willingness to settle for gradual emancipation. Violent resistance was at first rejected by many, again under the influence of Garrison, but David Walker’s appeal that violence should be used against slavery became more popular as blacks and abolitionists searched for an effective means of self-defense against mobs and pursuit of civil rights. Whether or not individuals worked within the political framework of the constitution to effect change again depended on allegiance to Garrison, and in general the early antislavery activists preferred moral arguments while later leaders were more willing to use political means.

Frost :: essays research papers

Robert Frost: Biography and Review   Ã‚  Ã‚  Ã‚  Ã‚   Robert Lee Frost, b. San Francisco, Mar. 26, 1874 d. Boston, Jan. 29, 1963, was one of the leading poets of the 20th-century and a four time winner of the Pulitzer Prize. Frost was a poet often associated with rural New England, although his poems could be felt and related to in any region of the world. Thought his younger days may have not been filled with other children having fun and such, Frost made the best of what he enjoyed. At the young age of only eleven Frost’s father passed away. Soon after his death the family left California to settle in Massachusetts. As young Frost grew-up he attended high school in that state, later would enter Dartmouth College, but would remain there less that one semester. Later he returned to Massachusetts where he would be a school teacher along with two other jobs he held as a mill worker and a newspaper reporter.   Ã‚  Ã‚  Ã‚  Ã‚  Then in 1895 Frost married Elinor White whom he had been co-valedictorians with in high school. Then between 1897 and 1899 Frost felt the need to go back to college he attended Harvard as a special student only to leave without a degree. Over the next ten years he would write more poetry. Frost would live on and operate a farm in Derry, New Hampshire that his grandfather had purchase for him with the condition he live there for a minimum of ten years. He would also take a teaching position at Derry’s Pinkerton Academy to receive another form of income. Frost would not stay there long, as he felt the need to once again move.   Ã‚  Ã‚  Ã‚  Ã‚  In 1912, when Frost was nearly forty he sold the farm and used the proceeds to take his family to England, where he could devote himself entirely to writing. Frost would establish himself quickly and would reap the awards of immediate success. In 1894 at the age of twenty Frost sold and published his first poem “My Butterfly:An Elegy'; to The Independent, a New York literary journal. This was his first step in the long line of success that he would encounter. Only a year after Frost arrived in England his book “A Boy’s Will'; was accepted and published. With the help of favorable reviews on both sided of the Atlantic a American publisher published his book. The Henry Holt and Company became Frosts primary American Publisher. Frost :: essays research papers Robert Frost: Biography and Review   Ã‚  Ã‚  Ã‚  Ã‚   Robert Lee Frost, b. San Francisco, Mar. 26, 1874 d. Boston, Jan. 29, 1963, was one of the leading poets of the 20th-century and a four time winner of the Pulitzer Prize. Frost was a poet often associated with rural New England, although his poems could be felt and related to in any region of the world. Thought his younger days may have not been filled with other children having fun and such, Frost made the best of what he enjoyed. At the young age of only eleven Frost’s father passed away. Soon after his death the family left California to settle in Massachusetts. As young Frost grew-up he attended high school in that state, later would enter Dartmouth College, but would remain there less that one semester. Later he returned to Massachusetts where he would be a school teacher along with two other jobs he held as a mill worker and a newspaper reporter.   Ã‚  Ã‚  Ã‚  Ã‚  Then in 1895 Frost married Elinor White whom he had been co-valedictorians with in high school. Then between 1897 and 1899 Frost felt the need to go back to college he attended Harvard as a special student only to leave without a degree. Over the next ten years he would write more poetry. Frost would live on and operate a farm in Derry, New Hampshire that his grandfather had purchase for him with the condition he live there for a minimum of ten years. He would also take a teaching position at Derry’s Pinkerton Academy to receive another form of income. Frost would not stay there long, as he felt the need to once again move.   Ã‚  Ã‚  Ã‚  Ã‚  In 1912, when Frost was nearly forty he sold the farm and used the proceeds to take his family to England, where he could devote himself entirely to writing. Frost would establish himself quickly and would reap the awards of immediate success. In 1894 at the age of twenty Frost sold and published his first poem “My Butterfly:An Elegy'; to The Independent, a New York literary journal. This was his first step in the long line of success that he would encounter. Only a year after Frost arrived in England his book “A Boy’s Will'; was accepted and published. With the help of favorable reviews on both sided of the Atlantic a American publisher published his book. The Henry Holt and Company became Frosts primary American Publisher.

Alice Walker Essay -- essays research papers

Alice Walker   Ã‚  Ã‚  Ã‚  Ã‚  Alice Walker is an African American essayist, novelist and poet. She is described as a â€Å"black feminist.†(Ten on Ten) Alice Walker tries to incorporate the concepts of her heritage that are absent into her essays; such things as how women should be independent and find their special talent or art to make their life better. Throughout Walker’s essay entitled â€Å"In Search of Our Mothers’ Gardens,† I determined there were three factors that aided Walker gain the concepts of her heritage which are through artistic ability, her foremothers and artistic models.   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"In Search of Our Mothers’ Gardens† touches mainly upon family heritage and the way her heritage was created. In Atwan’s Ten on Ten, you will find the essay on the Mothers’ Gardens. On page 83 it states, â€Å"For they were going nowhere immediate, and the future was not yet within their grasp.† This quote signifies how mothers and grandmothers would always be set serving the men in their lives; for their entire lives, however, there was a different future, a plan that they didn’t see yet. This plan was for them to identify their artistic ability, whether if it was through singing, writing or making quilts.   Ã‚  Ã‚  Ã‚  Ã‚  Throughout the essay, â€Å"In Search of Our Mothers’ Gardens,†Alice Walker’s mentions her foremothers. Women like Jean Toomer, Phillis Wheatley and Zora Neale Hurtson, who were all either poets or writers. Mike Fike has also reco...

Violating Social Norms Essay

Social norms are the shared expectations of what kind of behavior is acceptable and what isn’t. Violating social norms can be very amusing for the person who’s doing it, but can sometimes gather very hostile reactions from those around you. Violating personal space, standing on the wrong side of the escalator, walking on the wrong side of the sidewalk, wearing your clothes backwards and paying with change are just a few examples of how social norms can be broken. My partner Jordyn and I proved with our project that stepping outside of the box and violating social norms isn’t always as bad as it seems. For starters Jordyn and I decided we were going to violate a social norm by going to a food place and paying with change. At first I felt really awkward because I wasn’t sure how the cashier and those around us were going to react but I just went with it anyway. Jordyn went first and I filmed her, she waited in line like normal and oddly enough when she pulled out the change it really wasn’t that big of a deal for anyone. The cashier was really nonchalant about it and even helped her to count the change, it was all very casual. The results I got when it was my turn were very similar to Jordyn’s I went up and ordered my drink and when he told me the total I pulled out my change same as last time and the cashier helped me count the change, he seemed to have no problem with the fact that I was paying with change which was actually very refreshing. It didn’t feel like anyone was being judgmental and overall I just felt very comfortable with the whole situation. In conclusion violating social norms can have varying results depending on the act you’re taking part in and the people that are around you while you’re doing it. I feel that our project was very successful because we broke a social norm but we didn’t show up with all pennies which would have probably gotten a better reaction, but in my opinion would be slightly obnoxious. I know that if I were in a cashier’s position I would be pissed so we didn’t take it that far. Regardless of the type of change we paid in IÂ  think we definitely displayed a great example of violating a social norm and I’m very proud of our uniquely found success with this project.

Hamlet Moral Philosophy Essay

Throughout Hamlet there is a moral conflict in regards to suicide. As the events of the play unfold Hamlet finds himself pondering whether or not life is worth living in such a decrepit world. Uncertainty keeps Hamlet from ending the pain of life, as well as his desire for revenge on Claudius. Periodically throughout the play Hamlet stops to contemplate his mortality and ending his life. Hamlet does this in his soliloquies, often about whatever event is happening right then as well as, as is his melancholic nature, thinking about whether life is worth living. In the famous â€Å"to be, or not to be†(3.1.56) speech, Hamlet is literally weighing the options between to be, or to live, or not to be, to die, and in the end he finds that the uncertainty of death makes â€Å"calamity of so long life†(3.1.69). Speeches like this and others throughout the play are prompted by Hamlet’s distress at all of the conflicts going on around him. These speeches are Hamlet’s innermost thoughts and so are intended for Hamlet as they are his reflection on the moral conflict he is facing. Hamlet’s soliloquies reflect his inner conflict as he reflects upon whether or not he should end his life and his suffering or live and continue to suffer through his pain. In Hamlet’s soliloquy in Act 3 Scene 1, or the â€Å"to be, or not to be† speech, Hamlet uses various rhetorical techniques to judge whether he should live or die. He uses imagery in this speech such as â€Å"The oppressor’s wrong, the proud man’s contumely† (3.1.71) to illustrate the pains which may be felt in the sleep of death which he is considering. Hamlet also uses repetition throughout the speech to emphasize his conflict between life and death, particular in reference to sleep as he says â€Å"To die, to sleep† (3.1.60&64), he does this to highlight his uncertainty at the idea of death, or what may be lurking thereafter, â€Å"what dreams may come†(3.1.66). Hamlet’s perspective on this moral conflict changes as he finds purpose in his revenge against Claudius and begins to see his plan come to fruition. In the beginning of the play, Hamlet seems to be contemplating suicide whereas at the end, Hamlet wants to live to see his revenge against Claudius completed.