Principles of Assessment Expository of Scientific Report Writing as an Assessment Item

Free Essays on Ozone Depletion

Ozone Depletion The ozone layer is the earth’s protection against harmful ultra-violet rays that cause cancer. The ozone is a region of the earth’s atmosphere that is 12 to 30 mi above the earth’s surface. (www.encarta.msn.com) The layer of the Earth's atmosphere that surrounds us is called the troposphere. The stratosphere, the next higher layer, extends about 10–50 kilometers above the Earth's surface. Stratospheric ozone is a naturally occurring gas that filters the sun's ultraviolet (UV) radiation. (www.factmonster.com) The ozone’s job is to absorb much of the radiation that the sun gives off. There are two forms of this radiation that come from the sun: visible light and ultra-violet light. Visible light waves are the only electromagnetic waves we can see with are eyes and ultra-violet light is the radiation that humans have to protect themselves against. (http://imagers.gsfc.nasa.gov) Humans on earth are destroying the very thing that protects us and allow us to continue to live on this earth. Without our ozone all human and living things on this earth will seize to existence. To protect our home we need to evaluate the causes, the effects and the future of ozone depletion. The Cause What is the cause of our depleting ozone? It is believe to be caused by many of the things we used in our everyday lives: cars, refrigerators and aerosol cans. The ingredients that are in these items are compounds called chlorofluorocarbons (CFC), which was created in 1928 and other pollutes like halons that are used in fire extinguishers. (www.factmonster.com) When CFCs reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms, which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules. (www.greenpeace.org) Chlorofluorocarbons and these other polluta... Free Essays on Ozone Depletion Free Essays on Ozone Depletion Ozone Depletion The ozone layer is the earth’s protection against harmful ultra-violet rays that cause cancer. The ozone is a region of the earth’s atmosphere that is 12 to 30 mi above the earth’s surface. (www.encarta.msn.com) The layer of the Earth's atmosphere that surrounds us is called the troposphere. The stratosphere, the next higher layer, extends about 10–50 kilometers above the Earth's surface. Stratospheric ozone is a naturally occurring gas that filters the sun's ultraviolet (UV) radiation. (www.factmonster.com) The ozone’s job is to absorb much of the radiation that the sun gives off. There are two forms of this radiation that come from the sun: visible light and ultra-violet light. Visible light waves are the only electromagnetic waves we can see with are eyes and ultra-violet light is the radiation that humans have to protect themselves against. (http://imagers.gsfc.nasa.gov) Humans on earth are destroying the very thing that protects us and allow us to continue to live on this earth. Without our ozone all human and living things on this earth will seize to existence. To protect our home we need to evaluate the causes, the effects and the future of ozone depletion. The Cause What is the cause of our depleting ozone? It is believe to be caused by many of the things we used in our everyday lives: cars, refrigerators and aerosol cans. The ingredients that are in these items are compounds called chlorofluorocarbons (CFC), which was created in 1928 and other pollutes like halons that are used in fire extinguishers. (www.factmonster.com) When CFCs reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms, which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules. (www.greenpeace.org) Chlorofluorocarbons and these other polluta...

Ancient and Medieval Political Theory Assignment

Ancient and Medieval Political Theory - Assignment Example Aquinas in the theory hypothesized the concept of nature to help society members understand that there is a supernatural being beyond this earth. Aquinas further argues that the world is merely a resting bay after which humans move to another life. This concept outstands in the Thebes society when various characters keep invoking the punishment sinners will receive from gods after death. Creon’s wife, Eurydice commits suicide cursing the husband and expressing her wish for god’s punishment upon the death of the husband. The blind prophet Tiresias brings the supernatural concept by claiming prophesies of god’s desires and anger to the king. The concepts solve the conflict between the church and the human freedom to think. It shows that the actions of the worldly authority must reconcile with the wishes of the church for harmonious coexistence. The concept of sovereignty is the source of law. Based on political ideologies and tenets, sovereignty rests with the people’s power. Based on theological points of view, however, sovereignty originates from God. It, therefore, gives individuals the freedom to make decisions without autocracy from rulers and the church. The concept of supremacy of the church also creates harmony between the church and the government. Creon, the dictator who does not obey the will of his people, chorus later comes to lament when his son Haemon and wife commits suicide for his actions. Disobedience of sovereignty attracts heavy punishment from God irrespective of who you are in the

Wireless Security Research Paper Example | Topics and Well Written Essays - 3000 words

Wireless Security - Research Paper Example On the other hand, there are countless security and privacy issues also emerging in wireless networking environments. Though, the new technologies require more and more high level application of wireless communication networks, but such implementations are being established without giving significant concentration to privacy and security related issues. Consequently, the majority of wireless networks around the world are in danger regarding security and safety. Thus, there are a lot of chances that someone with appropriate equipment could be able to spy network traffic. In this scenario, they can get access to users’ passwords and other data (Gerkis, 2006; The State University of New Jersey, 2006). In addition, these security issues and attacks are not immediately theoretical. Additionally, techniques and tools to tap near wireless networks are extensively accessible, even for palmtop devices (Gerkis, 2006; The State University of New Jersey, 2006). In this situation there is vital need for implementing wireless security. Wireless security management has turned out to be a hot issue in literature. This paper presents a detailed analysis of wireless security related issues and their management. This research will analyze some of the important aspects of wireless security, main challenges and possible mitigation techniques. TECHNOLOGY INVOLVED IN WIRELESS NETWORKS Consider the fact that users of WLAN (wireless local area network) are able to travel along with their laptop computers and other devices from one location to another inside their offices or houses without breaking the link with the network. Thus, many corporations and general public at the present think that wireless communication based devices are very useful, efficient, and easy to operate. On the other hand, personal networks based on wireless technology help users receive and distribute data, as well as software applications, by making use of network systems and other users of the network with well-matched devices, without establishing a connection to printer cables and other secondary device links. In fact, with wireless networking users of small PDA, hand-held devices and cell phones can effectively coordinate data and information among PDAs and personal computers, as well as are able to effectively make use of internet based services l ike that web browsing, email and internet access. In addition, wireless communications can help individuals and business firms reduce their networking or wiring costs (Radack, 2011; Gerkis, 2006; css-security, 2010). In this scenario, Information Technology Laboratory established by NIST (National Institute of Standards and Technology), presents various standards and measures which can be adopted to enhance safety and security of wireless communication networks. Additionally, National Institute of Standards and Technology Special Publication (SP) 800-48,  Wireless Network Security, 802.11, Bluetooth, and Hand-held Devices, whose authors were Les Owens and Tom Karygiannis, outlines 3 main and fundamental aspects of wireless security: (Radack, 2011; Ge

Introduction To E-Business Essay Example | Topics and Well Written Essays - 500 words

Introduction To E-Business - Essay Example All cross-organizational elements of the Inbound Supply Chain, including different aspects like Enquiry/RFQ details, Online and Offline Quotation logging, Order Placement, Delivery compliance monitoring, Order amendments, Material Receipt and Payment tracking are covered and also relevant transactions can be made through this e-procurement site. In addition to these new features and benefits, value-added services such as Negotiation Chat Room with Bid revision tracking (Reverse Auction), Transactional correspondence (mails initiated on a transaction hitting appropriate mailboxes) and e-Mail notifications and acknowledgements, are also offered (Tata Steel, 2004). While the site incorporates all the basic functionalities that may be required, the company is still putting in continuous effort towards providing value-added services and features. Taobao.com, China's leading consumer e-commerce website is a division of the Alibaba Group (Alibaba Group, 2007). Taobao is a shopping marketplace for consumers in China. Founded by parent Alibaba Group, it facilitates transactions between individual consumers and a wide range of sellers such as retailers, wholesalers, and other individuals.

Cell Migration And Cell Cytoskeleton Biology Essay

Cell Migration And Cell Cytoskeleton Biology Essay The cytoskeleton of a cell plays a vital role in controlling the movements of the cell. 3 types of fibres form this structure; microtubules, microfilaments and intermediate filaments. Microtubules are large hollow fibres, microfilaments are the smallest at only 6nm in diameter (1) and intermediate filaments are in between. Microtubules are formed from the subunits ÃŽ ± tubulin and ÃŽ ² tubulin, which form dimers. Each tubulin dimer contains 1 ÃŽ ± tubulin subunit and 1 ÃŽ ² tubulin subunit. These then polymerise to form long protofilaments, which join together into sheets. Once a sheet of 13 protofilaments has been formed, they then fold over to produce a hollow microtubule, which continues to elongate from the +ve end where only ÃŽ ² tubulin subunits are showing. Microfilaments are made of a protein subunit called actin. There are two types; G actin and F actin. G actin is turned in to F actin by the hydrolysis of ATP, forming a fibrous filament. The actin filament continues to elongate from the -ve barbed end. There are several types of Intermediate filaments, each made of different proteins depending on the function of the cell in which they are contained. Type I Keratins acidic and Type II Keratins basic are found in epithelial cells and in the hair and nails. Nuclear lamins are found in the nuclear lamina and type III vimentin/desmin/peripherin are found in muscle cells, some neurones and stem cells (2). The monomers form dimers by coiling. Tetramers are then formed from dimers arranged in staggered formation with opposite domains together. These then arrange together forming strong coiled filaments. Many cells move by crawling over surfaces (3). Of the three fibrous structures, explained previously that make up a cell, the microfilaments play the largest part in the movement and migration of a cell. This means that actin is the vital component for cell movement. A fibroblast crawls by a leading protrusion, called a lamellipodium, which is where most of the cells actin is located. The actin is extremely flexible due its twisted, linked structure. The filaments clump / bundle together near the cell membrane, particularly at the protrusions such as the microvilli in an intestine lining epithelial cell. The actin penetrates in to the cytoplasm, where they become cross linked in to a three dimensional meshwork, governing the shape and mechanical properties of the plasma membrane and the cell surface. (4) . This means that the actin provides structural support, as well as movement potential for the cell. Filopodia are very similar to lamellipodia. They also protrude out from the mai n body of the cells like lamellipodia, and act like fingers for the cell to feel the environment around it and also to aid the detection of where the cell is supposed to migrate to. Filopodia have almost the exact same structure as lemellipodia, however have smaller protrusions and therefore contain less actin. They are about 0.1 Â µm wide and between 5 10 Â µm long, and each contains a loose bundle of 10 20 actin filaments, orientated with their positive ends pointing outward'(5), exactly like the orientation of the actin filaments in lamellipodia. However, filopodia are present around the whole circumference of the cell, not just protruding from the lamellipodium, which creates an even larger surface area for the cell to detect its surroundings. The protrusions grow by the growth of the actin filaments, where dimers are added to the positive terminals of the filaments. Although dimers are removed from both terminals, particularly the negative end, this is outweighed by the mor e rapid addition of actin at the positive end. The growth is a very quick process, which therefore allows the cells to move around the body at a fairly fast pace. Once the lamellipodium is protruded from the main structural shape of the cell, the newly produced bottom section of the cell then adheres to the surface it is moving along, hence pulling the rest of the cell along with it. At the same time, contraction occurs at the rear of the cell, then draws the body of the cell forward, in the direction the lamellipodium is protruding, in a process called traction. (6) Cell migration is extremely important to an organisms survival. It is essential for the movement of cells in the immune system, an example of which is a macrophage, which finds destructive cells and eats them. This is because it is vital for cells to be able to travel to the site of an infection in order to fight it and clear it up or to communicate with other cells, to let them know that there is a problem, which they can then sort out. Cells that can do this are called fibroblasts, which migrate through connective tissue, remodelling them where necessary and helping to rebuild damaged structures. (7). If this was not possible, the organism would be in serious trouble and could die or be badly damaged by very superficial wounds and mild diseases which are overlooked as non-serious in humans due to cells being able to migrate. The cell migration mechanism is vital to a macrophage, as its job is to move around the body, detecting and destroying harmful cells. If movement was not possi ble, the macrophage would only be able to detect destructive cells that were situated in the immediate vicinity, which means to successfully remove all harmful pathogens would be impossible. This would mean the organism would have very little protection against disease. Cells are also able to migrate by means other than by lamellipodium protrusions. Cilia are one example, as well as a male humans sperm, which moves by a tail like structure called a flagellum. The sperm is able to beat the flagellum, which is designed to move the entire cell, and instead of generating a current, they propagate regular waves along their length that propel and drive the cell through liquid (8). Unlike most other migrating cells in the human body as described above, the main component for movement in flagella is tubulin. Microtubules span the whole length of the flagellum in an axoneme, which contains two central microtubules that are surrounded by an outer ring of nine pairs of microtubules. (9). The movement is enabled by molecules of ciliary dyenin that form bridges between neighbouring microtubules around the circumference of the axoneme. (10) The end tail of one molecule attaches to a microtubule, while its other end, the head of the molecule attaches to another m icrotubule. This promotes a sliding mechanism similar to that of actin in the migration of cells with lamellipodium protrusions. Bacteria and cilia also have flagella, made of flagellin and dynein. The bacterial flagellum has a similar structure to a microtubule in the way that it is a hollow, tube like shape. Ciliary beating can either propel single cells through a fluid or can move fluid over the surface of a group of cells in a tissue (11). The second is apparent in the human respiratory system, where ciliated respiratory epithelium cells in the trachea prevent any foreign, potentially harmful particles such as dust and bacteria in the air from entering the bronchioles and lungs. They do this by acting like tiny hairs and by beating the saliva containing the harmful particles back up the trachea to exit the nasal cavities by coughing. If the cilia are unable to beat, it causes problems such as Kartageners syndrome or primary ciliary dyskinesia. Although this syndrome is extremely rare, it is a genetic disorder, meaning it is hereditary. Due to the respiratory system having little to no defence against dust and pathogens which enter the nasal cavities and then travel down the trachea and bronchi, harmful particles may enter the lungs. This causes infection and disease of the lungs, such as pneumonia or bronchitis. In conclusion, the presence of cell migration mechanisms in organisms as small as bacteria to the large, multi cellular organisms such as humans is extremely vital to their individual survival. Without such an important ability, cells would not be able to detect or fight disease, from minor superficial impediments to very serious illnesses. Reproduction in humans would not be possible and bacteria would find it extremely difficult to invade host cells for reproduction. Without cell migration, the whole human immune system would not be able to function correctly. Although the movement of cells is quite complex, it is only the beginning of a massive sequence of mechanisms in which cells can communicate with each other to orchestrate the correct workings of the human body.

The Changing Role of Human Resources :: Human Resources Essays

Introduction In most companies today, the HR function provides vital services to such stakeholders as job applicants, workers, supervisors, middle managers, and executives. Yet, the HR function tends to be located at the end of the business chain, on the reactive side, and too frequently centers on carrying out actions rather than achieving outcomes. The role of the HR function is frequently one of providing people, training, and secluded HR efforts after others have formulated organizational strategy and have initiated operational accomplishment. Cost centered management of worker benefits programs such as health insurance, workers' compensation, and pension plans have also figure outstandingly in an effort to control out of control operating costs (Dunn, 2006). Discussion The HRM department at our company does not really play a strategic role in the organization. Presently they spend the majority of their time doing the day to day things like hiring people, training, and other HR efforts that allow the business to function everyday. In order for business to achieve success in the every changing business world it is important for HR departments to become more strategically aligned with the overall goals and efforts of companies. There are three key reasons why businesses are changing their methods. The first is reducing costs. HR departments should no longer want to be seen as just a support function and cost center, they need to show their value. Secondly, it is the competitiveness of business today and the fight to employ and retain people that will help drive the business. Finally, HR departments are now expected to have an understanding of how other departments function in order to make a valuable contribution to the whole of the business (Brockway, 2007). The HR professional who will succeed in guiding their organizations into the future will be those who understand and use business strategy; understand corporate culture, plans and policies; recognize future problems and work solutions; can deal with all types of people; can communicate well verbally and in writing; and can recognize, recruit and train future executives. As organizations continue to move towards collective systems and combined financial resources for managing their human capital, we are likely to see more organizational structures combining both HR and Organizational Development (OD). The time has come to quit debating OD's involvement in HR systems and seek the present opportunities of showcasing the skills of OD in building organizational capacity and having a measurable impact on workforce productivity.