Wide Area Network (WAN)

Types and Characteristics of WANs

What is a WAN?

There are two prevailing definitions of a Wide Area Network (WAN). The book definition of a WAN is a network that spans large geographical locations, usually to interconnect multiple Local Area Networks (LANs). The practical definition of a WAN is a network that traverses a public network or commercial carrier, using one of several WAN technologies

What are its Main Components?

The main components for a WAN are routers, switches and modems. These components are described below in the hardware section.

CPE – Devices on the subscriber premises are called customer premises equipment (CPE).

The subscriber owns the CPE or leases the CPE from the service provider. A copper or fiber cable connects the CPE to the service provider’s nearest exchange or central office. This cabling is often called the local loop, or “last-mile”.

DTE/DCE – Devices that put data on the local loop are called data circuit-terminating equipment, or data communications equipment (DCE). The customer devices that pass the data to the DCE are called data terminal equipment (DTE). The DCE primarily provides an interface for the DTE into the communication link on the WAN cloud.

Hardware

In a WAN you will need various types of hardware components for it to function. The typical items of hardware that you will need in a WAN are:

Router – An electronic device that connects a local area network (LAN) to a wide area network (WAN) and handles the task of routing messages between the two networks. Operates at layer 3, and makes decisions using IP addresses.

Switch – A switch is a network device that selects a path or circuit for sending a unit of data to its next destination. Operates at layer 2, and uses MAC addresses to send data to correct destination.

Modem – Short for modulator/demodulator, a modem enables a computer to communicate with other computers over telephone lines. Operates at layer 1, where signals are converted from digital to analogue and vice versa for transmission and receiving.

Wan Standards

WANs operate within the OSI model using layer 1 and layer 2 levels. The data link layer and the physical layer. The physical layer protocols describe how to provide electrical, mechanical and functional connections to the services provided by the ISP. The data link layer defines how data is encapsulated for transmission to remote sites.

Encapsulation

Encapsulation is the wrapping of data in a particular protocol header. Remember that WANs operate at the physical layer and the data link layer of the osi model and that higher layer protocols such as IP are encapsulated when sent across the WAN link. Serial interfaces support a wide range of WAN encapsulation types, which must be manually specified. These types include SDLC, PPP, Frame delay etc. Regardless of WAN encapsulation used it must be identical on both sides of the point to point link.

Packet and Circuit Switching

Circuit switching and packet switching are both used in high-capacity networks.

The majority of switched networks today get data across the network

through packet switching.

Circuit-switching is more reliable than packet-switching. Circuit switching is old and expensive, packet switching is more modern.

General Routing Issues

What is a Routing Protocol?

A routing protocol is a protocol that specifies how routers communicate and exchange information on a network. Each router has prior knowledge of its immediate neighbours and knows the structure of the network topology. The routers know this because the routing protocol shares this information.

Protocol

RIP (Routing Information Protocol) was one of the most commonly uses protocols on internal networks. Routers use RIP to dynamically adapt changes to the network connections and communicate information about which networks routers can reach and the distance between them. RIP is sometimes said to stand for Rest in Pieces in reference to the reputation that RIP has for breaking unexpectedly and rendering a network unable to function.

Routing Algorithms

Distance Vector

This type of routing protocol requires that each router simply inform its neighbours of its routing table. The distance vector protocol is also known as the bellman-ford algorithm.

Link State

This type of routing protocol requires that each router maintain a partial map of the network. The link state algorithm is also know as Dijkstra’s algorithm.

IGRP

IGRP is a type of distance vector routing protocol invented by cisco used to exchange routing data in a autonomous system. Distance vector protocols measure distances and compare routes. Routers that use distance vector must send all or a portion of their routing table in a routing update message at regular intervals to each neighbour router.

Addressing and Routing

What does routing mean?

Routing is the process of deciding how to move packets from one network to another.

The directions also known as routes can be learned by a router using a routing protocol then the information is passed from router to router along the route of the destination.

IP Address’s

Every machine connected to the internet is assigned an IP address. An example of an IP address would be 192.168.0.1. IP addresses are displayed in decimal format to make it easier for humans to understand but computers communicate in binary form. The four numbers that separate an IP address are called Octets. Each position consists of eight bits. When added to together you get 32 bit address. The purpose of each octet in an IP address is to create classes of IP addresses that can be assigned within a network. There are three main classes that we deal with Class A, B and C. The octets of an IP address are split into two parts Network and Host. In a class A address the first octet is the network portion, this determines which network the computer belongs to, the last octets of the address are the hosts that belong to the network.

Sub netting

Sub netting allows you to create multiple networks within a class A, B or C address. The subnet address is the address used by your LAN. In a Class C network address you would have a subnet mask of 255.255.255.0. A subnet mask identifies which portion is network and which is host. For example 192.168.6.15 the first octet three octets are the Network address and the last octet being the host(Workstation). It is important to subnet a network because gateways need to forward packets to other LANS. By giving each NIC on the gateway an IP address and a Subnet mask it allows the gateways to route packets from LAN to LAN. Once the packet arrives at its destination, the gateway then uses the bits of the subnet portion of the IP address to decide which LAN to send the packets.

Circuit Switched Leased Lines

A circuit switched network is one that establishes a dedicated circuit (or channel) between nodes and terminals before the users may communicate. Here are some terminologies associated with a Circuit switched network.

Frame relay is a telecommunication service designed for cost-efficient data transmission between local area networks (LANs)

Basic rate interference is a service used by small business for internet connectivity. An ISDN BRI provides two 64 Kbps digital channels to the user.

Primary rate interface (PRI) is a telecommunications standard for carrying voice and data transmissions between two locations

All data and voice channels are ISDN and operate at 64kbit/s

Packet Switching

http://www.raduniversity.com/networks/2004/PacketSwitching/main.htm – _Toc80455261

Packet switching refers to protocols in which messages are broken up into small packets before they are sent. Each packet is then transmitted over the Internet. At the destination the packets are reassembled into the original message. Packet switching main difference from Circuit Switching is that that the communication lines are not dedicated to passing messages from the source to the destination. In Packet Switching, different messages can use the same network resources within the same time period.

http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and protocolwhich encodes data into small fixed-sized cells.

ISDN is used to carry voice, data, video and images across a telephone network. ISDN stands for integrated services Digital Network. Isdn also provides users with a 128kbps bandwidth. This is done through frame relay. Frame relay complements and provides a service between ISDN, which offers bandwidth at 128 Kbps and Asynchronous Transfer Mode which operates in somewhat similar fashion to frame relay but at speeds from 155.520 Mbps or 622.080 Mbps. Frame relay is based on the older X.25 packet switching technology and is used to transmit analogue signals such as telephone conversations.

PSDN stands for packet switched data network and is a data communication network. Packet switched networks do not establish a physical communication signal like the public telephone does (circuit switched network) Packets are sent on a fixed length basis and assigned with a source and a destination address. The packets then rely on the routers to read the address and route the packets through the network.

Mobile and Broadband Services

Digital Subscriber line(DSL) is mainly used to bring high bandwidth connections to homes and small business’s over a copper wire telephone line. This is can only be achieved if you stay within the range of the telephone exchange. DSL offers download rates of up to 6mbps allowing continuous transmission of video, audio and 3D effects. DSL is set to replace ISDN and compete with the cable modem in providing multimedia to homes. DSL works by connecting your telephone line to the telephone office over copper wires that are twisted together.

Asymmetric Digital Subscribers Line is most commonly used for home users. It provides a high download speed but a lower upload speed. Using ADSL, up to 6.1 megabits per second of data can be sent downstream and up to 640 Kbps upstream.

http://en.wikipedia.org/wiki/Symmetric_Digital_Subscriber_Line

Symmetric Digital Subscriber Line is a digital subcriber line which runs over one pair of copper wires. The main difference between ADSL and SDSL is the difference in upload and download speeds. SDSL allows the same upstream data rate and downstream data rate as ADSL upstream can be very slow.

[http://searchnetworking.techtarget.com/sDefinition/0],,sid7_gci558545,00.html

HDSL High bit-rate Digital Subscriber Line, one of the earliest forms of DSL, is used for wideband digital transmission within a corporate site and between the telephone company and a customer. The main characteristic of HDSL is that provides equal bandwidth in both directions.

IDSL is a system in which data is transmitted at 128 Kbps on a regular copper telephone line from a user to a destination using digital transmission.

The Local Loop enables operators to connect directly to the consumer via copper local loops and then add their own equipment to offer broadband and other services. This process involves operators accessing local exchange buildings to connect to a network of copper lines which connect them to homes and businesses. BT is an Example of a Local Exchange. The local loop connecting the telephone exchange to most subscribers is capable of carrying frequencies well beyond the 3.4 kHz upper limit.

Benefits of using DSL

DSL can provide virtually instantaneous transmission of voice, data and video over ordinary copper phone lines. A DSL connection can eliminate delays when waiting to download information and graphics from the Internet. It provides users with a cost effective high speed Internet connection. Another benefit is that a DSL connection is always on-line (like a LAN connection) with no waiting time for dialling or connecting.

There are now more than 10 million broadband connections in the UK. By December 2005 there were 9.792 million broadband connections in the UK and the average broadband take up rate during the three months to December was more than 70,000 per week.

A Few Fantastic Health Benefits of Yoga

There are so many of us who inevitably end up associating yoga with its “physical” attributes. In fact, they shy away from it simply thinking that yoga is strictly meant for the physically fit or the athletic ones. A highly erroneous notion. The concept is far from truth-very far! Yes, it’s a physical exercise. No doubt about it. However, one needs to understand that this ancient practice entails much more than just “body”- yogis aim for that perfect realm of stability where the mind, body and spirit work in cohesion. Today, we will be primarily discussing the health benefits of yoga but not before clearly pointing out that you can practice it even if you are not athletic! Here’s what you need to find out about the health benefits of yoga. They are simply fantastic.

It can bolster the function of lungs

Deep purposeful breathing is a part of the yogic experience. Such exercises, as per studies, can actually improve the functioning of lungs. With a better-functioning pair of lungs you can expect to perform a lot of activities better – like running or walking long distances without getting tired.

Exercises bolster the condition of your heart as well

Patients with high blood pressure and cholesterol can benefit a lot from yogic exercises. Studies, for instance, have shown that individuals practicing yoga on a regular basis have lower blood cholesterol levels and reduced risks of blood cholesterol level. What more? The efficaciousness of the breathing exercises is now even harnessed by doctors to address heart ailments. Medical practitioners duly acknowledge the usefulness of the right breathing techniques and exercises when it comes to reversing symptoms of several stress induced diseases or heart ailments.

These exercises help you master the right postures

The importance of sitting, working and walking in the right posture is mostly undermined by us. We often fail to identify the evils of wrong postures. For instance, we just fail to realize that wrong postures can actually give birth to a number of problems including neck pain, shoulder pain and so much more.

Practicing yoga can help you build stronger muscles so that they can support the right postures. Yogic exercises also add flexibility to your body thereby eliminating muscle tension so that you are able to walk and sit with your shoulders straight. You can sit with your stomach tucked in as well.

Yoga can also help you fight depression

Meditation or relaxation exercises can help you get out of depressive thoughts as well. For many depressed people, when every measure fails, yoga turns out to be the answer.

So, what exactly are you waiting for? It doesn’t matter how old you are or how athletic (or not) you are, you can always trust the therapeutic benefits of yoga in a major way. Find a credentialed instructor and get going! Make sure you are exploring more about these exercises and their benefits by reading up about the same. There is no dearth of resources to help you there. Make sure you’re keeping these points in view.

Investing 101: Before You Start Investing Money

Doesn’t it make sense to learn to invest (some basics) before you start investing money for real? Maybe a course called investing 101 or personal investing would be helpful. Here this retired financial planner relates a story, and then points the new investor in the right direction so he or she does not start investing uninformed.

In the dean’s office of one of the largest universities in America, I recently asked if they offered investing 101, personal investing, or any finance course where the student could learn to invest. “After all, we all need to start investing money someday, and it is much to one’s advantage to be informed vs. uninformed, isn’t it?” That was my response when told, “no, or at least I can’t find one” by the dean. I was informed that they had well over 50,000 current students enrolled and offered THOUSANDS of courses in the various colleges throughout the university. But he could find no course under the heading of personal investing or investing 101, and he was in charge of the curriculum.

We spent about an hour together searching and were both laughing out loud at what WAS offered. How about a course in “the art of falling down”? It’s offered. Investing 101? Which college in the university would offer such a course? “The athletic department is real big here; maybe they could help”, I suggested. After all, professional football players make big money. They need to learn to invest money (in case their career is short) and should start investing early. I knew a few players when I was a financial planner, but like most folks they tend to procrastinate when the money is flowing in. They’re too busy earning it, and don’t have the time to learn to invest.

The truth of the matter is that I don’t find it funny that it’s difficult to find a down-to earth practical course that most people could truly benefit from, because as a new investor you need to learn to invest money before you start investing for retirement or any other financial goal. As a new investor you may not be able to find a financial planner you can work with or afford. Even if you found one, do you really want to start investing money with him or her without first getting your feet wet in the basics of personal investing? Let’s start at the beginning.

Before you get into financial concepts like asset allocation and strategy, you should first learn the very basics: investment characteristics. How can you compare various alternatives to determine which best suit your needs, financial goals and comfort level? In other words, you need to decide what you are really looking for. And you need a list of factors to consider before you start investing money. For example, do you have a long term goal like retirement, and are you willing to accept a moderate level of risk? If so, there are numerous investment alternatives to consider, and you can also get tax breaks.

On the other hand, if you have a shorter term financial goal and might need access to your money at a moment’s notice, that’s a totally different picture. You need to match your financial wants and needs to the various alternatives that have characteristics best suited to your personal investing goals. There is no single best choice for every financial goal. It’s a matter of give and take. I have a list of 5 factors you must consider and a few other things you should consider before making a decision. This is basic investing 101. Whether you are a new investor or you’ve been at it for a while and have never really taken the time to learn to invest – you should learn the basics.

This is the first in a series of investing 101 articles I plan to write. In my next article I plan to put my list of characteristics you need to consider before you start investing money in black and white. Don’t feel bad if you are an uniformed new investor (or a want to-be). Do something and learn to invest starting with the basics.

Once you have a handle on a few basic financial concepts you can start investing with confidence. Once you learn to invest you can reach your financial goals. If you think I’m trying to build your confidence, you are right. Stay tuned to investing 101 as we get back to basics. No offense to anyone at one of THE largest universities in the country, but there’s a void out there and I plan to fill it.

Five Things You Will Want to Know About the Honda CR 500

If there ever was a member of the Honda CR series that was popular, then it has to be the Honda CR 500. This, by the way, is the same machine that Robbie Knievel used for his entire jumping career, which featured an astonishing twenty world records. It is still remains a popular machine, the fact that its production was stopped by Honda, as did the production of the entire Honda-CR series. As such, many people continue to search for information regarding the Honda CR 500. And if you happen to be one of these, then you will find our discussion on ‘five things you will want to know about the Honda-CR 500’ interesting.

1) One of these things you could want to know about the Honda CR 500 is its engine power. This is something that motorcycling enthusiasts are very keen about, a factor on whose strength alone many have been known to make significant purchasing decisions. As it turns out, the engine power of the Honda-CR 500 (at 491 cc) maxes at 69 Horse Power – at 8,500 revolutions per minute, quite remarkable power by any stands.

2) The second thing you may want to know about the Honda CR 500 is about its transmission. As it turns out, the Honda CR 500 comes with a complete five-speed gear box. This is a remarkable feature, for a machine that was first developed in the 80s – and considering that there are ‘modern’ motorcycles that are yet to attain the complete five gear speed transmission up to this date.

3) The third thing you may want to know about the Honda-CR 500 is about its suspension, especially if you are a person who cares about the ‘comfort of your rides,’ as do many people. As it turns out, the Honda CR 500 comes with a complete and refined suspension, a remarkable thing, seeing that many motorcycles come with what can only be described as ‘crude’ suspension: whose effects the users are left to contend with.

4) The fourth thing you may want to know about the Honda-CR 500 is about the colors it comes in, especially if you are a person who cares about aesthetics – as every proper person is supposed to. Now although the Honda CR 500 came only in flash red when it was first released in 1984, it has evolved over time (color-wise), so that today, we have it coming in many literary ‘hot’ colors: flash red, the so-called nuclear red and the so-called fighting red. So, Honda-CR 500 mainly comes in red, but different hues of it for variety.

5) The fifth thing you may want to know about the Honda CR 500 is regarding what led to the discontinuation of its production by Honda. As it turns out, the reasons were mainly environmental, and not mechanical (or to do with popularity), as one would imagine. Yet in spite of the discontinuation of its production, Honda-CR 500 remains a much-loved machine, with strong sales on the specimens of it that are still on the market, and the pieces of it that emerge on the ‘second hand motorcycles’ market every now and then.

An Introduction To Birth Control

The dictionary defines birth control as “a regimen of one or more actions, devices, or medications followed in order to deliberately prevent or reduce the likelihood of a woman becoming pregnant.” Birth control has become imperative in today’s world, due to the global rise in population, need for family planning and also to safeguard oneself from unwanted pregnancy.

There are various methods of birth control that one can adopt, including the withdrawal method, or coitus interruptus; barrier methods like condom, diaphragm, cervical cap or contraceptive sponge; chemical methods like contraceptive pills, contraceptive patch, or the progesterone-only pill (POP); intrauterine methods; fertility awareness methods and more. Other than the preventive methods, one can also adopt abortion methods like surgical abortions, chemical abortions and herbal abortifacients to end unwanted pregnancies. Some permanent birth control solutions are surgical sterilization, which includes tubal ligation for women and vasectomy for men.

Although there are many alternate methods of birth control available in the market, the most commonly used methods are contraceptive pills and condoms. Contraceptive pills or oral contraceptives consist of a pill with doses of synthetic hormones like progestin or estrogen, taken orally by a woman to prevent pregnancy. The contraceptive pills are considered to be a reliable mode of preventing pregnancy, but can sometimes also result in certain side effects like obesity, headaches or depression in some women. Condoms were traditionally manufactured for men but now are available for female users. Condoms serve a dual function, as they not only help in avoiding pregnancy but also prevent sexually transmitted diseases like HIV/AIDS.

In Canada and the US, contraceptive patches are also fast gaining popularity. A woman applies contraceptive patches on her skin for a week, and they release synthetic hormones to prevent pregnancy. They act in the same manner as contraceptive pills. Contraceptive patches in Canada and US are sold under the brand name Ortho Evra, and are sold only by prescription.

With the advances in science and technology, we might witness new innovations in birth control methods; however, in order to choose the right mode of birth control one must consult one’s doctor.

The Importance of Warming Up and Cooling Down

One of the most important factors in injury prevention is warming up and cooling down, and should not be neglected.

Warming up refers to a preparatory phase at the beginning of an exercise session. Warming up generally involves a period of low-impact exercise regimes which prepare the body for the more strenuous aspects of the sporting activity. Warming up is an important aspect of exercise in reducing the risk of injury that would possibly happen if over stretching occurred, without the person being physically warmed up and prepared for the exercise.

Cooling down refers to a short period at the end of an exercise session. The cooling down phase, again, tends to involve a short period of low-impact exercise which gradually returns the body to its ‘resting state’. The cooling down phase is believed to reduce the risk of muscular soreness which may occur the day after an exercise session, and reduce the risk of fainting or collapse after such a session.

The Warming Up Session

An exercise session should always commence with a period of warm up. In some cases it may take the form of a series of specially designed preparatory exercise, whilst in other sessions it will simply involve performing the activity at a low density before increasing the intensity to the desired level. The warming up period is important for the following reasons:

  • It gets the body ready for the physcal exertion that follows. This optimises the physical condition, enabling the body to cope more easily with the activity. It also enables the athlete to get the most benefit from the session.
  • If the warm-up session has specific movements relating to the sporting activity the muscles can be re-educated in preparation for the coming activities.
  • It reduces the risk of injury (cold muscles do not stretch very easily) and it reduces the risk of premature fatigue which can occur if the cardiovascular system is unprepared for strenuous activity.
  • It prepares cardiac function for increased activity and reduces the risk of stress being placed on the heart.

A typical warm-up may involve some ‘loosening exercises’ followed by a few minutes of low-impact aerobic activity and then a series of stretching exercises. This may last for approximately five to fifteen minutes depending upon the intensity of the session which follows. Loosening exercises at the start of the warm up may include activities such as ‘stretching’ and ‘running on the spot’. These are gentle activities which begin to prepare the body for exercise and are especially important if the athlete has been inactive for a while.

The aerobic exercise may involve activities such as cycling on an exercise cycle. This has the effect of increasing the heart rate, diverting blood to the exercising muscles and raising the overall temperature of the muscles.

Stretching exercises provide the final phase of warm up and ensure that the muscles and tendons are prepared for the exercise. An important reason for stretching exercises is to prevent the muscles and tendons from being overstretched during the session. Such a warm up will also prepare the joints for physical activity.

The Effects of Warm Up on the Body are:

  • Cold muscle, tendons and connectinve tissue do not stretch very easily. Stretching without a warm-up is therefore unlikely to produce the best effects. Warming up also relaxes the body and muscle which further allows them to be stretched effectively. It is also believed that cold muscles and tendons are more prone to damage since they are more likely to tear when cold.
  • A warm-up increases the heart rate gradually, and aerobic exercise prepares the heart and cardiovascular system, together with the muscles, gradually, for exercise.
  • A warm-up also causes the blood to be diverted to the exercising muscles. This is achieved by getting the blood vessels that supply the muscles being used, to dilate. This extra blood is diverted from areas of the body not as important for exercising, such as the gut.
  • Exercising, without warming up, may cause the muscles to work without an adequate oxygen supply. This forces them to use anaerobic processes to supplement their production of Adenosine Triphosphate (ATP). As a consequence, lactic acid accumulates and the muscles may become prematurely fatigued.

A warm-up increases the temperature of the body. This increase in temperature facilitates and speeds up many of the processes associated with exercise metabolism. It increases the rate of nerve impulse transmission, the rate of oxygen delivery to the muscles and the speed of the reactions associated with the production of ATP. Therefore, in this context, a warm up may be said to optimise the condition of the body.

Cooling Down

A cool-down involves a short period at the end of an exercise session during which the physical activity of the body is gradually reduced to almost its resting level. A cool-down therefore often involves a period of low-impact aerobic exercise which is gradually reduced, followed by a few gentle stretching exercises. This has a number of effects.

The gentle aerobic activity helps to get rid of any metabolic waste products which may have accumulated during the exercise session. The benefits of an active recovery are believed to be related to the muscles continuing to receive a more extensive supply of oxygenated blood, which will also assist with the removal of metabolic waste products.

During exercise the blood is being pumped around the body by the action of the heart. However, the blood is assisted in its return to the heart via the venous system and muscular contraction. If an athlete stops exercising suddenly, the heart continues to beat fast, sending blood around the body, but, because the exercise has ceased, the blood is no longer assisted in its return to the heart. It is suggested that this is one of the reasons why people sometimes feel faint after exercise. During a cool-down, the heart rate is gradually lowered to its resting level and the venous return continues to be assisted by the actively contracting muscles, thereby preventing this problem.

After exercising, and following the cool-down period, the athlete’s heart will still need a period of time to settle back down to its full resting rate but should be within 30 beats of what it was before the exercise session started. This will, of course, be influenced by the overall physical condition of the individual. It may also be influenced by the content of the session, with more demanding sessions requiring a more extensive cool-down. The cooling down period also provides an opportunity for the inclusion of additional stretching exercises, which may be desirable especially if they were not included as part of the main session. The inclusion of stretching exercises within the cool-down period not only helps to gradually lower the activity level of the body at the end of the session, but it may also prevent stiffness the following day.

The cool-down period is also likely to take place when the body is warm, making the muscles more receptive to stretching. The most effective stretching can therefore be performed at this time.

AIDS – What Really is AIDS and How Can it Be Prevented?

AIDS is a disease of the immune system which is caused by HIV which is otherwise known as “human immunodeficiency virus” a diagnosis of HIV can be devastating news for anyone. The condition is prolonged and takes time to weaken the immune system leaving sufferers of the illness susceptible to other illnesses such as the common cold, which due to the weakened immune system of AIDS sufferers can be deadly. An individual suffering from AIDS or HIV is also more susceptible to tumors meaning routine checkups are needed after a diagnosis, leading to a life of hospital appointments.

HIV can be transmitted through full on contact of the mucus membrane, such as mouths, lips and genitals and can also be transmitted through full on contact with an infected bodily fluid. These fluids can be blood, semen, vaginal fluid and breast milk meaning that HIV and AIDS can be passed through to a child throughout pregnancy and throughout breast feeding. The contact of these fluids can happen throughout different activities including anal, vaginal or oral sex, a blood transfusion or the exchange of infected needles, which would commonly be more associated with drug use.

AIDS symptoms often lie dormant until the disease is in its more advanced stages meaning that a diagnosis of AIDS can be even more devastating when the time left is short. Sufferers from AIDS have an increased risk of developing cervical cancer in female sufferers and cancers of the immune system such as Lymphoma. AIDS in its more advanced stage with come with symptoms such as fevers, sweats, swollen glands and weakness. Weight loss is also a common symptom of an AIDS sufferer. AIDS sufferers are also more susceptible to pneumonia as well due to the weakened immune system. AIDS is truly a life wrecking illness for everybody involved.

Since there is no cure for AIDS, the best way to decrease the spread of it and stop others contracting it is with prevention methods. Some of these methods include safe sex, being responsible and using a condom. Sexual relations are one of the main causes of AIDS transmission and a condom could save lives. It is proven that unprotected sex is responsible for the AIDS pandemic all over the world. A male or female condom would suffice.

People working in the health care industry also can do their bit in stopping the transmission of AIDS and HIV by following precautions and using the appropriate safety equipment to keep the illness from spreading. Also, it has now been said that mothers who are suffering from HIV or AIDS should avoid breast feeding their child as to prevent the child from contracting the illness as well. This is what any reasonable parent would do for their child if they knew it could save their life.

Overall, AIDS is a life wrecking disease and it is nothing to be ashamed of. Yet the prevention of it is so simple that people don’t need to be dying every day from this disease. AIDS doesn’t only affect one person; it spreads like a fire and can affect thousands. So think, and use precautions so you don’t become a sufferer too.

The Basic Principles of Preventing Infection

Basic Infection Control refers to measures designed to prevent the spread of infections or potentially infectious microorganisms to health personnel, clients and visitor. Various infection control measures are used to decrease the risk of transmission of microorganisms in hospitals.

Principles of Basic Infection Control

1. Microorganism move through space on air currents. Avoid shaking or tossing linens as these motions create currents on which these microorganisms can be transported. All isolation room doors should be closed to stop air currents.

2. Microorganisms are transferred from one surface to another whenever objects touch. When a clean item touches a less clean item, it becomes “dirty” because microorganisms are transferred to it. Keep your hands away from your hair and face. Keep linens away from your uniform. Always keep clean items separated from dirty ones, any object dropped to the floor is considered dirty.

3. Microorganisms are released into the air on droplet nuclei, whenever a person breathes or speaks. Coughing and sneezing dramatically increases the number of microorganisms released from the mouth and nose. Cover mouth when coughing and sneezing. Wash hands thoroughly.

4. Microorganisms are transferred by gravity when one item is held above another. Avoid passing dirty items over clean items or areas because it is possible for the microorganisms to drop off into a clean item or area. When storing items in a bedside stand, place a clean items on upper shelves and potentially dirty items such as bedpans on lower shelves.

5. Microorganisms move slowly on dry surfaces but very quickly through moisture. Use dry paper towel when you turn off faucets. Dry both basin before placing on bed side for storage.

6. Proper hand washing removes many of the microorganisms that would be transferred by the hands from one item to another.

Universal Precaution

1. Wear clean examination gloves for listed body fluids: Blood, semen, vaginal secretions, CSF, synovial fluid, pleural fluid, pericardial fluid, amniotic fluid, etc.

2. Wash hands:

  • a. Immediately after contact with body substances containing blood
  • b. Between patient care
  • c. Immediately after gloves are removed.

3. Wear masks and protective eyewear when appropriate.

4. Wear moisture-proof apron when appropriate.

5. Wear utility (household rubber) gloves appropriately

6. Dispose of equipment and secretions properly

7. Wear sterile gloves appropriately

8. Handle specimens of blood and listed body fluids appropriately

9. Handle soiled linens correctly:

a. Hold linen away from uniform

b. Do not shake or toss linen

c. Transport linen contaminated with blood or bloody fluids in leakage resistant proof bags.

Painting Light

HOW TO PAINT LIGHT

I teach students how to paint and draw light. I am also a lighting specialist. My fascination with light encompasses, not only the commercial, retailing aspect, but the artistic as well. Once drawing and painting skills are developed to the point where students can accurately put down what they see, creating light and shadow is studied and faithfully delineated subject matter emerges in a world of space and volume.

LEARNING TO SEE

Basically, the depiction of light and shadow is accomplished by using dark and light colors in painting and tonal gradations in drawing. For a beginning student this often requires some visual skills.. First, I tell the student it is necessary to convert what they see to a two-dimensional vision that they can translate to a two-dimensional surface like a canvas or a sketchbook page.

POWERFUL GRIDS

Seeing objects two-dimensionally can be done in several ways. The easiest (and most time-tested) is to construct a grid in front of the subject matter–that could be actual objects, a photo or a picture. This can be done most simply by holding a pencil vertically and horizontally against the viewed objects, comparing their shapes to the vertical and horizontal lines of the pencil.

Another time-tested method is to literally construct a grid on plate glass or Plexiglas and place that grid in front of the objects. Now the viewed objects are intersected by many squares (depending on how large or small the squares in the grid are.) Each quadrant (square) of the grid can then be painted or drawn independently and upon completing the entire grid, the composition of objects is finished to compose an accurate picture of the objects.

Light and shadow are more easily discerned and created with this grid method. How objects are illuminated can be defined on paper or canvas by observing and re-creating light and shadow at play in each quadrant. In accomplishing this by shading and highlighting, illumination and therefore, volume is created, the illusion of the three-dimensional space is created, reborn on a two-dimensional surface.

EARLY LINE AND COLOR

Accuracy, as well as light and shadow were not always the motivation behind depicting artful images. Before the Renaissance, art works in Europe depicted objects ( figures, landscapes, buildings) in a flat space. There was no light and shadow. Figures were delineated and colored in a style much like a coloring book. These images translated well to stained glass windows and mosaics. Their simplicity of line and color contributed to the strength of the iconography, often of religious significance.

EARTHLY LIGHT

With the discovery of perspective, space and volume became important to artists as well as the depiction of light and shadow. Symbolic icons and images described by line gave way to depictions of illuminated space. In perspective, objects recede and advance in a two-dimensional space that is totally visually believable. To augment the receding and advancing figures with directional light and shadow completed the believability, creating a world the eye could explore as a simulated, illuminated three-dimensional environment.

GOLD LEAF TO EARTHLY LIGHT

Spiritual light, the vehicle of infinity was often expressed with the use of gold leaf in Medieval altarpieces. The warm, glowing, reflective surface behind religious figures imbued the work with a rich and reassuring statement-the glory of heaven and God’s power. A more earthly light replaced gold leaf in the Renaissance. Spiritual figures were bathed in sunlight and swathed in shadow. The light that illuminated the humble shepherds was the same light that shone on Jesus and his followers.

REPEATING HISTORY

It is interesting to me that the journey a beginning drawing or painting student takes often replicates the historical transition from the Medieval use of line and color-in style to the Renaissance application of illuminated space and volume. And, with more advanced students, their journey often continues to repeat the contemporary return to line and color-in, the preference for depicting flat, shallow space and solid color.

I find this reassuring. The art world is wide open, brimming with many styles, images, materials and skills. For today’s artist, everything is available, to use towards a creative purpose. All of history as well as the latest technological/digital images are ready to be researched and developed.

Using Power Tools 101

The power tools of today are not the same as the ones that were carefully placed on the pegboard near your grandfather’s workbench- they are actually quite far from it. Modern technology has made amazing advances in the simplest of features, including automatic shut-off, enhanced guarding and more resilient materials just to name a few. But one trait has come to be worth its weight in gold within the power tool industry, and that’s the owner’s manual.

Today’s manuals not only have better graphics showing its users what each part of the device should look like (and what to do when it doesn’t), many individual manufacturers will have explicit directions and instructions for the safety and maintenance of each individual power tool. Of course, no instructions are completely fool proof, especially if the content of such manuals isn’t completely understood by the user. This is why many manufacturers have implemented training seminars and classes for both companies and individuals on the proper procedures for optimum performance and safety. Local home improvement stores often hold such classes and seminars on a regular basis.

However, a bit of common sense and know-how never hurt anyone, so there are a few safety guidelines which should be followed by all users of power tools. For example, wearing the proper clothing is essential, and you should never wear loose clothing that could easily get caught in a power tool. Safety gear is crucial- hard hat, safety goggles and gloves, along with the proper footwear. Using the right tool, whether it be size or something else, for the job at hand, including the right type of extension cord (indoor, outdoor, proper length) if applicable. The work area should be clean, uncluttered and well lit. Keep all electric tools away from water and flammables. Do not use power tools with frayed or damaged cords. Damaged parts anywhere in a power tool, including saw blades and drill bits, can cause damage to the tool itself or the individual performing the task. Unplug all electric power tools when finished with or before changing to another tool.

As far as the maintenance aspect of such power tools, common sense is again of the highest importance. For example, making sure that the proper guards are placed on saw blades when not in use is both a safety and maintenance issue. Saw blades need to be sharp to deliver the best performance possible, but can also be incredibly dangerous, so taking the proper preventive measures will yield the best results in all aspects, not just project outcome.

For more information on power tool basics, the U.S. government has many publications that can be of high value to consumers. The U.S. Consumer Product Safety Commission offers product recall information, and OSHA has a few such publishings regarding both general industry and personal use of power tools.