Issues about Scabies Rash

Scabies rash can be identified only if it is accompanied by other symptoms of scabies. If you have a severe, persistent rash that doesn’t seem to ease up it might be caused by infestation with scabies mites. Scabies rash is characterized through itching and soreness and it tends to intensify at night. Scabies rash may also become very irritated after taking a hot shower or bath. If the skin appears to be blistery and scratched and the presence of small burrows is revealed on the surface of the skin, it is a possible sign of scabies rash and appropriate dermatological treatment is required.

An overwhelming number of 300 million people worldwide are diagnosed with scabies each year. Scabies can be very easily acquired by simply touching a contaminated person. Although scabies is very contagious, scabies rash can’t be transmitted from a person to another. Scabies rash usually occurs when the body develops allergic reactions to scabies mites and their feces. The only contagious aspect of scabies involves the mite infestation. If the mites responsible for causing scabies are transmitted to a person, they will quickly infest the skin and the symptoms of scabies will occur within a few days. Scabies mites can be acquired through direct contact with an infested person or by touching or wearing contaminated clothes or personal items. Scabies mites can live without their human hosts for about 3 days and therefore they can easily contaminate bed sheets, clothes, towels, etc.

The main cause of scabies in people is contamination with a particular type of mite, called Sarcoptes scabiei var. hominis. This microscopic mite lives only on the bodies of human hosts and an infected person can spread it to hundreds of other persons.

It is important to note that scabies rash, just like other scabies symptoms, doesn’t occur due to improper hygiene. Although in the past, when the true nature of scabies wasn’t completely understood, people considered scabies rash to be the consequence of poor hygiene, today the cause of scabies rash is clear to most people. It is true that scabies occurs mostly to people from the lower classes of society, but this has nothing to do with hygiene. The factors that facilitate the   transmission  of scabies are overcrowding and situations that involve a lot of physical contact (factory workers). Hygiene can neither facilitate the occurrence of scabies, nor prevent it.

The most common symptoms of scabies are inflammation, discomfort, pain, swelling of the skin, pustules, burrows, nodules. However, the most intense of all seems to be the scabies rash. This symptom of scabies occurs as a result of allergic reactions to the mites’ feces, secretions, eggs and larvae.

Scabies rash is among the first symptoms that occur and it is usually the last one to disappear. Even if the condition is appropriately treated with topical medications, scabies rash may persist for another few weeks! This is due to the fact that even after they die, the mites remain under the skin and continue to produce allergies that cause scabies rash. The mites’ secretions contain substances that are toxic to the human body. However, there are ways of easing the itch, soreness and pain characteristic to scabies rash. Dermatologists usually prescribe hydrocortisone and antihistamine along with the treatment for scabies. These topical medications are usually in the form of creams, gels and ointments and they ameliorate scabies rash. However, if the scabies rash persists and even intensifies after a few weeks, it is a sign that the mite infestation hasn’t been eradicated and the treatment needs to be repeated.

Using Serialization

A common problem in programming is moving the program data to another spot, such as a file on disk or another computer. For example, suppose a video game needs to store a saved file on the hard drive. Normally, the developer would have to write a method that takes all the game information and puts it into a format that can be placed on disk. Another method needs to be written to reverse this. The concept of serialization, used in some programming languages, bypasses this.

If a language has serialization libraries, this means that these functions are built in. You can input an object and have built-in language libraries convert the object to data. And of course, you can do the reverse. Instead of having to write code and create your own format for storing program information, you can just have the language do it. This has a wide variety of uses besides the video game save file mentioned in the intro. Suppose you want any program to store user-inputted data. You can simply put that data into a serializable object, that write it to disk. When the program starts up again, use the deserialization methods.

This can also be used for network communications. Consider the problem of writing client and server programs that can communicate with each other. Instead of having to process data, you can just serialize the object and transmit its data over the network. As long as the client and server know what class is being used, this works.

However, not all programming languages can be serialized. Generally, this is only a feature of higher-level languages. .NET has it with the Serializable attribute for a class. For Java, the java.io.Serializable interface is used. Classes that implement this interface can be serialized. Even low-level languages such as C++ have the ability, albeit not in the standard library. The popular Boost C++ library has functions that provide the serialization ability.

However, there are also problems caused by serialization. Many languages do not have backwards compatibility. So if you write a new version of the program and try to use it with existing serialized data, it can fail. Fortunately, some languages do have backwards compatibility features that avoid this drawback.

Serialization is a useful tool that all programmers should know about. It provides an easy way to store program data permanently and transmit it between multiple computers. For languages where serialization libraries are built-in, this is generally very easy.

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.

The Best Investment Funds for 2014 and Beyond?

Here we go one step beyond the basics and suggest that the best investment funds for 2014 and beyond could be funds that invest money in alternative investments. You can debate whether diversified stock funds or bond funds will be the best funds to invest money in, but your best investment could be funds that invest money in alternative investments like gold, oil, and maybe even real estate stocks.

Informed investors know that you should invest money in more than one area in order to have a diversified portfolio. Most investors think that the best investment strategy is to own the best funds, and that your only choices are diversified stock funds and bond funds. Few have a handle on the arena called “alternative investments”. Where do you think the smart investors will invest money when neither stocks (in general) nor bonds look attractive and safe investments are paying record low interest rates?

The top dogs look around for opportunities that are “outside of the box” in search of their best investment alternatives. Welcome to the world of alternative investments. As an average investor trying to find the best funds you might want to broaden your horizons as well. If our economy continues to be lackluster and interest rates rise in 2014 and beyond both diversified stock funds and bond funds could take a hit. So, where can you invest money for higher returns if things turn sour in 2014 and/or 2015?

Gold is not cheap anymore but it is well below its highs as I write this. Gold funds invest money in stocks in the gold and silver mining industry, and they took a major hit in 2013. Historically, gold has been one of the best investment alternatives in times of high uncertainty and crisis. Gold funds might be one of the best funds if things get ugly in 2014 and beyond. They may or may not be your best investment, but adding them to your portfolio at this time to add more diversification could be a good idea just in case.

Another alternative investment that’s a candidate for best investment ideas: oil and other natural resources. Your best funds to invest money in here and keep things simple are called natural resources funds. They too have proven to be good performers when the stock market in general is having a rough time. You might think that gasoline prices at the pump (and oil prices) are high now, but think back a few years. Prices can always go higher, even in a bad economy.

And then there’s real estate as an alternative investment. This industry has recovered from the financial crisis lows, in no small part due to low interest rates. What will happen if rates climb as the economy sputters? Investors usually invest money in real estate with borrowed money. The truth of the matter is that interest rates are still low by historical standards. Real estate funds can be one of your best investment alternatives as investors rush in to buy before rates climb further. The best funds here invest money in real estate investment trusts and other companies in the real estate sector, like home builders. Caution: when rates rise significantly the real estate industry can sputter.

Why do I suggest that the best funds in 2014 and beyond could be those that invest money in specialized sectors like gold, natural resources and perhaps real estate? Historically, in bad times for the economy and stock market in general these industries can attract money as investors search for the best investment alternatives to invest money in. Both stocks (in general) and bonds are selling near historical highs. Bonds have been on a thirty year roll, and stocks have climbed 150% in less than five years. Neither looks cheap by any standard.

In your search for the best investment alternatives to make your money grow, sometimes you need to look outside of the box. You need to invest money so that some of it is safe and available for future opportunities. And in times like 2014 and beyond it’s a good idea to further diversify into alternative investments. The simplest and best investment vehicle for the average investor is mutual funds. The best funds to add to your portfolio are those that can swim against the tide when it goes out.