Computer Studies Made Simple : Computer Network Models

Computer Network Models:

There are two main types of Computer Network Models:

1.Client Server Model

2.Peer to peer Model

1.Client Server Model:

This model consists of two types of computers The Server and The client/clients.

The Server controls whole of the network .

It stores the data and files that are shared among different computers/clients in the network.

This is the main computer in the network.

The other computers that are connected in the network are termed as client computers and  they request the server computer for data and files etc.

Its main advantages are as server is the main computer  and most powerful that provides  data to the connected computers/clients,less powerful computers can be used as clients.It also reduces the volume of data traffic on the network.

Its disadvantages include Its high costs and the entire network stops when the server computer crashes down.

Dermatology Made Simple : Changes in Nails in Systemic Disease

Changes in Nails in Systemic Disease

The nails may undergo many changes in various systemic diseases.

These changes vary according to the type of the disease and they also constitute important clinical signs and help in diagnosis of the nature of diseases.

Some of the common changes that occur in nails in systemic diseases are discussed below:

Clubbing:

This refers to loss of the normal angle between the base of nail and nail bed.

Also there would be an increase in the longitudinal and transverse curvature of the nails.

It occurs due to long standing swelling of periungal tissues of the nails secondary to hyperdynamic circulation in that part.

It has assocaitions with a range of diseases affecting different systems of the body.

Some of these are as follows:

Respiratory System:

Lung fibrosis

Fibrosing Alveolitis

Lung carcinoma

Bronchiectasis

Lung abscess  

Idiopathic Pulmonary Fibrosis

Cardiovascular Diseases:

Infective Endocarditis

Cyanotic Heart Diseases

Gastro Intestinal Systems:

Heaptocellular Carcinoma

Cirrhosis of Liver

Inflammatory Bowel Diseases : Crohns”s Disease

Ulcerative Colitis

Autoimmune Chronic Hepatitis

Primary Biliary Cirrhosis

Primary Sclerosing Cholangitis

 Clubbing of Nails

Koilonychia:

Also called as Spoon shaped deformity of the nails.

This is usually seen in adults in iron deficiency Anemia.

In children it occurs as normal variant.

 Koilonychai of Nails

Computer Studies Made Simple : Components of a computer Network

Components of a computer Network

1.Node:

Any computer which constitutes and exists in a computer network is termed as a Node.

It can also be called as a Terminal Computer and can be used to send or receive data between different users in a computer network.

2.Server Computer

This is the main computer in a Network .

It can control all other Terminal computers or Nodes in a network.

Computer Studies Made Simple : Collaborative Computing

Collaborative Computing

This term refers to sharing of information by a group of individuals who are working in collaboration with each other on a specific task.

The individuals in the group may be living in different parts of the world.

This use of computer is very efficient as it allows the individuals to share information of different types by computers using satellite signals and fibre-optics.

The information may include different files such as videos,pictures and sounds etc.

This form of computing has enabled different professionals from different parts of the world to work together and help in development of high quality projects.

Its is also called as Work Group Computing

Dermatology Made Simple : Fungal Infections of the Nails

Fungal Infections of the Nails

Onychomycosis:

This usually affects toenails.

The distal part of the nail is affected first.

This is followed by spreading of the disease to proximal parts of the nails.

The affected nail becomes brittle and thickened and colred yellow.

Management:

Topical treatment:

This is used for distal nail disease of mild type.

This includes : amorolfine and ciclopirox olamine 8 % solutions

Sodium pyrithione and imidazoles.

Systemic Therapy:

This includes Terbinafine 250 mg daily for 142 days. 

Computer Studies Made Simple : Computer Networks

Computer Networks

A computer network is a set of two or more than 2 computers that are connected with each other for 

purposes of sharing information and other applications.

The Computer network is also called as Information Netwrok

Components of a Computer Network:

These are as follows:

1.Computing

2.Telecommunications.

The computers are connected to each other via cable which may be fibreoptic,satellite data transmission or 

modem and phone lines.

Telecommunication refers to transfer of information over distances using optical signals or radio waves.

Dermatology Made Simple : Fungal infections of the Trunk

Fungal infections of the Trunk

These are usually caused by one of the below organisms:

Tinea Corporis

Candidia

Malassezia furfur

Tinea Corporis:

This is causes by a fungus Dermatophyte.

These usually live on the normal skin and cause rash when the environment is suitable for them or person is immunocompromised.

It can spread from person to person as direct contact.

Predisposing factors:

Individuals with immunosuppression

Individuals living in crowded and humid areas.

Lesions:

These are red colored erythematous with well defined scaly edge.

They affect the trunk,thighs and abdomen.

Management:

This is usually by Terbinafine cream 1 %.

Other options include :

Miconazole

Ketoconazole

Clotrimazole

These medications will have to be used for 2 – 4 weeks.

Systemic Therapy is in the form of Itraconazole 100 mg/day for 2 weeks

Differential Diagnosis

Differential Diagnosis for Tinea corporis includes: Erythrasma which is casued by Corynebacterium minutissimum and is treated by Tetracyclines.

Pityriasis Versicolor:

This is caused by Malasezia furfur

It affects upper back,arms and chest.

It causes well defined macules that vary in color from pale to dark brown.

They are covered with scales.

These lesions become more apparent when exposure to sun light takes place.

Treatment

Topical Selenium Sulphide and topical ketoconazole 2 % cream applied once daily for 2 weeks  that cures 

between 70 – 80 % of cases.

Differential Diagnosis for Pityriasis Versicolor includes:

Seborrhoeic dermatitis

Pityrisasis Rosea and

Vitiligo

Computer Studies Made Simple : Computer Storage Devices:

Computer Storage Devices

These are devices that are used to store data and programmes permanently.      

 

They are important because the main memory of a computer is not permanent and tends to lose data and programmes when the computer is powered off.

Also the main memory of a computer has limited capacity while these storage devices can store a large amount of data.

Following are common types of storage devices:

Magnetic Disk

Optical Disk

Magnetic Disc:

This includes the most widely used Hard Disk and the older discs such as floppy disc and magnetic tape.

Hard Drive / disc:

This is a type of magnetic disc.

It consists of several circular discs called platters which are used to store data.

A platter in a hard disc is coated with a magnetic material.

The hard disk in most personal computers is fixed inside the system unit.

It is a faster means of data storage and can store a large amount of data upto 500 Giga Bytes – 1 Tera 

Bytes.

It is also safer than most other means of data storage.