Why are cardiology researchers inventing bogus definitions of species-wide heart enlargement to test risky drugs? Diuretics, of course, would not be appropriate prior to congestive heart failure, because their purpose is to remove retained fluids from the lungs, a situation which does not exist until CHF occurs. In the past year, veterinary research publications have been focusing their medication advice upon MVD-affected dogs with enlarged hearts rather than those in CHF.
Terminology[ edit ] Alphabet shift ciphers are believed to have been used by Julius Caesar over 2, years ago. In other words, the letters in the alphabet are shifted three in one direction to encrypt and three in the other direction to decrypt.
The first use of the term cryptograph as opposed to cryptogram dates back to the 19th century - it originated in The Gold-Buga novel by Edgar Allan Poe.
A cipher or cypher is a pair of algorithms that create the encryption and the reversing decryption. The detailed operation of a cipher is controlled both by the algorithm and in each instance by a " key ".
The key is a secret ideally known only to the communicantsusually a short string of characters, which is needed to decrypt the ciphertext. Formally, a " cryptosystem " is the ordered list of elements Examples of abstract in science investigatory project finite possible plaintexts, finite possible cyphertexts, finite possible keys, and the encryption and decryption algorithms which correspond to each key.
Keys are important both formally and in actual practice, as ciphers without variable keys can be trivially broken with only the knowledge of the cipher used and are therefore useless or even counter-productive for most purposes.
Historically, ciphers were often used directly for encryption or decryption without additional procedures such as authentication or integrity checks.
There are two kinds of cryptosystems: In symmetric systems the same key the secret key is used to encrypt and decrypt a message. Data manipulation in symmetric systems is faster than asymmetric systems as they generally use shorter key lengths. Asymmetric systems use a public key to encrypt a message and a private key to decrypt it.
Use of asymmetric systems enhances the security of communication. However, in cryptography, code has a more specific meaning. It means the replacement of a unit of plaintext i.
Cryptanalysis is the term used for the study of methods for obtaining the meaning of encrypted information without access to the key normally required to do so; i. Some use the terms cryptography and cryptology interchangeably in English, while others including US military practice generally use cryptography to refer specifically to the use and practice of cryptographic techniques and cryptology to refer to the combined study of cryptography and cryptanalysis.
History of cryptography and cryptanalysis[ edit ] Main article: History of cryptography Before the modern era, cryptography focused on message confidentiality i. Encryption attempted to ensure secrecy in communicationssuch as those of spiesmilitary leaders, and diplomats.
Reconstructed ancient Greek scytalean early cipher device The main classical cipher types are transposition cipherswhich rearrange the order of letters in a message e.
Simple versions of either have never offered much confidentiality from enterprising opponents. An early substitution cipher was the Caesar cipherin which each letter in the plaintext was replaced by a letter some fixed number of positions further down the alphabet. Suetonius reports that Julius Caesar used it with a shift of three to communicate with his generals.
Atbash is an example of an early Hebrew cipher. The earliest known use of cryptography is some carved ciphertext on stone in Egypt ca BCEbut this may have been done for the amusement of literate observers rather than as a way of concealing information.
The Greeks of Classical times are said to have known of ciphers e. In the Kautiliyam, the cipher letter substitutions are based on phonetic relations, such as vowels becoming consonants. In the Mulavediya, the cipher alphabet consists of pairing letters and using the reciprocal ones.
After the discovery of frequency analysisperhaps by the Arab mathematician and polymath Al-Kindi also known as Alkindus in the 9th century,  nearly all such ciphers could be broken by an informed attacker. Such classical ciphers still enjoy popularity today, though mostly as puzzles see cryptogram.
For those ciphers, language letter group or n-gram frequencies may provide an attack. Essentially all ciphers remained vulnerable to cryptanalysis using the frequency analysis technique until the development of the polyalphabetic cipher, most clearly by Leon Battista Alberti around the yearthough there is some indication that it was already known to Al-Kindi.
He also invented what was probably the first automatic cipher devicea wheel which implemented a partial realization of his invention. Breaking a message without using frequency analysis essentially required knowledge of the cipher used and perhaps of the key involved, thus making espionage, bribery, burglary, defection, etc.
Security of the key used should alone be sufficient for a good cipher to maintain confidentiality under an attack.This publication discusses common business expenses and explains what is and is not deductible.
The general rules for deducting business expenses are discussed in the opening chapter. The chapters that follow cover specific expenses and list other publications and forms you may need. Note. Section. Report of the Presidential Review Commission on the Reform and Transformation of the Public Service in South Africa.
An abstract is an abbreviated version of your science fair project final report. For most science fairs it is limited to a maximum of words (check the rules for your competition).
The science fair project abstract appears at the beginning of the report as well as on your display board. A paper by Jackie Calmes, Joan Shorenstein Fellow (Spring ) and national correspondent for The New York Times, examines the increasing influence of conservative media on the Republican Party’s agenda..
Calmes traces the history of conservative media, from its founding after World War II to the present-day . Guide to writing an abstract for a science fair project.
Includes a list of key elements for the abstract and examples. Please enter a search term in the text box.
A project report plays a significant role in the development of a given project. You must know how to create one that is sure to be effective.