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ASCII was incorporated into the Unicode character set as the first 128 symbols, so the 7-bit ASCII characters have the same numeric codes in both sets. This allows UTF-8 to be backward compatible with 7-bit ASCII, as a UTF-8 file containing only ASCII characters is identical to an ASCII file containing the same sequence of characters. Even more importantly, forward compatibility is ensured as software that recognizes only 7-bit ASCII characters as special and does not alter bytes with the highest bit set (as is often done to support 8-bit ASCII extensions such as ISO-8859-1) will preserve UTF-8 data unchanged. |
When a Teletype 33 ASR equipped with the automatic paper tape reader received a Control-S (XOFF, an abbreviation for transmit off), it caused the tape reader to stop; receiving Control-Q (XON, "transmit on") caused the tape reader to resume. This technique became adopted by several early computer operating systems as a "handshaking" signal warning a sender to stop transmission because of impending overflow; it persists to this day in many systems as a manual output control technique. On some systems Control-S retains its meaning but Control-Q is replaced by a second Control-S to resume output. The 33 ASR also could be configured to employ Control-R (DC2) and Control-T (DC4) to start and stop the tape punch; on some units equipped with this function, the corresponding control character lettering on the keycap above the letter was TAPE and TAPE respectively. |
DEC operating systems (OS/8, RT-11, RSX-11, RSTS, TOPS-10, etc.) used both characters to mark the end of a line so that the console device (originally Teletype machines) would work. By the time so-called "glass TTYs" (later called CRTs or terminals) came along, the convention was so well established that backward compatibility necessitated continuing the convention. When Gary Kildall cloned RT-11 to create CP/M he followed established DEC convention. Until the introduction of PC DOS in 1981, IBM had no hand in this because their 1970s operating systems used EBCDIC instead of ASCII and they were oriented toward punch-card input and line printer output on which the concept of carriage return was meaningless. IBM's PC DOS (also marketed as MS-DOS by Microsoft) inherited the convention by virtue of being a clone of CP/M, and Windows inherited it from MS-DOS. |
C trigraphs were created to solve this problem for ANSI C, although their late introduction and inconsistent implementation in compilers limited their use. Many programmers kept their computers on US-ASCII, so plain-text in Swedish, German etc. (for example, in e-mail or Usenet) contained "{, }" and similar variants in the middle of words, something those programmers got used to. For example, a Swedish programmer mailing another programmer asking if they should go for lunch, could get "N{ jag har sm|rg}sar." as the answer, which should be "Nä jag har smörgåsar." meaning "No I've got sandwiches." |
The X3.2 subcommittee designed ASCII based on the earlier teleprinter encoding systems. Like other character encodings, ASCII specifies a correspondence between digital bit patterns and character symbols (i.e. graphemes and control characters). This allows digital devices to communicate with each other and to process, store, and communicate character-oriented information such as written language. Before ASCII was developed, the encodings in use included 26 alphabetic characters, 10 numerical digits, and from 11 to 25 special graphic symbols. To include all these, and control characters compatible with the Comité Consultatif International Téléphonique et Télégraphique (CCITT) International Telegraph Alphabet No. 2 (ITA2) standard, Fieldata, and early EBCDIC, more than 64 codes were required for ASCII. |
ASCII itself was first used commercially during 1963 as a seven-bit teleprinter code for American Telephone & Telegraph's TWX (TeletypeWriter eXchange) network. TWX originally used the earlier five-bit ITA2, which was also used by the competing Telex teleprinter system. Bob Bemer introduced features such as the escape sequence. His British colleague Hugh McGregor Ross helped to popularize this work – according to Bemer, "so much so that the code that was to become ASCII was first called the Bemer-Ross Code in Europe". Because of his extensive work on ASCII, Bemer has been called "the father of ASCII." |
For example, character 10 represents the "line feed" function (which causes a printer to advance its paper), and character 8 represents "backspace". RFC 2822 refers to control characters that do not include carriage return, line feed or white space as non-whitespace control characters. Except for the control characters that prescribe elementary line-oriented formatting, ASCII does not define any mechanism for describing the structure or appearance of text within a document. Other schemes, such as markup languages, address page and document layout and formatting. |
Some software assigned special meanings to ASCII characters sent to the software from the terminal. Operating systems from Digital Equipment Corporation, for example, interpreted DEL as an input character as meaning "remove previously-typed input character", and this interpretation also became common in Unix systems. Most other systems used BS for that meaning and used DEL to mean "remove the character at the cursor".[citation needed] That latter interpretation is the most common now.[citation needed] |
Computers attached to the ARPANET included machines running operating systems such as TOPS-10 and TENEX using CR-LF line endings, machines running operating systems such as Multics using LF line endings, and machines running operating systems such as OS/360 that represented lines as a character count followed by the characters of the line and that used EBCDIC rather than ASCII. The Telnet protocol defined an ASCII "Network Virtual Terminal" (NVT), so that connections between hosts with different line-ending conventions and character sets could be supported by transmitting a standard text format over the network. Telnet used ASCII along with CR-LF line endings, and software using other conventions would translate between the local conventions and the NVT. The File Transfer Protocol adopted the Telnet protocol, including use of the Network Virtual Terminal, for use when transmitting commands and transferring data in the default ASCII mode. This adds complexity to implementations of those protocols, and to other network protocols, such as those used for E-mail and the World Wide Web, on systems not using the NVT's CR-LF line-ending convention. |
From early in its development, ASCII was intended to be just one of several national variants of an international character code standard, ultimately published as ISO/IEC 646 (1972), which would share most characters in common but assign other locally useful characters to several code points reserved for "national use." However, the four years that elapsed between the publication of ASCII-1963 and ISO's first acceptance of an international recommendation during 1967 caused ASCII's choices for the national use characters to seem to be de facto standards for the world, causing confusion and incompatibility once other countries did begin to make their own assignments to these code points. |
Most early home computer systems developed their own 8-bit character sets containing line-drawing and game glyphs, and often filled in some or all of the control characters from 0–31 with more graphics. Kaypro CP/M computers used the "upper" 128 characters for the Greek alphabet. The IBM PC defined code page 437, which replaced the control-characters with graphic symbols such as smiley faces, and mapped additional graphic characters to the upper 128 positions. Operating systems such as DOS supported these code pages, and manufacturers of IBM PCs supported them in hardware. Digital Equipment Corporation developed the Multinational Character Set (DEC-MCS) for use in the popular VT220 terminal as one of the first extensions designed more for international languages than for block graphics. The Macintosh defined Mac OS Roman and Postscript also defined a set, both of these contained both international letters and typographic punctuation marks instead of graphics, more like modern character sets. |
ASCII (i/ˈæski/ ASS-kee), abbreviated from American Standard Code for Information Interchange, is a character-encoding scheme (the IANA prefers the name US-ASCII). ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many additional characters. ASCII was the most common character encoding on the World Wide Web until December 2007, when it was surpassed by UTF-8, which is fully backward compatibe to ASCII. |
The committee debated the possibility of a shift function (like in ITA2), which would allow more than 64 codes to be represented by a six-bit code. In a shifted code, some character codes determine choices between options for the following character codes. It allows compact encoding, but is less reliable for data transmission as an error in transmitting the shift code typically makes a long part of the transmission unreadable. The standards committee decided against shifting, and so ASCII required at least a seven-bit code.:215, 236 § 4 |
Many more of the control codes have been given meanings quite different from their original ones. The "escape" character (ESC, code 27), for example, was intended originally to allow sending other control characters as literals instead of invoking their meaning. This is the same meaning of "escape" encountered in URL encodings, C language strings, and other systems where certain characters have a reserved meaning. Over time this meaning has been co-opted and has eventually been changed. In modern use, an ESC sent to the terminal usually indicates the start of a command sequence, usually in the form of a so-called "ANSI escape code" (or, more properly, a "Control Sequence Introducer") beginning with ESC followed by a "[" (left-bracket) character. An ESC sent from the terminal is most often used as an out-of-band character used to terminate an operation, as in the TECO and vi text editors. In graphical user interface (GUI) and windowing systems, ESC generally causes an application to abort its current operation or to exit (terminate) altogether. |
Older operating systems such as TOPS-10, along with CP/M, tracked file length only in units of disk blocks and used Control-Z (SUB) to mark the end of the actual text in the file. For this reason, EOF, or end-of-file, was used colloquially and conventionally as a three-letter acronym for Control-Z instead of SUBstitute. The end-of-text code (ETX), also known as Control-C, was inappropriate for a variety of reasons, while using Z as the control code to end a file is analogous to it ending the alphabet and serves as a very convenient mnemonic aid. A historically common and still prevalent convention uses the ETX code convention to interrupt and halt a program via an input data stream, usually from a keyboard. |
ASCII developed from telegraphic codes. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6, 1960, with the first meeting of the American Standards Association's (ASA) X3.2 subcommittee. The first edition of the standard was published during 1963, underwent a major revision during 1967, and experienced its most recent update during 1986. Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters. |
The committee considered an eight-bit code, since eight bits (octets) would allow two four-bit patterns to efficiently encode two digits with binary-coded decimal. However, it would require all data transmission to send eight bits when seven could suffice. The committee voted to use a seven-bit code to minimize costs associated with data transmission. Since perforated tape at the time could record eight bits in one position, it also allowed for a parity bit for error checking if desired.:217, 236 § 5 Eight-bit machines (with octets as the native data type) that did not use parity checking typically set the eighth bit to 0. |
With the other special characters and control codes filled in, ASCII was published as ASA X3.4-1963, leaving 28 code positions without any assigned meaning, reserved for future standardization, and one unassigned control code.:66, 245 There was some debate at the time whether there should be more control characters rather than the lowercase alphabet.:435 The indecision did not last long: during May 1963 the CCITT Working Party on the New Telegraph Alphabet proposed to assign lowercase characters to columns 6 and 7, and International Organization for Standardization TC 97 SC 2 voted during October to incorporate the change into its draft standard. The X3.2.4 task group voted its approval for the change to ASCII at its May 1963 meeting. Locating the lowercase letters in columns 6 and 7 caused the characters to differ in bit pattern from the upper case by a single bit, which simplified case-insensitive character matching and the construction of keyboards and printers. |
Other international standards bodies have ratified character encodings such as ISO/IEC 646 that are identical or nearly identical to ASCII, with extensions for characters outside the English alphabet and symbols used outside the United States, such as the symbol for the United Kingdom's pound sterling (£). Almost every country needed an adapted version of ASCII, since ASCII suited the needs of only the USA and a few other countries. For example, Canada had its own version that supported French characters. Other adapted encodings include ISCII (India), VISCII (Vietnam), and YUSCII (Yugoslavia). Although these encodings are sometimes referred to as ASCII, true ASCII is defined strictly only by the ANSI standard. |
Probably the most influential single device on the interpretation of these characters was the Teletype Model 33 ASR, which was a printing terminal with an available paper tape reader/punch option. Paper tape was a very popular medium for long-term program storage until the 1980s, less costly and in some ways less fragile than magnetic tape. In particular, the Teletype Model 33 machine assignments for codes 17 (Control-Q, DC1, also known as XON), 19 (Control-S, DC3, also known as XOFF), and 127 (Delete) became de facto standards. The Model 33 was also notable for taking the description of Control-G (BEL, meaning audibly alert the operator) literally as the unit contained an actual bell which it rang when it received a BEL character. Because the keytop for the O key also showed a left-arrow symbol (from ASCII-1963, which had this character instead of underscore), a noncompliant use of code 15 (Control-O, Shift In) interpreted as "delete previous character" was also adopted by many early timesharing systems but eventually became neglected. |
The inherent ambiguity of many control characters, combined with their historical usage, created problems when transferring "plain text" files between systems. The best example of this is the newline problem on various operating systems. Teletype machines required that a line of text be terminated with both "Carriage Return" (which moves the printhead to the beginning of the line) and "Line Feed" (which advances the paper one line without moving the printhead). The name "Carriage Return" comes from the fact that on a manual typewriter the carriage holding the paper moved while the position where the typebars struck the ribbon remained stationary. The entire carriage had to be pushed (returned) to the right in order to position the left margin of the paper for the next line. |
Many of the non-alphanumeric characters were positioned to correspond to their shifted position on typewriters; an important subtlety is that these were based on mechanical typewriters, not electric typewriters. Mechanical typewriters followed the standard set by the Remington No. 2 (1878), the first typewriter with a shift key, and the shifted values of 23456789- were "#$%_&'() – early typewriters omitted 0 and 1, using O (capital letter o) and l (lowercase letter L) instead, but 1! and 0) pairs became standard once 0 and 1 became common. Thus, in ASCII !"#$% were placed in second column, rows 1–5, corresponding to the digits 1–5 in the adjacent column. The parentheses could not correspond to 9 and 0, however, because the place corresponding to 0 was taken by the space character. This was accommodated by removing _ (underscore) from 6 and shifting the remaining characters left, which corresponded to many European typewriters that placed the parentheses with 8 and 9. This discrepancy from typewriters led to bit-paired keyboards, notably the Teletype Model 33, which used the left-shifted layout corresponding to ASCII, not to traditional mechanical typewriters. Electric typewriters, notably the more recently introduced IBM Selectric (1961), used a somewhat different layout that has become standard on computers—following the IBM PC (1981), especially Model M (1984)—and thus shift values for symbols on modern keyboards do not correspond as closely to the ASCII table as earlier keyboards did. The /? pair also dates to the No. 2, and the ,< .> pairs were used on some keyboards (others, including the No. 2, did not shift , (comma) or . (full stop) so they could be used in uppercase without unshifting). However, ASCII split the ;: pair (dating to No. 2), and rearranged mathematical symbols (varied conventions, commonly -* =+) to :* ;+ -=. |
Code 127 is officially named "delete" but the Teletype label was "rubout". Since the original standard did not give detailed interpretation for most control codes, interpretations of this code varied. The original Teletype meaning, and the intent of the standard, was to make it an ignored character, the same as NUL (all zeroes). This was useful specifically for paper tape, because punching the all-ones bit pattern on top of an existing mark would obliterate it. Tapes designed to be "hand edited" could even be produced with spaces of extra NULs (blank tape) so that a block of characters could be "rubbed out" and then replacements put into the empty space. |
Unfortunately, requiring two characters to mark the end of a line introduces unnecessary complexity and questions as to how to interpret each character when encountered alone. To simplify matters plain text data streams, including files, on Multics used line feed (LF) alone as a line terminator. Unix and Unix-like systems, and Amiga systems, adopted this convention from Multics. The original Macintosh OS, Apple DOS, and ProDOS, on the other hand, used carriage return (CR) alone as a line terminator; however, since Apple replaced these operating systems with the Unix-based OS X operating system, they now use line feed (LF) as well. |
In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. Saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food; the saliva also contains mucus, which lubricates the food, and hydrogen carbonate, which provides the ideal conditions of pH (alkaline) for amylase to work. After undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. It will then travel down the esophagus and into the stomach by the action of peristalsis. Gastric juice in the stomach starts protein digestion. Gastric juice mainly contains hydrochloric acid and pepsin. As these two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the damaging effects of the chemicals. At the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. This allows the mass of food to further mix with the digestive enzymes. |
Other animals, such as rabbits and rodents, practise coprophagia behaviours - eating specialised faeces in order to re-digest food, especially in the case of roughage. Capybara, rabbits, hamsters and other related species do not have a complex digestive system as do, for example, ruminants. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft faecal pellets of partially digested food are excreted and generally consumed immediately. They also produce normal droppings, which are not eaten. |
Digestive systems take many forms. There is a fundamental distinction between internal and external digestion. External digestion developed earlier in evolutionary history, and most fungi still rely on it. In this process, enzymes are secreted into the environment surrounding the organism, where they break down an organic material, and some of the products diffuse back to the organism. Animals have a tube (gastrointestinal tract) in which internal digestion occurs, which is more efficient because more of the broken down products can be captured, and the internal chemical environment can be more efficiently controlled. |
The nitrogen fixing Rhizobia are an interesting case, wherein conjugative elements naturally engage in inter-kingdom conjugation. Such elements as the Agrobacterium Ti or Ri plasmids contain elements that can transfer to plant cells. Transferred genes enter the plant cell nucleus and effectively transform the plant cells into factories for the production of opines, which the bacteria use as carbon and energy sources. Infected plant cells form crown gall or root tumors. The Ti and Ri plasmids are thus endosymbionts of the bacteria, which are in turn endosymbionts (or parasites) of the infected plant. |
Teeth (singular tooth) are small whitish structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, milk and chew food. Teeth are not made of bone, but rather of tissues of varying density and hardness, such as enamel, dentine and cementum. Human teeth have a blood and nerve supply which enables proprioception. This is the ability of sensation when chewing, for example if we were to bite into something too hard for our teeth, such as a chipped plate mixed in food, our teeth send a message to our brain and we realise that it cannot be chewed, so we stop trying. |
The abomasum is the fourth and final stomach compartment in ruminants. It is a close equivalent of a monogastric stomach (e.g., those in humans or pigs), and digesta is processed here in much the same way. It serves primarily as a site for acid hydrolysis of microbial and dietary protein, preparing these protein sources for further digestion and absorption in the small intestine. Digesta is finally moved into the small intestine, where the digestion and absorption of nutrients occurs. Microbes produced in the reticulo-rumen are also digested in the small intestine. |
An earthworm's digestive system consists of a mouth, pharynx, esophagus, crop, gizzard, and intestine. The mouth is surrounded by strong lips, which act like a hand to grab pieces of dead grass, leaves, and weeds, with bits of soil to help chew. The lips break the food down into smaller pieces. In the pharynx, the food is lubricated by mucus secretions for easier passage. The esophagus adds calcium carbonate to neutralize the acids formed by food matter decay. Temporary storage occurs in the crop where food and calcium carbonate are mixed. The powerful muscles of the gizzard churn and mix the mass of food and dirt. When the churning is complete, the glands in the walls of the gizzard add enzymes to the thick paste, which helps chemically breakdown the organic matter. By peristalsis, the mixture is sent to the intestine where friendly bacteria continue chemical breakdown. This releases carbohydrates, protein, fat, and various vitamins and minerals for absorption into the body. |
Digestion of some fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids. Complete digestion of one molecule of fat (a triglyceride) results a mixture of fatty acids, mono- and di-glycerides, as well as some undigested triglycerides, but no free glycerol molecules. |
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. In chemical digestion, enzymes break down food into the small molecules the body can use. |
Different phases of digestion take place including: the cephalic phase , gastric phase, and intestinal phase. The cephalic phase occurs at the sight, thought and smell of food, which stimulate the cerebral cortex. Taste and smell stimuli are sent to the hypothalamus and medulla oblongata. After this it is routed through the vagus nerve and release of acetylcholine. Gastric secretion at this phase rises to 40% of maximum rate. Acidity in the stomach is not buffered by food at this point and thus acts to inhibit parietal (secretes acid) and G cell (secretes gastrin) activity via D cell secretion of somatostatin. The gastric phase takes 3 to 4 hours. It is stimulated by distension of the stomach, presence of food in stomach and decrease in pH. Distention activates long and myenteric reflexes. This activates the release of acetylcholine, which stimulates the release of more gastric juices. As protein enters the stomach, it binds to hydrogen ions, which raises the pH of the stomach. Inhibition of gastrin and gastric acid secretion is lifted. This triggers G cells to release gastrin, which in turn stimulates parietal cells to secrete gastric acid. Gastric acid is about 0.5% hydrochloric acid (HCl), which lowers the pH to the desired pH of 1-3. Acid release is also triggered by acetylcholine and histamine. The intestinal phase has two parts, the excitatory and the inhibitory. Partially digested food fills the duodenum. This triggers intestinal gastrin to be released. Enterogastric reflex inhibits vagal nuclei, activating sympathetic fibers causing the pyloric sphincter to tighten to prevent more food from entering, and inhibits local reflexes. |
In a channel transupport system, several proteins form a contiguous channel traversing the inner and outer membranes of the bacteria. It is a simple system, which consists of only three protein subunits: the ABC protein, membrane fusion protein (MFP), and outer membrane protein (OMP)[specify]. This secretion system transports various molecules, from ions, drugs, to proteins of various sizes (20 - 900 kDa). The molecules secreted vary in size from the small Escherichia coli peptide colicin V, (10 kDa) to the Pseudomonas fluorescens cell adhesion protein LapA of 900 kDa. |
In addition to the use of the multiprotein complexes listed above, Gram-negative bacteria possess another method for release of material: the formation of outer membrane vesicles. Portions of the outer membrane pinch off, forming spherical structures made of a lipid bilayer enclosing periplasmic materials. Vesicles from a number of bacterial species have been found to contain virulence factors, some have immunomodulatory effects, and some can directly adhere to and intoxicate host cells. While release of vesicles has been demonstrated as a general response to stress conditions, the process of loading cargo proteins seems to be selective. |
Underlying the process is muscle movement throughout the system through swallowing and peristalsis. Each step in digestion requires energy, and thus imposes an "overhead charge" on the energy made available from absorbed substances. Differences in that overhead cost are important influences on lifestyle, behavior, and even physical structures. Examples may be seen in humans, who differ considerably from other hominids (lack of hair, smaller jaws and musculature, different dentition, length of intestines, cooking, etc.). |
Digestion begins in the mouth with the secretion of saliva and its digestive enzymes. Food is formed into a bolus by the mechanical mastication and swallowed into the esophagus from where it enters the stomach through the action of peristalsis. Gastric juice contains hydrochloric acid and pepsin which would damage the walls of the stomach and mucus is secreted for protection. In the stomach further release of enzymes break down the food further and this is combined with the churning action of the stomach. The partially digested food enters the duodenum as a thick semi-liquid chyme. In the small intestine, the larger part of digestion takes place and this is helped by the secretions of bile, pancreatic juice and intestinal juice. The intestinal walls are lined with villi, and their epithelial cells is covered with numerous microvilli to improve the absorption of nutrients by increasing the surface area of the intestine. |
Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose. Glucose and galactose can be absorbed by the small intestine. Approximately 65 percent of the adult population produce only small amounts of lactase and are unable to eat unfermented milk-based foods. This is commonly known as lactose intolerance. Lactose intolerance varies widely by ethnic heritage; more than 90 percent of peoples of east Asian descent are lactose intolerant, in contrast to about 5 percent of people of northern European descent. |
After some time (typically 1–2 hours in humans, 4–6 hours in dogs, 3–4 hours in house cats),[citation needed] the resulting thick liquid is called chyme. When the pyloric sphincter valve opens, chyme enters the duodenum where it mixes with digestive enzymes from the pancreas and bile juice from the liver and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. 95% of absorption of nutrients occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH is slightly acidic about 5.6 ~ 6.9. Some vitamins, such as biotin and vitamin K (K2MK7) produced by bacteria in the colon are also absorbed into the blood in the colon. Waste material is eliminated from the rectum during defecation. |
In mammals, preparation for digestion begins with the cephalic phase in which saliva is produced in the mouth and digestive enzymes are produced in the stomach. Mechanical and chemical digestion begin in the mouth where food is chewed, and mixed with saliva to begin enzymatic processing of starches. The stomach continues to break food down mechanically and chemically through churning and mixing with both acids and enzymes. Absorption occurs in the stomach and gastrointestinal tract, and the process finishes with defecation. |
Protein digestion occurs in the stomach and duodenum in which 3 main enzymes, pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids. The digestive enzymes however are mostly secreted as their inactive precursors, the zymogens. For example, trypsin is secreted by pancreas in the form of trypsinogen, which is activated in the duodenum by enterokinase to form trypsin. Trypsin then cleaves proteins to smaller polypeptides. |
Hoover began using wiretapping in the 1920s during Prohibition to arrest bootleggers. In the 1927 case Olmstead v. United States, in which a bootlegger was caught through telephone tapping, the United States Supreme Court ruled that FBI wiretaps did not violate the Fourth Amendment as unlawful search and seizure, as long as the FBI did not break into a person's home to complete the tapping. After Prohibition's repeal, Congress passed the Communications Act of 1934, which outlawed non-consensual phone tapping, but allowed bugging. In the 1939 case Nardone v. United States, the court ruled that due to the 1934 law, evidence the FBI obtained by phone tapping was inadmissible in court. After the 1967 case Katz v. United States overturned the 1927 case that had allowed bugging, Congress passed the Omnibus Crime Control Act, allowing public authorities to tap telephones during investigations as long as they obtain a warrant beforehand. |
In March 1971, the residential office of an FBI agent in Media, Pennsylvania was burglarized by a group calling itself the Citizens' Commission to Investigate the FBI. Numerous files were taken and distributed to a range of newspapers, including The Harvard Crimson. The files detailed the FBI's extensive COINTELPRO program, which included investigations into lives of ordinary citizens—including a black student group at a Pennsylvania military college and the daughter of Congressman Henry Reuss of Wisconsin. The country was "jolted" by the revelations, which included assassinations of political activists, and the actions were denounced by members of Congress, including House Majority Leader Hale Boggs. The phones of some members of Congress, including Boggs, had allegedly been tapped. |
From the end of the 1980s to the early 1990s, the FBI reassigned more than 300 agents from foreign counter-intelligence duties to violent crime, and made violent crime the sixth national priority. With reduced cuts to other well-established departments, and because terrorism was no longer considered a threat after the end of the Cold War, the FBI assisted local and state police forces in tracking fugitives who had crossed state lines, which is a federal offense. The FBI Laboratory helped develop DNA testing, continuing its pioneering role in identification that began with its fingerprinting system in 1924. |
The 9/11 Commission's final report on July 22, 2004 stated that the FBI and Central Intelligence Agency (CIA) were both partially to blame for not pursuing intelligence reports that could have prevented the September 11, 2001 attacks. In its most damning assessment, the report concluded that the country had "not been well served" by either agency and listed numerous recommendations for changes within the FBI. While the FBI has acceded to most of the recommendations, including oversight by the new Director of National Intelligence, some former members of the 9/11 Commission publicly criticized the FBI in October 2005, claiming it was resisting any meaningful changes. |
The Criminal Justice Information Services (CJIS) Division, is located in Clarksburg, West Virginia. Organized beginning in 1991, the office opened in 1995 as the youngest agency division. The complex is the length of three football fields. It provides a main repository for information in various data systems. Under the roof of the CJIS are the programs for the National Crime Information Center (NCIC), Uniform Crime Reporting (UCR), Fingerprint Identification, Integrated Automated Fingerprint Identification System (IAFIS), NCIC 2000, and the National Incident-Based Reporting System (NIBRS). Many state and local agencies use these data systems as a source for their own investigations and contribute to the database using secure communications. FBI provides these tools of sophisticated identification and information services to local, state, federal, and international law enforcement agencies. |
The FBI director is responsible for the day-to-day operations at the FBI. Along with his deputies, the director makes sure cases and operations are handled correctly. The director also is in charge of making sure the leadership in any one of the FBI field offices is manned with qualified agents. Before the Intelligence Reform and Terrorism Prevention Act was passed in the wake of the September 11 attacks, the FBI director would directly brief the President of the United States on any issues that arise from within the FBI. Since then, the director now reports to the Director of National Intelligence (DNI), who in turn reports to the President. |
The Uniform Crime Reports (UCR) compile data from over 17,000 law enforcement agencies across the country. They provide detailed data regarding the volume of crimes to include arrest, clearance (or closing a case), and law enforcement officer information. The UCR focuses its data collection on violent crimes, hate crimes, and property crimes. Created in the 1920s, the UCR system has not proven to be as uniform as its name implies. The UCR data only reflect the most serious offense in the case of connected crimes and has a very restrictive definition of rape. Since about 93% of the data submitted to the FBI is in this format, the UCR stands out as the publication of choice as most states require law enforcement agencies to submit this data. |
FBI records show that 85% of COINTELPRO resources targeted groups and individuals that the FBI deemed "subversive", including communist and socialist organizations; organizations and individuals associated with the Civil Rights Movement, including Martin Luther King, Jr. and others associated with the Southern Christian Leadership Conference, the National Association for the Advancement of Colored People, and the Congress of Racial Equality and other civil rights organizations; black nationalist groups; the American Indian Movement; a broad range of organizations labeled "New Left", including Students for a Democratic Society and the Weathermen; almost all groups protesting the Vietnam War, as well as individual student demonstrators with no group affiliation; the National Lawyers Guild; organizations and individuals associated with the women's rights movement; nationalist groups such as those seeking independence for Puerto Rico, United Ireland, and Cuban exile movements including Orlando Bosch's Cuban Power and the Cuban Nationalist Movement. The remaining 15% of COINTELPRO resources were expended to marginalize and subvert white hate groups, including the Ku Klux Klan and the National States' Rights Party. |
Although many of FBI's functions are unique, its activities in support of national security are comparable to those of the British MI5 and the Russian FSB. Unlike the Central Intelligence Agency (CIA), which has no law enforcement authority and is focused on intelligence collection overseas, FBI is primarily a domestic agency, maintaining 56 field offices in major cities throughout the United States, and more than 400 resident agencies in lesser cities and areas across the nation. At an FBI field office, a senior-level FBI officer concurrently serves as the representative of the Director of National Intelligence. |
The bureau's first official task was visiting and making surveys of the houses of prostitution in preparation for enforcing the "White Slave Traffic Act," or Mann Act, passed on June 25, 1910. In 1932, it was renamed the United States Bureau of Investigation. The following year it was linked to the Bureau of Prohibition and rechristened the Division of Investigation (DOI) before finally becoming an independent service within the Department of Justice in 1935. In the same year, its name was officially changed from the Division of Investigation to the present-day Federal Bureau of Investigation, or FBI. |
During the 1950s and 1960s, FBI officials became increasingly concerned about the influence of civil rights leaders, whom they believed had communist ties or were unduly influenced by them. In 1956, for example, Hoover sent an open letter denouncing Dr. T.R.M. Howard, a civil rights leader, surgeon, and wealthy entrepreneur in Mississippi who had criticized FBI inaction in solving recent murders of George W. Lee, Emmett Till, and other blacks in the South. The FBI carried out controversial domestic surveillance in an operation it called the COINTELPRO, which was short for "COunter-INTELligence PROgram." It was to investigate and disrupt the activities of dissident political organizations within the United States, including both militant and non-violent organizations. Among its targets was the Southern Christian Leadership Conference, a leading civil rights organization with clergy leadership. |
Beginning in the 1940s and continuing into the 1970s, the bureau investigated cases of espionage against the United States and its allies. Eight Nazi agents who had planned sabotage operations against American targets were arrested, and six were executed (Ex parte Quirin) under their sentences. Also during this time, a joint US/UK code-breaking effort (the Venona project)—with which the FBI was heavily involved—broke Soviet diplomatic and intelligence communications codes, allowing the US and British governments to read Soviet communications. This effort confirmed the existence of Americans working in the United States for Soviet intelligence. Hoover was administering this project but failed to notify the Central Intelligence Agency (CIA) until 1952. Another notable case is the arrest of Soviet spy Rudolf Abel in 1957. The discovery of Soviet spies operating in the US allowed Hoover to pursue his longstanding obsession with the threat he perceived from the American Left, ranging from Communist Party of the United States of America (CPUSA) union organizers to American liberals. |
In 2003 a congressional committee called the FBI's organized crime informant program "one of the greatest failures in the history of federal law enforcement." The FBI allowed four innocent men to be convicted of the March 1965 gangland murder of Edward "Teddy" Deegan in order to protect Vincent Flemmi, an FBI informant. Three of the men were sentenced to death (which was later reduced to life in prison), and the fourth defendant was sentenced to life in prison. Two of the four men died in prison after serving almost 30 years, and two others were released after serving 32 and 36 years. In July 2007, U.S. District Judge Nancy Gertner in Boston found the bureau helped convict the four men using false witness account by mobster Joseph Barboza. The U.S. Government was ordered to pay $100 million in damages to the four defendants. |
Between 1993 and 1996, the FBI increased its counter-terrorism role in the wake of the first 1993 World Trade Center bombing in New York City, New York; the 1995 Oklahoma City bombing in Oklahoma City, Oklahoma; and the arrest of the Unabomber in 1996. Technological innovation and the skills of FBI Laboratory analysts helped ensure that the three cases were successfully prosecuted. Justice Department investigations into the FBI's roles in the Ruby Ridge and Waco incidents were found to be obstructed by agents within the Bureau. During the 1996 Summer Olympics in Atlanta, Georgia, the FBI was criticized for its investigation of the Centennial Olympic Park bombing. It has settled a dispute with Richard Jewell, who was a private security guard at the venue, along with some media organizations, in regard to the leaking of his name during the investigation. |
During the September 11, 2001 attacks on the World Trade Center, FBI agent Leonard W. Hatton Jr. was killed during the rescue effort while helping the rescue personnel evacuate the occupants of the South Tower and stayed when it collapsed. Within months after the attacks, FBI Director Robert Mueller, who had been sworn in a week before the attacks, called for a re-engineering of FBI structure and operations. He made countering every federal crime a top priority, including the prevention of terrorism, countering foreign intelligence operations, addressing cyber security threats, other high-tech crimes, protecting civil rights, combating public corruption, organized crime, white-collar crime, and major acts of violent crime. |
On July 8, 2007 The Washington Post published excerpts from UCLA Professor Amy Zegart's book Spying Blind: The CIA, the FBI, and the Origins of 9/11. The Post reported from Zegart's book that government documents show the CIA and FBI missed 23 potential chances to disrupt the terrorist attacks of September 11, 2001. The primary reasons for the failures included: agency cultures resistant to change and new ideas; inappropriate incentives for promotion; and a lack of cooperation between the FBI, CIA and the rest of the United States Intelligence Community. The book blamed the FBI's decentralized structure, which prevented effective communication and cooperation among different FBI offices. The book suggested that the FBI has not evolved into an effective counter-terrorism or counter-intelligence agency, due in large part to deeply ingrained agency cultural resistance to change. For example, FBI personnel practices continue to treat all staff other than special agents as support staff, classifying intelligence analysts alongside the FBI's auto mechanics and janitors. |
The USA PATRIOT Act increased the powers allotted to the FBI, especially in wiretapping and monitoring of Internet activity. One of the most controversial provisions of the act is the so-called sneak and peek provision, granting the FBI powers to search a house while the residents are away, and not requiring them to notify the residents for several weeks afterwards. Under the PATRIOT Act's provisions, the FBI also resumed inquiring into the library records of those who are suspected of terrorism (something it had supposedly not done since the 1970s). |
The FBI Laboratory, established with the formation of the BOI, did not appear in the J. Edgar Hoover Building until its completion in 1974. The lab serves as the primary lab for most DNA, biological, and physical work. Public tours of FBI headquarters ran through the FBI laboratory workspace before the move to the J. Edgar Hoover Building. The services the lab conducts include Chemistry, Combined DNA Index System (CODIS), Computer Analysis and Response, DNA Analysis, Evidence Response, Explosives, Firearms and Tool marks, Forensic Audio, Forensic Video, Image Analysis, Forensic Science Research, Forensic Science Training, Hazardous Materials Response, Investigative and Prospective Graphics, Latent Prints, Materials Analysis, Questioned Documents, Racketeering Records, Special Photographic Analysis, Structural Design, and Trace Evidence. The services of the FBI Laboratory are used by many state, local, and international agencies free of charge. The lab also maintains a second lab at the FBI Academy. |
In 2000, the FBI began the Trilogy project to upgrade its outdated information technology (IT) infrastructure. This project, originally scheduled to take three years and cost around $380 million, ended up going far over budget and behind schedule. Efforts to deploy modern computers and networking equipment were generally successful, but attempts to develop new investigation software, outsourced to Science Applications International Corporation (SAIC), were not. Virtual Case File, or VCF, as the software was known, was plagued by poorly defined goals, and repeated changes in management. In January 2005, more than two years after the software was originally planned for completion, the FBI officially abandoned the project. At least $100 million (and much more by some estimates) was spent on the project, which never became operational. The FBI has been forced to continue using its decade-old Automated Case Support system, which IT experts consider woefully inadequate. In March 2005, the FBI announced it was beginning a new, more ambitious software project, code-named Sentinel, which they expected to complete by 2009. |
An FBI special agent is issued a Glock Model 22 pistol or a Glock 23 in .40 S&W caliber. If they fail their first qualification, they are issued either a Glock 17 or Glock 19, to aid in their next qualification. In May 1997, the FBI officially adopted the Glock .40 S&W pistol for general agent use and first issued it to New Agent Class 98-1 in October 1997. At present, the Model 23 "FG&R" (finger groove and rail) is the issue sidearm. New agents are issued firearms, on which they must qualify, on successful completion of their training at the FBI Academy. The Glock 26 in 9×19mm Parabellum, and Glock Models 23 and 27 in .40 S&W caliber are authorized as secondary weapons. Special agents are authorized to purchase and qualify with the Glock Model 21 in .45 ACP. Special agents of the FBI HRT (Hostage Rescue Team), and regional SWAT teams are issued the Springfield Professional Model 1911A1 .45 ACP pistol (see FBI Special Weapons and Tactics Teams). |
The FBI is near-impenetrable, with applicants intensely scrutinized and assessed over an extended period. To apply to become an FBI agent, one must be between the ages of 23 and 37. Due to the decision in Robert P. Isabella v. Department of State and Office of Personnel Management, 2008 M.S.P.B. 146, preference-eligible veterans may apply after age 37. In 2009, the Office of Personnel Management issued implementation guidance on the Isabella decision. The applicant must also hold American citizenship, be of high moral character, have a clean record, and hold at least a four-year bachelor's degree. At least three years of professional work experience prior to application is also required. All FBI employees require a Top Secret (TS) security clearance, and in many instances, employees need a TS/SCI (Top Secret/Sensitive Compartmented Information) clearance. To obtain a security clearance, all potential FBI personnel must pass a series of Single Scope Background Investigations (SSBI), which are conducted by the Office of Personnel Management. Special Agents candidates also have to pass a Physical Fitness Test (PFT), which includes a 300-meter run, one-minute sit-ups, maximum push-ups, and a 1.5-mile (2.4 km) run. Personnel must pass a polygraph test with questions including possible drug use. Applicants who fail polygraphs may not gain employment with the FBI. |
The FBI has maintained files on numerous people, including celebrities such as Elvis Presley, Frank Sinatra, John Denver, John Lennon, Jane Fonda, Groucho Marx, Charlie Chaplin, the band MC5, Lou Costello, Sonny Bono, Bob Dylan, Michael Jackson, and Mickey Mantle. The files were collected for various reasons. Some of the subjects were investigated for alleged ties to the Communist party (Charlie Chaplin and Groucho Marx), or in connection with antiwar activities during the Vietnam War (John Denver, John Lennon, and Jane Fonda). Numerous celebrity files concern threats or extortion attempts against them (Sonny Bono, John Denver, John Lennon, Elvis Presley, Michael Jackson, Mickey Mantle, Groucho Marx, and Frank Sinatra). |
In December 1994, after being tipped off by his former FBI handler about a pending indictment under the Racketeer Influenced and Corrupt Organizations Act, Bulger fled Boston and went into hiding. For 16 years, he remained at large. For 12 of those years, Bulger was prominently listed on the FBI Ten Most Wanted Fugitives list. Beginning in 1997, the New England media exposed criminal actions by federal, state, and local law enforcement officials tied to Bulger. The revelation caused great embarrassment to the FBI. In 2002, Special Agent John J Connolly was convicted of federal racketeering charges for helping Bulger avoid arrest. In 2008, Special Agent Connolly completed his term on the federal charges and was transferred to Florida where he was convicted of helping plan the murder of John B Callahan, a Bulger rival. In 2014, that conviction was overturned on a technicality. Connolly was the agent leading the investigation of Bulger. |
In August 2007 Virgil Griffith, a Caltech computation and neural-systems graduate student, created a searchable database that linked changes made by anonymous Wikipedia editors to companies and organizations from which the changes were made. The database cross-referenced logs of Wikipedia edits with publicly available records pertaining to the internet IP addresses edits were made from. Griffith was motivated by the edits from the United States Congress, and wanted to see if others were similarly promoting themselves. The tool was designed to detect conflict of interest edits. Among his findings were that FBI computers were used to edit the FBI article in Wikipedia. Although the edits correlated with known FBI IP addresses, there was no proof that the changes actually came from a member or employee of the FBI, only that someone who had access to their network had edited the FBI article in Wikipedia. Wikipedia spokespersons received Griffith's "WikiScanner" positively, noting that it helped prevent conflicts of interest from influencing articles as well as increasing transparency and mitigating attempts to remove or distort relevant facts. |
On 20 February 2001, the bureau announced that a special agent, Robert Hanssen (born 1944) had been arrested for spying for the Soviet Union and then Russia from 1979 to 2001. He is serving 15 consecutive life sentences without the possibility of parole at ADX Florence, a federal supermax prison near Florence, Colorado. Hanssen was arrested on February 18, 2001 at Foxstone Park near his home in Vienna, Virginia, and was charged with selling US secrets to the USSR and subsequently Russia for more than US$1.4 million in cash and diamonds over a 22-year period. On July 6, 2001, he pleaded guilty to 15 counts of espionage in the United States District Court for the Eastern District of Virginia. His spying activities have been described by the US Department of Justice's Commission for the Review of FBI Security Programs as "possibly the worst intelligence disaster in U.S. history". |
The Federal Bureau of Investigation (FBI) is the domestic intelligence and security service of the United States, which simultaneously serves as the nation's prime federal law enforcement organization. Operating under the jurisdiction of the U.S. Department of Justice, FBI is concurrently a member of the U.S. Intelligence Community and reports to both the Attorney General and the Director of National Intelligence. A leading U.S. counterterrorism, counterintelligence, and criminal investigative organization, FBI has jurisdiction over violations of more than 200 categories of federal crimes. |
J. Edgar Hoover served as Director from 1924 to 1972, a combined 48 years with the BOI, DOI, and FBI. He was chiefly responsible for creating the Scientific Crime Detection Laboratory, or the FBI Laboratory, which officially opened in 1932, as part of his work to professionalize investigations by the government. Hoover was substantially involved in most major cases and projects that the FBI handled during his tenure. After Hoover's death, Congress passed legislation that limited the tenure of future FBI Directors to ten years. |
Despite its domestic focus, the FBI also maintains a significant international footprint, operating 60 Legal Attache (LEGAT) offices and 15 sub-offices in U.S. embassies and consulates across the globe. These overseas offices exist primarily for the purpose of coordination with foreign security services and do not usually conduct unilateral operations in the host countries. The FBI can and does at times carry out secret activities overseas, just as the CIA has a limited domestic function; these activities generally require coordination across government agencies. |
In 1939, the Bureau began compiling a custodial detention list with the names of those who would be taken into custody in the event of war with Axis nations. The majority of the names on the list belonged to Issei community leaders, as the FBI investigation built on an existing Naval Intelligence index that had focused on Japanese Americans in Hawaii and the West Coast, but many German and Italian nationals also found their way onto the secret list. Robert Shivers, head of the Honolulu office, obtained permission from Hoover to start detaining those on the list on December 7, 1941, while bombs were still falling over Pearl Harbor. Mass arrests and searches of homes (in most cases conducted without warrants) began a few hours after the attack, and over the next several weeks more than 5,500 Issei men were taken into FBI custody. On February 19, 1942, President Franklin Roosevelt issued Executive Order 9066, authorizing the removal of Japanese Americans from the West Coast. FBI Director Hoover opposed the subsequent mass removal and confinement of Japanese Americans authorized under Executive Order 9066, but Roosevelt prevailed. The vast majority went along with the subsequent exclusion orders, but in a handful of cases where Japanese Americans refused to obey the new military regulations, FBI agents handled their arrests. The Bureau continued surveillance on Japanese Americans throughout the war, conducting background checks on applicants for resettlement outside camp, and entering the camps (usually without the permission of War Relocation Authority officials) and grooming informants in order to monitor dissidents and "troublemakers." After the war, the FBI was assigned to protect returning Japanese Americans from attacks by hostile white communities. |
In response to organized crime, on August 25, 1953, the FBI created the Top Hoodlum Program. The national office directed field offices to gather information on mobsters in their territories and to report it regularly to Washington for a centralized collection of intelligence on racketeers. After the Racketeer Influenced and Corrupt Organizations Act, or RICO Act, took effect, the FBI began investigating the former Prohibition-organized groups, which had become fronts for crime in major cities and small towns. All of the FBI work was done undercover and from within these organizations, using the provisions provided in the RICO Act. Gradually the agency dismantled many of the groups. Although Hoover initially denied the existence of a National Crime Syndicate in the United States, the Bureau later conducted operations against known organized crime syndicates and families, including those headed by Sam Giancana and John Gotti. The RICO Act is still used today for all organized crime and any individuals who might fall under the Act. |
After Congress passed the Communications Assistance for Law Enforcement Act (CALEA, 1994), the Health Insurance Portability and Accountability Act (HIPAA, 1996), and the Economic Espionage Act (EEA, 1996), the FBI followed suit and underwent a technological upgrade in 1998, just as it did with its CART team in 1991. Computer Investigations and Infrastructure Threat Assessment Center (CITAC) and the National Infrastructure Protection Center (NIPC) were created to deal with the increase in Internet-related problems, such as computer viruses, worms, and other malicious programs that threatened US operations. With these developments, the FBI increased its electronic surveillance in public safety and national security investigations, adapting to the telecommunications advancements that changed the nature of such problems. |
For over 40 years, the FBI crime lab in Quantico believed lead in bullets had unique chemical signatures. It analyzed the bullets with the goal of matching them chemically, not only to a single batch of ammunition coming out of a factory, but also to a single box of bullets. The National Academy of Sciences conducted an 18-month independent review of comparative bullet-lead analysis. In 2003, its National Research Council published a report whose conclusions called into question 30 years of FBI testimony. It found the analytic model used by the FBI for interpreting results was deeply flawed, and the conclusion, that bullet fragments could be matched to a box of ammunition, was so overstated that it was misleading under the rules of evidence. One year later, the FBI decided to stop doing bullet lead analysis. |
The FBI's chief tool against organized crime is the Racketeer Influenced and Corrupt Organizations (RICO) Act. The FBI is also charged with the responsibility of enforcing compliance of the United States Civil Rights Act of 1964 and investigating violations of the act in addition to prosecuting such violations with the United States Department of Justice (DOJ). The FBI also shares concurrent jurisdiction with the Drug Enforcement Administration (DEA) in the enforcement of the Controlled Substances Act of 1970. |
The FBI often works in conjunction with other Federal agencies, including the U.S. Coast Guard (USCG) and U.S. Customs and Border Protection (CBP) in seaport and airport security, and the National Transportation Safety Board in investigating airplane crashes and other critical incidents. Immigration and Customs Enforcement Homeland Security Investigations (ICE-HSI) has nearly the same amount of investigative man power as the FBI, and investigates the largest range of crimes. In the wake of the September 11 attacks, then-Attorney General Ashcroft assigned the FBI as the designated lead organization in terrorism investigations after the creation of the U.S. Department of Homeland Security. ICE-HSI and the FBI are both integral members of the Joint Terrorism Task Force. |
The FBI Academy, located in Quantico, Virginia, is home to the communications and computer laboratory the FBI utilizes. It is also where new agents are sent for training to become FBI Special Agents. Going through the 21-week course is required for every Special Agent. First opened for use in 1972, the facility located on 385 acres (1.6 km2) of woodland. The Academy trains state and local law enforcement agencies, which are invited to the law enforcement training center. The FBI units that reside at Quantico are the Field and Police Training Unit, Firearms Training Unit, Forensic Science Research and Training Center, Technology Services Unit (TSU), Investigative Training Unit, Law Enforcement Communication Unit, Leadership and Management Science Units (LSMU), Physical Training Unit, New Agents' Training Unit (NATU), Practical Applications Unit (PAU), the Investigative Computer Training Unit and the "College of Analytical Studies." |
The FBI frequently investigated Martin Luther King, Jr. In the mid-1960s, King began publicly criticizing the Bureau for giving insufficient attention to the use of terrorism by white supremacists. Hoover responded by publicly calling King the most "notorious liar" in the United States. In his 1991 memoir, Washington Post journalist Carl Rowan asserted that the FBI had sent at least one anonymous letter to King encouraging him to commit suicide. Historian Taylor Branch documents an anonymous November 1964 "suicide package" sent by the Bureau that combined a letter to the civil rights leader telling him "You are done. There is only one way out for you..." with audio recordings of King's sexual indiscretions. |
The National Incident Based Reporting System (NIBRS) crime statistics system aims to address limitations inherent in UCR data. The system is used by law enforcement agencies in the United States for collecting and reporting data on crimes. Local, state, and federal agencies generate NIBRS data from their records management systems. Data is collected on every incident and arrest in the Group A offense category. The Group A offenses are 46 specific crimes grouped in 22 offense categories. Specific facts about these offenses are gathered and reported in the NIBRS system. In addition to the Group A offenses, eleven Group B offenses are reported with only the arrest information. The NIBRS system is in greater detail than the summary-based UCR system. As of 2004, 5,271 law enforcement agencies submitted NIBRS data. That amount represents 20% of the United States population and 16% of the crime statistics data collected by the FBI. |
The FBI also spied upon and collected information on Puerto Rican independence leader Pedro Albizu Campos and his Nationalist political party in the 1930s. Abizu Campos was convicted three times in connection with deadly attacks on US government officials: in 1937 (Conspiracy to overthrow the government of the United States), in 1950 (attempted murder), and in 1954 (after an armed assault on the US House of Representatives while in session; although not present, Abizu Campos was considered the mastermind). The FBI operation was covert and did not become known until U.S. Congressman Luis Gutierrez had it made public via the Freedom of Information Act in the 1980s. |
The FBI is organized into functional branches and the Office of the Director, which contains most administrative offices. An executive assistant director manages each branch. Each branch is then divided into offices and divisions, each headed by an assistant director. The various divisions are further divided into sub-branches, led by deputy assistant directors. Within these sub-branches there are various sections headed by section chiefs. Section chiefs are ranked analogous to special agents in charge. |
The FBI is headquartered at the J. Edgar Hoover Building in Washington, D.C., with 56 field offices in major cities across the United States. The FBI also maintains over 400 resident agencies across the United States, as well as over 50 legal attachés at United States embassies and consulates. Many specialized FBI functions are located at facilities in Quantico, Virginia, as well as a "data campus" in Clarksburg, West Virginia, where 96 million sets of fingerprints "from across the United States are stored, along with others collected by American authorities from prisoners in Saudi Arabia and Yemen, Iraq and Afghanistan." The FBI is in process of moving its Records Management Division, which processes Freedom of Information Act (FOIA) requests, to Winchester, Virginia. |
Carnivore was an electronic eavesdropping software system implemented by the FBI during the Clinton administration; it was designed to monitor email and electronic communications. After prolonged negative coverage in the press, the FBI changed the name of its system from "Carnivore" to "DCS1000." DCS is reported to stand for "Digital Collection System"; the system has the same functions as before. The Associated Press reported in mid-January 2005 that the FBI essentially abandoned the use of Carnivore in 2001, in favor of commercially available software, such as NarusInsight. |
FBI Directors are appointed by the President of the United States. They must be confirmed by the United States Senate and serve a term of office of five years, with a maximum of ten years, if reappointed, unless they resign or are fired by the President before their term ends. J. Edgar Hoover, appointed by Calvin Coolidge in 1924, was by far the longest-serving director, serving until his death in 1972. In 1968, Congress passed legislation as part of the Omnibus Crime Control and Safe Streets Act Pub.L. 90–351, June 19, 1968, 82 Stat. 197 that specified a 10-year limit, a maximum of two 5-year terms, for future FBI Directors, as well as requiring Senate confirmation of appointees. As the incumbent, this legislation did not apply to Hoover, only to his successors. The current FBI Director is James B. Comey, who was appointed in 2013 by Barack Obama. |
The FBI has been frequently depicted in popular media since the 1930s. The bureau has participated to varying degrees, which has ranged from direct involvement in the creative process of film or TV series development, to providing consultation on operations and closed cases. A few of the notable portrayals of the FBI on television are the 1993-2002 series The X-Files, which concerned investigations into paranormal phenomena by five fictional Special Agents and the fictional Counter Terrorist Unit (CTU) agency in the TV drama 24, which is patterned after the FBI Counterterrorism Division. The 1991 movie Point Break is based on the true story of an undercover FBI agent who infiltrated a gang of bank robbers. The 1997 movie Donnie Brasco is based on the true story of undercover FBI agent Joseph D. Pistone infiltrating the Mafia. |
During the period from 1993 to 2011, FBI agents fired their weapons on 289 occasions; FBI internal reviews found the shots justified in all but 5 cases, in none of the 5 cases were people wounded. Samuel Walker, a professor of criminal justice at the University of Nebraska Omaha said the number of shots found to be unjustified was "suspiciously low." In the same time period, the FBI wounded 150 people, 70 of whom died; the FBI found all 150 shootings to be justified. Likewise, during the period from 2011 to the present, all shootings by FBI agents have been found to be justified by internal investigation. In a 2002 case in Maryland, an innocent man was shot, and later paid $1.3 million by the FBI after agents mistook him for a bank robber; the internal investigation found that the shooting was justified, based on the man's actions. |
In 2005, fugitive Puerto Rican Nationalist leader Filiberto Ojeda Ríos died in a gun battle with FBI agents in 2005 in what some charged was an assassination.[citation needed] Puerto Rico Governor Aníbal Acevedo Vilá criticized the FBI assault as "improper" and "highly irregular" and demanded to know why his government was not informed of it. The FBI refused to release information beyond the official press release, citing security and agent privacy issues. The Puerto Rico Justice Department filed suit in federal court against the FBI and the US Attorney General, demanding information crucial to the Commonwealth's own investigation of the incident. The case was dismissed by the U.S Supreme Court. Ojeda Rios' funeral was attended by a long list of dignitaries, including the highest authority of the Roman Catholic Church in Puerto Rico, Archbishop Roberto Octavio González Nieves, ex-Governor Rafael Hernández Colón, and numerous other personalities. |
A thorough understanding of adolescence in society depends on information from various perspectives, including psychology, biology, history, sociology, education, and anthropology. Within all of these perspectives, adolescence is viewed as a transitional period between childhood and adulthood, whose cultural purpose is the preparation of children for adult roles. It is a period of multiple transitions involving education, training, employment and unemployment, as well as transitions from one living circumstance to another. |
Puberty occurs through a long process and begins with a surge in hormone production, which in turn causes a number of physical changes. It is the stage of life characterized by the appearance and development of secondary sex characteristics (for example, a deeper voice and larger adam's apple in boys, and development of breasts and more curved and prominent hips in girls) and a strong shift in hormonal balance towards an adult state. This is triggered by the pituitary gland, which secretes a surge of hormonal agents into the blood stream, initiating a chain reaction to occur. The male and female gonads are subsequently activated, which puts them into a state of rapid growth and development; the triggered gonads now commence the mass production of the necessary chemicals. The testes primarily release testosterone, and the ovaries predominantly dispense estrogen. The production of these hormones increases gradually until sexual maturation is met. Some boys may develop gynecomastia due to an imbalance of sex hormones, tissue responsiveness or obesity. |
Pubertal development also affects circulatory and respiratory systems as an adolescents' heart and lungs increase in both size and capacity. These changes lead to increased strength and tolerance for exercise. Sex differences are apparent as males tend to develop "larger hearts and lungs, higher systolic blood pressure, a lower resting heart rate, a greater capacity for carrying oxygen to the blood, a greater power for neutralizing the chemical products of muscular exercise, higher blood hemoglobin and more red blood cells". |
The human brain is not fully developed by the time a person reaches puberty. Between the ages of 10 and 25, the brain undergoes changes that have important implications for behavior (see Cognitive development below). The brain reaches 90% of its adult size by the time a person is six years of age. Thus, the brain does not grow in size much during adolescence. However, the creases in the brain continue to become more complex until the late teens. The biggest changes in the folds of the brain during this time occur in the parts of the cortex that process cognitive and emotional information. |
Serotonin is a neuromodulator involved in regulation of mood and behavior. Development in the limbic system plays an important role in determining rewards and punishments and processing emotional experience and social information. Changes in the levels of the neurotransmitters dopamine and serotonin in the limbic system make adolescents more emotional and more responsive to rewards and stress. The corresponding increase in emotional variability also can increase adolescents' vulnerability. The effect of serotonin is not limited to the limbic system: Several serotonin receptors have their gene expression change dramatically during adolescence, particularly in the human frontal and prefrontal cortex . |
Adolescents' thinking is less bound to concrete events than that of children: they can contemplate possibilities outside the realm of what currently exists. One manifestation of the adolescent's increased facility with thinking about possibilities is the improvement of skill in deductive reasoning, which leads to the development of hypothetical thinking. This provides the ability to plan ahead, see the future consequences of an action and to provide alternative explanations of events. It also makes adolescents more skilled debaters, as they can reason against a friend's or parent's assumptions. Adolescents also develop a more sophisticated understanding of probability. |
The timing of puberty can have important psychological and social consequences. Early maturing boys are usually taller and stronger than their friends. They have the advantage in capturing the attention of potential partners and in becoming hand-picked for sports. Pubescent boys often tend to have a good body image, are more confident, secure, and more independent. Late maturing boys can be less confident because of poor body image when comparing themselves to already developed friends and peers. However, early puberty is not always positive for boys; early sexual maturation in boys can be accompanied by increased aggressiveness due to the surge of hormones that affect them. Because they appear older than their peers, pubescent boys may face increased social pressure to conform to adult norms; society may view them as more emotionally advanced, despite the fact that their cognitive and social development may lag behind their appearance. Studies have shown that early maturing boys are more likely to be sexually active and are more likely to participate in risky behaviors. |
Wisdom, or the capacity for insight and judgment that is developed through experience, increases between the ages of fourteen and twenty-five, then levels off. Thus, it is during the adolescence-adulthood transition that individuals acquire the type of wisdom that is associated with age. Wisdom is not the same as intelligence: adolescents do not improve substantially on IQ tests since their scores are relative to others in their same age group, and relative standing usually does not change—everyone matures at approximately the same rate in this way. |
In studying adolescent development, adolescence can be defined biologically, as the physical transition marked by the onset of puberty and the termination of physical growth; cognitively, as changes in the ability to think abstractly and multi-dimensionally; or socially, as a period of preparation for adult roles. Major pubertal and biological changes include changes to the sex organs, height, weight, and muscle mass, as well as major changes in brain structure and organization. Cognitive advances encompass both increases in knowledge and in the ability to think abstractly and to reason more effectively. The study of adolescent development often involves interdisciplinary collaborations. For example, researchers in neuroscience or bio-behavioral health might focus on pubertal changes in brain structure and its effects on cognition or social relations. Sociologists interested in adolescence might focus on the acquisition of social roles (e.g., worker or romantic partner) and how this varies across cultures or social conditions. Developmental psychologists might focus on changes in relations with parents and peers as a function of school structure and pubertal status. |
Jean Macfarlane founded the University of California, Berkeley's Institute of Human Development, formerly called the Institute of Child Welfare, in 1927. The Institute was instrumental in initiating studies of healthy development, in contrast to previous work that had been dominated by theories based on pathological personalities. The studies looked at human development during the Great Depression and World War II, unique historical circumstances under which a generation of children grew up. The Oakland Growth Study, initiated by Harold Jones and Herbert Stolz in 1931, aimed to study the physical, intellectual, and social development of children in the Oakland area. Data collection began in 1932 and continued until 1981, allowing the researchers to gather longitudinal data on the individuals that extended past adolescence into adulthood. Jean Macfarlane launched the Berkeley Guidance Study, which examined the development of children in terms of their socioeconomic and family backgrounds. These studies provided the background for Glen Elder in the 1960s, to propose a life-course perspective of adolescent development. Elder formulated several descriptive principles of adolescent development. The principle of historical time and place states that an individual's development is shaped by the period and location in which they grow up. The principle of the importance of timing in one's life refers to the different impact that life events have on development based on when in one's life they occur. The idea of linked lives states that one's development is shaped by the interconnected network of relationships of which one is a part; and the principle of human agency asserts that one's life course is constructed via the choices and actions of an individual within the context of their historical period and social network. |
The major landmark of puberty for males is the first ejaculation, which occurs, on average, at age 13. For females, it is menarche, the onset of menstruation, which occurs, on average, between ages 12 and 13. The age of menarche is influenced by heredity, but a girl's diet and lifestyle contribute as well. Regardless of genes, a girl must have a certain proportion of body fat to attain menarche. Consequently, girls who have a high-fat diet and who are not physically active begin menstruating earlier, on average, than girls whose diet contains less fat and whose activities involve fat reducing exercise (e.g. ballet and gymnastics). Girls who experience malnutrition or are in societies in which children are expected to perform physical labor also begin menstruating at later ages. |
Adolescents can conceptualize multiple "possible selves" that they could become and long-term possibilities and consequences of their choices. Exploring these possibilities may result in abrupt changes in self-presentation as the adolescent chooses or rejects qualities and behaviors, trying to guide the actual self toward the ideal self (who the adolescent wishes to be) and away from the feared self (who the adolescent does not want to be). For many, these distinctions are uncomfortable, but they also appear to motivate achievement through behavior consistent with the ideal and distinct from the feared possible selves. |
In females, changes in the primary sex characteristics involve growth of the uterus, vagina, and other aspects of the reproductive system. Menarche, the beginning of menstruation, is a relatively late development which follows a long series of hormonal changes. Generally, a girl is not fully fertile until several years after menarche, as regular ovulation follows menarche by about two years. Unlike males, therefore, females usually appear physically mature before they are capable of becoming pregnant. |
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