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There are no nephridia ("little kidneys") or other excretory organs in bryozoa, and it is thought that ammonia diffuses out through the body wall and lophophore. More complex waste products are not excreted but accumulate in the polypide, which degenerates after a few weeks. Some of the old polypide is recycled, but mu... | Bryozoa | Wikipedia | 312 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Zooids of all phylactolaemate species are simultaneous hermaphrodites. Although those of many marine species are protandric, in other words function first as males and then as females, their colonies contain a combination of zooids that are in their male and female stages. In all species the ovaries develop on the insi... | Bryozoa | Wikipedia | 421 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Planktotrophic (feeding) larvae are only found in class Gymnolaemata: In the cheilostomatan suborder Malacostegina they are found in the two families Membraniporidae and Electridae, and in the three ctenostome families Alcyonidiidae, Farrellidae, and Hislopiidae. In addition there are a few unconfirmed records, like th... | Bryozoa | Wikipedia | 215 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Bryozoan larvae vary in form, but all have a band of cilia round the body which enables them to swim, a tuft of cilia at the top, and an adhesive sac that everts and anchors them when they settle on a surface. Some gymnolaemate species produce cyphonautes larvae which have little yolk but a well-developed mouth and gut... | Bryozoa | Wikipedia | 327 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Phylactolaemates can also reproduce asexually by a method that enables a colony's lineage to survive the variable and uncertain conditions of freshwater environments. Throughout summer and autumn they produce disc-shaped statoblasts, masses of cells that function as "survival pods" rather like the gemmules of sponges. ... | Bryozoa | Wikipedia | 508 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
The great majority of bryozoans are sessile. Typically, sessile bryozoans live on hard substrates including rocks, sand or shells. Boring bryozoans leave unique borehole traces after dissolving calcium carbonate substrates. Encrusting forms are much the commonest of these in shallow seas, but erect forms become more co... | Bryozoa | Wikipedia | 420 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Other free-living bryozoans are moved freely by waves, currents, or other phenomena. An Antarctic species, Alcyonidium pelagosphaera, consists of floating colonies. The pelagic species is between in diameter, has the shape of a hollow sphere and consists of a single layer of autozooids. It is still not known if these ... | Bryozoa | Wikipedia | 361 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Bryozoans grow in clonal colonies. A larval Bryozoan settles on a hard substance and produces a colony asexually through budding. These colonies can grow thousands of individual zooids in a relatively short period of time. Even though colonies of zooids grow through asexual reproduction, Bryozoans are hermaphrodites an... | Bryozoa | Wikipedia | 468 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Several species of the hydroid family Zancleidae have symbiotic relationships with bryozoans, some of which are beneficial to the hydroids while others are parasitic. Modifications appear in the shapes of some these hydroids, for example smaller tentacles or encrustation of the roots by bryozoans. The bryozoan Alcyonid... | Bryozoa | Wikipedia | 502 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
Interaction with humans
Fish farms and hatcheries have lost stock to proliferative kidney disease, which is caused by one or more myxozoans that use bryozoans as alternate hosts.
Some fishermen in the North Sea have had to find other work because of a form of eczema (a skin disease) known as "Dogger Bank itch", cause... | Bryozoa | Wikipedia | 363 | 3416 | https://en.wikipedia.org/wiki/Bryozoa | Biology and health sciences | Lophotrochozoa | null |
The bay leaf is an aromatic leaf commonly used as a herb in cooking. It can be used whole, either dried or fresh, in which case it is removed from the dish before consumption, or less commonly used in ground form. The flavor that a bay leaf imparts to a dish has not been universally agreed upon, but many agree it is a ... | Bay leaf | Wikipedia | 336 | 3419 | https://en.wikipedia.org/wiki/Bay%20leaf | Biology and health sciences | Herbs and spices | Plants |
Sources
Bay leaves come from several plants, such as:
Bay laurel (Laurus nobilis, Lauraceae). Fresh or dried bay leaves are used in cooking for their distinctive flavour and fragrance. The leaves should be removed from the cooked food before eating (see safety section below). The leaves are often used to flavour soup... | Bay leaf | Wikipedia | 489 | 3419 | https://en.wikipedia.org/wiki/Bay%20leaf | Biology and health sciences | Herbs and spices | Plants |
Taste and aroma
If eaten whole, Laurus nobilis bay leaves are pungent and have a sharp, bitter taste. As with many spices and flavourings, the fragrance of the bay leaf is more noticeable than its taste. When the leaf is dried, the aroma is herbal, slightly floral, and somewhat similar to oregano and thyme. Myrcene, a ... | Bay leaf | Wikipedia | 471 | 3419 | https://en.wikipedia.org/wiki/Bay%20leaf | Biology and health sciences | Herbs and spices | Plants |
Bay leaves are also used in the making of jerk chicken in the Caribbean Islands. The bay leaves are soaked and placed on the cool side of the grill. Pimento sticks are placed on top of the leaves, and the chicken is placed on top and smoked. The leaves are also added whole to soups, stews, and other Caribbean dishes.
... | Bay leaf | Wikipedia | 434 | 3419 | https://en.wikipedia.org/wiki/Bay%20leaf | Biology and health sciences | Herbs and spices | Plants |
Safety
Some members of the laurel family, as well as the unrelated but visually similar mountain laurel and cherry laurel, have leaves that are poisonous to humans and livestock. While these plants are not sold anywhere for culinary use, their visual similarity to bay leaves has led to the oft-repeated belief that bay ... | Bay leaf | Wikipedia | 221 | 3419 | https://en.wikipedia.org/wiki/Bay%20leaf | Biology and health sciences | Herbs and spices | Plants |
A bulletin board system (BBS), also called a computer bulletin board service (CBBS), is a computer server running software that allows users to connect to the system using a terminal program. Once logged in, the user performs functions such as uploading and downloading software and data, reading news and bulletins, and... | Bulletin board system | Wikipedia | 506 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
Community Memory allowed the user to type messages into a computer terminal after inserting a coin, and offered a "pure" bulletin board experience with public messages only (no email or other features). It did offer the ability to tag messages with keywords, which the user could use in searches. The system acted primar... | Bulletin board system | Wikipedia | 489 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
The first public dial-up BBS was developed by Ward Christensen and Randy Suess, members of the Chicago Area Computer Hobbyists' Exchange (CACHE). According to an early interview, when Chicago was snowed under during the Great Blizzard of 1978, the two began preliminary work on the Computerized Bulletin Board System, or... | Bulletin board system | Wikipedia | 494 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
The introduction of the Smartmodem led to the first real wave of BBS systems. Limited in speed and storage capacity, these systems were normally dedicated solely to messaging, private email and public forums. File transfers were extremely slow at these speeds, and file libraries were typically limited to text files con... | Bulletin board system | Wikipedia | 349 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
This also gave rise to a new class of BBS systems, dedicated solely to file upload and downloads. These systems charged for access, typically a flat monthly fee, compared to the per-hour fees charged by Event Horizons BBS and most online services. Many third-party services were developed to support these systems, offer... | Bulletin board system | Wikipedia | 360 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
A number of systems also made forays into GUI-based interfaces, either using character graphics sent from the host, or using custom GUI-based terminal systems. The latter initially appeared on the Macintosh platform, where TeleFinder and FirstClass became very popular. FirstClass offered a host of features that would b... | Bulletin board system | Wikipedia | 478 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
These increasing speeds had the side effect of dramatically reducing the noticeable effects of channel efficiency. When modems were slow, considerable effort was put into developing the most efficient protocols and display systems possible. TCP/IP ran slowly over 1200 bit/s modems. 56 kbit/s modems could access the pro... | Bulletin board system | Wikipedia | 475 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
In the 2000s, most traditional BBS systems migrated to the Internet using Telnet or SSH protocols. As of September 2022, between 900 and 1000 are thought to be active via the Internet fewer than 30 of these being of the traditional "dial-up" (modem) variety.
Software and hardware
Unlike modern websites and online se... | Bulletin board system | Wikipedia | 408 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
BBS systems on other systems remained popular, especially home computers, largely because they catered to the audience of users running those machines. The ubiquitous Commodore 64 (introduced in 1982) was a common platform in the 1980s. Popular commercial BBS programs were Blue Board, Ivory BBS, Color64 and CNet 64. Th... | Bulletin board system | Wikipedia | 422 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
By 1995, many of the DOS-based BBSes had begun switching to modern multitasking operating systems, such as OS/2, Windows 95, and Linux. One of the first graphics-based BBS applications was Excalibur BBS with low-bandwidth applications that required its own client for efficiency. This led to one of the earliest implemen... | Bulletin board system | Wikipedia | 405 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
COCONET, a BBS system made by Coconut Computing, Inc., was released in 1988 and only supported a GUI (no text interface was initially available but eventually became available around 1990), and worked in EGA/VGA graphics mode, which made it stand out from text-based BBS systems. COCONET's bitmap and vector graphics and... | Bulletin board system | Wikipedia | 504 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
Today, most BBS software that is still actively supported, such as Worldgroup, Wildcat! BBS and Citadel/UX, is Web-enabled, and the traditional text interface has been replaced (or operates concurrently) with a Web-based user interface. For those more nostalgic for the true BBS experience, one can use NetSerial (Window... | Bulletin board system | Wikipedia | 508 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
Some BBSes, called elite, WaReZ, or pirate boards, were exclusively used for distributing cracked software, phreaking materials, and other questionable or unlawful content. These BBSes often had multiple modems and phone lines, allowing several users to upload and download files at once. Most elite BBSes used some form... | Bulletin board system | Wikipedia | 500 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
Most early BBSes operated as individual systems. Information contained on that BBS never left the system, and users would only interact with the information and user community on that BBS alone. However, as BBSes became more widespread, there evolved a desire to connect systems together to share messages and files with... | Bulletin board system | Wikipedia | 339 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
FidoNet was platform-independent and would work with any BBS that was written to use it. BBSes that did not have integrated FidoNet capability could usually add it using an external FidoNet front-end mailer such as SEAdog, FrontDoor, BinkleyTerm, InterMail or D'Bridge, and a mail processor such as FastEcho or Squish. T... | Bulletin board system | Wikipedia | 478 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
FidoNet is still in use today, though in a much smaller form, and many Echomail groups are still shared with Usenet via FidoNet to Usenet gateways. Widespread abuse of Usenet with spam and pornography has led to many of these FidoNet gateways to cease operation completely.
Shareware and freeware
Much of the shareware... | Bulletin board system | Wikipedia | 317 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
The BBS software usually provides:
Menu systems
One or more message bases
Uploading and downloading of message packets in QWK format using XMODEM, YMODEM or ZMODEM
File areas
Live viewing of all caller activity by the system operator
Voting – opinion booths
Statistics on message posters, top uploaders / downloa... | Bulletin board system | Wikipedia | 208 | 3430 | https://en.wikipedia.org/wiki/Bulletin%20board%20system | Technology | Internet | null |
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing and olfaction. Being the most specialized organ, it is... | Brain | Wikipedia | 435 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Physiologically, brains exert centralized control over a body's other organs. They act on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Some bas... | Brain | Wikipedia | 358 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The simplest way to gain information about brain anatomy is by visual inspection, but many more sophisticated techniques have been developed. Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interi... | Brain | Wikipedia | 161 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The brains of all species are composed primarily of two broad classes of brain cells: neurons and glial cells. Glial cells (also known as glia or neuroglia) come in several types, and perform a number of critical functions, including structural support, metabolic support, insulation, and guidance of development. Neuron... | Brain | Wikipedia | 445 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Synapses are the key functional elements of the brain. The essential function of the brain is cell-to-cell communication, and synapses are the points at which communication occurs. The human brain has been estimated to contain approximately 100 trillion synapses; even the brain of a fruit fly contains several million. ... | Brain | Wikipedia | 297 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Except for a few primitive organisms such as sponges (which have no nervous system) and cnidarians (which have a diffuse nervous system consisting of a nerve net), all living multicellular animals are bilaterians, meaning animals with a bilaterally symmetric body plan (that is, left and right sides that are approximate... | Brain | Wikipedia | 402 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Two groups of invertebrates have notably complex brains: arthropods (insects, crustaceans, arachnids, and others), and cephalopods (octopuses, squids, and similar molluscs). The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. Arthropods have a centra... | Brain | Wikipedia | 127 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
There are several invertebrate species whose brains have been studied intensively because they have properties that make them convenient for experimental work:
Fruit flies (Drosophila), because of the large array of techniques available for studying their genetics, have been a natural subject for studying the role of ... | Brain | Wikipedia | 459 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The first vertebrates appeared over 500 million years ago (Mya) during the Cambrian period, and may have resembled the modern jawless fish (hagfish and lamprey) in form. Jawed vertebrates appeared by 445 Mya, tetrapods by 350 Mya, amniotes by 310 Mya and mammaliaforms by 200 Mya (approximately). Each vertebrate clade h... | Brain | Wikipedia | 355 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three vesicular swellings at the front end of the neural tube; these swellings eventually become the forebrain (prosencephalon), midbrain (mesencephal... | Brain | Wikipedia | 429 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Neuroanatomists usually divide the vertebrate brain into six main subregions: the telencephalon (the cerebral hemispheres), diencephalon (thalamus and hypothalamus), mesencephalon (midbrain), cerebellum, pons and medulla oblongata, with the midbrain, pons and medulla often collectively called the brainstem. Each of the... | Brain | Wikipedia | 349 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The medulla, along with the spinal cord, contains many small nuclei involved in a wide variety of sensory and involuntary motor functions such as vomiting, heart rate and digestive processes.
The pons lies in the brainstem directly above the medulla. Among other things, it contains nuclei that control often voluntary ... | Brain | Wikipedia | 507 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The pallium is a layer of grey matter that lies on the surface of the forebrain and is the most complex and most recent evolutionary development of the brain as an organ. In reptiles and mammals, it is called the cerebral cortex. Multiple functions involve the pallium, including smell and spatial memory. In mammals, wh... | Brain | Wikipedia | 366 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Reptiles
Modern reptiles and mammals diverged from a common ancestor around 320 million years ago. The number of extant reptiles far exceeds the number of mammalian species, with 11,733 recognized species of reptiles compared to 5,884 extant mammals. Along with the species diversity, reptiles have diverged in terms o... | Brain | Wikipedia | 382 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Anatomically, the reptilian brain has less subdivisions than the mammalian brain, however it has numerous conserved aspects including the organization of the spinal cord and cranial nerve, as well as elaborated brain pattern of organization. Elaborated brains are characterized by migrated neuronal cell bodies away from... | Brain | Wikipedia | 462 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure. The cerebral cortex is the par... | Brain | Wikipedia | 421 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Most of the enlargement of the primate brain comes from a massive expansion of the cerebral cortex, especially the prefrontal cortex and the parts of the cortex involved in vision. The visual processing network of primates includes at least 30 distinguishable brain areas, with a complex web of interconnections. It has ... | Brain | Wikipedia | 280 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
For vertebrates, the early stages of neural development are similar across all species. As the embryo transforms from a round blob of cells into a wormlike structure, a narrow strip of ectoderm running along the midline of the back is induced to become the neural plate, the precursor of the nervous system. The neural p... | Brain | Wikipedia | 487 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The synaptic network that finally emerges is only partly determined by genes, though. In many parts of the brain, axons initially "overgrow", and then are "pruned" by mechanisms that depend on neural activity. In the projection from the eye to the midbrain, for example, the structure in the adult contains a very precis... | Brain | Wikipedia | 371 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
In humans and many other mammals, new neurons are created mainly before birth, and the infant brain contains substantially more neurons than the adult brain. There are, however, a few areas where new neurons continue to be generated throughout life. The two areas for which adult neurogenesis is well established are the... | Brain | Wikipedia | 366 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Neurotransmitters and receptors
Neurotransmitters are chemicals that are released at synapses when the local membrane is depolarised and Ca2+ enters into the cell, typically when an action potential arrives at the synapse – neurotransmitters attach themselves to receptor molecules on the membrane of the synapse's targ... | Brain | Wikipedia | 499 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
As a side effect of the electrochemical processes used by neurons for signaling, brain tissue generates electric fields when it is active. When large numbers of neurons show synchronized activity, the electric fields that they generate can be large enough to detect outside the skull, using electroencephalography (EEG) ... | Brain | Wikipedia | 337 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Brain tissue consumes a large amount of energy in proportion to its volume, so large brains place severe metabolic demands on animals. The need to limit body weight in order, for example, to fly, has apparently led to selection for a reduction of brain size in some species, such as bats. Most of the brain's energy cons... | Brain | Wikipedia | 485 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Each sensory system begins with specialized receptor cells, such as photoreceptor cells in the retina of the eye, or vibration-sensitive hair cells in the cochlea of the ear. The axons of sensory receptor cells travel into the spinal cord or brain, where they transmit their signals to a first-order sensory nucleus dedi... | Brain | Wikipedia | 499 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Many animals alternate between sleeping and waking in a daily cycle. Arousal and alertness are also modulated on a finer time scale by a network of brain areas. A key component of the sleep system is the suprachiasmatic nucleus (SCN), a tiny part of the hypothalamus located directly above the point at which the optic n... | Brain | Wikipedia | 502 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
For any animal, survival requires maintaining a variety of parameters of bodily state within a limited range of variation: these include temperature, water content, salt concentration in the bloodstream, blood glucose levels, blood oxygen level, and others. The ability of an animal to regulate the internal environment ... | Brain | Wikipedia | 401 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The individual animals need to express survival-promoting behaviors, such as seeking food, water, shelter, and a mate. The motivational system in the brain monitors the current state of satisfaction of these goals, and activates behaviors to meet any needs that arise. The motivational system works largely by a reward–p... | Brain | Wikipedia | 392 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Learning and memory
Almost all animals are capable of modifying their behavior as a result of experience—even the most primitive types of worms. Because behavior is driven by brain activity, changes in behavior must somehow correspond to changes inside the brain. Already in the late 19th century theorists like Santiag... | Brain | Wikipedia | 270 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Working memory is the ability of the brain to maintain a temporary representation of information about the task that an animal is currently engaged in. This sort of dynamic memory is thought to be mediated by the formation of cell assemblies—groups of activated neurons that maintain their activity by constantly stimula... | Brain | Wikipedia | 371 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The oldest method of studying the brain is anatomical, and until the middle of the 20th century, much of the progress in neuroscience came from the development of better cell stains and better microscopes. Neuroanatomists study the large-scale structure of the brain as well as the microscopic structure of neurons and t... | Brain | Wikipedia | 367 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Another approach to brain function is to examine the consequences of damage to specific brain areas. Even though it is protected by the skull and meninges, surrounded by cerebrospinal fluid, and isolated from the bloodstream by the blood–brain barrier, the delicate nature of the brain makes it vulnerable to numerous di... | Brain | Wikipedia | 452 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Recent years have also seen rapid advances in single-cell sequencing technologies, and these have been used to leverage the cellular heterogeneity of the brain as a means of better understanding the roles of distinct cell types in disease and biology (as well as how genomic variants influence individual cell types). In... | Brain | Wikipedia | 433 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
The Roman physician Galen also argued for the importance of the brain, and theorized in some depth about how it might work. Galen traced out the anatomical relationships among brain, nerves, and muscles, demonstrating that all muscles in the body are connected to the brain through a branching network of nerves. He post... | Brain | Wikipedia | 425 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
In the first half of the 20th century, advances in electronics enabled investigation of the electrical properties of nerve cells, culminating in work by Alan Hodgkin, Andrew Huxley, and others on the biophysics of the action potential, and the work of Bernard Katz and others on the electrochemistry of the synapse. Thes... | Brain | Wikipedia | 451 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Theorists have worked to understand these response patterns by constructing mathematical models of neurons and neural networks, which can be simulated using computers. Some useful models are abstract, focusing on the conceptual structure of neural algorithms rather than the details of how they are implemented in the br... | Brain | Wikipedia | 482 | 3717 | https://en.wikipedia.org/wiki/Brain | Biology and health sciences | Biology | null |
Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limited to 2.5 milliwatts, giving it a very short range of up to . It employs UHF... | Bluetooth | Wikipedia | 492 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
The Bluetooth logo is a bind rune merging the Younger Futhark runes (ᚼ, Hagall) and (ᛒ, Bjarkan), Harald's initials.
History
The development of the "short-link" radio technology, later named Bluetooth, was initiated in 1989 by Nils Rydbeck, CTO at Ericsson Mobile in Lund, Sweden. The purpose was to develop wirele... | Bluetooth | Wikipedia | 416 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
The first Bluetooth device was revealed in 1999. It was a hands-free mobile headset that earned the "Best of show Technology Award" at COMDEX. The first Bluetooth mobile phone was the unreleased prototype Ericsson T36, though it was the revised Ericsson model T39 that actually made it to store shelves in June 2001. How... | Bluetooth | Wikipedia | 464 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Implementation
Bluetooth operates at frequencies between 2.402 and 2.480GHz, or 2.400 and 2.4835GHz, including guard bands 2MHz wide at the bottom end and 3.5MHz wide at the top. This is in the globally unlicensed (but not unregulated) industrial, scientific and medical (ISM) 2.4GHz short-range radio frequency band. B... | Bluetooth | Wikipedia | 377 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Bluetooth is a packet-based protocol with a master/slave architecture. One master may communicate with up to seven slaves in a piconet. All devices within a given piconet use the clock provided by the master as the base for packet exchange. The master clock ticks with a period of 312.5μs, two clock ticks then make up a... | Bluetooth | Wikipedia | 464 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Uses
Bluetooth is a standard wire-replacement communications protocol primarily designed for low power consumption, with a short range based on low-cost transceiver microchips in each device. Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other... | Bluetooth | Wikipedia | 495 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Profiles are definitions of possible applications and specify general behaviors that Bluetooth-enabled devices use to communicate with other Bluetooth devices. These profiles include settings to parameterize and to control the communication from the start. Adherence to profiles saves the time for transmitting the param... | Bluetooth | Wikipedia | 87 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Wireless control and communication between a mobile phone and a handsfree headset. This was one of the earliest applications to become popular.
Wireless control of audio and communication functions between a mobile phone and a Bluetooth compatible car stereo system (and sometimes between the SIM card and the car phone... | Bluetooth | Wikipedia | 487 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Personal security application on mobile phones for prevention of theft or loss of items. The protected item has a Bluetooth marker (e.g., a tag) that is in constant communication with the phone. If the connection is broken (the marker is out of range of the phone) then an alarm is raised. This can also be used as a man... | Bluetooth | Wikipedia | 162 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Devices
Bluetooth exists in numerous products such as telephones, speakers, tablets, media players, robotics systems, laptops, and game console equipment as well as some high definition headsets, modems, hearing aids and even watches. Bluetooth is useful when transferring information between two or more devices that ... | Bluetooth | Wikipedia | 267 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
For Microsoft platforms, Windows XP Service Pack 2 and SP3 releases work natively with Bluetooth v1.1, v2.0 and v2.0+EDR. Previous versions required users to install their Bluetooth adapter's own drivers, which were not directly supported by Microsoft. Microsoft's own Bluetooth dongles (packaged with their Bluetooth co... | Bluetooth | Wikipedia | 487 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Specifications and features
The specifications were formalized by the Bluetooth Special Interest Group (SIG) and formally announced on 20 May 1998. In 2014 it had a membership of over 30,000 companies worldwide. It was established by Ericsson, IBM, Intel, Nokia and Toshiba, and later joined by many other companies.
A... | Bluetooth | Wikipedia | 506 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
The specification is published as Bluetooth v2.0 + EDR, which implies that EDR is an optional feature. Aside from EDR, the v2.0 specification contains other minor improvements, and products may claim compliance to "Bluetooth v2.0" without supporting the higher data rate. At least one commercial device states "Bluetooth... | Bluetooth | Wikipedia | 399 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
L2CAP Enhanced modes Enhanced Retransmission Mode (ERTM) implements reliable L2CAP channel, while Streaming Mode (SM) implements unreliable channel with no retransmission or flow control. Introduced in Core Specification Addendum 1.
Alternative MAC/PHY Enables the use of alternative MAC and PHYs for transporting Bluet... | Bluetooth | Wikipedia | 414 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
On 16 March 2009, the WiMedia Alliance announced it was entering into technology transfer agreements for the WiMedia Ultra-wideband (UWB) specifications. WiMedia has transferred all current and future specifications, including work on future high-speed and power-optimized implementations, to the Bluetooth Special Inter... | Bluetooth | Wikipedia | 471 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
In a single-mode implementation, only the low energy protocol stack is implemented. Dialog Semiconductor, STMicroelectronics, AMICCOM, CSR, Nordic Semiconductor and Texas Instruments have released single mode Bluetooth Low Energy solutions.
In a dual-mode implementation, Bluetooth Smart functionality is integrated int... | Bluetooth | Wikipedia | 506 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Bluetooth 4.2
Released on 2 December 2014, it introduces features for the Internet of things.
The major areas of improvement are:
Bluetooth Low Energy Secure Connection with Data Packet Length Extension to improve the cryptographic protocol
Link Layer Privacy with Extended Scanner Filter Policies to improve data se... | Bluetooth | Wikipedia | 458 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
The major areas of improvement are:
Angle of arrival (AoA) and Angle of Departure (AoD) which are used for locating and tracking of devices
Advertising Channel Index
GATT caching
Minor Enhancements batch 1:
HCI support for debug keys in LE Secure Connections
Sleep clock accuracy update mechanism
ADI field in sca... | Bluetooth | Wikipedia | 480 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Bluetooth 5.4
The Bluetooth SIG released the Bluetooth Core Specification version 5.4 on 7 February 2023. This new version adds the following features:
Periodic Advertising with Responses (PAwR)
Encrypted Advertising Data
LE Security Levels Characteristic
Advertising Coding Selection
Bluetooth 6.0
The Bluetoot... | Bluetooth | Wikipedia | 483 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Bluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols. Mandatory protocols for all Bluetooth stacks are LMP, L2CAP and SDP. In addition, devices that communicate with Bluetooth almost universally can use these ... | Bluetooth | Wikipedia | 463 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Reliability in any of these modes is optionally and/or additionally guaranteed by the lower layer Bluetooth BDR/EDR air interface by configuring the number of retransmissions and flush timeout (time after which the radio flushes packets). In-order sequencing is guaranteed by the lower layer.
Only L2CAP channels config... | Bluetooth | Wikipedia | 459 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Audio/Video Control Transport Protocol
The Audio/Video Control Transport Protocol (AVCTP) is used by the remote control profile to transfer AV/C commands over an L2CAP channel. The music control buttons on a stereo headset use this protocol to control the music player.
Audio/Video Distribution Transport Protocol
The... | Bluetooth | Wikipedia | 461 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Any device may perform an inquiry to find other devices to connect to, and any device can be configured to respond to such inquiries. However, if the device trying to connect knows the address of the device, it always responds to direct connection requests and transmits the information shown in the list above if reques... | Bluetooth | Wikipedia | 507 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Implementation
During pairing, the two devices establish a relationship by creating a shared secret known as a link key. If both devices store the same link key, they are said to be paired or bonded. A device that wants to communicate only with a bonded device can cryptographically authenticate the identity of the oth... | Bluetooth | Wikipedia | 205 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Pairing mechanisms
Pairing mechanisms changed significantly with the introduction of Secure Simple Pairing in Bluetooth v2.1. The following summarizes the pairing mechanisms:
Legacy pairing: This is the only method available in Bluetooth v2.0 and before. Each device must enter a PIN code; pairing is only successful i... | Bluetooth | Wikipedia | 434 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Numeric comparison: If both devices have a display, and at least one can accept a binary yes/no user input, they may use Numeric Comparison. This method displays a 6-digit numeric code on each device. The user should compare the numbers to ensure they are identical. If the comparison succeeds, the user(s) should confir... | Bluetooth | Wikipedia | 273 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
SSP is considered simple for the following reasons:
In most cases, it does not require a user to generate a passkey.
For use cases not requiring MITM protection, user interaction can be eliminated.
For numeric comparison, MITM protection can be achieved with a simple equality comparison by the user.
Using OOB with ... | Bluetooth | Wikipedia | 480 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
In September 2008, the National Institute of Standards and Technology (NIST) published a Guide to Bluetooth Security as a reference for organizations. It describes Bluetooth security capabilities and how to secure Bluetooth technologies effectively. While Bluetooth has its benefits, it is susceptible to denial-of-servi... | Bluetooth | Wikipedia | 315 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
2001–2004
In 2001, Jakobsson and Wetzel from Bell Laboratories discovered flaws in the Bluetooth pairing protocol and also pointed to vulnerabilities in the encryption scheme. In 2003, Ben and Adam Laurie from A.L. Digital Ltd. discovered that serious flaws in some poor implementations of Bluetooth security may lead t... | Bluetooth | Wikipedia | 504 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
In April 2005, University of Cambridge security researchers published results of their actual implementation of passive attacks against the PIN-based pairing between commercial Bluetooth devices. They confirmed that attacks are practicably fast, and the Bluetooth symmetric key establishment method is vulnerable. To rec... | Bluetooth | Wikipedia | 435 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
2017
In April 2017, security researchers at Armis discovered multiple exploits in the Bluetooth software in various platforms, including Microsoft Windows, Linux, Apple iOS, and Google Android. These vulnerabilities are collectively called "BlueBorne". The exploits allow an attacker to connect to devices or systems wi... | Bluetooth | Wikipedia | 462 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Bluetooth uses the radio frequency spectrum in the 2.402GHz to 2.480GHz range, which is non-ionizing radiation, of similar bandwidth to that used by wireless and mobile phones. No specific harm has been demonstrated, even though wireless transmission has been included by IARC in the possible carcinogen list. Maximum po... | Bluetooth | Wikipedia | 278 | 3742 | https://en.wikipedia.org/wiki/Bluetooth | Technology | Networks | null |
Boron is a chemical element. It has the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three valence electrons for forming covalent bonds, resulting in many compounds such as b... | Boron | Wikipedia | 502 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
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