text stringlengths 26 3.6k | page_title stringlengths 1 71 | source stringclasses 1
value | token_count int64 10 512 | id stringlengths 2 8 | url stringlengths 31 117 | topic stringclasses 4
values | section stringlengths 4 49 ⌀ | sublist stringclasses 9
values |
|---|---|---|---|---|---|---|---|---|
Sugar gliders are seasonally adaptive omnivores with a wide variety of foods in their diet, and mainly forage in the lower layers of the forest canopy. Sugar gliders may obtain up to half their daily water intake through drinking rainwater, with the remainder obtained through water held in its food. In summer they are ... | Sugar glider | Wikipedia | 445 | 42991 | https://en.wikipedia.org/wiki/Sugar%20glider | Biology and health sciences | Diprotodontia | Animals |
The age of sexual maturity in sugar gliders varies slightly between the males and females. Males reach maturity at 4 to 12 months of age, while females require from 8 to 12 months. In the wild, sugar gliders breed once or twice a year depending on the climate and habitat conditions, while they can breed multiple times ... | Sugar glider | Wikipedia | 505 | 42991 | https://en.wikipedia.org/wiki/Sugar%20glider | Biology and health sciences | Diprotodontia | Animals |
Territory and members of the group are marked with saliva and a scent produced by separate glands on the forehead and chest of male gliders. Intruders who lack the appropriate scent marking are expelled violently. Rank is established through scent marking; and fighting does not occur within groups, but does occur when ... | Sugar glider | Wikipedia | 315 | 42991 | https://en.wikipedia.org/wiki/Sugar%20glider | Biology and health sciences | Diprotodontia | Animals |
Conservation
Under the prior taxonomy, the sugar glider was not considered endangered, and its conservation rank was "Least Concern (LC)" on the IUCN Red List. However, with newer taxonomic studies indicating that it has a small and restricted range, it is now thought to be far more sensitive to potential threats. For... | Sugar glider | Wikipedia | 367 | 42991 | https://en.wikipedia.org/wiki/Sugar%20glider | Biology and health sciences | Diprotodontia | Animals |
In captivity, the sugar glider can suffer from calcium deficiencies if not fed an adequate diet. A lack of calcium in the diet causes the body to leach calcium from the bones, with the hind legs first to show noticeable dysfunction. Calcium to phosphorus ratios should be 2:1 to prevent hypocalcemia, sometimes known as ... | Sugar glider | Wikipedia | 455 | 42991 | https://en.wikipedia.org/wiki/Sugar%20glider | Biology and health sciences | Diprotodontia | Animals |
A levee ( or ), dike (American English), dyke (British English; see spelling differences), embankment, floodbank, or stop bank is an elevated ridge, natural or artificial, alongside the banks of a river, often intended to protect against flooding of the area adjoining the river. It is usually earthen and often runs par... | Levee | Wikipedia | 411 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
In Anglo-Saxon, the word already existed and was pronounced as dick in northern England and as ditch in the south. Similar to Dutch, the English origins of the word lie in digging a trench and forming the upcast soil into a bank alongside it. This practice has meant that the name may be given to either the excavation ... | Levee | Wikipedia | 475 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Some of the earliest levees were constructed by the Indus Valley civilization (in Pakistan and North India from ) on which the agrarian life of the Harappan peoples depended. Levees were also constructed over 3,000 years ago in ancient Egypt, where a system of levees was built along the left bank of the River Nile for ... | Levee | Wikipedia | 482 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Artificial levees require substantial engineering. Their surface must be protected from erosion, so they are planted with vegetation such as Bermuda grass in order to bind the earth together. On the land side of high levees, a low terrace of earth known as a banquette is usually added as another anti-erosion measure. O... | Levee | Wikipedia | 462 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
The United States Army Corps of Engineers (USACE) recommends and supports cellular confinement technology (geocells) as a best management practice. Particular attention is given to the matter of surface erosion, overtopping prevention and protection of levee crest and downstream slope. Reinforcement with geocells provi... | Levee | Wikipedia | 496 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
These typically man-made hydraulic structures are situated to protect against erosion. They are typically placed in alluvial rivers perpendicular, or at an angle, to the bank of the channel or the revetment, and are used widely along coastlines. There are two common types of spur dyke, permeable and impermeable, depend... | Levee | Wikipedia | 461 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Both natural and man-made levees can fail in a number of ways. Factors that cause levee failure include overtopping, erosion, structural failures, and levee saturation. The most frequent (and dangerous) is a levee breach. Here, a part of the levee actually breaks or is eroded away, leaving a large opening for water to ... | Levee | Wikipedia | 248 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Among various failure mechanisms that cause levee breaches, soil erosion is found to be one of the most important factors. Predicting soil erosion and scour generation when overtopping happens is important in order to design stable levee and floodwalls. There have been numerous studies to investigate the erodibility of... | Levee | Wikipedia | 464 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Increased height
In a natural watershed, floodwaters spread over a landscape and slowly return to the river. Downstream, the delivery of water from the area of flooding is spread out in time. If levees keep the floodwaters inside a narrow channel, the water is delivered downstream over a shorter time period. The same ... | Levee | Wikipedia | 390 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
Coastal sediment loss
Where a large river spills out into the ocean, the velocity of the water suddenly slows and its ability to transport sand and silt decreases. Sediments begin to settle out, eventually forming a delta and extending to the coastline seaward. During subsequent flood events, water spilling out of the... | Levee | Wikipedia | 193 | 43024 | https://en.wikipedia.org/wiki/Levee | Technology | Hydraulic infrastructure | null |
In computing, endianness is the order in which bytes within a word of digital data are transmitted over a data communication medium or addressed (by rising addresses) in computer memory, counting only byte significance compared to earliness. Endianness is primarily expressed as big-endian (BE) or little-endian (LE), te... | Endianness | Wikipedia | 447 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Big-endianness is the dominant ordering in networking protocols, such as in the Internet protocol suite, where it is referred to as network order, transmitting the most significant byte first. Conversely, little-endianness is the dominant ordering for processor architectures (x86, most ARM implementations, base RISC-V ... | Endianness | Wikipedia | 426 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Positional number systems (mostly base 2, or less often base 10) are the predominant way of representing and particularly of manipulating integer data by computers. In pure form this is valid for moderate sized non-negative integers, e.g. of C data type unsigned. In such a number system, the value of a digit which it c... | Endianness | Wikipedia | 482 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
This behavior arises, for example, in FourCC or similar techniques that involve packing characters into an integer, so that it becomes a sequence of specific characters in memory. For example, take the string "JOHN", stored in hexadecimal ASCII. On big-endian machines, the value appears left-to-right, coinciding with t... | Endianness | Wikipedia | 444 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
On most systems, the address of a multi-byte value is the address of its first byte (the byte with the lowest address); little-endian systems of that type have the property that, for sufficiently low data values, the same value can be read from memory at different lengths without using different addresses (even when al... | Endianness | Wikipedia | 498 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Many historical and extant processors use a big-endian memory representation, either exclusively or as a design option. The IBM System/360 uses big-endian byte order, as do its successors System/370, ESA/390, and z/Architecture. The PDP-10 uses big-endian addressing for byte-oriented instructions. The IBM Series/1 mini... | Endianness | Wikipedia | 402 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Some instruction set architectures feature a setting which allows for switchable endianness in data fetches and stores, instruction fetches, or both; those instruction set architectures are referred to as bi-endian. Architectures that support switchable endianness include PowerPC/Power ISA, SPARC V9, ARM versions 3 and... | Endianness | Wikipedia | 446 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Some nominally bi-endian CPUs require motherboard help to fully switch endianness. For instance, the 32-bit desktop-oriented PowerPC processors in little-endian mode act as little-endian from the point of view of the executing programs, but they require the motherboard to perform a 64-bit swap across all 8 byte lanes t... | Endianness | Wikipedia | 509 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
SPARC historically used big-endian until version 9, which is bi-endian. Similarly early IBM POWER processors were big-endian, but the PowerPC and Power ISA descendants are now bi-endian. The ARM architecture was little-endian before version 3 when it became bi-endian.
Floating point
Although many processors use litt... | Endianness | Wikipedia | 498 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Numerous other orderings, generically called middle-endian or mixed-endian, are possible.
The PDP-11 is in principle a 16-bit little-endian system. The instructions to convert between floating-point and integer values in the optional floating-point processor of the PDP-11/45, PDP-11/70, and in some later processors, s... | Endianness | Wikipedia | 457 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Unicode text can optionally start with a byte order mark (BOM) to signal the endianness of the file or stream. Its code point is U+FEFF. In UTF-32 for example, a big-endian file should start with ; a little-endian should start with .
Application binary data formats, such as MATLAB .mat files, or the .bil data format, ... | Endianness | Wikipedia | 480 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
However, not all protocols use big-endian byte order as the network order. The Server Message Block (SMB) protocol uses little-endian byte order. In CANopen, multi-byte parameters are always sent least significant byte first (little-endian). The same is true for Ethernet Powerlink.
The Berkeley sockets API defines a s... | Endianness | Wikipedia | 195 | 43026 | https://en.wikipedia.org/wiki/Endianness | Technology | Computer architecture concepts | null |
Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads/sidewalks) for travel and transportation.
Traffic laws govern and regulate traffic, while rules of the road include traffic laws and informal rules that may have developed over time to facilita... | Traffic | Wikipedia | 462 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Rules of the road and driving etiquette are the general practices and procedures that road users are required to follow. These rules usually apply to all road users, though they are of special importance to motorists and cyclists. These rules govern interactions between vehicles and pedestrians. The basic traffic rules... | Traffic | Wikipedia | 498 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Vehicles often come into conflict with other vehicles and pedestrians because their intended courses of travel intersect, and thus interfere with each other's routes. The general principle that establishes who has the right to go first is called "right of way" or "priority". It establishes who has the right to use the ... | Traffic | Wikipedia | 476 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Turning
Drivers often seek to turn onto another road or onto private property. The vehicle's blinking turn signals (commonly known as "blinkers" or "indicators") are often used as a way to announce one's intention to turn, thus alerting other drivers. The actual usage of directional signals varies greatly amongst cou... | Traffic | Wikipedia | 389 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
On roads with multiple lanes, turning traffic is generally expected to move to the lane closest to the direction they wish to turn. For example, traffic intending to turn right will usually move to the rightmost lane before the intersection. Likewise, left-turning traffic will move to the leftmost lane. Exceptions to ... | Traffic | Wikipedia | 501 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Other countries use various methods similar to the above examples to establish the right of way at intersections. For example, in most of the United States, the default priority is to yield to traffic from the right, but this is usually overridden by traffic control devices or other rules, like the boulevard rule. Thi... | Traffic | Wikipedia | 442 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
In Europe and other places, there are similar intersections. These may be marked by special signs (according to the Vienna Convention on Road Signs and Signals), a danger sign with a black X representing a crossroads. This sign informs drivers that the intersection is uncontrolled and that default rules apply. In Europ... | Traffic | Wikipedia | 471 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Some pedestrian crossings accompany a traffic signal to make vehicles stop at regular intervals so pedestrians can cross. Some countries have "intelligent" pedestrian signals, where the pedestrian must push a button in order to assert their intention to cross. In some countries, approaching traffic is monitored by ra... | Traffic | Wikipedia | 400 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
To enforce speed limits, two approaches are generally employed. In the United States, it is common for the police to patrol the streets and use special equipment (typically a radar unit) to measure the speed of vehicles, and pull over any vehicle found to be in violation of the speed limit. In Brazil, Colombia and some... | Traffic | Wikipedia | 489 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
On roads that have multiple lanes going in the same direction, drivers may usually shift amongst lanes as they please, but they must do so in a way that does not cause inconvenience to other drivers. Driving cultures vary greatly on the issue of "lane ownership": in some countries, drivers traveling in a lane will be v... | Traffic | Wikipedia | 455 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Many areas in North America do not have any laws about staying to the slowest lanes unless overtaking. In those areas, unlike many parts of Europe, traffic is allowed to overtake on any side, even in a slower lane. This practice is known as "passing on the right" in the United States and "overtaking on the inside" and ... | Traffic | Wikipedia | 483 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
In order to increase traffic capacity and safety, a route may have two or more separate roads for each direction of traffic. Alternatively, a given road might be declared one-way.
High-speed roads
In large cities, moving from one part of the city to another by means of ordinary streets and avenues can be time-consumi... | Traffic | Wikipedia | 452 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
In more sophisticated systems such as large cities, this concept is further extended: some streets are marked as being one-way, and on those streets all traffic must flow in only one direction. Pedestrians on the sidewalks are generally not limited to one-way movement. Drivers wishing to reach a destination they have... | Traffic | Wikipedia | 440 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
In the United States and Canada, several expressways have a special lane (called an "HOV Lane" – High Occupancy Vehicle Lane) that can only be used by cars carrying two (some locations-three) or more people. Also, many major cities have instituted strict parking prohibitions during rush hour on major arterial streets l... | Traffic | Wikipedia | 431 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
During emergencies where evacuation of a heavily populated area is required, local authorities may institute contraflow lane reversal, in which all lanes of a road lead away from a danger zone regardless of their original flow. Aside from emergencies, contraflow may also be used to ease traffic congestion during rush h... | Traffic | Wikipedia | 409 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Aviation
In aviation, right-of-way rules are established over the principle that the least maneuverable aircraft takes priority. In the United States, the Code of Federal Regulations ranks air traffic in the following passage order:
Any aircraft in distress
Air balloon
Glider
Airship
An aircraft towing or refueli... | Traffic | Wikipedia | 132 | 43081 | https://en.wikipedia.org/wiki/Traffic | Technology | Basics_7 | null |
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large biref... | Rutile | Wikipedia | 440 | 43085 | https://en.wikipedia.org/wiki/Rutile | Physical sciences | Minerals | Earth science |
The occurrence of large specimen crystals is most common in pegmatites, skarns, and granite greisens. Rutile is found as an accessory mineral in some altered igneous rocks, and in certain gneisses and schists. In groups of acicular crystals it is frequently seen penetrating quartz as in the from Graubünden, Switzerlan... | Rutile | Wikipedia | 429 | 43085 | https://en.wikipedia.org/wiki/Rutile | Physical sciences | Minerals | Earth science |
Finely powdered rutile is a brilliant white pigment and is used in paints, plastics, paper, foods, and other applications that call for a bright white color. Titanium dioxide pigment is the single greatest use of titanium worldwide. Nanoscale particles of rutile are transparent to visible light but are highly effective... | Rutile | Wikipedia | 426 | 43085 | https://en.wikipedia.org/wiki/Rutile | Physical sciences | Minerals | Earth science |
As the result of growing research interest in the photocatalytic activity of titanium dioxide, in both anatase and rutile phases (as well as biphasic mixtures of the two phases), rutile TiO2 in powder and thin film form is frequently fabricated in laboratory conditions through solution based routes using inorganic prec... | Rutile | Wikipedia | 177 | 43085 | https://en.wikipedia.org/wiki/Rutile | Physical sciences | Minerals | Earth science |
A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores (zoospores), and from a wide range of microorganisms to provide motility. Many protists with flagella are known as flagellates.
A microorganism may have from ... | Flagellum | Wikipedia | 414 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Bacterial flagella are helical filaments, each with a rotary motor at its base which can turn clockwise or counterclockwise. They provide two of several kinds of bacterial motility.
Archaeal flagella (archaella) are superficially similar to bacterial flagella in that it also has a rotary motor, but are different in man... | Flagellum | Wikipedia | 495 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
The basal body has several traits in common with some types of secretory pores, such as the hollow, rod-like "plug" in their centers extending out through the plasma membrane. The similarities between bacterial flagella and bacterial secretory system structures and proteins provide scientific evidence supporting the th... | Flagellum | Wikipedia | 470 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
The production and rotation of a flagellum can take up to 10% of an Escherichia coli cell's energy budget and has been described as an "energy-guzzling machine". Its operation generates reactive oxygen species that elevate mutation rates.
The cylindrical shape of flagella is suited to locomotion of microscopic organ... | Flagellum | Wikipedia | 419 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
At least 10 protein components of the bacterial flagellum share homologous proteins with the type three secretion system (T3SS) found in many gram-negative bacteria, hence one likely evolved from the other. Because the T3SS has a similar number of components as a flagellar apparatus (about 25 proteins), which one evolv... | Flagellum | Wikipedia | 481 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Flagellar arrangements
Different species of bacteria have different numbers and arrangements of flagella, named using the term tricho, from the Greek trichos meaning hair.
Monotrichous bacteria such as Vibrio cholerae have a single polar flagellum.
Amphitrichous bacteria have a single flagellum on each of two opposite ... | Flagellum | Wikipedia | 511 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Bundling
Bundling is an event that can happen in multi-flagellated cells, bundling the flagella together and causing them to rotate in a coordinated manner.
Flagella are left-handed helices, and when rotated counter-clockwise by their rotors, they can bundle and rotate together. When the rotors reverse direction, thu... | Flagellum | Wikipedia | 479 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Internal structure
The core of a eukaryotic flagellum, known as the axoneme is a bundle of nine fused pairs of microtubules known as doublets surrounding two central single microtubules (singlets). This 9+2 axoneme is characteristic of the eukaryotic flagellum. At the base of a eukaryotic flagellum is a basal body, "bl... | Flagellum | Wikipedia | 471 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Although eukaryotic cilia and flagella are ultimately the same, they are sometimes classed by their pattern of movement, a tradition from before their structures have been known. In the case of flagella, the motion is often planar and wave-like, whereas the motile cilia often perform a more complicated three-dimensiona... | Flagellum | Wikipedia | 309 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Flagellated lifecycle stages are found in many groups, e.g., many green algae (zoospores and male gametes), bryophytes (male gametes), pteridophytes (male gametes), some gymnosperms (cycads and Ginkgo, as male gametes), centric diatoms (male gametes), brown algae (zoospores and gametes), oomycetes (assexual zoospores a... | Flagellum | Wikipedia | 320 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Typology
A number of terms related to flagella or cilia are used to characterize eukaryotes. According to surface structures present, flagella may be:
whiplash flagella (= smooth, acronematic flagella): without hairs, e.g., in Opisthokonta
hairy flagella (= tinsel, flimmer, pleuronematic flagella): with hairs (= mastig... | Flagellum | Wikipedia | 374 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
According to the number of flagella, cells may be: (remembering that some authors use "ciliated" instead of "flagellated")
uniflagellated: e.g., most Opisthokonta
biflagellated: e.g., all Dinoflagellata, the gametes of Charophyceae, of most bryophytes and of some metazoans
triflagellated: e.g., the gametes of some Fora... | Flagellum | Wikipedia | 407 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Other terms related to the flagellar type:
isokont: cells with flagella of equal length. It was also formerly used to refer to the Chlorophyta
anisokont: cells with flagella of unequal length, e.g., some Euglenophyceae and Prasinophyceae
heterokont: term introduced by Luther (1899) to refer to the Xanthophyceae, due to... | Flagellum | Wikipedia | 466 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
Bacterial flagella rotation is powered by the proton motive force – a flow of H+ ions or occasionally by the sodium-motive force – a flow of Na+ ions; archaeal flagella rotation is powered by ATP.
While bacterial cells often have many flagellar filaments, each of which rotates independently, the archaeal flagellum is ... | Flagellum | Wikipedia | 484 | 43093 | https://en.wikipedia.org/wiki/Flagellum | Biology and health sciences | Organelles and other cell parts | null |
The cilium (: cilia; ; in Medieval Latin and in anatomy, cilium) is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body. Eukaryotic fla... | Cilium | Wikipedia | 384 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Motile cilia are found in large numbers on respiratory epithelial cells – around 200 cilia per cell, where they function in mucociliary clearance, and also have mechanosensory and chemosensory functions. Motile cilia on ependymal cells move the cerebrospinal fluid through the ventricular system of the brain. Motile cil... | Cilium | Wikipedia | 434 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Transition zone
To achieve its distinct composition, the proximal-most region of the cilium consists of a transition zone, also known as the ciliary gate, that controls the entry and exit of proteins to and from the cilium. At the transition zone, Y-shaped structures connect the ciliary membrane to the underlying axone... | Cilium | Wikipedia | 482 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Non-motile cilia
In animals, non-motile primary cilia are found on nearly every type of cell, blood cells being a prominent exception. Most cells only possess one, in contrast to cells with motile cilia, an exception being olfactory sensory neurons, where the odorant receptors are located, which each possess about ten ... | Cilium | Wikipedia | 509 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Modified non-motile cilia
Kinocilia that are found on hair cells in the inner ear are termed as specialized primary cilia, or modified non-motile cilia. They possess the 9+2 axoneme of the motile cilia but lack the inner dynein arms that give movement. They do move passively following the detection of sound, allowed by... | Cilium | Wikipedia | 438 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Motile, multiple, 9+0 cilia are found on the epithelial cells of the choroid plexus. Cilia also can change structure when introduced to hot temperatures and become sharp. They are present in large numbers on each cell and move relatively slowly, making them intermediate between motile and primary cilia. In addition to ... | Cilium | Wikipedia | 473 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
At the base of the cilium where it attaches to the cell body is the microtubule organizing center, the basal body. Some basal body proteins as CEP164, ODF2
and CEP170, are required for the formation and the stability of the cilium.
In effect, the cilium is a nanomachine composed of perhaps over 600 proteins in molecul... | Cilium | Wikipedia | 474 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Axo-ciliary synapse
With axo-ciliary synapses, there is communication between serotonergic axons and primary cilia of CA1 pyramidal neurons that alters the neuron's epigenetic state in the nucleus – "a way to change what is being transcribed or made in the nucleus" via this signalling distinct from that at the plasma m... | Cilium | Wikipedia | 482 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Since the flagellum of human sperm has the same internal structure of a cilium, ciliary dysfunction can also be responsible for male infertility.
There is an association of primary ciliary dyskinesia with left-right anatomic abnormalities such as situs inversus (a combination of findings is known as Kartagener syndrom... | Cilium | Wikipedia | 495 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Primary cilia in pancreatic cells
The pancreas is a mixture of highly differentiated exocrine and endocrine cells. Primary cilia are present in exocrine cells, which are centroacinar duct cells. Endocrine tissue is composed of different hormone-secreting cells. Insulin-secreting beta cells and glucagon-secreting alpha... | Cilium | Wikipedia | 83 | 43118 | https://en.wikipedia.org/wiki/Cilium | Biology and health sciences | Cell parts | Biology |
Callisto ( ), or Jupiter IV, is the second-largest moon of Jupiter, after Ganymede. In the Solar System it is the third-largest moon after Ganymede and Saturn's largest moon Titan, and nearly as large as the smallest planet Mercury. Callisto is, with a diameter of , roughly a third larger than Earth's Moon and orbits J... | Callisto (moon) | Wikipedia | 422 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
It is not in an orbital resonance like the three other Galilean satellites—Io, Europa and Ganymede—and is thus not appreciably tidally heated. Callisto's rotation is tidally locked to its orbit around Jupiter, so that it always faces the same direction, making Jupiter appear to hang directly overhead over its near-side... | Callisto (moon) | Wikipedia | 510 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
There's no established English adjectival form of the name. The adjectival form of Greek Καλλιστῴ Kallistōi is Καλλιστῴος Kallistōi-os, from which one might expect Latin Callistōius and English *Callistóian (with 5 syllables), parallel to Sapphóian (4 syllables) for Sapphōi and Letóian for Lētōi. However, the iota subs... | Callisto (moon) | Wikipedia | 477 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
The dynamical isolation of Callisto means that it has never been appreciably tidally heated, which has important consequences for its internal structure and evolution. Its distance from Jupiter also means that the charged-particle flux from Jupiter's magnetosphere at its surface is relatively low—about 300 times lower ... | Callisto (moon) | Wikipedia | 491 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
The Callistoan surface is asymmetric: the leading hemisphere is darker than the trailing one. This is different from other Galilean satellites, where the reverse is true. The trailing hemisphere of Callisto appears to be enriched in carbon dioxide, whereas the leading hemisphere has more sulfur dioxide. Many fresh impa... | Callisto (moon) | Wikipedia | 485 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
However, a 2011 reanalysis of Galileo data suggests that Callisto is not in hydrostatic equilibrium. In that case, the gravity data may be more consistent with a more thoroughly differentiated Callisto with a hydrated silicate core.
Surface features
The ancient surface of Callisto is one of the most heavily cratered ... | Callisto (moon) | Wikipedia | 435 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
Impact crater diameters seen range from 0.1 km—a limit defined by the imaging resolution—to over 100 km, not counting the multi-ring structures. Small craters, with diameters less than 5 km, have simple bowl or flat-floored shapes. Those 5–40 km across usually have a central peak. Larger impact features, with diameters... | Callisto (moon) | Wikipedia | 500 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
On a sub-kilometer scale the surface of Callisto is more degraded than the surfaces of other icy Galilean moons. Typically there is a deficit of small impact craters with diameters less than 1 km as compared with, for instance, the dark plains on Ganymede. Instead of small craters, the almost ubiquitous surface feature... | Callisto (moon) | Wikipedia | 510 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
Callisto's ionosphere was first detected during Galileo flybys; its high electron density of 7–17 cm−3 cannot be explained by the photoionization of the atmospheric carbon dioxide alone. Hence, it is suspected that the atmosphere of Callisto is actually dominated by molecular oxygen (in amounts 10–100 times greater tha... | Callisto (moon) | Wikipedia | 427 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
The further evolution of Callisto after accretion was determined by the balance of the radioactive heating, cooling through thermal conduction near the surface, and solid state or subsolidus convection in the interior. Details of the subsolidus convection in the ice is the main source of uncertainty in the models of al... | Callisto (moon) | Wikipedia | 494 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
Although Callisto is very similar in bulk properties to Ganymede, it apparently had a much simpler geological history. The surface appears to have been shaped mainly by impacts and other exogenic forces. Unlike neighboring Ganymede with its grooved terrain, there is little evidence of tectonic activity. Explanations th... | Callisto (moon) | Wikipedia | 363 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
Past
The Pioneer 10 and Pioneer 11 Jupiter encounters in the early 1970s contributed little new information about Callisto in comparison with what was already known from Earth-based observations. The real breakthrough happened later with the Voyager 1 and Voyager 2 flybys in 1979. They imaged more than half of the Call... | Callisto (moon) | Wikipedia | 475 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
The study proposed a possible surface base on Callisto that would produce rocket propellant for further exploration of the Solar System. Advantages of a base on Callisto include low radiation (due to its distance from Jupiter) and geological stability. Such a base could facilitate remote exploration of Europa, or be an... | Callisto (moon) | Wikipedia | 116 | 43126 | https://en.wikipedia.org/wiki/Callisto%20%28moon%29 | Physical sciences | Solar System | null |
Europa , or Jupiter II, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 95 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Europa was discovered independently by Simon Marius and Galileo Galilei and was named (by Marius) after Eu... | Europa (moon) | Wikipedia | 500 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The Galileo mission, launched in 1989, provides the bulk of current data on Europa. No spacecraft has yet landed on Europa, although there have been several proposed exploration missions. The European Space Agency's Jupiter Icy Moon Explorer (JUICE) is a mission to Ganymede launched on 14 April 2023, that will include ... | Europa (moon) | Wikipedia | 403 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Europa orbits Jupiter in just over three and a half days, with an orbital radius of about 670,900 km. With an orbital eccentricity of only 0.009, the orbit itself is nearly circular, and the orbital inclination relative to Jupiter's equatorial plane is small, at 0.470°. Like its fellow Galilean satellites, Europa is ti... | Europa (moon) | Wikipedia | 387 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Analysis of the unique cracks lining Europa yielded evidence that it likely spun around a tilted axis at some point in time. If correct, this would explain many of Europa's features. Europa's immense network of crisscrossing cracks serves as a record of the stresses caused by massive tides in its global ocean. Europa's... | Europa (moon) | Wikipedia | 495 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Europa is the smoothest known object in the Solar System, lacking large-scale features such as mountains and craters. The prominent markings crisscrossing Europa appear to be mainly albedo features that emphasize low topography. There are few craters on Europa, because its surface is tectonically too active and therefo... | Europa (moon) | Wikipedia | 363 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The most likely hypothesis is that the lineae on Europa were produced by a series of eruptions of warm ice as Europa's crust slowly spreads open to expose warmer layers beneath. The effect would have been similar to that seen on Earth's oceanic ridges. These various fractures are thought to have been caused in large pa... | Europa (moon) | Wikipedia | 439 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
One hypothesis states that these lenticulae were formed by diapirs of warm ice rising up through the colder ice of the outer crust, much like magma chambers in Earth's crust. The smooth, dark spots could be formed by meltwater released when the warm ice breaks through the surface. The rough, jumbled lenticulae (called ... | Europa (moon) | Wikipedia | 343 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The scientific consensus is that a layer of liquid water exists beneath Europa's surface, and that heat from tidal flexing allows the subsurface ocean to remain liquid. Europa's surface temperature averages about at the equator and only at the poles, keeping Europa's icy crust as hard as granite. The first hints of a... | Europa (moon) | Wikipedia | 495 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The Galileo orbiter found that Europa has a weak magnetic moment, which is induced by the varying part of the Jovian magnetic field. The field strength at the magnetic equator (about 120 nT) created by this magnetic moment is about one-sixth the strength of Ganymede's field and six times the value of Callisto's. The ex... | Europa (moon) | Wikipedia | 493 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Europa receives thermal energy from tidal heating, which occurs through the tidal friction and tidal flexing processes caused by tidal acceleration: orbital and rotational energy are dissipated as heat in the core of the moon, the internal ocean, and the ice crust.
Tidal friction
Ocean tides are converted to heat by f... | Europa (moon) | Wikipedia | 473 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The Hubble Space Telescope acquired an image of Europa in 2012 that was interpreted to be a plume of water vapour erupting from near its south pole. The image suggests the plume may be high, or more than 20 times the height of Mt. Everest., though recent observations and modeling suggest that typical Europan plumes ma... | Europa (moon) | Wikipedia | 321 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
In November 2020, a study was published in the peer-reviewed scientific journal Geophysical Research Letters suggesting that the plumes may originate from water within the crust of Europa as opposed to its subsurface ocean. The study's model, using images from the Galileo space probe, proposed that a combination of fre... | Europa (moon) | Wikipedia | 232 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
The atmosphere of Europa can be categorized as thin and tenuous (often called an exosphere), primarily composed of oxygen and trace amounts of water vapor. However, this quantity of oxygen is produced in a non-biological manner. Given that Europa's surface is icy, and subsequently very cold; as solar ultraviolet radiat... | Europa (moon) | Wikipedia | 502 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
5 Gyr maximum age of Europa's surface ice, subduction of radiolytically generated oxidizing species might well lead to oceanic free oxygen concentrations that are comparable to those in terrestrial deep oceans | Europa (moon) | Wikipedia | 40 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Through the slow release of oxygen and hydrogen, a neutral torus around Europa's orbital plane is formed. This "neutral cloud" has been detected by both the Cassini and Galileo spacecraft, and has a greater content (number of atoms and molecules) than the neutral cloud surrounding Jupiter's inner moon Io. This torus wa... | Europa (moon) | Wikipedia | 321 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Climate and weather
Despite the presence of a gas torus, Europa has no weather producing clouds. As a whole, Europa has no wind, precipitation, or presence of sky color as its gravity is too low to hold an atmosphere substantial enough for those features. Europa's gravity is approximately 13% of Earth's. The temperatu... | Europa (moon) | Wikipedia | 462 | 43127 | https://en.wikipedia.org/wiki/Europa%20%28moon%29 | Physical sciences | Solar System | null |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.