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The first generation of iPad Air was announced on October 22, 2013, and released on November 1. It used an Apple A7 chip with an embedded Apple M7 Motion coprocessor; the chip included over a billion transistors and comprised a 2× faster CPU and GPU. It debuted the 802.11n-based MINO technology used in its Wi-Fi connec... | IPad | Wikipedia | 463 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The sixth generation of iPad Air was announced on May 7, 2024, with the general availability on May 15, 2024. It used an Apple M2 chip. It is the first iPad Air to have the available two display size options including 11-inch and 13-inch. It features the Apple Pencil hover which is previously featured on the iPad Pro (... | IPad | Wikipedia | 425 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The third generation of iPad Pro was announced on October 30, 2018, and released on November 7, and it is the first iPad to support 1TB of storage. It used a 7 nm Apple A12X Bionic chip, which comprised 11 billion transistors, an 8-core CPU, 7-core GPU and an embedded Neural Engine capable of processing 5 trillion oper... | IPad | Wikipedia | 442 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The seventh generation of iPad Pro was announced on May 7, 2024, a release on May 15, 2024. It uses an Apple M4, making it the first Apple device to use this chip. It is the first iPad Pro to use OLED display, called Ultra XDR Retina Display. The chassis design is about 5.3mm thin on the 11-inch model and 5.1mm thin on... | IPad | Wikipedia | 445 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
Apple extended the range of cellular compatibilities worldwide with the release of the fifth generation of iPad and the second generation of iPad Mini, worldwide and all major carriers across North America. The iPad Air and iPad Mini come in two cellular sub-variants, all of which featured nano-SIMs, quad-band GSM, pen... | IPad | Wikipedia | 456 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The iOS user interface is based upon direct manipulation, using multi-touch gestures such as swipe, tap, pinch, and reverse pinch. Interface control elements include sliders, switches, and buttons. Internal accelerometers are used by some applications to respond to shaking the device (one common result is the undo comm... | IPad | Wikipedia | 409 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
iOS' multitasking API included Background audio – application continues to run in the background as long as it is playing audio or video content, voice over IP – application is suspended when a phone call is not in progress, Push notification, Local notifications – application schedules local notifications to be delive... | IPad | Wikipedia | 269 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
In iPadOS, while using an app, swiping up slightly from the bottom edge of the screen will summon the Dock, where apps stored within can be dragged to different areas of the current space to be opened in either Split View or Slide Over. Dragging an app to the left or right edge of the screen will create a Split View, w... | IPad | Wikipedia | 503 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
Like other iOS devices, the iPad can be "jailbroken", depending on which version of iOS or iPadOS it is running, thus allowing applications and programs that are not authorized by Apple to run on the device. Once it is jailbroken, users are able to download many applications previously unavailable through the App Store... | IPad | Wikipedia | 485 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
Reaction to the announcement
Media reaction to the announcement of the original iPad was mixed. Walter Mossberg wrote, "It's about the software, stupid", meaning hardware features and build are less important to the iPad's success than software and user interface, his first impressions of which were largely positive. ... | IPad | Wikipedia | 447 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The media also praised the quantity of applications, as well as the bookstore and other media applications. In contrast they criticized the iPad for being a closed system and mentioned that the iPad faces competition from Android-based tablets, that outsold iPads in 2013, surpassing iPads in the second quarter of 2013,... | IPad | Wikipedia | 425 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
Since March 2011, the US Federal Aviation Administration (FAA) has approved the iPad for in-cockpit use to cut down on the paper consumption in several airlines. In 2011, Alaska Airlines became the first airline to replace pilots' paper manuals with iPads, weighing compared to for the printed flight manuals. It hopes... | IPad | Wikipedia | 495 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The iPad is able to support many music creation applications in addition to the iTunes music playback software. These include sound samplers, guitar and voice effects processors, sequencers for synthesized sounds and sampled loops, virtual synthesizers and drum machines, theremin-style and other touch responsive instru... | IPad | Wikipedia | 134 | 25970423 | https://en.wikipedia.org/wiki/IPad | Technology | Specific hardware | null |
The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ophis meaning "snake", and refers to their eel-like appearance. True eels diverged from other ray-finned fish during the Jurassic, while cusk-eels are part of the Percomorpha clade, along ... | Cusk-eel | Wikipedia | 409 | 3910825 | https://en.wikipedia.org/wiki/Cusk-eel | Biology and health sciences | Acanthomorpha | Animals |
Characteristics
Cusk-eels are characterized by a long, slender body that is about 12–13 times as long as it is deep. The largest species, Lamprogrammus shcherbachevi, grows up to in length, but most species are shorter than . Their dorsal and anal fins are typically continuous with the caudal fin (with exception to a... | Cusk-eel | Wikipedia | 511 | 3910825 | https://en.wikipedia.org/wiki/Cusk-eel | Biology and health sciences | Acanthomorpha | Animals |
Genus †Ampheristus (extinct)
Subfamily Brotulinae
Genus Brotula – typical brotulas
Subfamily Brotulotaenilinae
Genus Brotulotaenia
Subfamily Neobythitinae
Genus Abyssobrotula
Genus Acanthonus – boney-eared assfish
Genus Alcockia
Genus Apagesoma
Genus Barathrites
Genus Barathrodemus
Genus Bassogigas
Genus Ba... | Cusk-eel | Wikipedia | 361 | 3910825 | https://en.wikipedia.org/wiki/Cusk-eel | Biology and health sciences | Acanthomorpha | Animals |
In mathematics, a multiple is the product of any quantity and an integer. In other words, for the quantities a and b, it can be said that b is a multiple of a if b = na for some integer n, which is called the multiplier. If a is not zero, this is equivalent to saying that is an integer.
When a and b are both integers... | Multiple (mathematics) | Wikipedia | 345 | 3912709 | https://en.wikipedia.org/wiki/Multiple%20%28mathematics%29 | Mathematics | Basics | null |
Submultiple
In some texts, "a is a submultiple of b" has the meaning of "a being a unit fraction of b" (ab/n) or, equivalently, "b being an integer multiple n of a" (bna). This terminology is also used with units of measurement (for example by the BIPM and NIST), where a unit submultiple is obtained by prefixing the ma... | Multiple (mathematics) | Wikipedia | 175 | 3912709 | https://en.wikipedia.org/wiki/Multiple%20%28mathematics%29 | Mathematics | Basics | null |
Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of Streptomyces bacteria or produced semi-synthetically from those isolated compounds. Tetracycline molecules comprise a linear fused tetracyclic nucleus (rings desig... | Tetracycline antibiotics | Wikipedia | 507 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Tetracyclines all have the same antibacterial spectrum, although there are differences in species' sensitivity to types of tetracyclines. Tetracyclines inhibit protein synthesis in both bacterial and human cells. Bacteria have a system that allows tetracyclines to be transported into the cell, whereas human cells do no... | Tetracycline antibiotics | Wikipedia | 290 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Medical uses
Tetracyclines are generally used in the treatment of infections of the urinary tract, respiratory tract, and the intestines and are also used in the treatment of chlamydia, especially in patients allergic to β-lactams and macrolides; however, their use for these indications is less popular than it once was... | Tetracycline antibiotics | Wikipedia | 341 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Side effects
Side-effects from tetracyclines are not common, but of particular note is phototoxicity. It increases the risk of sunburn under exposure to light from the sun or other sources. This may be of particular importance for those intending to take on vacations long-term doxycycline as a malaria prophylaxis.
They... | Tetracycline antibiotics | Wikipedia | 231 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Cautions
Tetracyclines should be used with caution by those with liver impairment. Also, because the molecules are soluble in water it can worsen kidney failure (this is not true of the lipid-soluble agents doxycycline and minocycline). They may increase muscle weakness in myasthenia gravis and exacerbate systemic lupu... | Tetracycline antibiotics | Wikipedia | 411 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Mechanism of action
Tetracycline antibiotics are protein synthesis inhibitors. They inhibit the initiation of translation in variety of ways by binding to the 30S ribosomal subunit, which is made up of 16S rRNA and 21 proteins. They inhibit the binding of aminoacyl-tRNA to the mRNA translation complex. Some studies hav... | Tetracycline antibiotics | Wikipedia | 315 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Tetracyclines are composed of a rigid skeleton of 4 fused rings. The rings structure of tetracyclines is divided into an upper modifiable region and a lower non modifiable region. An active tetracycline requires a C10 phenol as well as a C11-C12 keto-enol substructure in conjugation with a 12a-OH group and a C1-C3 dike... | Tetracycline antibiotics | Wikipedia | 491 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
In ribosomal protection, a resistance gene encodes a protein that can have several effects, depending on what gene is transferred. Twelve classes of ribosomal protection genes/proteins have been found.
Possible mechanisms of action of these protective proteins include:
blocking tetracyclines from binding to the ribos... | Tetracycline antibiotics | Wikipedia | 316 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
History
The history of the tetracyclines involves the collective contributions of thousands of dedicated researchers, scientists, clinicians, and business executives. Tetracyclines were discovered in the 1940s, first reported in scientific literature in 1948, and exhibited activity against a wide range of microorganism... | Tetracycline antibiotics | Wikipedia | 510 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Other tetracyclines were identified later, either as naturally occurring molecules, e.g., tetracycline from S. aureofaciens, S. rimosus, and S. viridofaciens and dimethyl-chlortetracycline from S. aureofaciens, or as products of semisynthetic approaches, e.g., methacycline, doxycycline, and minocycline. | Tetracycline antibiotics | Wikipedia | 104 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Research conducted by anthropologist George J. Armelagos and his team at Emory University showed that ancient Nubians from the post-Meroitic period (around AD 350) had deposits of tetracycline in their bones, detectable through analyses of cross-sections through ultraviolet light – the deposits are fluorescent, just as... | Tetracycline antibiotics | Wikipedia | 255 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Glycylcyclines and fluorocyclines are new classes of antibiotics derived from tetracycline. These tetracycline analogues are specifically designed to overcome two common mechanisms of tetracycline resistance, namely resistance mediated by acquired efflux pumps and/or ribosomal protection.
In 2005, tigecycline, the firs... | Tetracycline antibiotics | Wikipedia | 328 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
Use as research reagents
Members of the tetracycline class of antibiotics are often used as research reagents in in vitro and in vivo biomedical research experiments involving bacteria as well in experiments in eukaryotic cells and organisms with inducible protein expression systems using tetracycline-controlled transc... | Tetracycline antibiotics | Wikipedia | 254 | 3917234 | https://en.wikipedia.org/wiki/Tetracycline%20antibiotics | Biology and health sciences | Antibiotics | Health |
The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus. Rutherford directed the Geiger–Marsden experiment in 1909, which showed much more alpha particle recoil than J. J. Thomson's plum pudding model of the atom could expla... | Rutherford model | Wikipedia | 472 | 3917813 | https://en.wikipedia.org/wiki/Rutherford%20model | Physical sciences | Atomic physics | Physics |
A somewhat similar model proposed by Hantaro Nagaoka in 1904 used Saturn's rings as an analog. The rings consisted of a large number of particles that repelled each other but were attracted to a large central charge. This charge was calculated to be 10,000 times the charge of the ring particles for stability. George A... | Rutherford model | Wikipedia | 442 | 3917813 | https://en.wikipedia.org/wiki/Rutherford%20model | Physical sciences | Atomic physics | Physics |
The Rutherford model served to concentrate a great deal of the atom's charge and mass to a very small core, but did not attribute any structure to the remaining electrons and remaining atomic mass. It did mention the atomic model of Hantaro Nagaoka, in which the electrons are arranged in one or more rings, with the spe... | Rutherford model | Wikipedia | 324 | 3917813 | https://en.wikipedia.org/wiki/Rutherford%20model | Physical sciences | Atomic physics | Physics |
These are the key indicators:
The atom's electron cloud does not (substantially) influence alpha particle scattering.
Much of an atom's positive charge is concentrated in a relatively tiny volume at the center of the atom, known today as the nucleus. The magnitude of this charge is proportional to (up to a charge num... | Rutherford model | Wikipedia | 461 | 3917813 | https://en.wikipedia.org/wiki/Rutherford%20model | Physical sciences | Atomic physics | Physics |
A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital representation. A color space may be arbitrary, i.e. with physically realized colors ... | Color space | Wikipedia | 433 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
History
In 1802, Thomas Young postulated the existence of three types of photoreceptors (now known as cone cells) in the eye, each of which was sensitive to a particular range of visible light. Hermann von Helmholtz developed the Young–Helmholtz theory further in 1850: that the three types of cone photoreceptors could... | Color space | Wikipedia | 505 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
Many color spaces can be represented as three-dimensional values in this manner, but some have more, or fewer dimensions, and some, such as Pantone, cannot be represented in this way at all.
Conversion
Color space conversion is the translation of the representation of a color from one basis to another. This typically... | Color space | Wikipedia | 466 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
CMYK uses subtractive color mixing used in the printing process, because it describes what kind of inks need to be applied so the light reflected from the substrate and through the inks produces a given color. One starts with a white substrate (canvas, page, etc.), and uses ink to subtract color from white to create an... | Color space | Wikipedia | 462 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
HSL (hue, saturation, lightness/luminance), also known as HLS or HSI (hue, saturation, intensity) is quite similar to HSV, with "lightness" replacing "brightness". The difference is that the brightness of a pure color is equal to the brightness of white, while the lightness of a pure color is equal to the lightness of ... | Color space | Wikipedia | 457 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
A popular way to make a color space like RGB into an absolute color is to define an ICC profile, which contains the attributes of the RGB. This is not the only way to express an absolute color, but it is the standard in many industries. RGB colors defined by widely accepted profiles include sRGB and Adobe RGB. The proc... | Color space | Wikipedia | 422 | 21578485 | https://en.wikipedia.org/wiki/Color%20space | Physical sciences | Basics | Physics |
In human anatomy, the mouth is the first portion of the alimentary canal that receives food and produces saliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth.
In addition to its primary role as the beginning of the digestive system, the mouth also plays a significant role in communi... | Human mouth | Wikipedia | 486 | 35869003 | https://en.wikipedia.org/wiki/Human%20mouth | Biology and health sciences | Human anatomy | Health |
Nerve supply
The teeth and the periodontium (the tissues that support the teeth) are innervated by the maxillary and mandibular nerves – divisions of the trigeminal nerve. Maxillary (upper) teeth and their associated periodontal ligament are innervated by the superior alveolar nerves, branches of the maxillary division... | Human mouth | Wikipedia | 500 | 35869003 | https://en.wikipedia.org/wiki/Human%20mouth | Biology and health sciences | Human anatomy | Health |
The nasolabial folds are the deep creases of tissue that extend from the nose to the sides of the mouth. One of the first signs of age on the human face is the increase in prominence of the nasolabial folds.
Function
The mouth plays an important role in eating, drinking, and speaking. Mouth breathing refers to the ac... | Human mouth | Wikipedia | 274 | 35869003 | https://en.wikipedia.org/wiki/Human%20mouth | Biology and health sciences | Human anatomy | Health |
In physics, a force field is a vector field corresponding with a non-contact force acting on a particle at various positions in space. Specifically, a force field is a vector field , where is the force that a particle would feel if it were at the position .
Examples
Gravity is the force of attraction between two obje... | Force field (physics) | Wikipedia | 381 | 2916607 | https://en.wikipedia.org/wiki/Force%20field%20%28physics%29 | Physical sciences | Classical mechanics | Physics |
Sodium sulfide is a chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly s... | Sodium sulfide | Wikipedia | 408 | 2916631 | https://en.wikipedia.org/wiki/Sodium%20sulfide | Physical sciences | Sulfide salts | Chemistry |
Reactions with inorganic reagents
The sulfide ion in sulfide salts such as sodium sulfide can incorporate a proton into the salt by protonation:
+ →
Because of this capture of the proton (), sodium sulfide has basic character. Sodium sulfide is strongly basic, able to absorb two protons. Its conjugate acid is sodiu... | Sodium sulfide | Wikipedia | 430 | 2916631 | https://en.wikipedia.org/wiki/Sodium%20sulfide | Physical sciences | Sulfide salts | Chemistry |
Installation of carbon-sulfur bonds
Alkylation of sodium sulfide give thioethers:
Na2S + 2 RX → R2S + 2 NaX
Even aryl halides participate in this reaction. By a broadly similar process sodium sulfide can react with alkenes in the thiol-ene reaction to give thioethers.
Sodium sulfide can be used as nucleophile... | Sodium sulfide | Wikipedia | 249 | 2916631 | https://en.wikipedia.org/wiki/Sodium%20sulfide | Physical sciences | Sulfide salts | Chemistry |
Rabbitfishes or spinefoots, genus Siganus, are perciform fishes in the family Siganidae. It is the only extant genus in its family and has 29 species. In some now obsolete classifications, the species having prominent face stripes—colloquially called foxfaces–are in the genus Lo. Other species, such as the masked spin... | Rabbitfish | Wikipedia | 465 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
In 2007 Kurriwa et al., outlined a way to split the genus—if the scientific community so desires:
An ancient group containing e.g. S. woodlandi
Another fairly small group containing, e.g., the S. canaliculatus/S. fuscescens) complex
The remainder of Siganus, including the foxfaces
Other lineages might exist and mak... | Rabbitfish | Wikipedia | 346 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
Species
As noted above, several presumed species are suspected to actively interbreed even today; these might warrant merging as a single species. This applies to the white-spotted spinefoot (S. canaliculatus) and the mottled spinefoot (S. fuscescens), and to the blotched foxface (S. unimaculatus) and the foxface rabbi... | Rabbitfish | Wikipedia | 183 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
There are currently 29 recognized species in this genus:
Siganus argenteus (Quoy & Gaimard, 1825) (Streamlined spinefoot)
Siganus canaliculatus (M. Park, 1797) (White-spotted spinefoot)
Siganus corallinus (Valenciennes, 1835) (Blue-spotted spinefoot)
Siganus doliatus Guérin-Méneville, 1829 (Barred spinefoot)
Sig... | Rabbitfish | Wikipedia | 492 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
Siganus vermiculatus (Valenciennes, 1835) (Vermiculated spinefoot)
Siganus virgatus (Valenciennes, 1835) (Barhead spinefoot)
Siganus vulpinus (Schlegel & J. P. Müller, 1845) (Foxface)
Siganus woodlandi Randall & Kulbicki, 2005 | Rabbitfish | Wikipedia | 80 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
Characteristics
Rabbitfishes have laterally compressed, oval bodies which may be deep, or slender. A few species have a tubular snout. The mouth is very small and is with non protractile jaws which have one row of compressed, closely set, incisor-like teeth in each jaw. The teeth overlap slightly and create a beak like... | Rabbitfish | Wikipedia | 375 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
Biology
All rabbitfish are diurnal; some live in schools, while others live more solitary lives among the corals. Rabbitfish sleep in crevices in the reef matrix at night. While sleeping, the rabbitfish Siganus canaliculatus was observed being cleaned by the cleaner shrimp Urocaridella antonbruunii. They are herbivorou... | Rabbitfish | Wikipedia | 320 | 2918131 | https://en.wikipedia.org/wiki/Rabbitfish | Biology and health sciences | Acanthomorpha | Animals |
In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is th... | Stele (biology) | Wikipedia | 273 | 949263 | https://en.wikipedia.org/wiki/Stele%20%28biology%29 | Biology and health sciences | Plant stem | Biology |
There are usually three basic types of protostele:
haplostele – consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis generally surrounds the stele. A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhyn... | Stele (biology) | Wikipedia | 398 | 949263 | https://en.wikipedia.org/wiki/Stele%20%28biology%29 | Biology and health sciences | Plant stem | Biology |
An amphiphloic siphonostele can be called a solenostele, or this term may be used to refer to cases where the cylinder of vascular tissue contains no more than one leaf gap in any transverse section (i.e. has non-overlapping leaf gaps). This type of stele is primarily found in fern stems today. Where there are large ov... | Stele (biology) | Wikipedia | 367 | 949263 | https://en.wikipedia.org/wiki/Stele%20%28biology%29 | Biology and health sciences | Plant stem | Biology |
Placoderms (from Greek πλάξ (plax, plakos) 'plate' and δέρμα (derma) 'skin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian periods. While their endoskeletons are mainly cartilaginous, their head and thorax were cove... | Placoderm | Wikipedia | 455 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Characteristics
Many placoderms, particularly the Rhenanida, Petalichthyida, Phyllolepida, and Antiarchi, were bottom-dwellers. In particular, the antiarchs, with their highly modified, jointed bony pectoral fins, were highly successful inhabitants of Middle-Late Devonian freshwater and shallow marine habitats, with th... | Placoderm | Wikipedia | 473 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Extraordinary evidence of internal fertilization in a placoderm was afforded by the discovery in the Gogo Formation, near Fitzroy Crossing, Kimberley, Western Australia, of a small female placoderm, about in length, which died in the process of giving birth to a 6 cm ( in) offspring and was fossilized with the umbilic... | Placoderm | Wikipedia | 474 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
It was thought for a time that placoderms became extinct due to competition from the first bony fish and early sharks, given a combination of the supposed inherent superiority of bony fish and the presumed sluggishness of placoderms. With more accurate summaries of prehistoric organisms, it is now thought that they sys... | Placoderm | Wikipedia | 451 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
The first officially described Silurian placoderm is an antiarch, Shimenolepis, which is known from distinctively ornamented plates from Hunan, China. It was originally considered to be from the late Llandovery, although later study reconsidered its age at Ludfordian. Shimenolepis plates are very similar to the early D... | Placoderm | Wikipedia | 370 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
In the late 1920s, Dr. Erik Stensiö, at the Swedish Museum of Natural History in Stockholm, established the details of placoderm anatomy and identified them as true jawed fishes related to sharks. He took fossil specimens with well-preserved skulls and ground them away, one tenth of a millimeter at a time. After each l... | Placoderm | Wikipedia | 435 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Arthrodira ("jointed neck") were the most diverse and numerically successful of the placoderm orders, occupying roles from giant apex predators to detritus-nibbling bottom dwellers. They had a movable joint between armour surrounding the head and body. As the lower jaw moved down, the head shield moved, allowing for a ... | Placoderm | Wikipedia | 264 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Antiarchi ("opposite anus") were the second most successful order of placoderms known, after the Arthrodira. The order's name was coined by Edward Drinker Cope, who, after incorrectly identifying the first fossils as being those of an armored tunicate, mistakenly thought the eye-hole was the mouth, and the opening for ... | Placoderm | Wikipedia | 404 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Phyllolepida ("leaf scales") were flattened placoderms found throughout the world. Like other flattened placoderms they were bottom-dwelling predators that ambushed prey. Unlike other flattened placoderms, they were freshwater fish. Their armour was made of whole plates, rather than the numerous tubercles and scales of... | Placoderm | Wikipedia | 483 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Rhenanida ("Rhine fish") were flattened, ray-like, bottom-dwelling predators with large, upturned mouths that lived in marine environments. The rhenanids were once presumed to be the most primitive, or at least the closest to the ancestral placoderm, as their armour was made of unfused components—a mosaic of tubercles—... | Placoderm | Wikipedia | 435 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Petalichthyida ("thin-plated fish") were small, flattened placoderms, typified by their splayed fins and numerous tubercles that decorated all of the plates and scales of their armour. They reached a peak in diversity during the Early Devonian and were found throughout the world. The petalichthids Lunaspis and Wijdeasp... | Placoderm | Wikipedia | 445 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
Stensioellida ("[Heintz's] little Stensio") contains another problematic placoderm of uncertain affinity, known only from the Lower Devonian Hunsrück slates of Germany. Stensioella was a thin fish that, when alive, looked vaguely like an elongated ratfish, or a skinny Gemuendina with thin, strap-like pectoral fins. Sim... | Placoderm | Wikipedia | 383 | 949620 | https://en.wikipedia.org/wiki/Placoderm | Biology and health sciences | Fishes | null |
The little finger or pinkie, also known as the baby finger, fifth digit, or pinky finger, is the most ulnar and smallest digit of the human hand, and next to the ring finger.
Etymology
The word "pinkie" is derived from the Dutch word pink, meaning "little finger".
The earliest recorded use of the term "pinkie" is fro... | Little finger | Wikipedia | 434 | 950991 | https://en.wikipedia.org/wiki/Little%20finger | Biology and health sciences | Human anatomy | Health |
It is a common joke that one should extend their little finger when drinking from a teacup in imitation of a passé upper-class tradition. This practice is generally deprecated by etiquette guides as a sign of snobbery amongst the socially inferior, with various cultural theories as to the origin of the practice includi... | Little finger | Wikipedia | 436 | 950991 | https://en.wikipedia.org/wiki/Little%20finger | Biology and health sciences | Human anatomy | Health |
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's pitch, and therefore the angle of attack and the lift of the wing. The elevators are usually hinged to the tailplane or horizontal stabilizer. They may be the only pitch control surface present, and are sometimes lo... | Elevator (aeronautics) | Wikipedia | 427 | 950992 | https://en.wikipedia.org/wiki/Elevator%20%28aeronautics%29 | Technology | Aircraft components | null |
Elevators' location
Elevators are usually part of the tail, at the rear of an aircraft. In some aircraft, pitch-control surfaces are in the front, ahead of the wing. In a two-surface aircraft this type of configuration is called a canard (the French word for duck) or a tandem wing. The Wright Brothers' early aircraft ... | Elevator (aeronautics) | Wikipedia | 393 | 950992 | https://en.wikipedia.org/wiki/Elevator%20%28aeronautics%29 | Technology | Aircraft components | null |
Bed bugs are parasitic insects from the genus Cimex, who are micropredators that feed on blood, usually at night. Their bites can result in a number of health impacts, including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ranging from small areas of redness to promi... | Bed bug | Wikipedia | 491 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Bites
The most common skin findings associated with bed bug bites are itching, flat and bumpy, reddish lesions. Each lesion is about but may be as large as in diameter and there may or may not be a central spot (punctum). Bites are usually present on areas of exposed skin, especially exposed areas not covered by shee... | Bed bug | Wikipedia | 509 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Serious infestations and chronic attacks can cause anxiety, stress, and sleep difficulties. Development of refractory delusional parasitosis is possible, as a person develops an overwhelming obsession with bed bugs.
Description
Bed bug infestations are primarily the result of two species of insects from genus Cimex: ... | Bed bug | Wikipedia | 439 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Bed bugs are attracted to their hosts primarily by carbon dioxide, secondarily by warmth, and also by certain chemicals. There is strong evidence that bed bugs can respond and orient towards human odors, independently of all other host cues. Cimex lectularius feeds only every five to seven days, which suggests that it ... | Bed bug | Wikipedia | 470 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Bed bugs can occur singly, but tend to congregate once established. Although strictly parasitic, they spend only a tiny fraction of their lives physically attached to hosts. Once a bed bug finishes feeding, it follows a chemical trail to return to a nearby harborage, commonly in or near beds or couches, where they live... | Bed bug | Wikipedia | 333 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Prevention
To prevent bringing home bed bugs from outside the home, people are advised to take precautions after visiting an infested site or traveling on means of transport that may be infested; precautions include checking shoes on leaving the site, changing clothes outside the house before entering, and putting the... | Bed bug | Wikipedia | 480 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Insecticides are mostly ineffective for the eradication of bedbug infestations as most bedbugs are resistant to insecticides, including pyrethroids which are found in approximately 90% of commercial grade insecticides. Furthermore, insect foggers (known as "bug bombs") are ineffective in the eradication of bed bug infe... | Bed bug | Wikipedia | 471 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Bed bugs are found everywhere in the world. Before the 1950s about 30% of houses in the United States had bedbugs; this percentage has fallen, which is believed to be partly due to the use of DDT to kill cockroaches. The invention of the vacuum cleaner and simplification of furniture design may have also played a role ... | Bed bug | Wikipedia | 394 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Species
The common bed bug (Cimex lectularius) is the species best adapted to human environments but is also known from birds, Chiroptera, Gallus (chickens and relatives), Myotis myotis, and sheep (Ovis aries). It is found in temperate climates throughout the world. Other species include C. hemipterus, found in tropica... | Bed bug | Wikipedia | 458 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Traditional methods of repelling or killing bed bugs include the use of plants, fungi, and insects (or their extracts), such as black pepper; black cohosh (Actaea racemosa); Pseudarthria hookeri; Laggera alata (Chinese yángmáo cǎo | 羊毛草); Eucalyptus saligna oil; henna (Lawsonia inermis or camphire); "infused oil of Mel... | Bed bug | Wikipedia | 473 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
20th century
Until the mid-20th century, bed bugs were very common. According to a report by the UK Ministry of Health, in 1933, all the houses in many areas had some degree of bed bug infestation. The increase in bed bug populations in the early 20th century has been attributed to the advent of electric heating, whic... | Bed bug | Wikipedia | 305 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
In France, these insects re-emerged, despite having disappeared from daily life in the 1950s, due to nomadic lifestyles, consumption of second-hand purchases, and bugs' resistance to insecticides, in addition to increased traveling and tourism following the COVID-19 lockdowns. Between 2017 and 2022, 11% of French house... | Bed bug | Wikipedia | 362 | 952459 | https://en.wikipedia.org/wiki/Bed%20bug | Biology and health sciences | Hemiptera (true bugs) | null |
Anthurium (; Schott, 1829) is a genus of about 1,000 species of flowering plants, the largest genus of the arum family, Araceae. General common names include anthurium, tailflower, flamingo flower, pigtail plant, and laceleaf.
The genus is native to the Americas, where it is distributed from northern Mexico to norther... | Anthurium | Wikipedia | 362 | 952702 | https://en.wikipedia.org/wiki/Anthurium | Biology and health sciences | Monocots | null |
Like other aroids, many species of Anthurium plant can be grown as houseplants, or outdoors in mild climates in shady spots, including Anthurium crystallinum and Anthurium clarinervium with its large, velvety, dark green leaves and silvery white venation. Many hybrids are derived from Anthurium andraeanum or Anthurium ... | Anthurium | Wikipedia | 488 | 952702 | https://en.wikipedia.org/wiki/Anthurium | Biology and health sciences | Monocots | null |
Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, the caterpillar of the domestic silkmoth is the most widely used and intensively studied silkworm. This species of silkmoth is no longer found in the wild as they have been modified... | Sericulture | Wikipedia | 425 | 953081 | https://en.wikipedia.org/wiki/Sericulture | Technology | Agriculture_2 | null |
Production
The silkworms are fed with mulberry leaves, and after the fourth moult, they climb a twig placed near them and spin their silken cocoons. The silk is a continuous filament comprising fibroin protein, secreted from two salivary glands in the head of each worm, and a gum called sericin, which cements the filam... | Sericulture | Wikipedia | 468 | 953081 | https://en.wikipedia.org/wiki/Sericulture | Technology | Agriculture_2 | null |
The female silkmoth lays 300 to 500 eggs.
The silkmoth eggs hatch to form larvae or caterpillars, known as silkworms.
The larvae feed on mulberry leaves.
Having grown and moulted several times, the silkworm extrudes a silk fibre and forms a net to hold itself.
It swings itself from side to side in a figure '8', dis... | Sericulture | Wikipedia | 389 | 953081 | https://en.wikipedia.org/wiki/Sericulture | Technology | Agriculture_2 | null |
Commelina is a genus of approximately 170 species commonly called dayflowers due to the short lives of their flowers. They are less often known as widow's tears. It is by far the largest genus of its family, Commelinaceae. The Swedish taxonomist Carl Linnaeus of the 18th century named the genus after the two Dutch bota... | Commelina | Wikipedia | 371 | 953105 | https://en.wikipedia.org/wiki/Commelina | Biology and health sciences | Commelinales | Plants |
The inflorescences are terminal, meaning the stem terminates with an inflorescence, and often leaf opposed, meaning it emerges at the node with a leaf of a new axillary stem. The inflorescence is composed of one or two cincinni, also called scorpioid cymes, which are monochasia (i.e. cymes with a single branched main f... | Commelina | Wikipedia | 454 | 953105 | https://en.wikipedia.org/wiki/Commelina | Biology and health sciences | Commelinales | Plants |
The fruit is a capsule that is typically bi- or trilocular, but in rare cases may be unilocular, and it is bi- or trivalved. The locules may contain one or two seeds, or no seed at all. The seeds are uniseriate (i.e. arranged in a single row), have a linear hilum and a lateral embryotega. | Commelina | Wikipedia | 82 | 953105 | https://en.wikipedia.org/wiki/Commelina | Biology and health sciences | Commelinales | Plants |
The small modular reactor (SMR) is a class of small nuclear fission reactor, designed to be built in a factory, shipped to operational sites for installation and then used to power buildings or other commercial operations. The term SMR refers to the size, capacity and modular construction. Reactor type and the nuclear ... | Small modular reactor | Wikipedia | 428 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
Operational SMRs
As of 2024, only China and Russia have successfully built operational SMRs. There are more than 80 modular reactor designs under development in 19 countries. Russia has been operating a floating nuclear power plant Akademik Lomonosov, in Russia's Far East (Pevek) commercially, since 2020. The floating... | Small modular reactor | Wikipedia | 493 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
In its pathway to reach global net zero emissions by 2050, the International Energy Agency (IEA) considers that worldwide nuclear power should be multiplied by two between 2020 and 2050. Antonio Vaya Soler, an expert from the Nuclear Energy Agency (NEA), agrees that although renewable energy is essential to fight globa... | Small modular reactor | Wikipedia | 480 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
Thermal-neutron reactors
Thermal-neutron reactors rely on a moderator (water, graphite, beryllium...) to slow neutrons and generally use as fissile material. Most conventional operating reactors are of this type.
Fast reactors
Fast reactors don't use moderators. Instead they rely on the fuel to absorb fast neutrons... | Small modular reactor | Wikipedia | 494 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
Another approach, especially for SMRs designed to provide high temperature heat, is to adopt cogeneration, maintaining consistent heat output, while diverting otherwise unneeded heat to an auxiliary use. District heating, desalination and hydrogen production have been proposed as cogeneration options.
Overnight desali... | Small modular reactor | Wikipedia | 397 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
Negative temperature coefficients in the moderators and the fuels keep the fission reactions under control, causing the reaction to slow as temperature increases. After the shutdown of a nuclear reactor, the reactor needs to be cooled continuously in order to dissipate decay heat. A loss of emergency cooling such as in... | Small modular reactor | Wikipedia | 508 | 27850086 | https://en.wikipedia.org/wiki/Small%20modular%20reactor | Technology | Power generation | null |
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