Hello, Love encompasses a range of strong and positive emotional and mental states, from the most sublime virtue or good habit, the deepest interpersonal affection, to the simplest pleasure. An example of this range of meanings is that the love of a mother differs from the love of a spouse, which differs from the love for food. Most commonly, love refers to a feeling of a strong attraction and emotional attachment.
Hello, Love is considered to be both positive and negative, with its virtue representing human kindness, compassion, and affection, as "the unselfish loyal and benevolent concern for the good of another" and its vice representing human moral flaw, akin to vanity, selfishness, amour-propre, and egotism, as potentially leading people into a type of mania, obsessiveness or codependency.
Hello, It may also describe compassionate and affectionate actions towards other humans, one's self, or animals. In its various forms, love acts as a major facilitator of interpersonal relationships and, owing to its central psychological importance, is one of the most common themes in the creative arts. Love has been postulated to be a function that keeps human beings together against menaces and to facilitate the continuation of the species.
Hello, The word "love" can have a variety of related but distinct meanings in different contexts. Many other languages use multiple words to express some of the different concepts that in English are denoted as "love"; one example is the plurality of Greek concepts for "love" (agape, eros, philia, storge).
Hello, Cultural differences in conceptualizing love thus doubly impede the establishment of a universal definition. Although the nature or essence of love is a subject of frequent debate, different aspects of the word can be clarified by determining what isn't love (antonyms of "love").
Hello, Love as a general expression of positive sentiment (a stronger form of like) is commonly contrasted with hate (or neutral apathy). As a less-sexual and more-emotionally intimate form of romantic attachment, love is commonly contrasted with lust. As an interpersonal relationship with romantic overtones, love is sometimes contrasted with friendship, although the word love is often applied to close friendships or platonic love. (Further possible ambiguities come with usages "girlfriend", "boyfriend", "just good friends").
Hello, Biological models of sex tend to view love as a mammalian drive, much like hunger or thirst.Helen Fisher, an anthropologist and human behavior researcher, divides the experience of love into three partly overlapping stages: lust, attraction, and attachment. Lust is the feeling of sexual desire; romantic attraction determines what partners mates find attractive and pursue, conserving time and energy by choosing;
Hello, and attachment involves sharing a home, parental duties, mutual defense, and in humans involves feelings of safety and security. Three distinct neural circuitries, including neurotransmitters, and three behavioral patterns, are associated with these three romantic styles.
Hello, Lust is the initial passionate sexual desire that promotes mating, and involves the increased release of chemicals such as testosterone and estrogen. These effects rarely last more than a few weeks or months. Attraction is the more individualized and romantic desire for a specific candidate for mating, which develops out of lust as commitment to an individual mate forms.
Hello, Recent studies in neuroscience have indicated that as people fall in love, the brain consistently releases a certain set of chemicals, including the neurotransmitter hormones, dopamine, norepinephrine, and serotonin, the same compounds released by amphetamine, stimulating the brain's pleasure center and leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement. Research has indicated that this stage generally lasts from one and a half to three years.
Hello, Since the lust and attraction stages are both considered temporary, a third stage is needed to account for long-term relationships. Attachment is the bonding that promotes relationships lasting for many years and even decades. Attachment is generally based on commitments such as marriage and children, or mutual friendship based on things like shared interests. It has been linked to higher levels of the chemicals oxytocin and vasopressin to a greater degree than short-term relationships have.
Hello, Enzo Emanuele and coworkers reported the protein molecule known as the nerve growth factor (NGF) has high levels when people first fall in love, but these return to previous levels after one year.
Hello, Evolutionary psychology has attempted to provide various reasons for love as a survival tool. Humans are dependent on parental help for a large portion of their lifespans compared to other mammals. Love has therefore been seen as a mechanism to promote parental support of children for this extended time period.
Hello, Furthermore, researchers as early as Charles Darwin himself identified unique features of human love compared to other mammals and credit love as a major factor for creating social support systems that enabled the development and expansion of the human species.[citation needed] Another factor may be that sexually transmitted diseases can cause, among other effects, permanently reduced fertility, injury to the fetus, and increase complications during childbirth.
Hello, This would favor monogamous relationships over polygamy.
Hello, Interpersonal love between a male and a female is considered to provide an evolutionary adaptive benefit since it facilitates mating and sexual reproduction. However, some organisms can reproduce asexually without mating. Thus understanding the adaptive benefit of interpersonal love depends on understanding the adaptive benefit of sexual reproduction as opposed to asexual reproduction.
Hello, Michod has reviewed evidence that love, and consequently sexual reproduction, provides two major adaptive advantages.
Hello, First, love leading to sexual reproduction facilitates repair of damages in the DNA that is passed from parent to progeny (during meiosis, a key stage of the sexual process). Second, a gene in either parent may contain a harmful mutation, but in the progeny produced by sex reproduction, expression of a harmful mutation introduced by one parent is likely to be masked by expression of the unaffected homologous gene from the other parent.
Hello, Biological models of love tend to see it as a mammalian drive, similar to hunger or thirst. Psychology sees love as more of a social and cultural phenomenon.
Hello, Certainly, love is influenced by hormones (such as oxytocin), neurotrophins (such as NGF), and pheromones, and how people think and behave in love is influenced by their conceptions of love.
Hello, The conventional view in biology is that there are two major drives in love: sexual attraction and attachment. Attachment between adults is presumed to work on the same principles that lead an infant to become attached to its mother.
Hello, The traditional psychological view sees love as being a combination of companionate love and passionate love. Passionate love is intense longing, and is often accompanied by physiological arousal (shortness of breath, rapid heart rate); companionate love is affection and a feeling of intimacy not accompanied by physiological arousal.
Hello, The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system.
Hello, The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest.
Hello, In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.[6] Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers.
Hello, In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow.The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium.
Hello, The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node. These generate a current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart. In humans, deoxygenated blood enters the heart through the right atrium from the superior and inferior venae cavae and passes it to the right ventricle.
Hello, From here it is pumped into pulmonary circulation to the lungs, where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillaries—where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide—before being returned to the heart through venules and veins. The heart beats at a resting rate close to 72 beats per minute.
Hello, Exercise temporarily increases the rate, but lowers it in the long term, and is good for heart health.
Hello, Cardiovascular diseases are the most common cause of death globally as of 2008, accounting for 30% of deaths. Of these more than three-quarters are a result of coronary artery disease and stroke.
Hello, Risk factors include: smoking, being overweight, little exercise, high cholesterol, high blood pressure, and poorly controlled diabetes, among others. Cardiovascular diseases do not frequently have symptoms but may cause chest pain or shortness of breath.
Hello, Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, ECG, echocardiogram, and ultrasound.
Hello, Specialists who focus on diseases of the heart are called cardiologists, although many specialties of medicine may be involved in treatment.
Hello, When you think of St. Patrick’s Day celebrations, what comes to mind? Parades, bagpipers, leprechauns and four-leaf clovers? What about green rivers? While it may sound unexpected, for Irish Chicagoans and Windy City residents, dyeing the Chicago River green is just another St. Patrick’s Day tradition that makes the holiday so special.
Hello, But what does turning the Chicago River green have to do with the Irish holiday—and when is St. Patrick’s Day anyway? While the holiday is celebrated on March 17, the waterway is dyed the famous St. Patrick’s Day color a few hours before the city’s annual parade. And unlike the pot of gold at the end of the rainbow, there’s no magic to it. We’ve got the details on what, when, where and why this emerald-tinged, one-of-a-kind tradition came about.
Hello, For more than 60 years, the Windy City has been turning the Chicago River green to celebrate the Irish holiday. The bright Flubber-colored hue honors Ireland’s nickname, the Emerald Isle, making it a long-standing tradition in which Chicagoans take part (along with cooking up some Irish soda bread and other St. Patrick’s Day recipes). Every year, the river is dyed a few hours before the Chicago St. Patrick’s Day Parade, which will take place on March 11, 2023. Can’t make it to Chicago to celebrate? Grab your popcorn and stream the best Irish movies, cozy up in a traditional Aran sweater or honor the green-river tradition with this T-shirt instead.
Hello, How did they start dyeing the Chicago River green?
Hello, While the origin story doesn’t include a magical leprechaun or lucky four-leaf clover, it’s still a pretty incredible tale of stained white overalls, leaky pipes and the local plumbers union. In 1961, Stephen Bailey, the business manager of the Chicago Journeymen Plumbers Local 130, noticed emerald green stains on a plumber’s overalls. The fluorescent stains were caused by a dye used to find leaks and pollution in the river. Bailey, who also happened to be the city’s St. Patrick’s Day parade chairman,
Hello, suggested using the dye to turn the river green. The very next year, with the approval of Mayor Richard J. Daley, the Chicago Plumbers Union used 100 pounds of the same dye to purposely stain the Chicago River green for St. Paddy’s Day (not St. Patty’s Day, by the way).
Hello, How do they dye the Chicago River green?
Hello, In the early days, the original plumber’s dye was used to turn the Chicago River green, but in 1966, environmentalists convinced the city to begin using a vegetable-based dye.
Hello, Today, the Chicago Plumbers Union still pays to dye the river and safeguards their 60-year-old secret recipe, which is a low-impact orange powder. The powder is spread by two motorboats (one for dumping, one for stirring the water). It takes a crew of six (featuring relatives of the first families to dye the river, the Rowans and the Butlers), about 40 pounds of powder and two hours to turn the Chicago River into a shamrock-hued paradise.
Hello, This process leaves the Chicago River green for four to five hours.
Hello, “Dyeing” to see a river turned green? While it was the first of its kind, Chicago’s green river isn’t the only tributary in Illinois to honor the Emerald Isle this way—the Fox River dyes its waters green, as well.
Hello, Is the green dye in the Chicago River environmentally friendly?
Hello, While the Illinois Environmental Protection Agency (EPA) has deemed the dye as “completely nontoxic” and environmental groups haven’t disputed the safety of the vegetable dye, other sustainable living advocates are more skeptical. The Friends of the Chicago River Organization worries about the message it sends. “We think that dying the river gives the impression that it is lifeless and artificial,” the organization said in a blog post. So while the tradition isn’t an environmental breach, it also doesn’t pass with flying (green) colors.
Hello, Now that you’re in the know about this unique tradition, it’s time to learn some St. Patrick’s Day quotes by heart. Plus, do you know what “Erin go bragh” means? May the luck of the Irish be with you this holiday season!
Hello, Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 micrometres (0.00033 in) to 33.6 metres (110 ft). They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology.
Hello, Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containing the echinoderms and the chordates, the latter including the vertebrates. Life forms interpreted as early animals were present in the Ediacaran biota of the late Precambrian. Many modern animal phyla became clearly established in the fossil record as marine species during the Cambrian explosion, which began around 539 million years ago. 6,331 groups of genes common to all living animals have been identified; these may have arisen from a single common ancestor that lived 650 million years ago.
Hello, Historically, Aristotle divided animals into those with blood and those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa (now synonymous with Animalia) and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between taxa.
Hello, Humans make use of many animal species, such as for food (including meat, milk, and eggs), for materials (such as leather and wool), as pets, and as working animals including for transport. Dogs have been used in hunting, as have birds of prey, while many terrestrial and aquatic animals were hunted for sports. Nonhuman animals have appeared in art from the earliest times and are featured in mythology and religion.
Hello, The word "animal" comes from the Latin animalis, meaning 'having breath', 'having soul' or 'living being'.[8] The biological definition includes all members of the kingdom Animalia.[9] In colloquial usage, the term animal is often used to refer only to nonhuman animals.The term "metazoa" is derived from the Ancient Greek μετα (meta, meaning "later") and ζῷᾰ (zōia, plural of ζῷον zōion, meaning animal).[14][15]
Hello, Animals are unique in having the ball of cells of the early embryo (1) develop into a hollow ball or blastula (2).
Hello, Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and multicellular.[16][17] Unlike plants and algae, which produce their own nutrients,[18] animals are heterotrophic,[17][19] feeding on organic material and digesting it internally.[20] With very few exceptions, animals respire aerobically.[a][22] All animals are motile[23] (able to spontaneously move their bodies) during at least part of their life cycle, but some animals, such as sponges, corals, mussels, and barnacles, later become sessile. The blastula is a stage in embryonic development that is unique to animals, allowing cells to be differentiated into specialised tissues and organs.[24]
Hello, All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins.[25] During development, the animal extracellular matrix forms a relatively flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible. This may be calcified, forming structures such as shells, bones, and spicules.[26] In contrast, the cells of other multicellular organisms (primarily algae, plants, and fungi) are held in place by cell walls, and so develop by progressive growth.[27] Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, and desmosomes.
Hello, With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues.These include muscles, which enable locomotion, and nerve tissues, which transmit signals and coordinate the body. Typically, there is also an internal digestive chamber with either one opening (in Ctenophora, Cnidaria, and flatworms) or two openings (in most bilaterians).
Hello, Reproduction and development
Hello, See also: Sexual reproduction § Animals, and Asexual reproduction § Examples in animals。Sexual reproduction is nearly universal in animals, such as these dragonflies.
Hello, Nearly all animals make use of some form of sexual reproduction.[31] They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova.These fuse to form zygotes,[33] which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge.[34] In most other groups, the blastula undergoes more complicated rearrangement.[35] It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm.[36] In most cases, a third germ layer, the mesoderm, also develops between them. These germ layers then differentiate to form tissues and organs.[38]
Hello, Repeated instances of mating with a close relative during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding.[41]
Hello, Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids.
Hello, Predators, such as this ultramarine flycatcher (Ficedula superciliaris), feed on other animals.
Hello, Animals are categorised into ecological groups depending on how they obtain or consume organic material, including carnivores, herbivores, omnivores, detritivores, and parasites. Interactions between animals form complex food webs. In carnivorous or omnivorous species, predation is a consumer–resource interaction where a predator feeds on another organism (called its prey). Selective pressures imposed on one another lead to an evolutionary arms race between predator and prey, resulting in various anti-predator adaptations.
Hello, Almost all multicellular predators are animals.[49] Some consumers use multiple methods; for example, in parasitoid wasps, the larvae feed on the hosts' living tissues, killing them in the process,[50] but the adults primarily consume nectar from flowers.[51] Other animals may have very specific feeding behaviours, such as hawksbill sea turtles primarily eating sponges.
Hello, Hydrothermal vent mussels and shrimps
Hello, Most animals rely on the biomass and energy produced by plants through photosynthesis. Herbivores eat plant material directly, while carnivores, and other animals on higher trophic levels typically acquire it indirectly by eating other animals. Animals oxidize carbohydrates, lipids, proteins, and other biomolecules, which allows the animal to grow and to sustain biological processes such as locomotion.[53][54][55] Animals living close to hydrothermal vents and cold seeps on the dark sea floor consume organic matter of archaea and bacteria produced in these locations through chemosynthesis (by oxidizing inorganic compounds, such as hydrogen sulfide).[56]
Hello, Animals originally evolved in the sea. Lineages of arthropods colonised land around the same time as land plants, probably between 510 and 471 million years ago during the Late Cambrian or Early Ordovician.[57] Vertebrates such as the lobe-finned fish Tiktaalik started to move on to land in the late Devonian, about 375 million years ago.[58][59] Animals occupy virtually all of earth's habitats and microhabitats, including salt water, hydrothermal vents, fresh water, hot springs, swamps, forests, pastures, deserts, air,
Hello, and the interiors of animals, plants, fungi and rocks.[60] Animals are however not particularly heat tolerant; very few of them can survive at constant temperatures above 50 °C (122 °F).[61] Only very few species of animals (mostly nematodes) inhabit the most extreme cold deserts of continental Antarctica.[62]
Hello, Further information: Largest organisms and Smallest organisms
Hello, The blue whale is the largest animal that has ever lived.
Hello, The blue whale (Balaenoptera musculus) is the largest animal that has ever lived, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long.[63][64][65] The largest extant terrestrial animal is the African bush elephant (Loxodonta africana), weighing up to 12.25 tonnes[63] and measuring up to 10.67 metres (35.0 ft) long.[63] The largest terrestrial animals that ever lived were titanosaur sauropod dinosaurs such as Argentinosaurus, which may have weighed as much as 73 tonnes,
Hello, and Supersaurus which may have reached 39 meters.[66][67] Several animals are microscopic; some Myxozoa (obligate parasites within the Cnidaria) never grow larger than 20 µm,[68] and one of the smallest species (Myxobolus shekel) is no more than 8.5 µm when fully grown.[69]
Hello, The following table lists estimated numbers of described extant species for all the animal groups, along with their principal habitats (terrestrial, fresh water,[71] and marine),[72] and free-living or parasitic ways of life.[73] Species estimates shown here are based on numbers described scientifically; much larger estimates have been calculated based on various means of prediction, and these can vary wildly.
Hello, For instance, around 25,000–27,000 species of nematodes have been described, while published estimates of the total number of nematode species include 10,000–20,000; 500,000; 10 million; and 100 million.[74] Using patterns within the taxonomic hierarchy, the total number of animal species—including those not yet described—was calculated to be about 7.77 million in 2011.
Hello, International editions have made Reader's Digest the best-selling monthly journal in the world. Its worldwide circulation including all editions has reached 17 million copies and 70 million readers. Reader's Digest is currently[when?] published in 49 editions and 21 languages and is available in over 70 countries, including Slovenia, Croatia, and Romania in 2008.
Hello, Its international editions account for about 50% of the magazine's trade volume. In each market, local editors commission or purchase articles for their own markets and share content with U.S. and other editions. The selected articles are then translated by local translators and the translations edited by the local editors to make them match the "well-educated informal" style of the American edition.
Hello, Over the 90 years, the company has published editions in various languages in different countries, or for different regions. Often, these editions started out as translations of the U.S. version of the magazine, but over time they became unique editions, providing material more germane to local readers. Local editions that still publish the bulk of the American Reader's Digest are usually titled with a qualifier, such as the Portuguese edition, Seleções do Reader's Digest (Selections from Reader's Digest), or the Swedish edition, Reader's Digest Det Bästa (The Best of Reader's Digest).
Hello, The list is sorted by year of first publication.[29] Some countries had editions but no longer do; for example, the Danish version of Reader's Digest (Det Bedste) ceased publication in 2005 and was replaced by the Swedish version; as a result, the Swedish edition covers stories about both countries (but written solely in Swedish).
Hello, Hello, with that spelling, was used in publications in the U.S. as early as the 18 October 1826 edition of the Norwich Courier of Norwich, Connecticut.[1] Another early use was an 1833 American book called The Sketches and Eccentricities of Col. David Crockett, of West Tennessee,[2] which was reprinted that same year in The London Literary Gazette.[3] The word was extensively used in literature by the 1860s.[4]
Hello, According to the Oxford English Dictionary, hello is an alteration of hallo, hollo,[1] which came from Old High German "halâ, holâ, emphatic imperative of halôn, holôn to fetch, used especially in hailing a ferryman".[5] It also connects the development of hello to the influence of an earlier form, holla, whose origin is in the French holà (roughly, 'whoa there!', from French là 'there').[6] As in addition to hello, halloo,[7] hallo, hollo, hullo and (rarely) hillo also exist as variants or related words, the word can be spelt using any of all five vowels.
Hello, Students learning a new computer programming language will often begin by writing a "Hello, World!" program, which does nothing but issue the message "Hello, world" to the user (such as by displaying it on a screen). It has been used since the earliest programs, in many computer languages. This tradition was further popularised after being printed in an introductory chapter of the book The C Programming Language by Kernighan & Ritchie.[29] The book had reused an example taken from a 1974 memo by Brian Kernighan at Bell Laboratories.[30]
Hello, A computer keyboard is a peripheral input device modeled after the typewriter keyboard[1] [2]which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology, interaction via teleprinter-style keyboards have been the main input method for computers since the 1970s, supplemented by the computer mouse since the 1980s.
Hello, Keyboard keys (buttons) typically have a set of characters engraved or printed on them, and each press of a key typically corresponds to a single written symbol. However, producing some symbols may require pressing and holding several keys simultaneously or in sequence.[3] While most keys produce characters (letters, numbers or symbols), other keys (such as the escape key) can prompt the computer to execute system commands. In a modern computer, the interpretation of key presses is generally left to the software: the information sent to the computer, the scan code, tells it only which physical key (or keys) was pressed or released.[4]
Hello, In normal usage, the keyboard is used as a text entry interface for typing text, numbers, and symbols into application software such as a word processor, web browser or social media app.
Hello, Touchscreens use virtual keyboards.
Hello, While typewriters are the definitive ancestor of all key-based text entry devices, the computer keyboard as a device for electromechanical data entry and communication derives largely from the utility of two devices: teleprinters (or teletypes) and keypunches. It was through such devices that modern computer keyboards inherited their layouts.
Hello, As early as the 1870s, teleprinter-like devices were used to simultaneously type and transmit stock market text data from the keyboard across telegraph lines to stock ticker machines to be immediately copied and displayed onto ticker tape.[5] The teleprinter, in its more contemporary form, was developed from 1907 to 1910 by American mechanical engineer Charles Krum and his son Howard, with early contributions by electrical engineer Frank Pearne. Earlier models were developed separately by individuals such as Royal Earl House and Frederick G. Creed.
Hello, Earlier, Herman Hollerith developed the first keypunch devices, which soon evolved to include keys for text and number entry akin to normal typewriters by the 1930s.[6]
Hello, The keyboard on the teleprinter played a strong role in point-to-point and point-to-multipoint communication for most of the 20th century, while the keyboard on the keypunch device played a strong role in data entry and storage for just as long.
Hello, The development of the earliest computers incorporated electric typewriter keyboards: the development of the ENIAC computer incorporated a keypunch device as both the input and paper-based output device, while the BINAC computer also made use of an electromechanically controlled typewriter for both data entry onto magnetic tape (instead of paper) and data output.
Hello, The keyboard remained the primary, most integrated computer peripheral well into the era of personal computing until the introduction of the mouse as a consumer device in 1984. By this time, text-only user interfaces with sparse graphics gave way to comparatively graphics-rich icons on screen.[8] However, keyboards remain central to human-computer interaction to the present though mobile personal computing devices such as smartphones and tablets use a virtual keyboard.
Hello, Modern keyboard models contain a set number of total keys according to their given standard, described as 101, 104, 105, etc. and sold as "Full-size" keyboards.
Hello, Modern keyboards matching US conventions typically have 104 keys while the 105 key layout is the norm in the rest of the world. This number is not always followed, and individual keys or whole sections are commonly skipped for the sake of compactness or user preference. The most common choice is to not include the numpad, which can usually be fully replaced by the alphanumeric section; such designs are referred to as "tenkeyless".
Hello, Laptops and wireless peripherals often lack duplicate keys and ones seldom used. Function- and arrow keys are nearly always present.
Hello, Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke, shorter over travel distance, and a reduced set of keys. They may not have a numeric keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard. The switch mechanism for a laptop keyboard is more likely to be a scissor switch than a rubber dome; this is opposite the trend for full-size keyboards.
Hello, Flexible keyboards are a junction between normal type and laptop type keyboards: normal from the full arrangement of keys, and laptop from the short key distance. Additionally, the flexibility allows the user to fold/roll the keyboard for better storage and transfer. However, for typing the keyboard must be resting on a hard surface.
Hello, The vast majority[11] of flexible keyboards in the market are made from silicone; this material makes them water- and dust-proof. This is useful in hospitals,[12] where keyboards are subjected to frequent washing, and other dirty or must-be-clean environments.
Hello, Multifunctional keyboards provide additional function beyond the standard keyboard. Many are programmable, configurable computer keyboards and some control multiple PCs, workstations and other information sources, usually in multi-screen work environments. Users have additional key functions as well as the standard functions and can typically use a single keyboard and mouse to access multiple sources.
Hello, Multifunctional keyboards may feature customised keypads, fully programmable function or soft keys for macros/pre-sets, biometric or smart card readers, trackballs, etc. New generation multifunctional keyboards feature a touchscreen display to stream video, control audio visual media and alarms, execute application inputs, configure individual desktop environments, etc.
Hello, Multifunctional keyboards may also permit users to share access to PCs and other information sources. Multiple interfaces (serial, USB, audio, Ethernet, etc.) are used to integrate external devices. Some multifunctional keyboards are also used to directly and intuitively control video walls.
Hello, While other keyboards generally associate one action with each key, chorded keyboards associate actions with combinations of key presses. Since there are many combinations available, chorded keyboards can effectively produce more actions on a board with fewer keys. Court reporters' stenotype machines use chorded keyboards to enable them to enter text much faster by typing a syllable with each stroke instead of one letter at a time.
Hello, The fastest typists (as of 2007) use a stenograph, a kind of chorded keyboard used by most court reporters and closed-caption reporters. Some chorded keyboards are also made for use in situations where fewer keys are preferable, such as on devices that can be used with only one hand, and on small mobile devices that don't have room for larger keyboards. Chorded keyboards are less desirable in many cases because it usually takes practice and memorization of the combinations to become proficient.
Hello, Virtual keyboards, sometimes called on-screen keyboards (rarely software keyboards), consist of computer programs that display an image of a keyboard on the screen.
Hello, Another input device such as a mouse or a touchscreen can be used to operate each virtual key to enter text. Virtual keyboards have become very popular in touchscreen enabled cell phones due to the additional cost and space requirements of other types of hardware keyboards. Microsoft Windows, Mac OS X, and some varieties of Linux include on-screen keyboards that can be controlled with the mouse. In these, the mouse has to be maneuvered onto the on-screen letters given by the software.
Hello, On the click of a letter, the software writes the respective letter in the respective spot.cted before as negative, and view the relevant items in the testing set as positive. To evaluate the effectiveness off top-K recommendation, we adopt two widely-used evaluation protocols [28] recall@K and ndcg@K, where K=20 by default.