147-424: Tsetse ( / ˈ s iː t s i / SEET -see , US : / ˈ t s iː t s i / TSEET -see or UK : / ˈ t s ɛ t s ə / TSET -sə ) (sometimes spelled tzetze ; also known as tik-tik flies) are large, biting flies that inhabit much of tropical Africa . Tsetse flies include all the species in the genus Glossina , which are placed in their own family, Glossinidae . The tsetse
294-707: A cot–caught merger , which is rapidly spreading throughout the whole country. However, the South, Inland North, and a Northeastern coastal corridor passing through Rhode Island, New York City, Philadelphia, and Baltimore typically preserve an older cot–caught distinction. For that Northeastern corridor, the realization of the THOUGHT vowel is particularly marked , as depicted in humorous spellings, like in tawk and cawfee ( talk and coffee ), which intend to represent it being tense and diphthongal : [oə] . A split of TRAP into two separate phonemes , using different
441-520: A pronunciations for example in gap [æ] versus gas [eə] , further defines New York City as well as Philadelphia–Baltimore accents. Most Americans preserve all historical /r/ sounds, using what is known as a rhotic accent . The only traditional r -dropping (or non-rhoticity) in regional U.S. accents variably appears today in eastern New England , New York City , and some of the former plantation South primarily among older speakers (and, relatedly, some African-American Vernacular English across
588-631: A complex phenomenon of "both convergence and divergence": some accents are homogenizing and leveling , while others are diversifying and deviating further away from one another. Having been settled longer than the American West Coast, the East Coast has had more time to develop unique accents, and it currently comprises three or four linguistically significant regions, each of which possesses English varieties both different from each other as well as quite internally diverse: New England ,
735-447: A consonant, such as in pearl , car and fort . Non-rhotic American accents, those that do not pronounce ⟨r⟩ except before a vowel, such as some accents of Eastern New England , New York City , and African-Americans , and a specific few (often older ones) spoken by Southerners , are often quickly noticed by General American listeners and perceived as sounding especially ethnic, regional, or antiquated. Rhoticity
882-409: A few hours, and is almost never observed outside of the laboratory. Tsetse next develops a hard external case, the puparium, and become pupae - small, hard-shelled oblongs with two distinctively small, dark lobes at the tail (breathing) end. Tsetse pupae are under 1 centimetre ( 1 ⁄ 2 in) long. Within the puparial shell, tsetse complete the last two larval instars and the pupal stage. At
1029-454: A full adult) occurs without feeding, with only the nutrition provided by the mother fly. She must get enough energy for her own survival (in addition to the needs of her developing offspring), as well as for the stored resources that her offspring will require until they emerge as adults. Technically, these insects undergo the standard development process of insects, beginning with oocyte formation, ovulation, fertilization, and development of
1176-422: A grub-like state, parasitizing larger insects. The only time they ever come out of their host insect is to extend their fused heads and thoraces for males to notice. The males are also parasites, but they eventually will leave their host to seek their female counterparts. Because of this, they still retain the ability to fly. Male strepsipterans uniquely possess two hindwings, while their forewings have taken on
1323-413: A hard outer shell (called the puparial case ), within which they complete their morphological transformations into adult flies. The larval life stage has a variable duration, generally 20 to 30 days, and the larvae must rely on stored resources during this time. The importance of the richness and quality of blood to this stage can be seen; all tsetse development (prior to emerging from the puparial case as
1470-591: A merger with the THOUGHT ( caught ) set. Having taken place prior to the unrounding of the cot vowel, it results in lengthening and perhaps raising, merging the more recently separated vowel into the THOUGHT vowel in the following environments: before many instances of /f/ , /θ/ , and particularly /s/ (as in Austria, cloth, cost, loss, off, often, etc.), a few instances before /ŋ/ (as in strong, long, wrong ), and variably by region or speaker in gone , on , and certain other words. Unlike American accents,
1617-636: A nice day , for sure); many are now distinctly old-fashioned (swell, groovy). Some English words now in general use, such as hijacking, disc jockey , boost, bulldoze and jazz , originated as American slang. American English has always shown a marked tendency to use words in different parts of speech and nouns are often used as verbs . Examples of nouns that are now also verbs are interview, advocate, vacuum, lobby, pressure, rear-end, transition, feature, profile, hashtag, head, divorce, loan, estimate, X-ray, spearhead, skyrocket, showcase, bad-mouth, vacation , major, and many others. Compounds coined in
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#17327753890591764-414: A perturbation. This would allow the haltere-initiated reflex to occur, correcting the imagined perturbation. The fly would then be able to execute its turn in the desired direction. This is not how flies actually turn. Mureli and Fox (2015) showed that flies are still capable of performing planned turns even when their halteres have been removed entirely. The way in which rotation sensation is accomplished
1911-413: A pregnant tsetse and her offspring, so all newly emerged tsetse adults are free of infection. An uninfected fly that feeds on an infected vertebrate animal may acquire trypanosomes in its proboscis or gut. These trypanosomes, depending on the species, may remain in place, move to a different part of the digestive tract, or migrate through the tsetse body into the salivary glands. When an infected tsetse bites
2058-480: A process of extensive dialect mixture and leveling in which English varieties across the colonies became more homogeneous compared with the varieties in Britain. English thus predominated in the colonies even by the end of the 17th century's first immigration of non-English speakers from Western Europe and Africa. Additionally, firsthand descriptions of a fairly uniform American English (particularly in contrast to
2205-680: A series of other vowel shifts in the same region, known by linguists as the " Inland North ". The Inland North shares with the Eastern New England dialect (including Boston accents ) a backer tongue positioning of the GOOSE /u/ vowel (to [u] ) and the MOUTH /aʊ/ vowel (to [ɑʊ~äʊ] ) in comparison to the rest of the country. Ranging from northern New England across the Great Lakes to Minnesota, another Northern regional marker
2352-425: A single gene (Ubx), which when deactivated results in the formation of a hindwing instead. Because just a single gene is responsible for this change, it is easy to imagine a small mutation here leading to the formation of the first halteres. Though no other structure with entirely the same function and morphology as halteres has been observed in nature, they have evolved at least twice in the class Insecta , once in
2499-513: A static figure is placed in the field of view of a fly, its ability to stabilize a moving background is restored. This indicates that although halteres are not required for motion vision processing, they do contribute to it in a context-dependent manner, even when the behavior is separated from body rotations. Context determines whether the fly will use its halteres or vision as the primary source of body/head position information. The necessity of halteres in flight has been well documented, yet little
2646-525: A survey, completed in 2003, polling English speakers across the United States about their specific everyday word choices, hoping to identify regionalisms. The study found that most Americans prefer the term sub for a long sandwich, soda (but pop in the Great Lakes region and generic coke in the South) for a sweet and bubbly soft drink , you or you guys for the plural of you (but y'all in
2793-425: A susceptible host, the fly may regurgitate part of a previous blood meal that contains trypanosomes, or may inject trypanosomes in its saliva. Inoculation must contain a minimum of 300 to 450 individual trypanosomes to be successful, and may contain up to 40,000 cells. In the case of T. b. brucei infecting G. p. gambiensis , during this time the parasite changes the proteome contents of the fly's head. This may be
2940-437: A tsetse bite leading to an inoculation in the subcutaneous tissue. The infection moves into the lymphatic system , leading to a characteristic swelling of the lymph glands called Winterbottom's sign . The infection progresses into the blood stream and eventually crosses into the central nervous system and invades the brain leading to extreme lethargy and eventually to death . The species Trypanosoma brucei , which causes
3087-453: A variation of American English in these islands. In 2021, about 245 million Americans, aged 5 or above, spoke English at home: a majority of the United States total population of roughly 330 million people. The United States has never had an official language at the federal level, but English is commonly used at the federal level and in states without an official language. 32 of the 50 states, in some cases as part of what has been called
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#17327753890593234-577: A variety of wing-haltere phasing. These observed differences in wing-haltere coordination suggest that differences in sensory neuron output also exist between species. This means that the decoding mechanisms used by the central nervous system to interpret such movements and produce adequate motor output probably also vary depending on phylogeny . The general structure of halteres are well recognized, but much variability exists between species. The more ancient family groups, such as Tipuloidea (crane flies), possess halteres with rather long stalks. This causes
3381-474: Is also altered: Production of aromatic L-amino acid decarboxylase - involved in dopamine and serotonin synthesis - and α-methyldopa hypersensitive protein was induced. This is very similar to the alterations in other dipteran vectors' head proteomes under infection by other eukaryotic parasites of mammals, found in another study by the same team in the same year. The trypanosomes are injected into vertebrate muscle tissue, but make their way, first into
3528-654: Is also associated with the United States, perhaps mostly in the Midwest and the South. American accents that have not undergone the cot–caught merger (the lexical sets LOT and THOUGHT ) have instead retained a LOT – CLOTH split : a 17th-century distinction in which certain words (labeled as the CLOTH lexical set ) separated away from the LOT set. The split, which has now reversed in most British English, simultaneously shifts this relatively recent CLOTH set into
3675-664: Is also home to a creole language known commonly as Hawaiian Pidgin , and some Hawaii residents speak English with a Pidgin-influenced accent. American English also gave rise to some dialects outside the country, for example, Philippine English , beginning during the American occupation of the Philippines and subsequently the Insular Government of the Philippine Islands ; Thomasites first established
3822-563: Is an obligate parasite , which lives by feeding on the blood of vertebrate animals. Tsetse has been extensively studied because of their role in transmitting disease. They have pronounced economic and public health impacts in sub-Saharan Africa as the biological vectors of trypanosomes , causing human and animal trypanosomiasis . Tsetse can be distinguished from other large flies by two easily-observed features: Primarily, tsetse fold their wings over their abdomens completely when they are resting (so that one wing rests directly on top of
3969-597: Is another order of insect which has evolved flight with only two wings: strepsipterans , or stylops; they are the only other organisms that possess two wings and two halteres. The strepsipterans have adapted their forewings into halteres, whereas dipterans have adapted their hindwings into halteres. This unique structure which detects rotations/perturbations during flight has never been described in nature elsewhere, though many flying insects have been shown to detect Coriolis forces from their non-specialised wings. Halteres are able to sense small deviations in body position using
4116-463: Is called sleeping sickness . In animals, tsetse-vectored trypanosomiases include nagana , souma (a French term which may not be a distinct condition), and surra according to the animal infected and the trypanosome species involved. The usage is not strict and while nagana generally refers to the disease in cattle and horses it is commonly used for any of the animal trypanosomiases. Trypanosomes are animal parasites , specifically protozoans of
4263-538: Is common in most American accents despite being now rare in England because, during the 17th-century British colonization, nearly all dialects of English were rhotic, and most North American English simply remained that way. The preservation of rhoticity in North America was also supported by continuing waves of rhotic-accented Scotch-Irish immigrants, most intensely during the 18th century (and moderately during
4410-585: Is experimentally deactivated, the haltere will develop into a fully formed wing. This single homeotic gene change results in a radically different phenotype , but also begins to give us some insight into how the ancestors of flies' hindwings may have originally evolved into halteres. Though it is clear that Ubx is the primary gene responsible for hindwing formation, Ubx also regulates other genes once expressed. Weatherbee (1998) postulated that differences in Ubx expression patterns or levels may not be responsible for
4557-1054: Is known about their use in other behaviors such as walking. Certain flies in the families Muscidae , Anthomyiidae , Calliphoridae , Sarcophagidae , Tachinidae , and Micropezidae have been documented to oscillate their wings while walking in addition to during flight. The oscillation of the haltere is similar in amplitude and frequency during walking and flight for these flies, and the halteres always oscillate when walking or when flying. All other families of Diptera never oscillate their halteres while walking, but always do so while flying. Flesh flies are among those that oscillate their halteres while walking, and also perform more poorly at certain walking tasks when their halteres are removed. In contrast, fruit flies , which do not oscillate their halteres when walking, do not exhibit any differences in ability when their halteres are removed. This indicates that haltere inputs are behaviorally relevant to those species which oscillate them while walking and that they aid those individuals in walking behavior. Flies in
Tsetse fly - Misplaced Pages Continue
4704-402: Is not yet well understood. However, since the sexual phase of the trypanosome life cycle occurs within the tsetse host, biological transmission is a required step in the life cycle of the tsetse-vectored trypanosomes. The cycle of biological transmission of trypanosomiasis involves two phases, one inside the tsetse host and the other inside the vertebrate host. Trypanosomes are not passed between
4851-420: Is often identified by Americans as a "country" accent, and is defined by the /aɪ/ vowel losing its gliding quality : [aː] , the initiation event for a complicated Southern vowel shift, including a " Southern drawl " that makes short front vowels into distinct-sounding gliding vowels . The fronting of the vowels of GOOSE , GOAT , MOUTH , and STRUT tends to also define Southern accents as well as
4998-433: Is rotated, they are able to maintain their head position so that the object remains focused and upright. Hengstenberg (1988) found that in the roll direction of rotation, the flies' ability to maintain their head position in response to body motion was only observed at speeds above 50 degrees per second and their ability peaked at 1500 degrees per second. When halteres were removed at the bulb (to retain intact sensory organs at
5145-476: Is sent to the central nervous system to be interpreted. Chordotonal organs detect and transmit distortions in their position/shape in the same way that campaniform sensilla do. They differ slightly at their site of detection. Chordotonal organs, unlike campaniform sensilla, exist beneath the cuticle and typically respond to stretch as opposed to distortion or bending. Their sensory nerve endings attach between two internal points and when those points are stretched,
5292-463: Is that there are five distinct sensory fields located at the base of the haltere. These fields, which actually contain the majority of campaniform sensilla found on the exoskeleton of blowflies (more than 400 campaniform sensilla per haltere), are activated in response to strain created by movements at the haltere base in different directions (due to Coriolis forces acting on the end knobs). Campaniform sensilla are cap-shaped protrusions located on
5439-411: Is the common language at home, in public, and in government. Halteres Halteres ( / h æ l ˈ t ɪər iː z / ; singular halter or haltere ) (from Ancient Greek : ἁλτῆρες , hand-held weights to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide information about body rotations during flight. Insects of
5586-469: Is the variable fronting of /ɑ/ before /r/ , for example, appearing four times in the stereotypical Boston shibboleth Park the car in Harvard Yard . Several other phenomena serve to distinguish regional U.S. accents. Boston , Pittsburgh , Upper Midwestern , and Western U.S. accents have fully completed a merger of the LOT vowel with the THOUGHT vowel ( /ɑ/ and /ɔ/ , respectively):
5733-625: The Coriolis effect . The insect detects this force with sensory organs called campaniform sensilla and chordotonal organs located at the base of the halteres and uses this information to interpret and correct its position in space. Halteres provide rapid feedback to the wing-steering muscles, as well as to the muscles responsible for stabilizing the head. The majority of insects have two pairs of wings. Flies possess only one set of lift-generating wings and one set of halteres. The order name for flies, "Diptera", literally means "two wings", but there
5880-611: The English language native to the United States. English is the most widely spoken language in the United States ; the de facto common language used in government, education, and commerce; and an official language in 32 of the 50 U.S. states . Since the late 20th century, American English has become the most influential form of English worldwide. Varieties of American English include many patterns of pronunciation, vocabulary, grammar and particularly spelling that are unified nationwide but distinct from other English dialects around
6027-482: The English-only movement , have adopted legislation granting official or co-official status to English. Typically only "English" is specified, not a particular variety like American English. (From 1923 to 1969, the state of Illinois recognized its official language as "American", meaning American English.) Puerto Rico is the largest example of a United States territory in which another language – Spanish –
Tsetse fly - Misplaced Pages Continue
6174-841: The Florissant Formation in North America and the Enspel Lagerstätte of Germany, dating to the late Eocene and late Oligocene respectively. Glossina is almost entirely restricted to wooded grasslands and forested areas of the Afrotropics . As of 1990, tsetse flies were reported from a maximum latitude of approximately 15° north in Senegal (Niayes Region), to a minimum of 28.5° south in South Africa (KwaZulu-Natal Province). Only two subspecies - G. f. fuscipes and G. m. submorsitans - are present in
6321-622: The Mid-Atlantic states (including a New York accent as well as a unique Philadelphia–Baltimore accent ), and the South . As of the 20th century, the middle and eastern Great Lakes area , Chicago being the largest city with these speakers, also ushered in certain unique features, including the fronting of the LOT /ɑ/ vowel in the mouth toward [a] and tensing of the TRAP /æ/ vowel wholesale to [eə] . These sound changes have triggered
6468-551: The Native American languages . Examples of such names are opossum , raccoon , squash , moose (from Algonquian ), wigwam , and moccasin . American English speakers have integrated traditionally non-English terms and expressions into the mainstream cultural lexicon; for instance, en masse , from French ; cookie , from Dutch ; kindergarten from German , and rodeo from Spanish . Landscape features are often loanwords from French or Spanish, and
6615-710: The Reduviidae , members of the Hemiptera . Animal trypanosomiasis , also called nagana when it occurs in bovine cattle or horses or sura when it occurs in domestic pigs , is caused by several trypanosome species. These diseases reduce the growth rate, milk productivity, and strength of farm animals, generally leading to the eventual death of the infected animals. Certain species of cattle are called trypanotolerant because they can survive and grow even when infected with trypanosomes although they also have lower productivity rates when infected. The course of
6762-722: The francophile tastes of the 19th century Victorian era Britain (for example they preferred programme for program , manoeuvre for maneuver , cheque for check , etc.). AmE almost always uses -ize in words like realize . BrE prefers -ise , but also uses -ize on occasion (see: Oxford spelling ). There are a few differences in punctuation rules. British English is more tolerant of run-on sentences , called " comma splices " in American English, and American English prefers that periods and commas be placed inside closing quotation marks even in cases in which British rules would place them outside. American English also favors
6909-467: The gyroscopic properties of moving mass. What this means is that halteres beat up and down in time with the flapping of the wings along a linear pathway, but when the fly's body begins to rotate, the path of the beating halteres also changes. Now, instead of the halteres following a linear path, they begin to follow a curved path. The larger the perturbation they experience, the farther the halteres move from their original linear path. During these periods,
7056-670: The lymphatic system , then into the bloodstream, and eventually into the brain. The disease causes the swelling of the lymph glands, emaciation of the body, and eventually leads to death. Uninfected tsetse may bite the infected animal prior to its death and acquire the disease, thereby closing the transmission cycle. The tsetse-vectored trypanosomiases affect various vertebrate species including humans, antelopes, bovine cattle, camels, horses, sheep, goats, and pigs. These diseases are caused by several different trypanosome species that may also survive in wild animals such as crocodiles and monitor lizards. The diseases have different distributions across
7203-491: The thorax is separated into different segments. One of the things that the Hox gene Ultrabithorax (Ubx) is responsible for, is specifying the identity of the third thoracic segment of their body. Proper hindwing development in a number of insect species is dependent on Ubx , including butterflies, beetles, and flies. In fruit flies, ( Ubx ) is responsible for the formation of the halteres during metamorphosis . If this gene
7350-764: The 18th century; apartment , shanty in the 19th century; project, condominium , townhouse , mobile home in the 20th century; and parts thereof ( driveway , breezeway, backyard ) . Industry and material innovations from the 19th century onwards provide distinctive new words, phrases, and idioms through railroading (see further at rail terminology ) and transportation terminology, ranging from types of roads ( dirt roads , freeways ) to infrastructure ( parking lot , overpass , rest area ), to automotive terminology often now standard in English internationally. Already existing English words—such as store , shop , lumber —underwent shifts in meaning; others remained in
7497-546: The 20th century. The use of English in the United States is a result of British colonization of the Americas . The first wave of English-speaking settlers arrived in North America during the early 17th century, followed by further migrations in the 18th and 19th centuries. During the 17th and 18th centuries, dialects from many different regions of England and the British Isles existed in every American colony, allowing
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#17327753890597644-467: The African continent, so are transmitted by different species. This table summarizes this information: Human African trypanosomiasis, also called sleeping sickness , is caused by trypanosomes of the species Trypanosoma brucei . This disease is invariably fatal if left untreated, but can almost always be cured with current medicines if the disease is diagnosed early enough. Sleeping sickness begins with
7791-627: The British form is a back-formation , such as AmE burglarize and BrE burgle (from burglar ). However, while individuals usually use one or the other, both forms will be widely understood and mostly used alongside each other within the two systems. While written American English is largely standardized across the country and spoken American English dialects are highly mutually intelligible, there are still several recognizable regional and ethnic accents and lexical distinctions. The regional sounds of present-day American English are reportedly engaged in
7938-413: The East Coast (perhaps in imitation of 19th-century London speech), even the East Coast has gradually begun to restore rhoticity, due to it becoming nationally prestigious in the 20th century. The pronunciation of ⟨r⟩ is a postalveolar approximant [ ɹ̠ ] or retroflex approximant [ ɻ ] , but a unique "bunched tongue" variant of the approximant r sound
8085-571: The Inland North. Rather than one particular accent, General American is best defined as an umbrella covering an American accent that does not incorporate features associated with some particular region, ethnicity, or socioeconomic group. Typical General American features include rhoticity , the father–bother merger , Mary–marry–merry merger , pre-nasal "short a " tensing , and other particular vowel sounds . General American features are embraced most by Americans who are highly educated or in
8232-573: The South), sneakers for athletic shoes (but often tennis shoes outside the Northeast), and shopping cart for a cart used for carrying supermarket goods. American English and British English (BrE) often differ at the levels of phonology, phonetics, vocabulary, and, to a much lesser extent, grammar and orthography. The first large American dictionary, An American Dictionary of the English Language , known as Webster's Dictionary ,
8379-528: The U.S. Several verbs ending in -ize are of U.S. origin; for example, fetishize, prioritize, burglarize, accessorize, weatherize , etc.; and so are some back-formations (locate, fine-tune, curate, donate, emote, upholster and enthuse). Among syntactic constructions that arose are outside of, headed for, meet up with, back of, etc. Americanisms formed by alteration of some existing words include notably pesky, phony, rambunctious, buddy, sundae , skeeter, sashay and kitty-corner. Adjectives that arose in
8526-570: The U.S. are for instance foothill , landslide (in all senses), backdrop , teenager , brainstorm , bandwagon , hitchhike , smalltime, and a huge number of others. Other compound words have been founded based on industrialization and the wave of the automobile: five-passenger car, four-door sedan, two-door sedan, and station-wagon (called an estate car in British English). Some are euphemistic ( human resources , affirmative action , correctional facility ). Many compound nouns have
8673-676: The U.S. are, for example, lengthy, bossy, cute and cutesy, punk (in all senses), sticky (of the weather), through (as in "finished"), and many colloquial forms such as peppy or wacky . A number of words and meanings that originated in Middle English or Early Modern English and that have been in everyday use in the United States have since disappeared in most varieties of British English; some of these have cognates in Lowland Scots . Terms such as fall ("autumn"), faucet ("tap"), diaper ("nappy"; itself unused in
8820-530: The U.S. while changing in Britain. Science, urbanization, and democracy have been important factors in bringing about changes in the written and spoken language of the United States. From the world of business and finance came new terms ( merger , downsize , bottom line ), from sports and gambling terminology came, specific jargon aside, common everyday American idioms, including many idioms related to baseball . The names of some American inventions remained largely confined to North America ( elevator [except in
8967-427: The U.S.), candy ("sweets"), skillet , eyeglasses , and obligate are often regarded as Americanisms. Fall for example came to denote the season in 16th century England, a contraction of Middle English expressions like "fall of the leaf" and "fall of the year." Gotten ( past participle of get ) is often considered to be largely an Americanism. Other words and meanings were brought back to Britain from
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#17327753890599114-597: The U.S., especially in the second half of the 20th century; these include hire ("to employ"), I guess (famously criticized by H. W. Fowler ), baggage , hit (a place), and the adverbs overly and presently ("currently"). Some of these, for example, monkey wrench and wastebasket , originated in 19th century Britain. The adjectives mad meaning "angry", smart meaning "intelligent", and sick meaning "ill" are also more frequent in American (and Irish) English than British English. Linguist Bert Vaux created
9261-538: The United States and the United Kingdom suggest that, while spoken American English deviated away from period British English in many ways, it is conservative in a few other ways, preserving certain features 21st-century British English has since lost. Full rhoticity (or "R-fulness") is typical of American accents, pronouncing the phoneme /r/ (corresponding to the letter ⟨r⟩ ) in all environments, including in syllable-final position or before
9408-605: The West and Midwest, and New York Latino English , spoken in the New York metropolitan area . Additionally, ethnic varieties such as Yeshiva English and " Yinglish " are spoken by some American Orthodox Jews , Cajun Vernacular English by some Cajuns in southern Louisiana , and Pennsylvania Dutch English by some Pennsylvania Dutch people. American Indian Englishes have been documented among diverse Indian tribes. The island state of Hawaii , though primarily English-speaking,
9555-464: The ability to acquire information from two non-parallel planes and allows sensation of rotation in all three directions. However, flies are most sensitive to pitch. When halteres are experimentally induced to flap, volleys of action potentials within the haltere nerve occur in synchrony with the haltere-beat frequency. When flies are then rotated, these volleys break down, likely in response to different groups of sensilla being activated to inform
9702-401: The above figure (Directions of rotation). The mechanoreceptors at the base of the halteres are only able to measure force in two directions (horizontal and vertical), so a single haltere is only able to measure rotations along two of the three axes. Because the halteres are set at different angles (90-degree offset), they also beat along two separate horizontal and vertical axes. This gives them
9849-555: The accents spoken in the " Midland ": a vast band of the country that constitutes an intermediate dialect region between the traditional North and South. Western U.S. accents mostly fall under the General American spectrum. Below, ten major American English accents are defined by their particular combinations of certain vowel sounds: In 2010, William Labov noted that Great Lakes, Philadelphia, Pittsburgh, and West Coast accents have undergone "vigorous new sound changes" since
9996-505: The aeronautical sense ], gasoline ) as did certain automotive terms ( truck , trunk ). New foreign loanwords came with 19th and early 20th century European immigration to the U.S.; notably, from Yiddish ( chutzpah , schmooze, bupkis, glitch ) and German ( hamburger , wiener ). A large number of English colloquialisms from various periods are American in origin; some have lost their American flavor (from OK and cool to nerd and 24/7 ), while others have not ( have
10143-405: The anatomy of dipteran flies. Most tsetse flies are, physically, very tough. Houseflies, and even horseflies, are easily killed with a flyswatter, for example; a great deal of effort is needed to crush a tsetse fly. Tsetse has an unusual life cycle , which may be due to the richness of their blood food source. A female fertilizes only one egg at a time; she will retain each egg within her uterus,
10290-427: The angle created between their fingertips and spine was 90 degrees, this would be a 90-degree offset. The halteres of flies work the same way. They are positioned behind their bodies, forming a 90-degree angle between the haltere bulbs and the center of their thorax. It is necessary for the halteres to be positioned like this in order to detect the three axes of motion. Those axes are yaw, pitch and roll, as illustrated in
10437-534: The arrangement of sensory organs known as campaniform sensilla , found at the base of the haltere, show many similarities to those found at the base of the hindwings in other insects. The sensilla are arranged in a way so similar to that of hindwings, that were the halteres to be replaced with wings, the forces produced would still be sufficient to activate the same sensory organs. Genetic studies have also brought to light many similarities between halteres and hindwings. In fact, haltere development has been traced back to
10584-423: The base of each haltere detect the different directions of rotation, which also explains why flies with one haltere are still able to fly without issue. It is generally accepted that the halteres evolved from the non-flight wings of insects – the hind-wings of Diptera and the fore wings of Strepsiptera respectively. Their movement, structure, function and development all support this hypothesis. Characterizations of
10731-567: The base of the halteres. Using functional morphology and behavior studies, Pix et al. showed that these sensors then transmit body position information to the head and abdomen to produce compensatory movements. For simplicity, the remainder of this article will refer only to dipteran halteres. Certain lepidopterans (moths and butterflies) exhibit small amplitude oscillation of their antennae at constant angles during flight. Antennal movements in lepidopterans were originally hypothesized to aid in wind or gravity perception. A study performed using
10878-639: The base) the fly's ability to perceive roll movements at high angular velocities disappeared. Halteres and vision both play a role in stabilizing the head. Flies are also able to perform compensatory head movements to stabilize their vision without the use of their halteres. When the visual field is artificially rotated around a fly at slower angular velocities, head stabilization still occurs. Head stabilization outputs due to optical inputs alone are slower to respond, but also last longer than those due to haltere inputs. From this result it can be concluded that although halteres are required for detecting fast rotations,
11025-443: The club-like form of halteres. Though strepsipterans are very difficult to locate and are additionally rather short-lived, Pix et al. (1993) confirmed that the specialized forewings that male Strepsiptera possess perform the same function as dipteran halteres. Rotational movements of the body combined with the oscillating halteres produce Coriolis forces that can be detected by fields of mechanosensors (campaniform sensilla) located at
11172-406: The country), though the vowel-consonant cluster found in "bird", "work", "hurt", "learn", etc. usually retains its r pronunciation, even in these non-rhotic American accents. Non-rhoticity among such speakers is presumed to have arisen from their upper classes' close historical contact with England, imitating London's r -dropping, a feature that has continued to gain prestige throughout England from
11319-424: The diameter of the haltere bulb. An extreme example of this trait is in the family Syrphidae (hoverflies), where the bulb of the haltere is positioned nearly perpendicular to the stalk. Flies typically hold their halteres at a 90-degree offset. To visualize this, if you were to imagine a person holding their arms out sideways, this would be a 180-degree offset. If that person then moved their arms backward so that
11466-470: The difference in length is what is detected and transformed into electrical signaling. There are far fewer chordotonal organs at the base of the haltere than campaniform sensilla (on the order of hundreds), so it is assumed that they are far less important for detecting and transmitting rotational information from haltere movements. Insect eyes are unable to move independently of the head. In order for flies to stabilize their visual fields , they must adjust
11613-414: The disease in animals is similar to the course of sleeping sickness in humans. Trypanosoma congolense and Trypanosoma vivax are the two most important species infecting bovine cattle in sub-Saharan Africa . Trypanosoma simiae causes a virulent disease in swine . American English American English , sometimes called United States English or U.S. English , is the set of varieties of
11760-420: The disease, has often been subdivided into three subspecies that were identified based either on the vertebrate hosts which the strain could infect or on the virulence of the disease in humans. The trypanosomes infectious to animals and not to humans were named Trypanosoma brucei brucei . Strains that infected humans were divided into two subspecies based on their different virulences: Trypanosoma brucei gambiense
11907-614: The diverse regional dialects of British English) became common after the mid-18th century, while at the same time speakers' identification with this new variety increased. Since the 18th century, American English has developed into some new varieties, including regional dialects that retain minor influences from waves of immigrant speakers of diverse languages, primarily European languages. Some racial and regional variation in American English reflects these groups' geographic settlement, their de jure or de facto segregation, and patterns in their resettlement. This can be seen, for example, in
12054-742: The double quotation mark ("like this") over the single ('as here'). Vocabulary differences vary by region. For example, autumn is used more commonly in the United Kingdom, whereas fall is more common in American English. Some other differences include: aerial (United Kingdom) vs. antenna, biscuit (United Kingdom) vs. cookie/cracker, car park (United Kingdom) vs. parking lot, caravan (United Kingdom) vs. trailer, city centre (United Kingdom) vs. downtown, flat (United Kingdom) vs. apartment, fringe (United Kingdom) vs. bangs, and holiday (United Kingdom) vs. vacation. AmE sometimes favors words that are morphologically more complex, whereas BrE uses clipped forms, such as AmE transportation and BrE transport or where
12201-487: The egg; following egg development and birth is the three larval stages, a pupal stage, and the emergence and maturation of the adult. Overall Suidae are the most important hosts. Waterbuck ( Kobus ellipsiprymnus ) are unmolested by Glossina because they produce volatiles which act as repellents . Waterbuck odor volatiles are under testing and development as repellents to protect livestock . By species, bloodmeals are derived from: The genome of Glossina morsitans
12348-536: The elucidation of the strains of T. brucei infective to humans requires a more complex explanation. Procyclins are proteins developed in the surface coating of trypanosomes whilst in their tsetse fly vector. Other forms of human trypanosomiasis also exist but are not transmitted by tsetse. The most notable is American trypanosomiasis, known as Chagas disease , which occurs in South America , caused by Trypanosoma cruzi , and transmitted by certain insects of
12495-448: The end of the pupal stage, tsetse emerges as adult flies. The adults are relatively large flies, with lengths of 0.5–1.5 centimetres ( 1 ⁄ 4 – 5 ⁄ 8 in), and have a recognizable shape, or bauplan , which makes them easy to distinguish from other flies. Tsetse have large heads, distinctly separated eyes, and unusual antennae. The thorax is quite large, while the abdomen is wider, rather than elongated, and shorter than
12642-409: The feeding time, promoting trypanosome transmission to the vertebrate host. These trypanosomes are highly evolved and have developed a life cycle that requires periods in both the vertebrate and tsetse hosts. Tsetse transmit trypanosomes in two ways, mechanical and biological transmission. The relative importance of these two modes of transmission for the propagation of tsetse-vectored trypanosomiases
12789-399: The few genera having relatively reliable information available: Moloo and Kutuza 1970 for G. brevipalpis (including its innervation) and Langley 1965 for G. morsitans . The reproductive tract of adult females includes a uterus , which can become large enough to hold the third-instar larva at the end of each pregnancy . The article " Parasitic flies of domestic animals " has a diagram of
12936-417: The flies can be raised in a laboratory, and because they are relatively large, facilitating their analysis. Tsetse flies can be seen as independent individuals in three forms: as third- instar larvae, pupae, and adults. Tsetse first becomes separate from their mothers during the third larval instar, during which they have the typical appearance of maggots . However, this life stage is short, lasting at most
13083-444: The flies to detect a wide range of angular velocities in all three directions of rotation. Two main aspects of the visual field have been used to study fly vision, figure and background . Figures are the objects that the fly is focused on and background represents everything else. When haltere bulbs are removed from tethered flying flies, they are still able to track moving figures, but they struggle to stabilize moving backgrounds. If
13230-458: The fly of its recently changed body position. Haltere afferents have also been shown to terminate in the mesothoracic neuropil where flight muscle neurons are located. Haltere afferent activity responding to rotations and wing steering behavior converge in this processing region. Sensory inputs from five sensory fields located at the base of the haltere all converge onto one nerve, the haltere nerve. How these sensory fields are organized at
13377-517: The following two centuries) when this ethnic group eventually made up one-seventh of the colonial population. Scotch-Irish settlers spread from Delaware and Pennsylvania throughout the larger Mid-Atlantic region, the inland regions of both the South and North, and throughout the West: American dialect areas that were all uninfluenced by upper-class non-rhoticity and that consequently have remained consistently rhotic. While non-rhoticity spread on
13524-478: The genus Trypanosoma . These organisms are about the size of red blood cells. Different species of trypanosomes infect different hosts. They range widely in their effects on the vertebrate hosts. Some species, such as T. theileri , do not seem to cause any health problems except perhaps in animals that are already sick. Some strains are much more virulent . Infected flies have an altered salivary composition which lowers feeding efficiency and consequently increases
13671-429: The haltere bulbs to be much further from the body and easily visible to the naked eye. More derived families, such as Calliphoridae (blow flies), have developed specialized structures called "calyptrae" or "squama", which are tiny flaps of wing, that cover the haltere. Pringle (1948) hypothesized that they prevented wind turbulence from affecting haltere movements, allowing more precise detection of body position, but this
13818-430: The haltere is no longer moving in only two directions (up and down), but four (up, down, left, and right). The force exerted on the halteres in response to this left right movement is known as Coriolis force and can be produced when any moving object is rotated in the three directions of rotation , yaw, pitch or roll (see figure). When this occurs, tiny bell-shaped structures at the base of the haltere experience strain as
13965-439: The haltere nerve and a wing steering motor neuron known as mnb1. Flies use indirect flight muscles to accomplish wing movement, and the beating haltere movements are driven by the same group of muscles (see dynamics section). In addition to the indirect flight muscles which are responsible for the flapping motion, there are also steering muscle which control the rotation/angle of the wings. Because halteres evolved from hindwings,
14112-553: The haltere stalk bends in their direction. The nervous system can then transform the bending of these hairs into electrical signals, which the fly interprets as body rotation information. The fly uses this information to make corrections to its position and thereby restabilizes itself during flight. Further details explaining the dynamics and physiology of halteres are described below. Halteres are typically only associated with flight stabilization, but their ability to detect body rotations can elicit compensatory reactions not only from
14259-470: The halteres are removed, these insects perform more poorly at certain walking challenges. However, how haltere information is processed and used during walking remains, with few exceptions, unclear. Specific examples of what has been found are described below. Halteres were first documented by William Derham in 1714. He discovered that flies were unable to remain airborne when their halteres were surgically removed, but otherwise behaved normally. This result
14406-408: The halteres would stimulate the central nervous system into a state of activity which allowed the wings to produce flight behavior. It has since been concluded that this is not in fact true, and that the original assertion that halteres act as balance organs is the correct one. V. Buddenbrock was able to show that immediately after haltere removal flies were unable to produce normal wing movements. This
14553-400: The hawk moth, Manduca sexta , confirmed that these tiny, antennal oscillations were actually contributing to body rotation sensation. Sane et al. (2007) determined that antennae were responsible for flight stabilization in hawk moths by removing the long part of the antenna (the flagellum), then reattaching it to determine its influence on flight performance. When the flagella were removed,
14700-944: The hospital , BrE to hospital ; contrast, however, AmE actress Elizabeth Taylor , BrE the actress Elizabeth Taylor ). Often, these differences are a matter of relative preferences rather than absolute rules; and most are not stable since the two varieties are constantly influencing each other, and American English is not a standardized set of dialects. Differences in orthography are also minor. The main differences are that American English usually uses spellings such as flavor for British flavour , fiber for fibre , defense for defence , analyze for analyse , license for licence , catalog for catalogue and traveling for travelling . Noah Webster popularized such spellings in America, but he did not invent most of them. Rather, "he chose already existing options on such grounds as simplicity, analogy or etymology." Other differences are due to
14847-674: The influence of 18th-century Protestant Ulster Scots immigrants (known in the U.S. as the Scotch-Irish ) in Appalachia developing Appalachian English and the 20th-century Great Migration bringing African-American Vernacular English to the Great Lakes urban centers. Any phonologically unmarked North American accent falls under an umbrella known as General American. This section mostly refers to such General American features. Studies on historical usage of English in both
14994-416: The large order Diptera (flies) have halteres which evolved from a pair of ancestral hindwings , while males of the much smaller order Strepsiptera (stylops) have halteres which evolved from a pair of ancestral forewings . Halteres oscillate rapidly along with the wings and operate like vibrating structure gyroscopes : any rotation of the plane of oscillation causes a force on the vibrating halteres by
15141-438: The late 18th century onwards, but which has conversely lost prestige in the U.S. since at least the early 20th century. Non-rhoticity makes a word like car sound like cah or source like sauce . New York City and Southern accents are the most prominent regional accents of the country, as well as the most stigmatized and socially disfavored. Southern speech, strongest in southern Appalachia and certain areas of Texas,
15288-482: The left and right haltere muscles. Although halteres are always synchronized with the movements of the wings, the phase at which they oscillate differs between species. Brachyceran flies (short-antennaed) oscillate their halteres almost exactly opposite their wings (180 degrees). More ancient suborders such as the Nematecerans (long-antennaed flies), which for example include crane flies and mosquitoes, exhibit
15435-520: The level of the central nervous system is currently unknown. It has been determined that those five sensory fields all project to the thorax in a "region-specific" way and afferents originating from the forewing were also shown to converge in the same regions. Not every specific target for the haltere afferents have been determined, but a few connections between motor neurons known to be involved in wing steering control and particular haltere sensory fields have been identified, particularly one synapse between
15582-494: The lobes of the crop of G. m. centralis and G. m. morsitans . Tsetse are in the order Diptera , the true flies. They belong to the superfamily Hippoboscoidea, in which the tsetse's family, the Glossinidae, is one of four families of blood-feeding obligate parasites. Up to 34 species and subspecies of tsetse flies are recognized, depending on the particular classification used. All current classifications place all
15729-443: The majority of other insect orders use what are known as indirect flight muscles to accomplish flight. Indirect insect flight muscles are composed of two sets of perpendicular muscles (see left figure) that are attached to the thorax (instead of directly to the wing base as is the case for direct flight muscles). When the first set of muscles contracts, they deform the body of the insect and compress its thorax vertically, which lifts
15876-427: The mid-nineteenth century onwards, so they "are now more different from each other than they were 50 or 100 years ago", while other accents, like of New York City and Boston, have remained stable in that same time-frame. However, a General American sound system also has some debated degree of influence nationwide, for example, gradually beginning to oust the regional accent in urban areas of the South and at least some in
16023-617: The most formal contexts, and regional accents with the most General American native features include North Midland, Western New England, and Western accents. Although no longer region-specific, African-American Vernacular English , which remains the native variety of most working- and middle-class African Americans , has a close relationship to Southern dialects and has greatly influenced everyday speech of many Americans, including hip hop culture . Hispanic and Latino Americans have also developed native-speaker varieties of English. The best-studied Latino Englishes are Chicano English , spoken in
16170-553: The moths were no longer able to maintain stable flight. After reattachment of the flagella, flight performance was restored. The source of this difference was determined to be mechanosensory. There are two sets of mechanosensory organs located at the base of the lepidopteran antenna, Böhm's bristles and the Johnston organ. These fields of receptors respond to different directions of antennal movements. Antennae are also capable of sensing odor, humidity, and temperature. Sane et al. (2007)
16317-411: The movement of wings was still coupled with the movement of halteres. When a forcep was used to manually move a wing up and down, not only did the opposite wing move in synchrony, the halteres also beat in antiphase with both wings. The source of this coupling however, was not between the muscles which control the halteres and those that control the wings. Instead, two small ridges of cuticle known as
16464-572: The observed physiological changes. Instead, he suggested that Ubx -regulated target gene sets were the direct source of the observed changes. Several Ubx -regulated target genes have been identified, including two direct targets, spalt and knot , which are expressed in the wing and repressed in halteres, and which are not affected by extradenticle . Other genes which are expressed in wings and repressed in halteres have also been identified, but whether or not they act as direct targets of Ubx regulation are still unknown. Dipteran insects along with
16611-409: The offspring developing internally (during the first three larval stages ), in an adaptation called adenotrophic viviparity . During this time, the female feeds the developing offspring with a milky substance (secreted by a modified gland) in the uterus. In the third larval stage, the tsetse larvae leave the uterus and begin an independent life. The newly-birthed larvae crawl into the ground and develop
16758-482: The order Diptera and again in Strepsiptera . Another structure in the class insecta also exists whose primary function is not the same as halteres, but that additionally serves a similar balancing function. This occurs in the order Lepidoptera and refers to the antennae of moths and butterflies. Strepsipterans are a unique group of insects with major sexual dimorphism. The females spend their entire lives in
16905-521: The other); Secondly, tsetse also have a long proboscis , extending directly forward, which is attached by a distinct bulb to the bottom of their heads. Fossilized tsetse has been recovered from Paleogene -aged rocks in the United States and Germany. Twenty-three extant species of tsetse flies are known from the African continent as well as the Arabian Peninsula. Tsetse without the "fly" has become more common in English , particularly in
17052-402: The past forms of a few verbs (for example, AmE/BrE: learned / learnt , burned / burnt , snuck/sneaked , dove/dived ) although the purportedly "British" forms can occasionally be seen in American English writing as well; different prepositions and adverbs in certain contexts (for example, AmE in school, BrE at school ); and whether or not a definite article is used, in very few cases (AmE to
17199-430: The position of their entire head. Sensory inputs detected by halteres not only determine the position of the body, but also, the position of the head, which can move independently from the body. Halteres are particularly useful for detecting fast perturbations during flight and only respond to angular velocities (speeds of rotation) above a certain threshold. When flies are focused on an object in front of them and their body
17346-430: The reason/a reason for the behavioral changes seen, especially the unnecessarily increased feeding frequency, which increases transmission opportunities. This may be due in part to the altered glucose metabolism observed, causing a perceived need for more calories. (The metabolic change, in turn, being due to complete absence of glucose-6-phosphate 1-dehydrogenase in infected flies.) Monoamine neurotransmitter synthesis
17493-444: The responsiveness of the halteres and eyes are tuned to complementary speeds of rotation. Responses to body rotations detected via the visual system are greatest at slow speeds and decrease with increased angular velocity. In contrast, body rotations detected by the halteres elicit the greatest responses at higher angular velocities and degrade as the speed of rotation decreases. The integration of these two separately tuned sensors allows
17640-406: The right. Unfortunately, as soon as it does, the halteres sense a body rotation and reflexively correct the turn, preventing the fly from changing direction. Chan and Dickinson (1998) suggested that what the fly does to prevent this from occurring is to first move its halteres as if it were being pushed in the opposite direction that it wants to go. The fly has not moved, but the halteres have sensed
17787-407: The same complement of steering muscles exists for the other directions of movement as well. Chan et al. (1998) identified 10 direct control muscles in the haltere similar to those found in the forewing. In 1998, Chan and Dickinson proposed that the planned haltere movements (without external forces acting on them) were what initiated planned turns. To explain this, imagine a fly that wishes to turn to
17934-401: The same on the left and right side. This is what allows the flies to turn and is accomplished using a gearbox , much like what you would find in an automobile. This gearbox can change the maximum amplitude of the wing movement and determine its speed of motion. The wings of flies even have a clutch structure at their base. The clutch moves between grooves in the gearbox, to engage and disengage
18081-558: The scientific and development communities. The word is pronounced tseh-tseh in the Sotho languages and is easily rendered in other African languages. During World War II, a British de Havilland antisubmarine aircraft was known as the Tsetse Mosquito . The biology of tsetse is relatively well understood by entomologists . They have been extensively studied because of their medical, veterinary, and economic importance, because
18228-402: The subepimeral ridges were found to be responsible. These ridges connect the right wing to the right haltere and the left wing to the left haltere. Each side of the body must be synchronized and the two sides are also coupled. That is, the left and right wings and thus the left and right halteres always beat at the same frequency. However, the amplitude of the wingbeat does not always have to be
18375-446: The surface of the exoskeleton (cuticle) of insects. Attached inside the cap is the tip of a dendritic projection (or sensory nerve fiber). The outer segment of the dendritic projection is attached to the inside surface of the cap. When the haltere is pushed to one side, the cuticle of the insect bends and the surface of the cap is distorted. The inner dendrite is able to detect this distortion and convert it to an electrical signal which
18522-421: The thorax, as are two wings and two halteres . The abdomen is short but wide and changes dramatically in volume during feeding. The internal anatomy of the tsetse is fairly typical of the insects ; the crop is large enough to accommodate a huge increase in size during feeding, as tsetse can take a blood meal equal in weight to themselves. The dipteran crop is heavily understudied, with Glossina being one of
18669-570: The traditional standard accent of (southern) England, Received Pronunciation (RP), has evolved a trap–bath split . Moreover, American accents preserve /h/ at the start of syllables, while perhaps a majority of the regional dialects of England participate in /h/ dropping , particularly in informal contexts. However, General American is also innovative in a number of its own ways: The process of coining new lexical items started as soon as English-speaking British-American colonists began borrowing names for unfamiliar flora, fauna, and topography from
18816-775: The tsetse species in a single genus named Glossina . Most classifications place this genus as the sole member of the family Glossinidae. The Glossinidae are generally placed within the superfamily Hippoboscoidea , which contains other hematophagous families. The tsetse genus is generally split into three groups of species based on a combination of distributional, ecological, behavioral, molecular and morphological characteristics. The genus includes; savannah flies, forest flies and riverine and lacustrine flies. The 'savannah' flies: ( Morsitans group , subgenus Glossina s.s.): The 'forest' flies: ( Fusca group, subgenus Austenina ): The 'riverine' and 'lacustrine' flies: ( Palpalis group, subgenus Nemorhina ): Fossil glossinids are known from
18963-417: The verb-and-preposition combination: stopover, lineup, tryout, spin-off, shootout , holdup, hideout, comeback, makeover , and many more. Some prepositional and phrasal verbs are in fact of American origin ( win out, hold up, back up/off/down/out, face up to and many others). Noun endings such as -ee (retiree), -ery (bakery), -ster (gangster) and -cian (beautician) are also particularly productive in
19110-519: The very southwest of Saudi Arabia. Although Carter found G. tachiniodes in 1903 nearby, near Aden in southern Yemen, there have been no confirmations since. Tsetse are biological vectors of trypanosomes , meaning that in the process of feeding, they acquire and then transmit small, single-celled trypanosomes from infected vertebrate hosts to uninfected animals. Some tsetse-transmitted trypanosome species cause trypanosomiasis , an infectious disease. In humans, tsetse transmitted trypanosomiasis
19257-486: The visual system is adept by itself at sensing and correcting for slower body movements. Thus, the visual and mechanosensory (halteres) systems work together to stabilize the visual field of the animal: first, by quickly responding to fast changes (halteres), and second, by maintaining that response until it is corrected (vision). Flies rely on both visual information from their compound eyes and mechanical input from their halteres. Sherman and Dickinson (2002) discovered that
19404-471: The way a heavy basket below a hot air balloon prevents the balloon from tipping), which supported the hypothesis that halteres are responsible for sensing body rotations. The original balancer theory, which was postulated by Pringle (1948), only accounted for forces produced in two directions. Pringle claimed that yaw was the only direction of rotation that flies used their halteres to detect. Using high speed video analysis, Faust (1952) demonstrated that this
19551-448: The wing muscles and also modulate the wingbeat amplitude. When the amplitude of the left wing is less than the right, the fly will make a left turn. Even though haltere movement is controlled by separate muscles than the wings, because the wings are mechanically coupled with the halteres, changes in wingbeat frequency extend to the haltere-beat frequency as well, but haltere beat amplitude does not change. Although halteres are coupled with
19698-400: The wing steering muscles, but also from neck muscles which are responsible for head position and gaze. Halteres may also be useful for other behaviors. Certain species of flies have been observed to oscillate their halteres while walking in addition to oscillating them during flight. In these individuals, halteres could thus be detecting sensory information during walking behavior as well. When
19845-511: The wings and with each other during flight, some flies oscillate their halteres while walking (without oscillating their wings). Because the haltere muscles are tiny in comparison to the flight muscles, flight muscle activity completely overshadows that of the haltere muscles during flight. It is unknown how haltere muscle activity during flight differs from walking. The left and right halteres show much more variable phase relationships while walking compared with flying, which may indicate decoupling of
19992-464: The wings. Four characteristics collectively separate adult tsetse from other kinds of flies: Like all other insects , tsetse flies have an adult body comprising three visibly distinct parts: the head, the thorax, and the abdomen. The head has large eyes, distinctly separated on each side, and a distinct, forward-pointing proboscis attached underneath by a large bulb. The thorax is large, made of three fused segments. Three pairs of legs are attached to
20139-435: The wings. When the first set of muscles relaxes and the second set contracts, the thorax is squeezed in the opposite direction, which extends the body vertically and moves the wings downward. The below figure demonstrates this movement with only the first set of muscles. The movement of the wings and the halteres are mechanically coupled. Sane et al. (2015) demonstrated that in freshly killed flies, without any neural input,
20286-775: The word corn , used in England to refer to wheat (or any cereal), came to denote the maize plant, the most important crop in the U.S. Most Mexican Spanish contributions came after the War of 1812 , with the opening of the West, like ranch (now a common house style ). Due to Mexican culinary influence, many Spanish words are incorporated in general use when talking about certain popular dishes: cilantro (instead of coriander), queso, tacos, quesadillas, enchiladas, tostadas, fajitas, burritos, and guacamole. These words usually lack an English equivalent and are found in popular restaurants. New forms of dwelling created new terms ( lot , waterfront) and types of homes like log cabin , adobe in
20433-609: The world. Any American or Canadian accent perceived as lacking noticeably local, ethnic, or cultural markers is known in linguistics as General American ; it covers a fairly uniform accent continuum native to certain regions of the U.S. but especially associated with broadcast mass media and highly educated speech. However, historical and present linguistic evidence does not support the notion of there being one single mainstream American accent . The sound of American English continues to evolve, with some local accents disappearing, but several larger regional accents having emerged in
20580-541: Was able to demonstrate that it was the mechanosensors that were responsible for flight stability as opposed to the other sensory organs, because when the flagella were removed and then reattached, all antennal nerves were severed excluding those at the base (Böhm's bristles and the Johnston organ). In segmented organisms there are genes called Hox genes , which determine the development of serial homologs , or repeating structures within an organism (e.g. jointed appendages of arthropods or vertebrae in mammals ). In insects,
20727-463: Was initially attributed to the haltere's ability to sense and maintain equilibrium. In 1917 v. Buddenbrock asserted that something else was responsible for the flies' loss of flight ability. He claimed that the halteres should instead be considered "stimulation organs". In other words, that the activity of the halteres energized the wing muscular system, so that they acted as an on/off switch for flight. V. Buddenbrock attempted to show that activation of
20874-428: Was later explained by the fact that allowing flies a few minutes recovery time post-surgery resulted in total recovery of normal flight muscle control. Further, in an interesting side experiment performed by Pringle (1938), when a thread was attached to the abdomen of haltereless flies, relatively stable flight was again achieved. The thread in these experiments presumably aided in keeping the fly from rotating (similar to
21021-401: Was never tested. The stalk of the haltere is also not always straight. Instead, the stalk's shape in more derived families tends to be reflective of the body shape of the individual. This minimizes the amount of air space between end-knobs and the sides of the abdomen and thorax. In these families, the halteres beat so close to the body that the distance between haltere and thorax is a fraction of
21168-483: Was not the case and that halteres are capable of detecting all three directions of rotation. In response to this new discovery, Pringle reexamined his previous assumption and came to the conclusion that flies were capable of detecting all three directions of rotation simply by comparing inputs from the left and right sides of the body. Of course, this is not the actual mechanism by which flies detect rotation. Different fields of sensory organs located in different regions at
21315-410: Was sequenced in 2014. Tsetse flies have at least three bacterial symbionts . The primary symbiont is Wigglesworthia ( Wigglesworthia glossinidia ), which live within the fly's bacteriocytes . The second symbiont is Sodalis ( Sodalis glossinidius ) intercellularly or intracellularly, and the third is some kind of Wolbachia . The salivary gland hypertrophy virus causes abnormal bleeding in
21462-427: Was thought to have a slower onset and Trypanosoma brucei rhodesiense refers to strains with a more rapid, virulent onset. This characterization has always been problematic but was the best that could be done given the knowledge of the time and the tools available for identification. A recent molecular study using restriction fragment length polymorphism analysis suggests that the three subspecies are polyphyletic , so
21609-469: Was written by Noah Webster in 1828, codifying several of these spellings. Differences in grammar are relatively minor, and do not normally affect mutual intelligibility; these include: typically a lack of differentiation between adjectives and adverbs, employing the equivalent adjectives as adverbs he ran quick / he ran quickly ; different use of some auxiliary verbs ; formal (rather than notional) agreement with collective nouns ; different preferences for
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