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Horseshoe bat

Horseshoe bats are bats in the family Rhinolophidae. In addition to the single living genus, Rhinolophus, which has about 106 species, the extinct genus Palaeonycteris has been recognized. Horseshoe bats are closely related to the Old World leaf-nosed bats, family Hipposideridae, which have sometimes been included in Rhinolophidae. The horseshoe bats are divided into six subgenera and many species groups. The most recent common ancestor of all horseshoe bats lived 34–40 million years ago, though it is unclear where the geographic roots of the family are, and attempts to determine its biogeography have been indecisive. Their taxonomy is complex, as genetic evidence shows the likely existence of many cryptic species, as well as species recognized as distinct that may have little genetic divergence from previously recognized taxa. They are found in the Old World, mostly in tropical or subtropical areas, including Africa, Asia, Europe, and Oceania.

Horseshoe bats are considered small or medium-sized microbats, weighing 4–28 g, with forearm lengths of 30–75 mm and combined lengths of head and body of 35–110 mm. The fur, long and smooth in most species, can be reddish-brown, blackish, or bright orange-red. They get their common name from their large nose-leafs, which are shaped like horseshoes. The nose-leafs aid in echolocation; horseshoe bats have highly sophisticated echolocation, using constant frequency calls at high-duty cycles to detect prey in areas of high environmental clutters. They hunt insects and spiders, swooping down on prey from a perch, or gleaning from foliage. Little is known about their mating systems, but at least one species is monogamous, while another is polygynous. Gestation is approximately seven weeks and one offspring is produced at a time. A typical lifespan is six or seven years, but one greater horseshoe bat lived more than thirty years.

Horseshoe bats are relevant to humans in some regions as a source of disease, as food, and for traditional medicine. Several species are the natural reservoirs of various SARS-related coronaviruses, and data strongly suggests they are a reservoir of SARS-CoV, though humans may face more exposure risk from intermediate hosts such as masked palm civets.

They are hunted for food in several regions, particularly sub-Saharan Africa, but also Southeast Asia. Some species or their guano are used in traditional medicine in Nepal, India, Vietnam, and Senegal.

Taxonomic history
Rhinolophus was first described as a genus in 1799 by French naturalist Bernard Germain de Lacépède. Initially, all extant horseshoe bats were in Rhinolophus, as well as the species now in Hipposideros (roundleaf bats). At first, Rhinolophus was within the family Vespertilionidae. In 1825, British zoologist John Edward Gray subdivided Vespertilionidae into subfamilies, including what he called Rhinolophina. English zoologist Thomas Bell is credited as the first to recognize horseshoe bats as a separate family, using Rhinolophidae in 1836. While Bell is sometimes recognized as the authority for Rhinolophidae, the authority is more often given as Gray, 1825. Horseshoe bats are in the superfamily Rhinolophoidea, along with Craseonycteridae, Hipposideridae Megadermatidae, Rhinonycteridae, and Rhinopomatidae.

Attempts were made to divide Rhinolophus into other genera. In 1816, English zoologist William Elford Leach proposed the genus name Phyllorhina; Gray proposed Aquias in 1847 and Phyllotis in 1866; and German naturalist Wilhelm Peters proposed Coelophyllus in 1867. In 1876, Irish zoologist George Edward Dobson returned all Asiatic horseshoe bats to Rhinolophus, additionally proposing the subfamilies Phyllorhininae (for the hipposiderids) and Rhinolophinae. American zoologist Gerrit Smith Miller Jr. further divided the hipposiderids from the horseshoe bats in 1907, recognizing Hipposideridae as a distinct family. Some authors have considered Hipposideros and associated genera as part of Rhinolophidae as recently as the early 2000s, though they are now most often recognized as a separate family. After the split into Rhinolophidae and Hipposideridae, further divisions were proposed for Rhinolophus, with Rhinolphyllotis in 1934 and Rhinomegalophus in 1951, though both additional genera were returned to Rhinolophus.

Danish mammalogist Knud Andersen was the first to propose species groups for Rhinolophus, doing so in 1905. Species groups are a way of clustering species to reflect evolutionary relationships. He recognized six species groups: R. simplex (now R. megaphyllus), R. lepidus, R. midas (now R. hipposideros), R. philippinensis, R. macrotis, and R. arcuatus. The species have been frequently rearranged among the groups as new groups are added, new species are described, and relationships among species are revised. Fifteen species groups were given by Csorba and colleagues in 2003. Various subgenera have been proposed as well, with six listed by Csorba et al. in 2003: Aquias, Phyllorhina, Rhinolophus, Indorhinolophus, Coelophyllus, and Rhinophyllotis. Informally, the rhinolophids can be split into two major clades: the mostly African clade, and the mostly Oriental clade.

Evolutionary history

The most recent common ancestor of Rhinolophus lived an estimated 34–40 million years ago, splitting from the hipposiderid lineage during the Eocene. Fossilized horseshoe bats are known from Europe (early to mid-Miocene, early Oligocene), Australia (Miocene), and Africa (Miocene and late Pliocene). The biogeography of horseshoe bats is poorly understood. Various studies have proposed that the family originated in Europe, Asia, or Africa. A 2010 study supported an Asian or Oriental origin of the family, with rapid evolutionary radiations of the African and Oriental clades during the Oligocene. A 2019 study found that R. xinanzhongguoensis and R. nippon, both Eurasian species, are more closely related to African species than to other Eurasian species, suggesting that rhinolophids may have a complex biogeographical relationship with Asia and the Afrotropics.

A 2016 study using mitochondrial and nuclear DNA placed the horseshoe bats within the Yinpterochiroptera as sister to Hipposideridae.

Rhinolophidae is represented by one extant genus, Rhinolophus. Both the family and the genus are confirmed as monophyletic (containing all descendants of a common ancestor). As of 2019, there were 106 described species in Rhinolophus, making it the second-most speciose genus of bat after Myotis. Rhinolophus may be undersampled in the Afrotropical realm, with one genetic study estimating that there could be up to twelve cryptic species in the region. Additionally, some taxa recognized as full species have been found to have little genetic divergence. Rhinolophus kahuzi may be a synonym for the Ruwenzori horseshoe bat (R. ruwenzorii), and R. gorongosae or R. rhodesiae may be synonyms of the Bushveld horseshoe bat (R. simulator). Additionally, Smithers's horseshoe bat (R. smithersi), Cohen's horseshoe bat (R. cohenae), and the Mount Mabu horseshoe bat (R. mabuensis) all have little genetic divergence from Hildebrandt's horseshoe bat (R. hildebrandtii). Recognizing the former three as full species leaves Hildebrandt's horseshoe bat paraphyletic.

The second genus in Rhinolophidae is the extinct Palaeonycteris, with the type species Palaeonycteris robustus. Palaeonycteris robustus lived during the Lower Miocene and its fossilized remains were found in Saint-Gérand-le-Puy, France.

Appearance
Horseshoe bats are considered small or medium microbats. Individuals have a head and body length ranging 35–110 mm and have forearm lengths of 30–75 mm. One of the smaller species, the lesser horseshoe bat (R. hipposideros), weighs 4–10 g, while one of the larger species, the greater horseshoe bat (R. ferrumequinum), weighs 16.5–28 g. Fur color is highly variable among species, ranging from blackish to reddish brown to bright orange-red. The underparts are paler than the back fur. The majority of species have long, soft fur, but the woolly and lesser woolly horseshoe bats (R. luctus and R. beddomei) are unusual in their very long, woolly fur.

Like most bats, horseshoe bats have two mammary glands on their chests. Adult females additionally have two teat-like projections on their abdomens, called pubic nipples or false nipples, which are not connected to mammary glands. Only a few other bat families have pubic nipples, including Hipposideridae, Craseonycteridae, Megadermatidae, and Rhinopomatidae; they serve as attachment points for their offspring. In a few horseshoe bat species, males have a false nipple in each armpit.

Head and teeth
All horseshoe bats have large, leaf-like protuberances on their noses, which are called nose-leafs. The nose-leafs are important in species identification, and are composed of several parts. The front of the nose-leaf resembles and is called a horseshoe, earning them the common name of "horseshoe bats". The horseshoe is above the upper lip and is thin and flat. The lancet is triangular, pointed, and pocketed, and points up between the bats' eyes. The sella is a flat, ridge-like structure at the center of the nose. It rises from behind the nostrils and points out perpendicular from the head. Their ears are large and leaf-shaped, nearly as broad as they are long, and lack tragi. The antitragi of the ears are conspicuous. Their eyes are very small. The skull always has a rostral inflation, or bony protrusion on the snout. The typical dental formula of a horseshoe bat is, but the middle lower premolars are often missing, as well as the anterior upper premolars (premolars towards the front of the mouth). The young lose their milk teeth while still in utero, with the teeth resorbed into the body. They are born with the four permanent canine teeth erupted, which enables them to cling to their mothers. This is atypical among bat families, as most newborns have at least some milk teeth at birth, which are quickly replaced by the permanent set.

Postcrania
Several bones in its thorax are fused—the presternum, first rib, partial second rib, seventh cervical vertebra, first thoracic vertebra—making a solid ring. This fusion is associated with the ability to echolocate while stationary. Except for the first digit, which has two phalanges, all of their toes have three phalanges. This distinguishes them from hipposiderids, which have two phalanges in all toes. The tail is completely enclosed in the uropatagium (tail membrane), and the trailing edge of the uropatagium has calcars (cartilaginous spurs).

Echolocation and hearing
Horeshoe bats have very small eyes and their field of vision is limited by their large nose-leafs; thus, vision is unlikely to be a very important sense. Instead, they use echolocation to navigate, employing some of the most sophisticated echolocation of any bat group. To echolocate, they produce sound through their nostrils. While some bats use frequency-modulated echolocation, horseshoe bats use constant-frequency echolocation (also known as single-frequency echolocation). They have high duty cycles, meaning that when individuals are calling, they are producing sound more than 30% of the time. The use of high duty, constant-frequency echolocation aids in distinguishing prey items based on size. These echolocation characteristics are typical of bats that search for moving prey items in cluttered environments full of foliage. They echolocate at particularly high frequencies for bats, though not as high as hipposiderids relative to their body sizes, and the majority concentrate most of the echolocation energy into the second harmonic. The king horseshoe bat (R. rex) and the large-eared horseshoe bat (R. philippensis) are examples of outlier species that concentrate energy into the first harmonic rather than the second. Their highly furrowed nose-leafs likely assist in focusing the emission of sound, reducing the effect of environmental clutter. The nose-leaf in general acts like a parabolic reflector, aiming the produced sound while simultaneously shielding the ear from some of it.

Horseshoe bats have sophisticated senses of hearing due to their well-developed cochlea, and are able to detect Doppler-shifted echoes. This allows them to produce and receive sounds simultaneously. Within horseshoe bats, there is a negative relationship between ear length and echolocation frequency: Species with higher echolocation frequencies tend to have shorter ear lengths. During echolocation, the ears can move independently of each other in a "flickering" motion characteristic of the family, while the head simultaneously moves up and down or side to side.

Diet and foraging
Horseshoe bats are insectivorous, though consume other arthropods such as spiders, and employ two main foraging strategies. The first strategy is flying slow and low over the ground, hunting among trees and bushes. Some species who use this strategy are able to hover over prey and glean them from the substrate. The other strategy is known as perch feeding: Individuals roost on feeding perches and wait for prey to fly past, then fly out to capture it. Foraging usually occurs 16.5–19.5 ft above the ground. While vesper bats may catch prey in their uropatagia and transfer it to their mouths, horseshoe bats do not use their uropatagia to catch prey. At least one species, the greater horseshoe bat, has been documented catching prey in the tip of its wing by bending the phalanges around it, then transferring it to its mouth. While a majority of horseshoe bats are nocturnal and hunt at night, Blyth's horseshoe bat (R. lepidus) is known to forage during the daytime on Tioman Island. This is hypothesized as a response to a lack of diurnal avian (day-active bird) predators on the island.

They have especially small and rounded wingtips, low wing loading (meaning they lave large wings relative to body mass), and high camber. These factors give them increased agility, and they are capable of making quick, tight turns at slow speeds. Relative to all bats, horseshoe bat wingspans are typical for their body sizes, and their aspect ratios, which relate wingspan to wing area, are average or lower than average. Some species, like Rüppell's horseshoe bat (R. fumigatus), Hildebrandt's horseshoe bat, Lander's horseshoe bat (R. landeri), and Swinny's horseshoe bat (R. swinnyi), have particularly large total wing area, though most horseshoe bat species have average wing area.

Reproduction and life cycle
The mating systems of horseshoe bats are poorly understood. A review in 2000 noted that only about 4% of species had published information about their mating systems; along with the free-tailed bats (Molossidae), they had received the least attention of any bat family relative to their species diversity. At least one species, the greater horseshoe bat, appears to have a polygynous mating system where males attempt to establish and defend territories, attracting multiple females. Rhinolophus sedulus, however, is among the few species of bat that are believed to be monogamous (only 17 bat species are recognized as such as of 2000). Some species, particularly temperate species, have an annual breeding season in the fall, while other species mate in the spring. Many horseshoe bat species have the adaptation of delayed fertilization through female sperm storage. This is especially common in temperate species. In hibernating species, the sperm storage timing coincides with hibernation. Other species like Lander's horseshoe bat have embryonic diapause, meaning that while fertilization occurs directly following copulation, the zygote does not implant into the uterine wall for an extended period of time. The greater horseshoe bat has the adaptation of delayed embryonic development, meaning that growth of the embryo is conditionally delayed if the female enters torpor. This causes the interval between fertilization and birth to vary between two and three months. Gestation takes approximately seven weeks before a single offspring is born, called a pup. Individuals reach sexual maturity by age two. While lifespans typically do not exceed six or seven years, some individuals may have extraordinarily long lives. A greater horseshoe bat individual was once banded and then rediscovered thirty years later.

Behavior and social systems
Various levels of sociality are seen in horseshoe bats. Some species are solitary, with individuals roosting alone, while others are highly colonial, forming aggregations of thousands of individuals. The majority of species are moderately social. In some species, the sexes segregate annually when females form maternity colonies, though the sexes remain together all year in others. Individuals hunt solitarily. Because their hind limbs are poorly developed, they cannot scuttle on flat surfaces nor climb adeptly like other bats.

Horseshoe bats enter torpor to conserve energy. During torpor, their body temperature drops to as low as 16 C and their metabolic rates slow. Torpor is employed by horseshoe bats in temperate, sub-tropical, and tropical regions. Torpor has a short duration; when torpor is employed consistently for days, weeks, or months, it is known as hibernation. Hibernation is used by horseshoe bats in temperate regions during the winter months.

Predators and parasites
Overall, bats have few natural predators. Horseshoe bat predators include birds in the order Accipitriformes (hawks, eagles, and kites), as well as falcons and owls. Snakes may also prey on some species while they roost in caves, and domestic cats may hunt them as well. A 2019 study near a colony of bats in central Italy found that 30% of examined cat feces contained the remains of greater horseshoe bats.

Horseshoe bats have a variety of internal and external parasites. External parasites (ectoparasites) include mites in the genus Eyndhovenia, "bat flies" of the families Streblidae and Nycteribiidae, ticks of the genus Ixodes, and fleas of the genus Rhinolophopsylla. They are also affected by a variety of internal parasites (endoparasites), including trematodes of the genera Lecithodendrium, Plagiorchis, Prosthodendrium, and cestodes of the genus Potorolepsis.

Range and habitat
Horseshoe bats have a mostly Paleotropical distribution, though some species are in the southern Palearctic realm. They are found in the Old World, including Africa, Australia, Asia, Europe, and Oceania. The greater horseshoe bat has the greatest geographic range of any horseshoe bat, occurring across Europe, North Africa, Japan, China, and southern Asia. Other species are much more restricted, like the Andaman horseshoe bat (R. cognatus), which is only found on the Andaman Islands. They roost in a variety of places, including buildings, caves, tree hollows, and foliage. They occur in both forested and unforested habitat, with the majority of species occurring in tropical or subtropical areas. For the species that hibernate, they select caves with an ambient temperature of approximately 11 C.

Coronaviruses
Horseshoe bats are of particular interest to public health and zoonosis as a source of coronaviruses.

Following the 2002–2004 SARS outbreak, several animal species were examined as possible natural reservoirs of the causative coronavirus, SARS-CoV. From 2003 to 2018, forty-seven SARS-related coronaviruses were detected in horseshoe bats. In 2019, a wet market in Wuhan, China, was linked to the outbreak of SARS-CoV-2. Genetic analyses of SARS-CoV-2 showed that it was highly similar to viruses found in horseshoe bats.

After the SARS outbreak, the least horseshoe bat (R. pusillus) was seropositive, the greater horseshoe bat tested positive for the virus only, and the big-eared horseshoe bat (R. macrotis), Chinese rufous horseshoe bat (R. sinicus), and Pearson's horseshoe bat (R. pearsoni) were both seropositive and tested positive for the virus. The bats' viruses were highly similar to SARS-CoV, with 88–92% similarity. Intraspecies diversity of SARS-like coronaviruses appears to have arisen in Rhinolophus sinicus by homologous recombination. R. sinicus likely harbored the direct ancestor of SARS-CoV in humans. Though horseshoe bats appeared to be the natural reservoir of SARS-related coronaviruses, humans likely became sick through contact with infected masked palm civets, which were identified as intermediate hosts of the virus.

During the period from 2003 to 2018, forty-seven SARS-related coronaviruses were detected in bats, forty-five in horseshoe bats. Thirty SARS-related coronaviruses were from Chinese rufous horseshoe bats, nine from greater horseshoe bats, two from big-eared horseshoe bats, two from the least horseshoe bat, and one each from the intermediate horseshoe bat (R. affinis), Blasius's horseshoe bat (R. blasii), Stoliczka's trident bat (Aselliscus stoliczkanus), and the wrinkle-lipped free-tailed bat (Chaerephon plicata).

In the market in Wuhan where the SARS-CoV-2 was detected, 96% had a similarity to a virus isolated from the intermediate horseshoe bat. Research on the evolutionary origins of SARS-CoV-2 indicates that bats were the natural reservoirs of SARS-CoV-2. It is yet unclear how the virus was transmitted to humans, though an intermediate host may have been involved. It was once believed to be the Sunda pangolin, but a July 2020 publication found no evidence of transmission from pangolins to humans.

Other viruses
They are also associated with viruses like orthoreoviruses, flaviviruses, and hantaviruses. They have tested positive for Mammalian orthoreovirus (MRV), including a type 1 MRV isolated from the lesser horseshoe bat and a type 2 MRV isolated from the least horseshoe bat. The specific MRVs found in horseshoe bats have not been linked to human infection, though humans can become ill through exposure to other MRVs. The rufous horseshoe bat (R. rouxii) has tested seropositive for Kyasanur Forest disease, which is a tick-borne viral hemorrhagic fever known from southern India. Kyasanur Forest disease is transmitted to humans through the bite of infected ticks, and has a mortality rate of 2–10%. Longquan virus, a kind of hantavirus, has been detected in the intermediate horseshoe bat, Chinese rufous horseshoe bat, and the little Japanese horseshoe bat (R. cornutus).

As food and medicine
Microbats are not hunted nearly as intensely as megabats: only 8% of insectivorous species are hunted for food, compared to half of all megabat species in the Old World tropics. Horseshoe bats are hunted for food, particularly in sub-Saharan Africa. Species hunted in Africa include the halcyon horseshoe bat (R. alcyone), Guinean horseshoe bat (R. guineensis), Hill's horseshoe bat (R. hilli), Hills' horseshoe bat (R. hillorum), Maclaud's horseshoe bat (R. maclaudi), the Ruwenzori horseshoe bat, the forest horseshoe bat (R. silvestris), and the Ziama horseshoe bat (R. ziama). In Southeast Asia, Marshall's horseshoe bat (R. marshalli) is consumed in Myanmar and the large rufous horseshoe bat (R. rufus) is consumed in the Philippines.

The Ao Naga people of Northeast India are reported to use the flesh of horseshoe bats to treat asthma. Ecological anthropologist Will Tuladhar-Douglas stated that the Newar people of Nepal "almost certainly" use horseshoe bats, among other species, to prepare Cikā Lāpa Wasa ("bat oil"). Dead bats are rolled up and placed in tightly sealed jars of mustard oil; the oil is ready when it gives off a distinct and unpleasant smell. Traditional medicinal uses of the bat oil include removing "earbugs", reported to be millipedes that crawl into one's ears and gnaw at the brain, possibly a traditional explanation of migraines. It is also used as a purported treatment for baldness and partial paralysis. In Senegal, there are anecdotal reports of horseshoe bats being used in potions to treat mental illness; in Vietnam, a pharmaceutical company reported using 50 t of horseshoe bat guano each year for medicinal uses.

Conservation
As of 2023, the IUCN had evaluated 94 species of horseshoe bat. They have the following IUCN statuses:
 * Critically endangered: 1 species (Hill's horseshoe bat)
 * Endangered: 13 species
 * Vulnerable: 5 species
 * Near threatened: 9 species
 * Least concern: 51 species
 * Data deficient: 15 species

Like all cave-roosting bats, cave-roosting horseshoe bats are vulnerable to disturbance of their cave habitats. Disturbance can include mining bat guano, quarrying limestone, and cave tourism.

title: Horseshoe bat


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Talk:Bucket argument

Link broken
Nothing philosophical here, but the link to Andrew Motte's translation of the Principia doesn't work anymore. The pdf file can be found here, and a streaming version (quicker to load) there. I don't know which one is better ( maybe both : the stream version inside the article and the pdf for download in the references ?), so i haven't changed anything in the article. (Feel free to delete this comment from the talk page once the link is fixed !) — Preceding unsigned comment added by 82.120.215.231 (talk) 09:49, 5 February 2012 (UTC)

Absolute vs Relative
so... is this true then or what? does this prove there is an absolute frame of reference? i have been wondering this since i was like 12 so it would be nice to know why nobody ever discusses it... -plasticlax

It appears that rotation is absolute, but translation is still relative. pstudier 08:12, 2004 Apr 1 (UTC)

(William M. Connolley 21:42, 18 Oct 2004 (UTC)) I think the variant is due to Ernst Mach. But OTOH the variant I'm used to is an otherwise empty universe featuring two spheres joined together by a rope. If you measure the tension in the rope you can find out if they are spinning. Mach's principle says that there is no tension. I think.

 * Einstein's theory of general relativity does not need the assumption of absolute space. Of course, Einsteins theory of gravity and motion does need to provide a mechanism that is telling matter whether it is accelerating or not, the bucket thought experiment proves that.

 * According to the theory of general relativity there is a universal inertial field. This universal inertial field is transparant to velocity, so all velocities are indistinguishable, but whenever an object accelerates, there is interaction with the universal inertial field, opposing (but not preventing) the acceleration, hence the formula of proportion: F=ma. In a universe without matter the inertial field would be identical to minkowsky space-time everywhere. But matter deforms the inertial field in its neighbourhood, and wherever the universal inertial field is deformed only limited volumes of space are effectively indistinguishable from minkowski space-time. The part of this deformation of space-time geometry that counts the most is the gravitational time dilation. When matter moves through deformed space-time geometry, the line of travel is seen to be curved when looked at from a sufficient distance. Unlike electromagnetic interaction, that is mediated by a "carrier" that travels in space, gravitational interaction is mediated by deformation of the very fabric of space-time itself. Deformation of the gravito-inertial field and deformation of the space-time geometry are one and the same thing in the theory of general relativity.

 * Rotation is not absolute, but according to general relativity it is exceedingly rare to see significant rotation of local space-time geometry with respect to the universe. Hence rotation measured against the locar space-time geometry and rotation with respect to distant stars are invariably seen to match. General relativity does predict under what (extreme) circumstances significant local rotation of space-time geometry with respect to the Universe will occur.

 * When two spaceships are co-accelerating, then their relative velocity is zero. However, when they want to communicate, for example by radio signals, they observe the signals are distorted. Their interaction with space-time affects the signals. It is only when both space-ships are moving inertially that the laws of special relativity apply. When the spaceships are both accelerating they must each take their individual interaction with the universal inertial field into account. --Cleon Teunissen | Talk 18:19, 19 Mar 2005 (UTC)

 * (William M. Connolley 21:44, 19 Mar 2005 (UTC)) The bucket argument proves nothing. Its something to ponder, but no-one has drawn any defendable physical theory from it.

 * Well, Einstein did draw a conclusion from the thought experiment. To Einstein it showed a severe condition that any theory of motion must meet. Einstein agreed with Mach's objection against newtonian absolute space. Newtonian absolute space acts on matter but it is not acted upon, wich, argued Einstein, is profoundly unsatisfacty. Einstein's physics intuition told him that a theory of physics that wants to really represent Nature should describe Nature as interactions between physical things that act upon each other and that are being acted upon. To illustrate the condition that any theory of motion must meet Einstein devised the rotating liquid spheres thought experiment. Einstein argued that this thought experiment proves that there must be an interaction of local matter with distant matter. The problem of taking account of inertia is a problem of information. Independent of the choice of coordinate system, either rotating with respect to the liquid sphere floating almost alone in space, or a coordinate system that has zero rotation with respect to the liquid sphere floating in space, it must be recognized that some mediator is providing the information that determines exactly how much the liquid sphere is bulging at the equator.

 * Any theory that lays claim to being a good representation of Nature must describe a mechanism that relays that information. Einstein believed that general relativity achieves this aim, and the scientific consensus in the community of physicists is that general relativity indeed achieves that aim. Mach's original proposal was that any theory of motion and in particular inertia should not refer in any way to space, Mach argued that it should be about interactions of matter only. Einstein did not follow that proposal of Mach. --Cleon Teunissen | Talk 09:13, 20 Mar 2005 (UTC)

The bucket and the floating globes (new article)
I wrote a new article, after reading Newton's Scholium.

I concentrated on the physics, and I avoided the philosophy. Newton's rotating bucket is not situated in empty space; the two globes, connected by a cord under tension had been situated by Newton in otherwise empty space. The bucket argument is not a thought experiment, it is an inference from something seen in daily life; the two-globes-connected-by-a-cord is a thought experiment. It is understandable that the two have been merged into a bucket-with-water-in-empty-space, but I feel the article should be historically correct.

The globes-and-cord thought experiment is by far the most interesting line of thought, it is wider in scope than the rotating bucket argument.

I decided not to write about Mach's philosophical objections against the tacit assumptions in newtonian dyanamics. --Cleon Teunissen | Talk 18:45, 20 Mar 2005 (UTC)

Category; Classical mechanics
Sebastian (talk) had added to the article, commenting:
 * maybe should be dynamics, but there is no such cat as of now Sebastian (talk) 10:11, 2005 May 20 (UTC)

The current article on Kinematics opens with:
 * In physics, kinematics is the branch of mechanics concerned with the motions of objects without being concerned with the forces that cause the motion. In this latter respect it differs from dynamics, which is concerned with the forces that affect motion.

So the category 'Kinematics' is certainly inappropriate for the bucket argument. The bucket argument is about the philosophy of Classical mechanics. Newton is justifying his concept of laws of motion, he is very much concerned with the forces that are at work. Therefore I have removed the 'Kinematics' category, and replaced it with  --Cleon Teunissen | Talk 15:00, 20 July 2005 (UTC)

"Here Newton tacitly assumes the weight of the globes is known." Shouldn't that be mass??--Hobx 05:36, 3 September 2005 (UTC)

Something wrong?
This page is profoundly confusing, utterly useless for a beginner. I found an older version much more useful to understand things.(http://en.wikipedia.org/w/index.php?title=Bucket_argument&oldid=24025492) Please don't make things complicated just to give them the appearance of 'scientific rigour'. 59.163.146.5 09:04, 20 February 2006 (UTC)

 * I wrote the version that you prefer. My version was replaced, with the comment: 'amateur viewpoint removed'.
 * I have no trouble understanding the current version, being a physicist, and I know the relevant history of physics reasonably well. But I agree with your criticism that the current version is only understandable for people who already have a solid grasp of the subject matter; the current version assumes a lot of prior knowledge in the reader. The current version of the article is written for people who won't look up the article, since they already know.
 * In my version I focused exclusively on Newton's thinking and on translating concepts from newton's time to present day concepts, to make it an article that newbies to the subject can learn from. Maybe a merger should be attempted. Newton was very keen to debunk Descartes. --Cleonis | Talk 11:17, 20 February 2006 (UTC)

 * A few of that version are IMO misreadings, eventhough I base myself on the same translation of Newton. In particular, I think that he did not claim that motion under the influence of a force is true motion.
 * Neverheless there is much of value in that version, and reinserting some of it in the article may improve it for sure - as it is, the article is rather short anyway, so it will be a welcome complement. Harald88 22:35, 7 September 2006 (UTC)

 * The version of article that I wrote does not attribute to Newton a claim that 'motion under the influence of a force coincides with true motion'.
 * What I intended to convey in the version that I wrote is the following: 'true motion (as Newton conceived it) can be thought of in terms two components that add up to a single true motion. The two components are: a true uniform motion, that is unknowable, and accelerated motion (for example: orbiting around the Sun), that is observable.' --Cleonis | Talk 09:03, 10 September 2006 (UTC)

 * Good! Formulated like that, it is much clearer. Harald88 09:11, 10 September 2006 (UTC)

 * I agree. This is MUCH clearer. I am in no way interested in the unrelated explanation for why water takes on a parabola in a a spinning bucket. This needs to be restored or added to the first section of the article.Wmcleod (talk) 16:38, 3 November 2010 (UTC)

A newtonian style defence of absolute space
I'd like to present a line of reasoning, in spirit similar to the rotating bucket and the orbiting spheres. The purpose of presenting this line of reasoning is to show how I think Newton and his contemporaries were thinking.

A mill is built above a little stream of water, the water drives a waterwheel. The miller cannot directly see the stream from his living quarters, and he has build a device for monitoring the flow of water. An airtight sac is floating on the water, the sac has enough buoyancy to support a long pole. The pole extends through the floor of the miller's living quarters, and from the height of the pole the miller can see whether it is worthwile at all to go down and try to get some milling done.

If the pole does not move at all, then presumably the stream is dry. If water is flowing, then fluctuations in the flow of water will make the pole go gently up and down. The miller cannot see the water itself, what he can observe by watching the pole is change in the flow of water. In order for a thing to be changable, the thing itself must exist; water is flowing.

Change of velocity is physically manifest. When a carriage suddenly moves faster, the passengers feel the lunge. Change of velocity exists, we observe it. In order for a thing to be changable, the thing itself must exist. This proves the existence of velocity with respect to absolute space.

As I announced: the above depicts a line of reasoning that I think Newton or a contemporary might have offered.

It is sometimes suggested that Newton was naive in asserting absolute space. But it is the other way round: it is a sign of ignorance to accuse Newton of underestimating the range of options. --Cleonis | Talk 09:58, 10 September 2006 (UTC)

 * I was also impressed by Newton's reasoning. Note that we can only include in the article what has been published. Still, I think that Newton himself made his line of reasoning sufficiently clear, it's just a matter of highlighting and clearly paraphrasing the pertinent passages of his "Scholium". Harald88 10:45, 10 September 2006 (UTC)

 * Of course, I presented the line of reasoning only to offer a guideline of highlighting and paraphrasing pertinent passages of the 'Scholium'.

 * In the version of the article that I wrote it ends with a section that switches to a modern point of view. In the definitions (definition III) Newton defines a concept of 'vis inertia' which today would be called 'reactive inertial force'. If a force is impressed on an object, then due to inertia there is a reactive inertial force that is exerted by object. Newton follows the habit of his time (a habit that is just as current today) to describe inertia as a property of the object in and of itself. In Newton's time the usual name is 'vis insita' the 'life within' the object. The modern point of view is that Newtonian absolute space must be conceived of as acting upon objects, opposing change of velocity. In this view the assumed absolute space is conceived of as the underlying cause of the phenomenon of inertia. It seems it cannot be ascertained for sure whether Newton thought of inertia as an innate property of objects, or as a consequence of absolute space acting upon matter. --Cleonis | Talk 11:30, 10 September 2006 (UTC)

Statement of Descartes' position not understandable
The article proposes:

The use of "it" and "its" which may refer to any of a number of different nouns occurring earlier in the sentence render the meaning obscure. Here are some options:

And so on. Can this sentence be cleared up? It also would be helpful later on to have Descartes' theory as applied to the bucket, so we can see that in fact the bucket experiment contradicts his theory. Brews ohare (talk) 14:11, 12 May 2008 (UTC)

Traditional version of experiment has some problems that may slow understanding
The text currently has: "Presumably, the concavity of the water shows rotation relative to something else: absolute space. This argument is incomplete, as it limits the participants relevant to the experiment to only the pail and the water, which has not been established. In fact, the concavity of the water clearly involves gravitational attraction, and by implication the Earth also is a participant."

The discussion gets unnecessarily complicated when the traditional setting of the thought experiment is used. It doesn't help that the "which has not been established" part above does not really make sense.

The earth and its gravity would participate in how the experiment would look -- if run on earth. And the twisted rope would not work unless it were connected to something at the top and being stretched by the earth and the bucket of water from the bottom. But those factors are just involved because the early writers wanted to make something that could be understood well enough to grasp the essentials.

I've seen a drawing in which the bucket is suspended from a disembodied "hand of God" in an empty universe, but it is presented as a cartoon, not as an attempt to explore the operational factors of the experiment.

The better experiment would put a spaceship through a wormhole into an empty universe (so there is no gravity field from distant stellar objects). Is the spaceship moving? Is it still? There is no meaning to that question. If two spaceships come through and they end up close to each other they may detect that they have a closing velocity with regard to each other. But that gets into another area of the question about whether space is a substance.

With the one ship it is possible to do experiments with acceleration because the ship still has its rockets. But to make things a little more graphic, let's assume that the rocket engines have gone dead, but the ship has hull-mounted projectile weapons. They aim four equally spaced weapons tangentially to the circumference of the ship. Everything we know about the mysterious "thing" called inertia tells us that crewpersons floating at the center of the ship will see the walls start to spin around them. But somebody grabbing a handhold on the inner circumference of the hull will experience the same forces that one experiences riding in a merry-go-round or what the cat in the clothes dryer experiences. (Even one of Schroedinger's. Fame provides no exceptions to inertia.)

In a rotating cylinder, coins ranged side by side around one "great circle" drawn on the hull could be kept in place until jostled or until the stacks got tall enough that there would be no more room for a full complement of coins and there was going to be an overlap. Sooner or later, there would be a stack crash. The dislodged coins would eventually come into contact with the hull at points ranging fore and aft of the original line — slower if in vacuum. As long as the coins and the hull were not frictionless, eventually they would all get accelerated by hull contact and there would be the inevitable "concavity" of the surface of the sea of coins.

In any experiment there would be a acceleration and there would be rotations (at different velocities) relative to some other things -- the propellant, i.e., the projectiles shot off to start the ship rotating. The words "presumably" and "something else, absolute space" do not have to enter here. Definitely the concavity of the water (at both ends of the water cargo, actually) would show rotation because rotation is acceleration as far as movable components are concerned. The real connection to "absolute space" is probably in the existence of the phenomenon called inertia.

Inertia seems to be tied in with a very general empirical generalization: Nothing happens unless some force is exerted. Stones do not jump off mountain peaks. They have to be pushed or dislodged. Asteroids heading straight for collision with earth do not suddenly shear off to avoid a disaster. They have to be pushed or pulled by something. My dirty clothes do not put themselves in the washing machine and flick the switch. No free lunch -- even in an otherwise empty universe, I suspect.

If only one spaceship goes through the wormhole into the empty universe, there is no indication of motion, or of inertia, as long as the spaceship is just floating there. If, however, the spaceship can split in the middle by firing explosive bolts that are holding two spring-loaded halves together, there is motion. It might turn out to be different, but everything in our experience in this universe tells us that the universe does not work in a magical way. Is inertia a function of space? Would what we know as inertia change at great distances if it turns out that the universe is not correctly described by Euclidean geometry? If inertia is primarily a characteristic of the universe, can the universe be given a meaningful account without including something called space? Can the universe and inertia be explained or given a full account if space is interpreted as being only a relationship or set of relationships? P0M (talk) 20:45, 2 July 2008 (UTC)

There is a good discussion by Kant, in the Inaugural Dissertation I think, about the mathematical description of left-handed and right-handed objects. There are some difficulties in giving full descriptions when chirality is involved. If I remember correctly, you have to start with some empirical example of a "left hand" or a "right hand" and then on that basis one can characterize other objects as handed -- but defining them requires reference to some standard. If space is "only a relation," then why are two hands (or two molecules) that are relationally the same different in all kinds of interactions? (Some molecules may be digestible or indigestible depending on whether they are "sinister" or not. ;-)

How abstract can knowledge be and still pertain to and adequately describe our universe? Can space be given an adequate description only in terms of the relations among objects in [it]? Or does space have some characteristic or characteristics that cannot be captured by specifying relationships?

The same kind of questions come up in regard to sequence of events and the direction of the sequence of events. Feynman points to the several kinds of atomic events that look different to us as long as we have the idea, "first there was this particle sitting there and then there was a couple of blasts of energy diverging from that place," and "First these two blasts of energy collided and then there was a particle sitting there," but then you realize that it is the "same thing" happening in different directions. If you get very abstract, there does not seem to be anything to account for the "arrow of time," and to account for that arrow of time it becomes necessary to look at the total probabilities of the events involved in the whole. It is rather unlikely that I might throw an eraser at the blackboard, that it would slot itself neatly into the chalk tray at the bottom and go barreling down to the other end of the blackboard where it hits a hammer resting there that some careless worker left. But happens, maybe at the rate of once in a thousand lifetimes. The probability that some workman hits a resting eraser at the end of the chalkboard, and that it goes toward the other end of the track, suddenly hops up and into contact with the blackboard, then bounces outward and directly into the hands of the instructor who has just turned away from the class and closes his fingers just at the right instant to trap the unexpected missile — well, if anybody wants to gamble I know which side I'll bet on.

With regard to the not entirely abstract characteristics of space, perhaps it will turn out that probability has a part to play. Or maybe not.

How can the original passage quoted above be reformulated so that it does not seem like a "cut" at the idea of absolute space and yet make clear the problematical aspects of a full description of the rotating bucket experiment? "Absolute space," "inertia," etc., all seem to be terms that we might not be able to do without. What are the authoritative sources we can cite to help establish which if any of the traditional concepts can be tossed out as redundant? Can we say, "We don't need inertia because we have absolute space," or, "We don't need absolute space because we can explain everything with relations and/or inertia," or what? P0M (talk) 21:33, 2 July 2008 (UTC)

The effect of the shape of the bucket
The section headed Fluid mechanics says:

the parabolic shape applies only for surface regions sufficiently far from the bucket walls, and for water deep enough to keep the surface away from the bucket bottom

The approximate solution actually does not apply all the way to the bucket walls

For a real bucket and a real liquid, the solution near the bucket walls may become quite complicated

This disagrees with An Introduction to Fluid Mechanics & Heat Transfer by J.M.Kay, which says:

In the special case of the forced vortex the fluid is rotating as a solid object

In which case the surface will not be affected by the shape of the bucket. It will be a paraboloid right up to the edge of the water surface (apart from the meniscus caused by surface tension). So I suspect that the entire Fluid mechanics section of this article is incorrect.

Occultations (talk) 14:18, 20 April 2010 (UTC)

I have removed the entire Fluid mechanics section of this article, because I believe it is incorrect. I think I understand where the misunderstanding came from. In this part of the deleted section:

Lamb points out that the assumed velocity of the liquid has a non-zero curl, and hence cannot be realized in an ideal liquid that cannot support tangential forces. Another way to put this is that the velocity cannot be represented as the gradient of a velocity potential, it is not irrotational, a rather anomalous situation. In particular, it can be shown that any motion generated from rest by impulsive pressure only is necessarily irrotational. For example, if we begin with a stationary fluid with a flat surface, its velocity has zero curl. Then it can be shown that any subsequent velocity configuration obtained by gradually increasing the rotation of the water also will have zero curl.

the referenced document talks about Euler's equation. But Euler's equation only applies to inviscid flow, ie. flow where there is no viscosity. And, indeed, if there is no viscosity then the fluid cannot be rotated up from stationary until the entire mass of fluid is rotating as a solid body. But this article says:

Newton discusses a bucket filled with water hung by a cord. Eventually, as the cord continues to unwind, the surface of the water assumes a concave shape as it acquires the motion of the bucket spinning relative to the experimenter.

So it is clearly talking about a liquid with viscosity. The deleted section therefore does not apply.

Occultations (talk) 17:41, 27 April 2010 (UTC)

POV marking
This article is titled " bucket argument", which refers to Newton's argument for his point of view; at least it should fairly present that argument, that is, elaborate on it, citing secondary sources that defend it. Instead it only cites secondary sources that dispute that argument and even cites these sources as facts; more POV-pushing than that is hardly possible. Harald88 (talk) 08:23, 9 August 2010 (UTC)

For example Einstein's 1920 discussion is a good secondary source for Newton's bucket argument:

" the mechanical behaviour of a corporeal system hovering freely in empty space depends not only on relative positions (distances) and relative velocities, but also on its state of rotation, which physically may be taken as a characteristic not appertaining to the system in itself. In order to be able to look upon the rotation of the system, at least formally, as something real, Newton objectivises space. Since he classes his absolute space together with real things, for him rotation relative to an absolute space is also something real. Newton might no less well have called his absolute space ``Ether``; what is essential is merely that besides observable objects, another thing, which is not perceptible, must be looked upon as real, to enable acceleration or rotation to be looked upon as something real. [emphasis mine]

It is true that Mach tried to avoid having to accept as real something which is not observable by endeavouring to substitute in mechanics a mean acceleration with reference to the totality of the masses in the universe in place of an acceleration with reference to absolute space. But inertial resistance opposed to relative acceleration of distant masses presupposes action at a distance; and as the modern physicist does not believe that he may accept this action at a distance, he comes back once more, if he follows Mach, to the ether, which has to serve as medium for the effects of inertia. But this conception of the ether to which we are led by Mach's way of thinking differs essentially from the ether as conceived by Newton, by Fresnel, and by Lorentz. Mach's ether not only conditions the behaviour of inert masses, but is also conditioned in its state by them. " - http://www.tu-harburg.de/rzt/rzt/it/Ether.html

Harald88 (talk) 08:43, 9 August 2010 (UTC)

.. I note that the POV marking has been removed without correcting the issue. Effectively the article contains 1 century old misinformation, as Mach's principle is not fully included in GR. I'll correct this now with a link to the Wikipedia article that clarifies and elaborates on that. Harald88 (talk) 13:52, 23 October 2016 (UTC)

Is This Actually Relative?
I don't believe that this example truly describes absolute motion. I beleive the water would be spinning, but it would be spinning relative to the bucket, wouldn't it? — Preceding unsigned comment added by MusicAndPhysics (talk • contribs) 01:26, 2 December 2012 (UTC)

..No. And you can try it at home. :-) Harald88 (talk) 13:53, 23 October 2016 (UTC)

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University College Hospital

University College Hospital (UCH) is a teaching hospital in the Fitzrovia area of the London Borough of Camden, England. The hospital, which was founded as the North London Hospital in 1834, is closely associated with University College London (UCL), whose main campus is situated next door. The hospital is part of the University College London Hospitals NHS Foundation Trust.

The hospital is on the south side of Euston Road and its tower faces Euston Square tube station on the east side. Warren Street tube station lies immediately west and the major Euston terminus station is beyond 200 metres east, just beyond Euston Square Gardens.

History
In 1826, the London University began emphasising the importance of having medical schools attached to hospitals. Before the hospital opened, only Oxford and Cambridge universities offered medical degrees, and as a consequence relatively few doctors actually had degrees. The hospital was founded as the North London Hospital in 1834 in order to provide clinical training for the "medical classes" of the university, after a refusal by the governors of the Middlesex Hospital to allow students access to that hospital's wards. It soon became known as University College Hospital.

In 1835, Robert Liston became the first professor of clinical surgery at UCH, and the first major operation under ether in Europe was conducted at the hospital by Liston on 21 December 1846. UCH was split from UCL in 1905, and a new hospital building designed by Alfred Waterhouse, known as the Cruciform Building, was opened in 1906 on Gower Street. UCH merged with the National Dental Hospital in 1914, and the Royal Ear Hospital in 1920.

George Orwell married Sonia Brownell in 1949, and later died 21 January 1950, in room 65 of the hospital. The hospital was run by the Camden and Islington Area Health Authority from 1974. In 1994, UCH became part of the University College London Hospitals NHS Trust. The hospital site at the Cruciform Building was closed in 1995, despite strikes and an occupation in 1993. The building was purchased by UCL, for use as the home for the Wolfson Institute for Biomedical Research and the teaching facility for UCL bioscience and medical students UCL Medical School.

A new 75,822 m2 hospital, procured under the Private Finance Initiative in 2000, designed by Llewelyn Davies Yeang and built by a joint venture of AMEC and Balfour Beatty at a cost of £422 million, opened in 2005. The sculpture Monolith and Shadow made from a large polished piece of Brazilian granite was placed outside the main entrance to the new hospital in 2005.

In October 2006, the hospital was nominated and made the Building Design shortlist for the inaugural Carbuncle Cup, awarded to "the ugliest building in the United Kingdom completed in the last 12 months", which was ultimately awarded to Drake Circus Shopping Centre in Plymouth. Facilities management services are provided by Interserve.

In November 2008, the £70 million Elizabeth Garrett Anderson Wing was opened, allowing the hospital to offer all women's health services in one place (except some breast and gynaecology services).

In 2024, King Charles III became patron of the hospital, a role Queen Elizabeth II had filled until her death in 2022.

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the following services were provided at the hospital:

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The hospital has 665 in-patient beds, 12 operating theatres and houses the largest single critical care unit in the NHS. The Accident and Emergency department sees approximately 120,000 patients a year. It is a major teaching hospital and a key location for the UCL Medical School. It is also a major centre for medical research and part of both the UCLH/UCL Biomedical Research Centre and the UCL Partners academic health science centre.

The urology department moved to University College Hospital at Westmoreland Street, formerly the Heart Hospital, in 2015.

Notable staff

 * Marcus Beck, surgeon (appointed 1863) and Professor of Surgery (1883–1893)
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 * Graham Fraser, consultant and pioneer of cochlear implants in the United Kingdom
 * Harold Lambert, medical doctor and professor of medicine, known for his work dealing with infectious diseases and antibiotic therapy
 * Sir Thomas Lewis, cardiologist at the hospital
 * Jean Smellie, consultant paediatrician (1970–1993)
 * Elizabeth Joan Stokes, medical registrar (1937–40), clinical bacteriologist (1944–77)

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Nancy Lord

Nancy Theresa Lord (February 8, 1952 – February 14, 2022) was an American attorney and medical researcher who was the vice-presidential candidate of the Libertarian Party in the 1992 presidential election, as the running-mate of Andre Marrou. Marrou and Lord placed fourth in the popular vote with 290,087 votes (0.3%). Lord was the Libertarian candidate for Mayor of the District of Columbia in 1990. She also unsuccessfully ran for Nye County, Nevada District Attorney as a Republican in 2010.

Lord completed undergraduate and M.D. degrees at the University of Maryland. She earned her J.D. degree from Georgetown University Law Center. Until 1983, Lord was employed by Abbott Laboratories, where she authored the successful new drug application for benzodiazepine hypnotic ("ProSom"). After leaving Abbott, Lord worked as an independent consultant in the areas of pharmaceutical development, medical malpractice, and toxicology.

She served on the boards of directors for NORML and for the Fully Informed Jury Association and wrote the introduction to the original edition of You and the Police by Boston T. Party. She was married to J.J. Johnson, an African-American organizer of the American militia movement.

Lord died on February 14, 2022, in Show Low, Arizona, following a bout with COVID-19.

title: Nancy Lord