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Reticular formation

The reticular formation is a set of interconnected nuclei that are located in the brainstem, hypothalamus, and other regions. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts.

Neurons of the reticular formation, particularly those of the ascending reticular activating system, basically act as an “on/off” switch to the cerebral cortex and hence play a crucial role in maintaining behavioral arousal and consciousness. The overall functions of the reticular formation are modulatory and premotor, involving somatic motor control, cardiovascular control, pain modulation, sleep and consciousness, and habituation. The modulatory functions are primarily found in the rostral sector of the reticular formation and the premotor functions are localized in the neurons in more caudal regions.

The reticular formation is divided into three columns: raphe nuclei (median), gigantocellular reticular nuclei (medial zone), and parvocellular reticular nuclei (lateral zone). The raphe nuclei are the place of synthesis of the neurotransmitter serotonin, which plays an important role in mood regulation. The gigantocellular nuclei are involved in motor coordination. The parvocellular nuclei regulate exhalation.

The reticular formation is essential for governing some of the basic functions of higher organisms and is one of the phylogenetically oldest portions of the brain.

Structure

The human reticular formation is composed of almost 100 brain nuclei and contains many projections into the forebrain, brainstem, and cerebellum, among other regions. It includes the reticular nuclei, reticulothalamic projection fibers, diffuse thalamocortical projections, ascending cholinergic projections, descending non-cholinergic projections, and descending reticulospinal projections. The reticular formation also contains two major neural subsystems, the ascending reticular activating system and descending reticulospinal tracts, which mediate distinct cognitive and physiological processes. It has been functionally cleaved both sagittally and coronally.

Traditionally the reticular nuclei are divided into three columns:
 * In the median column – the raphe nuclei
 * In the medial column – gigantocellular nuclei (because of larger size of the cells)
 * In the lateral column – parvocellular nuclei (because of smaller size of the cells)

The original functional differentiation was a division of caudal and rostral. This was based upon the observation that the lesioning of the rostral reticular formation induces a hypersomnia in the cat brain. In contrast, lesioning of the more caudal portion of the reticular formation produces insomnia in cats. This study has led to the idea that the caudal portion inhibits the rostral portion of the reticular formation.

Sagittal division reveals more morphological distinctions. The raphe nuclei form a ridge in the middle of the reticular formation, and, directly to its periphery, there is a division called the medial reticular formation. The medial RF is large and has long ascending and descending fibers, and is surrounded by the lateral reticular formation. The lateral RF is close to the motor nuclei of the cranial nerves, and mostly mediates their function.

Medial and lateral reticular formation
The medial reticular formation and lateral reticular formation are two columns of nuclei with ill-defined boundaries that send projections through the medulla and into the midbrain. The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves. Moving caudally from the rostral midbrain, at the site of the rostral pons and the midbrain, the medial RF becomes less prominent, and the lateral RF becomes more prominent.

Existing on the sides of the medial reticular formation is its lateral cousin, which is particularly pronounced in the rostral medulla and caudal pons. Out from this area spring the cranial nerves, including the very important vagus nerve. The lateral RF is known for its ganglions and areas of interneurons around the cranial nerves, which serve to mediate their characteristic reflexes and functions.

Function
The reticular formation consists of more than 100 small neural networks, with varied functions including the following:

 * 1) Somatic motor control – Some motor neurons send their axons to the reticular formation nuclei, giving rise to the reticulospinal tracts of the spinal cord. These tracts function in maintaining tone, balance, and posture – especially during body movements. The reticular formation also relays eye and ear signals to the cerebellum so that the cerebellum can integrate visual, auditory, and vestibular stimuli in motor coordination. Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators, which produce rhythmic signals of breathing and swallowing.
 * 2) Cardiovascular control – The reticular formation includes the cardiac and vasomotor centers of the medulla oblongata.
 * 3) Pain modulation – The reticular formation is one means by which pain signals from the lower body reach the cerebral cortex. It is also the origin of the descending analgesic pathways. The nerve fibers in these pathways act in the spinal cord to block the transmission of some pain signals to the brain.
 * 4) Sleep and consciousness – The reticular formation has projections to the thalamus and cerebral cortex that allow it to exert some control over which sensory signals reach the cerebrum and come to our conscious attention. It plays a central role in states of consciousness like alertness and sleep. Injury to the reticular formation can result in irreversible coma.
 * 5) Habituation – This is a process in which the brain learns to ignore repetitive, meaningless stimuli while remaining sensitive to others. A good example of this is a person who can sleep through loud traffic in a large city, but is awakened promptly due to the sound of an alarm or crying baby. Reticular formation nuclei that modulate activity of the cerebral cortex are part of the ascending reticular activating system.

Ascending reticular activating system
The ascending reticular activating system (ARAS), also known as the extrathalamic control modulatory system or simply the reticular activating system (RAS), is a set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and sleep-wake transitions. The ARAS is a part of the reticular formation and is mostly composed of various nuclei in the thalamus and a number of dopaminergic, noradrenergic, serotonergic, histaminergic, cholinergic, and glutamatergic brain nuclei.

Structure
The ARAS is composed of several neural circuits connecting the dorsal part of the posterior midbrain and anterior pons to the cerebral cortex via distinct pathways that project through the thalamus and hypothalamus. The ARAS is a collection of different nuclei – more than 20 on each side in the upper brainstem, the pons, medulla, and posterior hypothalamus. The neurotransmitters that these neurons release include dopamine, norepinephrine, serotonin, histamine, acetylcholine, and glutamate. They exert cortical influence through direct axonal projections and indirect projections through thalamic relays.

The thalamic pathway consists primarily of cholinergic neurons in the pontine tegmentum, whereas the hypothalamic pathway is composed primarily of neurons that release monoamine neurotransmitters, namely dopamine, norepinephrine, serotonin, and histamine. The glutamate-releasing neurons in the ARAS were identified much more recently relative to the monoaminergic and cholinergic nuclei; the glutamatergic component of the ARAS includes one nucleus in the hypothalamus and various brainstem nuclei. The orexin neurons of the lateral hypothalamus innervate every component of the ascending reticular activating system and coordinate activity within the entire system.

The ARAS consists of evolutionarily ancient areas of the brain, which are crucial to the animal's survival and protected during adverse periods, such as during inhibitory periods of Totsellreflex, aka, "animal hypnosis". The ascending reticular activating system which sends neuromodulatory projections to the cortex - mainly connects to the prefrontal cortex. There seems to be low connectivity to the motor areas of the cortex. <!--

Neurotransmitters
The primary neurotransmitters involved in the RAS are dopamine, norepinephrine, serotonin, histamine, acetylcholine, and glutamate.

Acetylcholine
Shute and Lewis first revealed the presence of a cholinergic component of the RAS, composed of two ascending mesopontine tegmental pathways rostrally situated between the mesencephalon and the centrum semiovale. These pathways involve cholinergic neurons of the posterior midbrain, the pedunculopontine nucleus (PPN) and the laterodorsal tegmental nucleus (LDT), which are active during waking and REM sleep. Cholinergic activity is highest when in an awake state and during REM sleep, and is minimal in non-REM sleep Cholinergic activation in the RAS results in increased acetylcholine release in these areas. Glutamate has also been suggested to play an important role in determining the firing patterns of the tegmental cholinergic neurons.

It has been recently reported that significant portions of posterior PPN cells are electrically coupled. It appears that this process may help coordinate and enhance rhythmic firing across large populations of cells. This unifying activity may help facilitate signal propagation throughout the RAS and promote sleep-wake transitions. It is estimated that 10 to 15% of RAS cells may be electrically coupled.

Norepinephrine
The adrenergic component of the reticular activating system is closely associated with the noradrenergic neurons of the locus coeruleus. Unlike cholinergic neurons, the adrenergic neurons are active during waking and slow wave sleep but cease firing during REM sleep. In addition, adrenergic neurotransmitters are destroyed much more slowly than acetylcholine. This sustained activity may account for some of the time latency during changes of consciousness.

More recent work has indicated that the neuronal messenger nitric oxide (NO) may also play an important role in modulating the activity of the noradrenergic neurons in the RAS. NO diffusion from dendrites regulates regional blood flow in the thalamus, where NO concentrations are high during waking and REM sleep and significantly lower during slow-wave sleep. Furthermore, injections of NO inhibitors have been found to affect the sleep-wake cycle and arousal.

Serotonin
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Consciousness
The ascending reticular activating system is an important enabling factor for the state of consciousness. The ascending system is seen to contribute to wakefulness as characterised by cortical and behavioural arousal.

Regulating sleep-wake transitions
The main function of the ARAS is to modify and potentiate thalamic and cortical function such that electroencephalogram (EEG) desynchronization ensues. There are distinct differences in the brain's electrical activity during periods of wakefulness and sleep: Low voltage fast burst brain waves (EEG desynchronization) are associated with wakefulness and REM sleep (which are electrophysiologically similar); high voltage slow waves are found during non-REM sleep. Generally speaking, when thalamic relay neurons are in burst mode the EEG is synchronized and when they are in tonic mode it is desynchronized. Stimulation of the ARAS produces EEG desynchronization by suppressing slow cortical waves (0.3–1 Hz), delta waves (1–4 Hz), and spindle wave oscillations (11–14 Hz) and by promoting gamma band (20–40 Hz) oscillations.

The physiological change from a state of deep sleep to wakefulness is reversible and mediated by the ARAS. The ventrolateral preoptic nucleus (VLPO) of the hypothalamus inhibits the neural circuits responsible for the awake state, and VLPO activation contributes to the sleep onset. During sleep, neurons in the ARAS will have a much lower firing rate; conversely, they will have a higher activity level during the waking state. In order that the brain may sleep, there must be a reduction in ascending afferent activity reaching the cortex by suppression of the ARAS.

Attention
The ARAS also helps mediate transitions from relaxed wakefulness to periods of high attention. There is increased regional blood flow (presumably indicating an increased measure of neuronal activity) in the midbrain reticular formation (MRF) and thalamic intralaminar nuclei during tasks requiring increased alertness and attention.

Clinical significance of the ARAS
Mass lesions in brainstem ARAS nuclei can cause severe alterations in level of consciousness (e.g., coma). Bilateral damage to the reticular formation of the midbrain may lead to coma or death.

Direct electrical stimulation of the ARAS produces pain responses in cats and elicits verbal reports of pain in humans. Ascending reticular activation in cats can produce mydriasis, which can result from prolonged pain. These results suggest some relationship between ARAS circuits and physiological pain pathways.

Pathology
Some pathologies of the ARAS may be attributed to age, as there appears to be a general decline in reactivity of the ARAS with advancing years. Changes in electrical coupling have been suggested to account for some changes in ARAS activity: if coupling were down-regulated, there would be a corresponding decrease in higher-frequency synchronization (gamma band). Conversely, up-regulated electrical coupling would increase synchronization of fast rhythms that could lead to increased arousal and REM sleep drive. Specifically, disruption of the ARAS has been implicated in the following disorders:
 * Narcolepsy: Lesions along the pedunculopontine (PPT/PPN) / laterodorsal tegmental (LDT) nuclei are associated with narcolepsy. There is a significant down-regulation of PPN output and a loss of orexin peptides, promoting the excessive daytime sleepiness that is characteristic of this disorder.
 * Progressive supranuclear palsy (PSP) : Dysfunction of nitrous oxide signaling has been implicated in the development of PSP.
 * Parkinson's disease: REM sleep disturbances are common in Parkinson's. It is mainly a dopaminergic disease, but cholinergic nuclei are depleted as well.  Degeneration in the ARAS begins early in the disease process.

Developmental influences
There are several potential factors that may adversely influence the development of the ascending reticular activating system:
 * Preterm birth: Regardless of birth weight or weeks of gestation, premature birth induces persistent deleterious effects on pre-attentional (arousal and sleep-wake abnormalities), attentional (reaction time and sensory gating), and cortical mechanisms throughout development.
 * Smoking during pregnancy: Prenatal exposure to cigarette smoke is known to produce lasting arousal, attentional and cognitive deficits in humans. This exposure can induce up-regulation of α4β2 nicotinic receptors on cells of the pedunculopontine nucleus (PPN), resulting in increased tonic activity, resting membrane potential, and hyperpolarization-activated cation current. These major disturbances of the intrinsic membrane properties of PPN neurons result in increased levels of arousal and sensory gating, deficits (demonstrated by a diminished amount of habituation to repeated auditory stimuli). It is hypothesized that these physiological changes may intensify attentional dysregulation later in life.

History
The term "reticular formation" was coined in the late 19th century by Otto Deiters, coinciding with Ramon y Cajal's neuron doctrine. Allan Hobson states in his book The Reticular Formation Revisited that the name is an etymological vestige from the fallen era of the aggregate field theory in the neural sciences. The term "reticulum" means "netlike structure", which is what the reticular formation resembles at first glance. It has been described as being either too complex to study or an undifferentiated part of the brain with no organization at all. Eric Kandel describes the reticular formation as being organized in a similar manner to the intermediate gray matter of the spinal cord. This chaotic, loose, and intricate form of organization is what has turned off many researchers from looking farther into this particular area of the brain. The cells lack clear ganglionic boundaries, but do have clear functional organization and distinct cell types. The term "reticular formation" is seldom used anymore except to speak in generalities. Modern scientists usually refer to the individual nuclei that compose the reticular formation.

Moruzzi and Magoun first investigated the neural components regulating the brain's sleep-wake mechanisms in 1949. Physiologists had proposed that some structure deep within the brain controlled mental wakefulness and alertness. It had been thought that wakefulness depended only on the direct reception of afferent (sensory) stimuli at the cerebral cortex.

As direct electrical stimulation of the brain could simulate electrocortical relays, Magoun used this principle to demonstrate, on two separate areas of the brainstem of a cat, how to produce wakefulness from sleep. He first stimulated the ascending somatic and auditory paths; second, a series of "ascending relays from the reticular formation of the lower brain stem through the midbrain tegmentum, subthalamus and hypothalamus to the internal capsule." The latter was of particular interest, as this series of relays did not correspond to any known anatomical pathways for the wakefulness signal transduction and was coined the ascending reticular activating system (ARAS).

Next, the significance of this newly identified relay system was evaluated by placing lesions in the medial and lateral portions of the front of the midbrain. Cats with mesencephalic interruptions to the ARAS entered into a deep sleep and displayed corresponding brain waves. In alternative fashion, cats with similarly placed interruptions to ascending auditory and somatic pathways exhibited normal sleeping and wakefulness, and could be awakened with physical stimuli. Because these external stimuli would be blocked on their way to the cortex by the interruptions, this indicated that the ascending transmission must travel through the newly discovered ARAS.

Finally, Magoun recorded potentials within the medial portion of the brain stem and discovered that auditory stimuli directly fired portions of the reticular activating system. Furthermore, single-shock stimulation of the sciatic nerve also activated the medial reticular formation, hypothalamus, and thalamus. Excitation of the ARAS did not depend on further signal propagation through the cerebellar circuits, as the same results were obtained following decerebellation and decortication. The researchers proposed that a column of cells surrounding the midbrain reticular formation received input from all the ascending tracts of the brain stem and relayed these afferents to the cortex and therefore regulated wakefulness.

Other references

 * Systems of The Body (2010)
 * Neuroscience (2018)
 * Anatomy and Physiology (2018)
 * Neuroscience (2018)
 * Anatomy and Physiology (2018)
 * Anatomy and Physiology (2018)

title: Reticular formation


text:
User talk:Nuterous

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Great kiskadee

The great kiskadee (Pitangus sulphuratus), called bem-te-vi in Brazil, pitogue in Paraguay, benteveo or bichofeo in Argentina, and luis bienteveo, pitabil, luis grande or chilera in Mexico, is a passerine bird in the tyrant flycatcher family Tyrannidae. It is the only member of the genus Pitangus.

It breeds in open woodland with some tall trees, including cultivation and around human habitation. It is mainly found in Belize, the Lower Rio Grande Valley in southern Texas, and northern Mexico. Cited in Liberia, Guanacaste, Costa Rica in December 2022. Occurs throughout Brazil and Venezuela (especially the central and south-southeastern regions) south to Argentina and Uruguay, Paraguay and central Argentina, the Guyana coastline, and Trinidad. It was introduced to Bermuda in 1957, and to Tobago in about 1970.

Taxonomy
The great kiskadee was described and illustrated in 1648 by the German naturalist Georg Marcgrave in the Historia Naturalis Brasiliae. He used the name Pitangua-guacu, the word for a large flycatcher in the Tupi language. In 1760 the French zoologist Mathurin Jacques Brisson included a description of the species in his Ornithologie based on a specimen collected in Cayenne, French Guiana. He used the French name La Pie-Griesche jaune de Cayenne and the Latin name Lanius Cayanensis Luteus. Although Brisson coined Latin names, these do not conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature.

When the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the twelfth edition in 1766 he added 240 species that had been previously described by Brisson in his Ornithologie. One of these was the great kiskadee. Linnaeus included a terse description, coined the binomial name Lanius sulphuratus, and cited Brisson's work. The specific name sulphuratus is Latin for 'sulphur'. The word had been used by Brisson in describing the yellow colour of the underparts of the bird.

The great kiskadee is now the only species placed in the genus Pitangus that was introduced by the English naturalist William Swainson in 1827. The lesser kiskadee was at one time also placed in Pitangus but in 1984 the American ornithologist Wesley E. Lanyon moved the lesser kiskadee to its own monotypic genus Philohydor. This has been accepted by some ornithologists, but not all. The bird was formerly also known as the Derby flycatcher.

Ten subspecies are recognised:
 * P. s. texanus van Rossem, 1940 – south Texas to east Mexico
 * P. s. derbianus (Kaup, 1852) – west Mexico
 * P. s. guatimalensis (Lafresnaye, 1852) – southeast Mexico to central Panama
 * P. s. rufipennis (Lafresnaye, 1851) – north Colombia and north Venezuela
 * P. s. caucensis Chapman, 1914 – west and south Colombia
 * P. s. trinitatis Hellmayr, 1906 – east Colombia, south and east Venezuela and northwest Brazil, Trinidad
 * P. s. sulphuratus (Linnaeus, 1766) – the Guianas and north, west, central Amazonian Brazil, southeast Colombia, and east Ecuador to southeast Peru
 * P. s. maximiliani (Cabanis & Heine, 1859) – north, east Bolivia and west, central Paraguay to east and south Brazil
 * P. s. bolivianus (Lafresnaye, 1852) – central Bolivia
 * P. s. argentinus Todd, 1952 – east Paraguay, southeast Brazil, and Uruguay to central Argentina

Description
The adult great kiskadee is one of the largest of the tyrant flycatchers. It is 25 to 28 cm in length and weighs 53 to 71.5 g. The head is black with a strong white supercilium and a concealed yellow crown stripe. The upperparts are brown, and the wings and tail are brown with usually strong rufous fringes. The bill is short, thick, and black in color. The similar boat-billed flycatcher (Megarynchus pitangua) has a more massive black bill, an olive-brown back, and very little rufous in the tail and wings. A few other tyrant flycatchers — the social flycatcher (Myiozetetes similis), for example — share a similar color pattern, but these species are markedly smaller.

The call is an exuberant BEE-tee-WEE, and the bird has an onomatopoeic name in different languages and countries: In Brazil its popular name is bem-te-vi ("I saw you well") and in Spanish-speaking countries it is often bien-te-veo ("I see you well") and sometimes shortened to benteveo. In Venezuela it is called "cristofué" or "Christ did it".

Distribution and habitat
The great kiskadee occupies a wide range of habitats, from open grassland with scattered trees to urban areas. Its range extends from the Lower Rio Grande Valley in southern Texas south through Central America to southern Argentina. It does not occur in Chile. The great kiskadee was introduced to Bermuda in 1957. Two hundred birds were imported from Trinidad in an attempt to control the number of lizards, especially the tree lizard (Anolis grahami) which had itself been introduced. The birds bred successfully and by 1976 the population on the island had expanded to around 60,000. The great kiskadee is omnivorous and has failed to control the number of lizards.

Behaviour and ecology
The great kiskadee is a common, noisy, and conspicuous bird. It is almost omnivorous and hunts like a shrike or flycatcher, waiting on an open perch high in a tree to sally out and catch insects in flight or to pounce upon rodents and similar small vertebrates (such as other birds' chicks and bats). It will also take prey (such as small snakes, lizards, frogs, perched insects, spiders, millipedes and land snails) and some seeds and fruit from vegetation by gleaning and jumping for it or ripping it off in mid-hover, and occasionally dives for freshwater snails, fish or tadpoles in shallow water, making it one of the few fishing passerines. It also visits feeding stations to eat bread, dog food, bananas and peanut butter/seed mixture. Kiskadees like to hunt on their own or in pairs, and though they might be expected to make good use of prey flushed by but too large for the smaller birds of the understory, they do not seem to join mixed-species feeding flocks very often. When they do, they hunt in the familiar manner. Such opportunistic feeding behavior makes it one of the commonest birds in urban areas around Latin America; its flashy belly and its shrill call make it one of the most conspicuous.

Breeding
Great kiskadees are monogamous and defend a territory. Both sexes build a large domed nest that has a side entrance. It is chiefly composed of grasses and small twigs but can also incorporate lichen, string, and plastic. The birds will steal material from other nests. The nest is placed in a wide range of sites, often in an exposed position high up in a tree or on man-made structures. Occasionally the nest is placed in a cavity. The clutch is 3 to 4 eggs. These are moderately glossy, light yellowish cream in colour with purplish black and purplish brown spots. The average size is 27.9 x. Only the female incubates the eggs; the male guards the nest while she leaves the nest to feed. The eggs hatch after 16–17 days. The chicks are fed by both parents and fledge after 17–18 days.

Food and feeding
This alert and aggressive bird has a strong and maneuverable flight, which it uses to good effect when it feels annoyed by raptors. Even much larger birds are attacked by the great kiskadee, usually by diving down or zooming straight at them while they are in mid-air. Harsh calls are also often given during these attacks, alerting all potential prey in the area of the predator's presence. If not very hungry, any raptor subject to a great kiskadee's mobbing behavior is likely to leave, as it is well-nigh impossible to make a good catch when subject to the tyrant flycatcher's unwelcome attention. In general, avian predators are liable to steer clear of an alert great kiskadee, lest their hunting success be spoiled, and will hunt the great kiskadee itself – though it is as meaty as a fat thrush – only opportunistically.

To mammalian and squamate predators that can sneak up on the nesting or sleeping birds, it is more vulnerable, however. Even omnivorous mammals as small as the common marmoset (Callithrix jacchus) will try to plunder great kiskadee nests – at least during the dry season when fruits are scarce – despite the birds' attempts to defend their offspring. One of two birds studied in the Parque Nacional de La Macarena of Colombia was parasitized by microfilariae.

Status
Not being appreciated as a songbird, the great kiskadee is not usually kept caged and therefore has escaped the depredations of poaching for the pet trade. Also, its feeding mostly on live prey makes it extremely difficult to keep in captivity. It is not considered threatened by the IUCN.

title: Great kiskadee


text: User talk:67.164.215.230

title: User talk:67.164.215.230


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Okutama, Tokyo

Okutama (奥多摩町) is a town located in the western portion of Tokyo Prefecture, Japan, at a distance of roughly 60 km west-northwest of Tokyo Imperial Palace. , the town had an estimated population of 4,949, and a population density of 22 persons per km2. The total area of the town is 225.53 sqkm.

Geography
Okutama is located in the Okutama Mountains of far western Tokyo. It is geographically the largest municipality in Tokyo. Mount Kumotori, Tokyo's highest peak at 2017 m, divides Okutama from the Okuchichibu region of the neighboring Saitama and Yamanashi Prefectures. Tokyo's northernmost and westernmost points lie in Okutama, as does Lake Okutama, an important source of water for Tokyo, situated above the Ogōchi Dam in the town.

Mountains

 * Mount Kumotori
 * Mount Kumotori, at 2017 m is the highest mountain in Tokyo and the westernmost place of Tokyo. Many plants grow here during the summer, most notably the tsuga. From the summit, there is a clear view of Mount Fuji and the Okuchichibu Mountains.
 * Mount Mitō
 * Because it was forbidden to enter Mount Mitō during the Edo period, there are still many forests of enormous beech trees. Mount Fuji and Mount Kumotori can be seen from the summit, and it attracts many visitors especially during autumn. It is one of the Three Mountains of Okutama.
 * Mount Odake (Tokyo)
 * Mount Ōdake is one of the Three Mountains of Okutama. From the summit at 1266 m, Mount Fuji can be seen to the south and Mount Gozen to the west.
 * Mount Kawanori
 * From Mount Kawanori, all mountains in Okutama can be seen. Also, the Hyakuhiro Waterfall is located here.
 * Mount Gozen
 * Mount Gozen is well known for its oddly perfectly triangular shape. Like Mount Mitō, it attracts visitors in the fall.

Rivers

 * Tama River
 * The Tama River, with a length of 138 km, is the longest river in the prefecture. It flows through the entire prefecture, and the upstream of the river is located in Okutama.
 * Hinohara River
 * The Hinohara River is a rather short and small river located in the western portion of Tokyo.

Lakes

 * Lake Okutama
 * Lake Shiromaru
 * Lake Shiromaru is a rather infamous dam on the Tama River. It has a height of 30.3 m, a length of 61 m, and a volume of 14,161 m3.

Surrounding municipalities
Tokyo Metropolis Saitama Prefecture Yamanashi Prefecture
 * Akiruno
 * Ōme
 * Hinohara
 * Chichibu
 * Hannō
 * Uenohara
 * Kosuge
 * Tabayama

Climate
Okutama has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall. The average annual temperature in Okutama is 10.6 °C. The average annual rainfall is 2091 mm with September as the wettest month. The temperatures are highest on average in August, at around 22.1 °C, and lowest in January, at around minus 1.1 °C.

Demographics
Per Japanese census data, the population of Okutama peaked around the year 1950 and has declined by more than two-thirds since then.

Prehistory
People began settling in Okutama from before the Jōmon Period and many archaeological sites have been found with ancient pottery. During the Yayoi period, rice cultivation began in the flatter lands of present-day Okutama, but most of the area remained covered by forests and only small flat lands existed.

Premodern period
During the Edo period, the area included in present-day Okutama was divided into 16 villages within Musashi Province. In each village, there was one person who served as the mayor, another who served as the leader of a particular group, and another who served as a representative for the farmers. Also, entering Mount Takanosu was forbidden for people of low rank during this time. This was because the people of high rank (government officials and such) hunted with hawks at the mountain, and the officials wanted to keep the hunting grounds for themselves.

Modern period
With the start of the Meiji period, the area of Okutama became part of Nirayama Prefecture except for Kotaba village, which was merged into Maebashi Domain, which then became part of Gunma Prefecture. While Kotaba village was turned into part of Maebashi city, the Okutama area was divided into three villages of Hikawa, Kori, and Ogouchi with the establishment of the modern municipalities system on April 1, 1889. In 1940, Hikawa was elevated to town status. In 1955, Hikawa town, Ogouchi village and Kori village were united, forming the town of Okutama.

Government
Okutama has a mayor-council form of government with a directly elected mayor and a unicameral town council of 12 members. Okutama, collectively with the municipalities of Akiruno, Fussa, Hamura, Hinode, Hinohara and Mizuho,  contributes two members to the Tokyo Metropolitan Assembly. In terms of national politics, the city is part of Tokyo 25th district of the lower house of the Diet of Japan.

Economy
Seasonal tourism, forestry and charcoal production are mainstays of the local economy.

Education
Okutama has two public elementary and one public junior high school operated by the town government.
 * Okutama Junior High School (奥多摩中学校)
 * Hikawa Elementary School (氷川小学校)
 * Kori Elementary School (古里小学校)

Okutama JHS was formed by the merger of Hikawa JHS (氷川中学校) and Kori JHS (古里中学校) in 2015.

The town does not have a high school.

Railway
The East Japan Railway Company serves the town. The Ōme Line, which connects the town with Tachikawa, terminates at Oku-Tama Station.

JR East – Ōme Line
 * Kawai - Kori - Hatonosu - Shiromaru - Oku-Tama

Bus
The Nishi Tokyo Bus Co. carries passengers to Lake Okutama, the Nippara Limestone Cave, Tabayama village and Kosuge village (both in Yamanashi Prefecture) from Oku-Tama Station.

Highway

 * National Highways
 * Prefectural Roads
 * Tokyo Prefectural Road 184 Okutama-Akiruno
 * Tokyo Prefectural Road 204 Nippara Limestone Cave
 * Tokyo Prefectural Road 205
 * Tokyo Prefectural Road 206 Kawano-Kamikawa
 * Tokyo Prefectural Road 205
 * Tokyo Prefectural Road 206 Kawano-Kamikawa

Sister city relations

 * 🇨🇳 Chun'an, Zhejiang, China

Local attractions
All of the town is located in Chichibu-Tama-Kai National Park.
 * Lake Okutama
 * Lake Okutama plays a major role in providing drinking water for the people of Tokyo. The largest lake in Tokyo, it also has a large dam.
 * Mount Takanosu
 * During the Edo Period, the people of low rank were forbidden to enter Mount Takanosu, because it was a hawk hunting ground for the government and military officials. Now, it is open to hikers, and has an elevation of 1736.6 m.
 * Tsurunoyu Onsen
 * Until the construction of Ogouchi Dam, there was a spa town for Tsurunoyu Onsen. (It is now in the depths of the dam.) Now, there are a few inns that use the hot water from the hot spring for their spas. The hot spring is located about 20 minutes by bus from Oku-Tama Station.
 * Hyakuhiro Waterfall
 * Hyakuhiro Waterfall, with a height of 40 m, is a famous waterfall in the Okutama area. Located in Mount Kawanori, it is part of the Nippara River.
 * Nippara Cave
 * Nippara Cave is the second largest limestone cave in the Kantō region after the Fujido Cave in Gunma Prefecture, and attracts many visitors from around Japan.
 * Okuchichibu Mountains
 * The Okuchichibu Mountains stretch from Nagano's Nobeyama region to Okutama and a portion of Saitama Prefecture and Yamanashi Prefecture. The highest mountain is Mount Kurogane (Yamanashi Prefecture), at 2232 m, and the lowest is Mount Azumaya (Saitama Prefecture), at 772 m.
 * Okutama Onsen
 * Okutama Onsen is a hot spring located in the town.

title: Okutama, Tokyo


text:
Dentatus

Dentatus may refer to:
 * Manius Curius Dentatus (died 270 BC), son of Manius, a three-time consul and a plebeian hero of the Roman Republic
 * Dimocarpus dentatus, a species of tree related to the Longan

title: Dentatus


text:
User:Thomas Ruefner

I started contributing to the English Wikipedia in January 2005. I work mostly on articles concerning law and legal history. For more personal information, you may take a look at my homepage.

Articles that I started or made major contributions to
Alberico Gentili, Scipione Gentili, Bartolus de Saxoferrato, Doctors' Commons,Bernardino de Mendoza, Bourgeois tragedy, Altdorf bei Nürnberg, Altorf, Azo (Jurist), Francis Throckmorton, Roman law, Fritz Schulz, Hugues Doneau, Roman Dutch law, François Douaren, Frederick A. Schroeder,Hugh McLaughlin (politician), Martin William Currie.

de:Benutzer:Thomas Rüfner la:Usor:Thomas Ruefner

title: User:Thomas Ruefner


text:
Desnoyers

Desnoyers is a surname. Notable people with the surname include:

 * Auguste Gaspard Louis Desnoyers (1800–1887), French engraver
 * Daniel Desnoyers, Canadian radio host and DJ
 * Jules Desnoyers (1800–1887), French geologist and archaeologist
 * Luc Desnoyers (born 1950), Canadian politician
 * Peter J. Desnoyers (1772–1846), Detroit silversmith and businessman
 * Peter Desnoyers (1800–1880), Detroit businessman and politician

title: Desnoyers


text: User talk:129.143.4.68

title: User talk:129.143.4.68


text:
Wikipedia:Articles for deletion/Organic time

 This page is an archive of the discussion about the proposed deletion of the article below. This page is no longer live. Further comments should be made on the article's talk page rather than here so that this page is preserved as an historic record. The result of the debate was delete. Joyous 03:35, Feb 25, 2005 (UTC)

Organic time
Original research. See No original research. Was also a signed essay. Originally concluded: "For time travelling, we must know better our temporal mechanisms, and surely we will obtain an constructive answer to this problem" Kappa 07:08, 15 Feb 2005 (UTC)

 * Delete. Original research. JoaoRicardo 07:43, 15 Feb 2005 (UTC)
 * Delete, original research. -- Curps 11:11, 15 Feb 2005 (UTC)
 * Delete. Original Research. utcursch 12:20, Feb 15, 2005 (UTC)
 * Delete as original research. HyperZonk 16:47, Feb 15, 2005 (UTC)
 * Delete, original research (written by someone who speaks English as a second language), drivel iced with copy-pastes from a reference text. Welcome to the information age. Wyss 18:39, 15 Feb 2005 (UTC)

This page is now preserved as an archive of the debate and, like some other VfD subpages, is no longer 'live'. Subsequent comments on the issue, the deletion, or the decision-making process should be placed on the relevant 'live' pages. Please do not edit this page.