oscillator photos on Flickr

DIY: dds60 kit (60MHz rf sine/square signal generator using AD9851 chip) by linux-works

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vendor link:

midnightdesignsolutions.com/dds60/index.html

the presentation, labeling and packing of this earns an A+ ! I've never gotton such a well labelled kit before; not even from heathkit ;)

photo with the instructions (color, printed!):

www.flickr.com/photos/linux-works/6979839745/in/photostream

"RF: its what's for dinner!"

DSCF1648 by John

RF EHT supply in development. Oscillator valve is a 6M5. This was changed to 6AQ5. Rectifier is 6X2.

green sine by Brandon Daniel

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crt/tube oscilloscopes are the best for this sort of thing. This is a sine wave from a PlanB model 15 oscillator, BTW.

According to the intarweb thingy (and we all know we can trust THAT), the Beastie Boys often use this exact model scope for visuals.

Organo oscillators by mahmoud786110

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Bleep Labs Thingamakit, slightly modded. by Mark Dalzell

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This is the foundation for some other modules I'm building... have good working prototypes of a keyboard and an Ondes Martenot style controller for it so far.

I've added inputs for both oscillators so it can be played more like a normal musical instrument... 90% of the time I'm using the Ondes Martenot controller through oscillator 1, but I also have a neat little keyboard I made that gets some use. I'd like to make a tannerin/ribbon controller for it, but am having a lot of trouble finding something* with the proper resistance. For my next trick, I'm doing a CV input for oscillator 2 and an optical sequencer for oscillator 1. Thanks to Hack-A-Day for some of the mods and Diet Coke and Penguin Mints for the rest.

Audio sample using the Ondes Martenot module

Another sample using the Ondes Martenot module

A sample using a keyboard module

The Smoove Sailors

* finding something means scouring my junk-filled guitar store slash laboratory... I could probably do the static strap controller if I really worked at it, but the ondes controller is so freakin' cool that I'm happy for now.

Home made noisebox in walnut by fsm vpggru

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Five drone voices whose pitch can be tuned by the massive knob at the bottom or by an LDR at the top. The medium size knob is the speed of essentially an LFO that sends a little "blip" to the volume of the voice below. These create a fun poly-rhythm/phasing between the five voices. The speed of this LFO can also respond to an LDR at the top.

The whole thing is housed in some beautiful walnut, finished in Danish oil with a plywood face.

A video youtu.be/9mdVZb-LE1U

Bonding wires 1 by Cole L

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oscillator by Jacob Marcinek

gift for company holiday party

Cat - Domestic Cat - House Cat (Felis Catus) by PHOTOGRAPHY by DM & DBM.

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The cat (Felis catus), commonly referred to as the domestic cat or house cat, is the only domesticated species in the family Felidae. Recent advances in archaeology and genetics have shown that the domestication of the cat occurred in the Near East around 7500 BC. It is commonly kept as a house pet and farm cat, but also ranges freely as a feral cat avoiding human contact. It is valued by humans for companionship and its ability to kill vermin. Because of its retractable claws it is adapted to killing small prey like mice and rats. It has a strong flexible body, quick reflexes, sharp teeth, and its night vision and sense of smell are well developed. It is a social species, but a solitary hunter and a crepuscular predator. Cat communication includes vocalizations like meowing, purring, trilling, hissing, growling, and grunting as well as cat body language. It can hear sounds too faint or too high in frequency for human ears, such as those made by small mammals. It also secretes and perceives pheromones.

Female domestic cats can have kittens from spring to late autumn in temperate zones and throughout the year in equatorial regions, with litter sizes often ranging from two to five kittens. Domestic cats are bred and shown at events as registered pedigreed cats, a hobby known as cat fancy. Animal population control of cats may be achieved by spaying and neutering, but their proliferation and the abandonment of pets has resulted in large numbers of feral cats worldwide, contributing to the extinction of bird, mammal and reptile species.

As of 2017, the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned and around 42 million households owning at least one cat. In the United Kingdom, 26% of adults have a cat, with an estimated population of 10.9 million pet cats as of 2020. As of 2021, there were an estimated 220 million owned and 480 million stray cats in the world.

Etymology and naming

The origin of the English word cat, Old English catt, is thought to be the Late Latin word cattus, which was first used at the beginning of the 6th century. The Late Latin word may be derived from an unidentified African language. The Nubian word kaddîska 'wildcat' and Nobiin kadīs are possible sources or cognates. The Nubian word may be a loan from Arabic قَطّ‎ qaṭṭ ~ قِطّ qiṭṭ.

The forms might also have derived from an ancient Germanic word that was imported into Latin and then into Greek, Syriac, and Arabic. The word may be derived from Germanic and Northern European languages, and ultimately be borrowed from Uralic, cf. Northern Sámi gáđfi, 'female stoat', and Hungarian hölgy, 'lady, female stoat'; from Proto-Uralic *käďwä, 'female (of a furred animal)'.

The English puss, extended as pussy and pussycat, is attested from the 16th century and may have been introduced from Dutch poes or from Low German puuskatte, related to Swedish kattepus, or Norwegian pus, pusekatt. Similar forms exist in Lithuanian puižė and Irish puisín or puiscín. The etymology of this word is unknown, but it may have arisen from a sound used to attract a cat.

A male cat is called a tom or tomcat (or a gib, if neutered). A female is called a queen or a molly, if spayed, especially in a cat-breeding context. A juvenile cat is referred to as a kitten. In Early Modern English, the word kitten was interchangeable with the now-obsolete word catling.

A group of cats can be referred to as a clowder or a glaring.

Taxonomy

The scientific name Felis catus was proposed by Carl Linnaeus in 1758 for a domestic cat. Felis catus domesticus was proposed by Johann Christian Polycarp Erxleben in 1777. Felis daemon proposed by Konstantin Satunin in 1904 was a black cat from the Transcaucasus, later identified as a domestic cat.

In 2003, the International Commission on Zoological Nomenclature ruled that the domestic cat is a distinct species, namely Felis catus. In 2007, it was considered a subspecies, F. silvestris catus, of the European wildcat (F. silvestris) following results of phylogenetic research. In 2017, the IUCN Cat Classification Taskforce followed the recommendation of the ICZN in regarding the domestic cat as a distinct species, Felis catus.

Evolution

Main article: Cat evolution

The domestic cat is a member of the Felidae, a family that had a common ancestor about 10 to 15 million years ago. The evolutionary radiation of the Felidae began in Asia during the Miocene around 8.38 to 14.45 million years ago. Analysis of mitochondrial DNA of all Felidae species indicates a radiation at 6.46 to 16.76 million years ago. The genus Felis genetically diverged from other Felidae around 6 to 7 million years ago. Results of phylogenetic research shows that the wild members of this genus evolved through sympatric or parapatric speciation, whereas the domestic cat evolved through artificial selection. The domestic cat and its closest wild ancestor are diploid and both possess 38 chromosomes and roughly 20,000 genes.

Domestication

See also: Domestication of the cat and Cats in ancient Egypt

It was long thought that the domestication of the cat began in ancient Egypt, where cats were venerated from around 3100 BC, However, the earliest known indication for the taming of an African wildcat was excavated close by a human Neolithic grave in Shillourokambos, southern Cyprus, dating to about 7500–7200 BC. Since there is no evidence of native mammalian fauna on Cyprus, the inhabitants of this Neolithic village most likely brought the cat and other wild mammals to the island from the Middle Eastern mainland. Scientists therefore assume that African wildcats were attracted to early human settlements in the Fertile Crescent by rodents, in particular the house mouse (Mus musculus), and were tamed by Neolithic farmers. This mutual relationship between early farmers and tamed cats lasted thousands of years. As agricultural practices spread, so did tame and domesticated cats. Wildcats of Egypt contributed to the maternal gene pool of the domestic cat at a later time.

The earliest known evidence for the occurrence of the domestic cat in Greece dates to around 1200 BC. Greek, Phoenician, Carthaginian and Etruscan traders introduced domestic cats to southern Europe. During the Roman Empire they were introduced to Corsica and Sardinia before the beginning of the 1st millennium. By the 5th century BC, they were familiar animals around settlements in Magna Graecia and Etruria. By the end of the Western Roman Empire in the 5th century, the Egyptian domestic cat lineage had arrived in a Baltic Sea port in northern Germany.

The leopard cat (Prionailurus bengalensis) was tamed independently in China around 5500 BC. This line of partially domesticated cats leaves no trace in the domestic cat populations of today.

During domestication, cats have undergone only minor changes in anatomy and behavior, and they are still capable of surviving in the wild. Several natural behaviors and characteristics of wildcats may have pre-adapted them for domestication as pets. These traits include their small size, social nature, obvious body language, love of play, and high intelligence. Captive Leopardus cats may also display affectionate behavior toward humans but were not domesticated. House cats often mate with feral cats. Hybridisation between domestic and other Felinae species is also possible, producing hybrids such as the Kellas cat in Scotland.

Development of cat breeds started in the mid 19th century. An analysis of the domestic cat genome revealed that the ancestral wildcat genome was significantly altered in the process of domestication, as specific mutations were selected to develop cat breeds. Most breeds are founded on random-bred domestic cats. Genetic diversity of these breeds varies between regions, and is lowest in purebred populations, which show more than 20 deleterious genetic disorders.

Characteristics

Main article: Cat anatomy

Size

The domestic cat has a smaller skull and shorter bones than the European wildcat. It averages about 46 cm (18 in) in head-to-body length and 23–25 cm (9.1–9.8 in) in height, with about 30 cm (12 in) long tails. Males are larger than females. Adult domestic cats typically weigh 4–5 kg (8.8–11.0 lb).

Skeleton

Cats have seven cervical vertebrae (as do most mammals); 13 thoracic vertebrae (humans have 12); seven lumbar vertebrae (humans have five); three sacral vertebrae (as do most mammals, but humans have five); and a variable number of caudal vertebrae in the tail (humans have only three to five vestigial caudal vertebrae, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and the pelvis. Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones which allow them to pass their body through any space into which they can fit their head.

Skull

The cat skull is unusual among mammals in having very large eye sockets and a powerful specialized jaw. Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two long canine teeth, inserting them between two of the prey's vertebrae and severing its spinal cord, causing irreversible paralysis and death. Compared to other felines, domestic cats have narrowly spaced canine teeth relative to the size of their jaw, which is an adaptation to their preferred prey of small rodents, which have small vertebrae.

The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' small molars cannot chew food effectively, and cats are largely incapable of mastication.: Cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar. Nonetheless, they are subject to occasional tooth loss and infection.

Claws

Cats have protractible and retractable claws. In their normal, relaxed position, the claws are sheathed with the skin and fur around the paw's toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows for the silent stalking of prey. The claws on the forefeet are typically sharper than those on the hindfeet. Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, kneading, or for extra traction on soft surfaces. Cats shed the outside layer of their claw sheaths when scratching rough surfaces.

Most cats have five claws on their front paws and four on their rear paws. The dewclaw is proximal to the other claws. More proximally is a protrusion which appears to be a sixth "finger". This special feature of the front paws on the inside of the wrists has no function in normal walking but is thought to be an antiskidding device used while jumping. Some cat breeds are prone to having extra digits ("polydactyly"). Polydactylous cats occur along North America's northeast coast and in Great Britain.

Ambulation

The cat is digitigrade. It walks on the toes, with the bones of the feet making up the lower part of the visible leg. Unlike most mammals, it uses a "pacing" gait and moves both legs on one side of the body before the legs on the other side. It registers directly by placing each hind paw close to the track of the corresponding fore paw, minimizing noise and visible tracks. This also provides sure footing for hind paws when navigating rough terrain. As it speeds up from walking to trotting, its gait changes to a "diagonal" gait: The diagonally opposite hind and fore legs move simultaneously.

Balance

Cats are generally fond of sitting in high places or perching. A higher place may serve as a concealed site from which to hunt; domestic cats strike prey by pouncing from a perch such as a tree branch. Another possible explanation is that height gives the cat a better observation point, allowing it to survey its territory. A cat falling from heights of up to 3 m (9.8 ft) can right itself and land on its paws.

During a fall from a high place, a cat reflexively twists its body and rights itself to land on its feet using its acute sense of balance and flexibility. This reflex is known as the cat righting reflex. A cat always rights itself in the same way during a fall, if it has enough time to do so, which is the case in falls of 90 cm (3.0 ft) or more. How cats are able to right themselves when falling has been investigated as the "falling cat problem".

Coats

Main article: Cat coat genetics

The cat family (Felidae) can pass down many colors and patterns to their offspring. The domestic cat genes MC1R and ASIP allow for the variety of color in coats. The feline ASIP gene consists of three coding exons. Three novel microsatellite markers linked to ASIP were isolated from a domestic cat BAC clone containing this gene and were used to perform linkage analysis in a pedigree of 89 domestic cats that segregated for melanism.[citation needed]

Senses

Main article: Cat senses

Vision

A cat's nictitating membrane shown as it blinks

Cats have excellent night vision and can see at only one-sixth the light level required for human vision. This is partly the result of cat eyes having a tapetum lucidum, which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light. Large pupils are an adaptation to dim light. The domestic cat has slit pupils, which allow it to focus bright light without chromatic aberration. At low light, a cat's pupils expand to cover most of the exposed surface of its eyes. The domestic cat has rather poor color vision and only two types of cone cells, optimized for sensitivity to blue and yellowish green; its ability to distinguish between red and green is limited. A response to middle wavelengths from a system other than the rod cells might be due to a third type of cone. This appears to be an adaptation to low light levels rather than representing true trichromatic vision. Cats also have a nictitating membrane, allowing them to blink without hindering their vision.

Hearing

The domestic cat's hearing is most acute in the range of 500 Hz to 32 kHz. It can detect an extremely broad range of frequencies ranging from 55 Hz to 79 kHz, whereas humans can only detect frequencies between 20 Hz and 20 kHz. It can hear a range of 10.5 octaves, while humans and dogs can hear ranges of about 9 octaves. Its hearing sensitivity is enhanced by its large movable outer ears, the pinnae, which amplify sounds and help detect the location of a noise. It can detect ultrasound, which enables it to detect ultrasonic calls made by rodent prey. Recent research has shown that cats have socio-spatial cognitive abilities to create mental maps of owners' locations based on hearing owners' voices.

Smell

Cats have an acute sense of smell, due in part to their well-developed olfactory bulb and a large surface of olfactory mucosa, about 5.8 cm2 (0.90 in2) in area, which is about twice that of humans. Cats and many other animals have a Jacobson's organ in their mouths that is used in the behavioral process of flehmening. It allows them to sense certain aromas in a way that humans cannot. Cats are sensitive to pheromones such as 3-mercapto-3-methylbutan-1-ol, which they use to communicate through urine spraying and marking with scent glands. Many cats also respond strongly to plants that contain nepetalactone, especially catnip, as they can detect that substance at less than one part per billion. About 70–80% of cats are affected by nepetalactone. This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herb valerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.

Taste

Cats have relatively few taste buds compared to humans (470 or so versus more than 9,000 on the human tongue). Domestic and wild cats share a taste receptor gene mutation that keeps their sweet taste buds from binding to sugary molecules, leaving them with no ability to taste sweetness. They, however, possess taste bud receptors specialized for acids, amino acids like protein, and bitter tastes. Their taste buds possess the receptors needed to detect umami. However, these receptors contain molecular changes that make the cat taste of umami different from that of humans. In humans, they detect the amino acids of glutamic acid and aspartic acid, but in cats they instead detect nucleotides, in this case inosine monophosphate and l-Histidine. These nucleotides are particularly enriched in tuna. This has been argued is why cats find tuna so palatable: as put by researchers into cat taste, "the specific combination of the high IMP and free l-Histidine contents of tuna" .. "produces a strong umami taste synergy that is highly preferred by cats". One of the researchers involved in this research has further claimed, "I think umami is as important for cats as sweet is for humans".[87]

Cats also have a distinct temperature preference for their food, preferring food with a temperature around 38 °C (100 °F) which is similar to that of a fresh kill; some cats reject cold food (which would signal to the cat that the "prey" item is long dead and therefore possibly toxic or decomposing).

Whiskers

To aid with navigation and sensation, cats have dozens of movable whiskers (vibrissae) over their body, especially their faces. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protective blink reflexes to protect the eyes from damage.: 47

Behavior

See also: Kitten

The cat secretes and perceives pheromones. Female cats, called queens, are polyestrous with several estrus cycles during a year, lasting usually 21 days. They are usually ready to mate between early February and August in northern temperate zones and throughout the year in equatorial regions.

Several males, called tomcats, are attracted to a female in heat. They fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually, the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat's penis has a band of about 120–150 backward-pointing penile spines, which are about 1 mm (0.039 in) long; upon withdrawal of the penis, the spines may provide the female with increased sexual stimulation, which acts to induce ovulation.

After mating, the female cleans her vulva thoroughly. If a male attempts to mate with her at this point, the female attacks him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat. Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate. Furthermore, cats are superfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.

The morula forms 124 hours after conception. At 148 hours, early blastocysts form. At 10–12 days, implantation occurs. The gestation of queens lasts between 64 and 67 days, with an average of 65 days.

Data on the reproductive capacity of more than 2,300 free-ranging queens were collected during a study between May 1998 and October 2000. They had one to six kittens per litter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents. The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed. Kittens reach puberty at the age of 9–10 months.

Cats are ready to go to new homes at about 12 weeks of age, when they are ready to leave their mother. They can be surgically sterilized (spayed or castrated) as early as seven weeks to limit unwanted reproduction. This surgery also prevents undesirable sex-related behavior, such as aggression, territory marking (spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed before puberty, at about three to six months. In the United States, about 80% of household cats are neutered.

Lifespan and health

Main articles: Cat health and Aging in cats

The average lifespan of pet cats has risen in recent decades. In the early 1980s, it was about seven years,: 33 rising to 9.4 years in 1995: 33 and an average of about 13 years as of 2014 and 2023. Some cats have been reported as surviving into their 30s, with the oldest known cat dying at a verified age of 38.

Neutering increases life expectancy: one study found castrated male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females.: 35 Having a cat neutered confers health benefits, because castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer.

Disease

Main article: List of feline diseases

About 250 heritable genetic disorders have been identified in cats, many similar to human inborn errors of metabolism. The high level of similarity among the metabolism of mammals allows many of these feline diseases to be diagnosed using genetic tests that were originally developed for use in humans, as well as the use of cats as animal models in the study of the human diseases. Diseases affecting domestic cats include acute infections, parasitic infestations, injuries, and chronic diseases such as kidney disease, thyroid disease, and arthritis. Vaccinations are available for many infectious diseases, as are treatments to eliminate parasites such as worms, ticks, and fleas.

Ecology

Habitats

The domestic cat is a cosmopolitan species and occurs across much of the world. It is adaptable and now present on all continents except Antarctica, and on 118 of the 131 main groups of islands, even on the isolated Kerguelen Islands. Due to its ability to thrive in almost any terrestrial habitat, it is among the world's most invasive species. It lives on small islands with no human inhabitants. Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.

The unwantedness that leads to the domestic cat being treated as an invasive species is twofold. On one hand, as it is little altered from the wildcat, it can readily interbreed with the wildcat. This hybridization poses a danger to the genetic distinctiveness of some wildcat populations, particularly in Scotland and Hungary, possibly also the Iberian Peninsula, and where protected natural areas are close to human-dominated landscapes, such as Kruger National Park in South Africa. However, its introduction to places where no native felines are present also contributes to the decline of native species.

Ferality

Main article: Feral cat

Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas. The numbers of feral cats is not known, but estimates of the United States feral population range from 25 to 60 million. Feral cats may live alone, but most are found in large colonies, which occupy a specific territory and are usually associated with a source of food. Famous feral cat colonies are found in Rome around the Colosseum and Forum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.

Public attitudes toward feral cats vary widely, from seeing them as free-ranging pets to regarding them as vermin.

Some feral cats can be successfully socialized and 're-tamed' for adoption; young cats, especially kittens and cats that have had prior experience and contact with humans are the most receptive to these efforts.

Impact on wildlife

Main article: Cat predation on wildlife

On islands, birds can contribute as much as 60% of a cat's diet. In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a "mesopredator release" effect; where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail, and the New Zealand merganser are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery. One feral cat in New Zealand killed 102 New Zealand lesser short-tailed bats in seven days. In the US, feral and free-ranging domestic cats kill an estimated 6.3 – 22.3 billion mammals annually.

In Australia, the impact of cats on mammal populations is even greater than the impact of habitat loss. More than one million reptiles are killed by feral cats each day, representing 258 species. Cats have contributed to the extinction of the Navassa curly-tailed lizard and Chioninia coctei.

Interaction with humans

Main article: Human interaction with cats

Cats are common pets throughout the world, and their worldwide population as of 2007 exceeded 500 million. As of 2017, the domestic cat was the second most popular pet in the United States, with 95.6 million cats owned and around 42 million households owning at least one cat. In the United Kingdom, 26% of adults have a cat, with an estimated population of 10.9 million pet cats as of 2020. As of 2021, there were an estimated 220 million owned and 480 million stray cats in the world.

Cats have been used for millennia to control rodents, notably around grain stores and aboard ships, and both uses extend to the present day.

As well as being kept as pets, cats are also used in the international fur trade and leather industries for making coats, hats, blankets, stuffed toys, shoes, gloves, and musical instruments. About 24 cats are needed to make a cat-fur coat. This use has been outlawed in the United States since 2000 and in the European Union (as well as the United Kingdom) since 2007.

Cat pelts have been used for superstitious purposes as part of the practice of witchcraft, and are still made into blankets in Switzerland as traditional medicine thought to cure rheumatism.

A few attempts to build a cat census have been made over the years, both through associations or national and international organizations (such as that of the Canadian Federation of Humane Societies) and over the Internet, but such a task does not seem simple to achieve. General estimates for the global population of domestic cats range widely from anywhere between 200 million to 600 million. Walter Chandoha made his career photographing cats after his 1949 images of Loco, an especially charming stray taken in, were published around the world. He is reported to have photographed 90,000 cats during his career and maintained an archive of 225,000 images that he drew from for publications during his lifetime.

Shows

Main article: Cat show

A cat show is a judged event in which the owners of cats compete to win titles in various cat-registering organizations by entering their cats to be judged after a breed standard. It is often required that a cat must be healthy and vaccinated in order to participate in a cat show. Both pedigreed and non-purebred companion ("moggy") cats are admissible, although the rules differ depending on the organization. Competing cats are compared to the applicable breed standard, and assessed for temperament.

Infection

Main article: Feline zoonosis

Cats can be infected or infested with viruses, bacteria, fungus, protozoans, arthropods or worms that can transmit diseases to humans. In some cases, the cat exhibits no symptoms of the disease. The same disease can then become evident in a human. The likelihood that a person will become diseased depends on the age and immune status of the person. Humans who have cats living in their home or in close association are more likely to become infected. Others might also acquire infections from cat feces and parasites exiting the cat's body. Some of the infections of most concern include salmonella, cat-scratch disease and toxoplasmosis.

History and mythology

Main articles: Cultural depictions of cats and Cats in ancient Egypt

In ancient Egypt, cats were worshipped, and the goddess Bastet often depicted in cat form, sometimes taking on the war-like aspect of a lioness. The Greek historian Herodotus reported that killing a cat was forbidden, and when a household cat died, the entire family mourned and shaved their eyebrows. Families took their dead cats to the sacred city of Bubastis, where they were embalmed and buried in sacred repositories. Herodotus expressed astonishment at the domestic cats in Egypt, because he had only ever seen wildcats.

Ancient Greeks and Romans kept weasels as pets, which were seen as the ideal rodent-killers. The earliest unmistakable evidence of the Greeks having domestic cats comes from two coins from Magna Graecia dating to the mid-fifth century BC showing Iokastos and Phalanthos, the legendary founders of Rhegion and Taras respectively, playing with their pet cats. The usual ancient Greek word for 'cat' was ailouros, meaning 'thing with the waving tail'. Cats are rarely mentioned in ancient Greek literature. Aristotle remarked in his History of Animals that "female cats are naturally lecherous." The Greeks later syncretized their own goddess Artemis with the Egyptian goddess Bastet, adopting Bastet's associations with cats and ascribing them to Artemis. In Ovid's Metamorphoses, when the deities flee to Egypt and take animal forms, the goddess Diana turns into a cat.

Cats eventually displaced weasels as the pest control of choice because they were more pleasant to have around the house and were more enthusiastic hunters of mice. During the Middle Ages, many of Artemis's associations with cats were grafted onto the Virgin Mary. Cats are often shown in icons of Annunciation and of the Holy Family and, according to Italian folklore, on the same night that Mary gave birth to Jesus, a cat in Bethlehem gave birth to a kitten. Domestic cats were spread throughout much of the rest of the world during the Age of Discovery, as ships' cats were carried on sailing ships to control shipboard rodents and as good-luck charms.

Several ancient religions believed cats are exalted souls, companions or guides for humans, that are all-knowing but mute so they cannot influence decisions made by humans. In Japan, the maneki neko cat is a symbol of good fortune. In Norse mythology, Freyja, the goddess of love, beauty, and fertility, is depicted as riding a chariot drawn by cats. In Jewish legend, the first cat was living in the house of the first man Adam as a pet that got rid of mice. The cat was once partnering with the first dog before the latter broke an oath they had made which resulted in enmity between the descendants of these two animals. It is also written that neither cats nor foxes are represented in the water, while every other animal has an incarnation species in the water. Although no species are sacred in Islam, cats are revered by Muslims. Some Western writers have stated Muhammad had a favorite cat, Muezza. He is reported to have loved cats so much, "he would do without his cloak rather than disturb one that was sleeping on it". The story has no origin in early Muslim writers, and seems to confuse a story of a later Sufi saint, Ahmed ar-Rifa'i, centuries after Muhammad. One of the companions of Muhammad was known as Abu Hurayrah ("father of the kitten"), in reference to his documented affection to cats.

Superstitions and rituals

Many cultures have negative superstitions about cats. An example would be the belief that encountering a black cat ("crossing one's path") leads to bad luck, or that cats are witches' familiars used to augment a witch's powers and skills. The killing of cats in Medieval Ypres, Belgium, is commemorated in the innocuous present-day Kattenstoet (cat parade). In mid-16th century France, cats would be burnt alive as a form of entertainment, particularly during midsummer festivals. According to Norman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized". The remaining ashes were sometimes taken back home by the people for good luck.

According to a myth in many cultures, cats have multiple lives. In many countries, they are believed to have nine lives, but in Italy, Germany, Greece, Brazil and some Spanish-speaking regions, they are said to have seven lives, while in Arabic traditions, the number of lives is six. An early mention of the myth can be found in John Heywood's The Proverbs of John Heywood (1546)

Husband, (quoth she), ye studie, be merrie now,

And even as ye thinke now, so come to yow.

Nay not so, (quoth he), for my thought to tell right,

I thinke how you lay groning, wife, all last night.

Husband, a groning horse and a groning wife

Never faile their master, (quoth she), for my life.

No wife, a woman hath nine lives like a cat.

The myth is attributed to the natural suppleness and swiftness cats exhibit to escape life-threatening situations. Also lending credence to this myth is the fact that falling cats often land on their feet, using an instinctive righting reflex to twist their bodies around. Nonetheless, cats can still be injured or killed by a high fall.

News from represented artist Brian House and again an amazing work to be shown. Sound UP🔺 FASCISTS, LOVERS, AND OTHER LONELY GHOSTS 2018 A large collection of small oscillators has a desire to synchronize. Just like fireflies, the cells by Gallery Nosco

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via Instagram ift.tt/2QpIfwr

Taming Electrons 12 by David Fyans

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A few documentation shots of the multi oscillator, light reactive synths I've been building for various performances as part of Sanctuary 2015. They use the amazingly hardy perennial favourite IC, the 40106 CMSOS Schmitt trigger.

There are also a couple of not synths, but percussive instruments made from jars, piezo electric contact mics and m3 nuts and a silver dollar respectively,

Moog Modular 55 by grobie

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Needs your free vote of support at: goo.gl/heBmZ7

With enough votes, it could be made into an actual set by LEGO!

Also, please check out my Minimoog models at: goo.gl/iucWKS

AND

the Prism & Spectrum at: goo.gl/pFTr3v

Nikola Tesla Museum: Colorado Springs Photo by Esa Ruoho

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"Burning the nitrogen of the atmosphere. This result is produced by the discharge of an electrical oscillator giving twelve million volts. The electrical pressure, alternating one hundred thousand times per second, excites the normally inert nitrogen causing it to combine with oxygen. The flame-like discharge measures sixty-five feet across."

Buchla Modular Synthesizer by Paul

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SFSU Electronic Music Lab 1987 (under the direction of Dr. Herb Bielawa). This rig contains parts of the original San Francisco Tape Music Center Buchla 100 series modular synthesizer, including an 8 stage sequencer, a rack of Moog filters (HP, LP and BP) and a rack of house-made modules ("guerilla modules"). Not seen is the 16 step Buchla "keyboard" which was (remarkably for when it was built) pressure sensitive and each key was independently tunable. A great rig.

Vintage Philips QB 3.5/750 Tetrode Vacuum Tube by Sascha Grant

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This Philips QB 3.5/750 Tetrode vacuum tube is designed for use as a High Frequency amplifier and oscillator. It has an output of around 750 watts!

I received it as a gift some years ago and it's been sitting in a box in want of a new home. Since I'm not going to put it into service, I thought I would make up an acrylic display housing for it, so now it sits in my lounge room where I can enjoy it!

This is a big tube - Really big! The tube is 145mm high x 87mm wide.

Want to see what this tube looks like running? Check out this!

historische-elektronik.piranho.de/Hyperlink%20F/EL6471%20...

This 1000w amp has two :)

I found a data sheet on line with a sketch of the base, so was able to transpose this into CorelDRAW. I lasercut the box with enough clearance for the tube to 'float' in the middle. The Philips logo is engraved into the inside-surface of the sides.

Electromagnetic Sound Art - Disinformation at the Hayward Gallery, June 2000 by disinformation

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Advertisement printed in Art Monthly magazine (June 2000, issue 237) announcing the performance “with live mains electricity” by sonic arts project Disinformation, which was presented live at the Hayward Gallery, London, on the 2nd June 2000. Four years after the first performance of “National Grid” (at club Disobey, 1996) the Hayward Gallery performance employed three electromagnetic sources - re-tuned electrical noise from live mains transformers (“National Grid”, published 1996), shortwave radio noise from the sun (“Stargate”, also 1996), plus live radio noise from the sound and light installation “Artificial Lightning”, also by Disinformation.

The “Artificial Lightning” installation was set-up in a (large) darkened space, between the “Mantle” exhibit by Russell Mills and Ian Walton, and the “Civic Recovery Centre” by Brian Eno. The performance took place inside this space, was well advertised (in Art Monthly, Time Out and The Wire magazines) and was physically packed - so well attended that it proved impossible to fit the whole audience in. The Hayward Gallery deemed the performance to have been a success… because young people turned-up “wearing expensive trainers” (direct quote).

The Hayward Gallery’s catalogue for “Sonic Boom” documents the Disinformation artworks “National Grid”, the “Negatives of Lightning” and “The Analysis of Beauty”, and the “Sonic Boom” CDs feature a recording of “National Grid”. The catalogue also features photos of coastal air-defence Sound Mirrors, from the “Blackout” project, and a 2-page spectrogram of the extraordinarily musical swooping and swirling radio noise produced by “Artificial Lightning”. In terms of electromagnetic sound art, “National Grid” precedes works such as “Electrical Walks” by fellow “Sonic Boom” exhibitor Christina Kubisch by seven years.

The “Artificial Lightning” exhibit was described as “actively thrilling” and “admirable” by William Packer (in the Financial Times), while Sci-Fi author Jeff Noon wrote (in The Independent) that “people are fascinated by this work”. Sian Ede (of the Calouste Gulbenkian Foundation) described the exhibit as “way and ahead the best piece in Sonic Boom”. Reviewing “Sonic Boom” for the same issue of Art Monthly (page 35), sound artist David Cunningham described the Disinformation exhibit however as “disturbing” and as featuring “aggressive oscillators” (there were no oscillators).

The “Artificial Lightning” exhibit was later re-titled “The Origin of Painting” (in homage to “The Maid of Corinth, or the Origin of Painting” by the eighteenth century painter Joseph Wright), and has since been exhibited throughout the UK, and in Holland, Belgium and Spain, more than 30 times. The “Sonic Boom” exhibition drew over 36,000 visitors - just under 700 per day. “The Origin of Painting” exhibition at Fabrica (Brighton, 2001) was attended by 9,300 people - 332 per day, which was pretty good, especially considering the huge difference is resources.

The Art Monthly advertisement also announces performances by the artist David Toop, who curated Sonic Boom in conjunction with Fiona Bradley, and by the artist Harry Bertoia. Sonic Boom exhibitors included Angela Bulloch, Paul Burwell, Disinformation, Heri Dono, Max Eastley, Brian Eno, Paulo Feliciano, Greyworld, Stephan von Huene, Ryoji Ikeda, Philip Jeck, Thomas Köner, Christina Kubisch, Chico MacMurtie, Christian Marclay, Katarina Matiasek, Russell Mills, Mariko Mori, John Oswald, Pan Sonic, Project Dark, Lee Ranaldo, Scanner, Paul Schütze, Rafael Toral and Ian Walton.

www.flickr.com/photos/disinfo/22175744070/

Special thanks to Tim Register

figure_osc5-eps-converted-to-pdf-000001 by Grzegorz Link

Contagion in the world's stock exchanges seen as a set of coupled oscillators. Bellenzier, Andersen, Rotundo arxiv.org/abs/1602.07452 #q-fin

Il mare dà, il mare toglie ... by Irene Tartaglia Polcini

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Nel cerchio imperfetto del suo universo ottico la perfezione di quel moto oscillatorio formulava promesse che l'irripetibile unicità di ogni singola onda condannava a non essere mantenute. (Alessandro Baricco, Oceano Mare)

Calunium v2 by Steve Marple

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Arduino clone with real-time clock, microSD socket and radio module. The layout is designed for easy assembly and maximum compatibility with the Arduino Uno, with additional functionality being compatible with the Arduino Mega2560. The optional LM61 temperature sensor is not fitted. As this particular board is intended to be powered by a boost regulator fitted to a shield the 3.3V and 5V regulators, and power LED, have not been fitted.

Version 2 features a number of improvements: there are footprints for SOIC and DIP package real-time clocks and a 5V regulator has been added. The PCB now supports the latest Arduino shield layout, with dedicated pins for I2C and IOREF signals, and 3.3V or 5V operation is possible via a jumper. An RFM12B radio module and microSD socket have been added, both are restricted to 3.3V operation. The microcontroller can be clocked from either an external crystal or ceramic oscillator. The analogue supply is smoothed with an inductor as recommended in the Atmel datasheet.

For more information see blog.stevemarple.co.uk/2012/12/calunium-version-2.html.

Eagle PCB design files available under Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) licence, github.com/stevemarple/Calunium

Nikon F4 by Süleyman (Deceased 04.2012)

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Manufactured by Nikon Corporation, Japan

Model: c.1995 (produced between 1988-1997)

F4s version: with High Speed Battery Pack MB-21

35mm film Integral-motor SLR system camera

BODY

Lens release: button on the left side of the lens flange

Lens mount: Nikon F mount Lenses usable: AF Nikkor lenses and Nikon MF F-mount lenses

Focus modes: Manual focus with electronic rangefinder and Autofocus

Autofocus:

Autofocus detection system: TTL phase detection system using Nikon advanced AM200 autofocus module

Autofocus detection range: Approx. EV minus 1 to EV 18 at ISO 100 (under Nikon inspection conditions)

Autofocus actuation method: Single Servo or Continuous Servo

Autofocus lock: Possible by lightly pressing shutter release button in Single Servo AF mode or by using AF-L button; simultaneous use with AE-L button possible

Electronic rangefinder: Available in Manual focus mode with AF Nikkor lenses, Ai-type Nikkor lenses including Ai-modified Nikkor lenses and non-Ai-type Nikkor lenses with a maximum aperture of f/5.6 or faster

Exposure metering: Matrix Metering (with Multi-Meter Finder DP-20); Center-Weighted Metering (with Multi-Meter Finder DP-20 or AE Action Finder DA-20); Spot Metering (with any finder)

Exposure meter switch: Activated by lightly pressing shutter release button; stays on for approx. 16 sec. after lifting finger from button

Metering range: EV 0 to EV 21 at ISO 100 with f/1.4 lens; EV 2 to EV 21 with Spot Metering

Exposure control: Manual (M), and Programmed (PH, P), Shutter-Priority (S) and Aperture Priority (A) Auto Exposure

Auto exposure lock: Available by pressing AE-L button while meter is on

Exposure compensation: Possible using exposure compensation dial within ±2 EV range in 1/3 EV steps

Multiple exposure: Via a leveron the right back side of the top plate; setting: 1. Pull the multiple exposure lever toward you and release the shutter. The film will not advance. Multiple exposure lever is automatically reset to the original position. 2. Depress the shutter release button again to take the second shot. Film will advance to the next frame. For more than two shots on the same frame, pull the lever before each additional exposure.

Depth-of-field preview button: Provides visual verification of depth of field; can be previewed in Manual (M) or Aperture Priority (A) mode; coaxial with mirror lockup lever

Reflex mirror: Automatic instant-return type with lockup facility; to lock the reflex viewing mirror in the "up" position, push in the depth-of-field preview button and rotate the mirror lockup lever counterclockwise until it stops. (In this case, exposure meter cannot be used.)

This means that you cannot operate the camera in any auto exposure and/or autofocus mode anymore (even if the viewfinder LCD may indicate information). Any indication of light by the LCD is a result of spurious light entering through the view finder eyepiece. However, you can make use of the camera's suggested metering and use it in Manual mode.

Shutter: Electro-magnetically controlled vertical-travel titanium focal plane shutter; dial on the top plate, Manual and Shutter-Priority Auto Exposure modes

Shutter release: Electromagnetic shutter by magnet trigger, on the top plate

Alternate shutter release button: there is a shutter release button is provided at the bottom of the High Speed Battery Pack MB-21 as well as the Multiple Power High Speed Power Pack MB-23. This is convenient for vertical format shooting. The button can be locked to prevent inadvertent shutter release. Note: all F4 has another release terminal at the bottom rear section.

Shutter speeds: Lithium niobate oscillator-controlled; controlled from 1/8800 to 30 sec. steplessly in PH, P or A mode; set from 1/8800 to 4 sec. in one EV steps in M or S mode; B, T and X (1/250 sec.)

Viewfinder: Nikon Multi-Meter Finder DP-20 provided as standard; SLR pentaprism, High-Eyepoint type; metering system selector, diopter adjustment knob, hot-shoe, compensation dial for focusing screens and eyepiece shutter lever provided; interchangeable with Nikon AE Action Finder DA-20, Nikon 6X High-Magnification Finder DW-21 and Nikon Waist-Level Finder DW-20

Viewfinder information: By LCD - exposure compensation value, frame counter (additive type), metering system in use, shutter speed, aperture, exposure mode, electronic analog display, AE Lock indicator; by ADR window - lens aperture; by LED display - focus indicators, exposure compensation mark and flash ready-light. Illuminator switch provided for dim-light viewing

Viewfinder illuminator switch: When it's dark, use the viewfinder illuminator to light up all viewfinder information. Turn the switch on, and lightly press the shutter release button to illuminate the display. The illuminator automatically switches off as the viewfinder display disappears; it also momentarily switches off during exposure. Beneath the shutter speeds dial

Eyepoint: Approx. 22mm

Focusing screen: Nikon advanced B-type BriteView screen with central focus brackets for autofocus operation; interchangeable with 12 optional screens

Film speed range: ISO 25 to 5000 for DX-coded film; ISO 6 to 6400 in 1/3 EV steps for manual setting Film speed setting: At DX position, automatically set to ISO speed of DX-coded film used; manual override possible

Film loading: Film automatically advances to first frame when shutter release button is depressed once

Auto film loading: The user simply pulls the film leader to the mark closes the camera back then presses the shutter release button - and the camera automatically advances the film to frame #1.A bright LED will lit and stays on for approx. 16 sec. in such case, the film advance operation will halt as well.

Winding: In S (single frame) shooting mode, film automatically advances one frame when shutter is released; in CH (Continuous high speed), CL (Continuous low speed) or Cs (Continuous silent) shooting mode, shots are taken as long as shutter release button is depressed; shooting speed is approx. 5.7 fps (CH), 3.4 fps (CL) or 1.0 fps (Cs) - for Continuous Servo Autofocus, test done with an AF Zoom-Nikkor 35-80mm f/4-5.6D lense, new six AA-type alkaline batteries, shutter speed of 1/250 sec. or faster, at normal temperature.

Frame counter: Two additive types provided - on top of camera and inside viewfinder (LCD)

Re-winding: Choice of automatic or manual; automatically rewinds when film rewind levers (R1) and (R2) are used; takes approx. 8 sec. per 36-exposure roll (with six AA-type batteries); (with six AA-type batteries); stops automatically when film is rewound; manual rewind when R1 lever is used

Self-timer: Electronically controlled 10 sec. exposure delay; blinking LED indicates self timer operation; cancelable; setting: via the last setting on the film advance mode

Hot-shoe: Standard ISO-type hotshoe contact; ready light contact, TTL flash contact, monitor contact

Flash sync:1/60 to 1/250 sec. in PH, P or A mode; in M or S mode, shutter fires at speed set and when set from 1/250 to 1/8800 sec., shutter is automatically set to 1/250 sec.; down to 30 sec. shutter is available by using SB-24, SB-26 or other equivalent Nikon speedlights etc. in rear curtain sync in PH, P or A mode Flash ready-light: Viewfinder LED lights up when Nikon dedicated Speedlight is ready to fire; blinks to warn of poor camera/ Speedlight connection or insufficient light for correct exposure

Flash PC socket: A separate sync terminal is provided on the Nikon F4. Use this terminal to attach flash units which do not have the standard ISO hot shoe.

Batteries: six AA-type alkaline or NiCd batteries

Battery chambers: two, on the High Speed Battery Pack MB-21

Body:metal; Weight:

Serial no. 2.499.403

LENS

AF Nikkor 50mm f/1.8 D

Aperture: f/1.8-f/22

Focus range: 0.45-3m +inf

Serial no. 636334, Made in China

More info: Dating, Ken Rocwell com,

Technical Specifications in Mir com, in Nikon com

Lingua Ignota @ Roadburn, 2020 by deepskyobject

Lingua Ignota @ #Roadburn2020

для тех кто пропустил главную сенсацию Rb 2019 — теперь она сыграет аж 4 раза на Rb 2020

Kristin Hayter дважды выступила на #Roadburn2019, оба концерта я конечно посмотрел и особенно меня ошарашил сэт в Green Room с овераншлагом, когда она пела прямо из зала, стоя среди зрителей и на экран во время этого проецировали апокалиптическое VHS где догорали некие постройки, лес и надвигались сумерки

total recall:

#Roadburn2019 @ Tilburg

D1: Lingua Ignota, Heilung, Rakta, Hexvessel, Malokarpatan, Pharmakon, Mono & The Jo Quail Quartet, Crowhurst, Midnight, Emma Ruth Rundle, Molasses, Twin Temple

D2: Triptykon & Metropole Orkest: Requiem, Anna Von Hausswolff, Loop, Grails, Messa, A.A.Williams, Black Bombaim & Peter Brötzmann, Thou & Emma Ruth Rundle, Lingua Ignota (Skatepark), Seven That Spells (pt 1), At The Gates, Fauna, Vile Creature (Skatepark), Drab Majesty, Bosse-de-Nage

D3: Uran GBG, Wolvennest, Turia, GlerAkur, Henrik Palm, Laster, Cave In, Morne, Louise Lemón, Have A Nice Life, Sumac, Maalstroom, Terzij de Horde, Jaye Jayle

D4: Sleep, MJ Guider (Melissa Guion), Imperial Triumphant, Marissa Nadler, Thou, Mats Gustafsson's The End, Bismuth (Skatepark), Cave, Nusquama (Turia, Laster, Fluisteraars), Mord‘A’Stigmata, Crowhurst & Gnaw Their Tongues, Lucy In Blue, Have A Nice Life, Coilguns, Fear Falls Burning

fl: flic.kr/s/aHsmtLBdy2

...

#Roadburn2018

D1: Årabrot, Kælan Mikla, Future Occultism (Bong-Ra, Servants Of The Apocalyptic Goat Rave, Phurpha), Earthless, Horte, Wreck and Reference, Harsh Toke, Weedeater, Stomach Earth

D2: Minami Deutsch 南ドイツ, Motorpsycho, Godflesh, Jarboe ft. Father Murphy, Kairon; Irse!, Planning For Burial, Converge (You Fail Me), Kikagaku Moyo, Worship, Joy (San Diego), Grave Pleasures

D3: Boris & Stephen O’Malley - Absolutego, Hugsjá - Ivar Bjørnson (Enslaved) & Einar Selvik (Wardruna), NYIÞ & Wormlust - Hieros Gamos, Earthess & Kikagaku Moyo, Zola Jesus, Mizmor (Yodh), Maggot Heart, Godspeed You! Black Emperor (vol I), Occvlta, Panopticon, The Heads, All Pigs Must Die

D4: Godspeed You! Black Emperor (vol II), Alda, Spotlights, Vánagandr: Sól án varma (Misþyrming, Naðra, Svartidauði, Wormlust), Wiegedood, Watter, Bell Witch, Vampillia, GosT, Zuriaake, Hell (Salem)

fl: flic.kr/s/aHsmaaMKZ2

...

#Roadburn2017

D1: Esben and The Witch, Deafheaven, Coven, Subrosa, Suma, Rome, Wolves In The Throne Room, Lycus, Alaric, Bongzilla

D2: Auðn, True Widow, Amenra, Chelsea Wolfe, Magma, Oathbreaker, Subrosa (Subdued), Naðra, Perturbator, Zhrine, Telepathy, Whores

D3: Oranssi Pazuzu, Mysticum, Wolvennest, Aluk Todolo, The Bug vs Dylan Carlson of Earth, Trans Am, Misþyrming, My Dying Bride, Disfear, Ahab, Memoriam, Cobalt

D4: Ulver, Emma Ruth Rundle, Come To Grief, Inter Arma, Radar Men From The Moon, Jaye Jayle, Les Discrets, Oxbow, Pillorian (Agalloch, John Haughm), The Doomsday Kingdom

fl: flic.kr/s/aHskNWb1QV

...

#Roadburn2016

D1: Oranssi Pazuzu, Der Blutharsch & The Infinite Church of The Leading Hand, Paradise Lost, Cult of Luna, Hell, Arktau Eos, Grafir, Black Mountain, Abyssion (Dark Buddha Rising + Oranssi Pazuzu), Hexvessel, Cult of Occultt, Converge, Bang, Behold! The Monolith, The Body

D2: Misþyrming (Úlfsmessa), Of The Wand And The Moon, Hills, Alkerdeel, With the Dead, Dark Buddha Rising, Diamanda Galás, Mondo Drag, Night Viper, G.I.S.M., Repulsion, Pentagram

D3: Blood Ceremony, Amenra, Misþyrming, Skepticism, Partisan, Atomikylä, John Haughm (Agalloch), Chaos Echoes, Dead To A Dying World, La Muerte, Russell Haswell, Tau Cross, Naðra, Brothers of the Sonic Cloth, Neurosis

fl: flic.kr/s/aHsky3Mpu1

...

#Roadburn2015

D1: Wovenhand, Kandodo feat. Robert Hampson (Loop), Monolord, Russian Circles, Anthroprophh, Moaning Cities

D2: Skuggsjá (Wardruna & Enslaved), Focus, Wardruna, Enslaved, Downfall of Gaia, Death Hawks, Fields of the Nephilim, Junius, Mortals, Profetus, Robert Hampson, Sólstafir, The Heads, Admiral Sir Cloudesley Shovell

D3: Kayo Dot, Undersmile, Urfaust, Zombi, Mugstar (Ad Marginem), Sammal

D4: Claudio Simonetti's Goblin (Suspiria, Argento), Anathema, White Hills, Bongripper

fl: flic.kr/s/aHskaaZuDd

lj: is.gd/hXDNhJ

...

#Roadburn2014

D1: True Widow, Conan, Bong, The Cult of Dom Keller, Regarde Les Hommes Tomber, Whitehorse, Beastmilk, Mühr, Corrections House, ASG, Napalm Death

D2: Terra Tenebrosa, Nicklas Barker (Anekdoten) + Reine Fiske (Dungen), Claudio Simonetti (Goblin), Änglagård, Promise and the Monster, The Body, Comus, Opeth, Papir, Tyranny, Procession, Candlemass, Obliteration

D3: Windhand, Loop (Robert Hampson), Inter Arma, Obelyskkh, Papir, E-Musikgruppe Lux Ohr, Horse Latitudes, Mansion, Old Man Gloom, Carlton Melton, 11 Paranoias (Bong+Ramesses), Horse Latitudes, A Storm Of Light

D4: Avatarium, Aqua Nebula Oscillator, Lumerians, New Keepers of the Water Towers, Papir + Electric Moon, YOB, Morne, Selim Lemouchi & His Enemies (tribute to The Devil's Blood)

fl: flic.kr/s/aHsm223Ztk

...

#Roadburn2013

D1: Lantlôs, The Psychedelic Warlords, Intronaut, Maserati, Gravetemple, Herder, Mournful Congregation, Pallbearer, Primordial

D2: Uncle Acid & the Deadbeats, Electric Wizard, Psychic TV / PTV3, Sabbath Assembly, Les Discrets, Cough, Moss, Goat, The Pretty Things

D3: My Brother The Wind, Elder, Mr. Peter Hayden, Teeth of the Sea, A Forest of Stars, The Cosmic Dead, Godflesh, Jess and the Ancient Ones

D4: Michael Rother & Camera (Neu! Harmonia), Electric Moon, Sigh, Goat, Spiritual Beggars

fl: flic.kr/s/aHsmfBsXRF

lj: is.gd/jYVz9h

...

#Roadburn2012

D1: Ulver, Chelsea Wolfe, Voivod, Killing Joke, Om, Agalloch, d.USK, Orchid, Ancestors, Ancient VVisdom, Year of the Goat

D2: Anekdoten, Electric Moon, Barn Owl, Doom, Hexvessel, Final, YOB, Conan, Gnod, Witch

D3: Oranssi Pazuzu, Sleep, Church of Misery, Jesu, Alkerdeel, 40 Watt Sun, Dark Buddha Rising

D4: The Mount Fuji Doomjazz Corporation, Bong, Electric Orange, Dragged Into Sunlight, Black Cobra

fl: flic.kr/s/aHskyST3wi

lj: is.gd/WLZtXF

...

#Roadburn2011

D1: Wardruna, Blood Ceremony, Cough, Godflesh, Wovenhand, Acid King, Alcest, The Kilimanjaro Darkjazz Ensemble

D2: Sunn O))), Earth, Aluk Todolo, Winter, Keiji Haino, Voivod, Circle with Pharaoh Overlord, Sabbath Assembly, Year of No Light (Vampyr soundtrack), Jesse Sykes and the Sweet Hereafter, Menace Ruine, Void ov Voices

D3: Ufomammut, Swans, Yakuza, Ramesses, White Hills, Ludicra, Pharaoh Overlord, Shrinebuilder, Candlemass, Weedeater

D4: Dead Meadow, Black Mountain, Black Pyramid, Sourvein, Samsara Blues Experiment

fl: flic.kr/s/aHsktiVqXH

lj: is.gd/HxKyzQ

Essex - Westcliff-on-Sea - Promenade Prior to 1912. And the Life and Death of Henri Poincaré. by pepandtim

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The Postcard

A postcard bearing no publisher's name that was posted in Southend-on-Sea on Wednesday the 17th. July 1912 to:

Miss Richardson,

'Balmoral',

Marine Parade,

Barmouth,

N. Wales.

The pencilled message on the back of the card was as follows:

"Wed.

Dear Maudie,

Glad you are having a

fine time.

I walked along here

with Father yesterday.

The scenery is

indescribable.

Father uses the camera,

he hasn't used all the

plates yet.

We are most anxious to

see the results.

Much love to all,

Ella".

Westcliff-on-Sea

Westcliff-on-Sea is a suburb of Southend-on-Sea and a seaside resort in Essex in south-east England.

It is situated on the north bank of the Thames Estuary, about 34 miles (55 km) east of London.

The cliffs formed by erosion give views over the Thames Estuary towards the Kent coastline to the south. The coastline has been transformed into sandy beaches through the use of groynes and imported sand.

The estuary at this point has extensive mud flats. At low tide, the water typically retreats some 600 m from the beach, leaving the mud flats exposed.

The London, Tilbury and Southend Railway line arrived in the 1880's, connecting the town with London and shortening travel time.

-- Hamlet Court Road

The main shopping area in Westcliff-on-Sea is Hamlet Court Road, where the department store Havens, established in 1901, remained the anchor store until its closure in 2017.

Hamlet Court Road took its name from a manor house called Hamlet Court, which stood on land now occupied by Pavarotti's restaurant and the NatWest bank, facing towards the sea with sweeping gardens down to the rail line.

The road later developed into a strong independent retail area, and quickly became famous outside the area as the Bond Street of Essex. There were many haberdashers and specialist shops, and it was not unusual to see chauffeurs waiting for their employers to emerge from the shops.

The economic recessions of the 1980's and 90's saw the area decline. However the road underwent a £1 million regeneration in the early 2000's and a further regeneration in 2010. The street is now known for its large number of restaurants.

Henri Poincaré

So what else happened on the day that Ella posted the card to Maudie?

Well, the 17th. July 1912 was not a good day for Henri Poincaré, because he died in Paris on that day at the young age of 58.

Jules Henri Poincaré was a French mathematician, theoretical physicist, engineer, and philosopher of science. He is often described as a polymath, and in mathematics as "The Last Universalist", since he excelled in all fields of the discipline as it existed during his lifetime.

As a mathematician and physicist, he made many original contributions to pure and applied mathematics, mathematical physics, and celestial mechanics. In his research on the three-body problem, Poincaré became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. He is also considered to be one of the founders of the field of topology.

Poincaré emphasised the importance of paying attention to the invariance of laws of physics under different transformations, and was the first to present the Lorentz transformations in their modern symmetrical form.

Poincaré discovered the remaining relativistic velocity transformations, and recorded them in a letter to Hendrik Lorentz in 1905. Thus he obtained perfect invariance of all of Maxwell's equations, an important step in the formulation of the theory of special relativity.

In 1905, Poincaré first proposed gravitational waves (ondes gravifiques) emanating from a body and propagating at the speed of light as being required by the Lorentz transformations.

The Poincaré group used in physics and mathematics was named after him.

Early in the 20th. century he formulated the Poincaré conjecture that became over time one of the famous unsolved problems in mathematics until it was solved in 2002–2003 by Grigori Perelman.

-- Henri Poincaré - The Early Years

Poincaré was born on the 29th. April 1854 in the Cité Ducale neighborhood, Nancy, Meurthe-et-Moselle, into an influential French family. His father Léon Poincaré (1828–1892) was a professor of medicine at the University of Nancy.

His younger sister Aline married the spiritual philosopher Émile Boutroux. Another notable member of Henri's family was his cousin, Raymond Poincaré, a fellow member of the Académie Française, who was President of France from 1913 to 1920.

During his childhood Henri was seriously ill for a time with diphtheria, and received special instruction from his mother, Eugénie Launois (1830–1897).

In 1862, Henri entered the Lycée in Nancy. He spent eleven years at the Lycée, and during this time he proved to be one of the top students in every topic he studied. He excelled in written composition. His mathematics teacher described him as a "monster of mathematics," and he won first prizes in the Concours Général, a competition between the top pupils from all the Lycées across France.

Henri's poorest subjects were music and physical education, where he was described as "average at best". However, poor eyesight and a tendency towards absentmindedness may explain these difficulties.

He graduated from the Lycée in 1871 with a baccalauréat in both letters and sciences.

During the Franco-Prussian War of 1870, he served alongside his father in the Ambulance Corps.

Poincaré entered the École Polytechnique as the top qualifier in 1873 and graduated in 1875. There he studied mathematics as a student of Charles Hermite, continuing to excel and publishing his first paper (Démonstration nouvelle des propriétés de l'indicatrice d'une surface) in 1874.

From November 1875 to June 1878 he studied at the École des Mines, while continuing the study of mathematics in addition to the mining engineering syllabus, and received the degree of ordinary mining engineer in March 1879.

As a graduate of the École des Mines, he joined the Corps des Mines as an inspector for the Vesoul region in northeast France. He was on the scene of a mining disaster at Magny in August 1879 in which 18 miners died. He carried out the official investigation into the accident in a characteristically thorough and humane way.

At the same time, Poincaré was preparing for his doctorate in mathematics under the supervision of Charles Hermite. His doctoral thesis was in the field of differential equations. It was named Sur les propriétés des fonctions définies par les équations aux différences partielles.

Poincaré devised a new way of studying the properties of these equations. He not only faced the question of determining the integral of such equations, but also was the first person to study their general geometric properties. He realised that they could be used to model the behaviour of multiple bodies in free motion within the Solar System.

Poincaré graduated from the University of Paris in 1879.

-- Henri Poincaré's First Scientific Achievements

After receiving his doctorate, Poincaré began teaching as junior lecturer in mathematics at the University of Caen in Normandy. At the same time he published his first major article concerning the treatment of a class of automorphic functions.

In Caen he met his future wife, Louise Poulain d'Andecy (1857–1934), and on the 20th. April 1881, they married. Together they had four children: Jeanne (born 1887), Yvonne (born 1889), Henriette (born 1891), and Léon (born 1893).

Poincaré soon established himself as one of the greatest mathematicians of Europe. In 1881 he was invited to take a teaching position at the Faculty of Sciences of the University of Paris (the Sorbonne); he accepted the invitation, and for the rest of his career, he taught there. He was initially appointed as the associate professor of analysis. Eventually, he held the chairs of Physical and Experimental Mechanics, Mathematical Physics and Theory of Probability, and Celestial Mechanics and Astronomy.

In 1881–1882, Poincaré created a new branch of mathematics: qualitative theory of differential equations. He showed how it is possible to derive the most important information about the behavior of a family of solutions without having to solve the equation (since this may not always be possible). He successfully used this approach to problems in celestial mechanics and mathematical physics.

During the years 1883 to 1897, he taught mathematical analysis in the École Polytechnique.

-- Henri Poincaré's Career

Henri never fully abandoned his career in mining administration to mathematics. He worked at the Ministry of Public Services as an engineer in charge of northern railway development from 1881 to 1885. He eventually became chief engineer of the Corps des Mines in 1893, and inspector general in 1910.

In 1887, at the young age of 32, Poincaré was elected to the French Academy of Sciences. He became its president in 1906, and was elected to the Académie Française on the 5th. March 1908.

In 1887, he won the King of Sweden's mathematical competition for a resolution of the three-body problem concerning the free motion of multiple orbiting bodies.

In 1893, Poincaré joined the French Bureau des Longitudes, which engaged him in the synchronisation of time around the world. In 1897 Poincaré backed an unsuccessful proposal for the decimalisation of circular measure, and hence time and longitude.

It was this post which led him to consider the question of establishing international time zones and the synchronisation of time between bodies in relative motion.

In 1904, he intervened in the trial of Alfred Dreyfus, attacking the spurious scientific claims regarding evidence brought against Dreyfus.

Poincaré was the President of the Société Astronomique de France from 1901 to 1903.

-- The Death of Henri Poincaré

In 1912, Poincaré underwent surgery for a prostate problem and subsequently died from an embolism on the 17th. July 1912, in Paris. He was 58 years of age. He was laid to rest in the Poincaré family vault in the Cemetery of Montparnasse, Paris.

A former French Minister of Education, Claude Allègre, proposed in 2004 that Poincaré be reburied in the Panthéon in Paris, which is reserved for French citizens of the highest honour.

-- Overview of Henri Poincaré's Life

Poincaré made many contributions to different fields of pure and applied mathematics such as: celestial mechanics, fluid mechanics, optics, electricity, telegraphy, capillarity, elasticity, thermodynamics, potential theory, quantum theory, theory of relativity and physical cosmology.

He was also a populariser of mathematics and physics, and wrote several books for the lay public.

Among the specific topics to which he contributed are the following:

-- Algebraic topology (a field that Poincaré virtually invented)

-- The theory of analytic functions of several complex variables

-- The theory of abelian functions

-- Algebraic geometry

-- The Poincaré conjecture, proven in 2003 by Grigori Perelman

-- The Poincaré recurrence theorem

-- Hyperbolic geometry

-- Number theory

-- The three-body problem

-- The theory of diophantine equations

-- Electromagnetism

-- The special theory of relativity

-- The fundamental group

-- In the field of differential equations Poincaré has given many results that are critical for the qualitative theory of differential equations, for example the Poincaré sphere and the Poincaré map

-- Poincaré on "everybody's belief" in the Normal Law of Errors -- An influential paper providing a novel mathematical argument in support of quantum mechanics

-- Three-body problem. The problem of finding the general solution to the motion of more than two orbiting bodies in the Solar System had eluded mathematicians since Newton's time. This was known originally as the three-body problem, and later as the n-body problem, where n is any number of more than two orbiting bodies. The n-body solution was considered very important and challenging at the close of the 19th. century. Indeed, in 1887, in honour of his 60th. birthday, Oscar II, King of Sweden, established a prize for anyone who could find the solution to the problem. The announcement was quite specific:

'Given a system of mass points that attract each according to Newton's law, assuming that no two points ever collide, find a representation of the coordinates of each point as a series in a variable that is some known function of time and for all of whose values the series converges uniformly.'

In case the problem could not be solved, any other important contribution to classical mechanics would then be considered to be prize-worthy. The prize was finally awarded to Poincaré, even though he did not solve the original problem. One of the judges, the distinguished Karl Weierstrass, said:

"This work cannot indeed be considered as

furnishing the complete solution of the

question proposed, but it is nevertheless of

such importance that its publication will

inaugurate a new era in the history of celestial

mechanics."

Henri's contribution contained many important ideas which led to the theory of chaos. The problem as stated originally was finally solved by Karl F. Sundman for n = 3 in 1912, and was generalised to the case of n > 3 bodies by Qiudong Wang in the 1990's. The series solutions have very slow convergence. It would take millions of terms to determine the motion of the particles for even very short intervals of time, so they are unusable in numerical work.

-- Henri Poincaré's Work on Relativity

Poincaré's work at the Bureau des Longitudes on establishing international time zones led him to consider how clocks at rest on the Earth, which would be moving at different speeds relative to absolute space (aether), could be synchronised.

At the same time Dutch theorist Hendrik Lorentz was developing Maxwell's theory into a theory of the motion of charged particles ("electrons" or "ions"), and their interaction with radiation. In 1895 Lorentz had introduced an auxiliary quantity called "local time," and introduced the hypothesis of length contraction to explain the failure of optical and electrical experiments to detect motion relative to the aether.

Poincaré was a constant interpreter (and sometimes friendly critic) of Lorentz's theory. Poincaré as a philosopher was interested in the "deeper meaning". Thus he interpreted Lorentz's theory, and in so doing he came up with many insights that are now associated with special relativity.

In The Measure of Time (1898), Poincaré said:

"A little reflection is sufficient to understand

that all these affirmations have by themselves

no meaning. They can have one only as the

result of a convention."

He also argued that scientists have to set the constancy of the speed of light as a postulate to give physical theories the simplest form. Based on these assumptions he discussed in 1900 Lorentz's "wonderful invention" of local time, and remarked that it arose when moving clocks are synchronised by exchanging light signals assumed to travel with the same speed in both directions in a moving frame.

In 1892 Poincaré developed a mathematical theory of light including polarization. His vision of the action of polarizers and retarders, acting on a sphere representing polarized states, is called the Poincaré sphere. It was shown that the Poincaré sphere possesses an underlying Lorentzian symmetry, by which it can be used as a geometrical representation of Lorentz transformations and velocity additions.

Henri discussed the "principle of relative motion" in two papers in 1900, and named it the principle of relativity in 1904, according to which no physical experiment can discriminate between a state of uniform motion and a state of rest.

In 1905 Poincaré wrote to Lorentz about Lorentz's paper of 1904, which Poincaré described as:

"A paper of supreme importance".

In this letter he pointed out an error Lorentz had made when he had applied his transformation to one of Maxwell's equations i.e that for charge-occupied space. Henri also questioned the time dilation factor given by Lorentz.

In a second letter to Lorentz, Poincaré gave his own reason why Lorentz's time dilation factor was indeed correct after all—it was necessary to make the Lorentz transformation form a group—and he gave what is now known as the relativistic velocity-addition law.

-- The Mass–Energy Relation

Like others before, Poincaré (1900) discovered a relation between mass and electromagnetic energy. While studying the conflict between the action/reaction principle and the Lorentz ether theory, he tried to determine whether the center of gravity still moves with a uniform velocity when electromagnetic fields are included.

Henri noticed that the action/reaction principle does not hold for matter alone, but that the electromagnetic field has its own momentum. Poincaré concluded that the electromagnetic field energy of an electromagnetic wave behaves like a fictitious fluid with a mass density of E divided by c squared.

If the center of mass frame is defined by both the mass of matter and the mass of the fictitious fluid, and if the fictitious fluid is indestructible—it is neither created or destroyed—then the motion of the center of mass frame remains uniform.

However electromagnetic energy can be converted into other forms of energy, so Poincaré assumed that there exists a non-electric energy fluid at each point of space, into which electromagnetic energy can be transformed and which also carries a mass proportional to the energy.

In this way, the motion of the center of mass remains uniform. Poincaré said that one should not be too surprised by these assumptions, since they are only mathematical fictions.

However, Poincaré's resolution led to a paradox when changing frames: if a Hertzian oscillator radiates in a certain direction, it will suffer a recoil from the inertia of the fictitious fluid. Poincaré performed a Lorentz boost to the frame of the moving source.

He noted that energy conservation holds in both frames, but that the law of conservation of momentum is violated. This would allow perpetual motion, a notion which he abhorred. The laws of nature would have to be different in the frames of reference, and the relativity principle would not hold. Therefore, he argued that also in this case there has to be another compensating mechanism in the aether.

Poincaré himself came back to this topic in his St. Louis lecture (1904). He rejected the possibility that energy carries mass, and criticized his own solution to compensate the above-mentioned problems:

"The apparatus will recoil as if it were a cannon

and the projected energy a ball, and that

contradicts the principle of Newton, since our

present projectile has no mass; it is not matter,

it is energy.

Shall we say that the space which separates the

oscillator from the receiver and which the

disturbance must traverse in passing from one

to the other, is not empty, but is filled not only

with ether, but with air, or even in inter-planetary

space with some ethereal, yet ponderable fluid;

that this matter receives the shock, as does the

receiver, at the moment the energy reaches it,

and recoils, when the disturbance leaves it?

That would save Newton's principle, but it is not

true. If the energy during its propagation remained

always attached to some material substratum, this

matter would carry the light along with it, and

Fizeau has shown, at least for the air, that there is

nothing of the kind.

Michelson and Morley have since confirmed this.

We might also suppose that the motions of matter

proper were exactly compensated by those of the

aether; but that would lead us to the same

considerations as those made a moment ago.

The principle, if thus interpreted, could explain

anything, since whatever the visible motions, we

could imagine hypothetical motions to compensate

them.

But if it can explain anything, it will allow us to

foretell nothing; it will not allow us to choose

between the various possible hypotheses, since it

explains everything in advance.

It therefore becomes useless."

Henri refers to the Hertz assumption of total aether entrainment that was falsified by the Fizeau experiment, but that experiment does indeed show that that light is partially "carried along" with a substance.

Finally in 1908 Henri revisits the problem and ends with abandoning the principle of reaction altogether in favor of supporting a solution based in the inertia of aether itself.

Henri also discussed two other unexplained effects:

-- Non-conservation of mass implied by Kaufmann's experiments on the mass of fast moving electrons

-- The non-conservation of energy in the radium experiments of Marie Curie.

It was Albert Einstein's concept of mass–energy equivalence (1905) that a body losing energy as radiation or heat was losing mass of amount m = E/c2 that resolved Poincaré's paradox, without using any compensating mechanism within the ether.

The Hertzian oscillator loses mass in the emission process, and momentum is conserved in any frame. However, concerning Poincaré's solution of the Center of Gravity problem, Einstein noted that Poincaré's formulation and his own from 1906 were mathematically equivalent.

-- Gravitational Waves

In 1905 Poincaré first proposed gravitational waves emanating from a body and propagating at the speed of light. He wrote:

"It has become important to examine this hypothesis

more closely, and in particular to ask in what ways it

would require us to modify the laws of gravitation.

That is what I have tried to determine; at first I was

led to assume that the propagation of gravitation is

not instantaneous, but happens with the speed of

light."

-- Poincaré and Einstein

Einstein's first paper on relativity was published three months after Poincaré's short paper, but before Poincaré's longer version. Einstein relied on the principle of relativity to derive the Lorentz transformations, and used a similar clock synchronisation procedure (Einstein synchronisation) to the one that Poincaré (1900) had described, but Einstein's paper was remarkable in that it contained no references at all.

Poincaré never acknowledged Einstein's work on special relativity. However, Einstein expressed sympathy with Poincaré's outlook obliquely in a letter to Hans Vaihinger on the 3rd. May 1919, when Einstein considered Vaihinger's general outlook to be close to his own, and Poincaré's to be close to Vaihinger's.

In public, Einstein acknowledged Poincaré posthumously in the text of a lecture in 1921 titled "Geometry and Experience" in connection with non-Euclidean geometry, but not in connection with special relativity.

A few years before his death, Einstein commented on Poincaré as being one of the pioneers of relativity, saying:

"Lorentz had already recognized that the

transformation named after him is essential

for the analysis of Maxwell's equations, and

Poincaré deepened this insight still further."

-- Assessments of Poincaré and Relativity

Poincaré's work in the development of special relativity is well recognised, although most historians stress that despite many similarities with Einstein's work, the two had very different research agendas and interpretations of their work.

Poincaré developed a similar physical interpretation of local time and noticed the connection to signal velocity, but contrary to Einstein, he continued to use the aether concept in his papers, and argued that clocks at rest in the aether show the "true" time, and moving clocks show the local time.

So Poincaré tried to keep the relativity principle in accordance with classical concepts, while Einstein developed a mathematically equivalent kinematics based on the new physical concepts of the relativity of space and time.

While this is the view of most historians, a minority go much further, such as E. T. Whittaker, who held that Poincaré and Lorentz were the true discoverers of relativity.

-- Algebra and Number Theory

Poincaré introduced group theory to physics, and was the first to study the group of Lorentz transformations. He also made major contributions to the theory of discrete groups and their representations.

-- Topology

The subject is clearly defined by Felix Klein in his "Erlangen Program" (1872): the geometry invariants of arbitrary continuous transformation, a kind of geometry.

The term "topology" was introduced, as suggested by Johann Benedict Listing, instead of the previously used term "Analysis situs".

Some important concepts were introduced by Enrico Betti and Bernhard Riemann. But the foundation of this science, for a space of any dimension, was created by Poincaré. His first article on this topic appeared in 1894.

Henri's research in geometry led to the abstract topological definition of homotopy and homology. He also first introduced the basic concepts and invariants of combinatorial topology, such as Betti numbers and the fundamental group.

Poincaré proved a formula relating the number of edges, vertices and faces of an n-dimensional polyhedron (the Euler–Poincaré theorem), and gave the first precise formulation of the intuitive notion of dimension.

-- Astronomy and Celestial Mechanics

Poincaré published two classic monographs:

-- "New Methods of Celestial Mechanics" (1892–1899)

-- "Lectures on Celestial Mechanics" (1905–1910)

In them, he successfully applied the results of his research to the problem of the motion of three bodies, and studied in detail the behavior of solutions (frequency, stability, asymptotic, etc.). Poincaré introduced the small parameter method, fixed points, integral invariants, variational equations, the convergence of the asymptotic expansions.

Generalizing a theory of Bruns (1887), Poincaré showed that the three-body problem is not integrable. In other words, the general solution of the three-body problem can not be expressed in terms of algebraic and transcendental functions through unambiguous coordinates and velocities of the bodies. His work in this area was the first major achievement in celestial mechanics since Isaac Newton.

The two monographs include an idea of Poincaré, which later became the basis for mathematical "chaos theory" and the general theory of dynamical systems.

Poincaré authored important works on astronomy for the equilibrium figures of a gravitating rotating fluid. He introduced the important concept of bifurcation points, and proved the existence of equilibrium figures such as the non-ellipsoids, including ring-shaped and pear-shaped figures, and their stability.

For this discovery, Poincaré received the Gold Medal of the Royal Astronomical Society (1900).

-- Differential Equations and Mathematical Physics

After defending his doctoral thesis on the study of singular points of the system of differential equations, Poincaré wrote a series of memoirs under the title "On curves defined by differential equations" (1881–1882).

In these articles, he built a new branch of mathematics, called "qualitative theory of differential equations". Poincaré showed that even if the differential equation cannot be solved in terms of known functions, the very form of the equation provides a wealth of information about the properties and behavior of the solutions.

In particular, Poincaré investigated the nature of the trajectories of the integral curves in the plane, gave a classification of singular points (saddle, focus, center, node), introduced the concept of a limit cycle and loop index, and showed that the number of limit cycles is always finite, except for some special cases.

Poincaré also developed a general theory of integral invariants and solutions of the variational equations. For the finite-difference equations, he created a new direction – the asymptotic analysis of the solutions.

He applied all of these achievements to study practical problems of mathematical physics and celestial mechanics, and the methods used were the basis of its topological works.

Poincaré's work habits have been compared to a bee flying from flower to flower. Poincaré was interested in the way his mind worked; he studied his habits, and gave a talk about his observations in 1908 at the Institute of General Psychology in Paris. He linked his way of thinking to how he made several discoveries.

The mathematician Darboux claimed that Poincaré was un intuitif (an intuitive), arguing that this is demonstrated by the fact that he worked so often by visual representation.

Jacques Hadamard wrote that Poincaré's research demonstrated marvelous clarity, and Poincaré himself wrote that he believed that logic was not a way to invent, but a way to structure ideas, and that logic limits ideas.

The fact that renowned theoretical physicists like Poincaré, Boltzmann or Gibbs were not awarded the Nobel Prize is seen as evidence that the Nobel committee had more regard for experimentation than theory. In Poincaré's case, several of those who nominated him pointed out that the greatest problem was to name a specific discovery, invention, or technique.

-- Édouard Toulouse's Characterisation

Poincaré's mental organisation was interesting not only to Poincaré himself, but also to Édouard Toulouse, a psychologist based in Paris. Toulouse wrote a book entitled Henri Poincaré (1910). In it, he discussed Poincaré's regular schedule:

"He worked during the same times each day in

short periods of time. He undertook mathematical

research for four hours a day, between 10 a.m. and

noon, then again from 5 p.m. to 7 p.m.. He would

read articles in journals later in the evening.

His normal work habit was to solve a problem

completely in his head, then commit the completed

problem to paper.

He was ambidextrous and nearsighted.

His ability to visualise what he heard proved

particularly useful when he attended lectures, since

his eyesight was so poor that he could not see

properly what the lecturer wrote on the blackboard.

These abilities were offset to some extent by his shortcomings:

-- He was physically clumsy and artistically inept.

-- He was always in a rush, and disliked going back

for changes or corrections.

-- He never spent a long time on a problem since

he believed that the subconscious would continue

working on the problem while he consciously

worked on another problem.

In addition, Toulouse stated that most mathematicians worked from principles already established, while Poincaré started from basic principles each time (O'Connor et al., 2002).

His method of thinking is well summarised as:

"Accustomed to neglecting details and to looking

only at mountain tops, he went from one peak to

another with surprising rapidity, and the facts he

discovered, clustering around their center, were

instantly and automatically pigeonholed in his

memory."

— Belliver (1956).

-- Philosophy

Poincaré had philosophical views opposite to those of Bertrand Russell and Gottlob Frege, who believed that mathematics was a branch of logic. Poincaré strongly disagreed, claiming that intuition was the life of mathematics. Poincaré gives an interesting point of view in his 1902 book Science and Hypothesis:

"For a superficial observer, scientific truth is beyond

the possibility of doubt; the logic of science is infallible,

and if the scientists are sometimes mistaken, this is

only from their mistaking its rule."

Poincaré believed that arithmetic is synthetic. He argued that Peano's axioms cannot be proven non-circularly with the principle of induction (Murzi, 1998), therefore concluding that arithmetic is a priori synthetic and not analytic.

Poincaré then went on to say that mathematics cannot be deduced from logic since it is not analytic. His views were similar to those of Immanuel Kant. He strongly opposed Cantorian set theory, objecting to its use of impredicative definitions.

However, Poincaré did not share Kantian views in all branches of philosophy and mathematics. For example, in geometry, Poincaré believed that the structure of non-Euclidean space can be known analytically.

Poincaré held that convention plays an important role in physics. His view (and some later, more extreme versions of it) came to be known as "conventionalism". Poincaré believed that Newton's first law was not empirical, but is a conventional framework assumption for mechanics.

He also believed that the geometry of physical space is conventional. He considered examples in which either the geometry of the physical fields or gradients of temperature can be changed, either describing a space as non-Euclidean measured by rigid rulers, or as a Euclidean space where the rulers are expanded or shrunk by a variable heat distribution.

However, Poincaré thought that we were so accustomed to Euclidean geometry that we would prefer to change the physical laws to save Euclidean geometry rather than shift to a non-Euclidean physical geometry.

-- Free Will

Poincaré's famous lectures before the Société de Psychologie in Paris were cited by Jacques Hadamard as the source for the idea that creativity and invention consist of two mental stages, first random combinations of possible solutions to a problem, followed by a critical evaluation.

Although he most often spoke of a deterministic universe, Poincaré said that the subconscious generation of new possibilities involves chance.

"It is certain that the combinations which present

themselves to the mind in a kind of sudden

illumination after a somewhat prolonged period of unconscious work are generally useful and fruitful combinations... all the combinations are formed as

a result of the automatic action of the subliminal

ego, but those only which are interesting find their

way into the field of consciousness.

A few only are harmonious, and consequently at

once useful and beautiful, and they will be capable

of affecting the geometrician's special sensibility

I have been speaking of; which, once aroused, will

direct our attention upon them, and will thus give

them the opportunity of becoming conscious.

In the subliminal ego, on the contrary, there reigns

what I would call liberty, if one could give this name

to the mere absence of discipline and to disorder

born of chance."

Poincaré's two stages—random combinations followed by selection—became the basis for Daniel Dennett's two-stage model of free will.

EICO 377 top by johngineer

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blog post: www.johngineer.com/blog/?p=1193

751.001 Rakšice, 07/07/17 by Richard Jones

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751.001 (T478.1001) at Oslavany, Grumpy Railtours "The Oslavany Oscillator", Zvl R 10063 1035 Oslavany - Rakšice, 07/07/17

The Glorious Kostromo by Matt Jones

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My entry for Weta's Rightous Bison Customization Contest over at The RPF

Phew! Got it sent in at the very last second; worked RIGHT up to the wire. Hopefully you like. The light up bits are actual Soviet neon tubes (like nixies) and took far more time than I'd expected to get running properly. Still have bugs. The farther you pull back the trigger, the faster the Dekatron on the back spins, and the more the bar graph tubes on the sides fill up with light.

The Glorious Kostromo. The United Republics of the Red Star got a hold of the original Bison, and had at the design, streamlining and instilling typical Russian reliability and brute force into a design that originally lacked them (though it made up for it with character!) This particular instance originally received the winter paintjob, though it's now gone to rust, and rests on a ceremonial Republic display stand.

751.001 Oslavany, 07/07/17 by Richard Jones

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