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After getting ribbings for my elaborate monitor setup, I posted this pic to my old gaming forum after photoshopping a few extra monitors into the mix.
These arrived today from B&H to review, pretty sure two will be going back and one will become my new monitor after I am done with the review. My existing Samsung monitor is 7 years old.
I repaired the ViewSonic monitor on the right by replacing about a half-dozen capacitors.
The parts cost about $15; the whole process took about 2 hours.
Learn more about this kind of repair at badcaps.org.
Some more details in the next photo.
Water monitors are a species of reptile very common in some areas of Southeast Asia. With their extra large size (up to 3 metres) they are unlikely to go unnoticed.
This paper model is a Monzir Monitor, a fighter from the game The Tomorrow War, the papercraft is created by [unknown]. The size of finished model is about 150 (H) x 178 (W) x 82 (D) mm.
You can download the papercraft model here: Tomorrow War - Monzir Monitor Free Paper Model Download [DropBox] ...
www.papercraftsquare.com/tomorrow-war-monzir-monitor-free...
Dell 2407 monitor pixels - blur due to not using tripod.
Nikon D610 - Zhongyi Mitakon 20mm f/2.0 4.5X Super Macro Lens
NeXT 21-inch Megapixel colour monitor. It worked fine (bright, sharp) up to the day it suddenly died. As the light in the on/off button died as well, I suspect that the power source (a low tech part and I guess the easiest to repair) is broken.
A Beautiful Mertens Water monitor taken in Litchfield National Park NT. Was very friendly and had little fear of my wife and I
Katubedda, Sri Lanka.
Does anyone know if this is a male-male fight for dominance or a male-female mating ritual?
Photoshop across 3 monitors, 3984x1050 res. 2 seperate 3 exposures +-2 stop, both hdred then stitched in photo shop,
Western Chieftain rumbles through Exeter on 6M55 past Western Monitor which, despite the headcode, is on 1Z75, The Atlantic Coast Express railtour. Unable to fit the splendid headboard seen on 25244 in the previous posting, a hastily improvised replacement was provided ! Don't look too close at this as some heavy neg scan repair was required! I hope it's worthy of posting nonetheless, if only for the 'smiley face' on 'Chieftain' and the steam powered cine camera sported by the gent on the right!
Police monitoring a protest outside the former Legco Building in Central Hong Kong in 1987. In those days anything worth recording was done so in long-hand in a notebook. They were also playing it safe with as many officers present as protesters. It's important to get a policeman to look at you (preferably with menace) when you're photographing him: see here for another example 27 years later www.flickr.com/photos/steventhompson38/14550521935/in/pho...
The average American teenager sends an average in excess of 100 SMS text messages every day. A shocking 20 % of teenagers admit they have sent or posted nude or seminude 'zexting' images, possibly a serious zex crime. Eighty percent of all car crashes in the United States involve distracted drivers, destroying the lives of thousands of teenagers each year.
Parents are responsible to both defend their kids, and to discover what they are doing, and where they are doing it. Checking kids can be done easily and fairly. Keep in mind that tracking and monitoring of devices should include computers, smartphones and tablets.
Many spy phone software programs are especially refined and made available by reasonably reliable companies; however sadly the great majority of offers come from unsecured sellers or other types of shady characters making false promises. Monitoring software is a basic term for the various types of plans widely available to be able to document personal computer or smartphone activity. Meanings vary depending upon use and objective of spy phone applications as opposed to a technical classification. There are a variety of methods used by coders in designing spyware, used on cell phones also called spyphone software.
Many people may use spy in their terminology when they refer to valid monitoring of cell phones. There are a lot of valid reasons to Track Cell Phone and communications content.
Not only is Parental Monitoring acceptable, and Employee Monitoring acceptable, they are mandated. If not legally, then morally and ethically; given that parents and employers are empowered to moderate tragedy and liability that originate from cell phone misuse or the need for protection. Authority comes with accountability. On the plus side there is something to keep in mind is usually that spy phone software packages require authorization. A number of spy phone software packages can be sent to the phone remotely, yet are unable to be installed or activated. Staff Monitoring responsibility goes beyond productivity and policy compliance; guarding against insider threats and other misuse is very important and Cyberbullying and zexual Harassment remain considerable issues for companies. Employers, Parents and just about anyone rely on cell phone spy phone software programs to get a handle on data loss prevention, when in case their phones are lost or stolen. Parental responsibly means knowing where kids are and what they are doing with their phones and computers. Parental Monitoring Youth Cell phone Usage: Parents and guardians use cell phone spy phone software programs to get a handle on distracted drivers, zexting, predators, excessive use.
File name: 10_03_001609b
Binder label: Agriculture
Title: Monitor Rake (back)
Created/Published: Buffalo, N. Y. : Gies & Co.
Date issued: 1870-1900 (approximate)
Physical description: 1 print : chromolithograph ; 17 x 11 cm.
Genre: Advertising cards
Subject: Men; Horses; Agricultural equipment
Notes: Title from item. Retailer: J. Herbert Seavey, Dover, N. H.
Statement of responsibility: Higganum Manufacturing Corporation
Collection: 19th Century American Trade Cards
Location: Boston Public Library, Print Department
Rights: No known restrictions.
I have been tagged by kiwigirlerinm
Three things about me.
1. I am staying up way too late flickring.
2. The computer monitor is reflected in my eyes, I fear that they may stay that way forever.
3. I rarely post a self portrait, unless hiding behind a camera. The last shot I did when tagged, I deleted. This one will most likely have the same fate.
I tag:
Things to do for Tag:
1 - Stop what you're doing.
2 - TAKE A PICTURE OF YOURSELF RIGHT NOW. Don't primp, just snap one!
3 -Upload it.
4. Share 3 things about yourself
5 - Tag 5 people to do the same (name check in your comment and/or send flickrmail)
For Fun.
The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.
Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."
As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.
Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.
Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.
ETYMOLOGY
The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).
EVOLUTIONARY HISTORY
The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.
DESCRIPTION
In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.
SENSES
As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.
The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.
The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.
BEHAVIOUR AND ECOLOGY
The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.
For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.
DIET
Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.
Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.
The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.
The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.
The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.
SALIVA
Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.
VENOM
In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.
In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.
Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.
Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".
REPRODUCTION
Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.
PARTHENOGENESIS
A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.
Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.
It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.
HISTORY
DISCOVERY BY THE WESTERN WORLD
Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.
STUDIES
The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.
CONSERVATION
The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.
Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.
Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.
On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.
IN CAPTIVITY
Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.
The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.
A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".
Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.
IN POPULARE CULTURE
Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).
The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."
The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.
In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.
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Patent US6506148 - Nervous system manipulation by electromagnetic fields from monitors
Publication number US6506148 B2
Publication type Grant
Application number US 09/872,528
Publication date Jan 14, 2003
Filing date Jun 1, 2001
Priority date Jun 1, 2001
Fee status Paid
Also published as US20020188164
Inventors Hendricus G. Loos
Original Assignee Hendricus G. Loos
Export Citation BiBTeX, EndNote, RefMan
Patent Citations (16), Non-Patent Citations (5), Referenced by (3), Classifications (6), Legal Events (3)
External Links: USPTO, USPTO Assignment, Espacenet
Nervous system manipulation by electromagnetic fields from monitors
US 6506148 B2
Abstract
Physiological effects have been observed in a human subject in response to stimulation of the skin with weak electromagnetic fields that are pulsed with certain frequencies near ½ Hz or 2.4 Hz, such as to excite a sensory resonance. Many computer monitors and TV tubes, when displaying pulsed images, emit pulsed electromagnetic fields of sufficient amplitudes to cause such excitation. It is therefore possible to manipulate the nervous system of a subject by pulsing images displayed on a nearby computer monitor or TV set. For the latter, the image pulsing may be imbedded in the program material, or it may be overlaid by modulating a video stream, either as an RF signal or as a video signal. The image displayed on a computer monitor may be pulsed effectively by a simple computer program. For certain monitors, pulsed electromagnetic fields capable of exciting sensory resonances in nearby subjects may be generated even as the displayed images are pulsed with subliminal intensity.
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Claims(14)
I claim:
1. A method for manipulating the nervous system of a subject located near a monitor, the monitor emitting an electromagnetic field when displaying an image by virtue of the physical display process, the subject having a sensory resonance frequency, the method comprising:
creating a video signal for displaying an image on the monitor, the image having an intensity;
modulating the video signal for pulsing the image intensity with a frequency in the range 0.1 Hz to 15 Hz; and
setting the pulse frequency to the resonance frequency.
2. A computer program for manipulating the nervous system of a subject located near a monitor, the monitor emitting an electromagnetic field when displaying an image by virtue of the physical display process, the subject having cutaneous nerves that fire spontaneously and have spiking patterns, the computer program comprising:
a display routine for displaying an image on the monitor, the image having an intensity;
a pulse routine for pulsing the image intensity with a frequency in the range 0.1 Hz to 15 Hz; and
a frequency routine that can be internally controlled by the subject, for setting the frequency;
whereby the emitted electromagnetic field is pulsed, the cutaneous nerves are exposed to the pulsed electromagnetic field, and the spiking patterns of the nerves acquire a frequency modulation.
3. The computer program of claim 2, wherein the pulsing has an amplitude and the program further comprises an amplitude routine for control of the amplitude by the subject.
4. The computer program of claim 2, wherein the pulse routine comprises:
a timing procedure for timing the pulsing; and
an extrapolation procedure for improving the accuracy of the timing procedure.
5. The computer program of claim 2, further comprising a variability routine for introducing variability in the pulsing.
6. Hardware means for manipulating the nervous system of a subject located near a monitor, the monitor being responsive to a video stream and emitting an electromagnetic field when displaying an image by virtue of the physical display process, the image having an intensity, the subject having cutaneous nerves that fire spontaneously and have spiking patterns, the hardware means comprising:
pulse generator for generating voltage pulses;
means, responsive to the voltage pulses, for modulating the video stream to pulse the image intensity;
whereby the emitted electromagnetic field is pulsed, the cutaneous nerves are exposed to the pulsed electromagnetic field, and the spiking patterns of the nerves acquire a frequency modulation.
7. The hardware means of claim 6, wherein the video stream is a composite video signal that has a pseudo-dc level, and the means for modulating the video stream comprise means for pulsing the pseudo-dc level.
8. The hardware means of claim 6, wherein the video stream is a television broadcast signal, and the means for modulating the video stream comprise means for frequency wobbling of the television broadcast signal.
9. The hardware means of claim 6, wherein the monitor has a brightness adjustment terminal, and the means for modulating the video stream comprise a connection from the pulse generator to the brightness adjustment terminal.
10. A source of video stream for manipulating the nervous system of a subject located near a monitor, the monitor emitting an electromagnetic field when displaying an image by virtue of the physical display process, the subject having cutaneous nerves that fire spontaneously and have spiking patterns, the source of video stream comprising:
means for defining an image on the monitor, the image having an intensity; and
means for subliminally pulsing the image intensity with a frequency in the range 0.1 Hz to 15 Hz;
whereby the emitted electromagnetic field is pulsed, the cutaneous nerves are exposed to the pulsed electromagnetic field, and the spiking patterns of the nerves acquire a frequency modulation.
11. The source of video stream of claim 10 wherein the source is a recording medium that has recorded data, and the means for subliminally pulsing the image intensity comprise an attribute of the recorded data.
12. The source of video stream of claim 10 wherein the source is a computer program, and the means for subliminally pulsing the image intensity comprise a pulse routine.
13. The source of video stream of claim 10 wherein the source is a recording of a physical scene, and the means for subliminally pulsing the image intensity comprise:
pulse generator for generating voltage pulses;
light source for illuminating the scene, the light source having a power level; and
modulation means, responsive to the voltage pulses, for pulsing the power level.
14. The source of video stream of claim 10, wherein the source is a DVD, the video stream comprises a luminance signal and a chrominance signal, and the means for subliminal pulsing of the image intensity comprise means for pulsing the luminance signal.
Description
BACKGROUND OF THE INVENTION
The invention relates to the stimulation of the human nervous system by an electromagnetic field applied externally to the body. A neurological effect of external electric fields has been mentioned by Wiener (1958), in a discussion of the bunching of brain waves through nonlinear interactions. The electric field was arranged to provide “a direct electrical driving of the brain”. Wiener describes the field as set up by a 10 Hz alternating voltage of 400 V applied in a room between ceiling and ground. Brennan (1992) describes in U.S. Pat. No. 5,169,380 an apparatus for alleviating disruptions in circadian rythms of a mammal, in which an alternating electric field is applied across the head of the subject by two electrodes placed a short distance from the skin.
A device involving a field electrode as well as a contact electrode is the “Graham Potentializer” mentioned by Hutchison (1991). This relaxation device uses motion, light and sound as well as an alternating electric field applied mainly to the head. The contact electrode is a metal bar in Ohmic contact with the bare feet of the subject, and the field electrode is a hemispherical metal headpiece placed several inches from the subject's head.
In these three electric stimulation methods the external electric field is applied predominantly to the head, so that electric currents are induced in the brain in the physical manner governed by electrodynamics. Such currents can be largely avoided by applying the field not to the head, but rather to skin areas away from the head. Certain cutaneous receptors may then be stimulated and they would provide a signal input into the brain along the natural pathways of afferent nerves. It has been found that, indeed, physiological effects can be induced in this manner by very weak electric fields, if they are pulsed with a frequency near ½ Hz. The observed effects include ptosis of the eyelids, relaxation, drowziness, the feeling of pressure at a centered spot on the lower edge of the brow, seeing moving patterns of dark purple and greenish yellow with the eyes closed, a tonic smile, a tense feeling in the stomach, sudden loose stool, and sexual excitement, depending on the precise frequency used, and the skin area to which the field is applied. The sharp frequency dependence suggests involvement of a resonance mechanism.
It has been found that the resonance can be excited not only by externally applied pulsed electric fields, as discussed in U.S. Pat. Nos. 5,782,874, 5,899,922, 6,081,744, and 6,167,304, but also by pulsed magnetic fields, as described in U.S. Pat. Nos. 5,935,054 and 6,238,333, by weak heat pulses applied to the skin, as discussed in U.S. Pat. Nos. 5,800,481 and 6,091,994, and by subliminal acoustic pulses, as described in U.S. Pat. No. 6,017,302. Since the resonance is excited through sensory pathways, it is called a sensory resonance. In addition to the resonance near ½ Hz, a sensory resonance has been found near 2.4 Hz. The latter is characterized by the slowing of certain cortical processes, as discussed in the '481, '922, '302, '744, '944, and '304 patents.
The excitation of sensory resonances through weak heat pulses applied to the skin provides a clue about what is going on neurologically. Cutaneous temperature-sensing receptors are known to fire spontaneously. These nerves spike somewhat randomly around an average rate that depends on skin temperature. Weak heat pulses delivered to the skin in periodic fashion will therefore cause a slight frequency modulation (fm) in the spike patterns generated by the nerves. Since stimulation through other sensory modalities results in similar physiological effects, it is believed that frequency modulation of spontaneous afferent neural spiking patterns occurs there as well.
It is instructive to apply this notion to the stimulation by weak electric field pulses administered to the skin. The externally generated fields induce electric current pulses in the underlying tissue, but the current density is much too small for firing an otherwise quiescent nerve. However, in experiments with adapting stretch receptors of the crayfish, Terzuolo and Bullock (1956) have observed that very small electric fields can suffice for modulating the firing of already active nerves. Such a modulation may occur in the electric field stimulation under discussion.
Further understanding may be gained by considering the electric charges that accumulate on the skin as a result of the induced tissue currents. Ignoring thermodynamics, one would expect the accumulated polarization charges to be confined strictly to the outer surface of the skin. But charge density is caused by a slight excess in positive or negative ions, and thermal motion distributes the ions through a thin layer. This implies that the externally applied electric field actually penetrates a short distance into the tissue, instead of stopping abruptly at the outer skin surface. In this manner a considerable fraction of the applied field may be brought to bear on some cutaneous nerve endings, so that a slight modulation of the type noted by Terzuolo and Bullock may indeed occur.
The mentioned physiological effects are observed only when the strength of the electric field on the skin lies in a certain range, called the effective intensity window. There also is a bulk effect, in that weaker fields suffice when the field is applied to a larger skin area. These effects are discussed in detail in the '922 patent.
Since the spontaneous spiking of the nerves is rather random and the frequency modulation induced by the pulsed field is very shallow, the signal to noise ratio (S/N) for the fm signal contained in the spike trains along the afferent nerves is so small as to make recovery of the fm signal from a single nerve fiber impossibile. But application of the field over a large skin area causes simultaneous stimulation of many cutaneous nerves, and the fm modulation is then coherent from nerve to nerve. Therefore, if the afferent signals are somehow summed in the brain, the fm modulations add while the spikes from different nerves mix and interlace. In this manner the S/N can be increased by appropriate neural processing. The matter is discussed in detail in the '874 patent. Another increase in sensitivity is due to involving a resonance mechanism, wherein considerable neural circuit oscillations can result from weak excitations.
An easily detectable physiological effect of an excited ½ Hz sensory resonance is ptosis of the eyelids. As discussed in the '922 patent, the ptosis test involves first closing the eyes about half way. Holding this eyelid position, the eyes are rolled upward, while giving up voluntary control of the eyelids. The eyelid position is then determined by the state of the autonomic nervous system. Furthermore, the pressure excerted on the eyeballs by the partially closed eyelids increases parasympathetic activity. The eyelid position thereby becomes somewhat labile, as manifested by a slight flutter. The labile state is sensitive to very small shifts in autonomic state. The ptosis influences the extent to which the pupil is hooded by the eyelid, and thus how much light is admitted to the eye. Hence, the depth of the ptosis is seen by the subject, and can be graded on a scale from 0 to 10.
In the initial stages of the excitation of the ½ Hz sensory resonance, a downward drift is detected in the ptosis frequency, defined as the stimulation frequency for which maximum ptosis is obtained. This drift is believed to be caused by changes in the chemical milieu of the resonating neural circuits. It is thought that the resonance causes perturbations of chemical concentrations somewhere in the brain, and that these perturbations spread by diffusion to nearby resonating circuits. This effect, called “chemical detuning”, can be so strong that ptosis is lost altogether when the stimulation frequency is kept constant in the initial stages of the excitation. Since the stimulation then falls somewhat out of tune, the resonance decreases in amplitude and chemical detuning eventually diminishes. This causes the ptosis frequency to shift back up, so that the stimulation is more in tune and the ptosis can develop again. As a result, for fixed stimulation frequencies in a certain range, the ptosis slowly cycles with a frequency of several minutes. The matter is discussed in the '302 patent.
The stimulation frequencies at which specific physiological effects occur depend somewhat on the autonomic nervous system state, and probably on the endocrine state as well.
Weak magnetic fields that are pulsed with a sensory resonance frequency can induce the same physiological effects as pulsed electric fields. Unlike the latter however, the magnetic fields penetrate biological tissue with nearly undiminished strength. Eddy currents in the tissue drive electric charges to the skin, where the charge distributions are subject to thermal smearing in much the same way as in electric field stimulation, so that the same physiological effects develop. Details are discussed in the '054 patent.
SUMMARY
Computer monotors and TV monitors can be made to emit weak low-frequency electromagnetic fields merely by pulsing the intensity of displayed images. Experiments have shown that the ½ Hz sensory resonance can be excited in this manner in a subject near the monitor. The 2.4 Hz sensory resonance can also be excited in this fashion. Hence, a TV monitor or computer monitor can be used to manipulate the nervous system of nearby people.
The implementations of the invention are adapted to the source of video stream that drives the monitor, be it a computer program, a TV broadcast, a video tape or a digital video disc (DVD).
For a computer monitor, the image pulses can be produced by a suitable computer program. The pulse frequency may be controlled through keyboard input, so that the subject can tune to an individual sensory resonance frequency. The pulse amplitude can be controlled as well in this manner. A program written in Visual Basic(R) is particularly suitable for use on computers that run the Windows 95(R) or Windows 98(R) operating system. The structure of such a program is described. Production of periodic pulses requires an accurate timing procedure. Such a procedure is constructed from the GetTimeCount function available in the Application Program Interface (API) of the Windows operating system, together with an extrapolation procedure that improves the timing accuracy.
Pulse variability can be introduced through software, for the purpose of thwarting habituation of the nervous system to the field stimulation, or when the precise resonance frequency is not known. The variability may be a pseudo-random variation within a narrow interval, or it can take the form of a frequency or amplitude sweep in time. The pulse variability may be under control of the subject.
The program that causes a monitor to display a pulsing image may be run on a remote computer that is connected to the user computer by a link; the latter may partly belong to a network, which may be the Internet.
For a TV monitor, the image pulsing may be inherent in the video stream as it flows from the video source, or else the stream may be modulated such as to overlay the pulsing. In the first case, a live TV broadcast can be arranged to have the feature imbedded simply by slightly pulsing the illumination of the scene that is being broadcast. This method can of course also be used in making movies and recording video tapes and DVDs.
Video tapes can be edited such as to overlay the pulsing by means of modulating hardware. A simple modulator is discussed wherein the luminance signal of composite video is pulsed without affecting the chroma signal. The same effect may be introduced at the consumer end, by modulating the video stream that is produced by the video source. A DVD can be edited through software, by introducing pulse-like variations in the digital RGB signals. Image intensity pulses can be overlaid onto the analog component video output of a DVD player by modulating the luminance signal component. Before entering the TV set, a television signal can be modulated such as to cause pulsing of the image intensity by means of a variable delay line that is connected to a pulse generator.
Certain monitors can emit electromagnetic field pulses that excite a sensory resonance in a nearby subject, through image pulses that are so weak as to be subliminal. This is unfortunate since it opens a way for mischievous application of the invention, whereby people are exposed unknowingly to manipulation of their nervous systems for someone else's purposes. Such application would be unethical and is of course not advocated. It is mentioned here in order to alert the public to the possibility of covert abuse that may occur while being online, or while watching TV, a video, or a DVD.
DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the electromagnetic field that emanates from a monitor when the video signal is modulated such as to cause pulses in image intensity, and a nearby subject who is exposed to the field.
FIG. 2 shows a circuit for modulation of a composite video signal for the purpose of pulsing the image intensity.
FIG. 3 shows the circuit for a simple pulse generator.
FIG. 4 illustrates how a pulsed electromagnetic field can be generated with a computer monitor.
FIG. 5 shows a pulsed electromagnetic field that is generated by a television set through modulation of the RF signal input to the TV.
FIG. 6 outlines the structure of a computer program for producing a pulsed image.
FIG. 7 shows an extrapolation procedure introduced for improving timing accuracy of the program of FIG. 6.
FIG. 8 illustrates the action of the extrapolation procedure of FIG. 7.
FIG. 9 shows a subject exposed to a pulsed electromagnetic field emanating from a monitor which is responsive to a program running on a remote computer via a link that involves the Internet.
FIG. 10 shows the block diagram of a circuit for frequency wobbling of a TV signal for the purpose of pulsing the intensity of the image displayed on a TV monitor.
FIG. 11 depicts schematically a recording medium in the form of a video tape with recorded data, and the attribute of the signal that causes the intensity of the displayed image to be pulsed.
FIG. 12 illustrates how image pulsing can be embedded in a video signal by pulsing the illumination of the scene that is being recorded.
FIG. 13 shows a routine that introduces pulse variability into the computer program of FIG. 6.
FIG. 14 shows schematically how a CRT emits an electromagnetic field when the displayed image is pulsed.
FIG. 15 shows how the intensity of the image displayed on a monitor can be pulsed through the brightness control terminal of the monitor.
FIG. 16 illustrates the action of the polarization disc that serves as a model for grounded conductors in the back of a CRT screen.
FIG. 17 shows the circuit for overlaying image intensity pulses on a DVD output.
FIG. 18 shows measured data for pulsed electric fields emitted by two different CRT type monitors, and a comparison with theory.
DETAILED DESCRIPTION
Computer monitors and TV monitors emit electromagnetic fields. Part of the emission occurs at the low frequencies at which displayed images are changing. For instance, a rythmic pulsing of the intensity of an image causes electromagnetic field emission at the pulse frequency, with a strength proportional to the pulse amplitude. The field is briefly referred to as “screen emission”. In discussing this effect, any part or all what is displayed on the monitor screen is called an image. A monitor of the cathode ray tube (CRT) type has three electron beams, one for each of the basic colors red, green, and blue. The intensity of an image is here defined as
I=∫j dA, (1)
where the integral extends over the image, and
j=jr+jg+jb, (2)
jr, jg, and jb being the electric current densities in the red, green, and blue electron beams at the surface area dA of the image on the screen. The current densities are to be taken in the distributed electron beam model, where the discreteness of pixels and the raster motion of the beams are ignored, and the back of the monitor screen is thought to be irradiated by diffuse electron beams. The beam current densities are then functions of the coordinates x and y over the screen. The model is appropriate since we are interested in the electromagnetic field emision caused by image pulsing with the very low frequencies of sensory resonances, whereas the emissions with the much higher horizontal and vertical sweep frequencies are of no concern. For a CRT the intensity of an image is expressed in millamperes.
For a liquid crystal display (LCD), the current densities in the definition of image intensity are to be replaced by driving voltages, multiplied by the aperture ratio of the device. For an LCD, image intensities are thus expressed in volts.
It will be shown that for a CRT or LCD screen emissions are caused by fluctuations in image intensity. In composite video however, intensity as defined above is not a primary signal feature, but luminance Y is. For any pixel one has
Y=0.299R+0.587G+0.114B, (3)
where R, G, and B are the intensities of the pixel respectively in red, green and blue, normalized such as to range from 0 to 1. The definition (3) was provided by the Commission Internationale de l'Eclairage (CIE), in order to account for brightness differences at different colors, as perceived by the human visual system. In composite video the hue of the pixel is determined by the chroma signal or chrominance, which has the components R-Y and B-Y It follows that pulsing pixel luminance while keeping the hue fixed is equivalent to pulsing the pixel intensity, up to an amplitude factor. This fact will be relied upon when modulating a video stream such as to overlay image intensity pulses.
It turns out that the screen emission has a multipole expansion wherein both monopole and dipole contributions are proportional to the rate of change of the intensity I of (1). The higher order multipole contributions are proportional to the rate of change of moments of the current density j over the image, but since these contributions fall off rapidly with distance, they are not of practical importance in the present context. Pulsing the intensity of an image may involve different pulse amplitudes, frequencies, or phases for different parts of the image. Any or all of these features may be under subject control.
The question arises whether the screen emission can be strong enough to excite sensory resonances in people located at normal viewing distances from the monitor. This turns out to be the case, as shown by sensory resonance experiments and independently by measuring the strength of the emitted electric field pulses and comparing the results with the effective intensity window as explored in earlier work.
One-half Hertz sensory resonance experiments have been conducted with the subject positioned at least at normal viewing distance from a 15″ computer monitor that was driven by a computer program written in Visual Basic(R), version 6.0 (VB6). The program produces a pulsed image with uniform luminance and hue over the full screen, except for a few small control buttons and text boxes. In VB6, screen pixel colors are determined by integers R, G, and B, that range from 0 to 255, and set the contributions to the pixel color made by the basic colors red, green, and blue. For a CRT-type monitor, the pixel intensities for the primary colors may depend on the RGB values in a nonlinear manner that will be discussed. In the VB6 program the RGB values are modulated by small pulses ΔR, ΔG, ΔB, with a frequency that can be chosen by the subject or is swept in a predetermined manner. In the sensory resonance experiments mentioned above, the ratios ΔR/R, ΔG/G, and ΔB/B were always smaller than 0.02, so that the image pulses are quite weak. For certain frequencies near ½ Hz, the subject experienced physiological effects that are known to accompany the excitation of the ½ Hz sensory resonance as mentioned in the Background Section. Moreover, the measured field pulse amplitudes fall within the effective intensity window for the ½ Hz resonance, as explored in earlier experiments and discussed in the '874, '744, '922, and '304 patents. Other experiments have shown that the 2.4 Hz sensory resonance can be exited as well by screen emissions from monitors that display pulsed images.
These results confirm that, indeed, the nervous system of a subject can be manipulated through electromagnetic field pulses emitted by a nearby CRT or LCD monitor which displays images with pulsed intensity.
The various implementations of the invention are adapted to the different sources of video stream, such as video tape, DVD, a computer program, or a TV broadcast through free space or cable. In all of these implementations, the subject is exposed to the pulsed electromagnetic field that is generated by the monitor as the result of image intensity pulsing. Certain cutaneous nerves of the subject exhibit spontaneous spiking in patterns which, although rather random, contain sensory information at least in the form of average frequency. Some of these nerves have receptors that respond to the field stimulation by changing their average spiking frequency, so that the spiking patterns of these nerves acquire a frequency modulation, which is conveyed to the brain. The modulation can be particularly effective if it has a frequency at or near a sensory resonance frequency. Such frequencies are expected to lie in the range from 0.1 to 15 Hz.
An embodiment of the invention adapted to a VCR is shown in FIG. 1, where a subject 4 is exposed to a pulsed electric field 3 and a pulsed magnetic field 39 that are emitted by a monitor 2, labeled “MON”, as the result of pulsing the intensity of the displayed image. The image is here generated by a video casette recorder 1, labeled “VCR”, and the pulsing of the image intensity is obtained by modulating the composite video signal from the VCR output. This is done by a video modulator 5, labeled “VM”, which responds to the signal from the pulse generator 6, labeled “GEN”. The frequency and amplitude of the image pulses can be adjusted with the frequency control 7 and amplitude control 8. Frequency and amplitude adjustments can be made by the subject.
The circuit of the video modulator 5 of FIG. 1 is shown in FIG. 2, where the video amplifiers 11 and 12 process the composite video signal that enters at the input terminal 13. The level of the video signal is modulated slowly by injecting a small bias current at the inverting input 17 of the first amplifier 11. This current is caused by voltage pulses supplied at the modulation input 16, and can be adjusted through the potentiometer 15. Since the noninverting input of the amplifier is grounded, the inverting input 17 is kept essentially at ground potential, so that the bias current is is not influenced by the video signal. The inversion of the signal by the first amplifier 11 is undone by the second amplifier 12. The gains of the amplifiers are chosen such as to give a unity overall gain. A slowly varying current injected at the inverting input 17 causes a slow shift in the “pseudo-dc” level of the composite video signal, here defined as the short-term average of the signal. Since the pseudo-dc level of the chroma signal section determines the luminance, the latter is modulated by the injected current pulses. The chroma signal is not affected by the slow modulation of the pseudodc level, since that signal is determined by the amplitude and phase with respect to the color carrier which is locked to the color burst. The effect on the sync pulses and color bursts is of no consequence either if the injected current pulses are very small, as they are in practice. The modulated composite video signal, available at the output 14 in FIG. 2, will thus exhibit a modulated luminance, whereas the chroma signal is unchanged. In the light of the foregoing discussion about luminance and intensity, it follows that the modulator of FIG. 2 causes a pulsing of the image intensity I. It remains to give an example how the pulse signal at the modulation input 16 may be obtained. FIG. 3 shows a pulse generator that is suitable for this purpose, wherein the RC timer 21 (Intersil ICM7555) is hooked up for astable operation and produces a square wave voltage with a frequency that is determined by capacitor 22 and potentiometer 23. The timer 21 is powered by a battery 26, controlled by the switch 27. The square wave voltage at output 25 drives the LED 24, which may be used for monitoring of the pulse frequency, and also serves as power indicator. The pulse output may be rounded in ways that are well known in the art. In the setup of FIG. 1, the output of VCR 1 is connected to the video input 13 of FIG. 2, and the video output 14 is connected to the monitor 2 of FIG. 1.
In the preferred embodiment of the invention, the image intensity pulsing is caused by a computer program. As shown in FIG. 4, monitor 2, labeled “MON”, is connected to computer 31 labeled “COMPUTER”, which runs a program that produces an image on the monitor and causes the image intensity to be pulsed. The subject 4 can provide input to the computer through the keyboard 32 that is connected to the computer by the connection 33. This input may involve adjustments of the frequency or the amplitude or the variability of the image intensity pulses. In particular, the pulse frequency can be set to a sensory resonance frequency of the subject for the purpose of exciting the resonance.
The structure of a computer program for pulsing image intensity is shown in FIG. 6. The program may be written in Visual Basic(R) version 6.0 (VB6), which involves the graphics interface familiar from the Windows(R) operating system. The images appear as forms equipped with user controls such as command buttons and scroll bars, together with data displays such as text boxes. A compiled VB6 program is an executable file. When activated, the program declares variables and functions to be called from a dynamic link library (DLL) that is attached to the operating system; an initial form load is performed as well. The latter comprises setting the screen color as specified by integers R, G, and B in the range 0 to 255, as mentioned above. In FIG. 6, the initial setting of the screen color is labeled as 50. Another action of the form load routine is the computation 51 of the sine function at eight equally spaced points, I=0 to 7, around the unit circle. These values are needed when modulating the RGB numbers. Unfortunately, the sine function is distorted by the rounding to integer RGB values that occurs in the VB6 program. The image is chosen to fill as much of the screen area as possible, and it has spatially uniform luminance and hue.
The form appearing on the monitor displays a command button for starting and stopping the image pulsing, together with scroll bars 52 and 53 respectively for adjustment of the pulse frequency F and the pulse amplitude A. These pulses could be initiated by a system timer which is activated upon the elapse of a preset time interval. However, timers in VB6 are too inaccurate for the purpose of providing the eight RGB adjustment points in each pulse cycle. An improvement can be obtained by using the GetTickCount function that is available in the Application Program Interface (API) of Windows 95(R) and Windows 98(R). The GetTickCount function returns the system time that has elapsed since starting Windows, expressed in milliseconds. User activation of the start button 54 provides a tick count TN through request 55 and sets the timer interval to TT miliseconds, in step 56. TT was previously calculated in the frequency routine that is activated by changing the frequency, denoted as step 52.
Since VB6 is an event-driven program, the flow chart for the program falls into disjoint pieces. Upon setting the timer interval to TT in step 56, the timer runs in the background while the program may execute subroutines such as adjustment of pulse frequency or amplitude. Upon elapse of the timer interval TT, the timer subroutine 57 starts execution with request 58 for a tick count, and in 59 an upgrade is computed of the time TN for the next point at which the RGB values are to be adjusted. In step 59 the timer is turned off, to be reactivated later in step 67. Step 59 also resets the parameter CR which plays a role in the extrapolation procedure 61 and the condition 60. For ease of understanding at this point, it is best to pretend that the action of 61 is simply to get a tick count, and to consider the loop controled by condition 60 while keeping CR equal to zero. The loop would terminate when the tick count M reaches or exceeds the time TN for the next phase point, at which time the program should adjust the image intensity through steps 63-65. For now step 62 is to be ignored also, since it has to do with the actual extrapolation procedure 61. The increments to the screen colors R1, G1, and B1 at the new phase point are computed according to the sine function, applied with the amplitude A that was set by the user in step 53. The number I that labels the phase point is incremented by unity in step 65, but if this results in I=8 the value is reset to zero in 66. Finally, the timer is reactivated in step 67, initiating a new ⅛-cycle step in the periodic progression of RGB adjustments.
A program written in this way would exhibit a large jitter in the times at which the RGB values are changed. This is due to the lumpiness in the tick counts returned by the GetTickCount function. The lumpiness may be studied separately by running a simple loop with C=GetTickCount, followed by writing the result C to a file. Inspection shows that C has jumped every 14 or 15 milliseconds, between long stretches of constant values. Since for a ½ Hz image intensity modulation the ⅛-cycle phase points are 250 ms apart, the lumpiness of 14 or 15 ms in the tick count would cause considerable inaccuracy. The full extrapolation procedure 61 is introduced in order to diminish the jitter to acceptable levels. The procedure works by refining the heavy-line staircase function shown in FIG. 8, using the slope RR of a recent staircase step to accurately determine the loop count 89 at which the loop controled by 60 needs to be exited. Details of the extrapolation procedure are shown in FIG. 7 and illustrated in FIG. 8. The procedure starts at 70 with both flags off, and CR=0, because of the assignment in 59 or 62 in FIG. 6. A tick count M is obtained at 71, and the remaining time MR to the next phase point is computed in 72. Conditions 77 and 73 are not satisfied and therefore passed vertically in the flow chart, so that only the delay block 74 and the assignments 75 are executed. Condition 60 of FIG. 6 is checked and found to be satisfied, so that the extrapolation procedure is reentered. The process is repeated until the condition 73 is met when the remaining time MR jumps down through the 15 ms level, shown in FIG. 8 as the transition 83. The condition 73 then directs the logic flow to the assignments 76, in which the number DM labeled by 83 is computed, and FLG1 is set. The computation of DM is required for finding the slope RR of the straight-line element 85. One also needs the “Final LM” 86, which is the number of loops traversed from step 83 to the next downward step 84, here shown to cross the MR=0 axis. The final LM is determined after repeatedly incrementing LM through the side loop entered from the FLG1=1 condition 77, which is now satisfied since FLG1 was set in step 76. At the transition 84 the condition 78 is met, so that the assignments 79 are executed. This includes computation of the slope RR of the line element 85, setting FLG2, and resetting FLG1. From here on, the extrapolation procedure increments CR in steps of RR while skipping tick counts until condition 60 of FIG. 6 is violated, the loop is exited, and the RGB values are adjusted.
A delay block 74 is used in order to stretch the time required for traversing the extrapolation procedure. The block can be any computation intensive subroutine such as repeated calculations of tangent and arc tangent functions.
As shown in step 56 of FIG. 6, the timer interval TT is set to 4/10 of the time TA from one RGB adjustment point to the next. Since the timer runs in the background, this arrangement provides an opportunity for execution of other processes such as user adjustment of frequency or amplitude of the pulses.
The adjustment of the frequency and other pulse parameters of the image intensity modulation can be made internally, i.e., within the running program. Such internal control is to be distinguished from the external control provided, for instance, in screen savers. In the latter, the frequency of animation can be modified by the user, but only after having exited the screen saver program. Specifically, in Windows 95(R) or Windows 98(R), to change the animation frequency requires stopping the screen saver execution by moving the mouse, whereafter the frequency may be adjusted through the control panel. The requirement that the control be internal sets the present program apart from so-called banners as well.
The program may be run on a remote computer that is linked to the user computer, as illustrated in FIG. 9. Although the monitor 2, labeled “MON”, is connected to the computer 31′, labeled “COMPUTER”, the program that pulses the images on the monitor 2 runs on the remoter computer 90, labeled “REMOTE COMPUTER”, which is connected to computer 31′ through a link 91 which may in part belong to a network. The network may comprise the Internet 92.
The monitor of a television set emits an electromagnetic field in much the same way as a computer monitor. Hence, a TV may be used to produce screen emissions for the purpose of nervous system manipulation. FIG. 5 shows such an arrangement, where the pulsing of the image intensity is achieved by inducing a small slowly pulsing shift in the frequency of the RF signal that enters from the antenna. This process is here called “frequency wobbling” of the RF signal. In FM TV, a slight slow frequency wobble of the RF signal produces a pseudo-dc signal level fluctuation in the composite video signal, which in turn causes a slight intensity fluctuation of the image displayed on the monitor in the same manner as discussed above for the modulator of FIG. 2. The frequency wobbling is induced by the wobbler 44 of FIG. 5 labeled “RFM”, which is placed in the antenna line 43. The wobbler is driven by the pulse generator 6, labeled “GEN”. The subject can adjust the frequency and the amplitude of the wobble through the tuning control 7 and the amplitude control 41. FIG. 10 shows a block diagram of the frequency wobbler circuit that employs a variable delay line 94, labelled “VDL”. The delay is determined by the signal from pulse generator 6, labelled “GEN”. The frequency of the pulses can be adjusted with the tuning control 7. The amplitude of the pulses is determined by the unit 98, labelled “MD”, and can be adjusted with the amplitude control 41. Optionally, the input to the delay line may be routed through a preprocessor 93, labelled “PRP”, which may comprise a selective RF amplifier and down converter; a complimentary up conversion should then be performed on the delay line output by a postprocessor 95, labelled “POP”. The output 97 is to be connected to the antenna terminal of the TV set.
The action of the variable delay line 94 may be understood as follows. Let periodic pulses with period L be presented at the input. For a fixed delay the pulses would emerge at the output with the same period L. Actually, the time delay T is varied slowly, so that it increases approximately by LdT/dt between the emergence of consecutive pulses at the device output. The pulse period is thus increased approximately by
ΔL=LdT/dt. (4)
In terms of the frequency ∫, Eq. (4) implies approximately
Δ∫/∫=−dT/dt. (5)
For sinusoidal delay T(t) with amplitude b and frequency g, one has
Δ∫/∫=−2πgb cos (2πgt), (6)
which shows the frequency wobbling. The approximation is good for gb<<1, which is satisfied in practice. The relative frequency shift amplitude 2πgb that is required for effective image intensity pulses is very small compared to unity. For a pulse frequency g of the order of 1 Hz, the delay may have to be of the order of a millisecond. To accomodate such long delay values, the delay line may have to be implemented as a digital device. To do so is well within the present art. In that case it is natural to also choose digital implementations for the pulse generator 6 and the pulse amplitude controller 98, either as hardware or as software.
Pulse variability may be introduced for alleviating the need for precise tuning to a resonance frequency. This may be important when sensory resonance frequencies are not precisely known, because of the variation among individuals, or in order to cope with the frequency drift that results from chemical detuning that is discussed in the '874 patent. A field with suitably chosen pulse variability can then be more effective than a fixed frequency field that is out of tune. One may also control tremors and seizures, by interfering with the pathological oscillatory activity of neural circuits that occurs in these disorders. Electromagnetic fields with a pulse variability that results in a narrow spectrum of frequencies around the frequency of the pathological oscillatory activity may then evoke nerve signals that cause phase shifts which diminish or quench the oscillatory activity.
Pulse variability can be introduced as hardware in the manner described in the '304 patent. The variability may also be introduced in the computer program of FIG. 6, by setting FLG3 in step 68, and choosing the amplitude B of the frequency fluctuation. In the variability routine 46, shown in some detail in FIG. 13, FLG3 is detected in step 47, whereupon in steps 48 and 49 the pulse frequency F is modified pseudo randomly by a term proportional to B, every 4th cycle. Optionally, the amplitude of the image intensity pulsing may be modified as well, in similar fashion. Alternatively, the frequency and amplitude may be swept through an adjustable ramp, or according to any suitable schedule, in a manner known to those skilled in the art. The pulse variability may be applied to subliminal image intensity pulses.
When an image is displayed by a TV monitor in response to a TV broadcast, intensity pulses of the image may simply be imbedded in the program material. If the source of video signal is a recording medium, the means for pulsing the image intensity may comprise an attribute of recorded data. The pulsing may be subliminal. For the case of a video signal from a VCR, the pertinent data attribute is illustrated in FIG. 11, which shows a video signal record on part of a video tape 28. Depicted schematically are segments of the video signal in intervals belonging to lines in three image frames at different places along the tape. In each segment, the chroma signal 9 is shown, with its short-term average level 29 represented as a dashed line. The short-term average signal level, also called the pseudo-dc level, represents the luminance of the image pixels. Over each segment, the level is here constant because the image is for simplicity chosen as having a uniform luminance over the screen. However, the level is seen to vary from frame to frame, illustrating a luminance that pulses slowly over time. This is shown in the lower portion of the drawing, wherein the IRE level of the short-term chroma signal average is plotted versus time. The graph further shows a gradual decrease of pulse amplitude in time, illustrating that luminance pulse amplitude variations may also be an attribute of the recorded data on the video tape. As discussed, pulsing the luminance for fixed chrominance results in pulsing of the image intensity.
Data stream attributes that represent image intensity pulses on video tape or in TV signals may be created when producing a video rendition or making a moving picture of a scene, simply by pulsing the illumination of the scene. This is illustrated in FIG. 12, which shows a scene 19 that is recorded with a video camera 18, labelled “VR”. The scene is illuminated with a lamp 20, labelled “LAMP”, energized by an electric current through a cable 36. The current is modulated in pulsing fashion by a modulator 30, labeled “MOD”, which is driven by a pulse generator 6, labelled “GENERATOR”, that produces voltage pulses 35. Again, pulsing the luminance but not the chrominance amounts to pulsing the image intensity.
The brightness of monitors can usually be adjusted by a control, which may be addressable through a brightness adjustment terminal. If the control is of the analog type, the displayed image intensity may be pulsed as shown in FIG. 15, simply by a pulse generator 6, labeled “GEN”, that is connected to the brigthness adjustment terminal 88 of the monitor 2, labeled “MON”. Equivalent action can be provided for digital brightness controls, in ways that are well known in the art.
The analog component video signal from a DVD player may be modulated such as to overlay image intensity pulses in the manner illustrated in FIG. 17. Shown are a DVD player 102, labeled “DVD”, with analog component video output comprised of the luminance Y and chrominance C. The overlay is accomplished simply by shifting the luminance with a voltage pulse from generator 6, labeled “GENERATOR”. The generator output is applied to modulator 106, labeled “SHIFTER”. Since the luminance Y is pulsed without changing the chrominance C, the image intensity is pulsed. The frequency and amplitude of the image intensity pulses can be adjusted respectively with the tuner 7 and amplitude control 107. The modulator 105 has the same structure as the modulator of FIG. 2, and the pulse amplitude control 107 operates the potentiometer 15 of FIG. 2. The same procedure can be followed for editing a DVD such as to overlay image intensity pulses, by processing the modulated luminance signal through an analog-to-digital converter, and recording the resulting digital stream onto a DVD, after appropriate compression. Alternatively, the digital luminance data can be edited by electronic reading of the signal, decompression, altering the digital data by software, and recording the resulting digital signal after proper compression, all in a manner that is well known in the art.
The mechanism whereby a CRT-type monitor emits a pulsed electromagnetic field when pulsing the intensity of an image is illustrated in FIG. 14. The image is produced by an electron beam 10 which impinges upon the backside 88 of the screen, where the collisions excite phosphors that subsequently emit light. In the process, the electron beam deposits electrons 18 on the screen, and these electrons contribute to an electric field 3 labelled “E”. The electrons flow along the conductive backside 88 of the screen to the terminal 99 which is hooked up to the high-voltage supply 40, labelled “HV”. The circuit is completed by the ground connection of the supply, the video amplifier 87, labeled “VA”, and its connection to the cathodes of the CRT. The electron beams of the three electron guns are collectively shown as 10, and together the beams carry a current J. The electric current J flowing through the described circuit induces a magnetic field 39, labeled “B”. Actually, there are a multitude of circuits along which the electron beam current is returned to the CRT cathodes, since on a macroscopic scale the conductive back surface 88 of the screen provides a continuum of paths from the beam impact point to the high-voltage terminal 99. The magnetic fields induced by the currents along these paths partially cancel each other, and the resulting field depends on the location of the pixel that is addressed. Since the beams sweep over the screen through a raster of horizontal lines, the spectrum of the induced magnetic field contains strong peaks at the horizontal and vertical frequencies. However, the interest here is not in fields at those frequencies, but rather in emissions that result from an image pulsing with the very low frequencies appropriate to sensory resonances. For this purpose a diffuse electron current model suffices, in which the pixel discreteness and the raster motion of the electron beams are ignored, so that the beam current becomes diffuse and fills the cone subtended by the displayed image. The resulting low-frequency magnetic field depends on the temporal changes in the intensity distribution over the displayed image. Order-of-magnitude estimates show that the low-frequency magnetic field, although quite small, may be sufficient for the excitation of sensory resonances in subjects located at a normal viewing distance from the monitor.
The monitor also emits a low-frequency electric field at the image pulsing frequency. This field is due in part to the electrons 18 that are deposited on the screen by the electron beams 10. In the diffuse electron beam model, screen conditions are considered functions of the time t and of the Cartesian coordinates x and y over a flat CRT screen.
The screen electrons 18 that are dumped onto the back of the screen by the sum j(x,y,t) of the diffuse current distributions in the red, green, and blue electron beams cause a potential distribution V(x,y,t) which is influenced by the surface conductivity σ on the back of the screen and by capacitances. In the simple model where the screen has a capacitance distribution c(x,y) to ground and mutual capacitances between parts of the screen at different potentials are neglected, a potential distribution V(x,y,t) over the screen implies a surface charge density distribution
q=Vc(x,y), (7)
and gives rise to a current density vector along the screen,
j s=−σgrads V, (8)
where grads is the gradient along the screen surface. Conservation of electric charge implies
j=c{dot over (V)}−div s (σgrad s V), (9)
where the dot over the voltage denotes the time derivative, and divs is the divergence in the screen surface. The partial differential equation (9) requires a boundary condition for the solution V(x,y,t) to be unique. Such a condition is provided by setting the potential at the rim of the screen equal to the fixed anode voltage. This is a good approximation, since the resistance Rr between the screen rim and the anode terminal is chosen small in CRT design, in order to keep the voltage loss JRr to a minimum, and also to limit low-frequency emissions.
Something useful can be learned from special cases with simple solutions. As such, consider a circular CRT screen of radius R with uniform conductivity, showered in the back by a diffuse electron beam with a spatially uniform beam current density that is a constant plus a sinusoidal part with frequency ∫. Since the problem is linear, the voltage V due to the sinusoidal part of the beam current can be considered separately, with the boundary condition that V vanish at the rim of the circular screen. Eq. (9) then simplifies to
V″+V″/r−i2π∫cn V=−Jη/A, r≦R, (10)
where r is a radial coordinate along the screen with its derivative denoted by a prime, η=1/σ is the screen resistivity, A the screen area, J the sinusoidal part of the total beam current, and i=(−1), the imaginary unit. Our interest is in very low pulse frequencies ∫ that are suitable for excitation of sensory resonances. For those frequencies and for practical ranges for c and η, the dimensionless number 2π∫cAη is very much smaller than unity, so that it can be neglected in Eq. (10). The boundary value problem then has the simple solution V ( r ) = J η 4 π ( 1 - ( r / R ) 2 ) . ( 11 )
Figure US06506148-20030114-M00001
In deriving (11) we neglected the mutual capacitance between parts of the screen that are at different potentials. The resulting error in (10) is negligible for the same reason that the i2π∫cAη term in (10) can be neglected.
The potential distribution V(r) of (11) along the screen is of course accompanied by electric charges. The field lines emanating from these charges run mainly to conductors behind the screen that belong to the CRT structure and that are either grounded or connected to circuitry with a low impedance path to ground. In either case the mentioned conductors must be considered grounded in the analysis of charges and fields that result from the pulsed component J of the total electron beam current. The described electric field lines end up in electric charges that may be called polarization charges since they are the result of the polarization of the conductors and circuitry by the screen emission. To estimate the pulsed electric field, a model is chosen where the mentioned conductors are represented together as a grounded perfectly conductive disc of radius R, positioned a short distance δ behind the screen, as depicted in FIG. 16. Since the grounded conductive disc carries polarization charges, it is called the polarization disc. FIG. 16 shows the circular CRT screen 88 and the polarization disc 101, briefly called “plates”. For small distances δ, the capacitance density between the plates of opposite polarity is nearly equal to ε/δ, where ε is the permittivity of free space. The charge distributions on the screen and polarization disc are respectively εV(r)/δ+q0 and −εV(r)/δ+q0, where the εV(r)/δ terms denote opposing charge densities at the end of the dense field lines that run between the two plates. That the part q0 is needed as well will become clear in the sequel.
The charge distributions εV(r)/δ+q0 and −εV(r)/δ+q0 on the two plates have a dipole moment with the density D ( r ) = εV ( r ) = J ηε 4 π ( 1 - ( r / R ) 2 ) , ( 12 )
Figure US06506148-20030114-M00002
directed perpendicular to the screen. Note that the plate separation δ has dropped out. This means that the precise location of the polarization charges is not critical in the present model, and further that δ may be taken as small as desired. Taking δ to zero, one thus arrives at the mathematical model of pulsed dipoles distributed over the circular CRT screen. The field due to the charge distribution q0 will be calculated later.
The electric field induced by the distributed dipoles (12) can be calculated easily for points on the centerline of the screen, with the result E ( z ) = V ( 0 ) R { 2 ρ / R - R / ρ - 2 z / R } , ( 13 )
Figure US06506148-20030114-M00003
where V(0) is the pulse voltage (11) at the screen center, ρ the distance to the rim of the screen, and z the distance to the center of the screen. Note that V(0) pulses harmonically with frequency ∫, because in (11) the sinusoidal part J of the beam current varies in this manner.
The electric field (13) due to the dipole distribution causes a potential distribution V(r)/2 over the screen and a potential distribution of −V(r)/2 over the polarization disc, where V(r) is nonuniform as given by (11). But since the polarization disc is a perfect conductor it cannot support voltage gradients, and therefore cannot have the potential distribution −V(r)/2. Instead, the polarization disc is at ground potential. This is where the charge distribution q0(r) comes in; it must be such as to induce a potential distribution V(r)/2 over the polarization disc. Since the distance between polarization disc and screen vanishes in the mathematical model, the potential distribution V(r)/2 is induced over the screen as well. The total potential over the monitor screen thus becomes V(r) of (11), while the total potential distribution over the polarization disc becomes uniformly zero. Both these potential distributions are as physically required. The electric charges q0 are moved into position by polarization and are partly drawn from the earth through the ground connection of the CRT.
In our model the charge distribution q0 is located at the same place as the dipole distribution, viz., on the plane z=0 within the circle with radius R. At points on the center line of the screen, the electric field due to the monopole distribution q0 is calculated in the following manner. As discussed, the monopoles must be such that they cause a potential φ0 that is equal to V(r)/2 over the disc with radius R centered in the plane z=0. Although the charge distribution q0(r) is uniquely defined by this condition, it cannot be calculated easily in a straightforward manner. The difficulty is circumvented by using an intermediate result derived from Excercise 2 on page 191 of Kellogg (1953), where the charge distribution over a thin disc with uniform potential is given. By using this result one readily finds the potential φ*(z) on the axis of this disc as φ * ( z ) = 2 π V * β ( R 1 ) , ( 14 )
Figure US06506148-20030114-M00004
where β(R1) is the angle subtended by the disc radius R1, as viewed from the point z on the disc axis, and V* is the disc potential. The result is used here in an attempt to construct the potential φ0(z) for a disc with the nonuniform potential V(r)/2, by the ansatz of writing the field as due to a linear combination of abstract discs with various radii R1 and potentials, all centered in the plane z=0. In the ansatz the potential on the symmetry axis is written φ 0 ( z ) = α β ( R ) + b ∫ 0 R β ( R 1 ) W , ( 15 )
Figure US06506148-20030114-M00005
where W is chosen as the function 1−R1 2/R2, and the constants a and b are to be determined such that the potential over the plane z=0 is V(r)/2 for radii r ranging from 0 to R, with V(r) given by (11). Carrying out the integration in (15) gives
φ0(z)=αβ(R)−b{(1+z 2 /R 2)β(R)−|z|/R}. (16)
In order to find the potential over the disc r<R in the plane z=0, the function φ0(z) is expanded in powers of z/R for 0<z<R, whereafter the powers zn are replaced by rnPn(cosθ), where the Pn are Legendre polynomials, and (r,θ) are symmetric spherical coordinates centered at the screen center. This procedure amounts to a continuation of the potential from the z-axis into the half ball r0, in such a manner that the Laplace equation is satisfied. The method is discussed by Morse and Feshbach (1953). The “Laplace continuation” allows calculation of the potential φ0 along the surface of the disc r0, the parts (13) and (19) contribute about equally to the electric field over a practical range of distances z. When going behind the monitor where z is negative the monopole field flips sign so that the two parts nearly cancel each other, and the resulting field is very small. Therefore, in the back of the CRT, errors due to imperfections in the theory are relatively large. Moreover our model, which pretends that the polarization charges are all located on the polarization disc, fails to account for the electric field flux that escapes from the outer regions of the back of the screen to the earth or whatever conductors happen to be present in the vincinity of the CRT. This flaw has relatively more serious consequences in the back than in front of the monitor.
Screen emissions in front of a CRT can be cut dramatically by using a grounded conductive transparent shield that is placed over the screen or applied as a coating. Along the lines of our model, the shield amounts to a polarization disc in front of the screen, so that the latter is now sandwiched between to grounded discs. The screen has the pulsed potential distribution V(r) of (11), but no electric flux can escape. The model may be modified by choosing the polarization disc in the back somewhat smaller than the screen disc, by a fraction that serves as a free parameter. The fraction may then be determined from a fit to measured fields, by minimizing the relative standard deviation between experiment and theory.
In each of the electron beams of a CRT, the beam current is a nonlinear function of the driving voltage, i.e., the voltage between cathode and control grid. Since this function is needed in the normalization procedure, it was measured for the 15″ computer monitor that has been used in the ½ Hz sensory resonance experiments and the electric field measurements. Although the beam current density j can be determined, it is easier to measure the luminance, by reading a light meter that is brought right up to the monitor screen. With the RGB values in the VB6 program taken as the same integer K, the luminance of a uniform image is proportional to the image intensity I. The luminance of a uniform image was measured for various values of K. The results were fitted with
I=c 1 K γ, (20)
where c1 is a constant. The best fit, with 6.18% relative standard deviation, was obtained for γ=2.32.
Screen emissions also occur for liquid crystal displays (LCD). The pulsed electric fields may have considerable amplitude for LCDs that have their driving electrodes on opposite sides of the liquid crystal cell, for passive matrix as well as for active matrix design, such as thin film technology (TFT). For arrangements with in-plane switching (IPS) however, the driving electrodes are positioned in a single plane, so that the screen emission is very small. For arrangements other than IPS, the electric field is closely approximated by the frin
My first quick (before going home from work) attempt at a transparent monitor picture. Colors are bad, the monitor background image is blurry and the monitor placement (or camera position) could be better. I'll make other attempts some other time.
Photos from a review of the LG 23ET83 touchscreen monitor. The full review can be found at: bit.ly/18MKo8T