Search This Blog

Sunday, June 10, 2018

Michio Kaku

From Wikipedia, the free encyclopedia
 
Michio Kaku
Michio Kaku Presentation.jpg
Kaku at Campus Party Brasil in 2012
Born January 24, 1947 (age 71)[1]
San Jose, California, United States
Residence New York City, United States
Nationality American
Alma mater Harvard University (B.Sc., 1968)
University of California, Berkeley (Ph.D., 1972)
Known for String field theory
Physics of the Impossible
Physics of the Future
The Future of the Mind
Spouse(s) Shizue Kaku
Children 2
Awards Klopsteg Memorial Award (2008)
Scientific career
Fields Theoretical physics
Institutions City University of New York
New York University
Institute for Advanced Study
Doctoral advisor Stanley Mandelstam
Website MKaku.org

Michio Kaku (/ˈmiːtʃioʊ ˈkɑːkuː/; born 24 January 1947) is an American theoretical physicist, futurist, and popularizer of science. He is a professor of theoretical physics in the City College of New York and CUNY Graduate Center. Kaku has written several books about physics and related topics, has made frequent appearances on radio, television, and film, and writes online blogs and articles. He has written three New York Times best sellers: Physics of the Impossible (2008), Physics of the Future (2011), and The Future of the Mind (2014). Kaku has hosted several TV specials for the BBC, the Discovery Channel, the History Channel, and the Science Channel.

Early life

Kaku was born in San Jose, California, to American Japanese parents.[2] His father, born in California and educated in both Japan and the United States, was fluent in Japanese and English. Both his parents were interned in the Tule Lake War Relocation Center during World War II, where they met and where his older brother was born.

While attending Cubberley High School in Palo Alto, Kaku assembled a particle accelerator in his parents' garage for a science fair project.[citation needed] His admitted goal was to generate "a beam of gamma rays powerful enough to create antimatter." At the National Science Fair in Albuquerque, New Mexico, he attracted the attention of physicist Edward Teller, who took Kaku as a protégé, awarding him the Hertz Engineering Scholarship. Kaku graduated summa cum laude from Harvard University in 1968 and was first in his physics class.[citation needed] He attended the Berkeley Radiation Laboratory at the University of California, Berkeley, and received a Ph.D. in 1972, and that same year held a lectureship at Princeton University.

Kaku was drafted into the United States Army during the Vietnam War. He completed his basic training at Fort Benning, Georgia, and advanced infantry training at Fort Lewis, Washington.[3] However, the Vietnam War ended before he was deployed as an infantryman.

Academic career

As part of the research program in 1975 and 1977 at the department of physics at The City College of The City University of New York, Kaku worked on research on quantum mechanics.[4][5] He was a Visitor and Member (1973 and 1990) at the Institute for Advanced Study in Princeton and New York University. He currently holds the Henry Semat Chair and Professorship in theoretical physics at the City College of New York.[6]

Kaku had a role in breaking the SSFL (Santa Susana Field Laboratory) story in 1979.[citation needed] The Santa Susana facility run by RocketDyne was responsible for an experimental sodium reactor which had an accident in Simi Valley in the 1950s. Kaku was a student involved in breaking the story of the leak of radiation.[citation needed]

Kaku has had more than 70 articles published in physics journals such as Physical Review, covering topics such as superstring theory, supergravity, supersymmetry, and hadronic physics.[7] In 1974, Kaku and Prof. Keiji Kikkawa of Osaka University co-authored the first papers describing string theory in a field form.[8]

Kaku is the author of several textbooks on string theory and quantum field theory.

Popular science

Kaku is most widely known as a popularizer of science[9] and physics outreach specialist. He has written books and appeared on many television programs as well as film. He also hosts a weekly radio program.

Books

Kaku is the author of various popular science books:
Hyperspace was a bestseller and voted one of the best science books of the year by The New York Times[9] and The Washington Post. Parallel Worlds was a finalist for the Samuel Johnson Prize for nonfiction in the UK.[10]

Radio

Kaku is the host of the weekly one-hour radio program Exploration, produced by the Pacifica Foundation's WBAI in New York. Exploration is syndicated to community and independent radio stations and makes previous broadcasts available on the program's website. Kaku defines the show as dealing with the general topics of science, war, peace and the environment.

In April 2006, Kaku began broadcasting Science Fantastic on 90 commercial radio stations in the United States. It is syndicated by Talk Radio Network and now[when?] reaches 130 radio stations and America's Talk on XM and remains the only nationally syndicated science radio program. Featured guests include Nobel laureates and top researchers in the fields of string theory, time travel, black holes, gene therapy, aging, space travel, artificial intelligence and SETI. When Kaku is busy filming for television, Science Fantastic goes on hiatus, sometimes for several months. Kaku is also a frequent guest on many programs, where he is outspoken in all areas and issues he considers of importance, such as the program Coast to Coast AM where, on 30 November 2007, he reaffirmed his belief that the existence of extraterrestrial life is a certainty.[11] During the debut of Art Bell's new radio show Dark Matter on September 16, 2013, Bell referred to Kaku as "the next Carl Sagan", referring to Kaku's similar ability to explain complex science so anyone can understand it.

Kaku has appeared on many mainstream talk shows, discussing popular fiction such as Back to the Future, Lost, and the theories behind the time travel these and other fictional entertainment focus on.

Television and film

Kaku has appeared in many forms of media and on many programs and networks, including Good Morning America, The Screen Savers, Larry King Live, 60 Minutes, Imus In The Morning, Nightline, 20/20, Naked Science, CNN, ABC News, CBS News, NBC News, Al Jazeera English, Fox News Channel, The History Channel, Conan, The Science Channel, The Discovery Channel, TLC, Countdown with Keith Olbermann, The Colbert Report, The Art Bell Show and its successor, Coast to Coast AM, BBC World News America, The Covino & Rich Show, Head Rush, Late Show with David Letterman, and Real Time with Bill Maher. He was interviewed for two PBS documentaries, The Path to Nuclear Fission: The Story of Lise Meitner and Otto Hahn and Out from the Shadows: The Story of Irène Joliot-Curie and Frédéric Joliot-Curie, which were produced and directed by his former WBAI radio colleague Rosemarie Reed.[12]

In 1999, Kaku was one of the scientists profiled in the feature-length film Me & Isaac Newton, directed by Michael Apted. It played theatrically in the United States, was later broadcast on national TV, and won several film awards.[citation needed]

In 2005, Kaku appeared in the short documentary film Obsessed & Scientific about the possibility of time travel and the people who dream about it. It screened at the Montreal World Film Festival; a feature film expansion is in development talks. Kaku also appeared in the ABC documentary UFOs: Seeing Is Believing, in which he suggested that while he believes it is extremely unlikely that extraterrestrials have ever actually visited Earth, we must keep our minds open to the possible existence of civilizations a million years ahead of us in technology, where entirely new avenues of physics open up. He also discussed the future of interstellar exploration and alien life in the Discovery Channel special Alien Planet as one of the multiple speakers who co-hosted the show, and Einstein's Theory of Relativity on The History Channel.[citation needed]

In February 2006, Kaku appeared as presenter in the BBC-TV four-part documentary Time which seeks to explore the mysterious nature of time. Part one of the series concerns personal time, and how we perceive and measure the passing of time. The second in the series deals with cheating time, exploring possibilities of extending the lifespan of organisms. The geological time covered in part three explores the ages of the Earth and the Sun. Part four covers the topics of cosmological time, the beginning of time and the events that occurred at the instant of the big bang.

On January 28, 2007, Kaku hosted the Discovery Channel series 2057. This three-hour program discussed how medicine, the city, and energy could change over the next 50 years.

In 2008, Kaku hosted the three-hour BBC-TV documentary Visions of the Future, on the future of computers, medicine, and quantum physics, and he appeared in several episodes of the History Channel's Universe series.

On December 1, 2009, he began hosting a 12-episode weekly TV series for the Science Channel at 10 pm, called Sci Fi Science: Physics of the Impossible, based on his best-selling book. Each 30-minute episode discusses the scientific basis behind imaginative schemes, such as time travel, parallel universes, warp drive, star ships, light sabers, force fields, teleportation, invisibility, death stars, and even superpowers and flying saucers. Each episode includes interviews with the world's top scientists working on prototypes of these technologies, interviews with science fiction fans, clips from science fiction movies, and special effects and computer graphics. Although these inventions are impossible today, the series discusses when these technologies might become feasible in the future.

In 2010, he began to appear in a series on the website Gametrailers.com called Science of Games, discussing the scientific aspects of various popular video games such as Mass Effect 2 and Star Wars: The Force Unleashed.

Kaku is popular in mainstream media because of his knowledge and his accessible approach to presenting complex subjects in science. While his technical writings are confined to theoretical physics, his public speaking and media appearances cover a broad range of topics, from the Kardashev scale to more esoteric subjects such as wormholes and time travel. In January 2007, Kaku visited Oman. While there, he talked at length to select members of that country's decision makers. In an interview with local media, Kaku elaborated on his vision of mankind's future. Kaku considers climate change and terrorism as serious threats in man's evolution from a Type 0 civilization to Type 1 on the Kardashev scale.[13]

He is featured in Symphony of Science's songs, "The Quantum World", "Our Place in the Cosmos", "The Secret of the Stars", and "Monsters of the Cosmos"

On October 11, 2010, Michio Kaku appeared in the BBC program "What Happened Before the Big Bang" (along with Laura Mersini-Houghton, Andrei Linde, Roger Penrose, Lee Smolin, Neil Turok, and other notable cosmologists and physicists), where he propounded his theory of the universe created out of nothing.[14]

Over 22–25 January 2011, Kaku was invited to the fifth annual Global Competitiveness Forum (GCF), held in Riyadh, Saudi Arabia, next to renowned specialists including the British journalist Nick Pope, the Canadian ufologist Stanton Friedman, and the French astrophysicist Jacques Vallée.[15]

Kaku appears on the DVD and Blu-ray extras of the 2012 version of Total Recall, discussing the technological aspects of the future explored in the film.

Web Series

In 2018, Kaku hosts the web series Next World with Michio Kaku on CuriosityStream.

Policy advocacy and activism

Kaku has publicly stated his concerns over matters including people denying the anthropogenic cause of global warming, nuclear armament, nuclear power and what he believes to be the general misuse of science.[16] He was critical of the Cassini–Huygens space probe because of the 72 pounds (33 kg) of plutonium contained in the craft for use by its radioisotope thermoelectric generator. Conscious of the possibility of casualties if the probe's fuel were dispersed into the environment during a malfunction and crash as the probe was making a 'sling-shot' maneuver around Earth, Kaku publicly criticized NASA's risk assessment.[17] He has yet to comment on the successful mission.

His remark from an interview in support of SETI, "We could be in the middle of an intergalactic conversation... and we wouldn't even know", is used in the third Symphony of Science installment "Our Place in the Cosmos". Michio Kaku is also a member of the CuriosityStream Advisory Board.[18]

Personal life

Kaku is married to Shizue Kaku and has two daughters, Alyson and Michelle.[19][20]

In popular culture

In 2016, Kaku appeared in a TV commercial for TurboTax.[21]

Works

Filmography

at

Neurostimulation

From Wikipedia, the free encyclopedia
 
Neurostimulation
OPS-301 code 8-631

Neurostimulation is the purposeful modulation of the nervous system's activity using invasive (e.g. microelectrodes) or non-invasive means (e.g. transcranial magnetic stimulation or transcranial electric stimulation, tES, such as tDCS or transcranial alternating current stimulation, tACS). Neurostimulation usually refers to the electromagnetic approaches to neuromodulation.

Neurostimulation technology can improve the life quality of those who are severely paralyzed or suffering from profound losses to various sense organs, as well as for permanent reduction of severe, chronic pain which would otherwise require constant (around-the-clock), high-dose opioid therapy (such as neuropathic pain and spinal-cord injury). It serves as the key part of neural prosthetics for hearing aids, artificial vision, artificial limbs, and brain-machine interfaces. In the case of neural stimulation, mostly an electrical stimulation is utilized and charge-balanced biphasic constant current waveforms or capacitively coupled charge injection approaches are adopted. Alternatively, transcranial magnetic stimulation and transcranial electric stimulation have been proposed as non-invasive methods in which either a magnetic field or transcranially applied electric currents cause neurostimulation.[1][2]

Brain stimulation

Brain stimulation has potentials to treat some disorders such as epilepsy. In this method, scheduled stimulation is applied to specific cortical or subcortical targets. There are available commercial devices[3] that can deliver an electrical pulse at scheduled time intervals. Scheduled stimulation is hypothesized to alter the intrinsic neurophysiologic properties of epileptic networks. The most explored targets for scheduled stimulation are the anterior nucleus of the thalamus and the hippocampus. The anterior nucleus of the thalamus has been studied, which has shown a significant seizure reduction with the stimulator on versus off during several months after stimulator implantation.[4] Moreover, the cluster headache (CH) can be treated by using a temporary stimulating electrode at sphenopalatine ganglion (SPG). Pain relief is reported within several minutes of stimulation in this method.[5] To avoid use of implanted electrodes, researchers have engineered ways to inscribe a "window" made of zirconia that has been modified to be transparent and implanted in mice skulls, to allow optical waves to penetrate more deeply, as in optogenetics, to stimulate or inhibit individual neurons.[6]

Deep brain stimulation

Deep brain stimulation (DBS) has shown benefits for movement disorders such as Parkinson's disease, tremor and dystonia and affective disorders such as depression, obsessive-compulsive disorder, Tourette syndrome, chronic pain and cluster headache. Since DBS can directly change the brain activity in a controlled manner, it is used to map fundamental mechanisms of brain functions along with neuroimaging methods. A simple DBS system consists of two different parts. First, tiny microelectrodes are implanted in the brain to deliver stimulation pulses to the tissue. Second, an electrical pulse generator (PG) generates stimulation pulses, which is connected to the electrodes via microwires. Physiological properties of the brain tissue, which may change with disease state, stimulation parameters, which include amplitude and temporal characteristics, and the geometric configuration of the electrode and the surrounding tissue are all parameters on which DBS of both the normal and the diseased brain depend on. In spite of a huge amount of studies on DBS, its mechanism of action is still not well understood. Developing DBS microelectrodes is still challenging.[7]

Non-invasive brain stimulation

rTMS in a rodent. From Oscar Arias-Carrión, 2008

Transcranial magnetic stimulation

Compared to electrical stimulation that utilizes brief, high-voltage electric shock to activate neurons, which can potentially activate pain fibers, transcranial magnetic stimulation (TMS) was developed by Baker in 1985. TMS uses a magnetic wire above the scalp, which carries a sharp and high current pulse. A time variant magnetic field is induced perpendicular to the coil due to the applied pulse which consequently generates an electric field based on Maxwell's law. The electric field provides the necessary current for a non-invasive and much less painful stimulation. There are two TMS devices called single pulse TMS and repetitive pulse TMS (rTMS) while the latter has greater effect but potential to cause seizure. TMS can be used for therapy particularly in psychiatry, as a tool to measure central motor conduction and a research tool to study different aspects of human brain physiology such as motor function, vision, and language. The rTMS method has been used to treat epilepsy with rates of 8–25 Hz for 10 seconds. The other therapeutic uses of rTMS include parkinson diseases, dystonia and mood diseases. Also, TMS can be used to determine the contribution of cortical networks to specific cognitive functions by disrupting activity in the focal brain region.[1] Early, inconclusive, results have been obtained in recovery from coma (persistent vegetative state) by Pape et al. (2009).[8]
 
Transcranial electrical stimulation techniques. While tDCS uses constant current intensity, tRNS and tACS use oscillating current. The vertical axis represents the current intensity in milliamp (mA), while the horizontal axis illustrates the time-course.

Transcranial electrical stimulation

Spinal cord stimulation

Spinal cord stimulation (SCS) is an effective therapy for the treatment of chronic and intractable pain including diabetic neuropathy, failed back surgery syndrome, complex regional pain syndrome, phantom limb pain, ischemic limb pain, refractory unilateral limb pain syndrome, postherpetic neuralgia and acute herpes zoster pain. Another pain condition that is a potential candidate for SCS treatment is Charcot-Marie-Tooth (CMT) disease, which is associated with moderate to severe chronic extremity pain.[9] SCS therapy consists of the electrical stimulation of the spinal cord to 'mask' pain. The gate theory proposed in 1965 by Melzack and Wall[10] provided a theoretical construct to attempt SCS as a clinical treatment for chronic pain. This theory postulates that activation of large diameter, myelinated primary afferent fibers suppresses the response of dorsal horn neurons to input from small, unmyelinated primary afferents. A simple SCS system consists of three different parts. First, microelectrodes are implanted in the epidural space to deliver stimulation pulses to the tissue. Second, an electrical pulse generator implanted in the lower abdominal area or gluteal region while is connected to the electrodes via wires, and third a remote control to adjust the stimulus parameters such as pulse width and pulse rate in the PG. Improvements have been made in both the clinical aspects of SCS such as transition from subdural placement of contacts to epidural placement, which reduces the risk and morbidity of SCS implantation, and also technical aspects of SCS such as improving percutaneous leads, and fully implantable multi-channel stimulators. However, there are many parameters that need to be optimized including number of implanted contacts, contact size and spacing, and electrical sources for stimulation. The stimulus pulse width and pulse rate are important parameters that need to be adjusted in SCS, which are typically 400 us and 8–200 Hz respectively.[11]

Transcutaneous supraorbital nerve stimulation

Tentative evidence supports transcutaneous supraorbital nerve stimulation.[12] Side effects are few.[13]

Cochlear implants

Cochlear implant

Cochlear implants have provided partial hearing to more than 120,000 persons worldwide as of 2008. The electrical stimulation is used in a cochlear implant to provide functional hearing in totally deafened persons. Cochlear implants include several subsystem components from the external speech processor and radio frequency (RF) transmission link to the internal receiver, stimulator, and electrode arrays. Modern cochlear implant research started in the 1960s and 1970s. In 1961, a crude single electrode device was implanted in two deaf patients and useful hearing with electric stimulation was reported. The first FDA approved complete single channel device was released in 1984.[14] In cochlear implants, the sound is picked up by a microphone and transmitted to the behind-the-ear external processor to be converted to the digital data. The digitized data is then modulated on a radio frequency signal and transmitted to an antenna inside a headpiece. The data and power carrier are transmitted through a pair of coupled coils to the hermetically sealed internal unit. By extracting the power and demodulating the data, electric current commands are sent to the cochlea to stimulate the auditory nerve through microelectrodes.[15] The key point is that the internal unit does not have a battery and it should be able to extract the required energy. Also to reduce the infection, data is transmitted wirelessly along with power. Inductively coupled coils are the best candidate for power and data telemetry. Parameters needed by the internal unit include the pulse amplitude, pulse duration, pulse gap, active electrode, and return electrode that are used to define a biphasic pulse and the stimulation mode. An example of the commercial devices include Nucleus 22 device that utilized a carrier frequency of 2.5 MHz and later in the newer revision called Nucleus 24 device, the carrier frequency was increased to 5 MHz.[16] The internal unit in the cochlear implants is an ASIC (application-specific integrated circuit) chip that is responsible to ensure safe and reliable electric stimulation. Inside the ASIC chip, there is a forward pathway, a backward pathway, and control units. The forward pathway recovers digital information from the RF signal which includes stimulation parameters and some handshaking bits to reduce the communication error. The backward pathway usually includes a back telemetry voltage sampler that reads the voltage over a period of time on the recording electrode. The stimulator block is responsible to deliver predetermined current by external unit to the microelectrodes. This block includes a reference current and a digital to analog converter to transform digital commands to an analog current.[17]

Visual prosthesis

Visual cortical implant designed by Mohamad Sawan
The Visual Cortical Implant

Theoretical and experimental clinical evidences suggest that direct electrical stimulation of the retina might be able to provide some vision to subjects who have lost the photoreceptive elements of their retina.[18] Therefore, visual prostheses are developed to restore vision for the blind by using the stimulation. Depending upon which visual pathway location is targeted for neural stimulation, different approaches have been considered. Visual pathway consists mainly of the eye, optic nerve, lateral geniculate nucleus (LGN), and visual cortex. Therefore, retinal, optic nerve and visual cortex stimulation are the three different methods used in visual prostheses.[19] Retinal degenerative diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD), are two likely candidate diseases in which retinal stimulation may be helpful. Three approaches called intraocular epiretinal, subretinal and extraocular transretinal stimulation are pursued in retinal devices that stimulate remaining retinal neural cells to bypass lost photoreceptors and allow the visual signal to reach the brain via the normal visual pathway. In epiretinal approach, electrodes are placed on the top side of the retina near ganglion cells,[20] whereas the electrodes are placed under the retina in subretinal approaches.[21] Finally, the posterior scleral surface of the eye is the place in which extraocular approach electrodes are positioned. Second Sight and the Humayun group at USC are the most active groups in the design of intraocular retinal prostheses. The ArgusTM 16 retinal implant is an intraocular retinal prosthesis utilizing video processing technologies. Regarding to the visual cortex stimulation, Brindley, and Dobelle were the first ones who did the experiments and demonstrated that by stimulating the top side of the visual cortex most of the electrodes can produce visual percept.[11] More recently Sawan built a complete implant for intracortical stimulation and validated the operation in rats[22]

A pacemaker, scale in centimeters

LGN, which is located in the midbrain to relay signals from the retina to the visual cortex, is another potential area that can be used for stimulation. But this area has limited access due to surgical difficulty. The recent success of deep brain stimulation techniques targeting the midbrain has encouraged research to pursue the approach of LGN stimulation for a visual prosthesis.[23]

Cardiac electrostimulation devices

Implantable pacemakers were proposed for the first time in 1959 and became more sophisticated since then. The therapeutic application of pacemakers consists of numerous rhythm disturbances including some forms of tachycardia (too fast a heart beat), heart failure, and even stroke. Early implantable pacemakers worked only a short time and needed periodic recharging by an inductive link. These implantable pacemakers needed a pulse generator to stimulate heart muscles with a certain rate in addition to electrodes.[24] Today, modern pulse generators are programmed non-invasively by sophisticated computerized machines using RF, obtaining information about the patient's and device's status by telemetry. Also they use a single hermetically sealed lithium iodide (LiI) cell as the battery. The pacemaker circuitry includes sense amplifiers to detect the heart's intrinsic electrical signals, which are used to track heart activity, rate adaptive circuitry, which determine the need for increased or reduced pacing rate, a microprocessor, memory to store the parameters, telemetry control for communication protocol and power supplies to provide regulated voltage.[25]

Stimulation microelectrode technologies

Utah microelectrode array

Microelectrodes are one of the key components of the neurostimulation, which deliver the current to neurons. Typical microelectrodes have three main components: a substrate (the carrier), a conductive metal layer, and an insulation material. In cochlear implants, microelectrodes are formed from platinum-iridium alloy. State-of-the-art electrodes include deeper insertion to better match the tonotopic place of stimulation to the frequency band assigned to each electrode channel, improving efficiency of stimulation, and reducing insertion related trauma. These cochlear implant electrodes are either straight or spiral such as Med El Combi 40+ and Advanced Bionics Helix microelectrodes respectively. In visual implants, there are two types of electrode arrays called planar type or three dimensional needle or pillar type, where needle type array such as Utah array is mostly used for cortical and optic nerve stimulations and rarely used in retinal implants due to the possible damage of retina. However, a pillar-shaped gold electrode array on thin-film polyimide has been used in an extraocular implant. On the other hand, planar electrode arrays are formed from flexible polymers, such as silicone, polyimide, and parylene as candidates for retinal implants. Regarding to DBS microelectrodes an array, which can be controlled independently, distributed throughout the target nucleus would permit precise control of the spatial distribution of the stimulation, and thus, allow better personalized DBS. There are several requirements for DBS microelectrodes that include long lifetime without injury to the tissue or degradation of the electrodes, customized for different brain sites, long-term biocompatibility of the material, mechanically durable in order to reach the target without being damaged during handling by the implant surgeon, and finally uniformity of performance across the microelectrodes in a particular array. Tungsten microwire, iridium microwires, and sputtered or electrodeposited[26] Platinum-iridium alloy microelectrodes are the examples of microelectrode used in DBS.[11] Silicon carbide is a potential interesting material for realizing biocompatible semiconductor devices.[27]

History

The primary findings about neurostimulation originated from the idea to stimulate nerves for therapeutic purposes. The 1st recorded use of electrical stimulation for pain relief goes back to 46 AD, when Scribonius Largus used torpedo fish (electric ray) for relieving headaches.[28] In the late 18th century, Luigi Galvani discovered that the muscles of dead frog legs twitched when struck by direct current on the nervous system.[29] The modulation of the brain activity by electrical stimulation of the motor cortex in dogs was shown in 1870 that resulted in limb movement.[30] From the late 18th century to today many milestones have been developed. Nowadays, sensory prosthetic devices, such as visual implants, cochlear implants, auditory midbrain implants, and spinal cord stimulators and also motor prosthetic devices, such as deep brain stimulators, Bion microstimulators, the brain control and sensing interface, and cardiac electro-stimulation devices are widely used.[11]

In 2013 the British pharmaceutical company GlaxoSmithKline (GSK) coined the term "electroceutical" to broadly encompass medical devices that use electrical, mechanical, or light stimulation to affect electrical signaling in relevant tissue types.[31][32] Clinical neural implants such as cochlear implants to restore hearing, retinal implants to restore sight, spinal cord stimulators for pain relief or cardiac pacemakers and implantable defibrillators are proposed examples of electroceuticals.[31] GSK formed a venture fund and said it would host a conference in 2013 to lay out a research agenda for the field.[33] A 2016 review of research on interactions between the nervous and immune systems in autoimmune disorders and mentioned "electroceuticals" in passing and quotation marks, referring to neurostimulation devices in development for conditions like arthritis.[34]

Research

In addition to the enormous usage of neurostimulation for clinical applications, it is also used widely in laboratories started dates back to 1920s by people link Delgado who used stimulation as an experimental manipulation to study basics of how the brain works. The primary works were on the reward center of the brain in which stimulation of those structures led to pleasure that requested more stimulation. Another most recent example is the electrical stimulation of the MT area of primary visual cortex to bias perception. In particular, the directionality of motion is represented in a regular way in the MT area. They presented monkeys with moving images on screen and monkey throughput was to determine what the direction is. They found that by systematically introducing some errors to the monkey's responses, by stimulating the MT area which is responsible for perceiving the motion in another direction, the monkey responded to somewhere in between the actual motion and the stimulated one. This was an elegant use of stimulation to show that MT area is essential in the actual perception of motion. Within the memory field, stimulation is used very frequently to test the strength of the connection between one bundle of cells to another by applying a small current in one cell which results in the release of neurotransmitters and measuring the postsynaptic potential.

Generally, a short but high-frequency current in the range of 100 Hz helps strengthening the connection known as long-term potentiation. However, longer but low-frequency current tends to weaken the connections known as long-term depression.[35]
at

Paul Davies

From Wikipedia, the free encyclopedia

Paul Davies
Paul Davies 2016.jpg
Davies in 2016
Born Paul Charles William Davies
22 April 1946 (age 72)
London, England
Nationality British
Alma mater University College London
Known for Fulling–Davies–Unruh effect
Bunch–Davies vacuum state
Awards Templeton Prize (1995)
Kelvin Medal (2001)
Faraday Prize (2002)
Klumpke-Roberts Award (2011)
Scientific career
Fields Physicist
Institutions Arizona State University
University of Cambridge
University of Adelaide
Macquarie University
University of Newcastle
Thesis Contributions to theoretical physics: (i) Radiation damping in the optical continuum; (ii) A quantum theory of Wheeler–Feynman electrodynamics (1970)
Doctoral advisor Michael J. Seaton[1]
Sigurd Zienau
Other academic advisors Fred Hoyle (postdoc advisor)
Website http://cosmos.asu.edu/

Paul Charles William Davies, AM (born 22 April 1946) is an English physicist, writer and broadcaster, a professor at Arizona State University as well as the Director of BEYOND: Center for Fundamental Concepts in Science. He is affiliated with the Institute for Quantum Studies at Chapman University in California. He has held previous academic appointments at the University of Cambridge, University College London, University of Newcastle upon Tyne, University of Adelaide and Macquarie University. His research interests are in the fields of cosmology, quantum field theory, and astrobiology. He has proposed that a one-way trip to Mars could be a viable option.

In 2005, he took up the chair of the SETI: Post-Detection Science and Technology Taskgroup of the International Academy of Astronautics. He is also an adviser to the Microbes Mind Forum.

Education

Davies was brought up in Finchley, London. He attended Woodhouse Grammar School and then studied physics at University College London, gaining a first class Bachelor of Science degree in 1967.

In 1970, he completed his PhD under the supervision of Michael J. Seaton and Sigurd Zienau at University College London.[1][2] He then carried out postdoctoral research under Fred Hoyle at the University of Cambridge.

Scientific research

Davies' inquiries have included theoretical physics, cosmology, and astrobiology; his research has been mainly in the area of quantum field theory in curved spacetime. His notable contributions are the so-called Fulling–Davies–Unruh effect, according to which an observer accelerating through empty space will be subject to a bath of induced thermal radiation, and the Bunch–Davies vacuum state, often used as the basis for explaining the fluctuations in the cosmic background radiation left over from the big bang. A paper co-authored with Stephen Fulling and William Unruh was the first to suggest that black holes evaporating via the Hawking effect lose mass as a result of a flux of negative energy streaming into the hole from the surrounding space. Davies has had a longstanding association with the problem of time's arrow, and was also an early proponent of the theory that life on Earth may have come from Mars cocooned in rocks ejected by asteroid and comet impacts. During his time in Australia he helped establish the Australian Centre for Astrobiology.

Davies was a co-author of Felisa Wolfe-Simon on the Science article "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus".[3] Reports refuting the most significant aspects of the original results were published in the same journal in 2012, including by researchers from the University of British Columbia and Princeton University.[4]

Davies is Principal Investigator at Arizona State University's Center for Convergence of Physical Science and Cancer Biology. This is part of a program set up by the National Institutes of Health's National Cancer Institute to involve physicists in cancer research which has set up a network of 12 Physical Sciences-Oncology Centers.[5][6][7]

Awards

Davies' talent as a communicator of science has been recognized in Australia by an Advance Australia Award and two Eureka Prizes, and in the UK by the 2001 Kelvin Medal and Prize by the Institute of Physics, and the 2002 Faraday Prize by The Royal Society. Davies received the Templeton Prize in 1995.

Davies was made a member of the Order of Australia in the 2007 Queen's birthday honours list.

The asteroid 6870 Pauldavies is named after him.

Media work

Davies writes and comments on scientific and philosophical issues. He made a documentary series for BBC Radio 3, and two Australian television series, The Big Questions and More Big Questions. His BBC documentary The Cradle of Life featured the subject of his Faraday Prize lecture. He writes regularly for newspapers and magazines worldwide. He has been guest on numerous radio and television programmes including the children's podcast programme Ask A Biologist.

A 2007 opinion piece "Taking Science on Faith" in the New York Times,[8] generated controversy over its exploration of the role of faith in scientific inquiry. Davies argued that the faith scientists have in the immutability of physical laws has origins in Christian theology, and that the claim that science is "free of faith" is "manifestly bogus."[8] The Edge Foundation presented a criticism of Davies' article written by Jerry Coyne, Nathan Myhrvold, Lawrence Krauss, Scott Atran, Sean Carroll, Jeremy Bernstein, PZ Myers, Lee Smolin, John Horgan, Alan Sokal and a response by Davies beginning I was dismayed at how many of my detractors completely misunderstood what I had written. Indeed, their responses bore the hallmarks of a superficial knee-jerk reaction to the sight of the words "science" and "faith" juxtaposed.[9] While atheists Richard Dawkins[10] and Victor J. Stenger[11] have criticised Davies' public stance on science and religion, others, including the John Templeton Foundation, have praised his work.

Davies wrote an article in the Wall Street Journal describing the background to the December 2010 arsenic bacteria press conference and stating that he supported the finding of Felisa Wolfe-Simon that arsenic can replace phosphorus because "I had the advantage of being unencumbered by knowledge. I dropped chemistry at the age of 16, and all I knew about arsenic came from Agatha Christie novels."[12] He also made the statement, "Well, I would be astonished if this was the only arsenic-based organism on Earth and Felisa just happened to scrape it up from the bottom of Mono Lake on the first try, It's quite clear that it is the tip of an iceberg. I think it's a window into a whole new world of microbiology. And as a matter of fact, she already has 20 or so candidate other organisms that we're very anxious to take a look at. I think we're going to see a whole new domain of life here." [13] It was later independently demonstrated that the organism's DNA contained no arsenic at all.[14][15][16][17] In a similar vein, a 2013 article in The Guardian by Davies suggested that the origin of life will be uncovered through information theory rather than chemistry.[18] Concerns have been raised about his responsibility as one of Wolfe-Simon's co-authors.[19]

In popular culture

  • The novel Naive, Super, by Norwegian writer Erlend Loe (translated by Tor Ketil Solberg), published in 1996, refers to Davies frequently.
  • Numbers (season 5, episode 12) refers to Paul Davies' Cosmic Think Tank at Arizona State.
  • Lawrence Leung's Unbelievable (season 1, episode 3), Leung interviews Paul Davies on Alien abduction, where Paul admits to having experienced sleep paralysis.
  • The novel The Extinction Machine, by American writer Jonathan Maberry, published in 2013, refers to Paul Davies.
  • Paul Davies' book "How to Build a Time Machine" was the primary influence on the song Time Machine Fix by the independent rock band Blue Eyed Infidels. Davies is mentioned by name in the song as someone to consult about fixing the past using the knowledge of time travel.

Works

Popular books

Technical books

  • 1974 The Physics of Time Asymmetry, University of California Press, Berkeley California,
  • 1982 (with N. D. Birrell) Quantum Fields in Curved Space, Series: Cambridge Monographs on Mathematical Physics, Cambridge University Press.[20]
  • 1984 Quantum Mechanics, (with David S. Betts), 2nd edition, CRC Press, 1994.

Essays and papers

at
Subscribe to: Posts (Atom)

Introduction to entropy

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Introduct...

  • Islamic State and the Levant
    From Wikipedia, the free encyclopedia Islamic State of Iraq and the Levant الدولة الإسلامية في العراق والشام   ( ...
  • Heart Sutra
    From Wikipedia, the free encyclopedia A reproduction of the palm -leaf manuscript in Siddham script ...
  • Slum
    From Wikipedia, the free encyclopedia ...