text stringlengths 378 651k | id stringlengths 47 47 | metadata dict |
|---|---|---|
The Sieve of Eratosthenes
To generate all prime numbers, i.e. primes, in a given range, the sieve of Eratosthenes is an old,
but nevertheless still the most efficiently known algorithm. It works as follows:
Put into an array all natural numbers up to a given limit size. Set
the first sieve prime = 2. Then cross out all multiples of the current sieve prime. Next,
look for the next larger, not crossed-out number. It will become the new sieve
prime. Repeat this process with the next not crossed out number until all
numbers are worked off. Here this process is illustrated for the odd numbers < 360:
Obviously, crossing out of multiples need to start firstly at the square
of the new chosen sieve prime. So the total effort is about size SUMp
1/p where the sum is taken over all primes less than sqrt(size).
The sum can be estimated rather well to be about ln(ln(size)/2)+0.261497. Hence, for large sieve sizes, the time of the algorithm should be roughly
proportional to the sieve size, because the function ln(ln(x)) increases so slowly.
After seen some "fast" implementations of this algorithm by other people,
I decided to
write my own, really fast and less memory consuming computer program.
There are four main improvement points for
The Art of Prime Sieving
With these tricks in mind (and a lot of optimization), I wrote a C-program
which was the fastest sieve-of-Eratosthenes implementation, I ever became aware of. In May 1998, I have further refined the algorithm with an even denser sieve, resulting in access to fixed bit-positions, and a quicker presieving. These improvements gain at least 15% speed-up over the old version.
To give you a feeling of its speed: it generates all primes
less than 1 milliard in less than 1 minute and all primes up to 2^32 in less
than 3.5 minutes on a 133 MHz Pentium CPU (I used sieve size = 8000 Bytes (processor has 8 KB Data-Cache), smallest primes = 2,3,5 and gcc-2.7.2!).
- Dense bit packing for the crossing-out flags
- To use the memory efficiently, it is necessary to mark the numbers not in
a byte or even a word of the computer, but in a bit only. This must be done
very clever, because bit-access is much more expensive in cpu-time than
byte-access or the CPU-prefered word-access!
- Only presieved numbers in the sieve
- With exception of 2, all other primes are odd, so we need only to store the flags for
the odd numbers in the sieve. But furthermore, only the numbers 6k+1
and 6k+5 can be primes (except 2 and 3). So, we can reduce the total amount
of sieve memory by a factor of 3 storing only the flags for these numbers. If we even exclude all multiples of 5, resulting in a factor of 3.75, we need only 8 flags each 30 numbers. This is
really nice, because 1 byte has 8 bits!
- Don't bother with multiples of the smallest primes
- We know, that the primes, except 2 and 3,
can occur only for those numbers which have modulo 6 a remainder 1 or 5.
So we can avoid to cross out all multiples of 2 and 3, saving a
factor of 3 in sieving speed. What is more, this list of smallest primes can
be extended, e.g. including 5 and 7, and we need only to consider 48 numbers out
of 210, achieving a speed-up factor of even 4.375. Each further small prime p will decrease the run time by a factor 1-1/p, but increase the code of
the program by a factor p-1.
- Choose an appropriate sieve size
- Typically, the sieve should fit into the computers main memory and even
better into its cache in modern high speed computers. Therefore, one can't use
a sieve of the size of the sieve limit, but must use far smaller sieve sizes normally. So, one has to choose an appropriate fixed sieve size and sieve the total
range in many parts sequentially. And hence, the dense bit packing in the sieve
pays very well!
Thanks to Thomas Fiedler, University of Jena, who discovered in May 2003 an important bug (a 1 not a 0 should have been there) when segmentating sieving, I polished the source a bit
and thus you can fetch the latest prime_sieve.c version 2.0c. And here is the corresponding README.
- source code availible
- very fast
- interval sieving possible
- adjustable to CPU cache size
- works up to numbers 264
- user definable macro called for each found prime number
CPU1: HP PA-8000 180MHz with 400 MB RAM (256 KB Data-Cache) running HP-UX 10.20 (sieve size=200KB).
| Limit || Prime Count || CPU1 || CPU2 || CPU3 || CPU4 || CPU5 || CPU6 || CPU7 || CPU8 || CPU9 || Factor|
| 10^2 || 25|| 0.0 s||0.0 s|| 0.00 s||0.0 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s||1.0955|
| 10^3 || 168|| 0.0 s||0.0 s|| 0.00 s||0.0 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s||1.5010|
| 10^4 || 1229|| 0.0 s||0.1 s|| 0.00 s||0.0 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s||1.7887|
| 2^16 || 6542|| 0.0 s||0.1 s|| 0.01 s / 0.01 s||0.0 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s||1.9744|
| 10^5 || 9592|| 0.1 s||0.1 s|| 0.01 s / 0.01 s||0.0 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s|| 0.00 s||2.0118|
| 10^6 || 78498|| 0.1 s||0.2 s|| 0.02 s / 0.03 s||0.1 s|| 0.01 s|| 0.01 s|| 0.01 s/ 0.01 s|| 0.00 s|| 0.00 s||2.1941|
| 10^7 || 664579|| 0.2 s||1.6 s|| 0.14 s / 0.20 s||0.5 s|| 0.13 s|| 0.08 s|| 0.04 s/ 0.04 s|| 0.02 s|| 0.01 s||2.3483|
| 10^8 || 5761455|| 1.2 s||17.0 s|| 1.42 s / 2.02 s||4.9 s|| 1.36 s|| 0.80 s|| 0.36 s/ 0.37 s|| 0.18 s|| 0.11 s||2.4818|
| 10^9 || 50847534|| 11.3 s||187.8 s|| 16.2 s / 21.7 s||51.3 s|| 15.30 s|| 8.84 s|| 3.62 s/ 3.68 s|| 1.55 s|| 1.16 s||2.5996|
| 2^32 || 203280221|| 50.7 s||889.5 s|| 79.6 s / 104.7 s||249.5 s|| 73.85 s|| 43.01 s|| 15.97 s/ 15.98 s|| 7.55 s|| 5.14 s||2.6676|
| 10^10 || 455052511|| 120.4 s|| 268.9 s|| 191.35 s|| 38.49 s|| 16.72 s|| 12.34 s||2.7050|
| 10^11 ||4118054813||1268.6 s|| 4122.7 s|| || 482.77 s|| 214.51 s|| 143.71 s||2.8003|
| 10^12 ||37607912018||15207.7 s|| || 7466.49 s|| 3071.43 s|| 2074.49 s||2.8873|
| 10^13 ||346065536839||249032.9 s|| || 32327.34 s|| 30955.69 s||2.9673|
CPU2: MIPS 3000 33MHz with 32 MB RAM (no Cache) running Ultrix V4.4 (sieve size=15KB).
CPU3: AMD K6 233MHz with 64 MB RAM (32 KB Data-Cache) running Linux 2.032 (sieve size=22KB).
The C-source was compiled using gcc 22.214.171.124 for i486-linux one time for 32bit LONG and the other time for 64 bit LONG. Further, for limit > 2^32 one should
increase the sieve size to get shorter running times.
CPU4: Intel Pentium 133MHz with 64 MB RAM (8KB Data-Cache) running Windows 95 (sieve size=8000B).
Compiler: Visual C++ (max speed)
CPU5: DEC Alpha 21164a 400 MHz with 64 MB RAM (8 KB Data-Cache) running OSF1 V4.0 (sieve size=8000)
CPU6: Intel Pentium III 450 MHz with 128 MB RAM (16 KB Data-Cache) running Linux 2.2.14 using gcc 126.96.36.199 (i386 Linux/ELF) (sieve size=16384).
As you see, it is very important how well the code-optimizer and the caching logic of the cpu does. The sieve size are nearly optimal chosen for limits < 10^10.
CPU7: AMD Thunderbird 900 MHz with 256 MB RAM (64 KB 1st level Data-Cache) running Linux 2.2.19 using gcc 2.95.2 (i386 Linux/ELF) (sieve size=64000/64KB).
CPU8: PowerPC 970FX 2.5 GHz with 1.5 GB RAM running Mac OSX 10.3.8 using
compiler IBM XLF 6.0 Advanced Edition (sieve size=32000 for limit <= 10^11 else
the minimal necessary sieve size).
CPU9: AMD Athlon64 Winchester 2 GHz with 3 GB RAM (64 KB 1st level Data-Cache)
running Linux 2.6.9 using gcc 3.4.2 (x86-64 Linux/ELF) (sieve size=65000).
Factor = ln(1/2 ln(Limit))+0.2615
The average access for each bit in the sieve is PROD(1-1/p) (Factor - SUM1/p) whereby the primes p in the sum and the product runs over the smallest not-bother-primes, --- here 2,3,5, resulting in 8/30(Factor -31/30).
BTW: Because the gaps between successive primes are <= 250 up to p=436273009 and
<= 500 up to 304599508537, to hold a list of primes only their differences
need to be stored in a byte.
For interested persons: the frequency of primes
and a little problem for the mathematicians: estimate the magnitude of
SUMp<=n 1/p - ln(ln(n))-0.2614972128....
Hardy & Wright tell us O(1/ln(n)), but this seems to be too pessimisticly.
For intervals larger about 10^9, surely for those > 10^10, the Sieve of Eratosthenes is outperformed
by the Sieve of Atkins and Bernstein which uses irreducible binary quadratic forms. See their paper for background informations as well as paragraph 5 of W. Galway's Ph.D. thesis.
created: 1998-06-02 17:30 UTC+2
updated: 2005-05-19 17:10 UTC+2 | <urn:uuid:4d6e491a-050c-44e9-af3a-76dc3e6affaf> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422115868812.73/warc/CC-MAIN-20150124161108-00213-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 3,
"language": "en",
"language_score": 0.7546849250793457,
"score": 3.15625,
"token_count": 2776,
"url": "http://wwwhomes.uni-bielefeld.de/achim/prime_sieve.html"
} |
From Wikipedia, the free encyclopedia
Schematic diagram of the planned rover components.
The Mars Science Laboratory (MSL), known as Curiosity, is a NASA rover scheduled to be launched in October 2011 and would perform the first-ever precision landing on Mars. It is a rover that will assess whether Mars ever was, or is still today, an environment able to support microbial life. In other words, its mission is to determine the planet's habitability. It will also analyze samples scooped up from the soil and drilled powders from rocks.
The MSL rover will be over five times as heavy and carry over ten times the weight in scientific instruments as the Spirit or Opportunity rovers. The United States, Canada, Germany, France, Russia and Spain will provide the instruments on board. The MSL rover will be launched by an Atlas V 541 rocket and will be expected to operate for at least 1 Martian year (668 Martian sols/686 Earth days) as it explores with greater range than any previous Mars rover.
Mars Science Laboratory is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of Mars, and is a project managed by NASA's Jet Propulsion Laboratory. The total cost of the MSL project is about $2.3 billion USD.
Goals and objectives
The MSL has four goals: To determine if life ever arose on Mars, to characterize the climate of Mars, to characterize the geology of Mars, and to prepare for human exploration. To contribute to the four science goals and meet its specific goal of determining Mars' habitability, Mars Science Laboratory has eight scientific objectives:
- Determine the nature and inventory of organic carbon compounds.
- Inventory the chemical building blocks of life as we know it: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
- Identify features that may represent the effects of biological processes.
- Investigate the chemical, isotopic, and mineralogical composition of the Martian surface and near-surface geological materials.
- Interpret the processes that have formed and modified rocks and soils.
- Assess long-timescale (i.e., 4-billion-year) Martian atmospheric evolution processes.
- Determine present state, distribution, and cycling of water and carbon dioxide.
- Characterize the broad spectrum of surface radiation, including galactic radiation, cosmic radiation, solar proton events and secondary neutrons.
In September 2006, MSL was approved by NASA for a 2009 launch.
In April 2008, it was reported that the project was $235 million USD, or 24% over budget and that the money to compensate this overrun may have to come from other NASA Mars missions.
In October 2008, MSL was getting closer to a 30% cost overrun.
On November 19, 2008, NASA announced that MSL project leaders at the Jet Propulsion Laboratory (JPL) had reduced the list of candidate landing sites to four: Eberswalde, Gale, Holden, Mawrth.
As of November 2008, development is essentially finished, much of MSL hardware and software are complete and testing is ongoing.
On December 3, 2008, NASA announced that the MSL launch will be delayed until the fall of 2011 because of inadequate test time. The technical and budgetary reasons behind the delay were explained to the Planetary Science Community in a January 2009 meeting at NASA Headquarters.
From March 23–29, 2009, the general public had an opportunity to rank nine finalist names through a public poll on the NASA website as additional input for judges to consider during the MSL name selection process. On May 27, 2009, the winning name of Curiosity, which was submitted by a sixth-grader, Clara Ma, from Kansas was chosen.
The MSL will have a length of 9 feet (2.7 m) and weigh 1,984 pounds (900 kg) including 176 pounds (80 kg) of scientific instruments. It will be the same size as a Mini Cooper automobile. This compares to the Mars Exploration Rovers which have a length of 5 feet 2 inches (1.57 m) and weigh 384 pounds (174 kg) including 15 pounds (6.8 kg) of scientific instruments.
Once on the surface, the MSL rover will be able to roll over obstacles approaching 75 centimeters (30 in) high. Maximum terrain-traverse speed is estimated to be 90 meters (300 ft) per hour via automatic navigation, however, average traverse speeds will likely be about 30 meters (100 ft) per hour, based on variables including power levels, difficulty of the terrain, slippage, and visibility. MSL is expected to traverse a minimum of 12 miles (19 km) in its two-year mission.
The MSL will be powered by radioisotope thermoelectric generators (RTGs), as used by the successful Mars landers Viking 1 and Viking 2 in 1976. Radioisotope power systems are generators that produce electricity from the natural decay of plutonium-238, which is a non-weapons-grade form of that radioisotope used in power systems for NASA spacecraft. Heat given off by the natural decay of this isotope is converted into electricity, providing constant power during all seasons and through the day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.
The MSL power source will use the latest RTG generation built by Boeing, called the "Multi-Mission Radioisotope Thermoelectric Generator" (MMRTG). The MMRTG is a flexible and compact power system under development that is based on conventional RTGs. The MMRTG is designed to produce 125 watts of electrical power at the start of the mission and 100 watts after 14 years. The MSL will generate 2.5 kilowatt hours per day compared to the Mars Exploration Rovers which can generate about 0.6 kilowatt hours per day. Although the primary mission is planned to last about 2 Earth years, the MMRTG will have a minimum lifetime of 14 years.
Heat Rejection System
The temperatures in the potential areas that the MSL might land at can vary from +86°F to −197°F (+30 to −127°C). Therefore, the Heat Rejection System (HRS) uses fluid pumped through 200 feet of tubes in the MSL body so that sensitive components are kept at optimal temperatures. Other methods of heating the internal components include using radiated heat generated from the components in the craft itself, as well as excess heat from the MMRTG unit. The HRS also has the ability to cool components if necessary.
The two identical on-board rover computers, called "Rover Electronics Module" (REM), contain radiation hardened memory to tolerate the extreme radiation environment from space and to safeguard against power-off cycles. Each computer's memory includes 256 kB of EEPROM, 256 MB of DRAM, and 2 GB of flash memory. This compares to 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory used in the Mars Exploration Rovers.
The REM computers use the RAD750 CPU which is a successor to the RAD6000 CPU used in the Mars Exploration Rovers. The RAD750 CPU is capable of up to 400 MIPS while the RAD6000 CPU is capable of up to 35 MIPS.
The rover has an Inertial Measurement Unit (IMU) that provides 3-axis information on its position which is used in rover navigation. The rover's computers are constantly self-monitoring itself to keep the rover operational, such as by regulating the rover's temperature. Activities such as taking pictures, driving, and operating the instruments are performed in a command sequence that is sent from the flight team to the rover. In the event of problems with the main computer, the backup computer will take over.
At present, 10 instruments have been selected for development or production for the Mars Science Laboratory rover:
Cameras (MastCam, MAHLI, MARDI)
The MastCam, MAHLI, and MARDI cameras are being developed by Malin Space Science Systems and they all share common design components, such as on-board electronic imaging processing boxes, 1600x1200 CCDs, and a RGB Bayer pattern filter.
- MastCam: This system will provide multiple spectra and true color imaging with two cameras. The cameras can take true color images at 1200x1200 pixels and up to 10 frames per second hardware-compressed, high-definition video at 720p (1280x720). One camera will be the Medium Angle Camera (MAC) which has a 34 mm focal length, a 15 degree field of view, and can yield 22 cm/pixel scale at 1 km. The other camera will be the Narrow Angle Camera (NAC) which has a 100 mm focal length, a 5.1-degree field of view, and can yield 7.4 cm/pixel scale at 1 km. Each camera will have 8 GB of flash memory, which is capable of storing over 5,500 raw images, and can apply real time lossless or JPEG compression. The cameras have an autofocus capability which allows them to focus on objects from 2.1 meters (6.9 ft) to infinity. Each camera will also have a RGB Bayer pattern filter with 8 filter positions. In comparison to the 1024x1024 black & white panoramic cameras used on the Mars Exploration Rover (MER) the MAC MastCam will have 1.25X higher spatial resolution and the NAC MastCam will have 3.67X higher spatial resolution.
- Mars Hand Lens Imager (MAHLI): This system will consist of a camera mounted to a robotic arm on the rover. It will be used to acquire microscopic images of rock and soil. MAHLI can take true color images at 1600x1200 pixels with a resolution as high as 14.5 micrometers per pixel. MAHLI has a 18.3 mm to 21.3 mm focal length and a 33.8 to 38.5 degree field of view. MAHLI will have both white and UV LED illumination for imaging in darkness or imaging fluorescence. MAHLI will also have mechanical focusing in a range from infinite to mm distances. MAHLI can store either the raw images or do real time lossless predictive or JPEG compression.
- MSL Mars Descent Imager (MARDI): During the descent to the Martian surface, MARDI will take color images at 1600x1200 pixels with a 1.3 millisecond exposure time starting at distances of about 3.7 km to near 5 meters from the ground and will take images at a rate of 5 frames per second for about 2 minutes. MARDI has a pixel scale of 1.5 meters at 2 km to 1.5 millimeters at 2 meters and has a 90 degree circular field of view. MARDI will have 8 GB of internal buffer memory which is capable of storing over 4,000 raw images. MARDI imaging will allow the mapping of surrounding terrain and the location of landing.
ChemCam is a suite of remote sensing instruments, including the first laser-induced breakdown spectroscopy (LIBS) system to be used for planetary science and a remote micro-imager (RMI). The LIBS instrument can target a rock or soil sample from up to 7 meters away, vaporizing a small amount of it and then collecting a spectrum of the light emitted by the vaporized rock. An infrared laser with 1067 nm wavelength and a 5 nanosecond pulse will focus on a sub-millimeter spot with a power in excess of 10 megawatts, depositing 15mJ of energy. Detection of the ball of luminous plasma will be done in the visible and near-UV and near-IR range, between 240 nm and 800 nm. Using the same collection optics, the RMI provides context images of the LIBS analysis spots. The RMI resolves 1 mm objects at 10 m distance, and has a field of view covering 20 cm at that distance. The ChemCam instrument suite is being developed by the Los Alamos National Laboratory and the French CESR laboratory. NASA's cost for ChemCam is approximately $10M, including an overrun of about $1.5M , a very tiny fraction of the total mission costs. The flight model of the Mast Unit was delivered from the French CNES to Los Alamos National Laboratory and was able to deliver the engineering model to JPL in February 2008.
Alpha-particle X-ray spectrometer (APXS)
This device will irradiate samples with alpha particles and map the spectra of X-rays that are reemitted for determining the elemental composition of samples. It is being developed by the Canadian Space Agency. The APXS is a form of PIXE, which has previously been used by the Mars Pathfinder and the Mars Exploration Rovers.
Chemin stands for "Chemistry and Mineralogy" and is a X-Ray Diffraction/X-Ray Fluorescence Instrument. CheMin is a X-ray diffraction/X-ray fluorescence instrument that will quantify minerals and mineral structure of samples. It is being developed by Dr. David Blake at NASA Ames Research Center and the NASA's Jet Propulsion Laboratory.
Sample Analysis at Mars (SAM)
The SAM instrument suite will analyze organics and gases from both atmospheric and solid samples. It is being developed by the NASA Goddard Space Flight Center, the Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA) of France's CNRS and Honeybee Robotics, along with many additional external partners. The SAM suite consists of three instruments:
- Quadrupole Mass Spectrometer (QMS)
- Gas Chromatograph (GC)
- Tunable Laser Spectrometer (TLS)
The Quadrupole Mass Spectrometer (QMS) will detect gases sampled from the atmosphere or those released from solid samples by heating. The Gas Chromatograph (GC) will be used to separate out individual gases from a complex mixture into molecular components with a mass range of 2–235 u. The Tunable Laser Spectrometer (TLS) will perform precision measurements of oxygen and carbon isotope ratios in carbon dioxide (CO2) and methane (CH4) in the atmosphere of Mars in order to distinguish between a geochemical and a biological origin.
The SAM also has three subsystems: The Chemical Separation and Processing Laboratory (CSPL), for enrichment and derivatization of the organic molecules of the sample; the Sample Manipulation System (SMS) for transporting powder delivered from the MSL drill to a SAM inlet and into one of 74 sample cups. The SMS then moves the sample to the SAM oven to release gases by heating to up to 1000 oC; and the Wide Range Pumps (WRP) subsystem to purge the QMS, TLS, and the CPSL.
Radiation Assessment Detector (RAD)
This instrument will characterize the broad spectrum of radiation found near the surface of Mars for purposes of determining the viability and shielding needs for human explorers. Funded by the Exploration Systems Mission Directorate at NASA Headquarters and developed by Southwest Research Institute (SwRI) and the extraterrestrial physics group at Christian-Albrechts-Universität zu Kiel, Germany.
Dynamic Albedo of Neutrons (DAN)
A pulsed neutron source and detector for measuring hydrogen or ice and water at or near the Martian surface, provided by the Russian Federal Space Agency.
Rover Environmental Monitoring Station (REMS)
Meteorological package and an ultraviolet sensor provided by the Spanish Ministry of Education and Science. It will be mounted on the camera mast and measure atmospheric pressure, humidity, wind currents and direction, air and ground temperature and ultraviolet radiation levels.
MSL Entry Descent and Landing Instrumentation (MEDLI)
The MEDLI project’s main objective is to measure aerothermal environments, sub-surface heat shield material response, vehicle orientation, and atmospheric density for the atmospheric entry through the sensible atmosphere down to heat shield separation of the Mars Science Laboratory entry vehicle. The MEDLI instrumentation suite will be installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars missions by providing measured atmospheric data to validate Mars atmosphere models and clarify the design margins on future Mars missions. MEDLI instrumentation consists of three main subsystems: MEDLI Integrated Sensor Plugs (MISP), Mars Entry Atmospheric Data System (MEADS) and the Sensor Support Electronics (SSE).
Hazard Avoidance Cameras (Hazcams)
The MSL will use four pairs of black and white navigation cameras located on the front left and right and rear left and right of the rover. The Hazard Avoidance Cameras (also called Hazcams) are used for autonomous hazard avoidance during rover drives and for safe positioning of the robotic arm on rocks and soils. The cameras will use visible light to capture three-dimensional (3-D) imagery. The cameras have a 120 degree field of view and map the terrain at up to 10 feet (3 meters) in front of the rover. This imagery safeguards against the rover inadvertently crashing into unexpected obstacles, and works in tandem with software that allows the rover to make its own safety choices.
The MSL will use two pairs of black and white navigation cameras mounted on the mast to support ground navigation. The cameras will use visible light to capture three-dimensional (3-D) imagery. The cameras have a 45 degree field of view.
The MSL will be launched using the Atlas V 541 which is a two stage rocket capable of launching up to 17,597 pounds (8,672 kg) to geostationary transfer orbit. The Atlas V has also been used to launch the Mars Reconnaissance Orbiter and New Horizons.
MSL landing diagram for outside Martian atmosphere and for entry.
MSL landing diagram for parachute descent, powered descent, and sky crane.
Landing a large mass on Mars is a difficult challenge: the atmosphere is thick enough to prevent rockets being used to provide significant deceleration, but too thin for parachutes and aerobraking alone to be effective. Although some previous missions have used airbags to cushion the shock of landing, the MSL is too large for this to be an option.
It is planned that the MSL will perform the first-ever precision landing on Mars by demonstrating the ability to land within a predetermined 20 km (12.4 miles) landing ellipse. For this, the MSL will employ a combination of several systems in a precise order, where the entry, descent and landing sequence will break down into four parts.
- Guided entry - The MSL will be set down on the Martian surface using a new high-precision entry, descent, and landing (EDL) system that will place it in a 20 kilometer (12 mile) landing ellipse, in contrast to the 150 kilometer by 20 kilometer (about 93 miles by 12 miles) landing ellipse of the landing systems used by the Mars Exploration Rovers. The rover is folded up within an aeroshell which protects it during the travel through space and during the atmospheric entry at Mars. Much of the reduction of the landing precision error is accomplished by an entry guidance algorithm, similar to that used by the astronauts returning to Earth in the Apollo space program. This guidance uses the lifting force experienced by the aeroshell to "fly out" any detected error in range and thereby arrive at the targeted landing site. In order for the aeroshell to have lift, its center of mass is offset from the axial centerline which results in an off-center trim angle in atmospheric flight, again similar to the Apollo Command Module. This is accomplished by a series of ejectable ballast masses. The lift vector is controlled by four sets of two Reaction Control System (RCS) thrusters that produce approximately 500 N of thrust per pair. This ability to change the pointing of the direction of lift allows the spacecraft to react to the ambient environment, and steer toward the landing zone.
The MSL test parachute. Note the people in the lower-right corner of the image.
- Parachute descent - Like Viking, Mars Pathfinder and the Mars Exploration Rovers, the Mars Science Laboratory will be slowed by a large parachute. After the entry phase is complete and the capsule has slowed to Mach 2, a supersonic parachute is deployed. The entry vehicle must first eject the ballast mass such that the center of gravity offset is removed. In March and April 2009 the parachute for the MSL was tested in the world's largest wind tunnel and passed flight-qualification testing. The parachute has 80 suspension lines, is over 165 feet (50 meters) long, and is about 51 feet (16 meters) in diameter. The parachute is capable of being deployed at Mach 2.2 and can generate up to 65,000 pounds of drag force in the Martian atmosphere.
- Powered descent - Following the parachute braking, the rover and descent stage drop out of the aeroshell. The descent stage is a platform above the rover with variable thrust mono propellant hydrazine rocket thrusters on arms extending around this platform to slow the descent. Meanwhile, the rover itself is being transformed from its stowed flight configuration to a landing configuration while being lowered beneath the descent stage by the "sky crane" system.
- Sky Crane - Like a large crane on Earth, the sky crane system will lower the rover to a "soft landing"–wheels down–on the surface of Mars. This consists of 3 bridles lowering the rover itself and an umbilical cable carrying electrical signals between the descent stage and rover. At roughly 7.5 meters below the descent stage the "sky crane" system slows to a halt and the rover touches down. After the rover touches down it waits 2 seconds to confirm that it is on solid ground and fires several pyros (small explosive devices) activating cable cutters on the bridle and umbilical cords to free itself from the descent stage. The descent stage promptly flies away to a crash landing, and the rover gets ready to roam Mars. The planned "sky crane" powered descent landing system has never been used in actual missions before.
Proposed landing sites
The essential issue when selecting an optimum landing site, is to identify a particular geologic environment, or set of environments, that would support microbial life. To mitigate the risk of disappointment and ensure the greatest chance for science success, interest is placed at the greatest number of possible science objectives at a chosen landing site. Thus, a landing site with morphologic and mineralogic evidence for past water, is better than a site with just one of these criteria. Furthermore, a site with spectra indicating multiple hydrated minerals is preferred; clay minerals and sulfate salts would constitute a rich site. Hematite, other iron oxides, sulfate minerals, silicate minerals, silica, and possibly chloride minerals have all been suggested as possible substrates for fossil preservation. Indeed, all are known to facilitate the preservation of fossil morphologies and molecules on Earth. Difficult terrain is the best candidate for finding evidence of livable conditions, and engineers must be sure the rover can safely reach the site and drive within it.
The current engineering constraints call for a landing site less than 45° from the Martian equator, and less than 1 km above the reference datum. At the first MSL Landing Site workshop, 33 potential landing sites were identified. By the second workshop in late 2007, the list had grown to include almost 50 sites, and by the end of the workshop, the list was reduced to six; in November 2008, project leaders at a third workshop reduced the list to four landing sites.
On August 20, 2009, NASA sent out a call for additional landing site proposals. The new proposals will be evaluated and reviewed until the summer of 2010. A fourth landing site workshop, taking both the new and existing proposals into account, is planned for September 2010. The fifth and final workshop is planned for March 2011.
- ^ a b c "Name NASA's Next Mars Rover". NASA/JPL. 2009-05-27. http://marsrovername.jpl.nasa.gov/. Retrieved 2009-05-27.
- ^ a b "NASA Selects Student's Entry as New Mars Rover Name". NASA/JPL. 2009-05-27. http://www.nasa.gov/mission_pages/msl/msl-20090527.html. Retrieved 2009-05-27.
- ^ "NASA's Shuttle and Rocket Launch Schedule". NASA. 2009-05-27. http://www.nasa.gov/missions/highlights/schedule.html. Retrieved 2010-03-12.
- ^ "Mars Science Laboratory: Mission". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/. Retrieved 2010-03-12.
- ^ a b c d e "Troubles parallel ambitions in NASA Mars project". USA Today. 2008-04-14. http://www.usatoday.com/tech/science/space/2008-04-13-mars_N.htm. Retrieved 2009-05-27.
- ^ "NASA Delays Next Mars Rover Mission". The New York Times. 2008-12-04. http://www.nytimes.com/2008/12/05/science/space/05mars.html. Retrieved 2009-05-27.
- ^ "Science Objectives of the MSL". JPL. NASA. http://marsprogram.jpl.nasa.gov/msl/science/objectives.html. Retrieved 2009-05-27.
- ^ Mars Science Laboratory Mission Profile
- ^ Frank Morring; Jefferson Morris (2008-10-03). "Mars Science Lab In Doubt". Aviation Week. http://www.aviationweek.com/aw/generic/story.jsp?id=news/Balloon100308.xml&headline=Mars%20Science%20Lab%20In%20Doubt&channel=space. Retrieved 2009-05-27.
- ^ Mars Science Laboratory: Still Alive, For Now. 10 October 2008. Universe Today.
- ^ http://www.marstoday.com/news/viewpr.rss.html?pid=26970
- ^ MSL Technical and Replan Status. Richard Cook. (January 9, 2009)
- ^ "Next NASA Mars Mission Rescheduled For 2011". NASA/JPL. 2008-12-04. http://marsprogram.jpl.nasa.gov/msl/newsroom/pressreleases/20081204a.html. Retrieved 2008-12-04.
- ^ "Mars Science Laboratory: the budgetary reasons behind its delay". The Space Review. 2009-3-02. http://www.thespacereview.com/article/1318/1. Retrieved 2010-1-26.
- ^ "Mars Science Laboratory: the technical reasons behind its delay". The Space Review. 2009-3-02. http://www.thespacereview.com/article/1319/1. Retrieved 2010-1-26.
- ^ "NASA Invites Students to Name New Mars Rover". NASA/JPL. 2008-11-18. http://www.nasa.gov/mission_pages/mars/news/msl-20081118.html. Retrieved 2009-05-27.
- ^ http://news.bbc.co.uk/1/hi/sci/tech/7664965.stm
- ^ A YouTube video shows a MSL mockup compared to the Mars Exploration Rover and Sojourner Rover. "Mars Rovers". YouTube. 2008-04-12. http://www.youtube.com/watch?v=D7kBTZAGhbs. Retrieved 2008-09-12.
- ^ "Mars Science Laboratory — Homepage". NASA. http://marsprogram.jpl.nasa.gov/msl/overview/. Retrieved 2008-10-07.
- ^ a b "Multi-Mission Radioisotope Thermoelectric Generator". NASA/JPL. 2008-01-01. http://www.ne.doe.gov/pdfFiles/MMRTG_Jan2008.pdf. Retrieved 2009-09-07.
- ^ a b "Mars Exploration: Radioisotope Power and Heating for Mars Surface Exploration". NASA/JPL. 2006-04-18. http://www.jpl.nasa.gov/news/fact_sheets/mars-power-heating.pdf. Retrieved 2009-09-07.
- ^ a b "Technologies of Broad Benefit: Power". http://marsprogram.jpl.nasa.gov/msl/technology/tech_power.html. Retrieved 2008-09-20.
- ^ Ajay K. Misra (2006-06-26). "Overview of NASA Program on Development of Radioisotope Power Systems with High Specific Power". NASA/JPL. http://pdf.aiaa.org/preview/CDReadyMIECEC06_1309/PV2006_4187.pdf. Retrieved 2009-05-12.
- ^ "Mars Science Laboratory: Technologies of Broad Benefit: Power". NASA/JPL. http://mars.jpl.nasa.gov/msl/technology/tech_power.html. Retrieved 2009-03-28.
- ^ "Keeping it Cool (...or Warm!)". NASA/JPL. 2009-08-09. http://www1.nasa.gov/mission_pages/mars/images/20081209_msl.html. Retrieved 2009-08-09.
- ^ "In-situ Exploration and Sample Return: Technologies for Severe Environments". NASA/JPL. http://mars.jpl.nasa.gov/msl/technology/tech_serv_env.html. Retrieved 2008-12-11.
- ^ a b c d e "Mars Science Laboratory: Mission: Rover: Brains". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/rover/brains/. Retrieved 2009-03-27.
- ^ Max Bajracharya, Mark W. Maimone, and Daniel Helmick (2008) (Jet Propulsion Laboratory and California Institute of Technology); Autonomy for Mars rovers: past, present, and future; published in: Computer, a journal of the IEEE Computer Society, December 2008, Volume 41, Number 12, page 45, ISSN 0018-9162.
- ^ "BAE SYSTEMS COMPUTERS TO MANAGE DATA PROCESSING AND COMMAND FOR UPCOMING SATELLITE MISSIONS". BAE Systems. 2008-06-17. http://www.baesystems.com/Newsroom/NewsReleases/autoGen_108517143749.html. Retrieved 2008-11-17.
- ^ "E&ISNow — Media gets closer look at Manassas". BAE Systems. 2008-08-01. http://www.baesystems.com/BAEProd/groups/public/documents/bae_publication/bae_pdf_eis_2008-08-1.pdf. Retrieved 2008-11-17.
- ^ "RAD750 radiation-hardened PowerPC microprocessor" (PDF). BAE Systems. 2008-07-01. http://www.baesystems.com/BAEProd/groups/public/@businesses/@eandis/documents/bae_publication/bae_pdf_eis_rad750_pwr_pc_mp.pdf. Retrieved 2009-09-07.
- ^ "RAD6000 Space Computers" (PDF). BAE Systems. 2008-06-23. http://www.baesystems.com/BAEProd/groups/public/documents/bae_publication/bae_pdf_eis_sfrwre.pdf. Retrieved 2009-09-07.
- ^ a b c d e f g "Mast Camera (Mastcam)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/Mastcam/. Retrieved 2009-03-18.
- ^ a b c d e f g "Mars Hand Lens Imager (MAHLI)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/MAHLI/. Retrieved 2009-03-23.
- ^ a b c d e "Mars Descent Imager (MARDI)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/MARDI/. Retrieved 2009-04-03.
- ^ a b c "Mars Science Laboratory (MSL): Mast Camera (Mastcam): Instrument Description". Malin Space Science Systems. http://www.msss.com/msl/mastcam/MastCam_description.html. Retrieved 2009-04-19.
- ^ "Mars Science Laboratory Instrumentation Announcement from Alan Stern and Jim Green, NASA Headquarters". SpaceRef Interactive. http://www.marstoday.com/news/viewsr.html?pid=25991.
- ^ "Mars Descent Imager (MARDI) Update". Malin Space Science Systems. November 12, 2007. http://www.msss.com/msl/mardi/news/12Nov07/index.html.
- ^ a b c d e f g "MSL Science Corner: Chemistry & Camera (ChemCam)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/ChemCam/. Retrieved 2009-09-09.
- ^ Spacecraft: Surface Operations Configuration: Science Instruments: ChemCam
- ^ Salle B., Lacour J. L., Mauchien P., Fichet P., Maurice S., Manhes G. (2006). "Comparative study of different methodologies for quantitative rock analysis by Laser-Induced Breakdown Spectroscopy in a simulated Martian atmosphere" (PDF). Spectrochimica Acta Part B-Atomic Spectroscopy 61 (3): 301–313. doi:10.1016/j.sab.2006.02.003. http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1580.pdf.
- ^ CESR presentation on the LIBS
- ^ ChemCam fact sheet
- ^ Wiens R.C., Maurice S. (2008). "Corrections and Clarifications, News of the Week". Science 322 (5907): 1466. doi:10.1126/science.322.5907.1466a. http://www.sciencemag.org.
- ^ Wiens R.C., Maurice S. (2008). "ChemCam's Cost a Drop in the Mars Bucket". Science 322 (5907): 1464. doi:10.1126/science.322.5907.1464a. http://www.sciencemag.org.
- ^ ChemCam Status April, 2008
- ^ a b c "MSL Science Corner: Alpha Particle X-ray Spectrometer (APXS)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/APXS/. Retrieved 2009-09-09.
- ^ R. Rieder, R. Gellert, J. Brückner, G. Klingelhöfer, G. Dreibus, A. Yen, S. W. Squyres (2003). "The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers". J. Geophysical Research 108: 8066. doi:10.1029/2003JE002150.
- ^ a b c "MSL Science Corner: Chemistry & Mineralogy (CheMin)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/CheMin/. Retrieved 2009-09-09.
- ^ Sarrazin P., Blake D., Feldman S., Chipera S., Vaniman D., Bish D. (2005). "Field deployment of a portable X-ray diffraction/X-ray flourescence instrument on Mars analog terrain". Powder Diffraction 20 (2): 128–133. doi:10.1154/1.1913719.
- ^ a b c d e f g "MSL Science Corner: Sample Analysis at Mars (SAM)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/SAM/. Retrieved 2009-09-09.
- ^ Overview of the SAM instrument suite
- ^ Cabane M., Coll P., Szopa C., Israel G., Raulin F., Sternberg R., Mahaffy P., Person A., Rodier C., Navarro-Gonzalez R., Niemann H., Harpold D., Brinckerhoff W. (2004). "Did life exist on Mars? Search for organic and inorganic signatures, one of the goals for "SAM" (sample analysis at Mars)". Source: Mercury, Mars and Saturn Advances in Space Research 33 (12): 2240–2245.
- ^ a b "Sample Analysis at Mars (SAM) Instrument Suite". NASA. October 2008. http://ael.gsfc.nasa.gov/marsSAM.shtml. Retrieved 2008-10-09.
- ^ Tenenbaum, David (June 09, 2008):). "Making Sense of Mars Methane". Astrobiology Magazine. http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2765&mode=thread&order=0&thold=0. Retrieved 2008-10-08.
- ^ Tarsitano, C.G. and Webster, C.R. (2007). "Multilaser Herriott cell for planetary tunable laser spectrometers". Applied Optics, 46 (28): 6923–6935. doi:10.1364/AO.46.006923.
- ^ Tom Kennedy and Erik Mumm, Tom Myrick , Seth Frader-Thompson. "OPTIMIZATION OF A MARS SAMPLE MANIPULATION SYSTEM THROUGH CONCENTRATED FUNCTIONALITY" (PDF). http://pdf.aiaa.org/preview/CDReadyMSPACE06_1393/PV2006_7402.pdf.
- ^ a b "MSL Science Corner: Radiation Assessment Detector (RAD)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/RAD/. Retrieved 2009-09-09.
- ^ "MSL Science Corner: Dynamic Albedo of Neutrons (DAN)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/DAN/. Retrieved 2009-09-09.
- ^ a b "MSL Science Corner: Rover Environmental Monitoring Station (REMS)". NASA/JPL. http://msl-scicorner.jpl.nasa.gov/Instruments/REMS/. Retrieved 2009-09-09.
- ^ a b c d Michael Wright (2007-05-01). "Science Overview System Design Review (SDR)". NASA/JPL. http://www.mrc.uidaho.edu/~atkinson/SeniorDesign/ThermEx/MEDLI/MEDLI_SDR_Project_Overview.pdf. Retrieved 2009-09-09.
- ^ a b c d Michael Wright (2007-05-01). "Science Overview System Design Review (SDR)". NASA/JPL. http://www.mrc.uidaho.edu/~atkinson/SeniorDesign/ThermEx/MEDLI/MEDLI_SDR_Science_Overview.pdf. Retrieved 2009-09-09.
- ^ a b c d e "Mars Science Laboratory: Mission: Rover: Eyes and Other Senses: Four Engineering Hazcams (Hazard Avoidance Cameras)". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/rover/eyesandother/. Retrieved 2009-04-04.
- ^ a b "Mars Science Laboratory Rover in the JPL Mars Yard". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/multimedia/interactives/photosynth/. Retrieved 2009-05-10.
- ^ a b c "Mars Science Laboratory: Mission: Rover: Eyes and Other Senses: Two Engineering Navcams (Navigation Cameras)". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/rover/eyesandother/. Retrieved 2009-04-04.
- ^ "Mars Science Laboratory: Mission: Launch Vehicle". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/launchvehicle/. Retrieved 2009-04-01.
- ^ "The Mars Landing Approach: Getting Large Payloads to the Surface of the Red Planet". Universe Today. http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/. Retrieved 2008-10-21.
- ^ "Mission Timeline: Entry, Descent, and Landing". NASA and JPL. http://marsprogram.jpl.nasa.gov/msl/mission/tl_edl.html. Retrieved 2008-10-07.
- ^ "Mars Science Laboratory Entry, Descent, and Landing Triggers". IEEE. http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=04161341. Retrieved 2008-10-21.
- ^ a b c d "Entry, Descent, and Landing". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/timeline/edl/index.html. Retrieved 2009-09-07.
- ^ a b c "Mars Science Laboratory Parachute Qualification Testing". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/news/index.cfm?FuseAction=ShowNews&NewsID=90. Retrieved 2009-04-15.
- ^ Sky crane concept video
- ^ "Landing — Discussion Points and Science Criteria" (Microsoft Word), MSL — Landing Sites Workshop, July 15, http://marsoweb.nas.nasa.gov/landingsites/msl2009/memoranda/sites_jul08/Discussion%20Points-Science%20Criteria.doc, retrieved 2008-10-21
- ^ "Survivor: Mars — Seven Possible MSL Landing Sites". Jet Propulsion Laboratory (NASA). 18 September 2008. http://mars.jpl.nasa.gov/msl/spotlight/20080918.html. Retrieved 2008-10-21.
- ^ "MSL Workshop Summary" (pdf). 2007-04-27. http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/docs/MSL_workshop_summary.pdf. Retrieved 2007-05-29.
- ^ "MSL Landing Site Selection User’s Guide to Engineering Constraints" (pdf). 2006-06-12. http://marsoweb.nas.nasa.gov/landingsites/msl/memoranda/MSL_Eng_User_Guide_v3.pdf. Retrieved 2007-05-29.
- ^ "Second MSL Landing Site Workshop". http://marsoweb.nas.nasa.gov/landingsites/msl2009/workshops/2nd_workshop/2nd_announcement.html.
- ^ "MSL Workshop Voting Chart" (PDF). September 18, 2008. http://marsoweb.nas.nasa.gov/landingsites/msl2009/workshops/3rd_workshop/talks/MSL_Wkshp3_vote_chart.pdf.
- ^ GuyMac. "Reconnaissance of MSL Sites". HiBlog. http://hirise.lpl.arizona.edu/HiBlog/?p=131. Retrieved 2008-10-21.
- ^ "Mars Exploration Science Monthly Newsletter" (PDF). August 1, 2008. http://mepag.jpl.nasa.gov/calendar/MEPAG_Newsletter(08_19C3B3.pdf.
- ^ "Site List Narrows For NASA's Next Mars Landing". MarsToday.com. 2008-11-19. http://www.marstoday.com/news/viewpr.rss.html?pid=26970. Retrieved 2009-04-21.
- ^ http://marsoweb.nas.nasa.gov/landingsites/msl/memoranda/Call_for_new_MSL_Site_8-20-09.doc
- ^ http://mepag.jpl.nasa.gov/calendar/Mars_Explor_Sci_Monthly_Newsltr_12-09.pdf
- ^ "Mars Exploration Program Landing Sites". NASA. http://marsoweb.nas.nasa.gov/landingsites/index.html. Retrieved 2009-04-21.
- ^ "Looking at Landing Sites for the Mars Science Laboratory". YouTube. NASA/JPL. 2009-05-27. http://www.youtube.com/watch?v=sfYK8r6tlrg. Retrieved 2009-05-28.
- ^ "Final 7 Prospective Landing Sites". NASA. February 19, 2009. http://marsoweb.nas.nasa.gov/landingsites/index.html. Retrieved 2009-02-09.
M. K. Lockwood (2006). "Introduction: Mars Science Laboratory: The Next Generation of Mars Landers And The Following 13 articles " (PDF). Journal of Spacecraft and Rockets 43 (2): 257–257. doi:10.2514/1.20678. http://pdf.aiaa.org/jaPreview/JSR/2006/PVJA20678.pdf. | <urn:uuid:7b9d893c-2a1d-4d95-9556-83bc2507ec5c> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422115860277.59/warc/CC-MAIN-20150124161100-00037-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 4,
"language": "en",
"language_score": 0.7975763082504272,
"score": 3.90625,
"token_count": 9954,
"url": "http://www.thefullwiki.org/Mars_Science_Laboratory"
} |
Spooky Projects Introduction to Microcontrollers with Arduino Class 321 Oct 2006 - machineproject - Tod E. Kurt
What’s For Today• Controlling Arduino from a computer• Controlling a computer from Arduino• Servomotors• R,G,B LED color mixing
Remove ProtoShield First half of class, we don’t need it And we want to observe the Arduino board“Shields down, cap’n!”
Recap: Programming Edit Compile Reset UploadRemember: always start from a known working system
Communicating with Others • Arduino can use same USB cable for programming and to talk with computers • Talking to other devices uses the “Serial” commands • Serial.begin() – prepare to use serial • Serial.print() – send data to computer • Serial.read() – read data from computerCan talk to not just computers.Most things more complex than simple sensors/actuators speak serial.
Watch the TX/RX LEDS• TX – sending to PC• RX – receiving from PC• Used when programming or communicating (and keep an eye on that pesky pin13 LED too)
Arduino Says “Hi” “serial_hello_world” • Send “Hello world!” to your computer (and blink LED) • Click on “Serial Monitor” to see output • Watch TX LED compared to pin13 LEDThis sketch is located in the handout, but it’s pretty short.Use on-board pin 13 LED, no need to wire anything up.
Telling Arduino What To Do “serial_read_basic” • You type “H” – LED blinks • In “Serial Monitor” type “H”, press Send • Watch pin 13 LEDThis sketch is in “Examples/serial_comm/serial_read_basic”.Notice how you might not always read something, thus the “-1” check.Can modify it to print “hello world” after it receives something, but before it checks for ‘H’.This way you can verify it’s actually receiving something.
Arduino Communications is just serial communications • Psst, Arduino doesn’t really do USB • It really is “serial”, like old RS-232 serial • All microcontrollers can do serial • Not many can do USB • Serial is easy, USB is hard serial terminal from the olde days
Serial Communications • “Serial” because data is broken down into bits, each sent one-by-one on a single wire: ‘H’ = 0 1 0 0 1 0 0 0 = L H L L H L L L = HIGH LOW • Toggle a pin to send data, just like blinking an LED • Only a single data wire is needed to send data. One other to receive.Note, a single data wire. You still need a ground wire.
Arduino & USB-to-serial Arduino board is really two circuits USB to serial Arduino microcontrollerOriginal Arduino boards were RS-232 serial, not USB.
New Arduino Mini Arduino Mini separates the two circuits Arduino Mini USB adapter Arduino Miniaka. “Arduino Stamp”If you don’t talk with a computer, the USB-to-serial functionality is superfluous.
Arduino to Computer Laptop Arduino board TX USB RX Arduino USB to serial USB to serial programmer driver chip Arduino RX TX microcontroller -OR- Processing sketch -OR- Java program -OR- ... USB is totally optional for Arduino But it makes things easierOriginal Arduino boards were RS-232 serial, not USB.
Arduino & USB • Because Arduino is all about serial, • And not USB, • Interfacing to things like USB flash drives, USB hard disks, USB webcams, etc. is not possibleAlso, USB is a host/peripheral protocol. Being a USB “host” means needing a lot of processingpower and software, not something for a tiny 8kB microcontroller.It can be a peripheral. In fact, there is an open project called “AVR-USB” that allows AVR chips likeused in Arduino to be proper USB peripherals. See: http://www.obdev.at/products/avrusb/
Controlling the Computer • Can send sensor data from Arduino to computer with Serial.print() • There are many different variations to suite your needs:
Controlling the Computer You write one program on Arduino, one on the computer In Arduino: read sensor, send data as byte In Processing: read the byte, do something with itBut writing Processing programs is for another time
Controlling the Computer • Receiving program on the computer can be in any language that knows about serial ports • C/C++, Perl, PHP, Java, Max/MSP, Python, Visual Basic, etc. • Pick your favorite one, write some code for Arduino to controlIf interested, I can give details on just about every language above.
Another Example “serial_read_blink” • Type in a number 1-9 and LED blinks that number • Converts number typed into usable numberThis sketch is also in the handout
Pulse Width Modulation• More commonly called “PWM”• Computers can’t output analog voltages • Only digital voltages (0 volts or 5 volts)• But you can fake it • if you average a digital signal flipping between two voltages.• For example...
PWMOutput voltage is averaged from on vs. off time output_voltage = (on_time / off_time) * max_voltage 5 volts 3.75 Volts 0 volts 75% 25% 75% 25% 75% 25% 5 volts 2.5 Volts 0 volts 50% 50% 50% 50% 50% 50% 5 volts 0 volts 1.0 Volts 20% 80% 20% 80% 20% 80%
PWM• Used everywhere • Lamp dimmers, motor speed control, power supplies, noise making• Three characteristics of PWM signals width • Pulse width range (min/max) • Pulse period (= 1/pulses per second) height • Voltage levels (0-5V, for instance) period
Servomotors • Can be positioned from 0-180º • Internal feedback circuitry & gearing takes care of the hard stuff • Easy three-wire PWM 5V interfaceMore specifically, these are R/C hobby servos used by remote control enthusiastsIn general, “servomotor” is a motor with an inherent feedback mechanism that allows you to sendposition commands to it without requiring you to do the position reading.
Servos, good for what? • Roboticists, movie effects people, and puppeteers use them extensively • Any time you need controlled, repeatable motion • Can turn rotation into linear movement with clever mechanical leversEven clothes use servos now: http://www.technologyreview.com/read_article.aspx?id=17639&ch=infotech
Servos • Come in all sizes 9g • from super-tiny • to drive-your-car • But all have the same 3-wire interface 157ghttp://rctoys.com/http://hobbypeople.net/
Servos Ground (0V)180º Power (+5V) Control (PWM)• PWM freq is 50 Hz (i.e. every 20 millisecs)• Pulse width ranges from 1 to 2 millisecs • 1 millisec = full anti-clockwise position • 2 millisec = full clockwise position
Servo Movement 0 degrees 45 degrees 180 degrees high high high low low low 1000 microseconds 1250 microseconds 2000 microseconds • To position, send a pulse train from 1 to 2 ms • To hold a position, pulses must repeat • Takes time to rotate, so pulse too fast & it won’t move1 millisecond = 1000 microsecondSee http://www.societyofrobots.com/actuators_servos.shtml
Servo Movement 0 degrees 90 degrees 180 degrees 1000 microsecs 1500 microsecs 2000 microsecs In practice, pulse range can be 500 to 2500 microsecs (and go ahead and add a wire marker to your servo like the above)Put the red “arm” on your servo. Needs a philips screwdriver.Many commercial servo drivers have a calibration setting to deal with servo variability
Servo and Arduino First, add somejumper wires to the servo connector
Servo and Arduino Plug power lines in, Plug signal to digital pin 7
Moving a Servo Move the servo across its full range of motion “servo_move_simple” • Uses delayMicroseconds() for pulse width • Uses delay() for pulse frequencySketch is in the handoutCreated a custom function to handle making servo pulsesNew function “delayMicroseconds()”. Like “delay()”, but µsec instead of msec.(and actually, just delaying 20 msec is kinda wrong. should be: 20 - (pulsewidth/1000)
Serial-controlled Servo“servo_serial_simple” Drive the servo by pressing number keys Takes the last servo example and adds the last serial example to it.This sketch is located in the handout.Why that for loop? Because it takes time for the servo to get to a position and it has no memory.
Controlling Arduino • Any program on the computer, not just the Arduino software, can control the Arduino board • On Unixes like Mac OS X & Linux, even the command-line can do it: demo% export PORT=/dev/tty.usbserial-A3000Xv0 demo% stty -f $PORT 9600 raw -parenb -parodd cs8 -hupcl -cstopb clocal demo% printf "1" > $PORT # rotate servo left demo% printf "5" > $PORT # go to middle demo% printf "9" > $PORT # rotate servo rightUnix is rad.
Servo Timing Problems • Two problems with the last sketch • When servoPulse() function runs, nothing else can happen • Servo isn’t given periodic pulses to keep it at positionIf a servo is not being constantly told what to do, it goes slack and doesn’t lift/push/pull
Better Serial Servo“servo_serial_better” Works just like servo_serial_simple (but better) Update the servo when needed, not just when called at the right time Uses “millis()” to know what time it isThis sketch is located in the handout.Trades memory use (the extra variables), for more useful logic.Can call updateServo() as often as you want, servo is only moved when needed.
Multiple Servos• The updateServo() technique can be extended to many servos• Only limit really is number of digital output pins you have• It starts getting tricky after about 8 servos though
Arduino PWM why all the software, doesn’t Arduino have PWM? • Arduino has built-in PWM • On pins 9,10,11 • Use analogWrite(pin,value) • It operates at a high, fixed frequency (thus not usable for servos) • But great for LEDs and motors • Uses built-in PWM circuits of the ATmega8 chip -» no software neededThe PWM speed used for analogWrite() is set to 30 kHz currently.When programming AVRs, PWM speed can be set to just about any value.
R,G,B LEDs Three PWM outputs and three primary colors. Just screams to be made, doesn’t it? Arduino 220 (red,red,brown) or board 330 (orange,orange,brown) pin 11 pin 10 pin 9 gnd With RGB you can red green blue make any color (except black)Put back on the ProtoShield for this.Use either the 220 or 330 ohm resistors in your kit, if you don’t have enough of one or the otherI have lots more 220 if you need them
R,G,B LEDsCut leads of resistors and LEDs to make for a more compact circuit.Also, less likely to short against itself.
RGB Color Fading “dimmingLEDs” Slow color fading and mixing Also outputs the current color values to the serial portThis sketch is located in the handout.It just ramps up and down the red,green,& blue color values and writes them with analogWrite()from http://www.arduino.cc/en/Tutorial/DimmingLEDs
Mood Light Diffuser made from piece of plastic scratched with sandpaperAlso, can use plastic wrap scrunched up to make an interesting diffuser.
Serial-controlled RGB “serial_rgb_led” Send color commands to Arduino e.g. “r200”, “g50”, “b0” Sketch parses what you type, changes LEDs g50This sketch is located in the handout.Color command is two parts: colorCode and colorValuecolorCode is a character, ‘r’, ‘g’, or ‘b’.colorValue is a number between 0-255.Sketch shows rudimentary character string processing in Arduino
Reading Serial Strings • New Serial function in last sketch: “Serial.available()” • Can use it to read all available serial data from computer • Great for reading strings of characters • The “readSerialString()” function at right takes a character string and sticks available serial data into itPay no attention to the pointer symbol (“*”)Must be careful about calling readSerialString() too often or you’ll read partial strings
Going Further • R,G,B LEDS • You can pretty easily replicate the Ambient Orb ($150) functionality • Make a status display for your computer • Computer-controlled accent lighting (a wash of color against the walls)Ambient Orb doesn’t connect to computer though. Uses the pager network.Ambient Devices: http://www.ambientdevices.com/
Going Further • Servos • Mount servo on a video camera – computer-controlled camera motion • Make a robot (a little obvious) • Lots of spooky uses • they’re the core of movie animatronicsI’m not too mechanical, so I don’t have many concrete and still working examples of servo use.
Going Further• Serial communications • Not just for computer-to-Arduino communications • Many other devices speak serial • Older keyboards & mice speak are serial (good for sensors!) • Interface boards (graphic LCDs, servo drivers, RFID readers, Ethernet, Wi-Fi)
Serial Examples to Wi-Fi to Ethernet to graphic LCD to 8-servo controllerLantronix Wi-Port and Lantronix Xport http://lantronix.com/Seetron Serial Graphic display and Mini SSC http://www.seetron.com/slcds.htm http://www.seetron.com/ssc.htm
Serial Examples to Roomba“Hacking Roomba”, out in a few weeks, by me. ;-)http://hackingroomba.com/
Next Week• All about piezos• Building a melody player• Using piezos as pressure & knock sensors• Using Processing with Arduino• Stand-alone Arduino
END Class 3http://todbot.com/blog/spookyarduino Tod E. Kurt email@example.com | <urn:uuid:759f492a-66bc-4a39-9b08-ed80282521df> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422118059355.87/warc/CC-MAIN-20150124164739-00204-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 3,
"language": "en",
"language_score": 0.7984356880187988,
"score": 3.4375,
"token_count": 3333,
"url": "http://www.slideshare.net/anilyanilyadav/arduino-spooky-projectsclass3"
} |
Get the facts on spinal fusion, instrumentation, and grafts
Editor’s note: This is the second article in a two-part series on spinal surgery coding. In this article, we will focus on fusions, instrumentation, and spinal grafts. In part one, we introduced the basic elements of a spinal surgery and took a closer look at decompression procedures.
A surgeon performs an arthrodesis of lumbar vertebrae L1–L2. What are the appropriate codes to report for this procedure? Would it be CPT® code 22612 (arthrodesis, posterior or posterolateral technique, single level; lumbar) or code 22612 and add-on code 22614 (each additional vertebral segment)?
A surgeon performing an arthrodesis fuses two bones together to stabilize the spinal motion unit. It is not possible to fuse a bone to itself, says Kim Pollock, RN, MBA, CPC, consultant and speaker with Karen Zupko & Associates, Inc., in Chicago. The least a surgeon can do is fuse one segment to another.
Here’s where the disconnect between code descriptions and the terminology surgeons use comes into play. Two vertebrae and the tissues that connect them make up the smallest working unit of the spine. This unit is sometimes referred to as a spinal motion unit. To a spinal surgeon, a segment is two movable units. To a coder, a segment indicates one bone.
So when it comes to choosing the correct CPT code for a spinal fusion, coders almost have to count interspaces instead of vertebrae to choose the correct code, Pollock says. For the case above, report only code 22612.
Take into account the reason for the fusion
When coding a spinal fusion, consider the reason for the procedure. Review the documentation to determine whether the physician performed the fusion for deformity, pain, or instability, says Kristi Stumpf, MCS-P, CPC, COSC, ACS-OR, senior orthopedic coder and auditor for The Coding Network based in Beverly Hills, CA.
For a fusion for spinal deformity (e.g., scoliosis or kyphosis), coders should look to codes 22800–22819. This code series was created for, and intended to be used for, fusion procedures performed on younger patients with congenital spinal deformities, not for degenerative scoliosis, says Stumpf.
If the surgeon is performing the fusion for pain or instability, coders should reference one of the following code series:
- 22532–22534 (lateral extracavitary)
- 22548–22585 (anterior or anterolateral)
- 22590–22632 (posterior)
Identify the approach used in the procedure
Surgeons can use various approaches when performing a spinal fusion. Carefully read the documentation to find which approach the surgeon used, then choose the code that reflects that approach. Consider the following approaches:
- Lateral extracavitary (codes 22532–22534)
- Anterior or anterolateral (codes 22558–22585, 22808–22812)
- Posterior or posterolateral or lateral transverse process (codes 22590–22632, 22800– 22804
"Keep in mind that each of these approaches is coded with a different series of codes,” Stumpf says. “You need to understand your approaches. If you don’t, take time to pull them up on the web and see what structures [the surgeon] would be going through, so you can tell exactly what the approach is.” If all else fails, query the physician.
Also note that if the physician documents “direct lateral approach” for spinal fusion, coders should code it as an anterior approach per the North American Spinal Society and the American Association of Neurological Surgeons.
Note the spinal instrumentation
A surgeon may place instrumentation in the spine as part of the fusion procedure. Report the appropriate add-on code based on approach and instrumentation:
- 22840–22844 (posterior instrumentation)
- 22845–22847 (anterior instrumentation)
- 22848 (pelvic fixation)
Surgeons may use a biomechanical device, such as:
- Polyether ether ketone (PEEK) devices (e.g., Mosaic, LDR, GraftCage, Capstone, Zero-P, STALIF, Solitaire)
- HARMS cage
- BAK cage
- Methylmethacrylate (i.e., bone cement)
Report the application of the above listed intervertebral biomechanical device(s) using add-on code 22851. Note that coders should report code 22851 per interspace or vertebral defect, not per device, says Pollock. Append modifier -59 (distinct procedural service) for each code that indicates an additional interspace.
Although polyether ether ketone (PEEK) does not really fit the definition of a biomechanical device, coders should report it using code 22851, Stumpf says. Report all structural allografts using code 20931, so they need to pay careful attention to what the device is made of in order to bill biomechanical devices correctly, says Stumpf.
Consider the type of bone graft
Allograft is bone obtained from a donor—not from the patient (i.e., autograft). An allograft bone contains no living cells. Think of an allograft as bone in a bottle or a package. Coders should report all bone graft codes only once per surgery with, Pollock says.
The bone graft codes include:
- 20930 (allograft or osteopromotive material for spine surgery, morselized)
- 20931 (allograft for spine surgery, structural)
- 20936 (autograft, local)
- 20937 (harvest of graft through separate skin incision, commonly iliac crest)
- 20938 (autograft, structural, bicortical, or tricortical)
Coders should only report each bone graft code performed only once per operative session.
Bear in mind other factors
Once coders locate the fusion, instrumentation, grafts, and decompression if the physician performed it, they need to look for some additional elements.
Look to see whether the surgeon used a microscope for microdissection or microsurgical techniques. But note that some carriers—Medicare and private payers who follow Medicare guidelines—will not pay for the use of a microscope, Stumpf says.
However, other private payers will. So for those cases, follow CPT guidelines for reporting the use of the microscope, which are completely different from the National Correct Coding Initiative (NCCI) edits, she says. CPT guidelines instruct coders to report the microscope use, and CPT lists specific codes with which it should not be reported. However, NCCI edits bundle the microscope into the procedure code.
To report use of the microscope, however, physicians must document that they used it for a microsurgical technique and not just for magnification or illumination, Pollock says.
Also remember that CPT guidelines do not prohibit coders from reporting the use of a microscope for a discectomy or laminectomy, Pollock adds. Coders should report the use of the microscope even when the payer won’t reimburse for it because it is an appropriate CPT combination.
Medicare also sometimes reverses the NCCI edits, Pollock adds. “If you didn’t bill for it originally, you won’t be able to file for a redetermination.”
When the surgeon uses a microscope for microdissection, report CPT add-on code 69990 (use of operating microscope) separately in addition to the code for the primary procedure.
When coding for the microscope used for microdissection or microsurgical techniques, coders need to see documentation of the work involved in bringing the microscope into the field, leaving the field, and during the procedure, Stumpf says. The same holds true for the use of stereotactic navigation. The provider needs to set up, use, and document the use of the instrumentation to support the coding.
E-mail your questions to Senior Managing Editor Michelle A. Leppert, CPC-A, at email@example.com.
Interested in learning more about spinal coding? Shelley C. Safian, PhD, MAOM/HSM, CCS-P, CPC-H, CPC-I, CHA, AHIMA-approved ICD-10-CM/PCS trainer of Safian Communications Services and Kristi Stumpf, MCS-P, CPC, COSC, ACS-OR, senior orthopedic coder and auditor for the The Coding Network based in Beverly Hills, CA, discuss ICD-9-CM and CPT coding for spinal procedures during HCPro’s July 28 audio conference, “Spinal ICD-9 and CPT Coding: Get the Complete Picture for Accurate Reimbursement”. To learn more or to purchase, go to the HCMarketplace Web site. | <urn:uuid:8e16b5c9-0d73-418b-b770-720701f08541> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422121899763.95/warc/CC-MAIN-20150124175139-00167-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 3,
"language": "en",
"language_score": 0.8662746548652649,
"score": 2.65625,
"token_count": 1967,
"url": "http://www.justcoding.com/270546/get-the-facts-on-spinal-fusion-instrumentation-and-grafts"
} |
|Classification and external resources|
Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen (O
2) at elevated partial pressures. It is also known as oxygen toxicity syndrome, oxygen intoxication, and oxygen poisoning. Historically, the central nervous system condition was called the Paul Bert effect, and the pulmonary condition the Lorrain Smith effect, after the researchers who pioneered its discovery and description in the late 19th century. Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lungs and eyes. Oxygen toxicity is a concern for underwater divers, those on high concentrations of supplemental oxygen (particularly premature babies), and those undergoing hyperbaric oxygen therapy.
The result of breathing elevated partial pressures of oxygen is hyperoxia, an excess of oxygen in body tissues. The body is affected in different ways depending on the type of exposure. Central nervous system toxicity is caused by short exposure to high partial pressures of oxygen at greater than atmospheric pressure. Pulmonary and ocular toxicity result from longer exposure to elevated oxygen levels at normal pressure. Symptoms may include disorientation, breathing problems, and vision changes such as myopia. Prolonged exposure to above-normal oxygen partial pressures, or shorter exposures to very high partial pressures, can cause oxidative damage to cell membranes, the collapse of the alveoli in the lungs, retinal detachment, and seizures. Oxygen toxicity is managed by reducing the exposure to elevated oxygen levels. Studies show that, in the long term, a robust recovery from most types of oxygen toxicity is possible.
Protocols for avoidance of hyperoxia exist in fields where oxygen is breathed at higher-than-normal partial pressures, including underwater diving using compressed breathing gases, hyperbaric medicine, neonatal care and human spaceflight. These protocols have resulted in the increasing rarity of seizures due to oxygen toxicity, with pulmonary and ocular damage being mainly confined to the problems of managing premature infants.
In recent years, oxygen has become available for recreational use in oxygen bars. The US Food and Drug Administration has warned those suffering from problems such as heart or lung disease not to use oxygen bars. Scuba divers use breathing gases containing up to 100% oxygen, and should have specific training in using such gases.
- 1 Classification
- 2 Signs and symptoms
- 3 Causes
- 4 Mechanism
- 5 Diagnosis
- 6 Prevention
- 7 Management
- 8 Prognosis
- 9 Epidemiology
- 10 History
- 11 Society and culture
- 12 See also
- 13 References
- 14 Sources
- 15 Further reading
- 16 External links
- Central nervous system, characterised by convulsions followed by unconsciousness, occurring under hyperbaric conditions;
- Pulmonary (lungs), characterised by difficulty in breathing and pain within the chest, occurring when breathing elevated pressures of oxygen for extended periods;
- Ocular (retinopathic conditions), characterised by alterations to the eyes, occurring when breathing elevated pressures of oxygen for extended periods.
Central nervous system oxygen toxicity can cause seizures, brief periods of rigidity followed by convulsions and unconsciousness, and is of concern to divers who encounter greater than atmospheric pressures. Pulmonary oxygen toxicity results in damage to the lungs, causing pain and difficulty in breathing. Oxidative damage to the eye may lead to myopia or partial detachment of the retina. Pulmonary and ocular damage are most likely to occur when supplemental oxygen is administered as part of a treatment, particularly to newborn infants, but are also a concern during hyperbaric oxygen therapy.
Oxidative damage may occur in any cell in the body but the effects on the three most susceptible organs will be the primary concern. It may also be implicated in red blood cell destruction (haemolysis), damage to liver (hepatic), heart (myocardial), endocrine glands (adrenal, gonads, and thyroid), or kidneys (renal), and general damage to cells.
In unusual circumstances, effects on other tissues may be observed: it is suspected that during spaceflight, high oxygen concentrations may contribute to bone damage. Hyperoxia can also indirectly cause carbon dioxide narcosis in patients with lung ailments such as chronic obstructive pulmonary disease or with central respiratory depression. Hyperventilation of atmospheric air at atmospheric pressures does not cause oxygen toxicity, because sea-level air a has a partial pressure of oxygen (ppO
2) of 0.21 bar (21 kPa) and the lower limit for toxicity is more than 0.3 bar (30 kPa).
Signs and symptoms
|Exposure (mins.)||Num. of Subjects||Symptoms|
|96||1||Prolonged dazzle; severe spasmodic vomiting|
|60–69||3||Severe lip-twitching; Euphoria; Nausea and vertigo; arm twitch|
|50–55||4||Severe lip-twitching; Dazzle; Blubbering of lips; fell asleep; Dazed|
|31–35||4||Nausea, vertigo, lip-twitching; Convulsed|
|21–30||6||Convulsed; Drowsiness; Severe lip-twitching; epigastric aura; twitch L arm; amnesia|
|16–20||8||Convulsed; Vertigo and severe lip twitching; epigastric aura; spasmodic respiration;|
|11–15||4||Inspiratory predominance; lip-twitching and syncope; Nausea and confusion|
|6–10||6||Dazed and lip-twitching; paraesthesiae; vertigo; "Diaphragmatic spasm"; Severe nausea|
Central nervous system
Central nervous system oxygen toxicity manifests as symptoms such as visual changes (especially tunnel vision), ringing in the ears (tinnitus), nausea, twitching (especially of the face), irritability (personality changes, anxiety, confusion, etc.), and dizziness. This may be followed by a tonic–clonic seizure consisting of two phases: intense muscle contraction occurs for several seconds (tonic); followed by rapid spasms of alternate muscle relaxation and contraction producing convulsive jerking (clonic). The seizure ends with a period of unconsciousness (the postictal state). The onset of seizure depends upon the partial pressure of oxygen (ppO
2) in the breathing gas and exposure duration. However, exposure time before onset is unpredictable, as tests have shown a wide variation, both amongst individuals, and in the same individual from day to day. In addition, many external factors, such as underwater immersion, exposure to cold, and exercise will decrease the time to onset of central nervous system symptoms. Decrease of tolerance is closely linked to retention of carbon dioxide. Other factors, such as darkness and caffeine, increase tolerance in test animals, but these effects have not been proven in humans.
Pulmonary toxicity symptoms result from an inflammation that starts in the airways leading to the lungs and then spreads into the lungs (tracheobronchial tree). The symptoms appear in the upper chest region (substernal and carinal regions). This begins as a mild tickle on inhalation and progresses to frequent coughing. If breathing elevated partial pressures of oxygen is not discontinued, patients experience a mild burning on inhalation along with uncontrollable coughing and occasional shortness of breath (dyspnoea). Physical findings related to pulmonary toxicity have included bubbling sounds heard through a stethoscope (bubbling rales), fever, and increased blood flow to the lining of the nose (hyperaemia of the nasal mucosa). The radiological finding from the lungs shows inflammation and swelling (pulmonary oedema). Pulmonary function measurements are reduced, as noted by a reduction in the amount of air that the lungs can hold (vital capacity) and changes in expiratory function and lung elasticity. Tests in animals have indicated a variation in tolerance similar to that found in central nervous system toxicity, as well as significant variations between species. When the exposure to oxygen above 0.5 bar (50 kPa) is intermittent, it permits the lungs to recover and delays the onset of toxicity.
In premature babies, signs of damage to the eye (retinopathy of prematurity, or ROP) are observed via an ophthalmoscope as a demarcation between the vascularised and non-vascularised regions of an infant's retina. The degree of this demarcation is used to designate four stages: (I) the demarcation is a line; (II) the demarcation becomes a ridge; (III) growth of new blood vessels occurs around the ridge; (IV) the retina begins to detach from the inner wall of the eye (choroid).
Oxygen toxicity is caused by exposure to oxygen at partial pressures greater than those to which the body is normally exposed. This occurs in three principal settings: underwater diving, hyperbaric oxygen therapy, and the provision of supplemental oxygen, particularly to premature infants. In each case, the risk factors are markedly different.
Central nervous system toxicity
Exposures, from minutes to a few hours, to partial pressures of oxygen above 1.6 bars (160 kPa)—about eight times the standard atmospheric partial pressure—are usually associated with central nervous system oxygen toxicity and are most likely to occur among patients undergoing hyperbaric oxygen therapy and divers. Since sea level atmospheric pressure is about 1 bar (100 kPa), central nervous system toxicity can only occur under hyperbaric conditions, where ambient pressure is above normal. Divers breathing air at depths greater than 60 m (200 ft) face an increasing risk of an oxygen toxicity "hit" (seizure). Divers breathing a gas mixture enriched with oxygen, such as nitrox, can similarly suffer a seizure at shallower depths, should they descend below the maximum operating depth allowed for the mixture.
The lungs, as well as the remainder of the respiratory tract, are exposed to the highest concentration of oxygen in the human body and are therefore the first organs to show toxicity. Pulmonary toxicity occurs with exposure to partial pressures of oxygen greater than 0.5 bar (50 kPa), corresponding to an oxygen fraction of 50% at normal atmospheric pressure. Signs of pulmonary toxicity begins with evidence of tracheobronchitis, or inflammation of the upper airways, after an asymptomatic period between 4 and 22 hours at greater than 95% oxygen, with some studies suggesting symptoms usually begin after approximately 14 hours at this level of oxygen.
At partial pressures of oxygen of 2 to 3 bar (200 to 300 kPa)—100% oxygen at 2 to 3 times atmospheric pressure—these symptoms may begin as early as 3 hours after exposure to oxygen. Experiments on rats breathing oxygen at pressures between 1 and 3 bars (100 and 300 kPa) show that pulmonary manifestations of oxygen toxicity are not the same for normobaric conditions as they are for hyperbaric conditions. Evidence of decline in lung function as measured by pulmonary function testing can occur as quickly as 24 hours of continuous exposure to 100% oxygen, with evidence of diffuse alveolar damage and the onset of acute respiratory distress syndrome usually occurring after 48 hours on 100% oxygen. Breathing 100% oxygen also eventually leads to collapse of the alveoli (atelectasis), while—at the same partial pressure of oxygen—the presence of significant partial pressures of inert gases, typically nitrogen, will prevent this effect.
Preterm newborns are known to be at higher risk for bronchopulmonary dysplasia with extended exposure to high concentrations of oxygen. Other groups at higher risk for oxygen toxicity are patients on mechanical ventilation with exposure to levels of oxygen greater than 50%, and patients exposed to chemicals that increase risk for oxygen toxicity such the chemotherapeutic agent bleomycin. Therefore, current guidelines for patients on mechanical ventilation in intensive care recommends keeping oxygen concentration less than 60%. Likewise, divers who undergo treatment of decompression sickness are at increased risk of oxygen toxicity as treatment entails exposure to long periods of oxygen breathing under hyperbaric conditions, in addition to any oxygen exposure during the dive.
Prolonged exposure to high inspired fractions of oxygen causes damage to the retina. Damage to the developing eye of infants exposed to high oxygen fraction at normal pressure has a different mechanism and effect from the eye damage experienced by adult divers under hyperbaric conditions. Hyperoxia may be a contributing factor for the disorder called retrolental fibroplasia or retinopathy of prematurity (ROP) in infants. In preterm infants, the retina is often not fully vascularised. Retinopathy of prematurity occurs when the development of the retinal vasculature is arrested and then proceeds abnormally. Associated with the growth of these new vessels is fibrous tissue (scar tissue) that may contract to cause retinal detachment. Supplemental oxygen exposure, while a risk factor, is not the main risk factor for development of this disease. Restricting supplemental oxygen use does not necessarily reduce the rate of retinopathy of prematurity, and may raise the risk of hypoxia-related systemic complications.
Hyperoxic myopia has occurred in closed circuit oxygen rebreather divers with prolonged exposures. It also occurs frequently in those undergoing repeated hyperbaric oxygen therapy. This is due to an increase in the refractive power of the lens, since axial length and keratometry readings do not reveal a corneal or length basis for a myopic shift. It is usually reversible with time.
The biochemical basis for the toxicity of oxygen is the partial reduction of oxygen by one or two electrons to form reactive oxygen species, which are natural by-products of the normal metabolism of oxygen and have important roles in cell signalling. One species produced by the body, the superoxide anion (O
2–), is possibly involved in iron acquisition. Higher than normal concentrations of oxygen lead to increased levels of reactive oxygen species. Oxygen is necessary for cell metabolism, and the blood supplies it to all parts of the body. When oxygen is breathed at high partial pressures, a hyperoxic condition will rapidly spread, with the most vascularised tissues being most vulnerable. During times of environmental stress, levels of reactive oxygen species can increase dramatically, which can damage cell structures and produce oxidative stress.
While all the reaction mechanisms of these species within the body are not yet fully understood, one of the most reactive products of oxidative stress is the hydroxyl radical (·OH), which can initiate a damaging chain reaction of lipid peroxidation in the unsaturated lipids within cell membranes. High concentrations of oxygen also increase the formation of other free radicals, such as nitric oxide, peroxynitrite, and trioxidane, which harm DNA and other biomolecules. Although the body has many antioxidant systems such as glutathione that guard against oxidative stress, these systems are eventually overwhelmed at very high concentrations of free oxygen, and the rate of cell damage exceeds the capacity of the systems that prevent or repair it. Cell damage and cell death then result.
Diagnosis of central nervous system oxygen toxicity in divers prior to seizure is difficult as the symptoms of visual disturbance, ear problems, dizziness, confusion and nausea can be due to many factors common to the underwater environment such as narcosis, congestion and coldness. However, these symptoms may be helpful in diagnosing the first stages of oxygen toxicity in patients undergoing hyperbaric oxygen therapy. In either case, unless there is a prior history of epilepsy or tests indicate hypoglycaemia, a seizure occurring in the setting of breathing oxygen at partial pressures greater than 1.4 bar (140 kPa) suggests a diagnosis of oxygen toxicity.
Diagnosis of bronchopulmonary dysplasia in newborn infants with breathing difficulties is difficult in the first few weeks. However, if the infant's breathing does not improve during this time, blood tests and x-rays may be used to confirm bronchopulmonary dysplasia. In addition, an echocardiogram can help to eliminate other possible causes such as congenital heart defects or pulmonary arterial hypertension.
The diagnosis of retinopathy of prematurity in infants is typically suggested by the clinical setting. Prematurity, low birth weight and a history of oxygen exposure are the principal indicators, while no hereditary factors have been shown to yield a pattern.
The prevention of oxygen toxicity depends entirely on the setting. Both underwater and in space, proper precautions can eliminate the most pernicious effects. Premature infants commonly require supplemental oxygen to treat complications of preterm birth. In this case prevention of bronchopulmonary dysplasia and retinopathy of prematurity must be carried out without compromising a supply of oxygen adequate to preserve the infant's life.
Oxygen toxicity is a catastrophic hazard in diving, because a seizure results in near certain death by drowning. The seizure may occur suddenly and with no warning symptoms. The effects are sudden convulsions and unconsciousness, during which victims can lose their regulator and drown. One of the advantages of a full-face diving mask is prevention of regulator loss in the event of a seizure. As there is an increased risk of central nervous system oxygen toxicity on deep dives, long dives and dives where oxygen-rich breathing gases are used, divers are taught to calculate a maximum operating depth for oxygen-rich breathing gases, and cylinders containing such mixtures must be clearly marked with that depth.
In some diver training courses for these types of diving, divers are taught to plan and monitor what is called the oxygen clock of their dives. This is a notional alarm clock, which ticks more quickly at increased ppO
2 and is set to activate at the maximum single exposure limit recommended in the National Oceanic and Atmospheric Administration Diving Manual. For the following partial pressures of oxygen the limit is: 45 minutes at 1.6 bar (160 kPa), 120 minutes at 1.5 bar (150 kPa), 150 minutes at 1.4 bar (140 kPa), 180 minutes at 1.3 bar (130 kPa) and 210 minutes at 1.2 bar (120 kPa), but is impossible to predict with any reliability whether or when toxicity symptoms will occur. Many nitrox-capable dive computers calculate an oxygen loading and can track it across multiple dives. The aim is to avoid activating the alarm by reducing the ppO
2 of the breathing gas or the length of time breathing gas of higher ppO
2. As the ppO
2 depends on the fraction of oxygen in the breathing gas and the depth of the dive, the diver obtains more time on the oxygen clock by diving at a shallower depth, by breathing a less oxygen-rich gas, or by shortening the duration of exposure to oxygen-rich gases.
Diving below 56 m (184 ft) on air would expose a diver to increasing danger of oxygen toxicity as the partial pressure of oxygen exceeds 1.4 bar (140 kPa), so a gas mixture must be used which contains less than 21% oxygen (a hypoxic mixture). Increasing the proportion of nitrogen is not viable, since it would produce a strongly narcotic mixture. However, helium is not narcotic, and a usable mixture may be blended either by completely replacing nitrogen with helium (the resulting mix is called heliox), or by replacing part of the nitrogen with helium, producing a trimix.
Pulmonary oxygen toxicity is an entirely avoidable event while diving. The limited duration and naturally intermittent nature of most diving makes this a relatively rare (and even then, reversible) complication for divers. Guidelines have been established that allow divers to calculate when they are at risk of pulmonary toxicity.
The presence of a fever or a history of seizure is a relative contraindication to hyperbaric oxygen treatment. The schedules used for treatment of decompression illness allow for periods of breathing air rather than 100% oxygen (oxygen breaks) to reduce the chance of seizure or lung damage. The U.S. Navy uses treatment tables based on periods alternating between 100% oxygen and air. For example, USN table 6 requires 75 minutes (three periods of 20 minutes oxygen/5 minutes air) at an ambient pressure of 2.8 standard atmospheres (280 kPa), equivalent to a depth of 18 metres (60 ft). This is followed by a slow reduction in pressure to 1.9 atm (190 kPa) over 30 minutes on oxygen. The patient then remains at that pressure for a further 150 minutes, consisting of two periods of 15 minutes air/60 minutes oxygen, before the pressure is reduced to atmospheric over 30 minutes on oxygen.
Vitamin E and selenium were proposed and later rejected as a potential method of protection against pulmonary oxygen toxicity. There is however some experimental evidence in rats that vitamin E and selenium aid in preventing in vivo lipid peroxidation and free radical damage, and therefore prevent retinal changes following repetitive hyperbaric oxygen exposures.
Bronchopulmonary dysplasia is reversible in the early stages by use of break periods on lower pressures of oxygen, but it may eventually result in irreversible lung injury if allowed to progress to severe damage. One or two days of exposure without oxygen breaks are needed to cause such damage.
Retinopathy of prematurity is largely preventable by screening. Current guidelines require that all babies of less than 32 weeks gestational age or having a birth weight less than 1.5 kg (3.3 lb) should be screened for retinopathy of prematurity at least every two weeks. The National Cooperative Study in 1954 showed a causal link between supplemental oxygen and retinopathy of prematurity, but subsequent curtailment of supplemental oxygen caused an increase in infant mortality. To balance the risks of hypoxia and retinopathy of prematurity, modern protocols now require monitoring of blood oxygen levels in premature infants receiving oxygen.
In low-pressure environments oxygen toxicity may be avoided since the toxicity is caused by high partial pressure of oxygen, not merely by high oxygen fraction. This is illustrated by modern pure oxygen use in spacesuits, which must operate at low pressure (also historically, very high percentage oxygen and lower than normal atmospheric pressure was used in early spacecraft, for example, the Gemini and Apollo spacecraft). In such applications as extra-vehicular activity, high-fraction oxygen is non-toxic, even at breathing mixture fractions approaching 100%, because the oxygen partial pressure is not allowed to chronically exceed 0.3 bar (4.4 psi).
During hyperbaric oxygen therapy, the patient will usually breathe 100% oxygen from a mask while inside a hyperbaric chamber pressurised with air to about 2.8 bar (280 kPa). Seizures during the therapy are managed by removing the mask from the patient, thereby dropping the partial pressure of oxygen inspired below 0.6 bar (60 kPa).
A seizure underwater requires that the diver be brought to the surface as soon as practicable. Although for many years the recommendation has been not to raise the diver during the seizure itself, owing to the danger of arterial gas embolism (AGE), there is some evidence that the glottis does not fully obstruct the airway. This has led to the current recommendation by the Diving Committee of the Undersea and Hyperbaric Medical Society that a diver should be raised during the seizure's clonic (convulsive) phase if the regulator is not in the diver's mouth – as the danger of drowning is then greater than that of AGE – but the ascent should be delayed until the end of the clonic phase otherwise. Rescuers ensure that their own safety is not compromised during the convulsive phase. They then ensure that where the victim's air supply is established it is maintained, and carry out a controlled buoyant lift. Lifting an unconscious body is taught by most diver training agencies. Upon reaching the surface, emergency services are always contacted as there is a possibility of further complications requiring medical attention. The U.S. Navy has procedures for completing the decompression stops where a recompression chamber is not immediately available.
The occurrence of symptoms of bronchopulmonary dysplasia or acute respiratory distress syndrome is treated by lowering the fraction of oxygen administered, along with a reduction in the periods of exposure and an increase in the break periods where normal air is supplied. Where supplemental oxygen is required for treatment of another disease (particularly in infants), a ventilator may be needed to ensure that the lung tissue remains inflated. Reductions in pressure and exposure will be made progressively, and medications such as bronchodilators and pulmonary surfactants may be used.
Retinopathy of prematurity may regress spontaneously, but should the disease progress beyond a threshold (defined as five contiguous or eight cumulative hours of stage 3 retinopathy of prematurity), both cryosurgery and laser surgery have been shown to reduce the risk of blindness as an outcome. Where the disease has progressed further, techniques such as scleral buckling and vitrectomy surgery may assist in re-attaching the retina.
Although the convulsions caused by central nervous system oxygen toxicity may lead to incidental injury to the victim, it remained uncertain for many years whether damage to the nervous system following the seizure could occur and several studies searched for evidence of such damage. An overview of these studies by Bitterman in 2004 concluded that following removal of breathing gas containing high fractions of oxygen, no long-term neurological damage from the seizure remains.
The majority of infants who have survived following an incidence of bronchopulmonary dysplasia will eventually recover near-normal lung function, since lungs continue to grow during the first 5–7 years and the damage caused by bronchopulmonary dysplasia is to some extent reversible (even in adults). However, they are likely be more susceptible to respiratory infections for the rest of their lives and the severity of later infections is often greater than that in their peers.
Retinopathy of prematurity (ROP) in infants frequently regresses without intervention and eyesight may be normal in later years. Where the disease has progressed to the stages requiring surgery, the outcomes are generally good for the treatment of stage 3 ROP, but are much worse for the later stages. Although surgery is usually successful in restoring the anatomy of the eye, damage to the nervous system by the progression of the disease leads to comparatively poorer results in restoring vision. The presence of other complicating diseases also reduces the likelihood of a favourable outcome.
The incidence of central nervous system toxicity among divers has decreased since the Second World War, as protocols have developed to limit exposure and partial pressure of oxygen inspired. In 1947, Donald recommended limiting the depth allowed for breathing pure oxygen to 7.6 m (25 ft), or a ppO
2 of 1.8 bar (180 kPa). This limit has been reduced, until today a limit of 1.4 bar (140 kPa) during a recreational dive and 1.6 bar (160 kPa) during shallow decompression stops is accepted. Oxygen toxicity has now become a rare occurrence other than when caused by equipment malfunction and human error. Historically, the U.S. Navy has refined its Navy Diving Manual Tables to reduce oxygen toxicity incidents. Between 1995 and 1999, reports showed 405 surface-supported dives using the helium–oxygen tables; of these, oxygen toxicity symptoms were observed on 6 dives (1.5%). As a result, the U.S. Navy in 2000 modified the schedules and conducted field tests of 150 dives, none of which produced symptoms of oxygen toxicity. Revised tables were published in 2001.
The variability in tolerance and other variable factors such as workload have resulted in the U.S. Navy abandoning screening for oxygen tolerance. Of the 6,250 oxygen-tolerance tests performed between 1976 and 1997, only 6 episodes of oxygen toxicity were observed (0.1%).
Central nervous system oxygen toxicity among patients undergoing hyperbaric oxygen therapy is rare, and is influenced by a number of a factors: individual sensitivity and treatment protocol; and probably therapy indication and equipment used. A study by Welslau in 1996 reported 16 incidents out of a population of 107,264 patients (0.015%), while Hampson and Atik in 2003 found a rate of 0.03%. Yildiz, Ay and Qyrdedi, in a summary of 36,500 patient treatments between 1996 and 2003, reported only 3 oxygen toxicity incidents, giving a rate of 0.008%. A later review of over 80,000 patient treatments revealed an even lower rate: 0.0024%. The reduction in incidence may be partly due to use of a mask (rather than a hood) to deliver oxygen.
Bronchopulmonary dysplasia is among the most common complications of prematurely born infants and its incidence has grown as the survival of extremely premature infants has increased. Nevertheless, the severity has decreased as better management of supplemental oxygen has resulted in the disease now being related mainly to factors other than hyperoxia.
In 1997 a summary of studies of neonatal intensive care units in industrialised countries showed that up to 60% of low birth weight babies developed retinopathy of prematurity, which rose to 72% in extremely low birth weight babies, defined as less than 1 kg (2.2 lb) at birth. However, severe outcomes are much less frequent: for very low birth weight babies—those less than 1.5 kg (3.3 lb) at birth—the incidence of blindness was found to be no more than 8%.
Central nervous system toxicity was first described by Paul Bert in 1878. He showed that oxygen was toxic to insects, arachnids, myriapods, molluscs, earthworms, fungi, germinating seeds, birds, and other animals. Central nervous system toxicity may be referred to as the "Paul Bert effect".
Pulmonary oxygen toxicity was first described by J. Lorrain Smith in 1899 when he noted central nervous system toxicity and discovered in experiments in mice and birds that 0.43 bar (43 kPa) had no effect but 0.75 bar (75 kPa) of oxygen was a pulmonary irritant. Pulmonary toxicity may be referred to as the "Lorrain Smith effect". The first recorded human exposure was undertaken in 1910 by Bornstein when two men breathed oxygen at 2.8 bar (280 kPa) for 30 minutes while he went on to 48 minutes with no symptoms. In 1912, Bornstein developed cramps in his hands and legs while breathing oxygen at 2.8 bar (280 kPa) for 51 minutes. Smith then went on to show that intermittent exposure to a breathing gas with less oxygen permitted the lungs to recover and delayed the onset of pulmonary toxicity.
Albert R. Behnke et al. in 1935 were the first to observe visual field contraction (tunnel vision) on dives between 1.0 bar (100 kPa) and 4.1 bar (410 kPa). During World War II, Donald and Yarbrough et al. performed over 2,000 experiments on oxygen toxicity to support the initial use of closed circuit oxygen rebreathers. Naval divers in the early years of oxygen rebreather diving developed a mythology about a monster called "Oxygen Pete", who lurked in the bottom of the Admiralty Experimental Diving Unit "wet pot" (a water-filled hyperbaric chamber) to catch unwary divers. They called having an oxygen toxicity attack "getting a Pete".
In the decade following World War II, Lambertsen et al. made further discoveries on the effects of breathing oxygen under pressure as well as methods of prevention. Their work on intermittent exposures for extension of oxygen tolerance and on a model for prediction of pulmonary oxygen toxicity based on pulmonary function are key documents in the development of standard operating procedures when breathing elevated pressures of oxygen. Lambertsen's work showing the effect of carbon dioxide in decreasing time to onset of central nervous system symptoms has influenced work from current exposure guidelines to future breathing apparatus design.
Retinopathy of prematurity was not observed prior to World War II, but with the availability of supplemental oxygen in the decade following, it rapidly became one of the principal causes of infant blindness in developed countries. By 1960 the use of oxygen had become identified as a risk factor and its administration restricted. The resulting fall in retinopathy of prematurity was accompanied by a rise in infant mortality and hypoxia-related complications. Since then, more sophisticated monitoring and diagnosis have established protocols for oxygen use which aim to balance between hypoxic conditions and problems of retinopathy of prematurity.
Bronchopulmonary dysplasia was first described by Northway in 1967, who outlined the conditions that would lead to the diagnosis. This was later expanded by Bancalari and in 1988 by Shennan, who suggested the need for supplemental oxygen at 36 weeks could predict long-term outcomes. Nevertheless, Palta et al. in 1998 concluded that radiographic evidence was the most accurate predictor of long-term effects.
Bitterman et al. in 1986 and 1995 showed that darkness and caffeine would delay the onset of changes to brain electrical activity in rats. In the years since, research on central nervous system toxicity has centred on methods of prevention and safe extension of tolerance. Sensitivity to central nervous system oxygen toxicity has been shown to be affected by factors such as circadian rhythm, drugs, age, and gender. In 1988, Hamilton et al. wrote procedures for the National Oceanic and Atmospheric Administration to establish oxygen exposure limits for habitat operations. Even today, models for the prediction of pulmonary oxygen toxicity do not explain all the results of exposure to high partial pressures of oxygen.
Society and culture
Recreational scuba divers commonly breathe nitrox containing up to 40% oxygen, while technical divers use pure oxygen or nitrox containing up to 80% oxygen. Divers who breathe oxygen fractions greater than of air (21%) need to be trained in the dangers of oxygen toxicity and how to prevent them. In order to buy nitrox, a diver has to show evidence of such qualification.
Since the late 1990s the recreational use of oxygen has been promoted by oxygen bars, where customers breathe oxygen through a nasal cannula. Claims have been made that this reduces stress, increases energy, and lessens the effects of hangovers and headaches, despite the lack of any scientific evidence to support them. There are also devices on sale that offer "oxygen massage" and "oxygen detoxification" with claims of removing body toxins and reducing body fat. The American Lung Association has stated "there is no evidence that oxygen at the low flow levels used in bars can be dangerous to a normal person's health", but the U.S. Center for Drug Evaluation and Research cautions that people with heart or lung disease need their supplementary oxygen carefully regulated and should not use oxygen bars.
Victorian society had a fascination for the rapidly expanding field of science. In "Dr. Ox's Experiment", a short story written by Jules Verne in 1872, the eponymous doctor uses electrolysis of water to separate oxygen and hydrogen. He then pumps the pure oxygen throughout the town of Quiquendone, causing the normally tranquil inhabitants and their animals to become aggressive and plants to grow rapidly. An explosion of the hydrogen and oxygen in Dr Ox's factory brings his experiment to an end. Verne summarised his story by explaining that the effects of oxygen described in the tale were his own invention. There is also a brief episode of oxygen intoxication in his "From the Earth to the Moon".
- Donald, Part I 1947.
- Clark & Thom 2003, pp. 358–360.
- Acott, Chris (1999). "Oxygen toxicity: A brief history of oxygen in diving". South Pacific Underwater Medicine Society Journal 29 (3): 150–5. ISSN 0813-1988. OCLC 16986801. Retrieved 29 April 2008.
- Beehler, CC (1964). "Oxygen and the eye". Survey of Ophthalmology 45: 549–60. PMID 14232720.
- Goldstein, JR; Mengel, CE (1969). "Hemolysis in mice exposed to varying levels of hyperoxia". Aerospace Medicine 40 (1): 12–13. PMID 5782651.
- Larkin, EC; Adams, JD; Williams, WT; Duncan, DM (1972). "Hematologic responses to hypobaric hyperoxia". American Journal of Physiology 223 (2): 431–7. PMID 4403030.
- Schaffner, Fenton; Felig, Philip (1965). "CHANGES IN HEPATIC STRUCTURE IN RATS PRODUCED BY BREATHING PURE OXYGEN" (PDF). Journal of Cell Biology 27 (3): 505–17. doi:10.1083/jcb.27.3.505. PMC 2106769. PMID 5885427.
- Caulfield, JB; Shelton, RW; Burke, JF (1972). "Cytotoxic effects of oxygen on striated muscle". Archives of Pathology 94 (2): 127–32. PMID 5046798.
- Bean, JW; Johnson, PC (1954). "Adrenocortical response to single and repeated exposure to oxygen at high pressure". American Journal of Physiology 179 (3): 410–4. PMID 13228600.
- Edstrom, JE; Rockert, H (1962). "The effect of oxygen at high pressure on the histology of the central nervous system and sympathetic and endocrine cells". Acta Physiologica Scandinavica 55 (2–3): 255–63. doi:10.1111/j.1748-1716.1962.tb02438.x. PMID 13889254.
- Gersh, I; Wagner, CE (1945). "Metabolic factors in oxygen poisoning". American Journal of Physiology 144 (2): 270–7.
- Hess, RT; Menzel, DB (1971). "Effect of dietary antioxidant level and oxygen exposure on the fine structure of the proximal convoluted tubules". Aerospace Medicine 42 (6): 646–9. PMID 5155150.
- Clark, John M (1974). "The toxicity of oxygen". American Review of Respiratory Disease 110 (6 Pt 2): 40–50. PMID 4613232.
- Patel, Dharmeshkumar N; Goel, Ashish; Agarwal, SB; Garg, Praveenkumar; Lakhani, Krishna K (2003). "Oxygen toxicity" (PDF). Journal, Indian Academy of Clinical Medicine 4 (3): 234–237. Retrieved 28 September 2008.
- Clark & Lambertsen 1970.
- Clark & Thom 2003, p. 376.
- Bitterman, N. (2004). "CNS oxygen toxicity". Undersea and Hyperbaric Medicine 31 (1): 63–72. PMID 15233161. Retrieved 29 April 2008.
- Lang 2001, p. 82.
- Richardson, Drew; Menduno, Michael; Shreeves, Karl (eds) (1996). "Proceedings of rebreather forum 2.0". Diving Science and Technology Workshop: 286. Retrieved 20 September 2008.
- Richardson, Drew; Shreeves, Karl (1996). "The PADI enriched air diver course and DSAT oxygen exposure limits". South Pacific Underwater Medicine Society Journal 26 (3). ISSN 0813-1988. OCLC 16986801. Retrieved 2 May 2008.
- Bitterman, N.; Melamed, Y.; Perlman, I. (1986). "CNS oxygen toxicity in the rat: role of ambient illumination". Undersea Biomedical Research 13 (1): 19–25. PMID 3705247. Retrieved 20 September 2008.
- Bitterman, N.; Schaal, S. (1995). "Caffeine attenuates CNS oxygen toxicity in rats". Brain Research 696 (1–2): 250–3. doi:10.1016/0006-8993(95)00820-G. PMID 8574677.
- Clark & Thom 2003, p. 383.
- Clark, John M.; Lambertsen, Christian J. (1971). "Pulmonary oxygen toxicity: a review". Pharmacological Reviews 23 (2): 37–133. PMID 4948324.
- Clark, John M.; Lambertsen, Christian J. (1971). "Rate of development of pulmonary O2 toxicity in man during O2 breathing at 2.0 Ata". Journal of Applied Physiology 30 (5): 739–52. PMID 4929472.
- Clark & Thom 2003, pp. 386–387.
- Smith, J.Lorrain (1899). "The pathological effects due to increase of oxygen tension in the air breathed" (PDF). Journal of Physiology (London: The Physiological Society and Blackwell Publishing) 24 (1): 19–35. PMC 1516623. PMID 16992479. Note: 1 atmosphere (atm) is 1.013 bars.
- Fielder, Alistair R. (1993). Fielder, Alistair R.; Best, Anthony; Bax, Martin C. O, ed. The Management of Visual Impairment in Childhood. London: Mac Keith Press : Distributed by Cambridge University Press. p. 33. ISBN 0-521-45150-7.
- Smerz, R.W. (2004). "Incidence of oxygen toxicity during the treatment of dysbarism". Undersea and Hyperbaric Medicine 31 (2): 199–202. PMID 15485081. Retrieved 30 April 2008.
- Hampson, Neal B.; Simonson, Steven G.; Kramer, C.C.; Piantadosi, Claude A. (1996). "Central nervous system oxygen toxicity during hyperbaric treatment of patients with carbon monoxide poisoning". Undersea and Hyperbaric Medicine 23 (4): 215–9. PMID 8989851. Retrieved 29 April 2008.
- Lang 2001, p. 7.
- Bitterman, H. (2009). "Bench-to-bedside review: Oxygen as a drug". Critical Care 13 (1): 205. doi:10.1186/cc7151. PMC 2688103. PMID 19291278.
- Jackson, R.M. (1985). "Pulmonary oxygen toxicity". Chest 88 (6): 900–905. doi:10.1378/chest.88.6.900. PMID 3905287.
- Demchenko, Ivan T.; Welty-Wolf, Karen E.; Allen, Barry W.; Piantadosi, Claude A. (2007). "Similar but not the same: normobaric and hyperbaric pulmonary oxygen toxicity, the role of nitric oxide". American Journal of Physiology – Lung Cellular and Molecular Physiology 293 (1): L229–38. doi:10.1152/ajplung.00450.2006. PMID 17416738.
- Wittner, M.; Rosenbaum, R.M. (1966). "Pathophysiology of pulmonary oxygen toxicity". Proceedings of the Third International Conference on Hyperbaric Medicine (NAS/NRC, 1404, Washington DC): 179–88. – and others as discussed by Clark & Lambertsen 1970, pp. 256–60.
- Bancalari, Eduardo; Claure, Nelson; Sosenko, Ilene R.S. (2003). "Bronchopulmonary dysplasia: changes in pathogenesis, epidemiology and definition". Seminars in Neonatology (London: Elsevier Science) 8 (1): 63–71. doi:10.1016/S1084-2756(02)00192-6. PMID 12667831.
- Yarbrough, O.D.; Welham, W.; Brinton, E.S.; Behnke, Alfred R. (1947). "Symptoms of Oxygen Poisoning and Limits of Tolerance at Rest and at Work". Nedu-47-01 (United States Navy Experimental Diving Unit Technical Report). Retrieved 29 April 2008.
- Anderson, B.; Farmer, Joseph C. (1978). "Hyperoxic myopia". Transactions of the American Ophthalmological Society 76: 116–24. PMC 1311617. PMID 754368.
- Ricci, B.; Lepore, D.; Iossa, M.; Santo, A.; D'Urso, M.; Maggiano, N. (1990). "Effect of light on oxygen-induced retinopathy in the rat model. Light and OIR in the rat". Documenta Ophthalmologica 74 (4): 287–301. doi:10.1007/BF00145813. PMID 1701697.
- Drack, A.V. (1998). "Preventing blindness in premature infants". New England Journal of Medicine 338 (22): 1620–1. doi:10.1056/NEJM199805283382210. PMID 9603802.
- Butler, Frank K.; White, E.; Twa, M. (1999). "Hyperoxic myopia in a closed-circuit mixed-gas scuba diver". Undersea and Hyperbaric Medicine 26 (1): 41–5. PMID 10353183. Retrieved 29 April 2009.
- Nichols, C.W.; Lambertsen Christian (1969). "Effects of high oxygen pressures on the eye". New England Journal of Medicine 281 (1): 25–30. doi:10.1056/NEJM196907032810106. PMID 4891642.
- Shykoff, Barbara E. (2005). "Repeated Six-Hour Dives 1.35 ATM Oxygen Partial Pressure". Nedu-Tr-05-20 (Panama City, FL, USA: US Naval Experimental Diving Unit Technical Report). Retrieved 19 September 2008.
- Shykoff, Barbara E. (2008). "Pulmonary effects of submerged oxygen breathing in resting divers: repeated exposures to 140 kPa". Undersea and Hyperbaric Medicine 35 (2): 131–43. PMID 18500077.
- Anderson Jr., B.; Shelton, D.L. (1987). "Axial length in hyperoxic myopia". In: Bove, Alfred A.; Bachrach, Arthur J.; Greenbaum, Leon (eds.) Ninth International Symposium of the UHMS (Undersea and Hyperbaric Medical Society): 607–11.
- Schaal, S.; Beiran, I.; Rubinstein, I.; Miller, B.; Dovrat, A. (2005). "Oxygen effect on ocular lens". Harefuah (in Hebrew) 144 (11): 777–780, 822. PMID 16358652.
- Clark & Thom 2003, p. 360.
- Rhee S.G. (2006). "Cell signaling. H2O2, a necessary evil for cell signaling". Science 312 (5782): 1882–1883. doi:10.1126/science.1130481. PMID 16809515.
- Thom, Steven R. (1992). "Inert gas enhancement of superoxide radical production". Archives of Biochemistry and Biophysics 295 (2): 391–6. doi:10.1016/0003-9861(92)90532-2. PMID 1316738.
- Ghio, Andrew J.; Nozik-Grayck, Eva; Turi, Jennifer; Jaspers, Ilona; Mercatante, Danielle R.; Kole, Ryszard; Piantadosi, Claude A. (2003). "Superoxide-dependent iron uptake: a new role for anion exchange protein 2". American Journal of Respiratory Cell and Molecular Biology 29 (6): 653–60. doi:10.1165/rcmb.2003-0070OC. PMID 12791678.
- Fridovich, I. (1998). "Oxygen toxicity: a radical explanation" (PDF). Journal of Experimental Biology 201 (8): 1203–9. PMID 9510531.
- Piantadosi, Claude A. (2008). "Carbon Monoxide, Reactive Oxygen Signaling, and Oxidative Stress". Free Radical Biology & Medicine 45 (5): 562–9. doi:10.1016/j.freeradbiomed.2008.05.013. PMC 2570053. PMID 18549826.
- Imlay, J.A. (2003). "Pathways of oxidative damage". Annual Review of Microbiology 57: 395–418. doi:10.1146/annurev.micro.57.030502.090938. PMID 14527285.
- Bowen, R. "Free Radicals and Reactive Oxygen". Colorado State University. Retrieved 26 September 2008.
- Oury, T.D.; Ho, Y.S.; Piantadosi, Claude A.; Crapo, J.D. (1992). "Extracellular superoxide dismutase, nitric oxide, and central nervous system O2 toxicity" (PDF). Proceedings of the National Academy of Sciences of the United States of America 89 (20): 9715–9. Bibcode:1992PNAS...89.9715O. doi:10.1073/pnas.89.20.9715. PMC 50203. PMID 1329105.
- Thom, Steven R.; Marquis, R.E. (1987). "Free radical reactions and the inhibitory and lethal actions of high-pressure gases". Undersea Biomedical Research 14 (6): 485–501. PMID 2825395. Retrieved 26 September 2008.
- Djurhuus, R.; Svardal, A.M.; Thorsen, E. (1999). "Glutathione in the cellular defense of human lung cells exposed to hyperoxia and high pressure". Undersea and Hyperbaric Medicine 26 (2): 75–85. PMID 10372426. Retrieved 26 September 2008.
- Freiberger, John J.; Coulombe, Kathy; Suliman, Hagir; Carraway, Martha-sue; Piantadosi, Claude A. (2004). "Superoxide dismutase responds to hyperoxia in rat hippocampus". Undersea and Hyperbaric Medicine 31 (2): 227–32. PMID 15485085. Retrieved 26 September 2008.
- Kim, Y.S.; Kim, S.U. (1991). "Oligodendroglial cell death induced by oxygen radicals and its protection by catalase". Journal of Neuroscience Research 29 (1): 100–6. doi:10.1002/jnr.490290111. PMID 1886163.
- NBDHMT (4 February 2009). "Recommended Guidelines for Clinical Internship in Hyperbaric Technology (V: C.D)". Harvey, LA: National Board of Diving and Hyperbaric Medical Technology. Archived from the original on 20 September 2007. Retrieved 26 March 2009.
- "How is bronchopulmonary dysplasia diagnosed?". U.S. Department of Health & Human Services. Retrieved 28 September 2008.
- Regillo, Brown & Flynn 1998, p. 178.
- Mitchell, Simon J; Bennett, Michael H; Bird, Nick; Doolette, David J; Hobbs, Gene W; Kay, Edward; Moon, Richard E; Neuman, Tom S; Vann, Richard D; Walker, Richard; Wyatt, HA (2012). "Recommendations for rescue of a submerged unresponsive compressed-gas diver". Undersea & Hyperbaric Medicine : Journal of the Undersea and Hyperbaric Medical Society, Inc 39 (6): 1099–108. PMID 23342767. Retrieved 3 March 2013.
- Clark & Thom 2003, p. 375.
- Lang 2001, p. 195.
- Butler, Frank K.; Thalmann, Edward D. (1986). "Central nervous system oxygen toxicity in closed circuit scuba divers II". Undersea Biomedical Research 13 (2): 193–223. PMID 3727183. Retrieved 29 April 2008.
- Butler, Frank K. (2004). "Closed-circuit oxygen diving in the U.S. Navy". Undersea and Hyperbaric Medicine 31 (1): 3–20. PMID 15233156. Retrieved 29 April 2008.
- Clark & Lambertsen 1970, pp. 157–162.
- Baker, Erik C. (2000). "Oxygen toxicity calculations" (PDF). Retrieved 29 June 2009.
- Hamilton & Thalmann 2003.
- Hamilton R W., Kenyon David J., Peterson R. E., Butler G. J., Beers D. M. (1988). "Repex habitat diving procedures: Repetitive vertical excursions, oxygen limits, and surfacing techniques". Technical Report 88-1A (Rockville, MD: NOAA Office of Undersea Research). Retrieved 29 April 2008.
- Hamilton, Robert W.; Kenyon, David J.; Peterson, R.E. (1988). "Repex habitat diving procedures: Repetitive vertical excursions, oxygen limits, and surfacing techniques". Technical Report 88-1B (Rockville, MD: NOAA Office of Undersea Research). Retrieved 29 April 2008.
- Hamilton, Robert W. (1997). "Tolerating oxygen exposure". South Pacific Underwater Medicine Society Journal 27 (1). ISSN 0813-1988. OCLC 16986801. Retrieved 29 April 2008.
- Latham, Emi (7 November 2008). "Hyperbaric Oxygen Therapy: Contraindications". Medscape. Retrieved 25 September 2008.
- Schatte, C.L. (1977). "Dietary selenium and vitamin E as a possible prophylactic to pulmonary oxygen poisoning". Proceedings of the Sixth International Congress on Hyperbaric Medicine, University of Aberdeen, Aberdeen, Scotland (Aberdeen: Aberdeen University Press): 84–91. ISBN 0-08-024918-3. OCLC 16428246.
- Boadi, W.Y.; Thaire, L.; Kerem, D.; Yannai, S. (1991). "Effects of dietary supplementation with vitamin E, riboflavin and selenium on central nervous system oxygen toxicity". Pharmacology & Toxicology 68 (2): 77–82. doi:10.1111/j.1600-0773.1991.tb02039.x. PMID 1852722.
- Piantadosi, Claude A (2006). In: The Mysterious Malady: Toward an understanding of decompression injuries (DVD). Global Underwater Explorers. Retrieved 2 April 2012.
- Stone, W.L.; Henderson, R.A.; Howard, G.H.; Hollis, A.L.; Payne, P.H.; Scott, R.L. (1989). "The role of antioxidant nutrients in preventing hyperbaric oxygen damage to the retina". Free Radical Biology & Medicine 6 (5): 505–12. doi:10.1016/0891-5849(89)90043-9. PMID 2744583.
- "UK Retinopathy of Prematurity Guideline" (PDF). Royal College of Paediatrics and Child Health, Royal College of Ophthalmologists & British Association of Perinatal Medicine. 2007. p. i. Retrieved 2 April 2009.
- Silverman, William (1980). Retrolental Fibroplasia: A Modern Parable. Grune & Stratton. pp. 39, 41, 143. ISBN 978-0-8089-1264-4.
- Webb, James T.; Olson, R.M.; Krutz, R.W.; Dixon, G.; Barnicott, P.T. (1989). "Human tolerance to 100% oxygen at 9.5 psia during five daily simulated 8-hour EVA exposures". Aviation Space and Environmental Medicine 60 (5): 415–21. doi:10.4271/881071. PMID 2730484.
- Mitchell, Simon J (20 January 2008). "Standardizing CCR rescue skills". RebreatherWorld. Retrieved 26 May 2009. This forum post's author chairs the diving committee of the Underwater and Hyperbaric Medical Society.
- Mitchell, Simon J; Bennett, Michael H; Bird, Nick; Doolette, David J; Hobbs, Gene W; Kay, Edward; Moon, Richard E; Neuman, Tom S; Vann, Richard D; Walker, Richard; Wyatt, HA (2012). "Recommendations for rescue of a submerged unresponsive compressed-gas diver". Undersea & Hyperbaric Medicine : Journal of the Undersea and Hyperbaric Medical Society, Inc 39 (6): 1099–108. PMID 23342767. Retrieved 13 March 2013.
- Thalmann, Edward D (2 December 2003). "OXTOX: If You Dive Nitrox You Should Know About OXTOX". Divers Alert Network. Retrieved 20 October 2008. – Section "What do you do if oxygen toxicity or a convulsion happens?"
- "NIH MedlinePlus: Bronchopulmonary dysplasia". U.S. National Library of Medicine. Retrieved 2 October 2008.
- Regillo, Brown & Flynn 1998, p. 184.
- Lambertsen, Christian J. (1965). "Effects of oxygen at high partial pressure". In: Fenn, W.O.; Rahn, H. (eds.) Handbook of Physiology: Respiration (American Physiological Society). Sec 3 Vol 2: 1027–46.
- "National Institutes of Health: What is bronchopulmonary dysplasia?". U.S. Department of Health & Human Services. Retrieved 2 October 2008.
- Spear, Michael L. – reviewer (June 2008). "Bronchopulmonary dysplasia (BPD)". Nemours Foundation. Retrieved 3 October 2008.
- Regillo, Brown & Flynn 1998, p. 190.
- Gilbert, Clare (1997). "Retinopathy of prematurity: epidemiology". Journal of Community Eye Health (London: International Centre for Eye Health) 10 (22): 22–4.
- Donald, Part II 1947.
- Gerth, Wayne A. (2006). "Decompression sickness and oxygen toxicity in U.S. Navy surface-supplied He-O2 diving". Proceedings of Advanced Scientific Diving Workshop (Smithsonian Institution). Retrieved 2 October 2008.
- Walters, K.C.; Gould, M.T.; Bachrach, E.A.; Butler, Frank K. (2000). "Screening for oxygen sensitivity in U.S. Navy combat swimmers". Undersea and Hyperbaric Medicine 27 (1): 21–6. PMID 10813436. Retrieved 2 October 2008.
- Butler, Frank K.; Knafelc, M.E. (1986). "Screening for oxygen intolerance in U.S. Navy divers". Undersea Biomedical Research 13 (1): 91–8. PMID 3705251. Retrieved 2 October 2008.
- Yildiz, S.; Ay, H.; Qyrdedi, T. (2004). "Central nervous system oxygen toxicity during routine hyperbaric oxygen therapy". Undersea and Hyperbaric Medicine (Undersea and Hyperbaric Medical Society, Inc) 31 (2): 189–90. PMID 15485078. Retrieved 3 October 2008.
- Hampson Neal, Atik D. (2003). "Central nervous system oxygen toxicity during routine hyperbaric oxygen therapy". Undersea and Hyperbaric Medicine (Undersea and Hyperbaric Medical Society, Inc) 30 (2): 147–53. PMID 12964858. Retrieved 20 October 2008.
- Yildiz, S.; Aktas S; Cimsit M; Ay H; Toğrol E. (2004). "Seizure incidence in 80,000 patient treatments with hyperbaric oxygen". Aviation, Space and Environmental Medicine 75 (11): 992–994. PMID 15559001. Retrieved 1 July 2009.
- Bert, Paul (1943) [First published in French in 1878]. Barometric pressure: Researches in Experimental Physiology. Columbus, OH: College Book Company. Translated by: Hitchcock, Mary Alice; Hitchcock, Fred A.
- British Sub-aqua Club (1985). Sport diving : the British Sub-Aqua Club diving manual. London: Stanley Paul. p. 110. ISBN 0-09-163831-3. OCLC 12807848.
- Behnke, Alfred R.; Johnson, F.S.; Poppen, J.R.; Motley, E.P. (1935). "The effect of oxygen on man at pressures from 1 to 4 atmospheres". American Journal of Physiology 110: 565–572. Note: 1 atmosphere (atm) is 1.013 bars.
- Behnke, Alfred R.; Forbes, H.S.; Motley, E.P. (1935). "Circulatory and visual effects of oxygen at 3 atmospheres pressure". American Journal of Physiology 114: 436–442. Note: 1 atmosphere (atm) is 1.013 bars.
- Donald 1992.
- Taylor, Larry "Harris" (1993). "Oxygen Enriched Air: A New Breathing Mix?". IANTD Journal. Retrieved 29 May 2008.
- Davis, Robert H. (1955). Deep Diving and Submarine Operations (6th ed.). Tolworth, Surbiton, Surrey: Siebe Gorman & Company Ltd. p. 291.
- Lambertsen, Christian J.; Clark, John M.; Gelfand, R. (2000). "The Oxygen research program, University of Pennsylvania: Physiologic interactions of oxygen and carbon dioxide effects and relations to hyperoxic toxicity, therapy, and decompression. Summation: 1940 to 1999". EBSDC-IFEM Report No. 3-1-2000 (Philadelphia, PA: Environmental Biomedical Stress Data Center, Institute for Environmental Medicine, University of Pennsylvania Medical Center).
- Vann, Richard D. (2004). "Lambertsen and O2: Beginnings of operational physiology". Undersea and Hyperbaric Medicine 31 (1): 21–31. PMID 15233157. Retrieved 29 April 2008.
- Lang 2001, pp. 81–6.
- Northway, W.H.; Rosan, R.C.; Porter, D.Y. (1967). "Pulmonary disease following respirator therapy of hyaline-membrane disease. Bronchopulmonary dysplasia". New England Journal of Medicine 276 (7): 357–68. doi:10.1056/NEJM196702162760701. PMID 5334613.
- Shennan, A.T.; Dunn, M.S.; Ohlsson, A.; Lennox, K.; Hoskins, E.M. (1988). "Abnormal pulmonary outcomes in premature infants: prediction from oxygen requirement in the neonatal period". Pediatrics 82 (4): 527–32. PMID 3174313.
- Palta, Mari; Sadek, Mona; Barnet, Jodi H. et al. (January 1998). "Evaluation of criteria for chronic lung disease in surviving very low birth weight infants. Newborn Lung Project". Journal of Pediatrics 132 (1): 57–63. doi:10.1016/S0022-3476(98)70485-8. PMID 9470001.
- Natoli, M.J.; Vann, Richard D. (1996). "Factors Affecting CNS Oxygen Toxicity in Humans". Report to the U.S. Office of Naval Research (Durham, NC: Duke University). Retrieved 29 April 2008.
- Hof, D.G.; Dexter, J.D.; Mengel, C.E. (1971). "Effect of circadian rhythm on CNS oxygen toxicity". Aerospace Medicine 42 (12): 1293–6. PMID 5130131.
- Torley, L.W.; Weiss, H.S. (1975). "Effects of age and magnesium ions on oxygen toxicity in the neonate chicken". Undersea Biomedical Research 2 (3): 223–7. PMID 15622741. Retrieved 20 September 2008.
- Troy, S.S.; Ford, D.H. (1972). "Hormonal protection of rats breathing oxygen at high pressure". Acta Neurologica Scandinavica 48 (2): 231–42. doi:10.1111/j.1600-0404.1972.tb07544.x. PMID 5061633.
- Hart, George B.; Strauss, Michael B. (2007). "Gender differences in human skeletal muscle and subcutaneous tissue gases under ambient and hyperbaric oxygen conditions". Undersea and Hyperbaric Medicine 34 (3): 147–61. PMID 17672171. Retrieved 20 September 2008.
- Shykoff, Barbara E. (2007). "Performance of various models in predicting vital capacity changes caused by breathing high oxygen partial pressures". Nedu-Tr-07-13 (Panama City, FL: U.S. Naval Experimental Diving Unit Technical Report). Retrieved 6 June 2008.
- British Sub-Aqua Club (2006). "The Ocean Diver Nitrox Workshop" (PDF). British Sub-Aqua Club. p. 6. Retrieved 15 September 2010.
- Bren, Linda (November–December 2002). "Oxygen Bars: Is a Breath of Fresh Air Worth It?". FDA Consumer magazine. Retrieved 26 June 2009.
- O2Planet (2006). "O2 Planet – Exercise and Fitness Equipment". O2Planet LLC. Retrieved 21 October 2008.
- Verne, Jules (2004) . A Fantasy of Dr Ox. Hesperus Press. ISBN 978-1-84391-067-1. Retrieved 8 May 2009. Translated from French.
- Verne, Jules (1877) . "VIII" [At seventy-eight thousand one hundred and fourteen leagues]. Autour de la Lune [Round the Moon]. London: Ward Lock. ISBN 2-253-00587-8. Retrieved 2 September 2009. Translated from French.
- Clark, James M.; Thom, Stephen R. (2003). "Oxygen under pressure". In Brubakk, Alf O.; Neuman, Tom S. Bennett and Elliott's physiology and medicine of diving (5th ed.). United States: Saunders. pp. 358–418. ISBN 978-0-7020-2571-6. OCLC 51607923.
- Clark, John M.; Lambertsen, Christian J. (1970). "Pulmonary oxygen tolerance in man and derivation of pulmonary oxygen tolerance curves". IFEM Report No. 1-70 (Philadelphia, PA: Environmental Biomedical Stress Data Center, Institute for Environmental Medicine, University of Pennsylvania Medical Center). Retrieved 29 April 2008.
- Donald, Kenneth W. (1947). "Oxygen Poisoning in Man: Part I". British Medical Journal 1 (4506): 667–672. doi:10.1136/bmj.1.4506.667. PMC 2053251. PMID 20248086.
- Donald, Kenneth W. (1947). "Oxygen Poisoning in Man: Part II". British Medical Journal 1 (4507): 712–717. doi:10.1136/bmj.1.4507.712. PMC 2053400. PMID 20248096.
- Revised version of Donald's articles also available as:
- Donald, Kenneth W. (1992). Oxygen and the diver. UK: Harley Swan, 237 pages. ISBN 1-85421-176-5. OCLC 26894235.
- Hamilton, Robert W.; Thalmann, Edward D. (2003). "Decompression practice". In Brubakk, Alf O.; Neuman, Tom S. Bennett and Elliott's physiology and medicine of diving (5th ed.). United States: Saunders. pp. 475–479. ISBN 978-0-7020-2571-6. OCLC 51607923.
- Lang, Michael A., ed. (2001). DAN nitrox workshop proceedings. Durham, NC: Divers Alert Network, 197 pages. Retrieved 20 September 2008.
- Regillo, Carl D.; Brown, Gary C.; Flynn, Harry W. (1998). Vitreoretinal Disease: The Essentials. New York: Thieme, 693 pages. ISBN 978-0-86577-761-3. OCLC 39170393.
- Lamb, John S. (1999). The Practice of Oxygen Measurement for Divers. Flagstaff: Best Publishing, 120 pages. ISBN 0-941332-68-3. OCLC 44018369.
- Lippmann, John; Bugg, Stan (1993). The Diving Emergency Handbook. Teddington, UK: Underwater World Publications. ISBN 0-946020-18-3. OCLC 52056845.
- Lippmann, John; Mitchell, Simon (2005). "Oxygen". Deeper into Diving (2nd ed.). Victoria, Australia: J.L. Publications. pp. 121–4. ISBN 0-9752290-1-X. OCLC 66524750.
The following external site is a compendium of resources:
- Rubicon Research Repository. – Online collection of the oxygen toxicity research
The following external sites contain resources specific to particular topics:
- 2008 Divers Alert Network Technical Diving Conference. – Video of "Oxygen Toxicity" lecture by Dr. Richard Vann (free download, mp4, 86MB).
- Physiology at MCG 4/4ch7/s4ch7_7. – Wide and detailed discussion of the effects of breathing oxygen on the respiratory system.
- Rajiah, Prabhakar (11 March 2009). "Bronchopulmonary Dysplasia". eMedicine. Retrieved 29 June 2009. – Concise clinical overview with extensive references. | <urn:uuid:a5176acc-bad8-4950-8bee-fb945c56b895> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422122220909.62/warc/CC-MAIN-20150124175700-00118-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 4,
"language": "en",
"language_score": 0.8249560594558716,
"score": 3.515625,
"token_count": 14795,
"url": "http://en.wikipedia.org/wiki/Oxygen_toxicity"
} |
Includes an equal part of paper and electronically produced documents
Which of the following is not a description of a hybrid health record?
Version control is unnecessary.
Which of the following is not a true statement about a hybrid health record system?
Tasks that need to be performed in a specific sequence
Incorporating a workflow function in an electronic information system would help support:
Use mirrored processing on redundant servers
Which of the following would be the best course of action to take to ensure continuous availability of electronic data?
Electronic document management system
Which of the following technologies would allow a hospital to get as much medical record information online as quickly as possible?
Clinical data repository
Which of the following technologies would be best for a hospital to use to manage data from its laboratory, pharmacy, and radiology information systems?
Which of the following encourages patients to take an active role in collecting and storing their health information?
Which of the following is necessary to ensure that each term used in an EHR has a common meaning to all users?
Ensures that appropriate data are collected
Why does an ideal EHR system include point-of-care template charting?
Electronic document management system
Which of the following is a transition strategy to achieve an EHR?
Pharmacy information system
To ensure that a computerized provider order entry (CPOE) system supports patient safety, what other system must also be in place?
Before contracting for an EHR product
As part of an EHR system selection, due diligence should be done:
Which form of wireless technology uses infrared light waves to beam data between devices in close proximity to one another?
A step-by-step approach to installing, testing, training, and gaining adoption for an EHR is referred to as:
Electronic point-of-care charting
Electronic systems used by nurses and physicians to document assessments and findings are called:
A SNF wanting to collect MDS assessments in a database and transmit them in a standard CMS format would use which of the following data entry software?
Data represent basic facts, while information represents meaning.
What is the difference between data and information?
Structure and content
Information standards that provide clear descriptors of data elements to be included in computer-based patient record systems are called __________ standards.
Computer software programs that assist in the assignment of codes used with diagnostic and procedural classifications are called:
Laboratory data are successfully transmitted back and forth from Community Hospital to three local physician clinics. This successful transmission is dependent on which of the following standards?
Harmonization of standards from multiple sources
Since many private and public standards groups promulgate health informatics standards, the Office of the National Coordinator of Health Information Technology has been given responsibility for:
As a health information professional, you've become involved in developing an HIE in your region. The agency that would provide the best resources for HIE development is:
Which of the following vocabularies is likely to be used to describe drugs in clinically relevant form?
When some computers are used primarily to enter data and others to process data, the architecture is called:
Set of technologies, standards, applications, systems, values, and laws
Which of the following best describes the national health information infrastructure proposed by the National Committee on Vital and Health Statistics?
In order to effectively transmit healthcare data between a provider and payer, both parties must adhere to which electronic data interchange standards?
Print out all documents and maintain these as a general practice
In attempting to control the patient safety issues associated with hybrid medical records, which of the following would be the best practice for a healthcare facility to do?
Which of the following describes the step during implementation when data from an old system are able to be incorporated into the new system?
Clinical professionals who provide direct patient care
Who are the primary users of the health record for delivery of healthcare services?
Natural language processing
Which of the following types of electronic data entry applies sophisticated mathematical and probabilistic formulas to narrative text and converts them to structured data?
Use radio buttons to select multiple items from a set of options.
Which of the following is not true of good electronic forms design?
Clinical forms committee
What committee usually oversees the development and approval of new forms for the health record?
Identity matching algorithm
The key for linking data about an individual who is seen in a variety of care settings is:
Patient registration department
The first point of data collection and the area where the health record number is most commonly assigned in an acute care hospital is the:
Serial numbering system
In which of the following systems does an individual receive a unique numerical identifier for each encounter with a healthcare facility?
Incomplete records that are not completed by the physician within the time frame specified in the healthcare facility's policies and procedures are called:
EHR project manager
Which of the following individuals is responsible for ensuring that the steps in an EHR implementation are performed and coordinated among the various organization teams, committees, and vendor staff?
Which type of health record is designed to measure clinical outcomes, collect data at the point of care, and provide medical alerts?
Which of the following computer architectures uses a single large computer to process data received from terminals into which data are entered?
A transition technology used by many hospitals to increase access to medical record content is:
When a hospital develops its EHR system by selecting one vendor to provide financial and administrative applications and another vendor to supply the clinical applications, this is commonly referred to as a __________ strategy.
Best of breed
When a hospital develops its electronic health record system by selecting multiple vendors to supply all of its applications including financial, administrative, and clinical applications, this is commonly referred to as a strategy.
Social Security number
Which of the following should not be used as a patient identifier in an electronic environment?
Added to the health record after it has been processed by the HIM department
"Loose" reports are health record forms that are:
In a paper-based system, the completion of the chart is monitored in a special area of the HIM department called the __________ file.
Consider the following sequence of numbers. What filing system is being used if these numbers represent the health record numbers of three records filed together within the filing system? 36-45-99 / 37-45-99 / 38-45-99
The MPI is necessary to physically locate health records within the paper-based storage system for all types of filing systems, except:
25 hours per day
The RHIT supervisor for the filing and retrieval section of Community Clinic is developing a staffing schedule for the year. The clinic is open 260 days per year and has an average of 600 clinic visits per day. The standard for filing records is 60 records per hour. The standard for retrieval of records is 40 records per hour. Given these standards, how many filing hours will be required daily to retrieve and file records for each clinic day?
Unit numbering system
In which of the following systems are all encounters or patient visits filed or linked together?
Uneven expansion of file shelves or cabinets
Which of the following is a disadvantage of alphabetic filing?
File the record alphabetically by the last name, followed by alphabetical order of the first name, and then alphabetical order of the middle initial.
Which of the following statements describes alphabetical filing?
Which of the following tools is usually used to track paper-based health records that have been removed from their permanent storage locations?
Which of the following features of the filing folder helps best to locate misfiles within the paper-based filing system?
Transaction processing system
What type of information system would be used for processing patient admissions, employee time cards, and purchase orders?
A healthcare enterprise wants to analyze data from multiple computer systems across the organization to determine trends in patient care services. Which of the following would best consolidate data for this purpose?
A system that manages data for an entire healthcare business is referred to as a(n):
Transmitters, receivers, media, and data
What basic components make up every electronic network communications system?
The first computer systems used in healthcare were used primarily to perform payroll and __________ functions.
Exchange data from any system within the organization
The concept of systems interoperability refers to the healthcare organization's ability to:
Bidding for the contract
The RFP generally includes a detailed description of the system's requirements and provides guidelines for vendors to follow in:
The most common approaches to converting from an old information system to a new one are the parallel approach, the phased approach, and the __________ approach.
Clinical information system
Which of the following systems is designed primarily to support patient care by providing healthcare professionals access to timely, complete, and relevant information for patient care purposes?
Laboratory information system
Which of the following information systems is used for collecting, verifying, and reporting test results?
Clinical decision support system
Which of the following information systems is used to assist healthcare providers in the actual diagnosis and treatment of patients?
Financial information system
Which of the following information systems is considered an administrative information system?
In which phase of the systems development life cycle is the primary focus on examining the current system and problems in order to identify opportunities for improvement or enhancement of the system?
In which phase of the systems development life cycle are trial runs of the new system conducted, backup and disaster recover procedures developed, and training of end users conducted?
Business and strategic issues
What is the main focus of the system planning phase of the systems development life cycle?
A computer station that engages patients in healthcare organization's services
Which of the following best describes the function of kiosks?
A medication being ordered is contraindicated due to a patient allergy. The physician is notified. This is an example of a(n):
Historical data used for strategic decision support
Which of the following best describes a data warehouse?
Which of the following systems supports the creation, organization, and dissemination of business expertise throughout the organization?
Management information system
Which of the following systems would the HIM department director use to receive daily reports on the number of new admissions to, and discharges from, the hospital?
Which of the following is a snapshot in time and consolidates data from multiple sources to enhance decision making?
Which of the following uses artificial intelligence techniques to capture the knowledge of human experts and to translate and store it in a knowledge base?
Which of the following stores data in predefined tables consisting of rows and columns?
Which of the following is a technique for graphically depicting the structure of a computer database?
Which of the following is a fifth-generation programming language that uses human
language to allow users to speak to computers in a more conversational way?
Which of the following connects computers together in a way that allows for the sharing of information and resources?
Which of the following is a network that connects computers in a relatively small area, such as a room or a building?
Allow healthcare providers to readily access information about a patient's healthcare at any point in time
The primary purpose of the Continuity of Care Record (CCR) is to:
In a network environment, a database shared among several end-user workstations would be stored on a:
Which of the following is a type of computer network specifically designed to allow direct communication between the networks of separate companies?
Which of the following enables sharing resources such as printers or disk space across a computer network?
Online medical supply purchasing
Which of the following best describes B2B e-commerce in a healthcare environment?
Application service provider
Companies that deliver, manage, and remotely host systems, such as an EMR or patient registration software via a network through an outsourcing contract are known as a(n):
Which of the following protocols is used to transfer and display information in the form of Web pages on browsers?
Which of the following is a family of standards that aid the exchange of data among hospital systems and physician practices?
Which of the following translate digital data into analog data so that data can be transmitted over telephone lines and received by a remote computer?
The data type should be changed to Character
The following descriptors about the data element PATIENT_LAST_NAME are included in a data dictionary: definition: legal surname of the patient; data type: numeric; field length: 50; required field: yes; default value: none; input mask: none. Which of the following is true about the definition of this data element?
The coding supervisor wants a daily report of health records that need to be coded. Which of the following systems would be best in meeting the supervisor's needs?
The type of testing of a new electronic information system that ensures that the system can adequately handle a large number of users or transactions is:
A clinic wants to purchase a new healthcare information system. Who is responsible for preparing the RFP to gather information about the functionality of the new system?
'Which of the following are used to associate relationships between entities (tables) in a relational database?
Validation rules for values in a field
In an EMR database, which of the following would be considered an integrity constraint?
Which of the following is a process that identifies patterns and relationships by searching through large amounts of data?
Which of the following types of network topologies has the least chance of failure for bringing down the entire computer network?
Which of the following would be used as an Internet standard for e-mail transmission across Internet protocol (IP) networks?
For at least 5 years
In the absence of state or federal law, AHIMA's retention standards recommend that diagnostic images such as x-rays be maintained:
For at least 10 years after the most recent encounter
In the absence of state or federal law, AHIMA's retention standards recommend that the health records of adults be maintained:
Security awareness program
Which of the following is not an automatic application control that helps preserve data confidentiality and integrity in an electronic system?
Access to information
Within the context of data security, protecting data privacy means defending or safeguarding:
The protection measures and tools for safeguarding information and information systems is a definition of:
The __________ provide(s) the objective and scope for the HIPAA Security rule as a whole.
The covered entity must conduct a risk assessment to determine if the specification is appropriate to its environment.
For HIPAA security implementation specifications that are addressable, which of the following statements is true?
Computer shutdowns caused by intentional or unintentional events
The primary reason that healthcare organizations develop business continuity plans is to minimize the effects of:
Physical access controls
Which of the following are security safeguards that protect equipment, media, and facilities?
Establish a contingency plan
Which of the following must covered entities do in order to comply with HIPAA security provisions?
Data must be encrypted when deemed appropriate from the results of a risk assessment.
Which of the following statements is true regarding HIPAA standards for encryption?
Which of the following are security controls built into a computer software program?
Which of the following are designed to prevent damage caused by computer hackers using the Internet?
Which of the following are policies and procedures required by HIPAA that address the management of computer resources and security?
The mechanisms for safeguarding information and information systems
Which of the following best describes information security?
In the context of data security, which of the following terms means that data should be complete, accurate, and consistent?
Business continuity plan
Which of the following is an organization's planned response to protect its information in the case of a natural disaster?
Once a year
To ensure relevancy, an organization's security policies and procedures be reviewed at least:
Which of the following is a software program that tracks every access to data in the computer system?
Fully digital EHR system
A clinic is evaluating options for an EHR system. The selection committee wants a system that provides simultaneous access to the record by different providers and administrative services employees. It also wants the system to perform various types of data analyses on discrete data. The system must electronically store forms and information so paper storage is completely eliminated. Which of the following would be the best fit for the requirements the committee wants?
Implement a document scanning system for the paper records and interface data created in the current EHR with the document scanning system
A hospital is concerned about the difficulty in retrieving health records for patient care and legal purposes. Some of its data are stored electronically while the remainder are stored on paper. The hospital knows it will be several years before it will be able to implement an entire EHR system and go paperless. Given this information, which of the following would be the best solution for the hospital to ensure that all of the data for a patient are retrieved when needed?
A system whereby documents are scanned by a document imaging system and then integrated and indexed into the existing EHR
Which of the following hybrid models comes closest to a total EHR system?
Shading of bars or lines that contain text
Which of the following should be avoided when designing forms for an EDMS?
24 lb. weight paper for double-sided forms
Which of the following is recommended for design of forms for an EDMS?
Implement session terminations
A hospital is planning on allowing coding professionals to work at home. The hospital is in the process of identifying strategies to minimize the security risks associated with this practice. Which of the following would be best to ensure that workstations are not left unattended at home offices?
User name, password, and security question
A home health agency plans to implement a computer system that permits nursing documentation on a laptop computer taken to the patient's home. The agency is in the process of identifying strategies to minimize the risks associated with the practice. With regard to access to data on the laptop, which of the following would be best for securing data?
Ask the security officer for audit trail data to confirm or disprove the suspicion
The HIM supervisor suspects that a departmental employee is using the Internet for personal business but has no specific data to support this suspicion. In this case, what should the supervisor do?
Scan all documents at the time of patient discharge
A HIM department is researching various options for scanning the hospital's health records. The department director would like to achieve efficiencies through scanning such as performing coding and cancer registry functions remotely. Given these considerations, which of the following would be the best scanning process?
Document name, media type, source system, electronic storage start date, stop printing start date
Which of the following data sets would be most useful in developing a grid for identification of components of the legal health record in a hybrid record environment?
What component of the departmental budget would include the expense of purchasing new reference books for clinical coding staff?
Which of the following is capable of providing video, audio, computer, and imaging system connectivity for virtual teamwork?
Determination of the quickest solution
Which of the following is not a step in quality improvement decision-making?
Be dedicated to achieving the organizational vision
During times of change, it is important for the supervisor to:
Environmental assessments are performed as part of which of the following processes?
Which of the following is a description of what the organization would like to be in the future?
A summary of the job position, a list of duties, and the qualifications required to perform the job are all elements of a(n):
The organizational structure affects the way its employees interact with each other
One unchanging principle of organizational behavior is that:
On the job training
Which of the following provides direct, realistic training in the specific tasks required by the job position?
Which of the following describes the type of behavior the organization wants to encourage among its employees?
A coding supervisor who makes up the weekly work schedule would engage in what type of planning?
360 degree evaluation
Which of the following would the supervisor and peers contribute to an individual's performance evaluation? | <urn:uuid:4f999077-1ed0-4155-846f-7b1580d427ae> | {
"dataset": "HuggingFaceFW/fineweb-edu",
"dump": "CC-MAIN-2015-06",
"file_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422115860277.59/warc/CC-MAIN-20150124161100-00098-ip-10-180-212-252.ec2.internal.warc.gz",
"int_score": 3,
"language": "en",
"language_score": 0.9268860220909119,
"score": 2.71875,
"token_count": 4131,
"url": "http://quizlet.com/15742684/domain-iii-information-technology-flash-cards/"
} |
"The Index of Dependence on Government measures the growth in spending on dependence-creating progra(...TRUNCATED) | <urn:uuid:0408ba23-ce7f-465e-b2d7-ba22799bfc23> | {"dataset":"HuggingFaceFW/fineweb-edu","dump":"CC-MAIN-2018-13","file_path":"s3://commoncrawl/crawl-(...TRUNCATED) |
"Type 2 Diabetes\nType 2 diabetes is a chronic disease in which your body is unable to maintain a no(...TRUNCATED) | <urn:uuid:cbaedf99-0742-4399-a024-5ce02fb70700> | {"dataset":"HuggingFaceFW/fineweb-edu","dump":"CC-MAIN-2018-13","file_path":"s3://commoncrawl/crawl-(...TRUNCATED) |
"Type 2 Diabetes\nType 2 diabetes is a chronic disease in which your body is unable to maintain a no(...TRUNCATED) | <urn:uuid:fea405db-300f-4ef7-88ce-5f138ecfc546> | {"dataset":"HuggingFaceFW/fineweb-edu","dump":"CC-MAIN-2018-13","file_path":"s3://commoncrawl/crawl-(...TRUNCATED) |
"Type 2 Diabetes\nType 2 diabetes is a chronic disease in which your body is unable to maintain a no(...TRUNCATED) | <urn:uuid:99f3d8a8-8cf7-4ea7-b6e7-272352416ce7> | {"dataset":"HuggingFaceFW/fineweb-edu","dump":"CC-MAIN-2018-13","file_path":"s3://commoncrawl/crawl-(...TRUNCATED) |
End of preview. Expand
in Data Studio
README.md exists but content is empty.
- Downloads last month
- 746