First-Hand:The Foundation of Digital Television: the origins of the 4:2:2 component digital standard
Contributed by Stanley Baron, IEEE Life Fellow
By the late 1970's, the application of digital technology in television production was widespread. A number of digital television products had become available for use in professional television production. These included graphics generators, recursive filters (noise reducers), time base correctors and synchronizers, standards converters, amongst others.
However, each manufacturer had adopted a unique digital interface, and this meant that these digital devices when formed into a workable production system had to be interfaced at the analog level, thereby forfeiting many of the advantages of digital processing.
Most broadcasters in Europe and Asia employed television systems based on 625/50 scanning (625 lines per picture, repeated 50 fields per second), with the PAL color encoding system used in much of Western Europe, Australia, and Asia, while France, the Soviet Union, Eastern Europe, and China used variations of the SECAM color encoding system. There were differences in luminance bandwidth: 5.0 MHz for B/G PAL, 5.5 MHz for PAL in the UK and nominally 6 MHz for SECAM. There were also legacy monochrome systems, such as 405/50 scanning in the UK and the 819/50 system in France. The color television system that was dominate in the Americas, Japan, and South Korea was based on 525/60 scanning, 4.2 MHz luminance bandwidth, and the NTSC color standard.
NTSC and PAL color coding are both linear processes. Therefore, analog signals in the NSTC format could be mixed and edited during studio processing, provided that color sub carrier phase relationships were maintained. The same was true for production facilities based on the PAL system. In analog NTSC and PAL studios it was normal to code video to composite form as early as possible in the signal chain so that each signal required only one wire for distribution rather than the three needed for RGB or YUV component signals. The poor stability of analog circuitry meant that matching separate channel RGB or YUV component signals was impractical except in very limited areas. SECAM employed frequency modulated coding of the color information, which did not allow any processing of composite signals, so the very robust SECAM composite signal was used only on videotape recorders and point to point links, with decoding to component signals for mixing and editing. Some SECAM broadcasters avoided the problem by operating their studios in PAL and recoding to SECAM for transmission.
The international community recognized that the world community would be best served if there could be an agreement on a single production or studio digital interface standard regardless of which color standard (525 line NTSC, 625 line PAL, or 625 line SECAM) was employed for transmission. The cost of implementation of digital technology was seen as directly connected to the production volume; the higher the volume, the lower the cost to the end user, in this case, the broadcasting community.
Work on determining a suitable standard was organized by the Society of Motion Picture Engineers (SMPTE) on behalf of the 525/60 broadcasting community and the European Broadcasting Union (EBU) on behalf of the 625/50 broadcasting community.
In 1982, the international community reached agreement on a common 4:2:2 Component Digital Television Standard. This standard as documented in SMPTE 125, several EBU Recommendations, and ITU-R Recommendation 601 was the first international standard adopted for interfacing equipment directly in the digital domain avoiding the need to first restore the signal to an analog format.
The interface standard was designed so that the basic parameter values provided would work equally well in both 525 line/60 Hz and 625 line/50 Hz television production environments. The standard was developed in a remarkably short time, considering its pioneering scope, as the world wide television community recognized the urgent need for a solid basis for the development of an all digital television production system. A component-based (Y, R-Y, B-Y) system based on a luminance (Y) sampling frequency of 13.5 MHz was first proposed in February 1980; the world television community essentially agreed to proceed on a component based system in September 1980 at the IBC; a group of manufacturers supplied devices incorporating the proposed interface at a SMPTE sponsored test demonstration in San Francisco in February 1981; most parameter values were essentially agreed to by March 1981; and the ITU-R (then CCIR) Plenary Assembly adopted the standard in February 1982.
What follows is an overview of this historic achievement, providing a history of the standard's origins, explaining how the standard came into being, why various parameter values were chosen, the process that led the world community to an agreement, and how the 4:2:2 standard led to today's digital high definition production standards and digital broadcasting standards.
It is understood that digital processing of any signal requires that the sample locations be clearly defined in time and space and, for television, processing is simplified if the samples are aligned so that they are line, field, and frame position repetitive yielding an orthogonal (rectangular grid) sampling pattern.
While the NTSC system color sub carrier frequency (fsc) was an integer sub multiple of the horizontal line frequency (fH) [fsc = (m/n) x fH] lending itself to orthogonal sampling, the PAL system color sub carrier employed a field frequency off set and the SECAM color system employed frequency modulation of the color subcarrier, which made sampling the color information, contained within those systems a more difficult challenge. Further, since some European nations had adopted various forms of the PAL 625 line/50Hz composite color television standard as their broadcast standard and other European nations had adopted various forms of the SECAM 625 line/50Hz composite color television standard, the European community's search for a common digital interface standard implied that a system that was independent of the color coding technique used for transmission would be required.
Developments within the European community
In September 1972, the European Broadcasting Union (EBU) formed Working Party C, chaired by Peter Rainger to investigate the subject of coding television systems. In 1977, based on the work of Working Party C, the EBU issued a document recommending that the European community consider a component television production standard, since a component signal could be encoded as either a PAL or SECAM composite signal just prior to transmission.
At a meeting in Montreux, Switzerland in the spring of 1979, the EBU reached agreement with production equipment manufacturers that the future of digital program production in Europe would be best served by component coding rather than composite coding, and the EBU established a research and development program among its members to determine appropriate parameter values. This launched an extensive program of work within the EBU on digital video coding for program production. The work was conducted within a handful of research laboratories across Europe and within a reorganized EBU committee structure including: Working Party V on New Systems and Services chaired by Peter Rainger; subgroup V1 chaired by Yves Guinet, which assumed the tasks originally assigned to Working Party C; and a specialist supporting committee V1 VID (Vision) chaired by Howard Jones. David Wood, representing the EBU Technical Center, served as the secretariat of all of the EBU committees concerned with digital video coding.
In 1979, EBU VI VID proposed a single three channel (Y, R-Y, B-Y) component standard. The system stipulated a 12.0 MHz luminance (Y) channel sampling frequency and provided for each of the color difference signals (R-Y and B-Y) to be sampled at 4.0 MHz. The relationship between the luminance and color difference signals was noted sometimes as (12:4:4) and sometimes as (3:1:1). The proposal, based on the results of subjective quality evaluations, suggested these values were adequate to transparently deliver 625/50i picture quality.
The EBU Technical Committee endorsed this conclusion at a meeting in April 1980, and instructed its technical groups: V, V1, and V1 VID to support this effort.
SMPTE organized for the task at hand
Three SMPTE committees were charged with addressing various aspects of world wide digital standards. The first group, organized in late 1974, was the Digital Study Group chaired by Charles Ginsburg. The Study Group was charged with investigating all issues concerning the application of digital technology to television. The second group was a Task Force on Component Digital Coding with Frank Davidoff as chairman. This Task Force, which began work in February 1980, was charged with developing a recommendation for a single worldwide digital interface standard. While membership in SMPTE committees is generally open to any interested and affected party, the membership of the Task Force had been limited to recognized experts in the field. The third group was the Working Group on Digital Video Standards. This Working Group was charged with documenting recommendations developed by the Study Group or the Task Force and generating appropriate standards, recommended practices, and engineering guidelines.
In March 1977, the Society of Motion Picture and Television Engineers (SMPTE) began development of a digital television interface standard. The work was assigned by SMPTE's Committee on New Technology chaired by Fred Remley to the Working Group on Digital Video Standards chaired by Dr. Robert Hopkins.
By 1979, the Working Group on Digital Video Standards was completing development of a digital interface standard for NTSC television production. Given the state of the art at the time and the desire to develop a standard based on the most efficient mechanism, the Working Group created a standard that allowed the NTSC television video signal to be sampled as a single composite color television signal. It was agreed after a long debate on the merits of three times sub carrier (3fsc) versus four times sub carrier (4fsc) sampling that the Composite Digital Television Standard would require the composite television signal with its luminance channel and color sub carrier to be sampled at four times the color sub carrier frequency (4fsc) or 14.31818... MHz.
During the last quarter of 1979, agreement was reached on a set of parameter values, and the drafting of the Composite Digital Television Standard was considered completed. It defined a signal sampled at 4fsc with 8 bit samples. This standard seemed to resolve the problem of providing a direct digital interface for production facilities utilizing the NTSC standard.
By 1980, the Committee on New Technology was being chaired by Hopkins and the Working Group on Digital Video Standards was being chaired by Ken Davies.
Responding to communications with the EBU and so as not to prejudice the efforts being made to reach agreement on a world wide component standard, in January 1980, Hopkins put the finished work on the NTSC Composite Digital Television Standard temporarily aside so that any minor modifications to the document that would serve to meet possible world wide applications could be incorporated before final approval. Since copies of the document were bound in red binders, the standard was referred to as the "Red Book".
Seeking a Common Reference
The agenda of the January 1980 meeting of SMPTE's Digital Study Group included a discussion on a world wide digital television interface standard. At that meeting, the Study Group considered the report of the European community, and members of the EBU working parties had been invited to attend. Although I was not a member of the Study Group, I was also invited to attend the meeting.
It was recognized that while a three color representation of the television signal using Red, Blue, and Green (R, G, B) was the simplest three component representation, a more efficient component representation, but one that is more complex, is to provide a luminance or gray scale channel (Y) and two color difference signals (R-Y and B-Y). The R-Y and B-Y components take advantage of the characteristics of the human visual system which is less sensitive to high resolution information for color than for luminance. This allows for the use of a lower number of samples to represent the color difference signals without observable losses in the restored images. Color difference components (noted as I, Q or U, V or Dr, Db) were already in use in the NTSC, PAL, and SECAM systems to reduce the bandwidth required to support color information.
Members of the NTSC community present at the January 1980 Study Group meeting believed that the EBU V1 VID proposed 12.0 MHz, (3:1:1) set of parameters would not meet the needs for NTSC television post production particularly with respect to chroma keying, then becoming an important tool. In addition, it was argued that: (1) the sampling frequency was too low (too close to the Nyquist point) for use in a production environment where multiple generations of edits were required to accommodate special effects, chroma keying, etc., and (2) a 12.0 MHz sampling system would not produce an orthogonal array of samples in NTSC (at 12.0 MHz, there would be 762.666... pixels per line).
The NTSC community offered for consideration a single three channel component standard based on (Y, R-Y, B-Y). This system stipulated a 4fsc (14.318 MHz) luminance sampling frequency equal to 910 x fH525, where fH525 is the NTSC horizontal line frequency. The proposal further provided for each of the color difference components to be sampled at 2fsc or 7.159 MHz. This relationship between the luminance and color difference signals was noted as (4:2:2). Adopting 4fsc as the luminance sampling frequency would facilitate trans coding of video recorded using the “single wire” NTSC composite standard with studio mixers and editing equipment based on a component video standard.
Representatives of the European television community present at the January 1980 Study Group meeting pointed to some potential difficulties with this proposal. The objections included: (1) that the sampling frequency was too high for use in practical digital recording at the time, and (2) a 14.318 MHz sampling system would not produce an orthogonal array of samples in a 625 line system (at 14.318 MHz, there would be 916.36... pixels per line).
During the January 1980 Study Group meeting discussion, I asked why the parties involved had not considered a sampling frequency that was a multiple of the 4.5 MHz sound carrier, since the horizontal line frequencies of both the 525 line and 625 line systems had an integer relationship to 4.5 MHz.
The original definition of the NTSC color system established a relationship between the sound carrier frequency (fs) and the horizontal line frequency (fH525) as fH525 = fs/286 = 15734.265... Hz, had further defined the vertical field rate fV525 = (fH525 x 2)/525 = 59.94006 Hz, and defined the color sub carrier (fsc) = (fH525 x 455)/2 = 3.579545.... MHz. Therefore, all the frequency components of the NTSC system could be derived as integer sub multiples of the sound carrier.
The 625 line system defined the horizontal line frequency (fH625) = 15625 Hz and the vertical field rate fV625 = (fH625 x 2)/625 = 50 Hz. It was noted from the beginning that the relationship between fs and the horizontal line frequency (fH625) could be expressed as fH625 = fs/288. Therefore, any sampling frequency that was an integer multiple of 4.5 MHz (fs) would produce samples in either the 525 line or 625 line systems that were orthogonal.
I was asked to submit a paper to the Study Group and the Task Force describing the relationship. The assignment was to cover two topics. The first topic was how the 625 line/50Hz community might arrive at a sampling frequency close to 14.318 MHz. The second topic was to explain the relationship between the horizontal frequencies of the 525 line and 625 line systems and 4.5 MHz.
This resulted in my authoring a series of papers written between February and April 1980 addressed to the SMPTE Task Force explaining why 13.5 MHz should be considered the choice for a common luminance sampling frequency. The series of papers was intended to serve as a tutorial with each of the papers expanding on the points previously raised. A few weeks after I submitted the first paper, I was invited to be a member of the SMPTE Task Force. During the next few months, I responded to questions about the proposal, and I was asked to draft a standards document.
Crunching the numbers
The first paper I addressed to the Task Force was dated 11 February 1980. This paper pointed to the fact that since the horizontal line frequency of the 525 line system (fH525 had been defined as 4.5 MHz/286 (or 2.25 MHz/143), and the horizontal line frequency of the 625 line system (fH625) was equal to 4.5 MHz/288 (or 2.25 MHz/144), any sampling frequency that was a multiple of 4.5 MHz/2 could be synchronized to both systems.
Since it would be desirable to sample color difference signals at less than the sampling rate of the luminance signal, then a sampling frequency that was a multiple of 2.25 MHz would be appropriate for use with the color difference components (R-Y, B-Y) while a sampling frequency that was a multiple of 4.5 MHz would be appropriate for use with the luminance component (Y).
Since the European community had argued that the (Y) sampling frequency must be lower than 14.318 MHz and the NTSC countries had argued that the (Y) sampling frequency must be higher than 12.00 MHz, my paper and cover letter dated 11 February 1980 suggested consideration of 3 x 4.5 MHz or 13.5 MHz as the common luminance (Y) channel sampling frequency (858 times the 525 line horizontal line frequency rate and 864 times the 625 line rate both equal 13.5 MHz).
My series of papers suggested adoption of a component color system based on (Y, R-Y, B-Y) and a luminance/color sampling relationship of (4:2:2), with the color signals sampled at 6.75 MHz. In order for the system to facilitate standards conversion and picture manipulation (such as that used in electronic special effects and graphics generators), both the luminance and color difference samples should be orthogonal. The desire to be able to trans code between component and composite digital systems implied a number of samples per active line that was divisible by four.
The February 1980 note further suggested that the number of samples per active line period should be greater than 715.5 to accommodate all of the world wide community standards active line periods. While the number of pixels per active line equal to 720 samples per line was not suggested until my next note, (720 is the number found in Rec. 601 and SMPTE 125), 720 is the first value that “works.” 716 is the first number greater than 715.5 that is divisible by 4 (716 = 4 x 179), but does not lend itself to standards conversion between 525 line component and composite color systems or provide sufficiently small pixel groupings to facilitate special effects or data compression algorithms. </p>
Additional arguments in support of 720 were provided in notes I generated prior to IBC'80 in September. Note that 720 equals 6! [6! (6 factorial) = 6x5x4x3x2x1] = 24 x 32 x 5. This allows for many small factors, important for finding an economical solution to conversion between the 525 line component and composite color standards and for image manipulation in special effects and analysis of blocks of pixels for data compression. The composite 525 line digital standard had provided for 768 samples per active line. 768 = 28 x 3. The relationship between 768 and 720 can be described as 768/720 = (28 x 3)/(24 x 32 x 5) = (24)/(3 x 5) = 16/15. A set of 16 samples in the NTSC composite standard could be used to calculate a set of 15 samples in the NTSC component standard.
Proof of Performance
At the September 1980 IBC conference, international consensus became focused on the 13.5 MHz, (4:2:2) system. However, both the 12.0 MHz and 14.318 MHz systems retained some support for a variety of practical considerations. Discussions within the Working Group on Digital Video Standards indicated that consensus could not be achieved without the introduction of convincing evidence.
SMPTE proposed to hold a “Component Coded Digital Video Demonstration” in San Francisco in February 1981 organized by and under the direction of the Working Group on Digital Video Standards to evaluate component coded systems. A series of practical tests/demonstrations were organized to examine the merits of various proposals with respect to picture quality, production effects, recording capability and practical interfacing, and to establish an informed basis for decision making.
The EBU had scheduled a series of demonstrations in January 1981 for the same purpose. SMPTE invited the EBU to hold its February meeting of the Bureau of the EBU Technical Committee in San Francisco to be followed by a joint meeting to discuss the results of the tests. It was agreed that demonstrations would be conducted at three different sampling frequencies (near 12.0 MHz, 13.5 MHz, and 14.318 MHz) and at various levels of performance.
From 2nd through the 6th of February 1981 (approximately, one year from the date of the original 13.5 MHz proposal), SMPTE conducted demonstrations at KPIX Television, Studio N facilities in San Francisco in which a number of companies participated. Each participating sponsor developed equipment with the digital interface built to the specifications provided. The demonstration was intended to provide proof of performance and to allow the international community to come to an agreement.
'The demonstration organizing committee had to improvise many special interfaces and interconnections, as well as create a range of test objects, test signals, critical observation criteria, and a scoring and analysis system and methodology.
The demonstrations were supported with equipment and personnel by many of the companies that were pioneers in the development of digital television and included: ABC Television, Ampex Corporation, Barco, Canadian Broadcasting Corporation, CBS Technology Center, Digital Video Systems, Dynair, Inc., KPIX Westinghouse Broadcasting, Leitch Video Ltd., Marconi Electronics, RCA Corporation and RCA Laboratories, Sony Corporation, Tektronix Inc., Thomson CSF, VG Electronics Ltd., and VGR Corporation. I participated in the demonstrations as a member of SMPTE's Working Group on Digital Video Standards, providing a Vidifont electronic graphics generator whose interface conformed to the new standard.
Developing an agreement
The San Francisco demonstrations proved the viability of the 13.5 MHz, (4:2:2) proposal. At a meeting in January 1981, the EBU had considered a set of parameters based on a 13.0 MHz (4:2:2) system. Additional research conducted by EBU members had shown that a (4:2:2) arrangement was needed in order to cope with picture processing requirements, such as chroma key, and the EBU members believed a 13.0 MHz system appeared to be the most economic system that provided adequate picture processing. Members of the EBU and SMPTE committees met at a joint meeting chaired by Peter Rainger in March 1981 and agreed to propose the 13.5 MHz, (4:2:2) standard as the world wide standard. By autumn 1981, NHK in Japan led by Mr. Tadokoro, had performed its own independent evaluations and concurred that the 13.5 MHz, (4:2:2) standard offered the optimum solution.
A number of points were generally agreed upon and formed the basis of a new world wide standard. They included:
- The existing colorimetry of EBU (for PAL and SECAM) and of NTSC would be retained for 625 line and 525 line signals respectively, as matrixing to a common colorimetry was considered overly burdensome;
- An 8 bit per sample representation would be defined initially, being within the state of the art, but a 10 bit per sample representation would also be specified since it was required for many production applications;
- The range of the signal to be included should include head room (above white level) and foot room (below black level) to allow for production overshoots;
- The line length to be sampled should be somewhat wider than those of the analog systems (NTSC, PAL, and SECAM) under consideration to faithfully preserve picture edges and to avoid picture cropping;
- A bit parallel, sample multiplexed interface (e.g. transmitting R-Y, Y, B-Y, Y, R-Y, ...) was practical, but in the long term, a fully bit and word serial system would be desirable;
- The gross data rate should be recordable within the capacity of digital tape recorders then in the development stages by Ampex, Bosch, RCA, and Sony.
The standard, as documented, provided for each digital sample to consist of at least 8 bits, with 10 allowed. The values for the black and white levels were defined, as was the range of the color signal. (R-Y) and (B-Y) became CR [=0.713 (R-Y)] and CB [=0.564 (B-Y)]. While the original note dated February 1980 addressed to the Task Force proposed a code of 252(base10) =(1111 1100) for ‘white’ at 100 IRE and a code of 72 (base10) =(0100 1000) for ‘black’ at 0 IRE to allow capture of the sync levels, agreement was reached to better utilize the range of codes to capture the grey scale values with more precision and provide more overhead. ‘White’ was to be represented by an eight bit code of 240(base10) =(1111 0000) and ‘black’ was to be represented by an eight bit code 16 (base10) =(0001 0000). The original codes for defining the beginning and the end of picture lines and picture area were discussed, modified, and agreed upon, as well as synchronizing coding for line, field, and frame, each coding sequence being unique and not occurring in the video signal.SMPTE and EBU organized an effort over the next few months to familiarize the remainder of the world wide television community with the advantages offered by the 13.5 MHz, (4:2:2) system and the reasoning behind its set of parameters. Members of the SMPTE Task Force traveled to Europe and to the Far East. Members of the EBU committees traveled to the, then, Eastern European block nations and to the members of the OTI, the organization of the South American broadcasters. The objective of these tours was to build a consensus prior to the upcoming discussion at the ITU in the autumn of 1981. The success of this effort could serve as a model to be followed in developing future agreements.
I was asked to draft a SMPTE standard document that listed the parameter values for a 13.5 MHz system for consideration by the SMPTE Working Group. Since copies of the document were bound in a green binder prior to final acceptance by SMPTE, the standard was referred to as the “Green Book”.
In April 1981, the draft of the standard titled “Coding Parameters for a Digital Video Interface between Studio Equipment for 525 line, 60 field Operation” was distributed to a wider audience for comment. This updated draft reflected the status of the standard after the tests in San Francisco and agreements reached at the joint EBU/SMPTE meeting in March 1981. The EBU community later requested a subtle change to the value of ‘white’ in the luminance channel, and it assumed the value of 235(base10). This change was approved in August 1981.
After review and some modification as noted above to accommodate European concerns, the “Green Book” was adopted as SMPTE Standard 125.
ITU/R Recommendation 601
The European Broadcasting Union (EBU) generated an EBU Standard containing a companion set of parameter values. The SMPTE 125 and EBU documents were then submitted to the International Telecommunications Union (ITU). The ITU, a treaty organization within the United Nations, is responsible for international agreements on communications. The ITU Radio Communications Bureau (ITU-R/CCIR) is concerned with wireless communications, including allocation and use of the radio frequency spectrum. The ITU also provides technical standards, which are called “Recommendations.”
Within the ITU, the development of the Recommendation defining the parameter values of the 13.5 MHz (4:2:2) system fell under the responsibility of ITU-R Study Group 11 on Television. The chair of Study Group 11, Prof. Mark I. Krivocheev, assigned the drafting of the document to a special committee established for that purpose and chaired by David Wood of the EBU. The document describing the digital parameters contained in the 13.5 MHz, (4:2:2) system was approved for adoption as document 11/1027 at ITU-R/CCIR meetings in Geneva in September and October 1981. A revised version, document 11/1027 Rev.1, dated 17 February 1982, and titled “Draft Rec. AA/11 (Mod F): Encoding parameters of digital television for studios” was adopted by the ITU-R/CCIR Plenary Assembly in February 1982. It described the digital interface standard for transfer of video information between equipment designed for use in either 525 line or 625 line conventional color television facilities. Upon approval by the Plenary Assembly, document 11/1027 Rev.1 became CCIR Recommendation 601.
The Foundation for HDTV and Digital Television Broadcasting Services
The 4:2:2 Component Digital Television Standard allowed for a scale of economy and reliability that was unprecedented by providing a standard that enabled the design and manufacture of equipment that could operate in both 525 line/60Hz and 625 line/50Hz production environments. The 4:2:2 Component Digital Television Standard permitted equipment supplied by different manufacturers to exchange video and embedded audio and data streams and/or to record and playback those streams directly in the digital domain without having to be restored to an analog signal. This meant that the number of different processes and/or generations of recordings could be increased without the noticeable degradation of the information experienced with equipment based on analog technology. A few years after the adoption of the 4:2:2 Component Digital Television Standard, all digital production facilities were shown to be practical.
A few years later when the ITU defined “HDTV,” the Recommendation stipulated: “the horizontal resolution for HDTV as being twice that of conventional television systems” described in Rec. 601and a picture aspect ratio of 16:9. A 16:9 aspect ratio picture requires one-third more pixels per active line than a 4:3 aspect ratio picture. Rec. 601 provided 720 samples per active line for the luminance channel and 360 samples for each of the color difference signals. Starting with 720, doubling the resolution to 1440, and adjusting the count for a 16:9 aspect ratio leads to the 1920 samples per active line defined as the basis for HDTV. Accommodating the Hollywood and computer communities' request for “square pixels” meant that the number of lines should be 1920 x (9/16) = 1080.
Progressive scan systems at 1280 pixels per line and 720 lines per frame are also a member of the “720 pixel” family. 720 pixels x 4/3 (resolution improvement) x 4/3 (16:9 aspect ratio adjustment) = 1280. Accommodating the Hollywood and computer communities' request for square pixels meant that the number of lines should be 1280 x (9/16) = 720.
The original 720 pixel per active line structure became the basis of a family of structures (the 720 pixel family) that was adopted for MPEG based systems including both conventional television and HDTV systems. Therefore, most digital television systems, including digital video tape systems and DVD recordings are derived from the format described in the original 4:2:2 standard.
The existence of a common digital component standard for both 50 Hz and 60 Hz environments as documented in SMPTE 125 and ITU Recommendation 601 provided a path for television production facilities to migrate to the digital domain. The appearance of high quality, fully digital production facilities providing digital video, audio, and metadata streams and the successful development of digital compression and modulation schemes allowed for the introduction of digital television broadcast services.
In its 1982-1983 award cycle, the National Academy of Television Arts and Sciences recognized the 4:2:2 Component Digital Standard based on 13.5 MHz (Y) sampling with 720 samples per line with three EMMY awards:
The European Broadcasting Union (EBU) was recognized: “For achieving a European agreement on a component digital video studio specification based on demonstrated quality studies and their willingness to subsequently compromise on a world wide standard.”
The International Telecommunications Union (ITU) was recognized: “For providing the international forum to achieve a compromise of national committee positions on a digital video standard and to achieve agreement within the 1978-1982 period.”
The Society of Motion Picture and Television Engineers (SMPTE) was recognized: “For their early recognition of the need for a digital video standard, their acceptance of the EBU proposed component requirement, and for the development of the hierarchy and line lock 13.5 MHz demonstrated specification, which provided the basis for a world standard.”
This narrative is intended to acknowledge the early work on digital component coded television carried out over several years by hundreds of individuals, organizations, and administrations throughout the world. It is not possible in a limited space to list all of the individuals or organizations involved, but by casting a spotlight on the results of their work since the 1960's and its significance, the intent is to honor them - all.
Individuals interested in the specific details of digital television standards and picture formats (i.e. 1080p, 720p, etc.) should inquire at www.smpte.org. SMPTE is the technical standards development organization (SDO) for motion picture film and television production.
- ↑ This article builds on a prior article by Stanley Baron and David Wood; simultaneously published in the SMPTE Motion Imaging Journal, September 2005, pp. 327 334 as “The Foundations of Digital Television: the origins of the 4:2:2 DTV standard" and in the EBU Technical Review, October 2005, as "Rec. 601 the origins of the 4:2:2 DTV standard.”
- ↑ Guinet, Yves; “Evolution of the EBU's position in respect of the digital coding of television”, EBU Review Technical, June 1981, pp.111 117.
- ↑ Davies, Kenneth; “SMPTE Demonstrations of Component Coded Digital Video, San Francisco, 1981”, SMPTE Journal, October 1981, pp.923 925.
- ↑ Fink, Donald; “Television Engineering Handbook”, McGraw Hill [New York, 1957], p.7 4.
- ↑ Baron, S.; “Sampling Frequency Compatibility”, SMPTE Digital Study Group, January 1980, revised and submitted to the SMPTE Task Force on Digital Video Standards, 11 February 1980. Later published in SMPTE Handbook, “4:2:2 Digital Video: Background and Implementation”, SMPTE, 1989, ISBN 0 940690 16, pp.20 23.
- ↑ Weiss, Merrill &amp;amp; Marconi, Ron; “Putting Together the SMPTE Demonstrations of Component Coded Digital Video, San Francisco, 1981”, SMPTE Journal, October 1981, pp.926 938.
- ↑ Davidoff, Frank; “Digital Television Coding Standards”, IEE Proceedings, 129, Pt.A., No.7, September 1982, pp.403 412.
- ↑ Nasse, D., Grimaldi, J.L., and Cayet, A; “An Experimental All Digital Television Center”, SMPTE Journal, January 1986, pp. 13 19.
- ↑ ITU Report 801, “The Present State of High Definition Television”, Part 3, “General Considerations of HDTV Systems”, Section 4.3, “Horizontal Sampling”.


J.S. Bach was born in Eisenach, Germany, in 1685 and died in 1750. He came from a long family history of professional musicians including church organists and composers. Like his father, Johann Ambrosius Bach, J.S. (Johann Sebastian) would learn and surpass him in this art of classical music composing.
Bach's childhood wasn't that great as his father passed away when he was 9 and his mother also died when he was a young boy. Although he spent much time with his musically inclined uncles, he also spent time studying and learning from his older brother, Johann Christoph Bach.
Growing up, Bach learned much about organ building. Back in those days, the church organ was a highly complex instrument with many mechanical and moving parts/pedals and pipes. His early experience with repairing and talking with organ builders & performers would prove valuable as he mastered the musical craft.


I’m struggling a bit to teach my children to pack for themselves. I want them to learn how to be self-reliant, but I also want to make sure they have everything they need for the day. If I don’t triple check every detail, they’re likely to be fully prepared for snack time but missing important papers or sports equipment. What’s the right thing to do?
Your desire to raise self-reliant children is fantastic. But there’s no doubt that passing the baton can be tough. The first question has to be: how old are your children? A good general rule of thumb is, if they’re old enough to read, they’re old enough to pack their own bags. Assuming your little ones are old enough, the most effective thing to do is give them some time frame to take complete responsibility for getting themselves ready, ask questions to help prompt them if you think they aren’t paying attention to something crucial, and most importantly, when things aren’t crucial (e.g. do they have the right uniform packed), letting them fail. Nothing teaches quite like experience. As you let go of the reigns a bit, here are some more ideas to guide you.
• Planning Starts the Night Before. Mornings are not the right time to teach your children how to pack themselves. You’re rushed, and they’re often bleary-eyed and grumpy. The ideal time to sit down with them, explain what you are trying to accomplish, and get them to start preparing for the next day is after homework but before TV time. That way you have time to ask them questions and offer un-stressed help in the initial stages. This is a process that will take time and spending time in the evenings helping them learn how to become responsible for themselves is time well spent.
• Explain as You Go. You need to develop a checklist with them and then go through the items. Don’t criticize or watch over the task being done. Accept that the task will not be done exactly the way you would do it but recognize that as long as it is accomplished and done on time, that it is okay. In the beginning, be prepared to patiently ask and answer a lot of questions! Why do emergency numbers need to be in the backpacks? Because you might need to call someone. Why does lunch have to be prepared? So that mom knows they are eating healthy and, besides, too much sugar will make them feel bad, Why do you keep asking about permission slips or projects that need to go with them? Because it’s important they do not miss out on something the rest of the class is doing. This is just a primer but you get the idea.
• Provide Feedback. Once the task has been completed, give constructive feedback to the person. As a guideline, tell your son or daughter five great things about the job for every one criticism. If after some time you notice they are consistently sloppy or forgetful, be patient but firm and make sure there are consequences for actions.


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Table of contents
Bluetooth is an industrial specification for wireless data transfer. Bluetooth connectivity is often found in high-end keyboards and mice. Bluetooth generally provide an operating range of up to 30 feet and is less prone to interference in comparison to RF technology.
DPI and FPS
DPI (dots per inch) and FPS (frames per second) are the number of counts in an inch of movement and the number of times the sensor reads the surface in a second respectively. These figures are measures of the amount of information recorded by the mouse's sensor. The greater the amount of information that is gathered, the more accurately and precisely the surface can be tracked. To detect movement, optical and laser mice use sensors to read beams of light as they are reflected from the tracking surface.
Currently 400 and 800 DPI optical mice as well as 800 DPI laser mice are very popular, but some high-end models are capable of 1000, 1600 or even 2000 DPI tracking speeds.
The Personal System/2 or PS/2 was the designation for IBM's second generation of personal computers. The PS/2 keyboard and mouse ports were introduced with it. PS/2 ports connect the keyboard and mouse to a computer and are usually color-coded on today's systems - purple for keyboards and green for mice. Most desktop motherboards still provide PS/2 ports, but an increasing number of keyboards and mice are using USB ports.
Radio Frequency (RF) is a wireless communication technology. Using RF technology allows keyboards and mice to computers without annoying cables.
The USB (Universal Serial Bus) port is a popular I/O interface used for connecting computers and peripherals or other devices. It is capable of supporting up to 127 daisy-chained peripheral devices simultaneously. The latest USB 2.0 specification can deliver 480Mbps data transfer bandwidth. In addition, USB provides plug-and-play capabilities to allow device changes while the computer is powered on. Today, many keyboard and mice use the USB interface.


During the next two weeks, you can help build a map of global light pollution, assisting scientists and astronomers as they monitor the loss of virgin night skies. You just have to look at the stars and write down what you see — or, more likely, what you don’t see.
Imagine if every time you needed to officially identify yourself you had to be sedated and knocked out cold. This might sound only slightly less stressful than checking through security at the airport, but for animals being tracked by wildlife authorities and researchers it’s a regularity that is not only stressful, but potentially harmful.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.


Henri MatisseFrench (Le Cateau-Cambrésis, France, 1869 - 1954, Nice, France)
Along with Pablo Picasso, Henri Matisse was one of the pillars of the Parisian avant-garde, whose formal innovations in painting would dominate much of modern art. Matisse initially worked in law, but discovered a passion for art when he began painting as an amateur. He went on to study traditional academic painting. In the early years of the twentieth century, however, he rejected the idea that painting had to imitate the appearance of nature. His characteristic innovations were the use of vibrant, arbitrary colors; bold, autonomous brushstrokes; and a flattening of spatial depth. This anti-naturalistic style inspired the critical name "fauves," or "wild beasts," for the group of painters around Matisse.
Ironically, Matisse often applied his thoroughly modern style to traditional subjects such as still lifes, landscapes, and portraits. Such works express a sense of timeless joy and stillness that runs counter to the frenetic, technologically inspired compositions of many of his contemporaries. Although primarily dedicated to painting, Matisse was also active as a sculptor and printmaker. In the 1940s, in failing health, he embarked on a well-known group of cut-paper collages.


It has been six years since the U.S. has had to worry about mad cow disease. With the recent confirmed case of the disease in a California bovine, the public is worried about food safety. Is there reason for concern?
Is our food safe?
Since 2006, the U.S. has had no positive tests for mad cow disease or bovine spongiform encephalopathy (BSE). This new case, found in California’s Central Valley, marks only the fourth occurrence ever in the U.S., out of 40,000 tests each year. The infected cow, however, never entered the human food chain, meaning that there is no risk to beef and/or dairy products, nor is there a risk for other countries who import U.S. beef.
Read about Oprah’s connection to mad cow disease >>
"The beef and dairy in the American food supply is safe..."
No risk to humans
In an effort to quell the rising public concern, the USDA has issued a statement regarding the recent case of mad cow disease. In part, Tom Vilsack, U.S. Agriculture Secretary, said, "The beef and dairy in the American food supply is safe and USDA remains confident in the health of U.S. cattle… USDA has no reason to believe that any other U.S. animals are currently affected, but we will remain vigilant and committed to the safeguards in place."
Read more about selecting organic foods >>
To further ease our minds, John Clifford, the U.S. Department of Agriculture’s chief veterinarian, said that this particular cow died of an atypical form of mad cow disease which was caused by a random mutation and not from contaminated feed, meaning that it was a chance occurrence.
Learn more about the benefits of grass-fed beef >>
There was a time when mad cow disease was rampant, but in recent years, the numbers have dropped drastically. In 2011, only 29 cases were reported worldwide, compared to over 37,000 cases in 1992. Cattle ranchers are actually touting this recent discovery as proof that the system is working as it should.
Still in the mood for beef? Cook the perfect tenderloin >>
More food news


Alice Walker usually puts herself into characters that she writes about in her stories. However, you don't understand this unless you know about her. Staring with this let us find out about who she is and where she came from. When recounting the life of Alice Walker, you find out that she was born to sharecroppers in Eatonton, Georgia in 1944 and was the baby of eight children. She lost one of her eyes when her brother shot her with a BB gun by accident. She was valedictorian of her class in high school and with that and receiving a scholarship; she went to Spelman, a college for black women, in Atlanta. She then transferred to Sarah Lawrence College in New York and during her time there went Africa as an exchange student. She received her Bachelor of Arts degree from Sarah Lawrence in 1965. She was active in the Civil Rights Movement of the 60's and as of the 90's she is still an involved activist. She started her own publishing company in 1984, Wild Tree Press. She is an acclaimed writer and has even received a Pulitzer Prize for the movie, The Color Purple. What is it about her that makes her works so meaningful and persuasive? What provoked her to write what she has?
One of her works, a short story called Everyday Use, is a story that she herself can be pictured in. During the opening of this story you find a woman with her two daughters. She and one of her daughters, Maggie, have just cleaned and beautified the yard of their new house. It is very comforting sitting under the Elm tree that is present and blocks the wind from going through the house. It is a place that you feel enveloped in comfort and love. Maggie and Dee, the other daughter are very different, and it is very apparent that mother, is not your everyday' woman. She, the mother, is "a larger woman that can kill and clean a hog as mercilessly as a man' (American Lit, p. 2470). She has no problems doing what needs to be done in order to feed and protect her... [continues]
Cite This Essay
(2005, 05). Instilled Heritage. StudyMode.com. Retrieved 05, 2005, from http://www.studymode.com/essays/Instilled-Heritage-57580.html
"Instilled Heritage" StudyMode.com. 05 2005. 05 2005 <http://www.studymode.com/essays/Instilled-Heritage-57580.html>.
"Instilled Heritage." StudyMode.com. 05, 2005. Accessed 05, 2005. http://www.studymode.com/essays/Instilled-Heritage-57580.html.


July 16, 2010
"Having HIV appears to be associated with a greater risk of death, even when the immune system is relatively robust and patients have not started treatment," according to a study published Friday in the Lancet, MedPage Today reports (Smith, 7/15).
Though the WHO recommends patients begin receiving antiretroviral therapy (ART) when their CD4 levels -- a measure of immune system response -- dip below 350, "[t]he researchers said their findings point to the need for continuing studies to examine the risks and benefits of starting antiretroviral therapy, or ART, for patients with high CD4 cell counts," HealthDay News reports.
"For this study, researchers examined data from 40,830 HIV patients, aged 20 to 59, in Europe and North America, who had at least one CD4 count greater than 350 cells per microliter while not taking ART. The patients were divided into four risk groups: men who have sex with men, heterosexuals, injection drug users, and those with other or unknown risk factors," the news service writes.
"The relatively low rate for men who have sex with men suggests that unmeasured confounders -- such as lifestyle and socioeconomic factors -- might play a role in the high rates for the other groups, the researchers said," MedPage Today continues (7/15).
However, when compared to patients with CD4 counts between 350 and 499, the death rate was 23 percent lower in patients with counts of 500-699 and 34 percent lower with patients with counts at or above 700, according to the Lancet study. "Because ART might reduce the risk of death in such patients, these findings support the need for continuing studies (such as the START trial and further exploration of existing observational databases) of the risks and benefits of starting ART at CD4 counts greater than 350 cells per ?L," the authors conclude (Study Group on Death Rates at High CD4 Count in Antiretroviral Naive Patients, 7/16).
However, the study authors "cautioned that the findings may not apply outside Europe and North America, where all of the patients were under care. ? They also noted that all of the patients were diagnosed early in the course of the disease, and their attitudes to healthcare might differ from those diagnosed later," MedPage Today adds (7/15).
Top Issues at AIDS 2010; Fauci on HIV Vaccine, Prevention; Funding Global HIV/AIDS Programs; HIV in The Middle East, North Africa
IRIN/PlusNews examines some of the "issues likely to top the list" during the International AIDS Conference-AIDS 2010, which kicks off July 18 in Vienna, Austria, including universal access to treatment, recent scientific developments in the area of HIV/AIDS research and the topic of treatment as prevention (7/15).
The Kaiser Family Foundation will provide webcasts of select sessions from AIDS 2010 starting with the Opening Session LIVE at 19:30 CEST/17:30 GMT/1:30 p.m. ET on Sunday, July 18.
Agence France-Presse features a conversation with Anthony Fauci, head of the National Institute for Allergy and Infectious Diseases (NIAID), who speaks of recent advances that scientists hope will bring them closer to the development of an HIV vaccine.
In the article, Fauci reflects on the results of the Thai HIV vaccine trial, which found an investigational HIV vaccine provided slight protection against HIV, and the recent discovery of three antibodies that protect against HIV in one individual. Fauci noted that while the two studies "have left scientists feeling 'much more confident that ultimately we will have a vaccine' against HIV/AIDS, although it was still impossible to say exactly when that would be," AFP writes.
Fauci also spoke of the importance of a continued emphasis on HIV prevention programs, including such things as male circumcision and syringe exchange programs. "Ways have to be found, too, to improve access to these preventive measures, especially in developing countries where only 20 percent of "populations who would benefit" actually have access to them, he added," the news service writes (Santini, 7/15).
In other news, Medecins Sans Frontieres (MSF) on Thursday said international donors need to maintain their commitments for global HIV/AIDS programs ahead of AIDS 2010, during which they pointed to their recent report that estimated the potential consequences of "'delayed, deferred, or denied'" global HIV/AIDS funding on patient populations worldwide, Reuters reports.
"The report suggested that far from cutting back on treatment projects in high-risk developing regions such as sub-Saharan Africa, donors should recognise that investing now in earlier treatment for more patients would pay off later," the news service writes (Kelland, 7/15).
"MSF's study showed that early and sustained treatment of HIV patients had born fruit in several regions, including Malawi's Thyolo district where the overall death rate dropped by a stunning 37 percent between 2000 and 2007, thanks to universal access to ARVs," AFP reports. "Where patients get treatment, 'there is an overall reduction of mortality in the community, there is also less tuberculosis and we start to see, where there is a high coverage of ARV, also a reduction in the number of new cases (of HIV/AIDS),' said [Mit] Philips," who authored the MSF report (7/15).
"In light of the financial crisis, donors may be tempted to walk away from their commitments to provide universal access to AIDS treatment," the report said, according to Reuters. "But these policies are short-sighted and fail to take into account long-term payoffs, including savings in economic terms, as well as increased quality of life and quality outcomes," Reuters continues.
The report also said the U.S. is "'flatlining' funding for AIDS treatment,'" the news service adds (Kelland, 7/15).
In related HIV/AIDS coverage, the National reports on the U.N. Development Program and UNAIDS' decision to form a commission to examine "whether legal structures criminalise certain types of high-risk behaviour and drive the disease underground" and what that might mean for the Middle East.
"Last month's U.N. conference in Dubai found many countries in the Middle East and North Africa fall 'well short' of providing universal treatment, with sufferers often subject to ill-treatment, social stigma and discrimination," the newspaper writes (Reinl, 7/15).
Meanwhile, the Economist looks at the travel restrictions people living with HIV/AIDS face throughout the world, including the Middle East. "In the past year, both China and America have lifted 20-odd-year bans stopping individuals with HIV from entering, but 51 countries still restrict movement in some form (be it entry to the country or a stay therein) based on a person's HIV status," the magazine writes. The magazine features a graphic demonstrating the countries that apply "the severest restrictions to HIV sufferers, including the denial of entry visas and even deportation" (7/15).
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Being referred for radiation treatment is an unfamiliar experience to most cancer patients. On these pages, we will explain radiation oncology to you and answer questions that most often exist for our patients. And we will also explain why you should feel remarkably confident in coming to URMC, the region’s leader in radiation oncology.
What is Radiation Oncology?
Radiation oncology is one of the three major cancer specialties in oncologic medicine. It uses energy from radiation beams, radio isotopes, or charged particles to target tumors and to eradicate cancer cells.
Radiation beams are usually generated in treatment machines, such as linear accelerators or high-energy CT scanners. Another type of radiation treatment uses radioisotopes, or radioactive materials. These are utilized in radiation implants and radioisotope-labeled molecules in the treatment of various cancers.
In addition to getting rid of cancer, radiation treatment is highly effective in reducing symptoms such as cancer-related pain. Radiation has also been used in the treatment of many benign (non-cancerous) conditions in both adults and children.
What Makes URMC Different?
At the James P. Wilmot Cancer Center, the Department of Radiation Oncology is an essential part of multidisciplinary care. In other words, a team of experts from surgery, medical oncology, radiation oncology, and many other disciplines will come together to evaluate and manage your cancer treatment. This is a unique approach to care and is considered the ideal model of cancer care.
The Department of Radiation Oncology provides state-of-the-art treatment technology to increase the curability of cancer while reducing side effects. Our comprehensive cancer care team includes physician radiation oncologists, radiation physicists, radiation therapists, dosimetrists, nurses, social workers, and nutritionists.
What Should I Expect as a Patient?
Your treatment will involve a team of healthcare providers from the Department of Radiation Oncology. Typically, a radiation oncologist will direct the radiation treatment process and plans. Your team will also include a secretary, a nurse, a nurse practitioner, a resident physician in training, radiation therapists who operate the treatment machines, and a radiation dosimetrist or physicist specializing in radiation treatment physical plans.
The department also offers assistance from social workers and nutritionists. Support groups for cancer patients are also available. These include disease-specific groups, age-specific groups, and many others.
A typical radiation treatment process begins with an initial consultation with your radiation oncologist. The treatment recommendation, indication, rationale, benefits, side effects, and potential risks will be explained to you. This is followed by a radiation simulation session, which takes approximately one hour. This simulation process ensures the accuracy of your treatment plan.
Your actual treatment will begin 7-14 days later. However, patients with cancer-related emergencies can begin their treatments sooner. Daily treatment visits may take 15 -30 minutes and generally last 1 to 8 weeks, depending on the diagnosis and the treatment plan. The stereotactic brain radiosurgery is generally completed in one session. The stereotactic body radiosurgery is generally completed in less than 10 sessions.
Your radiation oncologist, therapists, and the team nurse will be there for you every step of the way. They will help you assess treatment-related side effects, your progress, and tolerance.
What Technology do you Offer?
We offer state-of-the-art equipment for external beam radiation at all four of our treatment sites: Strong Memorial Hospital (SMH), Highland Hospital (HH), Cancer Center at Park Ridge (PR), and Sands Cancer Center.
- CT simulators (SMH, PR)
- Megavoltage CT (SMH)
- Cone-beam CT units (SMH)
- Linear accelerators with IMRT and IGRT capabilities (SMH, HH, PR, Sands)
- Novalis Radiosurgery (SMH)
- TomoTherapy (SMH)
- Brachytherapy (SMH, HH, PR)
- Prostate seed implants (SMH, HH, PR)
- GYN implants for gynecologic cancer (HH)
- Nucletron High Dose Rate Brachytherapy (HH)
- Liver radiation using Theraspheres (SMH)
- I-131 treatment for thyroid cancer (HH, PR)
- Radioactive mesh tumor bed boost for lung cancer (SMH)
- Total Body Irradiation (SMH)
- Accelerated partial breast radiotherapy using MammoSite or external beam (SMH, HH, PR, Sands)
How can I Learn More About my Disease or Condition?
Your cancer treatment team in the Department of Radiation Oncology will be your very best resource for learning more.
A radiation oncologist will evaluate your treatment process during your treatment course at a one-on-one session with you at least once a week. The nurse, nurse practitioner, physician's assistant, and resident physician on your team will also be valuable resources regarding education about your disease or condition.
In addition, the Wilmot Cancer Center has a patient and family resource center for those seeking additional information about specific cancers as well as information concerning radiation therapy. The center is located on the 1st floor of the Cancer Center.
If you are a patient and you need to speak to us right away, please call our Clinic Coordinator at (585) 275-4958.
Make an Appointment
If you would like to make an appointment or consult our physicians for a second opinion, please contact us at one of the following locations:
- Wilmot Cancer Center
- Highland Hospital
- Cancer Center at Park Ridge
- Sands Cancer Center


A new study in the Journal of the National Cancer Institute shows death rates from cancer steadily declined from 1994 to 1998. But the rates have since leveled off.
Lung cancer still remains the number one cancer killer in America. The American Cancer Society estimates that eight out of 10 lung cancer deaths are due to smoking.
Data from the Centers for Disease Control and Prevention shows Kentucky not only leads the way in percentage of smokers in the population, but also has the highest lung cancer death rates in the country.
The state health department says it will spend $4.8 million on tobacco control programs this year--an amount that still falls far short of the $25 million recommended by the CDC for the state. This puts Kentucky in 40th place overall for tobacco control spending.
Health officials say they are doing the best they can with the funds available for tobacco control programs.


The Molymod® biochemistry set for students can be used to make any number of simple organic molecules but in particular the set is designed to allow the user to make many important biological molecules including amino acids, peptides, polysaccharides, purines, pyrimidines, glycerides, and phospholipids. The set includes some hydrogen atoms with two holes allowing the depiction of hydrogen bonding. Atom parts are made of attractive solid plastic spheres. In this set they are available with from 1 - 4 holes in the usual angular orientations.
Contents of the Molymod® biochemistry molecular model set (for students)
The contents are contained within a sturdy plastic storage box (235 x 170 x 35 mm) and includes a brief instruction leaflet.
The Molymod® system is the original, unique, dual-scale system of high quality low-cost molecular models. These enormously popular sets are ideal for students but are also used by scientists all over the world.
Important notice: Molymod® atomic and molecular model products are scientific educational and visualization aids, and consequently are not suitable for children less than 10 years old.
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How does the law treat Mountaintop Removal? Laws at the state and federal level regulate mountaintop removal coal mining and its environmental impacts, require varying levels of public participation, and apply varying amounts of scrutiny in the permitting process. This section will explore the governmental institutions that exert influence over mountaintop removal coal mining, the laws that regulate it, and potential changes in the law. There is great dispute as to whether or not regulations and their enforcement sufficiently safe-guard the health, safety, and well-being of communities living near mountaintop removal sites and the surrounding environment, so both law as written and law as applied will be explored in this section.
National Environmental Protection Act
The National Environmental Protection Act was passed in 1970 in order to monitor the environmental impact of federal agency actions and decisions. The act created a Council on Environmental Policy, required environmental impact statements and a process to solicit public input to include environmental concerns in federal agency decision making.
In the case of mountaintop removal and valley fill permitting, coal companies prepare and submit an Environmental Impact Statements
(EIS) for each permit. In theory, these statements assess the potential impact of mining on the environment. The Army Corps of Engineers is empowered to issue Finding of no Significant Impact (FONSI) documents which supersede any concerns that may be present in the EIS by explaining why the Corps has concluded that there are no significant
environmental impacts resulting from the granting of a permit. In the past, this power has been used to streamline the permitting process, despite the obvious impacts of mountaintop removal mining.
Instances exist where permits were granted despite inadequate EIS statements, and then challenged in court. For example, as part of a settlement agreement from the Bragg vs Robertson (Civ. No. 2:98-0636 (S.D. W.V.)
the EPA, the Corps, the U.S. Interior Department's Fish & Wildlife Service and Office of Surface Mining, and the West Virginia Department of Environmental Protection (DEP), prepared an environmental impact statement (final EIS
) looking at the impacts of mountaintop mining and valley fills
More information is available in the Citizen's Guide to NEPA.
Clean Water Act
Congress passed the Clean Water Act (CWA) in 1972 with the intention of resolving the crisis of America's polluted waterways and wetlands. The CWA combines regulatory and non-regulatory tools in attempting to rid current water systems of pollutants, while attempting to stem the development of new polluted waterways and wetlands. In order to safeguard against the dumping of waste and pollutants into waterways, the Act forbids all dumping (except for specific agricultural uses) that is not approved by the Army Corps of Engineers.
Surface mines are required to obtain a National Pollutant Discharge Elimination System (NPDES) permit, which is regulated under the CWA. In West Virginia, the DEP has primacy of enforcement of the NPDES permits with EPA acting as the federal oversight body. These permits cover all pollutants discharged off the site and into the waters of the United States, restricting effluent limits and requiring the site operator to explain in the mining plan how it will meet those limits and treat what's running off the site, among other requirements.
Valley Fill, or 404, Permits
If a mining plan calls for valley fills, a 404 permit must be obtained, which is an exemption to Subsection 404 of the CWA which allows the Corps to issue variances to fill in an intermittent or perennial stream. EPA follows the United States Geological Survey's definitions for streams: an intermittent stream holds water during wet portions of the year and a perennial stream holds water throughout the year.
The Corps does not have authority over water quality, that's the jurisdiction of the EPA who oversees this permit. However, since anything that interferes with the flow of the water of the United States is regulated by the Corps, the Corps administers valley fills. This is the only part of surface mine permitting where the state does not have primacy of enforcement.
"The thing that's ironic here is that the fill rule was originally developed for developers seeking to build, and this was intended for very small projects, primarily for filling in wetlands for building things like subdivisions and shopping malls," Sludge Safety Project staffer Mathew Louis-Rosenberg said. "So, the division that handles these permits is the Division of Wetlands. Within that, the standards that are developed, that are currently used to determine the environmental impact of a fill, were developed for wetland ecosystems.
"We can't allow them to continue to keep issuing permits. Look at what they're using to evaluate them. It's an ecosystem that bears no resemblance to what we're evaluating." The people who authored the guidelines testified to Joe Lovett, a West Virginia lawyer who's only tried cases aimed at ending mountaintop removal, that the methodology they developed was not appropriate for this ecosystem. "The people who literally wrote the book they use to decide whether they should issue a permit, said it's inappropriate," Louis-Rosenberg said.
There's two types of valley fill permits: individual and Nationwide 21. Large sites are supposed to obtain an individual permit, which carries a more stringent set of regulations requiring more data and proof that the project will not have an adverse impact on the environment. However, Nationwide 21 allows the Corps to issue a blanket permit for small things and, unlike the individual permits, does not require a public hearing.
Coal companies saw the value in nationwide permits, and would often break up large valley fills into smaller pieces in their permit applications in order to avoid the regulatory oversight of an
Listen to Ernie Thompson, resident of Horse Creek and former mine inspector, talk about the changes in law regarding valley fills.
individual permit. In this way, many valley fills were created when a nationwide permit was granted and residents did not notice until dumping began. Beginning with a court victory for advocates against mountaintop removal in 2007, Nationwide 21 permits were declared in violation of the Clean Water Act. This ruling remained in effect until the Fourth Circuit Court overturned it in early 2009.
Surface Mining Control and Reclamation Act (SMCRA)
On February 16th, 1972, a coal slurry impoundment ruptured in Buffalo Creek, W.Va. The rushing tidal wave of sludge killed over 120 people and left many thousands homeless, yet several days before the rupture a federal inspector had found the dam site in "satisfactory" safety. The dangers of strip mining had long been of concern to coalfield residents.
The increased mechanization of strip mining that left many union mining jobs and the encroaching growth of strip mines combined to spark a powerful grassroots movement to abolish strip mining. The tragedy of the Buffalo Creek Flood stoked these flames and five years later, in response to the growing political pressure from Southern Democrats and coalfield residents, Jimmy Carter signed the Surface Mining Control and Reclamation Act in 1977.
It did not abolish strip mining, instead stating that its primary goal was to "establish a nationwide program to protect society and the environment from the adverse effects of surface coal mining operations." To do so, it created the Office of Surface Mining in the Department of the Interior and the regulations for them to enforce. The surface mines constructed before SMCRA are often referred to as "pre-law," while those after are called "post-law."
The SMCRA permit is the whole mining plan, top to bottom, including the blasting plan. The DEP administers SMCRA permits but, unlike the NPDES permits, the Interior Department's Office of Surface Mining and Reclamation maintains oversight. The DEP's Office of Explosives and Blasting also approves the blasting plan within the SMCRA permit. A typical Environmental Impact Statement is also required here, "but they usually don't get filled out," Louis-Rosenberg said.
SMCRA requires that "all surface coal mining operations back-fill, compact... and grade in order to restore the approximate original contour of the land with all high-walls, spoil piles and depressions eliminated." However, the WVDEP regularly grants exceptions to the Approximate Original Contour (AOC) rule. This despite one of the act's goals: to "assure that surface mining operations are not conducted where reclamation as required by this Act is not feasible."
Since 1977, the following language was added to SMCRA, weakening this goal:
In cases where an industrial, commercial, agricultural, residential or public facility (including recreational facilities) use is proposed or the postmining use of the affected land, the regulatory authority may grant a permit for a surface mining operation of the nature described....after consultation with the appropriate land use planning agencies, if any, the proposed post mining land use is deemed to constitute an equal or better economic use of the affected land as compared to pre mining use.
This clause allows coal companies to not restore a site's AOC, as long as it is put to a better economic or social use than it was before. Under this clause, prisons and a golf course have been constructed on mountaintop removal sites. One such prison has earned the name Sink-Sink because it does just that. The mountains, and the ecosystems they support, have an intrinsic cultural value to the residents of the Coal River Valley that cannot be measured in monetary terms, and yet under SMCRA the economic value of the land supersedes all others.
Mining Safety and Health Administration Permit
The federal Mining Safety and Health Administration oversees the regulatory structure of the mines. All mines have to pass muster on the safety of operating the mine and this is all detailed in the MSHA plan the coal companies must file. Part of MSHA's responsibility is approval and inspection of coal slurry
dams. MSHA focuses on the safety aspect of the structures, not their environmental impacts.


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BioMed Central publishes over 200 peer-reviewed open access journals.
Indexes journals in a variety of subjects, including biology, chemistry, and environmental science. Many full-text articles are available.
AGRICOLA (AGRICultural OnLine Access) serves as the catalog and index to the collections of the National Agricultural Library. The records describe publications and resources encompassing all aspects of agriculture and allied disciplines, including animal and veterinary sciences, entomology, plant sciences, forestry, aquaculture and fisheries, farming and farming systems, agricultural economics, extension and education, food and human nutrition, and earth and environmental sciences.
Provides fulltext access to core scholarly journals in the Arts and Sciences
This collection of electronic books covers topics related to environmental science, including environmental chemistry, ecology, environmental toxicology, forestry, sustainability, and more.
GREENR (Global Reference on the Environment, Energy, and Natural Resources) is a database that offers content on the development of emerging green technologies and discusses issues on the environment, sustainability and more.
Reference QH540.4 .E515 2008
This is a free, fully searchable collection of articles written by scholars, professionals, educators, and other experts. The articles are written in non-technical language and will be useful to students, educators, scholars, professionals, as well as to the general public.
Reference QH360.2.O83 2002
Reference QR9.E53 2000
Reference QL7.G7813 2003
Reference QR358 .E53 1999
This two volume encyclopedia describes the most famous scientific concepts, principles, laws, and theories in astronomy, biology, chemistry, geology, mathematics, medicine, meteorology, and physics.
This encyclopedia considers both the professional ethics of science and technology, and the social, ethical, and political issues raised by science and technology.
This encyclopedia covers a wealth of topics on the ethics of health professions, animal research, population control and the environment.


When spraying pesticides, don't let others get your drift.
"It is bad enough when your drift damages your crops, your lawn or your garden. But when the damage is to your neighbor's field or flowerbeds, then you've got a real problem," says Erdal Ozkan, an Ohio State University Extension agricultural engineer.
Spray drift is one of the more serious problems pesticide applicators have to deal with. Three-fourths of the agriculture-related complaints investigated by the Ohio Department of Agriculture in 2003 involved drift.
"This shows the seriousness of the problem," Ozkan says. "Drift will be even a bigger problem in the future since there is an increase in acreage of genetically modified crops and use of non-selective herbicides for weed control. Even a small amount of these non-selective herbicides can cause serious damage on the crop nearby that is not genetically modified."
Drift is the movement of a pesticide through air, during or after application, to a site other than the intended site of application. It not only wastes expensive pesticides and damages non-target crops nearby, but also poses a serious health risk to people living in areas where drift is occurring.
"Eliminating drift completely is impossible," Ozkan says. "However, it can be reduced to a minimum if chemicals are applied with good judgment and proper selection and operation of application equipment."
Major factors influencing drift include spray characteristics, equipment/application techniques, weather conditions and operator skill and care.
"Conscientious sprayer operators rarely get into drift problems. They understand the factors that influence drift and do everything possible to avoid them," Ozkan said.
Spraying under excessive wind conditions is the most common factor affecting drift. "The best thing to do is not to spray under windy conditions. If you don't already have one, get yourself a reliable wind speed meter as soon as possible. Only then can you find out how high the wind speed is," Ozkan says.
After wind speed, spray droplet size is the most important factor affecting drift. Research has shown that there is a rapid decrease in the drift potential of droplets whose diameters are greater than approximately 200 microns – or about twice the thickness of human hair.
"If operators of sprayers pay attention to wind direction and velocity, and have knowledge of droplet sizes produced by different nozzles, drift can be minimized," Ozkan says. "The ideal situation is to spray droplets that are all the same size, and larger than 200 microns. Unfortunately with the nozzles we use today, this is not on option. They produce droplets varying from just a few microns to more than 1,000 microns. The goal is to choose and operate nozzles that produce relatively fewer of the drift-prone droplets."
Using low-drift nozzles is one of the many options available to growers to reduce drift.
Following are other drift-reduction strategies to keep drift under control:
- Use nozzles that produce coarser droplets when applying pesticides on targets that do not require small, uniformly distributed droplets, such as systemic products, preplant soil incorporated applications and fertilizer applications.
- Keep spray volume up and use nozzles with larger orifices.
- Follow recent changes in equipment and technology, such as shields and air-assisted and electrostatic sprayers that are developed for drift reduction in mind.
- Keep the boom closer to the spray target. Nozzles with a wider spray angle will allow you to do that.
- Keep spray pressure down and make sure pressure gauges are accurate.
- Follow label recommendations to avoid drift with highly volatile pesticides.
- If you are not using low-drift nozzles, try adding Drift Retardant Adjuvants into your spray mixture.
- Avoid spraying on extremely hot, dry and windy days, especially if sensitive vegetation is nearby. Try spraying during mornings and late afternoons. Although it may not be practical, from the drift reduction perspective, the best time to spray is at night.
- Avoid spraying near sensitive crops that are downwind. Leave a buffer strip of 50-100 feet, and spray the strip later when the wind shifts.
"Good judgment can mean the difference between an efficient, economical application, or one that results in drift, damaging non-target crops and creating environmental pollution," Ozkan says. "The goal of a conscientious pesticide applicator should be to eliminate off-target movement of pesticides, no matter how small it may be."


concept. The basic idea is that the human mind
can keep track of about seven
at once, or can differentiate between seven or so
different (but similar) things.
The phrase comes from the title of a 1956 paper by Harvard professor George
A. Miller titled, The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information, which begins:
My problem is that I have been persecuted by an integer. For seven years this number has followed me around, has intruded in my most private data, and has assaulted me from the pages of our most public journals. This number assumes a variety of disguises, being sometimes a little larger and sometimes a little smaller than usual, but never changing so much as to be unrecognizable. The persistence with which this number plagues me is far more than a random accident. There is, to quote a famous senator, a design behind it, some pattern governing its appearances. Either there really is something unusual about the number or else I am suffering from delusions of persecution.
Miller goes on to present data from a number of
experiments which support the idea
(by arriving at the number seven). Topics of the
experiments he reviewed included, "span of immediate
memory", "capacity for absolute judgements of the position of a dot
on a square", and (my favorite) "capacity for absolute judgements of saltiness


Tuesday, December 4, 2012
Today in History - Tuesday, Dec. 4, 2012
Today is Tuesday, Dec. 4, the 339th day of 2012. There are 27 days left in the year.
Today's Highlight in History:
On Dec. 4, 1619, a group of settlers from Bristol, England, arrived at Berkeley Hundred in present-day Charles City County, Va., where they held a service thanking God for their safe arrival. (Some suggest this was the true first Thanksgiving in America, ahead of the Pilgrims' arrival in Massachusetts.)
On this date:
In 1619, settlers from Bristol, England, arrived at Berkeley Hundred in present-day Charles City County, Va.
In 1783, Gen. George Washington bade farewell to his Continental Army officers at Fraunces Tavern in New York.
In 1816, James Monroe of Virginia was elected the fifth president of the United States.
In 1912, Medal of Honor recipient Gregory "Pappy" Boyington, the Marine Corps pilot who led the "Black Sheep Squadron" during World War II, was born in Coeur d'Alene, Idaho.
In 1918, President Woodrow Wilson left Washington on a trip to France to attend the Versailles (vehr-SY') Peace Conference.
In 1942, U.S. bombers struck the Italian mainland for the first time in World War II. President Franklin D. Roosevelt ordered the dismantling of the Works Progress Administration, which had been created to provide jobs during the Depression.
In 1965, the United States launched Gemini 7 with Air Force Lt. Col. Frank Borman and Navy Cmdr. James A. Lovell aboard.
In 1978, San Francisco got its first female mayor as City Supervisor Dianne Feinstein (FYN'-styn) was named to replace the assassinated George Moscone (mahs-KOH'-nee).
In 1984, a five-day hijack drama began as four armed men seized a Kuwaiti airliner en route to Pakistan and forced it to land in Tehran, where the hijackers killed American passenger Charles Hegna.
In 1991, Associated Press correspondent Terry Anderson, the longest held of the Western hostages in Lebanon, was released after nearly seven years in captivity. Pan American World Airways ceased operations.
In 1992, President George H.W. Bush ordered American troops to lead a mercy mission to Somalia, threatening military action against warlords and gangs who were blocking food for starving millions.
In 1996, the Mars Pathfinder lifted off from Cape Canaveral and began speeding toward Mars on a 310 million-mile odyssey. (It arrived on Mars in July 1997.)
Ten years ago: United Airlines lost its bid for $1.8 billion in federal loan guarantees, a major setback to the nation's second-largest air carrier in its efforts to avoid bankruptcy. Supreme Court justices heard arguments on whether federal laws intended to combat organized crime and corruption could be used against anti-abortion demonstrators. (The Court later ruled that such laws were improperly used to punish abortion opponents.)
Five years ago: Defending his credibility, President George W. Bush said Iran was dangerous and needed to be squeezed by international pressure despite a U.S. intelligence finding that Tehran had halted its nuclear weapons program four years earlier. The intelligence report on Iran figured in a Democratic debate on National Public Radio as rivals assailed front-runner Hillary Rodham Clinton for voting in favor of a Senate resolution designating Iran's Revolutionary Guard a terrorist organization. Pimp C (Chad Butler), a rapper with the Texas hip-hop group Underground Kingz, was found dead in a hotel room in Los Angeles; he was 33.
One year ago: Prime Minister Vladimir Putin's party hung onto its majority in Russia's parliamentary election, but faced accusations from opponents of rigging the vote. Rafael Nadal recovered from a terrible start and beat Juan Martin del Potro of Argentina 1-6, 6-4, 6-1, 7-6 (0) to give Spain its fifth Davis Cup title. After going more than two years and 26 tournaments without a victory, Tiger Woods won the Chevron World Challenge. Former Hewlett-Packard chairwoman Patricia Dunn, 58, died in Orinda, Calif.
Today's Birthdays: Actress-singer Deanna Durbin is 91. Game show host Wink Martindale is 79. Pop singer Freddy Cannon is 76. Actor-producer Max Baer Jr. is 75. Actress Gemma Jones is 70. Rock musician Bob Mosley (Moby Grape) is 70. Singer-musician Chris Hillman is 68. Musician Terry Woods (The Pogues) is 65. Rock singer Southside Johnny Lyon is 64. Actor Jeff Bridges is 63. Rock musician Gary Rossington (Lynyrd Skynyrd; the Rossington Collins Band) is 61. Actress Patricia Wettig is 61. Actor Tony Todd is 58. Jazz singer Cassandra Wilson is 57. Country musician Brian Prout (Diamond Rio) is 57. Rock musician Bob Griffin (The BoDeans) is 53. Rock singer Vinnie Dombroski (Sponge) is 50. Actress Marisa Tomei is 48. Actress Chelsea Noble is 48. Actor-comedian Fred Armisen is 46. Rapper Jay-Z is 43. Actor Kevin Sussman is 42. Actress-model Tyra Banks is 39. Country singer Lila McCann is 31. Actress Lindsay Felton is 28. Actor Orlando Brown is 25.
Thought for Today: "Many are called but few get up." — Oliver Herford, American author (1863-1935).


Department of Energy
- Land is essential for all types of economic activity - every business has a footprint.
- At the height of the 2006 real estate boom, land in the US is estimated to have been worth more than $17 trillion.
- Research presented by @AEI’s Stephen Oliner suggests that land is indeed a high-risk investment.
Land is essential for all types of economic activity. Every business — whether it’s General Motors or the corner grocery store — has a footprint. The same is true for the homes and apartments in which people live.
Land also constitutes a major part of wealth. At the height of the real estate boom in 2006, land in the United States (excluding farmland and land held by the government) is estimated to have been worth more than $17 trillion. This figure represents about 40 percent of the value of commercial real estate and housing in the United States.1 Of course, much of that wealth dissolved over the next few years as real estate markets crashed. The new research presented in this Letter documents the huge swing in land value over the recent cycle, showing that land is indeed a high-risk investment.
Read the full text of the letter here.


At a Glance
Why Get Tested?
To determine lithium levels in the blood in order to maintain a therapeutic level or to detect lithium toxicity
When to Get Tested?
When beginning treatment with lithium as the dose is adjusted to achieve therapeutic blood levels; at regular intervals to monitor lithium levels; as needed to detect low or toxic concentrations
A blood sample drawn from a vein in your arm
Test Preparation Needed?
The Test Sample
What is being tested?
This test measures the amount of lithium in the blood. Lithium is one of the most well-established and widely-used drugs prescribed in the treatment of bipolar disorder. Bipolar disorder is a mental condition that is characterized by alternating periods of depression and mania. These periods may be as short as a few days or weeks or may be months or years long. During a depressive episode, those affected may feel sad, hopeless, worthless, and lose interest in daily activities. They may be fatigued but have trouble sleeping, experience weight loss or gain, have difficulty concentrating, and have thoughts of suicide. During a manic episode, those affected may be euphoric, irritable, have high energy and grandiose ideas, use poor judgment, and participate in risky behaviors. Sometimes affected people will have mixed episodes with aspects of both mania and depression. Bipolar disorder can affect both adults and children.
Lithium is prescribed to even out the moods of a person with bipolar disorder; it is often called a "mood stabilizer" and is sometimes prescribed for people with depression who are not responding well to other medications. It is a relatively slow-acting drug and it may take several weeks to months for lithium to affect a person's mood. Dosages of the drug are adjusted until a steady concentration in the blood that is within therapeutic range is reached. The actual amount of drug that it will take to reach this steady state will vary from person to person and may be affected by a person's age, general state of health, and other medications that they are taking.
Lithium levels are monitored on a regular basis because blood levels must be maintained within a narrow therapeutic range. Too little and the medication will not be effective; too much and symptoms associated with lithium toxicity may develop, such as nausea, vomiting, diarrhea, confusion, and tremors. Extremely high levels can lead to stupor, seizures, and can be fatal.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed. However, timing of the sample collection may affect results. Generally, lithium blood levels are performed 12-18 hours after the last dose (also known as a "trough" level). Tell the laboratorian who is drawing your blood when you took your last dose so that the results can be interpreted correctly.
Ask a Laboratory Scientist
This form enables you to ask specific questions about your tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. If your questions are not related to your lab tests, please submit them via our Contact Us form. Thank you.
* indicates a required field
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pp 1271-1272.
Harrison's Principles of Internal Medicine. 16th ed. Kasper D, Braunwald E, Fauci A, Hauser S, Longo D, Jameson JL, eds. McGraw-Hill, 2005 Pg 2557.
(Updated March 24, 2009) Lee D, Gupta M. Toxicity, Lithium from Medscape. Available online at http://emedicine.medscape.com/article/815523-overview through http://emedicine.medscape.com. Accessed September 2009.
(January 15, 2009) MedlinePlus Medical Encyclopedia. Bipolar Disorder. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000926.htm. Accessed September 2009.
(January 4, 2009) Mayo Clinic. Bipolar Disorder. Available online at http://www.mayoclinic.com/health/bipolar-disorder/DS00356 through http://www.mayoclinic.com. Accessed September 2009.
National Alliance on Mental Illness. Medications, Lithium. Available online through http://www.nami.org. Accessed September 2009.
(Jan 14, 2009) Lloyd A. Netdoctor: Lithium. Available online at http://www.netdoctor.co.uk/diseases/depression/lithium_000290.htm through http://www.netdoctor.co.uk. Accessed September 2009.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 1121.
Spearing, M. Updated (2006 February 17,Updated). Bipolar Disorder. NIMH [On-line information]. Available online at http://www.nimh.nih.gov/publicat/bipolar.cfm#bp6 through http://www.nimh.nih.gov.
Goldberg, J. and Citrome, L. (2005 February). Latest therapies for bipolar disorder, Looking beyond lithium. Postgraduate Medicine online v 117 (2) [On-line journal]. Available online at http://www.postgradmed.com/issues/2005/02_05/goldberg.htm through http://www.postgradmed.com.
Geddes, J. et. al. (2004 February). Long-Term Lithium Therapy for Bipolar Disorder: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Psychiatry 161:217-222 [On-line journal]. Available online at http://ajp.psychiatryonline.org/cgi/content/full/161/2/217 through http://ajp.psychiatryonline.org.
Newport, D. J. et. al. (2005 November). Lithium Placental Passage and Obstetrical Outcome: Implications for Clinical Management During Late Pregnancy. American Journal of Psychiatry 162:2162-2170 [on-line abstract]. Available online at http://ajp.psychiatryonline.org/cgi/content/abstract/162/11/2162 through http://ajp.psychiatryonline.org.
Schapiro, N. (2005). Bipolar Disorders in Children and Adolescents. Medscape from J Pediatr Health Care. 2005; 19 (3): 131-141 [On-line information]. Available online at http://www.medscape.com/viewarticle/504584_1 through http://www.medscape.com.
Menon, L. (2005 August, Updated). Lithium. National Alliance for the Mentally Ill [On-line information]. Available online through http://www.nami.org.
Walling, A. (2005 January 1). Evidence-Based Guidelines for Bipolar Disorder Therapy. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20050101/tips/19.html through http://www.aafp.org.


Since the human body has no mechanism to excrete excess iron, it is probably best to refrain from consuming blood-based (heme) iron and taking iron supplements unless prescribed (for example, for pregnant women who are demonstrably anemic). This is because iron pills have been linked to birth complications such as preterm birth and maternal hypertension. Presumably because of iron’s pro-oxidant qualities, it can be a double-edged sword; lowering the iron level of cancer patients has been associated with dropping death rates. The absorption of plant-based (non-heme) iron can be regulated by the body, though, making dark green leafy veggies and legumes such as lentils preferable sources, especially since food is a package deal.
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What is OPEC?
OPEC is an acronym for Organization of the Petroleum Exporting Countries. OPEC was formed in 1960 in Baghdad, Iraq with five founding member countries. Currently OPEC is a cartel composed of 11
oil producing countries. Current member countries include: Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela. OPEC's stated purpose is said to serve three main functions:
- Help stabilize world oil prices
- Ensure oil producers achieve a reasonable rate of return on production
- Ensure a stable supply of crude oil for consumer use. OPEC has a current goal of $27 US per barrel of oil.
How much crude oil do the OPEC countries produce?
Collectively these countries hold approximately 77% of known world crude oil reserves.
In terms of daily crude oil production OPEC countries currently produce about 41% (24.2 million barrels per day) of the world's crude oil. The oil exported by the OPEC countries accounts for 55% of all oil traded internationally. OPEC countries also represent about 15% of
total world natural gas production.
How does OPEC set oil prices?
OPEC does not "set" oil prices. OPEC manipulates the free market price of crude oil by setting caps on the oil production of its member countries. Twice each year, ministers from each OPEC country meet
in Vienna, Austria to review the status of the international oil market and to forecast the future oil demands in order to agree upon an appropriate crude oil production level.