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Basic Physics of Nuclear Medicine/Computers in Nuclear Medicine

Introduction
This is a developing chapter for a Wikibook entitled Basics Physics of Nuclear Medicine.

Computers are widely used in almost all areas of Nuclear Medicine today. The main application for our purposes is imaging acquisition and processing. This chapter outlines the design of a generalised digital image processor and gives a brief introduction to digital imaging.

Before considering these topics, some general comments are required about the form in which information is handled by computers as well as the technology which underpins the development of computers so that a context can be placed on our discussion.

Binary Representation
Virtually all computers in use today are based on the manipulation of information which is coded in the form of binary numbers. A binary number can have only one of two values, i.e. 0 or 1, and these numbers are referred to as binary digits – or bits, to use computer jargon. When a piece of information is represented as a sequence of bits, the sequence is referred to as a word; and when the sequence contains eight bits, the word is referred to as a byte – the byte being commonly used today as the basic unit for expressing amounts of binary-coded information. In addition, large volumes of coded information are generally expressed in terms of kilobytes, megabytes etc. It is important to note that the meanings of these prefixes can differ slightly from their conventional meanings because of the binary nature of the information coding. As a result, kilo in computer jargon can represent 1024 units – 1024 (or 210) being the nearest power of 2 to one thousand. Thus, 1 kbyte can refer to 1024 bytes of information and 1 Mbyte can represent 1024 times 1024 bytes. To add a bit of confusion here, some hardware manufacturers refer to a megabyte as 1 million bytes and a gigabyte as a 1,000 million bytes. Its not a simple world, it seems!

Binary coding of image information is needed in order to store images in a computer. Most imaging devices used in medicine however generate information which can assume a continuous range of values between preset limits, i.e. the information is in analogue form. It is therefore necessary to convert this analogue information into the discrete form required for binary coding when images are input to a computer. This is commonly achieved using an electronic device called Analogue-to-Digital Converter (ADC). Furthermore, since many display and photographic devices used in medicine are designed for handling images in analogue format, it is necessary to reconvert the discrete, binary data when outputting images from a computer using a Digital-to-Analogue Converter (DAC).

Development of Modern Computers
The development of modern computers has been almost totally dependent on major developments in material science and digital electronics which have occurred over the last thirty years or so. These developments have allowed highly complex electronic circuitry to be compressed into small plastic packages called integrated circuits. These packages contain tiny pieces of silicon (or other semiconductor material) which have been specially manufactured to perform complex electronic processes. The pieces of silicon are generally referred to as silicon chips. Within the circuitry of a chip, a relatively high electronic voltage can be used to represent the digit '1' and a relatively low voltage can be used to represent the binary digit '0'. Thus the circuitry can be used to manipulate information which is coded in the form of binary numbers.

An important feature of these electronic components is the very high speed at which the two voltage levels can be changed in different parts of the circuitry. This results in the ability of the computer to rapidly manipulate the binary information. Furthermore, the tiny size of modern integrated circuits has allowed the manufacture of computers which are very small physically and which do not generate excessive amounts of heat – previous generations of computers having occupied whole rooms, which required cooling because they were built using larger electronic components such as valves and transistors. Thus modern computers are capable of being mounted on a desk in an environment which does not require air-conditioning. In addition, the ability to manufacture integrated circuits using mass production methods has given rise to enormous decreases in costs – which has contributed to the phenomenal explosion of this technology in recent years.

Before beginning, it is worth noting that the information in this chapter is likely to change by the time the chapter is read, given the ongoing, rapid developments in this field. The treatment here is therefore focused on general concepts – and you should note that current technologies and techniques may well differ from those described here. In addition, note that mention of any hardware or software product in this chapter does in no way intend support for such a product and its use in this discussion is purely for illustrative purposes.

Hardware
The figure below shows a block diagram of the major hardware components of a general-purpose computer. It shows that a computer consists of a central communication pathway, called a bus, to which dedicated electronic components are connected. Each of these components is briefly described below.

Central Processing Unit (CPU) This component is based, in many modern computers, on an integrated circuit called a microprocessor. Its function is to act as the brains of the computer where instructions are interpreted and executed, and where data is manipulated. The CPU typically contains two sub-components – the Control Unit (CU) and the Arithmetic/Logic Unit (ALU).

The Control Unit is used for the interpretation of instructions which are contained in computer programs as well as the execution of such instructions. These instructions might be used, for example, to send information to other components of the computer and to control the operation of these other components. The ALU is primarily used for data manipulation using mathematical techniques – for example, the addition or multiplication of two numbers.

Important features of individual microprocessors include word length, architecture, programming flexibility and speed. An indicator of speed is the clock rate and values for common microprocessors are given in the following table. Note that the clock rate on its own does not provide a complete indication of computer performance since the specifications of other components must also be considered.

Main Memory This component typically consists of a large number of integrated circuits which are used for the storage of information which is currently required by the computer user. The circuitry is generally of two types – Random Access Memory (RAM) and Read Only Memory (ROM). RAM is used for the short-term storage of information. It is a volatile form of memory since its information contents are lost when the electric power to the computer is switched off. Its contents can also be rapidly erased – and rapidly filled again with new information. ROM, on the other hand, is non-volatile and is used for the permanent storage of information which is required for basic aspects of the computer's operation.

Secondary Memory This component is used for the storage of information in permanent or erasable form for longer-term purposes, i.e. for information which is not currently required by the user but which may be of use at some later stage. There are various types of devices used for secondary memory and some of their features are summarised in the following table. RAM is also included in the table for comparison.

The type of technology used is generally based on magnetic materials – similar to those used for sound recording in hi-fi systems. Here, the information is stored by controlling the local magnetism at different points of the storage material and is retrieved by detecting this magnetism. The local magnetism, as might be expected, can assume one of two magnetic states because of the binary nature of the coded information. Materials such as plastic tapes and disks, which have been coated with a layer of magnetic material, are used. Magnetic tapes generally consist of open reels or enclosed cassettes, while magnetic disks generally consist of flexible (or floppy) disks or disks made from a harder plastic. Floppy disks, like magnetic tapes, can be removed from the computer system and are used for external storage of information. Memory sticks can also be used for this purpose. They also allow the capability of transporting information between computers. Hard disks, on the other hand, are usually fixed inside the computer and thus cannot be easily removed – although removable versions are also in use, e.g. the iPod and similar devices.

Recent developments in our understanding of magnetic and optical characteristics of materials has led to the production of the so-called optical disk – which is similar to the compact disk (CD) used in hi-fi systems. Three general types of optical disk are available: those containing programs supplied by software companies (as in the CD-ROM disk), those which can be written to once by the user (as in the CD-R disk) and those which are erasable (as in the CD-RW disk and the magneto-optical disk). The Digital Versatile Disk (DVD) is a likely successor to the CD-ROM – the first generation having a storage capacity of 4,700 Mbyte (4.7 Gbyte) and the second generation an expected 17,000 Mbyte (17 Gbyte).

A general difference between tape and disk as a secondary storage medium results from the sequential nature of the access to information stored on tape, in contrast to the random nature of the access provided by disks. As a result, disk-based media are typically faster for information storage/retrieval than those based on tape. A number of modern designs of secondary memory are therefore based on hard magnetic disks for routine information storage, with floppy disks used for back-up storage of small volumes of information and optical disks for back-up storage of larger volumes of information.

Input/Output Devices These components are used for user-control of the computer and generally consist of a keyboard, display device and printer. A wide range of technologies are used here – the details however are beyond the scope of this chapter. These components also include devices such as the mouse, joystick and trackpad, which are used to enhance user-interaction with the computer.

Computer Bus This consists of a communication pathway for the components of the computer – its function being somewhat analogous to that of the central nervous system. The types of information communicated along the bus include that which specifies data and control instructions as well as the memory addresses where information is to be stored/retrieved. As might be anticipated, the speed at which a computer operates is dependent on the speed at which this communication link works. This speed must be compatible with that of other components, such as the CPU and main memory.

Software
There is more to computer technology than just the electronic hardware. In order for the assembly of electronic components to operate, information in the form of data and computer instructions is required. This information is generally referred to as software. Computer instructions are generally contained within computer programs.

Categories of computer program include:
 * Operating systems – which are used for operating the computer and for managing various resources of the computer. Examples of operating systems are Windows, MacOS X, Linux and UNIX;
 * Application packages – which are for the use of routine users of the computer. These packages include programs which are used for word-processing (e.g. MS Word), spreadsheets (e.g. MS Excel), databases (e.g. FileMaker Pro), graphics (e.g. Adobe Illustrator) and digital image processing (including software used for operating specific medical imaging scanners);
 * Programming packages – which are used for writing programs. Examples of common computer languages which are used for writing programs are C (and its many variants) and Java.  A number of additional pieces of software are required in order for such programs to be written.  These include:
 * An Editor for writing the text of the program into the computer (which is similar to programs used for word-processing);
 * A Library of subroutines – which are small programs for operating specific, common functions;
 * A Linker which is used to link the user-written program to the subroutine library;
 * A Compiler or Interpreter for translating user-written programs into a form which can be directly understood by the computer, i.e. it is used to code the instructions in digital format.

 * These programming functions and more are combined in packages which generate an Integrated Development Environment (IDE), a good example being Xcode.

Digital Image Processor
Computers used for digital image processing generally consist of a number of specialised components in addition to those used in a general-purpose computer. These specialised components are required because of the very large amount of information contained in images and the consequent need for high capacity storage media as well as very high speed communication and data manipulation capabilities. Digital image processing involves both the manipulation of image data and the analysis of such information. An example of image manipulation is the computer enhancement of images so that subtle features are displayed with greater clarity. An example of image analysis is the extraction of indices which express some functional aspect of an anatomical region under investigation. Most medical imaging systems provide extensive image manipulation capabilities with a limited range of image analysis features. Systems for processing nuclear medicine images (including SPECT and PET) also provide extensive data analysis capabilities. This situation arises because of the functional, in contrast to an anatomical, emphasis in nuclear medicine.

A generalised digital image processor is shown in the following figure. The shaded components at the bottom of the diagram are those of a general-purpose computer which have been described above. The digital image processing components are those which are connected to the image data bus. Each of these additional components is briefly described below. The shaded components at the top of the diagram are external devices which are widely used in medical imaging systems.

Imaging System This is the device which produces the primary image information. Examples of these devices include CT scanners, ultrasound machines, x-ray fluorography systems, MRI systems, gamma cameras, PET scanners and computed radiography systems. The device is often physically separate from the other components as in the CT scanner, but may also be mounted in the same cabinet as the other components – as is the case for ultrasound machines. Image information produced by the imaging system is fed to the image acquisition circuitry of the digital image processor.

Connections from the digital image processor to the imaging system are generally also present, for controlling specific aspects of the operation of the imaging system, e.g. gantry movement of a SPECT camera. These additional connections are not shown in the figure for reasons of clarity.

Image Acquisition This component is used to convert the analogue information produced by the imaging system so that it is coded in the form of binary numbers. The type of device used for this purpose is called an Analogue-to-Digital Converter (ADC). The image acquisition component may also include circuitry for manipulating the digitised data so as to correct for any imaging aberrations. The type of device which can be used for this purpose is called an Input Look-Up Table. Examples of this type of data manipulation include pre-processing functions on ultrasound machines and logarithmic image transformation in digital fluorography systems.

Image Display This component is sometimes referred to as a display controller and its main use is to convert digital images into a form which is suitable for a visual display device. It includes a Digital-to-Analogue Converter (DAC) when a CRT monitor is used, for instance, and a digital visual interface (DVI) when a digital display such as an LCD monitor is used. The image display component can also include circuitry for manipulating the displayed images so as to enhance their appearance. The type of device which can be used for this purpose is called an Output Look-Up Table. Examples of this type of data manipulation include post-processing functions on ultrasound machines and windowing functions on Nuclear Medicine systems. Other forms of image processing provided by the image display component can include image magnification, image rotation/mirroring and the capability of displaying a number of images on one screen. This component can also allow for the annotation of displayed images with the patient name and details relevant to the patient's examination.

Image Memory This component typically consists of a volume of RAM which is sufficient for the storage of a number of images which are of current interest to the user.

Image Storage This component generally consists of magnetic disks of sufficient capacity to store large numbers of images which are not of current interest to the user and which may be transferred to image memory when required.

Image ALU This component consists of an ALU designed specifically for handling image data. It is generally used for relatively straight-forward calculations, such as image subtraction in DSA and the reduction of noise through averaging a sequence of images.

Array Processor This component consists of circuitry designed for more complex manipulation of image data and at higher speeds than the Image ALU. It typically consists of an additional CPU as well as specialised high speed data communication and storage circuitry. It may be viewed as a separate special-purpose computer whose design has traded a loss of operational flexibility for enhanced computational speed. This enhanced speed is provided by the capability of manipulating data in a parallel fashion as opposed to a sequential fashion (which is an approach widely used in general-purpose computing). This array processor is used, for example, for calculating Fast Fourier Transforms and for image reconstruction calculations in cross-sectional imaging modalities, such as CT, SPECT and MRI.

Image Data Bus This component consists of a very high speed communication link designed specifically for image data.

Digital Imaging
The digitisation of images generally consists of two concurrent processes – sampling and quantisation. These two processes are described briefly below and a consideration of the storage requirements for digital images follows.

Image Sampling This process is used to digitise the spatial information in an image. It is typically achieved by dividing an image into a square or rectangular array of sampling points. Each of the sampling points is referred to as a picture element – or pixel to use computer jargon.

The process may be summarised as the digitisation of an analogue image into an N x N array of pixel data. Examples of values for N are 128 for a nuclear medicine scan, 512 for CT and MRI scans, 1024 for a DSA image, and 2048 for a computed radiograph image and digital radiograph. Note that N has values which are integer powers of 2, because of the binary nature of modern computing techniques.

Naturally, the larger the number of pixels, the closer the spatial resolution of the digitised image approximates that of the original analogue image – see the images below.

Image Quantisation This process refers to the digitisation of the brightness information in an image. It is typically achieved by representing the brightness of a pixel by an integer whose value is proportional to the brightness. This integer is referred to as a 'pixel value' and the range of possible pixel values which a system can handle is referred to as the gray scale. Naturally, the greater the gray scale, the closer the brightness information in the digitised image approximates that of the original, analogue image – see the images below.

The process may be considered as the digitisation of image brightness into G shades of gray. The value of G is dependent on the binary nature of the information coding. Thus G is generally an integer power of 2, i.e. G=2m, where m is an integer which specifies the number of bits required for storage. Examples of values of G are 256 (m=8) in ultrasonography, 1024 (m=10) in DSA and 4096 (m=12) in nuclear medicine.

Digital Image Resolution The number of bits, b, required to represent an image in digital format is given by

b = N x N x m The following table shows the number of bits required to represent images which are digitised at different spatial resolutions for a range of gray scales. It is seen that very large values are required to achieve the resolution used in medical imaging (you might confirm as an exercise that the asterisked value in the Table represents 0.25 Mbytes). The resulting amounts of computer memory needed to store such images are therefore quite large and processing times can be relatively long when manipulating such large volumes of data. This feature of digital images gives rise to the need for dedicated hardware for image data which is separate from the components of a general-purpose computer as we have described above – although this distinction is vanishing with ongoing technological developments.

Digital Image Processing
Contrast enhancement as an example of a very common form of digital processing of images (also referred to as windowing) is described below. It is just one from the wide range of data manipulation processes which are available on modern systems. Contrast enhancement is a form of gray-level transformation where the real pixel values in an image are replaced by processed pixel values for display purposes. The process is generally performed using the Output Look-Up Table section of the image display component of the digital image processor. As a result, the original data in image memory is not affected by the process, so that from an operational viewpoint, the original image data can be readily retrieved in cases where an unsatisfactory output image is obtained. In addition, the process can be implemented at very high speed using modern electronic techniques so that, once again from an operational viewpoint, user-interactivity is possible.

An example of a Look-Up Table (LUT) which can be used for contrast enhancement is illustrated in the following figure. This information is usually presented using a graph of the real pixel values stored in image memory versus the pixel values used for display purposes. The process is generally controlled using two controls on the console of the digital image processor – the LEVEL control and the WINDOW control. It should be noted that variations in the names for these controls, and in their exact operation, exist between different systems but the general approach described here is sufficient for our purposes. It is seen the figure that the LEVEL controls the threshold value below which all pixels are displayed as black and the WINDOW controls a similar threshold value for a white output. The simultaneous use of the two controls allows the application of a gray-level window, of variable width, which can be placed anywhere along the gray scale. Subtle gray-level changes within images can therefore be enhanced so that they are displayed with greater clarity. A common application of this form of digital image processing in nuclear medicine is the removal of background counts from images.

Other forms of contrast enhancement used in Nuclear Medicine include using LUTs with logarithmic, exponential or other nonlinear input/output relationship – the logarithmic LUT being used for instance to accommodate a broad range of counts on one grey scale. Colour LUTs are also popular, where the digital contrast resolution of an image is represented by a range of different colours – a rainbow scheme for example as shown in the following figure – or by hues of one or a small number of colours.

Graphical representation of a Colour Look-Up Table (CLUT) which converts a grey scale into a spectrum of rainbow colours. The red, green and blue channels are represented by the plots with the respective colours.

Click HERE to view a QuickTime movie (~9 Mbyte) demonstrating the effects of various CLUTs on a fused SPECT/CT study.

Other examples of digital image processing are illustrated in figure below:

A detailed treatment of the image processing capabilities of a modern personal computer is provided at this external link.

Other common forms of digital image processing include applying geometric transformations to images so as to magnify or zoom in on specific details or to correct for geometric distortions introduced by the imaging system. Image zoom can be readily achieved in the display controller using a pixel replication process, where each pixel is displayed N2 times, where N is the zoom factor, as illustrated below:

A disadvantage of this approach however is that zoomed images can have a blocky appearance reflecting the larger size of each effective pixel. Although the application of a smoothing filter can reduce this pixelation effect, a more visually pleasing result can be generated using spatial interpolation techniques. Here, the pixel values of unknown pixels are estimated using the pixel values of known neighbouring pixels. Suppose the image above is zoomed again and suppose that this time the known pixels are distributed to the corners of the zoomed image, as shown in the following figure:

The task of the interpolation process is to calculate the pixel values of the unknown pixels based on the known pixel values of the corner pixels. The simplest approach is linear interpolation where a linear relationship between the pixel values of the known pixels is assumed. Let's suppose that we wish to estimate the pixel value of the pixel shaded red in the figure above. In the case of two-dimensional linear interpolation, also called bilinear interpolation, the first step is to calculate the pixel value of the pixel at position (x,0), shaded yellow on the top line of the matrix, as follows:

P(x,0) = x P(1,0) + (1-x) P(0,0)

where x : fractional distance along the horizontal axis.

Similarly, the pixel value of the pixel shaded yellow on the bottom line of the matrix, at position (x,1), is calculated using the following equation:

P(x,1) = x P(1,1) + (1-x) P(0,1)

Finally, the pixel value for the unknown red-shaded pixel in the figure can be obtained by linear interpolation between these two calculated (yellow-shaded) pixel values, as follows:

P(x,y) = y P(x,1) + (1-y) P(x,0)

where y : fractional distance along the vertical axis.

This process is applied to all unknown pixels in an image. Example images are shown below:

Functions other than linear can also be applied, e.g. two-dimensional polynomial and cubic spline interpolation, to effect a more visually pleasing result. Remember however that the interpolated data is not real and the approach simply generates estimates of pixel values in an effort to improve the blocky nature of the simple zoom technique considered earlier. We'll be considering further applications of image interpolation in our chapter on X-ray CT.

The Fourier Transform – A Pictorial Essay
The treatment of the Fourier Transform (FT) in many textbooks uses a level of mathematics which is quite alien to many students of the medical sciences. The treatment here will adopt a different approach, based on a pictorial essay, in an attempt to convey more effectively the concept on which the transform is based. It does in no way substitute for a rigorous mathematical treatment, and is solely aimed at supporting your understanding of image filtering.

This presentation will demonstrate that images can be thought about from both spatial and spatial frequency perspectives. The spatial perspective is the conventional way of presenting image data and relates to real world parameters such as distance and time. An image may also be considered as consisting of a large number of spatial frequencies interacting with each other. This aspect will be examined using a fairly simple image to begin with, and then by considering a more complicated one, namely a chest radiograph, i.e. an example of medical image which consists of a very broad range of spatial frequencies. The FT transforms the image data from the spatial representation to the spatial frequency representation and the inverse FT performs the reverse operation – see the figure on the right.

An image of a sinusoidal brightness pattern running at an angle of 45 degrees to the horizontal is shown below in panel (a). A plot of pixel values along the line AB demonstrates this sinusoidal pattern in one dimension as demonstrated in panel (b). It can also be represented in a different fashion by plotting the amplitude of the sine waves present in panel (b) against their spatial frequency. This is shown in panel (c). This latter plot confirms that there is just one spatial frequency dominating the image, as might be expected. This type of plot is called a 1D Fourier spectrum and utilises a one-dimensional FT of the image data. Note that panels (b) and (c) illustrate the frequency information in just one dimension.

When the frequency information is displayed in 2 dimensions, as in panel (d), it is called a 2D Fourier spectrum and this is achieved using a 2D FT of the image data. It demonstrates spatial frequencies for the vertical and horizontal image dimensions along its vertical and horizontal axes, with the origin at the centre (shown by the tiny white dot). Two other dots are seen in panel (d), with slight horizontal streaking beside them – one to the upper left and the other to the bottom right of the origin. These correspond to the frequency of the sine wave in panel (a). Since the FT generates both positive and negative values for the frequency, the resulting two frequencies are displayed on either side of the origin as indicated.

A more complicated 2-D Fourier spectrum is obtained when a chest radiograph is transformed to the spatial frequency domain as illustrated in the next figure. The transformed data show a broad range of spatial frequencies, with significant vertical and horizontal features, as might be expected from the horizontal ribs and vertical vertebral column displayed in the radiograph.

A potential use of the FT and its inverse is the removal of unwanted or corrupt data from a digital image and this process is illustrated in the final figure below. An extreme example of a corrupt image may be generated by adding together the two images just analysed, as in panel (a). The Fourier spectrum in panel (b) portrays the frequency characteristics of the summed image. The undesirable features attributable to the sinusoidal pattern may be removed by editing of the data in the frequency domain as in panel (c), before the inverse FT is performed to recover an image largely free of artifact, as in panel (d).

The key finding to be gleaned from these three examples is that the spatial and spatial frequency representations of the image data are entirely equivalent. The frequency representation has numerous advantages in terms of data manipulation. In general the FT and its inverse provide us with the tools to transform the data from the real world to one of spatial frequency and vice versa.

A more formal treatment of the Fourier transform is presented in our chapter on Fourier Methods.

Physikalische Grundlagen der Nuklearmedizin/ Computer in der Nuklearmedizin


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Horticulture/Pilea pumila

Pilea pumila, known as Clearweed, Canadian clearweed, Coolwort, or Richweed is an annual plant native to most of North America east of the Rockies. The plants are generally erect, 10 to 70 cm tall, often occurring in large colonies, and are quite common throughout their range both as a woodland plant and a weed of gardens.

Description
The foliage is opposite, simple with dentate margins, wrinkly (with depressed veins), ovate, and with long petioles. Both the leaves and stems are translucent and bright green, turning bright yellow in autumn. The flowers are small, borne in axillary cymes, unisexual with both genders occurring on the same plant, greenish yellow, and pollinated by wind. Flowers bloom from midsummer through early autumn. Fruits (achenes) are green with purple markings. Roots are fibrous, shallow, and adventitious off the stem in moist areas or when in contact with the soil.

Ecology
This plant is most often found in rich, moist soils in both sunny and shaded locations.

Uses
It is sometimes grown as a ground cover for its attractive foliage, but this should be done with caution as the plant easily gets out of control, and can develops long-lasting seed banks if allowed to go to seed. They do form a heavy canopy, and so will keep other weeds down quite effectively.

It can also be grown as forage for deer and goats.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Horticulture/Pilea pumila


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Template:FOSS Localization

 FOSS Localization Foreword — Acknowledgements — Introduction — Localization Efforts in the Asia-Pacific — Recommendations — Annex A: Key Concepts — Annex B: Technical Aspects — Further Reading — Resources and Tools — Glossary — About the Authors — About APDIP — About IOSN

title: Template:FOSS Localization


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User talk:Xrayman

Hello my name is Richard.

I am an Electronics Engineer and Writer/Editor. I have a Diploma in Human Biology and six years experience in the maintenance of MRI and Nuclear Medicine equipment.

I presently teach Electronics to Technicians and Engineers responsible for the Airspace over Australia (specifically navigational aids and Radio/Radar)

For more information, go to:

http://www.freewebs.com/read-write

Glad to assist where I can.

Cell Biology Textbook
Hey Richard, I saw you made some contributions to the Cell Biology textbook and that biology is your expertise. I'm working with the Saylor Foundation to produce a similar textbook to host on our website for one of our courses. If you are interested, we would love for you to check out Saylor.org's Cell Biology and make some contributions! --Azin (discuss • contribs) 16:40, 4 June 2012 (UTC)

title: User talk:Xrayman


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Template:FOSS Open Standards

 FOSS Open Standards

Foreword — Preface — List of Acronyms — Introduction — Importance and Benefits of Open Standards — Standard-Setting and Open Standards — Some Important Open Standards — Comparison of File Formats — Standards and Internationalization/Localization of Software — Patents in Standards — The Linux Standard Base — Government/National Open Standards Policies and Initiatives — Conclusion — Annexure: Comments on RAND, as seen from both sides — Glossary — About the Author — Acknowledgements — About APDIP — About IOSN

title: Template:FOSS Open Standards


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FOSS A General Introduction/About APDIP

The Asia-Paciﬁc Development Information Programme (APDIP) is an initiative of the United Nations Development Programme (UNDP) that aims to promote the development and application of new Information and Communication Technologies (ICT) for poverty alleviation and sustainable human development in the Asia-Paciﬁc region. It does so through three core programme areas, namely, Policy Development and Dialogue; Access; and Content Development and Knowledge Management.

In collaboration with national governments, APDIP seeks to assist national and regional institutions in the Asia-Pacific through activities that involve awareness-raising and advocacy, building capacities, promoting ICT policies and dialogue, promoting equitable access to tools and technologies, knowledge sharing, and networking. Strategic public-private sector partnerships and opportunities for technical cooperation among developing countries (TCDC) are APDIP's key building blocks in implementing each programme activity

title: FOSS A General Introduction/About APDIP


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SPM/Non-sphericity

=Non-sphericity specification in SPM5=

GUI
In batch mode for factorial design specification, one can specify whether error variances are unequal across the levels of a factor and whether error variances are correlated between different levels of the same factor.

Script, SPM.mat
After the design has been specified, SPM.xVi.Vi will hold a cell array of non-sphericity component matrices. Each matrix should have as many rows and columns as you have images in your design. A 1 in a certain row i and column j means that images i and j are assumed to have dependent error covariance. Note the special case if i==j, this encodes for the error variance of image i.

If you are not satisfied with SPMs suggestions for error covariances, you can insert your own list of Vi components after design specification, before you estimate the model.

Verification of covariance specifications
Covariance components can be verified using SPMs Review Design facility - in the Menu there is an item called Explore Covariance structure.

title: SPM/Non-sphericity


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FOSS A General Introduction/About IOSN

The International Open Source Network (IOSN) is an initiative of UNDP’s Asia-Paciﬁc Development Information Programme (APDIP). Its overall objective is to serve as a Center of Excellence and a Clearinghouse for Information on Free and Open Source Software (FOSS) in the Asia-Paciﬁc region. In order to accelerate the world-wide adoption of FOSS, IOSN seeks to raise awareness, facilitate networking of people, strengthen capacities, and conduct R&D.

The beneﬁciaries of IOSN are governments, IT professionals, software developers, the FOSS R&D community, academics and the NGO community. IOSN serves as a resource center to help policy-makers and decision-makers in the public sector, educational institutions, businesses and others develop policies and plans for the use of FOSS in their respective organizations. Much of IOSN’s activities are undertaken online and the IOSN portal has been developed for this purpose and serves as a comprehensive online resource center on FOSS. The IOSN portal also provides a means for the FOSS community in the region to contribute to its efforts and to interact with each other.

http://www.iosn.net

title: FOSS A General Introduction/About IOSN


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Horticulture/Persicaria

Smartweeds are a group of plants in the genus Persicaria, which are usually encountered either as wildflowers or as weeds of lawns and gardens. The majority are annuals.

Description
Plants in this genus have swollen nodes and alternate, simple, spearhead-shaped leaves. The small flowers are held above the foliage on spikes, and are either pink or white. Flowers are borne from late spring through mid autumn, the seeds are likewise white or pink. Plants can be prostrate or bushy, depending on growing conditions and species.

Ecology
Smartweeds can be aggressive weeds of lawns and gardens, walkways, and patios, growing in both rich and poor soils.

Uses
Like buckwheat (which is closely related), the smartweeds can be used as a cover crop or green manure source, though self-seeding can become a nuisance if the plants are not mowed down before the seeds mature.

Some species and varieties are also grown as ornamental plants.

title: Horticulture/Persicaria


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Adventist Youth Honors Answer Book/Stars/Planets

The planets in our solar system, starting from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was also considered a planet from 1930 until 2006 when the International Astronomer's Union (IAU) was prompted by the discovery Eris, a body larger than Pluto, to come up with a formal definition of the word "planet." For years leading up to this announcement there had been rumblings in the scientific community that classifying Pluto as a planet had been a mistake, much as the classification of Ceres, the largest asteroid had been a mistake in the 1800's. After the discovery of Ceres, more and more asteroids were discovered, and it became increasingly clear that it was not a planet. The same thing began to happen in the late 1900's when astronomers began to discover several Pluto-like objects in the Kuiper belt. The debate came to a head with the discovery of Eris, which has a diameter that exceeds Pluto's by 70 miles (110 km). The IAU would have to either recognize Eris as the tenth planet or "demote" Pluto. The demotion of Pluto, though not popular with the general public, makes the most scientific sense and demonstrates that science is capable of correcting its errors.

The new definition of a planet requires that an object a) orbit a star (such as the Sun), b) not orbit another planet (such as a satellite), and c) dominate the vicinity of its orbit. Pluto did not make the cut because its orbit is dominated by Neptune, and there are many objects orbiting in its vicinity that Pluto has no effect upon.

There are a number of mnemonic phrases that are easily memorized for remembering the names of the planets, including "My Very Energetic Mother Just Served Us Noodles.

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Introduction to Psychology/Psychophysics

Psychophysics is the branch of Psychology dealing with the study of relationship between physical stimuli and individual perception. Perception is a general concept which refers to interpretation of a stimuli received by the senses. The are number of factors that affect the perception. Even the same stimuli can give different perceptions at different situations. Some of the factors that affect the perception are the individual's expectations, similarity, proximity, continuity and closure.

The propounder of the concept or discipline of psychophysics was Gustav Theodor Fechner. The concept was first mentioned in his work Elemente der Psychophysik in 1860.


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Adventist Youth Honors Answer Book/Stars/Planet

The short answer: A planet is a large body that orbits a star, and dominates the vicinity of its orbit.

The long answer: Believe it or not, until 2006 there was no formal scientific definition of the word planet. Most of us have been taught that there are nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. The asteroids were at one time also considered to be planets, but scientists soon realized that they were different - there were many of them, and they were all in the same general region of the solar system, sharing orbits between Mars and Jupiter. Pluto was not discovered until 1930, and it was soon heralded as the ninth planet. But technology improved, and scientists began to discover that there were many other bodies similar to Pluto in that same region of the solar system (called the Kuiper Belt). It eventually became obvious that Pluto should never have been called a planet, but by the time that happened, Pluto was entrenched. Popular culture would not allow scientists to "demote" Pluto to non-planetary status. So scientists left it alone. After all, none of the other Kuiper Belt Objects (or KBO's) were as large as Pluto, so the problem could be ignored.

In 2005 an object named Eris was discovered in the Kuiper Belt beyond the orbit of Pluto. And it is larger than Pluto. The discovery of Eris forced the scientific community to come up with a formal definition of the word "planet," and that definition corrected the misclassification of Pluto as a planet.

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Horticulture/Seed Banking

Seed Banking refers to populations of seeds in the soil over long periods, primarily applied to weeds. Many weeds create seed banks, which allow them to germinate even if the previous year's plants did not have an opportunity to set seeds.

What can be done

 * 1) Prevent weeds from going to seed. Though this will not affect the seeds already in the soil, it will help prevent the problem from getting any worse, and eventually will run the seed bank down (as most seeds are not immortal, even though they might seem that way).
 * 2) Mulching in late winter or early spring will keep seeds from being exposed to light, which is the most common metabolic signal for germination.
 * 3) "Stale beds" can be created by repeated tilling or other methods of cultivation
 * 4) Pre-emergent herbicides can prevent the germination of many weed seeds.

title: Horticulture/Seed Banking


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Horticulture/The Benefits of Compost

<Horticulture/Soils and Composts Compost is a true “magic bullet” in the garden, fixing many problems in the soil that are reflected by unhealthy plants. The benefits of compost are many, and can sometimes seem inconsistent, as in some cases it achieves two goals that appear to be opposites. The start of any good garden is good soil, and adding compost is the easiest and most long-lasting way to improve soil conditions.

Drainage and Water Retention
Pick up any good garden book, and you’ll notice that most garden plants like a “moist, well-drained soil”. This means that the soil should hold plenty of water for plants to use as they need it, while at the same time draining quickly after heavy rainfalls or overly enthusiastic irrigation. This seems like a tall order for a soil, but is easily achieved by adding compost.

Compost improves water retention because of its sponge-like nature. Mature compost (also called humus) can hold up to 200 times its weight in water! This means that rainwater or irrigation water stays in the soil, rather than leaching out or running off. Soils rich in humus therefore need less frequent irrigation, saving time, worry and money for the garden-owner.

Compost also improves drainage, which is important because roots need oxygen to survive. This improved drainage happens because compost binds up the soil into little crumbly bits, leaving good-sized air spaces in between. It might seem a bit strange that it allows more air in at the same time as holding more water, but the water is held inside the crumbs, while the air moves between them.

Fertilization and Nutrient Retention
Most garden plants prefer a balanced, nutritious soil (though there are a few that don’t like a lot of nutrients, so be careful). Compost helps create and maintain a nutritious soil solution for plants to use.

When compost is added to a soil, it brings nutrients with it. Compost is, after all, what’s left after bacteria, fungi, and other creatures get done breaking down dead tissues, and so contains the basic components used by plants to produce new tissues. Compost is a slow-acting fertilizer, and lasts a long time in the soil, especially in comparison to salt-based synthetic fertilizers.

Compost also improves the soil’s ability to hold nutrients, as it has many “pockets” where nutrients can be held ready for the roots to use. This soil property (called the “Cation Exchange Capacity”, or CEC) means that most nutrients added to the soil stay bound up, rather than leaching out. Compost also helps keep Nitrate in the soil (which is an anion), which is important because Nitrogen is the most easily leached soil nutrient.

Buffering
Aside from good drainage, water retention, and fertility, plants also benefit from a soil that is stable. The “moist, well-drained” property of a good soil is one sort of stability, as is the slow, constant supply of nutrients available in humus-rich soils. Another kind of stability is also quite important, namely the stability of the soil’s pH value. The soil’s pH (the power or activity of Hydrogen ions) is a measurement of acidity or alkalinity. Different nutrients and toxins become available to the plants depending on the pH value of the soil, and if the pH varies every time there is a rain event or irrigation, the plants find the available nutrients out of balance. In soils with a low CEC, the pH can be changed quite dramatically by acidic rainfalls or alkaline irrigation water.

Compost stabilizes the pH of the soil because it significantly raises the soil’s CEC. The acids and alkalis that arrive with those life-giving waters are taken up in those “pockets”, rather than floating around in the water held by the soil. This really helps plants live a healthier life.

The one thing to keep in mind is that if there is a high humus content in the soil, it will be more difficult to change the pH when you want it changed. One should never try to change the soil’s pH without a soil test in any case, as the amount you’d use to slightly alter a humus-rich soil would drastically alter a humus-poor soil.

Bio-activity
Compost is living, breathing stuff. Composts contain residues (which have not yet been completely broken down), humus, and a “microflora” made up of many species of bacteria and fungi. These bacteria and fungi are important for maintaining the stability of the soil, and help break down and organic fertilizers that might be added to the soil when necessary.

Keeping the soil alive helps nutrients spread out for an even distribution, and helps fight plant diseases by filling the “pockets” where disease organisms might find a home. Some of these “good guy” organisms will even eat the bad ones, turning them into more nutrients for your plants. This property, called “antagonism”, is very important in keeping plants healthy and strong.

Aesthetic Benefits
Aside from all the hard-science benefits, compost also makes the soil more pleasant to be around and work with. The soluble parts of compost turn the soil a rich, dark color, which is just as nutritious as it looks. Compost also provides that wonderful “earthy” smell after a rain, which some folks find even more invigorating than the aroma of a good cup of coffee. For the gardener, compost rich soils have a nice, crumbly feel between the fingers, and are easy to dig in.

/Composting

title: Horticulture/The Benefits of Compost


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Horticulture/Cirsium arvense

Cirsium arvense, known as Creeping Thistle or Canada Thistle, is a species of the genus Cirsium, native throughout Europe, Asia and northern Africa.

Description
It is a tall herbaceous perennial plant, forming an extensive underground root system that sends up numerous erect stems each spring, reaching 1–2 m tall; the stems often lie partly flat by summer but can stay erect if supported by other vegetation. The leaves are very spiny, lobed, up to 15–20 cm long and 2–3 cm broad (smaller on the upper part of the flower stem). The inflorescence is 1–2 cm diameter, pink-purple, with all the florets of similar form (no division into disc and ray florets). The seeds are 4–5 mm long, with a downy pappus which assists in wind dispersal.

It is a nuisance weed in its native area, and a very serious invasive species in many other areas of the world.

Uses
Cirsium species, are, for the most part, not toxic; however, the leaves are considered bitter and therefore rendered inedible; the taproot is considered the most nutritious. In Scotland (especially Fife) they are considered a delicacy, albeit a somewhat unusual one.

Control
This plant is extremely difficult to control, as it can regrow from fairly small root fragments and is resistant to many herbicides.

 * Pre-emergents can help prevent the plant from becoming established, but it is generally more often encountered as a perennial problem.
 * Contact herbicides are only partially effective. Glyphosate in particular needs to be repeatedly applied.
 * Mowing is effective over time, if done regularly.
 * Goldenrods are allelopathic to this plant. Smothercropping of buckwheat and winter rye will also weaken the plant considerably.
 * Pulling must be done repeatedly over a long period, but will eventually kill the plant. Gloves should be worn.
 * Smothering techniques such as paper mulch barriers are quite effective.
 * Canada thistle should never be added to a cold-composting system. All parts of the plant should be burned, thrown away, or put into high-temperature composting systems.

title: Horticulture/Cirsium arvense


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Talk:Horticulture/Cirsium arvense

Page history from Cirsium arvense
(cur) (last) 18:10, 5 September 2006 Kaarel (Talk | contribs) m (cur) (last)  14:01, 4 August 2006 81.231.3.83 (Talk) (+sv) (cur) (last) 20:11, 7 July 2006 Slaweks (Talk | contribs) m (link) (cur) (last) 09:53, 22 June 2006 SB Johnny (Talk | contribs) (added prevalent common name to top) (cur) (last) 05:15, 20 June 2006 Sunholm (Talk | contribs) (Edibility) (cur) (last) 09:56, 18 June 2006 Sunholm (Talk | contribs) (Formatting!) (cur) (last) 09:56, 18 June 2006 Sunholm (Talk | contribs) (Edibility) (cur) (last) 04:44, 2 May 2006 88.240.62.10 (Talk) (cur) (last) 07:33, 21 March 2006 YurikBot (Talk | contribs) m (robot Adding: fi:Pelto-ohdake) (cur) (last) 19:53, 31 January 2006 Gdrbot (Talk | contribs) m (nomialbot — converted multi-template taxobox to ) (cur) (last) 08:08, 20 December 2005 Hede2000 (Talk | contribs) m (+da:) (cur) (last) 15:25, 30 November 2005 MPF (Talk | contribs) m (italics) (cur) (last) 15:10, 30 November 2005 MPF (Talk | contribs) m (rm duplication) (cur) (last) 22:42, 29 November 2005 Zotel (Talk | contribs) m (de-italisize) (cur) (last) 10:03, 30 September 2005 Petaholmes (Talk | contribs) (other common name) (cur) (last) 17:53, 21 September 2005 RobotE (Talk | contribs) m (robot Adding: de, fr, nl) (cur) (last) 13:25, 12 August 2005 Circeus (Talk | contribs) m (not quite a stub) (cur) (last) 18:13, 2 July 2005 Gdrbot (Talk | contribs) m (Robot-assisted disambiguation: Scop.) (cur) (last) 18:07, 2 July 2005 Gdrbot (Talk | contribs) m (Robot-assisted disambiguation: L.) (cur) (last) 17:15, 29 June 2005 MPF (Talk | contribs) m (link corrected) (cur) (last) 17:15, 29 June 2005 MPF (Talk | contribs) (new page start)

title: Talk:Horticulture/Cirsium arvense


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Control Systems/System Representations

System Representations
This is a table of times when it is appropriate to use each different type of system representation:

General Description
These are the general external system descriptions. y is the system output, h is the system response characteristic, and x is the system input. In the time-variant cases, the general description is also known as the convolution description.

State-Space Equations
These are the state-space representations for a system. y is the system output, x is the internal system state, and u is the system input. The matrices A, B, C, and D are coefficient matrices.

These are the digital versions of the equations listed above. All the variables have the same meanings, except that the systems are digital.

Transfer Functions
These are the transfer function descriptions, obtained by using the Laplace Transform or the Z-Transform on the general system descriptions listed above. Y is the system output, H is the system transfer function, and X is the system input.

Transfer Matrix
This is the transfer matrix system description. This representation can be obtained by taking the Laplace or Z transforms of the state-space equations. In the SISO case, these equations reduce to the transfer function representations listed above. In the MIMO case, Y is the vector of system outputs, X is the vector of system inputs, and H is the transfer matrix that relates each input X to each output Y.

title: Control Systems/System Representations


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AQA Information and Communication Technology/ICT6

ICT 6 is a module in AQA A2 syllabus. It is coursework based and has to be a system in MS Access should be a real end user, rather than a situation being 'fabricated'. Some students still choose to create an imaginary problem but often score very low marks in the 'Analysis' section.


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Social and Cultural Foundations of American Education

'''Social and Cultural Foundations

of American Education'''

 * /Development Process/
 * /Foreword/

 * 1) /Philosophy and Ethics/
 * 2) /Dynamic Learning Environment/
 * 3) The History of American Education
 * 4) Educational Change and the Future of Education
 * 5) Some of the Barriers to Effective Education
 * 6) /Classroom Issues/
 * 7) The Forgotten Half: Those Who Do Not Succeed in American Schools
 * 8) /Staffing Practices/
 * 9) Administering the Schools
 * 10) /Curriculum Development/
 * 11) Technology in Education
 * 12) School/Community/Parental Relationships
 * 13) /Multiculturalism/
 * 14) Knowing What We Know, Knowing What They Know
 * 15) Assessment Practices in Education
 * 16) Acknowledging Differences and Complexity
 * 17) /Accountability/
 * 18) /Choice/
 * 19) Student Assessment and Feedback
 * 20) /Special Needs/
 * 21) Hot Topics in Education
 * Expanded Table of Contents


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Adventist Youth Honors Answer Book/Stars/Daily motion

The stars appear to move in two different ways. The first way is caused by the Earth's rotation on its axis which causes the stars (and the Sun and the Moon) to rise in the east and set in the west. The second way stars appear to move is caused by the Earth's orbit around the sun, which causes any given star to rise earlier and earlier each night.

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Wikibooks:Request for enabling special:import

What Special:Import does
This tool is used for transwiki, available to administrators. I have used it on wikiversity to import pages from wikibooks and meta to wikiversity. In contrast to the copy-and-paste transwikis that are the current norm, imports bring over the entire page history with all changes.

Advantages

 * 1) Import ensures that page edit histories are brought over, in better compliance to the GFDL than the current system of copying the page history, because one can search the history to distinguish between major and minor edits, etc.
 * 2) Import would put the transwiki-from-elsewhere process firmly in the hands of people on the wikibooks side, rather than the random dropping of materials that happens now. Hopefully the wikipedians/wikiversitans/etc. can be convinced to make this a policy on their sides as well.
 * 3) Using import rather than manual transwiki might help remove the "stigma" of materials being "exiled" into wikibooks (a feeling I myself suffered from for quite some time as a wikipedian).

Disadvantages

 * 1) Naturally, this means more work for administrators.
 * 2) Using edit counts for voting elegibility will go out the window, since any edits made on a wikipedia page before the import will be attributed to that username on wikibooks.

Votes (wikibookians)
(Support or Oppose with comments. If undecided, use the talk page.)

 * 1) Support -- SB_Johnny | talk (I'm the one making the proposal, so of course I support it :).)
 * 2) Support If material is moving to here from there, then it makes sense to facilitate that movement. --Whiteknight (talk) (projects) 15:55, 14 September 2006 (UTC)
 * 3) Support good idea, makes users requesting imports able to make use of new material quicker with edit history intact. --darklama 23:54, 8 October 2006 (UTC)
 * 4) Support The disadvantages don't seet too worrysome. Cleanup after sloppy copy-pastes will mostly fall on admins anyway as they do much of that type of work anyway. Measuring voting elegebility will not be completely out the window, but sometimes it may be difficult to see if a user's edits are wikibookian edits. --Swift 14:58, 9 October 2006 (UTC)
 * 5) Support. This is an invaluable and foolproof tool. If this goes through I think cut-n-paste transwikiing should be banned altogether. GarrettTalk 23:28, 12 October 2006 (UTC)
 * 6) Support. Does anyone know how many pages might be expected to be imported to Wikibooks in a year? --JWSurf 00:38, 13 October 2006 (UTC)
 * 7) support - Makes preserving the history, a requirement of the GFDL, easier. Easier is better. Gentgeen (I'm also a wikipedian) 03:24, 13 October 2006 (UTC)
 * 8)  Support Better tools are good for everybody. Kellen T 09:50, 13 October 2006 (UTC)
 * 9) Very Strong Support -- More like why isn't this turned on by default?  As far as the number of pages imported to Wikibooks in a year, it is on the order of about 500-1000 pages (at least for last year).  Or about 3-5 pages per day on average unless admins are getting lax.  Much of that is cruft that an admin might not import directly, but much of it is content marked for deletion on Wikipedia and other Wikimedia projects.  This has been an invaluable tool on Wikiversity, and I'm very, very, very, (to the point of ad nausium) glad that I have the option to use this tool to move content from Wikibooks to Wikiversity.  Performing similar content transwiki without this tool (for example, the Wikimania content) was a total pain in the rear.  It has its shortcomings and bugs, but it is very much worth it.  --Rob Horning 20:50, 20 October 2006 (UTC)

Votes (wikipedians, see talk)

 * Facilitates moves of materials to where they belong. This is good for the Wikipedia project, and so I support it. --Improv 16:16, 5 October 2006 (UTC)

=Additional request=

Special:Import is now enabled. A few more votes for the following (wikimedia only requires a few) would further facilitate the process:

Part 2: make "Transwiki:" a full namespace:

By making transwiki a namespace, we will be able to put the imports there directly, rather than importing into the main namespace. This has 2 main advantages:
 * 1. No clutter in the main namespace.
 * 2. This would allow for stable redirects for use on the wikipedia side (makes the templating easier). The Transwiki:Pagename could then just have a redirect to the page's actual location. (Note that wikipedians frequently complain that the pages they thought were moved here don't seem to be here... in most cases they actually are here, but wikipedians are generally not accustomed to our way of naming things (as books and chapters), and the fact that a search on wikibooks isn't going to move them straight to an article).

Votes

 * Support -- SB_Johnny | talk 19:44, 16 October 2006 (UTC)
 * Support. and after this you are going to tell us that you absolutely must have something else that requires a vote, I suppose? I'm just kidding with you, this makes good sense. --Whiteknight (talk) (projects) 19:50, 16 October 2006 (UTC)
 * LOL. No, not for a while. If we like the way it's working for the forking purposes, we might want to enable import from wikisource for annotated books, but let's take it one step at a time :). I had meant to ask for this at the same time (actually, I meant to ask guillom to ask for it at the same time), but managed to drop off irc before he mentioned that buzilla would want a show of support for this too. -- SB_Johnny | talk 19:55, 16 October 2006 (UTC)

 * Support --darklama 20:15, 16 October 2006 (UTC)
 * Support --Derbeth talk 21:07, 16 October 2006 (UTC)
 * Support --Swift 21:18, 16 October 2006 (UTC)
 * Support --Panic 21:21, 16 October 2006 (UTC)
 * Support --Kempm 21:29, 16 October 2006 (UTC)
 * Support I hope this becomes a standard feature of MediaWiki. --JWSurf 02:31, 17 October 2006 (UTC)
 * Actually, the import feature itself is not a standard feature of MediaWiki because the single login is not enabled yet, thus making accounts conflicts possible. guillom 11:04, 17 October 2006 (UTC)
 * Support, obviously. GarrettTalk 06:11, 17 October 2006 (UTC)
 * Support Dude. Kellen T 08:05, 17 October 2006 (UTC)
 * Support I think this is an outstanding idea. Of course, the "Transwiki" namespace does need some current cleanup for a couple of fools that have nothing better to do with their time.  I would also agree that this ought to be a standard feature of MediaWiki.  --Rob Horning 20:53, 20 October 2006 (UTC)

 * Requested in 7613. guillom 11:02, 17 October 2006 (UTC)


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Adventist Youth Honors Answer Book/Stars/Satellite

A satellite is an object that orbits a planet. There are two basic types of satellites: natural, and artificial. Our Moon is a natural satellite, and all the planets beyond Earth's orbit have them as well (we keep discovering more and more of them, so it's hard to put a number on it). The other type of satellite is an artificial satellite, and these are most often used for communications (think satellite TV dishes).

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Adventist Youth Honors Answer Book/Stars/Comet

A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail — both due primarily to the effects of solar radiation upon the comet's nucleus, which itself is a minor planet composed of rock, dust, and ices.

Comets have highly elliptical orbits; they come very close to the sun (within the orbit of Mercury), and then they go way out to the edges of the solar system, far beyond even the orbit of Pluto. Because they travel over such a huge distance, it takes them many years to complete an orbit.

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Adventist Youth Honors Answer Book/Stars/Meteor

A meteor is the visible path of a meteoroid that enters the Earth's (or another body's) atmosphere, commonly called a shooting star or falling star.

Meteors look a lot like comets in photographs but can easily be distinguished from them because a comet's motion can only be discerned by observing it for several hours, while a meteor's motion is immediately obvious (they are very fast and brief). An individual meteor can only be seen for at most a few seconds while a comet can be seen for days or weeks.

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Adventist Youth Honors Answer Book/Stars/Nebula

A nebula is an interstellar cloud of dust, gas and plasma. Interstellar is a word meaning "between or among the stars." Nebulae are among the most beautiful objects in the night sky. Perhaps one of the most famous and easily recognized space objects, the Eagle Nebula (also known as Messier Object 16, M16 or NGC 6611) is a young open cluster of stars in the constellation Serpens.

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Adventist Youth Honors Answer Book/Stars/Constellation

A constellation is any one of the 88 areas into which the sky - or the celestial sphere - is divided. The term is also often used less formally to denote a group of stars visibly related to each other in a particular configuration or pattern.

Some well-known constellations contain striking and familiar patterns of bright stars. Examples are Ursa Major (containing the Big Dipper), and Orion (containing a figure of a hunter). Other constellations do not encompass any discernible star patterns, and contain only faint stars.

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Adventist Youth Honors Answer Book/Stars/Fixed star

A fixed star (from the Latin stellae fixae) is any celestial object that does not seem to move in relation to the other stars of the night sky. Hence, a fixed star is any star except for the Sun. A nebula or other star-like object may also be called a fixed star.

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Adventist Youth Honors Answer Book/Stars/Sunspot

A sunspot is a region on the Sun's surface that is marked by a lower temperature than its surroundings and intense magnetic activity, forming areas of low surface temperature. Although they are blindingly bright, at temperatures of roughly 4000-4500° K, the contrast with the surrounding material at some 5700° K leaves them clearly visible as dark spots. If they were isolated from the surrounding photosphere they would be brighter than an electric arc.

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Adventist Youth Honors Answer Book/Stars/Terms

 * a. Celestial sphere: The celestial sphere is an imaginary rotating sphere of "gigantic radius", with the Earth at its center. All objects in the sky can be thought of as lying upon the sphere.
 * b. Celestial pole: The two celestial poles are the imaginary points where the Earth's spin axis intersects the celestial sphere. The north celestial pole currently has nearly the same coordinates as the bright star Polaris (which is Latin for "Pole Star").
 * c. Celestial equator: The celestial equator is a great circle on the imaginary celestial sphere, which is actually the plane of the terrestrial equator extended out into the universe (i.e., it could be constructed by extrapolating the Earth's equator until it touches the celestial sphere).
 * d. Horizon: The horizon is the line that separates earth from sky.
 * e. Right ascension: Right Ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. It is equivalent to terrestrial longitude.
 * f. Declination: Declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Dec is comparable to latitude, projected unto the celestial sphere, and is measured in degrees north and south of the celestial equator. Therefore, points north of the celestial equator have positive declination, while those to the south have negative declination.
 * g. Transit: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at some particular vantage point.
 * h. Conjunction: Conjunction means that, as seen from some place (usually the Earth), two celestial bodies appear near one another in the sky.
 * i. Ecliptic: The Ecliptic is the apparent path of the Sun traced out along the sky in the course of the year. More accurately, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun.

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Adventist Youth Honors Answer Book/Stars/Telescope

A refractor telescope is a type of optical telescope that refracts or bends light at each end using lenses. A reflector telescope is a telescope which uses a combination of curved and flat mirrors to reflect light and form an image, rather than lenses to refract or bend light to form an image.

An equatorial mount is a mount used for moving a telescope or camera along two perpendicular axes of motion (right ascension and declination). The telescope mount's axis of right ascension should be pointed directly towards whichever celestial pole is above the horizon to work correctly.

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Wikibooks talk:Request for enabling special:import

Other stuff

 * I'd like to see the tool configured to automatically add pages to the Transwiki: namespace. Shouldn't be a problem for the devs.
 * Please note that I'm hoping to get Import enabled on Wikibooks, not Export enabled on other projects (that would just make the nightmare worse!) -- SB_Johnny | talk 15:51, 14 September 2006 (UTC)

On the disadvantages

 * As far as making more work, I'm willing to do quite a bit of it. I think there should be someone from the cookbook to look over recipes posted there however, since a substantial portion of the articles in w:Category:Copy to Wikibooks are recipes. (And does anyone actually work on the Bartending book, or is that pretty much a transwiki dump?)
 * Another potential problem related to adding to the edit counts through Import is that it will also raise the edit counts of vandals. On the other hand, this would also identify IP vandals to us here, since we'd have a better view of their histories. In many cases, simply removing the vandal edits from the histories might be a good idea. -- SB_Johnny | talk 15:51, 14 September 2006 (UTC)

The "wikipedian votes" section
I'm advertising this on en.wikipedia's villiage pump, since it effects them as much as it effects us (i.e., this will make the cleaning up of w:Category:Copy to Wikibooks and w:Category:Articles containing how-to sections a lot easier for us, and therefore easier for them. -- SB_Johnny | talk 15:35, 3 October 2006 (UTC)

How would it work?
How would Import work? How would an import feature determan what to import? Would pages link to get imported? Would it perhap show a list of pages linked to that may need to be imported as well giving the chance to remove pages not to be imported? Would links referring to pages not imported be changed automatically so links aren't left broken? Would the edit history indicate where the page(s) were imported from? What about templates used or catagories that the page(s) belonged to?

Even though I'm not an admin, I would be willing to support it too, if it means less work for admins. Sounds to me like there would still be pleanty of work to do if all it does is import edit history as well. I think it would benifit from also trying to clean up whats imported, making even less work for admins or other users who wish to help once imported. --darklama 16:37, 7 October 2006 (UTC)

 * It's fairly similar to the way "move page" works within wikibooks, but it leaves the original where it was. What gets transwikied depends on the reason for the move... some stuff gets requested for move on the other project (see w:Category:Copy to Wikibooks for examples), others might be imposted because someone wants them here (e.g., if you wanted to write a book on energy efficiency, you might want to import a number of wikipedia articles on the subject and arrange them here as book chapters)... we'd just need to set up a "requests for import" page here for that.
 * Unfortunately I don't know how to make screen shots, or I'd just post what the dialog box looks like, but it just asks you what project to import from and what page you want to import, then click the import button and it's done. The pagehistory comes with the page, but the talk page (and it's history) require a second round, then it has to be moved to it's final location here (using normal pagemove). When we move to SUL, this will mean anyone who had contributed on the other project would also be marked as having contributed to the module here.
 * It doesn't moved linked pages... that would be a nightmare if you think about it (a lot of wikipedia pages in particular have hundreds of linked pages). -- SB_Johnny | talk 23:24, 8 October 2006 (UTC)

Please vote on bugzilla...
See http://bugzilla.wikimedia.org/show_bug.cgi?id=7579 for details. -- SB_Johnny | talk 17:04, 15 October 2006 (UTC)

Transwiki namespace
If this section is approved, it will require a bot to go through all the Talk:Transwiki:Foo pages and move them to Transwiki talk:Foo. Gentgeen 20:56, 16 October 2006 (UTC)

 * We've got bots a'plenty... no worries :). -- SB_Johnny | talk 10:33, 17 October 2006 (UTC)


text:
Horticulture/Pulling Weeds

Often the easiest and most effective way to control weeds is to simply pull them out by the root and dispose of them.

Getting to know the weeds
The first step in removing weeds from a garden is knowing which plants are weeds, and which are not. Inexperienced gardeners should always have an identification guide handy to help with this, or use on-line resources such as the Bloom Clock on Wikiversity. Once identified, further reading will let the gardener know what kind of root system the weeds have, how they set seed, and whether they are safe to compost.

Start pulling
Once the weeds are identified, the gardener should start pulling them out. If soil consitions are not conducive to getting the full root out (e.g., too dry or frozen), it's generally better to either change the conditions first (e.g., by watering) or just coming back another time, since most weeds will regrow from the root if only the tops are removed.

Many weeds will simply break off at the ground if pulled using a quick, jerking motion, so pull slowly but firmly to ease the whole plant out of the ground. If a root will not come out, either use a tool such as a hand cultivator or mattock to grub it out, or for large weeds (particularly woody ones), just cut it below ground level using loppers.

Dispose of quickly and properly
Never leave weeds in piles, either in the garden bed or on an adjacent lawn or other surface, since in many cases the seeds will continue to mature and disperse even after the weeds have been pulled. Most weeds can be composted, though if seeds are present heat composting may be required. Some weeds should simply be burned or sent to the landfill if they are particularly invasive.

/Weeds/Controls

title: Horticulture/Pulling Weeds


text:
FOSS Open Standards/Foreword

One promise of the United Nations (UN), when it was founded in 1948, was to be the voice of those less advantaged and disenfranchised. And within that promise was the thought that the UN could and would lobby on behalf of those who could not act on their own behalf. The United Nations' history is rich with successful intervention, especially for the aged and children. I am reminded of this continued work as I leave Sydney, Australia, late in March, 2006, having seen the Bears of the World on behalf of UNICEF. This decorative display brings a smile to all who move about this collage of bears representing each world nation with unique and vibrant colour schemes. Each individual or group seeks its homeland of today or the heritage of their ancestors. And it is all great fun on behalf of humanity's most vulnerable constituents, children. UNICEF remains UN's most cherished and successful endeavour.

Approaching its 60th birthday, UN has undertaken another very meaningful and important initiative that seeks to continue its original mandate of again assisting those who are in need of help. Through its International Open Source Network (IOSN) initiative via the Asia-Pacific Development Information Programme (APDIP), the United Nations Development Programme (UNDP) is again enabling those governments who cannot necessarily create their own ICT ecosystem, by helping to reduce costs.

Governments throughout the world are and will remain cash challenged. In the USA, healthcare costs are increasing 8 to 15 percent a year, with much of that burden falling on both the states and the federal government. Emerging nations and mature governments throughout the world face the same daunting challenges. The UNDP, through its IOSN initiative, will enable widespread adoption of Free/Open Source Software (FOSS) and create at least one avenue for nations to deal with the "unsustainable cost of government."

FOSS, based on Open Standards, provides governments with a sustainable and sufficiently robust software model that fosters collaboration and ever-increasing innovation. In addition to the obvious cost advantage for acquisition, the ongoing operational expense will also contribute to lowering the cost of government. By engaging the worldwide open source community, governments can benefit from each others' efforts and share applications that each have built. Remember, every government does the same things: collects taxes, provides assistance to those citizens in need, register births, deaths, marriages and motor vehicles, houses prison inmates and issues drivers' licenses. So why do individual governments continue to build applications on their own and most often do a very poor job of it? By incorporating the best tenets of FOSS, increased collaboration and innovation, governments working together can create meaningful value for their citizens and for each other.

At no time in modern history has it been more important than now for governments to band together and foster meaningful information exchange. And in this age of information and communications technology, standards and the means by which standards are set become vital. The attributes of open standards and the model for establishing open standards are what will allow for sustainable information exchange, interoperability, and flexibility. Where public funds are concerned, adopted standards should be vendor neutral and open to all to implement without royalties. Otherwise citizens will not be able to consume information produced by the government without having to purchase or pirate software.

FOSS mimics the ubiquity of the Internet and can transcend geographic and political boundaries. Its communal nature unites humanity, helps bridge our numerous divides, and can continually contribute to closing the digital divide.

UNDP's IOSN efforts through FOSS, open standards, and open content represents the best of its mission and legacy. We should all applaud and support this extremely important agenda.

Peter J. Quinn

Former Chief Information Officer

Commonwealth of Massachusetts

title: FOSS Open Standards/Foreword


text:
FOSS Open Standards/Preface

This primer is part of a series of primers on Free and Open Source Software (FOSS) from IOSN serving as introductory documents to FOSS in general, as well as covering particular topic areas that are deemed important to FOSS such as open standards. Open standards are not the same as FOSS. However, like FOSS, they can minimize the possibility of technology and vendor lock-ins and level the playing field. They can also play an important role in promoting the interoperability of FOSS and proprietary software and this is crucial in the current, mixed Information technology (IT) environment. Being a primer in the IOSN FOSS series, the issues concerning open standards are approached from the FOSS and software perspectives and emphasis is given to the relationship that some of these standards have with FOSS.

The definition of an open standard has generated much controversy with regard to whether it should contain patents licensed under reasonable and non-discriminatory (RAND) terms. The FOSS community, in general, is of the view that such RAND-encumbered standards should not be considered as open standards but most of the standards development organizations and bodies do accept patents available under RAND terms in their standards. The primer has incorporated definitions of open standards from both sides and also put into perspective the minimal characteristics that an open standard should have.

It is hoped that this primer will provide the reader with a better understanding as to why open standards are important and how they can complement FOSS in fostering a more open IT environment. As users and consumers, the readers of this primer should demand from their software, conformance to open standards as far as possible. In addition to promoting interoperability and making more choices available, this will make it easier for FOSS to co-exist and take root in environments filled with proprietary software.

Nah Soo Hoe

title: FOSS Open Standards/Preface


text: FOSS Open Standards/List of Acronyms

title: FOSS Open Standards/List of Acronyms


text:
FOSS Open Standards/Introduction

What are Standards and Why are They Important?
The word "standard" has several different meanings. Working within the context of the subject matter of this document, its meaning in everyday usage, can be taken to refer to:
 * 1) a level of quality or attainment, or
 * 2) an item or a specification against which all others may be measured.

In technical usage, a standard is a framework of specifications that has been:
 * 1) approved by a recognized organization, or
 * 2) is generally accepted and widely used throughout by the industry.

For the rest of this document, unless specified otherwise, when the word standard is used the technical meaning is implied.

Standards are extremely important in modern society. They ensure that products and services are of adequate quality and that they can interoperate and work together even though they may be from different parties or entities. Ultimately, they raise levels of quality, safety, reliability, efficiency and interoperability, and provide such benefits at an economical cost.

In the IT industry, standards are particularly important because they allow interoperability of products, services, hardware and software from different parties. Without standards, users may be forced to use only hardware and software or services from one party or vendor. Internationally recognized standards define common interfaces and any changes or modifications in the standards are usually carried out by common agreement. For example, the Internet would not achieve its current ubiquitous presence, where it is accessible from almost any type of computer platform and device, if it did not use widely accepted technical standards in its networking infrastructure and supported services.

Open Standards
Having defined what standards mean in general and technical usage, let us turn our attention to the main focus of this primer - open standards. There are many differing opinions on what constitutes open standards.

Definition of Open Standards
Well-known Open Source exponent Bruce Perens argues that an open standard is more than just a specification, and that the principles underlying the standard and the practice of offering and operating the standard are what make the standard open. He proposes that open standards should follow the principles of availability, and maximize end-user choice. In addition, there should be no royalty, no discrimination, extension of subset and predatory practices, and certain practices should be followed to ensure that these principles are adhered to. The Perens definition has found wide acceptance among the FOSS communities worldwide.

The Open Standards Policy of the State of Massachusetts, USA defines it as specifications for systems that are publicly available and are developed by an open community and affirmed by a standards body. The European Commission's European Interoperability Framework (EIF) adds on the requirements that open standards should be available either for free or at a nominal charge for usage, copying and distribution and any patents present are to be made irrevocably available on a royalty-free basis, and there should be no constraints on the re-use of the standard.

Thus, the Perens definition is consistent generally with those of the EIF and the State of Massachusetts, and this approach has gained currency with many policy makers as the basis of their open standards policies.

Other organizations such as the American National Standards Institute (ANSI), the International Telegraph Union Telecommunication Standardization Sector (ITU-T) and the Business Software Alliance (BSA) have also come out with their definitions and policies on open standards. While all of these recognize that open standards have to be publicly available for implementation and participation in development by interested parties, they also recognize the inclusion of essential intellectual property rights (IPR) so long as these IPR can be made available under non-discriminatory terms and for a reasonable fee or for no fee at all.

Thus, we find that while there may be numerous detailed definitions and meanings given to open standards, in general, they all satisfy the following characteristics:
 * 1) easy accessibility for all to read and use;
 * 2) developed by a process that is open and relatively easy for anyone to participate in; and
 * 3) no control or tie-in by any specific group or vendor.

Examples of open IT standards are:
 * 1) the Transmission Control Protocol/Internet Protocol (TCP/IP) suite of networking protocols from the Internet Engineering Task Force (IETF);
 * 2) the Hypertext Transfer Protocol (HTTP) service protocol from the World Wide Web Consortium (W3C) and the International Organization for Standardization (ISO);
 * 3) the Unicode coding standard from the Unicode Consortium and ISO; and
 * 4) the Portable Operating System Interface for UNIX (POSIX) portable operating system interface from The Open Group, the Institute of Electrical and Electronics (IEEE) and ISO.

Many organizations as well as governments are starting to emphasize that their IT usage follow or adhere to open standards as far as possible as they now realize that by implementing open standards they can have more flexibility in their choice of technology, vendor and solutions. In an increasingly complex and heterogeneous IT environment, no single technology or vendor can offer solutions on everything and so the ability to mix and match and to interoperate is of critical importance. Information is now exchanged and stored electronically as never before. It is only by following open standards in the exchange and storage/retrieval of the data that an organization can be assured of access to that data, both now and later when the technology or vendor may be long gone.

It should be noted here that wide usage of a standard does not necessarily mean that it is open. Numerous examples are found in the IT industry (e.g. the Portable Document Format or PDF from Adobe Inc., the Powerpoint presentation file format from Microsoft), where some technology or file/data format associated with a popular product is very widely used, so much so that it becomes a de facto standard, i.e. a standard established through widespread usage and acceptance in the industry. However, because this is very often based on a technology by a specific party (vendor or close group) and is under the control of this party, it does not qualify as an open standard. There are potential pitfalls in adopting this as a standard as there is no open mechanism for the user to participate in its development and no guarantee that the party in control will not try to lock in users into its product or technology. In some cases, the owner of the product/technology may agree to submit it to an internationally recognized standards-setting body and in so doing it may then become an open standard.

At the same time, however, governments and organizations should be open to the possibility that some such de facto standards, like PDF for example, are so widely and reasonably licensed and so broadly deployed that it makes sense to temporarily support such standards as part of a government's or organization's interoperability programme. To completely ignore such standards as a rule may actually impair interoperability, particularly if there is no adequate open standard substitute for such a de facto standard

Open Standards and FOSS
Many people are confused between the terms open standards and FOSS thinking that they are one and the same or one cannot exist without the other. To be consistent with other publications by IOSN, the term FOSS will be used in this document to refer to open-source software and/or free software. Unless otherwise stated open standards is not the same as FOSS, which refers to software that follows certain principles in its creation, modification, usage, licensing and distribution. In particular, it should have the four fundamental freedoms:
 * 1)  freedom to run the program, for any purpose;
 * 2)  freedom to study how the program works, and adapt it to your needs;
 * 3)  freedom to redistribute copies so you can help others; and
 * 4)  freedom to improve the program, and release your improvements to the public.

The FOSS: A General Introduction primer from IOSN may be referred for more background and details on FOSS.

FOSS is software whereas open standards refer to standards - two different things altogether. The processes and issues involved in developing software and a standard are also very different. It is entirely possible for a functionality in a non-FOSS software (often called proprietary software) to be implemented following an open standard. Open standards are neutral with regard to software licensing or business models and so it is equally possible for an open standard to be implemented in proprietary software as  it is in FOSS. For example, proprietary software like the Microsoft Windows operating system can still implement the TCP/IP networking protocols following the open standards from IETF and be compliant with them.

Widespread usage of standards, and especially open standards, is very important to FOSS. It makes it easier for FOSS to be compatible with proprietary software. It is a practical reality that FOSS needs to coexist with proprietary software and that compatibility with the proprietary platforms is facilitated if standards are adhered to by all. If all software products were to follow standards strictly, they should be able to interoperate and communicate among themselves well and data files could be read and written transparently. While both proprietary and open standards may allow this to happen, the latter are preferred by the FOSS community as they facilitate free access, open development and participation.

FOSS support may be difficult in cases where a proprietary specification is not publicly published but needs to be licensed. In the past, one way to work around this problem is to reverse engineer some proprietary product that implements the specification or protocol but, in recent times, more and more proprietary licenses have specifically forbidden this. In some countries, legislation has also been passed (e.g. the Digital Millennium Copyright Act in the USA) that makes it illegal to reverse engineer a product if it is deemed that the process can assist in the circumvention of measures implemented to protect against illegal copying of the product. These developments have re-enforced the important role that open standards play in ensuring that FOSS can interoperate well with proprietary software. The emergence of FOSS and the open standards that it uses highlight the needs and benefits of open standards in a world where interoperability is required.

FOSS has also benefited much from open standards in that the current widespread usage and popularity of FOSS owes much to the Internet and the open standards that the Internet utilizes. While programmers (and many users who write their own programs) have been freely exchanging programs with source code since the early days of the computer, it was only after the Internet explosion in the 1990s that the idea and culture of FOSS became widely known and accepted by the mainstream IT industry. FOSS that implements the open standards and protocols used on the Internet like TCP/IP, HTML, Simple Mail Transfer Protocol (SMTP), etc., were easily available and many people as well as organizations started to use these. From there they became aware of FOSS and the latter grew in strength and acceptance as more and more used it and contributed towards it.

Some may argue that the freedom in FOSS for anyone to modify the software source code will allow and may even encourage the inclusion of code that does not conform to published standards. This is possible but in practice it is seldom done (i.e. modifying a FOSS mainstream product to make it non-compliant with an open standards and redistributing the modified software). Also FOSS project owners guard against this as they realize that it is to the advantage of FOSS if open standards are adhered to as much as possible. In fact, it is very natural for FOSS to promote the adoption of open standards since the ideals and development model of FOSS itself encourages availability, openness and participation by all - the very traits and characteristics of an open standard.

Focus of the Primer
This primer is part of a series of primers on FOSS from IOSN serving as introductory documents to FOSS in general, as well as covering particular topics that are deemed important to FOSS in greater detail. As such, the issue of open standards is approached from a FOSS perspective and emphasis is given to the relationship that some of these standards have with FOSS. While open standards are available and important for both hardware and software, the examples and references given in this primer focus mainly on standards related to software.

title: FOSS Open Standards/Introduction