text:
User:John G.~enwikibooks

I am working on the the Piano wikibook and the TI-Basic wikibook.

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

title: User:John G.~enwikibooks


text:
Piano/Rests

In this diagram are shown the seven different types of rests used in musical notation for pianos.

1. The rest with the 1 underneath is known as a big rest. This name is easily remembered with the fact that the rest drops under the line on the staff, making it a "hole". This rest takes up an four beats of music, the size of the standard measure.

2. The rest with the 1/2 underneath is known as a half rest. It consists of two beats, generally half a measure.

3. The rest with the 1/4 underneath it is a quarter rest. It consists of one beat, or one fourth of a standard measure.

4. The rest with the 1/8 underneath is known as an eighth rest. it consists of 1/2 of a beat, or 1/8 of a standard measure.

5. 1/16 – 16th rest; 1/4 of a beat, 1/16 of a measure

6. 1/32 – 32nd rest. rarely used. 1/8th of a beat, 1/32 of a measure

7. 1/64 – 64th rest. rarely used. 1/16 of a beat, 1/64 of a measure.

The 1/32 rest and 1/64 rest are rarely used in most pieces, with the exception of some slow pieces or pieces with irregular time signatures.

title: Piano/Rests


text:
Operating System Design/Processes/Scheduling

Because only one process per CPU can run at any one time, multitasking operating systems use a concept called multiprogramming to schedule time for each process to run on a CPU. A scheduler is responsible for giving each process time on the CPU. When the current time slice expires, the scheduler puts the current process to sleep and the next process is given CPU time. Some scheduling systems include:
 * First Come First Served
 * Shortest Process Next
 * Shortest Remaining Time
 * Round Robin Scheduling
 * Pre-Emption
 * Priority Scheduling

Schedulers for early batch mainframe systems and many modern servers often focus on maximizing throughput. Schedulers for real-time operating systems often focus in minimizing latency and guaranteeing that deadlines are always met (see Embedded Control Systems Design/Real Time Operating systems. Schedulers for modern desktop operating systems try to balance fairness, throughput, and latency (see The Linux Kernel/Processing).


text:
User talk:John G.~enwikibooks

Feel free to leave your comments here.

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called John G.. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name John G.~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:17, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:05, 19 April 2015 (UTC)

title: User talk:John G.~enwikibooks


text:
User:Pvpurcell

Hi There I'm new to the wikiworld and trying to learn the ropes. anything helpfull you have to say or even some constructive critisism, don't worry I have a thick skin! Some would even comment a thick skull to! Ha ha ha!

title: User:Pvpurcell


text:
User talk:Pvpurcell

Hello and welcome to Wikibooks!

Here are some tips to help you get started:
 * You can sign your name on Talk and vote pages using four tildes, like this: ~~~~.
 * Remember to conduct any editing experiments in the sandbox.
 * Check out our help page if you need additional help.
 * Eventually, you might want to read the Manual of Style and Policies and Guidelines.
 * Take a look at Naming policy
 * See list of templates which can save your time
 * Remember to maintain a Neutral point of view.
 * Explore, be bold in editing pages, and have fun!

You can find more resources in the Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, or the IRC channel.

Good luck!.--Az1568 01:39, 19 September 2006 (UTC)

RE: Thanks
I saw your note, and I wanted to thank you for your kind comments. Another user has left you some useful links above here, so I won't take the time to repeat them all. However, if you want to ask a question, you can feel free to ask it on my talk page, where you left your earlier note (i usually respond quickly on weekdays), on you can ask at the Staff Lounge, which is a central discussion forum for our project. Also, when you type a message, you can type four tildes (" ~ "), and the server software will automatically insert your username in the form of a "signature". This way, people know who wrote what.

If you need anything at all, please let me know. --Whiteknight (talk) (projects) 02:14, 19 September 2006 (UTC)

title: User talk:Pvpurcell


text:
Talk:Organic Chemistry/Alkenes/Naming alkenes

In the case of butene, I have never heard that a double bond on the 1 carbon does not need to be numbered. What does everyone else think? MiltonT 02:12, 19 September 2006 (UTC)

 * Sounds dodgy to me too. but-1-ene and but-2-ene I think Ewen 15:19, 14 November 2006 (UTC)


text:
Operating System Design/Scheduling Processes/Priority Scheduling

In Priority Scheduling, each process is given a priority, and higher priority methods are executed first, while equal priorities are executed First Come First Served or Round Robin.

There are several ways that priorities can be assigned:
 * Internal priorities are assigned by technical quantities such as memory usage, and file I/O operations.
 * External priorities are assigned by politics, commerce, or user preference, such as importance and amount being paid for process access (the latter usually being for mainframes).

SPN is a form of priority scheduling based on External Priorities.

Analogy
Internal: At a store, the person with the right change and only two items gets to check out first. External: At a store, the cashier is bribed by the most important customer, who can thus check out first.

Advantages and Disadvantages
A process can sometimes become starved, live locked, or indefinitely blocked. One way to fix this is by aging the priority, so that the longer a process has waited for CPU time, the higher its priority is.


text:
Basic Physics of Nuclear Medicine/Fourier Methods

Fourier methods are described below in quite general terms. We will see that any waveform can be broken up mathematically into sine waves of different amplitudes and frequencies using the Fourier transform. We will also see that the resulting Fourier Spectrum can be modified to enhance and/or suppress frequencies of interest. The aim of this exercise is to treat the Modulation Transfer Function (MTF) and the filtration stage of the tomographic image reconstruction process in greater detail than previously.

Periodic Functions
A periodic waveform, is a function which repeats itself regularly over a given interval of time or space. A good example is a sine wave or a square wave. When the waveform fluctuates with respect to time, the wave can be characterised by its frequency (see the figure below), which is defined as the number of cycles passing a given point each second. Frequency is expressed in units of cycles per second, or hertz (Hz). A good example of such a periodic waveform in medicine is the electrocardiogram (ECG).

When the waveform fluctuates with respect to distance (see the following figure), the wave is characterised by its spatial frequency, which is defined as the number of cycles per unit distance, e.g. cycles per mm.

A medical imaging example of this latter type of fluctuation is the Pb bar pattern which is widely used to determine the spatial resolution of an imaging system (see the following figure). In this case, the spatial frequency is expressed in, for example, line pairs per mm, since each section of Pb and its adjacent void is referred to as a line pair.

Fourier Series
Almost all periodic functions of interest in medical imaging can be represented by a Fourier Series. This approach considers that any periodic waveform can be represented by the sum of a series of sine and cosine waves as follows:

$$f(x) = \frac{1}{2}a_0 + a_1 \cos (x) + a_2 \cos (2x)... + a_n \cos (nx) + b_1 \sin (x) + b_2 \sin (2x)... + b_n \sin (nx)$$

A square wave, for example, can thus be represented by:

$$f(x) = \frac{4h}{\pi} \left ( \sin (x) + \frac{1}{3} \sin (3x) + \frac{1}{5} \sin (5x) + \frac{1}{7} \sin (7x) + ... \right )\ \ (1)$$

where h is the amplitude of the square wave.

The opposite consideration is also true mathematically, i.e. a square wave can be constructed by adding together a large number of sine waves of different frequencies and amplitudes. The addition of the first four terms of equation (1) is demonstrated in the following figure. The first term (sin x) is shown in panel (a), the addition of the second term to the first term is shown in panel (b) and so on. Notice that the fundamental, or first harmonic [panel (a)], has the same frequency as the square wave and that the higher frequencies progressively build up the shape of the square waveform [panels (b)-(d)]. We can conclude that the higher frequencies contribute to the sharpness of the sides of the square wave.

Fourier Spectrum
The Fourier Series can also be represented as a frequency spectrum. For example, the amplitudes of the frequency components for the square wave in equation (1) are plotted against spatial frequency in the following figure. Note that the Fourier Spectrum can be used to identify the frequencies and amplitudes of the sine waves which contribute to make up a given waveform. Note also that plots of amplitude versus distance are generally referred to as the spatial domain representation, and plots of amplitude versus spatial frequency as the frequency domain representation.

Fourier Transform
The Fourier transform is an elegant mathematical technique for converting data from the spatial domain to the frequency domain (see the next figure). In other words, the frequencies and amplitudes of the sine waves which make up any waveform can be readily determined by taking the Fourier transform of that waveform.

The Fourier transform is used widely throughout medical imaging, where its applications include:
 * determining the spatial resolution of imaging systems,
 * spatial localisation in magnetic resonance imaging,
 * analysis of Doppler ultrasound signals,
 * image filtering in emission and transmission computed tomography.

The Inverse Fourier Transform is the mathematical technique used for coverting data in the opposite direction, i.e. from the frequency domain to the spatial domain – see the following figure:

In conclusion, the Fourier Transform (FT) allows us to identify the component sine waves of a waveform, and the Inverse Fourier Transform (IFT) allows us to construct a waveform from its component sine waves.

Finally, it should be noted that the computation of Fourier Transforms using a digital computer is generally achieved using a special algorithm called the Fast Fourier Transform (FFT).

The Dirac Delta Function
An interesting case to consider from a medical imaging perspective is the delta function:

The Fourier Transform of the Dirac delta function tells us that it is composed of an infinite number of sine waves, each of the same amplitude. If we begin to broaden this function – as in the following figure – we see that the low frequency sine waves have a high amplitude and that the amplitudes of the sine waves decrease as the spatial frequency increases:

Modulation Transfer Function
This broadening phenomenon is similar to what happens in medical imaging. We can consider the amplitude versus distance plot in the previous figure to be similar to a:
 * density profile through an image of a small hole in a sheet of Pb, or a
 * count rate profile through an image of a point source of radioactivity.

This type of plot is called a Point Spread Function (PSF) in medical imaging, and its Fourier Spectrum is called the Modulation Transfer Function (MTF):

A comparison of general and imaging terms used in this field is shown in the following table:

In addition, the MTF may be derived from:
 * a Line Spread Function (LSF)
 * a differentiated Edge Response Function (ERF).

Symbolically, we can write:

$$I_{\text{actual}} = I_{\text{ideal}} * PSF\,\!$$

where $$*$$ indicates a convolution operation. In other words, the actual image is obtained when the ideal image is convolved with the PSF of the imaging system.

To restore the ideal image, all that is required theoretically is to remove the effect of the PSF (e.g. attempts to solve imaging problems encountered by the Hubble space telescope). This can be achieved readily using the Fourier transform because the convolution process in the spatial domain is equivalent to a multiplication process in the spatial frequency domain, i.e.

$$FT(I_{\text{actual}}) = FT(I_{\text{ideal}}) \cdot FT(PSF)\,\!$$

and therefore,

$$FT(I_{\text{ideal}}) = \frac{FT(I_{\text{actual}})}{FT(PSF)}$$

The complete restoration process is referred to as a deconvolution operation and is given by:

$$I_{\text{ideal}} = IFT \left \lbrace \frac{FT(I_{\text{actual}})}{FT(PSF)} \right \rbrace$$

Filtering the Fourier Spectrum
The image restoration process discussed above is an example of Fourier spectrum filtering. In other words, once a Fourier Spectrum has been generated for an image, it can be filtered so that certain spatial frequencies can be modified, e.g. enhanced or suppressed. This filtered spectrum can then be inverse transformed to generate a filtered image with, for example, sharpened or smoothed features – as illustrated in the following figure:

An example is shown in the following figure in the case of a bone scan of the hand. Its 2D FFT is shown in the top right panel. The result of applying a filter which suppresses spatial frequencies below 0.05 cycles/pixel and above 0.3 cycles/pixel, i.e. a bandpass of 3-20 pixels, is shown in the centre row of the figure, while that of a filter which suppresses frequencies below 0.01 and above 0.1 cycles/pixels in shown on the bottom row.

A feature we need to consider in more detail before proceeding is the spatial frequency nature of the image data itself. Remember that images are generally sampled digitally using a square matrix composed of pixels, the size of which dictate how well a digital image approximates its analogue counterpart. The resultant digital spatial resolution places a limit on the maximum spatial frequency that can be accommodated. The criterion usually applied in digital imaging is based on the Nyquist-Shannon Sampling Theorem which implies that:

When an image has spatial frequency components with a maximum spatial frequency, f, then the image data should be sampled with a sampling frequency of at least twice f for faithful reproduction.

This sampling frequency is commonly called the Nyquist frequency. At lower sampling frequencies, the resultant digital images can contain artefactual patterns, called Moiré patterns, and the phenomenon is sometimes referred to as aliasing.

Filtered Back Projection
The streaking inherent in the simple backprojection process makes the actual image appear as if it had been combined mathematically with a 1/r function, where r is the radial distance in the Fourier domain. In filtered backprojection, Fourier filtering can be used to remove the effect of this $1/r$ blurring.

Symbolically, a measured projection can be considered to be the result of a convolution with a blurring function:

$$P_{\text{measured}} = P \cdot \frac{1}{r}$$

The first stage of the filtration process is to calculate the Fourier transform of the measured projection data, i.e.

$$FT(P_{\text{measured}}) = FT(P) \cdot FT \left ( \frac{1}{r} \right )$$

The corrected projection, P, is then obtained by dividing the FT of the measured projection by FT($1/r$), and taking the inverse transform of the result, i.e.

$$P = IFT \left \lbrace \frac{FT(P_{\text{measured}})}{FT \left ( \frac{1}{r}\right )} \right \rbrace$$

The FT($1/r$) function is simply that of a ramp. In other words, when the FT of the measured projection is calculated and the result is divided by this ramp function, then the corrected projection can be obtained by calculating the IFT of this quotient.

In addition, if some variation is introduced into the FT($1/r$) function, it is possible to simultaneously correct for this blurring effect and to enhance or suppress features in the back-projected image. For example, the blurring artifact can be removed and, at the same time:
 * the fine detail can be enhanced (as in the so-called bone algorithms in X-ray CT), or
 * the image noise can be suppressed (as in the so-called soft tissue algorithms in X-ray CT).

In general, variation in the ramp function can be achieved by multiplying it by a second function, e.g. a Butterworth function used in SPECT:

$$\text{Amplitude} = \frac{1}{1+(\frac{f}{f_c})^{2n}}$$

where:
 * fc: cut-off frequency, which defines the frequency at which the amplitude drops by 50%, and
 * n: the order of the function.

Characteristics of a number of filters used in SPECT imaging are shown in the following table:

Note that x in the equation for the Metz filter is called the power factor, and that S in the Wiener filter equation is called the shape factor.

The choice of filter for a given image reconstruction task is generally a compromise between the extent of noise reduction and fine detail suppression (and of contrast enhancement in some cases) as well as the spatial frequency pattern of the image data of interest.


text:
Adventist Youth Honors Answer Book/Vocational/Internet

a. Internet
A collection of approximately 60,000 independent, inter-connected networks that use the TCP/IP protocols and that evolved from ARPANet of the late '60s and early '70s. "The Net," is a worldwide system of computer networks providing reliable and redundant connectivity between disparate computers and systems by using common transport and data protocols.

b. World Wide Web (WWW)
Though World Wide Web (or simply Web for short) is a term frequently used (incorrectly) when referring to "The Internet", it has two major meanings: First, loosely used: the whole constellation of resources that can be accessed using Gopher, FTP, HTTP, telnet, USENET, WAIS and some other tools. Second, the universe of hypertext servers (HTTP servers), more commonly called "web servers", which are the servers that serve web pages to web browsers.

c. Chat Room
A site on the World Wide Web where any number of computer users can type in messages to each other (chat) in real time, creating an online conversation. These messages usually appear on an area of the screen next to the user's nickname or handle (your online nickname or the name you go by in a chat room). Most chat rooms have a particular topic (which you are expected to discuss) but there are some that are purely for meeting other people.

d. Download
To copy a file from a remote computer to your computer. There are a few methods of doing this on the Internet. HTTP, FTP and e-mail attachments are the most common. This term is also used when referring to moving pictures from a camera or other image device to a local computer.

e. Upload
To move a digital file (such as a media file) from a local system to a server where it is stored for others to access or later retrieval. For example, web pages must be "uploaded" to a web server for them to be viewed on the World Wide Web. The terminology for "upload" and "download" comes from the days of satellite communications. When an earth-bound terminal send data to the remote computer (the satellite), it was uploaded, as the direction of data travel was up. When the terminal received data from the satellite, it was downloaded, as the direction of data travel was down.

f. Website
One or more files (pages) stored on a computer (a "server") that can be accessed via the Internet. Every website has a "home page", which is generally designed as the file visitors first see when coming to the site and which gives an idea of the site's contents. All files on a website usually contain textual or graphical "links" that can be clicked using an input device such as a mouse to move to other files, either within the site or on another one.

g. Email
Email is similar to personal letters, only a lot faster. Email is used to send messages via your computer to friends and acquaintances around the world. Requires a computer, email software, an email account through an Internet Service Provider (ISP) and a modem. Technically, email (electronic mail) is the exchange of computer-stored messages by telecommunication. Most email messages usually contain text, but you can also send non-text files, such as graphic images and sound files as attachments. Email accounts for a large percentage of the total traffic over the Internet. An email address is easily identified by the '@' symbol, for instance webmaster@pathfindersonline.org, making identification of the domain it's attached to much easier - in this case pathfindersonline.org

h. Virus
Throughout this honor, the term “virus” represents the traditional virus, as well as trojans, worms, and other malicious code.

 * Traditional virus: In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. Thus, a computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of the virus into a program is termed infection, and the infected file (or executable code that is not part of a file) is called a host.

 * Trojan: named after the Trojan horse used by the rescuers of Helen of Troy. A Trojan is a computer program that disguises itself as a useful software application that is actually used to gain access to your computer.

 * Worm: A computer worm is a self-replicating computer program. It uses a network to send copies of itself to other nodes (computers on the network) and it may do so without any user intervention. This is due to the poor security the computers infected have. Unlike a virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

a.Webmail / POP3 / IMAP mail
All are methods / techniques for reading email.
 * Webmail: Webmail is a web application that allows users to read and write e-mail using a web browser. Examples: Hotmail.com, yahoo.com and many other online services offer you the option to view your email from their website.  This is "webmail."

 * POP3 mail: Post Office Protocol 3. A protocol that provides a simple, standardized way for users to access mailboxes and download messages to their computers. Examples:  Outlook Express, Outlook, Eudora, Mozilla Thunderbird*

These examples are accurate as of 10/2005. Please check Google.com or other search service to verify the accuracy of these examples currently.
 * IMAP: Internet Message Access Protocol'. IMAP is a method of distributing e-mail. It is different from the standard POP3 method in that with IMAP, e-mail messages are stored on the server, while in POP3, the messages are transferred to the client's computer when they are read. Thus, using IMAP allows you to access your e-mail from more than one machine, while POP3 does not. This is important because some email servers only work with some protocols. Example:  AOL is an IMAP mail provider, though they also offer webmail services.*

b. Web browser
A program used to view, download, upload, surf or otherwise access documents (pages) on the World Wide Web. Browsers can be text-based meaning they do not show graphics or images but most however are text and graphical based. Browsers read "marked up" or coded pages (usually HTML but not always) that reside on servers and interpret the coding into what we see "rendered" as a Web page. Examples:  Microsoft Internet Explorer, Mozilla Firefox, and Netscape Navigator are examples of Web browsers.

c. IRC/IM (Instant Messenger) client
Internet Relay Chat. A live chat area of the Internet in which real-time conversations among two or more people take place via special software. Each specific IRC channel begins with a # and is dedicated to a different area of interest. IRC is considered another part of the technology of the Internet the same way FTP, Telnet and the Web are.

An instant messenger is a client which allows instant text communication between two or more people through a network such as the Internet.

Examples include Windows Messenger, AOL Instant Messenger, ICQ client, Yahoo Messenger, and Jabber, as well as software programs that allow you to talk to friends on multiple “messenger” platforms simultaneously.

d. Streaming Media
Video or audio transmitted over a network that users can begin to play immediately instead of waiting for the entire file to download. Typically a few seconds of data is sent ahead and buffered in case of network transmission delays. (Although some data is buffered to the hard drive, it is written to temporary storage and is gone once viewing is complete.) RealMedia, QuickTime and Windows Media are the most common streaming formats.

e. Search Engine & Search Directories
Internet search engines (e.g. Google, Bing) help users find web pages on a given subject. The search engines maintain databases of web sites and use programs (often referred to as "spiders" or "robots") to collect information, which is then indexed by the search engine. Similar services are provided by "directories," which maintain ordered lists of websites, e.g. Yahoo!

f. Antivirus software
A computer program designed to detect and respond to malicious software, such as viruses and worms. Responses may include blocking user access to infected files, cleaning infected files or systems, or informing the user that an infected program was detected. Such tools should be included as part of the computing systems environment that the web services are delivered from. Examples include Norton Antivirus, McAfee Antivirus, Trendmicro Antivirus. Online FREE antivirus tools includes Trendmicro's Housecall, and freea-v.com.

1. These software programs are leaders in antivirus technology as of 10/2005. Please check with online resources or local computer/office supply stores for the latest versions and programs available.
 * Note: Many of these companies also offer "Internet Security Suites" that assist the user in also blocking and removing trojans, worms, malware, and other malicious code.

g. Firewall
A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

Examples include: ZoneAlarm, Microsoft Firewall, Norton Firewall, and many other free and for-pay packages.

a. Write a brief 250-300 word history of the Internet.
Include date/events surrounding its origin, the major landmark events, the birth and growth of web browsers (such as Mosaic, Netscape, Internet Explorer), and what it is doing today. Remember, this is not a history of computers, but rather a brief history of the Internet. You should list at least 2 online resources from which you found information relevant to your report.

b. Present a 2-3 minute talk concerning the history of the internet.
If you choose this option, you will need to present the same information as in option a. It's OK to use notecards during the oral presentation so that you can follow your outline and not have to memorize dates and other facts.

a. What are some ways you can receive viruses via the Internet?
when you open an attached file in the email you received from unknown contact or even in chain email/message via internet. you also get viruses by clicking advertisements with pop-ups on your browsers. And you also get virus if you download any files that contains virus from the internet.

b. How is having up-to-date antivirus software important for keeping your computer files safe?
having up-to-date antivirus software is important, because it helps us keep tract of new viruses that our computer might get from the internet. if our antivirus software is updated, our files are kept safe.

c. How can not being protected lead to sharing the virus with other family and friends?
we might share a file to our friends or family through an email or device without knowing that the file contains virus. the virus might damage our friends or family's computer or even thumb drive that we use to share files that might contain virus.

d. What harm can a virus do to your computer or to other people’s computers?
Viruses can damage your files in the computer including software. Some viruses spread to other computers.

Many viruses completely take over the computer they infect and can be remotely controlled by the attacker. These attackers can then use the computer to send spam, or mount a Distributed Denial of Service (DDoS) attack against their target's web server or computer network. Sometimes these viruses record keystrokes on the infected computer so that they can capture usernames, passwords, and bank account numbers. This information can then be forwarded to the attacker who can either use the information or sell it to someone else.

==5. In what ways do content filters(programs like Net Nanny™ or AOL Parental Control) protect your family? With your family, develop & sign a Covenant of Family Internet Usage including the following elements==
 * a. Never reveal personal information
 * b. Remember that people may not be who they say they are.
 * c. Never meet an online friend in the flesh for the first time without a parent present.
 * d. Never respond to flames
 * e. Stop immediately if you see or read anything that upsets you.
 * f.Time each member of the family may spend on the internet per week. Set boundaries that encourage time for family, homework, and other necessary family activities.
 * g. Types of websites that are acceptable/unacceptable to view. What are the principles that your family will use to determine what are acceptable? Base these principles on the Bible.

An agreement ready to sign has been prepared for you on the third page of the pdf of the Internet Honor requirements on the Pathfinders website: http://www.pathfindersonline.org/pdf/ayhonors/internet_a.pdf

a. Visit at least 3 different websites (distinct domain names). Print out the front page of each site for your instructor.
To save paper, it is recommended that rather than printing hard-copies of web pages, that the Pathfinder open the three web pages in separate tabs in the browser. A tab can be opened usually by right-clicking on the link and selecting the "Open page in another tab" option. In Firefox, clicking the link with the center mouse button (or using both the left and right buttons at the same time) will open the page in a new tab. Once three tabs have been opened, the instructor can check that the requirement has been met on-screen, without printing anything.

===b. Demonstrate your ability to use a search engine to find an online Bible website. Go to the website, look up at least 3 different Bible memory texts in 3 different versions, and print your results for your instructor. Also, find 3 websites that talk about the Seventh-day Adventist Church. Print out the front page of each site for your instructor.===
 * i. http://www.biblegateway.com is a great online bible resources, as is http://www.blueletterbible.org.
 * ii. There are thousands of quality Adventist websites, many of them referenced at http://www.plusline.org.  Quality sites of interest to young adventists include:
 * http://www.pathfindersonline.org
 * http://www.adventist.org
 * http://www.guidemagazine.org
 * http://www.kidsbibleinfo.com.

c. Download a compressed file from the internet (tar, zip, etc.) to your hard drive and uncompress it and operate the program or file.
pcmagazine.com church websites such as http://plusline.org, http://iiw.org, and http://adventist.org
 * i. Please use safe sites to download from, such as CNET’s download.com

d. Know 5 principles of operating email safely.

 * 1) Do not reply to unknown emails or Spam. You're simply verifying that yours is a “real” email address and you will immediately receive even more junk email.
 * 2) Do not open emails with attachments unless you are SURE that they're okay, and that your antivirus program is fully updated (most are auto-updated these days).
 * 3) Report any material sent to you in email that is unsafe or that you feel breaks God's laws.
 * 4) Never respond to "unsubscribe" directions in a spam or UCE (unwanted commercial email) message.
 * 5) Keep your computers operating system patches up to date. If you're using Windows, do this from the MS Windows Update site using the Windows Update function.

8. Memorize Philippians 4:8. How does this Bible text guide a Christian’s use of the internet?

 * “Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable——if anything is excellent or praiseworthy——think about such things.” Philippians 4:8

Some questions to guide a small group discussion on this text:
 * 1) What do you think the writer, the apostle Paul, would say this text meant for internet users today?
 * 2) What do you think God had in mind when he asked Paul to write down this text?
 * 3) What are some things on the internet that you make use of that match (are consistent with) this Bible text?
 * 4) What are some of the things that are on the internet that do not match (are inconsistent) with this Bible message?
 * 5) Why do you think this text is important to Christians today?
 * 6) What are some ways that we as a club can help each other apply this text to our daily lives?
 * 7) What do you think are some ways we can live lives that match (are consistent) with this text?

About the Author
| /Completed Honors


text:
Afrikaans/Lesson 01

= Lesson One: The Basics #1 — Les Een: Die Grondbeginsels #1 = Welcome to Afrikaans Lesson One. This course will focus heavily on translation and reading in order to further your knowledge in a shorter span of time. In far later lessons, we will start the lesson with the dialogues, but for now, we shall start with the grammar of the language. The chapter vocabulary section is where one can find the stress markers of words that appear throughout the lesson. Still, if you still need to practice basic Afrikaans pronunciation or need to get familiar with the idea of stress markers, we recommend using the Pronunciation page. This lesson will cover similarities between English and Afrikaans, the use of articles, subject and object pronouns, and infinitive and present tense verbs.

I. Similarities Between English and Afrikaans
As both Afrikaans and English stem from the West Germanic family, obvious similarities exist in syntax, vocabulary and word formation. This fortune allows for Afrikaans to be a simple language for English speakers to grasp.

Spelling Comparison
Apart from direct cognates, spelling patterns can be ascertained too. Though none of these rules are etched in stone and each word should be studied carefully, these commonalities definitely make acquiring certain Afrikaans words much easier. Any word here indicated with a stress marker does not need immediate attention is not necessary, while some without a stress marker will reappear latter in this lesson.
 * The English suffix, -tion, often translates to the Afrikaans suffix, -sie.
 * Examples: poˈsisie (position), ˈaksie (action), konˈdisie (condition)
 * Some monosyllabic Afrikaans words containing the letter, g often correspond to an English, y. This trend continues with the particularly noticeable Afrikaans adjectival suffix, -ig.
 *  ' G ' Examples: geel (Yellow), dag (day), weg (way), vlieg (to fly), oog (eye)
 *  ' -ig ' Examples: ˈheilig (holy), ˈsonnig (sunny), ˈysig (icy), ˈbesig (busy)
 * Some Afrikaans words beginning with sk-, are akin to English, sh-.
 * Examples: skip (ship), ˈskaduˌwee (shadow), skoen (shoe)
 * If there are words that are the same in both languages, an English hard c is usually equivalent to an Afrikaans k with few exceptions:
 * Examples: kamoeˈflage (camouflage), kalaˈmari (calamari)

II. Determiners: Articles
The definite article in English is the, which in Afrikaans, is die.
 * "Die man." ('The man.'); "Die kind." ('The child.'); "Die rivier in die woud." ('The river in the forest.')

English's indefinite article, a/an both become ŉ (pronounced as [ ə]) in Afrikaans. Whenever a sentence begins with the indefinite article, the spelling rule associated declares that the noun, proper noun or adjective that directly follows must be capitalized.
 * "ŉ Vrou." ('A woman.'); "ŉ Tafel." ('A table.'); "ŉ Seun en ŉ meisie." ('A boy and a girl.')

A. Subject Pronouns (Nominative Case)
Afrikaans, like English, follows a simplistic SVO (Subject - Verb - Object) word order. The subject of a sentence refers to who/what is doing an action.

 * I know him. → Ek ken hom.

Though the subject rules are essentially the same as in English, there are two things to note on formality of conversation:

 * 1) When in an informal context, julle and hulle can be shortened to jul and hul.
 * 2) * They talk to him. → "Hulle praat met hom." is the same as "Hul praat met hom.", though the latter is more informal. (NOTE: speak/talk to → praat met)
 * 3) The formal, u (pronounced as [ œ]), functions like a plural, but refers to both singular and plural. This form is used to show respect and is used toward one's superiors (a boss or teacher, for instance), to a stranger, to older people or to the Christian God. When in reference to the Christian God, it is capitalized as U.

B. Object Pronouns (Oblique Case)
The object of a sentence describes who/what the action is directed towards. Unlike German or Russian, Afrikaans, like English, does not distinguish between the Direct Object (Accusative Case) and Indirect Object (Dative Case). Thus, all objective pronouns remain the same.
 * I know him. → Ek ken hom.

It should be noted that every plural object pronoun (including u) is the exact same as its subject form.
 * She forgets you. → Sy vergeet u.
 * He understands them. → Hy verstaan hulle/hul.

IV. Practicality: Greetings and Phrases
Afrikaans greetings are used in the exact same contexts as English ones, though with more attention to formality. When in an informal context, you might greet someone with a "haai" rather than a "hallo" or a "goeiedag". For instance, goeienaand is used when greeting a person during the evening while goeienag is used when leaving; No different from English.

A small thing to note is that the 'Good [x]' forms below exist as one word when posed as an interjection/greeting (Good afternoon! = Goeiemiddag!), but the form becomes two words when talking about a good part of the day (It was a good afternoon.' = "Dit was ŉ goeie middag.").

In later lessons, the different given forms in the notes will be expounded on and will make sense to the learner (eg. Why Good becomes Goeie). For now, just learn the forms as given.

The Infinitive
The infinitive, sometimes referred to as the verb's 'dictionary form', is formed in English by adding 'to' before the verb's present participle. The infinitive is the form of a verb without a subject or specific tense.

 * to walk, to sleep, to eat.

In Afrikaans, the infinitive form is formed by adding 'om te' before the participle.

 * om te loop, om te slaap, om te eet.

The Present Simple and Present Continuous
Fortunately, Afrikaans has extremely simple conjugation. If you look at every present form in every countable person, you will notice that the verb and its participle NEVER change. There is no direct distinction between verb forms of the present simple or present continuous.

 * I (am) eat(ing) an apple. → Ek eet ŉ appel.
 * I (am) sleep(ing). → Ek slaap.

However, it must be noted that there are literal ways to describe the continuous, and we shall cover it in future lessons. Another thing to know is that there are two very common verbs that deviate completely from the conjugation's common ruleset: "om te wees" (' to be ') and "om te hê" (to het' '), which we'll cover in the next lesson.

VI. Chapter Vocabulary
This is the chapter's main vocabulary. By the next chapter, you should well know these words as they are all quite common. Still, one should take note of the example words used in the grammatical explanations and try to keep them in mind as they will appear in the exercises too.

VII. Chapter Dialogues
Almost every lesson, two different dialogues related to the material of the lesson is provided to get the learner familiar with the material at hand. Having reviewed this lesson's notes, you should be able to understand the grammatical structure. If you must look at the vocabulary and its stresses above or at the translation below, do so as sparingly as possible.

Exercise A: Translate into English:
Translate these sentences into English.
 * Goeienaand en goeienag.
 * Die dag is sonnig.
 * Die woud is mooi in die somer.
 * My naam is Japie, en hier is my vriend, Valerie.
 * Hul werk op ŉ skip.
 * Waar is my ander skoen?
 * Een, Vyf, Nege, Ses, Sewe, Twee

Exercise B: Translate into Afrikaans:
Translate these sentences into Afrikaans.

 * Hello, my name is Sally. Pleased to meet you.
 * The river is icy in the winter.
 * The madam lives here.
 * You (plural) eat an apple.
 * We are sleeping.
 * Hi! Where is the boss?
 * You (formal) see him.

The Next Lesson
In the next lesson, we shall cover plurals, the past and future tenses, the verbs "om te wees" and "om te hê" and possessive pronouns and determiners. Good luck on your studies! On to Lesson Two!>>

title: Afrikaans/Lesson 01


text:
GIMP/Gaussian Blur

The Gaussian Blur filter blurs an image or selection. The radius affects the strength of the blur. Besides for creating a fuzzy image, the Gaussian Blur has a few other uses. If you are working on an image with edges which one deems to be overly rough, one could use a blur radius of 1 to soften the image slightly, yet less dramatically than using a larger radius or the standard Blur filter. It is also very useful for a variety of image effects, such as shadows.

IIR vs. RLE
The filter supports two methods of Gaussian Blur: IIR and RLE. They both produce the same results, but each one can be faster in some cases. IIR (Infinite Impulse Response) works best for large radius values or for images which are not computer generated, such as photographs. RLE (run-length encoding) works best for computer-generated images or those with large areas of constant intensity, such as logos.

Selective Gaussian Blur
The Selective Gaussian Blur filter will selectively apply a Gaussian Blur to areas of a picture with less detail, leaving the areas with detail untouched. This can be used for cleaning up noise in a picture.

title: GIMP/Gaussian Blur


text: User talk:202.32.178.40

title: User talk:202.32.178.40


text:
Intermediate Algebra/Slope

To find the slope of a line you have to use the graph:

With two points (x1,y1) and (x2,y2),

$$m = (y2 - y1)/(x2 - x1)$$

An example of this is to find the slope of the two points (4,3) and (8,5).

$$m = y2(5) - y1(3)/x2(8) - x1(4)$$

$$m = 5 - 3 / 8 - 4$$

$$m = 2/4$$

$$m = 1/2$$

Therefore, the slope of those two points is 1/2. Now to graph the slope of a line you use the formula:

$$y = mx + b$$

Where b = the Y-Intercept and m = the slope of the line.

But first we must find what the Y-Intercept is, to do this we choose one of the points that we are given, and input it into the formula. For this example, I'm going to use the point (4,3):

$$y (3) = m(1/2)x(4) + b$$

$$3 = 1/2(4) + b$$

$$3 (+2) = 2(-2) + b$$

$$5 = B$$

We now have the Y-Intercept, this can then be input into the formula to find the various points to graph. Using a simple T-Chart, pick various numbers and substitute them in for X, and you will find Y. Write these down, and graph them.

x = 0

$$y = m(1/2)x(0) + 5$$

$$y = 1/2(0) + 5$$

$$y = 5$$

x = -2

$$y = m(1/2)x(-2) + 5$$

$$y = 1/2(-2) + 5$$

$$y = -1 + 5$$

$$y = 4$$

x = 2

$$y = m(1/2)x(2) + 5$$

$$y = 1/2(2) + 5$$

$$y = 1 + 5$$

$$y = 6$$

X - Y

0 - 5

-2 - 4

2 - 6

Plot the points, and connect the dots to form your line.

Now a shortcut to doing this is to use the rise over run (Rise/Run) formula. Which is simply that whatever the slope is, (In the case of our example, 1/2) is the rise and run of our slope.

The rise is how many up from our Y-Intercept we go before we plot our point. The run is how many left or right (X-Axis) we move before we plot our point. So if we have a slope of 1/2, our Rise is 1 and our Run is 2. This means that we move 1 (one) up from our Y-Intercept and 2 (two) to the right (since 2 is a positive number, if it were -2 we would move to the left on the X-Axis). So our plot would be at (6,2), and the next point after that would be (7,4) and so on.

Rise/Run format is much easier and faster, but you should still understand how to use a T-Chart.

title: Intermediate Algebra/Slope


text:
Horticulture/Phytophthora infestans

Phytophthora infestans is a water mould, that causes the serious disease of the potato, late blight or potato blight. (Early blight, caused by Alternaria solani, is also often called potato blight). This disease was a major culprit in the causation of the 1847 Irish potato famine and also the Highland potato famine. The organism can also infect tomatoes and some other members of the Solanaceae.

The spores of this water mould overwinter on infected tubers, particularly those that are left in the ground after the previous year's harvest, and are spread rapidly in warm wet conditions when blight can have devastating effects, destroying entire crops.

Spores develop on the leaves, spreading through the crop when temperatures are above 10°C and humidity is over 75% for 2 days or more. Rain can wash spores into the soil where they infect young tubers, or else spores can be blown in from distances of up to miles by the wind.

The early stages of blight are easily missed, and not all plants are affected at once. Symptoms include the appearance of dark blotches on leaf tips and plant stems. White mould will appear under the leaves in humid conditions and the whole plant may quickly collapse. Infected tubers develop grey or dark patches that are reddish brown beneath the skin, and quickly decay to a foul-smelling mush caused by the infestation of secondary soft bacterial rots. Seemingly healthy tubers may rot later when in store. Up until the 1970s, there was only one type of blight (A1) in the UK, and this was unable to produce resistant spores that could survive the winter. There are now two types (A1 and A2) which can mate and after that produce resistant spores, although the indications so far are that this rarely, if ever, happens in the UK. Mating can occur only between moulds of different mating-types and is required for the production of resistant spores.

Prevention and control of potato blight can be achieved by planting only good quality seeds obtained from certified suppliers. Do not save your own seed for replanting, and try to ensure that no ‘volunteer’ tubers are left in the soil after harvest. Potato varieties vary in their susceptibility to blight. Most early varieties are very prone; so that the crop matures before blight starts (usually in July) plant them early. Maincrop varieties which are very slow to develop blight include Cara, Stirling, Teena, Torridon, Remarka and Romano. Some so-called resistant varieties can resist some strains of the blight and not others, so their performance may vary depending on which are around.

Growing potatoes should be earthed up regularly in order to minimise the risks of spores being washed down into the soil reaching the tubers. If blight symptoms appear, remove all affected leaves immediately. Cut off and burn all foliage in bad cases to help prevent spread to the tubers. Don't harvest the crop for at least 3 weeks. By then, tubers will have thicker skins and blight spores on the surface will have died. A hot compost heap should destroy the spores on the leaves, but it is probably not worth the risk. Any infected tubers should definitely be burned.

The potato blight caused the Irish Potato Famine in 1845-49 which, it is estimated, caused over 1,000,000 to starve death and forced a further 2,000,000 to emigrate.

title: Horticulture/Phytophthora infestans


text:
Talk:Horticulture/Phytophthora infestans

Transwiki notes
Copied from this version] of Phytophthora infestans, 08:46, 19 September 2006 (UTC)


text: User talk:80.96.203.106

title: User talk:80.96.203.106


text:
Basic Physics of Nuclear Medicine/Patient Dosimetry

This chapter overviews the MIRD method of estimating doses in nuclear medicine and gives results of surveys of typical patient doses for a small range of examinations. Doses from X-ray CT surveys are also given for comparison purposes, and to aid with your appreciation of the dosimetric impact of PET/CT and SPECT/CT.

MIRD Calculations
The direct measurement of the absorbed dose to organs of the body from nuclear medicine procedures is rarely possible. Most estimates depend on Monte Carlo simulation. To compute a dose distribution, many hundreds of thousands of virtual gamma rays originating in numerous source organs must be traced through the body as they interact with tissues by Compton scattering and photoelectric absorption. Contributions to the dose from Auger electrons, internal conversion electrons and beta decays must also be included This latter part of the simulation is usually quite straight-forward since these radiations can be considered to be absorbed in the organ they originate in.

The Medical Internal Radiation Dose (MIRD) Committee in the USA has provided a substantial body of data to assist in dose estimation. The MIRD method of calculation allows estimation of the dose to organs of significance from radioactivity distributed homogeneously throughout a particular source organ. The method can be split into two parts:

 * Firstly, some assumptions are made about or measurements are taken of the biological distribution of radioactivity throughout the body, taking into account both the biological and physical half-life of the labelled radionuclide.

 * The cumulated activity, Ãs, in any particular source organ is calculated by integrating the instantaneous activity over time. This data might be obtained from theoretical modelling (such as Compartmental Analysis) or from measurements using a gamma camera to measure the count rate as a function of time in the organ of interest - see the following figure:

 * Mathematically, this type of activity/time curve can be represented by the equation:

$$\tilde{A}_s = \int A_s (t) \cdot dt$$

 * where As(t) is the activity in the source organ, s at time, t.

 * Secondly, the absorbed dose to a target organ, Dt, is calculated from:

$$D_t = \sum_{s} \tilde{A}_s \cdot S(t,s)$$

 * where the summation over s is intended to account for contributions from all source organs to the target organ. The S-factor, S(t,s) is the mean absorbed dose to the target organ, t, from unit activity of the relevant radioisotope distributed homogeneously within the source organ, s.  Note that its possible for the source and target organ to be the same entity.

The S-Factor
The challenging part of the MIRD method is the calculation of the S-factor because it depends on accurate knowledge of the radiations emitted by the radionuclide. Although the MIRD publications assist by providing representative values of S-factors for most organs and for a variety of radionuclides, it is important to understand the methodology and hence the limitations of this technique.

The S-factor for each radiation type can be broken down into component factors:

$$S(t,s) = D \frac{f(t,s)}{m}$$

where:
 * D is a measure of the total energy associated with the particular radiation type and is a physical entity known from the radioisotope's decay scheme,
 * f(t,s) is the absorbed fraction for the particular radiation emitted in the source organ, s, and absorbed by the target organ, t, and
 * m is the mass of the target organ.

The absorbed fraction represents the fraction of the total energy emitted by radiation of a particular type that is absorbed in the target organ. For beta particles, which have a short range in tissue, it can be assumed that all the energy will be deposited in the source organ and other target organs will not be irradiated. That is:

$$f(t,s) = 0\,\!$$

Unless t = s, in which case:

$$f(t,s) = 1\,\!$$

The determination of the S-factor is very simple in this case.

For gamma-rays, however, no such simple approach is possible since the amount of energy deposited in the source organ and in the target organ is dependent on:
 * the gamma ray energy, as well as
 * the size, shape and separation of the two organs in question.

Furthermore, we need to take into account not just the gamma-rays from the nucleus of the radioisotope but also emissions from the whole atom, i.e. emissions resulting from the electron shells when stimulated by emissions from the nucleus. The situation for 99mTc is illustrated in the following table, as an example:

We can see in the table that a range of radiations are generated within the atom as a whole. For instance, on the first line the energy of a gamma-ray emitted by the nucleus is given to an M-shell electron in about 75% of one type of isomeric transition giving it a maximum energy of 1.63 keV, i.e. about 1.2 keV per nuclear disintegration. On the second line, a gamma-ray resulting from another isomeric transition in 89% of instances emerges unscathed from the atom with an energy of 140.5 keV, or about 125 keV per disintegration. In a third case, in about 9% of these latter isomeric transitions, an electron in the K-shell gains energy of 119.5 keV, which is sufficient for it to overcome the binding energy (about 21 keV) of that shell and leave the atom. Notice that fluorescent X-rays, resulting from electronic transitions to fill vacancies in the K-shell are also produced - as well as Auger electrons.

Part of a resultant MIRD table of S-factors for 99mTc is reproduced below as examples of typical values:

The unit of the S-factor is typically mGy/MBq/hour. Note that substantial discrepancies between actual and calculated values can be expected depending on differences in anatomy and physiological function between individual patients.

The Dose in a Liver Scan
To illustrate how the table above can be used in a hypothetical situation, suppose a liver scan is performed in which 37 MBq of 99mTc-labelled sulphur colloid is administered to a patient. Suppose also that it is found from metabolic modelling that:
 * 80% of the cumulated activity goes to the patient's liver and
 * 20% goes to their spleen.

When it is then assumed that the biological half-life for the colloid is infinite in these two organs, which is a reasonable approximation, the calculation of cumulated total activity is much simplified as illustrated in the box below:

 * {| class="toc" style="background:transparent; text-align:left;"

 * rowspan="5" style="vertical-align:top; padding-right:5px;" | $$\tilde{A}_{\text{liver}}$$
 * $$= \int A(t) \cdot dt$$
 * $$= \int A_0\ \text{exp} \left ( \frac{-0.693t}{T_\frac{1}{2}} \right ) \cdot dt$$
 * $$= A_0 \cdot 1.44 \cdot T_{\frac{1}{2}}$$
 * $$= 0.8 \cdot 37 \cdot 1.44 \cdot 6.03 \cdot \text{MBq.h}\,\!$$
 * $$= 256.6\ \text{MBq.h}\,\!$$
 * rowspan="2" style="vertical-align:top; padding-right:5px;" | $$\tilde{A}_{\text{spleen}}$$
 * $$= 0.2 \cdot 37 \cdot 1.44 \cdot 6.03\ \text{MBq.h}\,\!$$
 * $$= 64.1\ \text{MBq.h}\,\!$$
 * rowspan="2" style="vertical-align:top; padding-right:5px;" | $$D_{\text{liver}}\,\!$$
 * $$= (1.2 \cdot 10^{-2} \cdot 256.6) + (2.6 \cdot 10^{-4} \cdot 64.1)\ \text{mGy}\,\!$$
 * $$= 3.2\ \text{mGy}\,\!$$
 * }
 * rowspan="2" style="vertical-align:top; padding-right:5px;" | $$\tilde{A}_{\text{spleen}}$$
 * $$= 0.2 \cdot 37 \cdot 1.44 \cdot 6.03\ \text{MBq.h}\,\!$$
 * $$= 64.1\ \text{MBq.h}\,\!$$
 * rowspan="2" style="vertical-align:top; padding-right:5px;" | $$D_{\text{liver}}\,\!$$
 * $$= (1.2 \cdot 10^{-2} \cdot 256.6) + (2.6 \cdot 10^{-4} \cdot 64.1)\ \text{mGy}\,\!$$
 * $$= 3.2\ \text{mGy}\,\!$$
 * }
 * rowspan="2" style="vertical-align:top; padding-right:5px;" | $$D_{\text{liver}}\,\!$$
 * $$= (1.2 \cdot 10^{-2} \cdot 256.6) + (2.6 \cdot 10^{-4} \cdot 64.1)\ \text{mGy}\,\!$$
 * $$= 3.2\ \text{mGy}\,\!$$
 * }
 * }

Note that the liver dose arises almost exclusively from the presence of radioactivity in the liver and that the activity in the spleen contributes little to this dose - just 5%.

In similar way, the dose to the spleen can be calculated to be 5.8 mGy. Note that even though less activity accumulates in the spleen the absorbed dose is higher. This apparent paradox can be resolved however when you recall that the absorbed dose is the energy absorbed per unit mass.

The International Commission on Radiological Protection (ICRP) have published more accurate organ absorbed doses derived on the basis of knowledge of physiological data for what is known as the Reference Man and from the MIRD data. Note that the absorbed doses to the liver and to the spleen in the following table are 2.74 and 2.85 mGy, respectively - somewhat lower than we calculated in our simple, hypothetical situation above.

Note that an effective dose of 0.35 mSv can be obtained by summing the values in the right hand column of the table.

Finally, note that a radiation weighting factor, wR, of unity has been assumed for simplicity throughout the above discussion for all the radiation energies arising from the decay of 99mTc.

Typical Nuclear Medicine Doses
The following table lists the effective dose from a number of nuclear medicine procedures (adapted from ICRP 53):

Note that typical effective doses from 99mTc scans are of the order of a few mSv. Also note the high effective dose from a 201Tl scan - arising in part because of the high uptake of activity in the testes - and also those from 67Ga and 131I. The administered activities listed in the table are consistent with the most commonly used activities found in a survey of Australasian Nuclear Medicine practices conducted in 2000.

Typical Doses in X-Ray CT
The radiation dose delivered to the patient in X-ray CT is determined by factors which include the radiation energy and intensity characteristics, the size of the patient, the efficiency of the radiation detectors as well as factors derived from the specific form of image acquisition used (axial versus helical scanning, for example).

The absorbed dose is far from uniform within the patient - being greatest at the skin and a factor of about three lower in the centre of the irradiated region. Typical values for skin absorbed doses range from about 5 mGy to 50 mGy. Head scan absorbed doses are usually higher than body scan doses because of the substantial attenuation in the skull. In addition, the lens of the eye can receive a relatively large dose, typically 50 to 100 mGy, and if repeat examinations are undertaken the deterministic limit for cataract induction may be exceeded. Protocols, using appropriate gantry angulation, should be developed to minimise the possibility for direct irradiation of the eye. Likewise, relatively large uterine doses may arise from abdominal or pelvic CT scans and this may be a concern in scanning women of child bearing age.

A number of surveys have been published in recent years in which the effective dose from CT scans have been estimated - see the table below. The data indicates that the effective dose is typically 2 to 20 mSv with the higher values relating to CT scans of the abdomen and pelvis and the lower values relating to the head and cervical spine. This variation is largely a reflection of the number of radiosensitive organs that may be irradiated by the primary beam. The dose variation between countries is a different matter!

Notice that effective doses from nuclear medicine procedures are of a similar order of magnitude, but generally lower, than that from CT examinations. To assist with your comparison: the effective dose from a chest X-ray is about 0.02 mSv, while that from a mammogram is about 0.4 mSv and from an intravenous pyelogram (IVP) its about 3 mSv. How does this last figure compare with the dose from a renogram? You might like to speculate on the reasons for the large difference as an exercise to further develop your understanding of this topic.


text:
Template:Phytopathbox

Do not edit this template unless you know what you are doing.

/Templates/Boxes

title: Template:Phytopathbox


text:
Template:Phytopathbox/Examples

Using Template:Phytopathbox
This template is automatically included by the page template.

Example
/Templates/Examples

title: Template:Phytopathbox/Examples


text:
User:Dorch

My name is Søren Bertil Fabricius Dorch. I am a research librarian (subject specialist) at Copenhagen University Library (the Royal Library) and an honorary associate professor at the Niels Bohr Institute (Copenhagen University). My research subjects are within astrophysics: Cosmic magnetic fields and stellar dynamo action. I am a huge fan of Star Trek (and Editor of the Danish Star Trek fanzine "Subspace").

Links

 * My page in Danish Wikipedia
 * My research webpage

title: User:Dorch


text:
Flute/Breathing

Breathing is extremely important in playing any wind instrument. One cannot hope to achieve a strong sound and proper phrasing without good breathing.

Basic Breathing
First, stand or sit up straight. Think about a string attached to the top of your head like a marionette pulling you up. If your upper body is not straight, it will restrict your breathing. Posture is very important.

When most people think about taking a deep breath, they only think about filling up their chest. For good breathing, think about how a person breathes when they are sleeping. If you watch a person sleep, you will notice that their belly expands, rather than their chest. A proper deep breath involves expanding at the belly first, with the movement of the diaphragm, the main muscle used in breathing.

So, first you will inhale and expand your belly. At first this may not be very much, but after practice your capacity will increase. After expanding your belly, breathe in even further to expand your chest. Then exhale, allowing your chest and belly "deflate". That is the basis of breathing.

One way to experience this: Exhale all the air in your lungs, and then allow your lungs to inhale by themselves. You should feel your stomach take the breath.

Practice Breathing
There are a number of ways you can practice your breathing:
 * Get a balloon and practice inflating it over and over again.
 * With your flute, play a single note and try to hold it out as long as possible while you time yourself. Stop timing when your flute stops making sound. Record how long you were able to hold the note. You will notice that the time gets longer as you regularly practice.
 * Using your diaphragm, yell out "Ha!" repeatedly to practice the strength of your muscles. It is important to use your diaphragm to make the sound rather than your throat. With the same diaphragmatic push, you can also practice this on your flute.

Circular Breathing

Circular breathing is an additional technique which make a tone continuous without pause, accomplished by the use of the cheeks as a reservoir of air while breathing through the nose rather than the mouth.

title: Flute/Breathing


text:
The Grand Inquisitor

This book is an annotated text for 3 noteworthy chapters from Fyodor Dostoevsky's book The Brothers Karamazov. The three chapters considered here are The Grand Inquisitor, Rebellion, and The Devil, which are considered to be some of the most powerful chapters from the book, and some of the most influential chapters in the canon of western literature. Eventually this book could be expanded to include other chapters from this book, although it is unlikely that the entire book will ever be annotated here.

These three chapters revolve around Ivan Karamazov, an educated intellectual and admitted atheist in Russia. The first two chapters also include Alyosha Karamazov, a counter-point to Ivan, who is a monk in training, and is well known for his qualities of compassion, unconditional love, strong faith, and trustworthiness.

Table of Contents

 * /Introduction/

Background

 * /History/
 * /Fyodor Dostoevsky/
 * /The Brothers Karamazov/
 * /Characters/

Text

 * /Rebellion/
 * /Rebellion (Part 2)/
 * /The Grand Inquisitor/
 * /The Grand Inquisitor (Part 2)/
 * /The Devil/
 * /The Devil (Part 2)/

Appendices

 * /Resources/

title: The Grand Inquisitor


text: User talk:81.208.36.81

title: User talk:81.208.36.81


text:
Map This!

This Wikibook intends to provide an exhaustive guide to Map This!, is an open source homebrew satellite navigation application for the Sony PlayStation Portable. In combination with a GPS receiver it allows you to see where you are on a map. Map This! can also function as a simple map viewer without a GPS receiver.

It is currently (13:09, 23 January 2008 (UTC)) based on Map This! version 0.5.20. The official site of Map This! is http://deniska.dcemu.co.uk/.

You can see Map This! in action here: http://www.youtube.com/watch?v=9U33zXTOh14.

There are also two Map This! forums:
 * Deniska's Discussion Forum: http://www.dcemu.co.uk/vbulletin/forumdisplay.php?f=170
 * Deniska's News Forum: http://www.dcemu.co.uk/vbulletin/forumdisplay.php?f=105

Besides Deniska, other people have worked on Map This! as well. Some of the functionality other people have written has made it into the official version (notably MIB.42's changes), while other functionality was released in unofficial versions.

One of the first unofficial versions, by atari800, added sound features to Map This!. This version has now been taken offline.

Another unofficial version, by Nieko, added a.o. auto map switching, auto zooming, and GPS recording to POI. This version can be found on.

Contents

 * /Requirements/
 * In order to get Map This! working you will need the following:

 * /Installation and setup/
 * This section covers everything concerning files you can put on your memory stick in order to run Map This!. You do not need to follow all steps, but if you want, you can.

 * /Operation/
 * When you've completed the installation, it's time to start Map This!. This section assumes Map This! is functioning properly. If you encounter problems, see Troubleshooting.

 * /Tips and tricks/
 * Several users have reported tips & tricks regarding Map This!.

 * /Troubleshooting/
 * /Can I?.../
 * A few questions on the limits and possibilities of Map This!

 * /Legacy support/
 * In older Map This! versions there are a few things that worked differently. If you want to update to a newer Map This! or want to run an older version, take a look at the following changes.

title: Map This!


text:
Talk:Formal Logic/Sentential Logic/Informal Conventions

Association of connectives

 * We will let a series of the same binary connective associate on the right. For example, we can transform the official

 * $$(\mathrm{P^0_0} \land (\mathrm{Q^0_0} \land \mathrm{R^0_0}))\,\!$$

 * into the informal

 * $$\mathrm{P} \land \mathrm{Q} \land \mathrm{R}\ .\,\!$$

 * However, the best we can do with

 * $$((\mathrm{P^0_0} \land \mathrm{Q^0_0}) \land \mathrm{R^0})\,\!$$

 * is

 * $$(\mathrm{P} \land \mathrm{Q}) \land \mathrm{R}\ .\,\!$$

Is this correct? Why can't it be written as

 * $$\mathrm{P} \land \mathrm{Q} \land \mathrm{R}\,\!$$

? --193.196.13.2 17:20, 19 September 2006 (UTC)

Sorry to be slow to respond. The two formulae

 * (1)   $$(\mathrm{P} \land \mathrm{Q}) \land \mathrm{R}\,\!$$
 * (2)   $$\mathrm{P} \land (\mathrm{Q} \land \mathrm{R})\,\!$$

are equivalent (both are true if and only if all three conjuncts are true. However, our rules state that we associate otherwise ambiguous formulae such as

 * (3)   $$\mathrm{P} \land \mathrm{Q} \land \mathrm{R}\,\!$$

(where all the connectives are the same) on the right. Thus only (2) disambiguates (3) according to our rules. Suppose we write (1) as (3) and then disambiguate. The result is (2), thus making our abbreviation rules inconsistent.

We could have written the rules differently. We could have written the rule so as to associate on the left. Nothing much rides on our decision since the truth condidtions for (1) and (2) are the same. But if we are going to have some abbreviations, we need to pick a set of rules and stick to it. --JMRyan T E C 21:13, 2 October 2006 (UTC)


text:
User talk:Kharr050

By: Kelby Harris

Encourageing The students who need encouragement the most are often the least  likely to receive it. Timothy Evans Encouragement is an essential element inside and outside the classroom. In the classroom encouragement should be practice everyday. It is important for every child to feel encouraged even when they don't understand something that is taught. Every teacher should be equipped with the knowledge of knowing how to display encouragement towards his/her students to motivate them. It is very important to survey and interview students about their thoughts, opinions, and feelings about how the teacher is operating the class. This will help the teacher get a better idea of what is effective and what is not. Feedback from your students will help you understand how they are feeling about your class. In college the dean issues out surveys at the end of every semester for each class to fill out. This survey helps to let the college know how effective the professors are and what they need to improve. In intermediate schools, and elementary schools, and high schools this is important as well. I interviewed a sixteen-year-old male student that is currently a sophomore at Great Bridge High School. The interview consisted of five questions on how encouragement is used in the classrooms at his high school. Here are the five questions that were asked and his rebuttals.

1. What does encouragement mean to you? Feeling uplifted when you fail or struggle, something from keeping you from quitting or feeling like a failure. 2. How often do your teachers make you feel encouraged on a scale 1-10 (1 being the lowest and 10 the highest)? Four. 3. What class are you most encouraged in? Why? ''Spanish II because my teacher tells us encouraging things when we stumble over pronunciations of words. For example she says, "Don’t quit you can do, it I know it."'' 4. How do you feel when you are encouraged? It actually motivates me to work harder rather than give up because I don’t understand. 5. Do you think it is important to have your teachers be encouraging to their students?  I think it is very important because, it mentally prepares you to think you can do anything that you put your mind to.

When teachers focus more on the efforts made by their students rather than the improvements that need to be made it is more encouraging to both the teacher and student. It is not only the teacher's job to deliver information to the students but to encourage them even when they are having trouble. A teacher can get frustrated easily with his/her students progress. However, it is very important that the teacher subsitutes the frustration with words of encouragement to keep the student from feeling like a failure. Encouragement in the classroom will build positive energy and thoughts to make the student's preformance better. For example,when I was in fifth grade we had a dedicated time every morning for a session called Positive Action. In this session our class was given positive stories of children being encouraged when they were struggling with their studies or an activity they were trying to do. At the end of every story the student successfully completed the task. Still today this impacts me the same way it did in fifth grade. Positive Action in the morning encouraged my class and helped create a strong confident environment for the rest of the day. There are six important steps that should be given to every teacher to help shape their classrooms with encouragement they are; make relationships a priority, conduct respectful dialogue, practice encouragement, make decisions through classroom meetings, resolve conflicts, and have fun. Those are steps that should be conducted in the classroom, but there are also a variety of steps that should be left out of the classroom such as; setting very high expectations, focusing on mistakes to try to motivate, comparing your students, making pesstimistc interpretations, and being to helpful. These five suggestion of things to keep out of the classroom enviornment will help tremendously. A fine line is drawn between encouragement and praise. Teachers should be able to distinguish the differences between them. Praise stimulates rivalry and competition, fosters selfishness at the expense of others, focuses on quality of performance, and fosters failure. However, encouragement fosters acceptance of being imperfect, encourages student to not give up, fosters self-suffieciency and independence, and stimulates cooperation and contribution. An easy way to distinguish between praise and encouragement is to be able to identify praise comments and encouraging comments. A general praise comment would be "You are the best student I have ever had," or " You had the highest score on this exam in the class" compared to an encouraging comment, " You are a fine student any teacher would appreciate and enjoy you" or" You did very well on this exam." The danger of giving praise to a student after everything he/she accomplishes puts them at a high risk of feeling like a failure if praise isn't rewarded to them in everything. Also, students who are oftened praised don't accomplish things for themselves, but for the satisfaction of others waiting for their rewards of praise. It is critical to make sure you are using the correct phrases when encouraging your students. The two are easily confused when used, but it is critical to use the correct phrases to let your student know that you a proud of their efforts even if they fail. Encouragement can be used in all areas of life. At T.R. Simons Elementary School in Alabama, the lunchroom staff issues an award of the week to the class that uses manners during lunch. Frequently the monitors are encouraging the students to use manners while eating and encourage those who are doing well. Every class eventually receives an award encouraging everybody as a whole. This is an effective way of encouraging students outside the classroom. Students not only feel better about their efforts in accomplishing something, but are more motivated to do it again later.

title: User talk:Kharr050


text:
User talk:70.161.239.190

Is it your own user page you are editing? If yes, please log in. --Derbeth talk 18:17, 19 September 2006 (UTC)
 * Please stop editing User:Kharr050. --Derbeth talk 18:46, 19 September 2006 (UTC)

title: User talk:70.161.239.190


text:
College Survival Guide/Improving Reading Skills

Read the Course Books Before the Semester Starts
Many college students have this policy after learning "the system" to read the course books ahead of time. Of course, this proposes many questions:

 * What am I suppose to be learning from this book?

Answer: Whatever is covered in the book. All things covered that relate to the course are important. Remember as much as you can about a book, while knowing which gibberish to ignore. Often, when reading a book with a lot of information, much of the information to remember belongs to specific people/objects, events, actions, results, locations, concepts, and problems. This " thing to remember logic " applies to multiple academic disciplines.

Either way, most "good" college students come out of a course remembering about 50% of the material covered in a course book.
 * When the class starts, you can ask your professor about what is to remembered and what is not.

Here's something to remember: read as much of a/the book(s) as you can, as soon as you can. Read a/the book(s) before the semester starts.

"Reading before the semester starts" technique: Say, you have five books and one book for each course.

Read at least 10 pages from each book. When you are done with 10 pages from one book, switch to the next book; keep this 10 page revolving system going, until classes start or read a chapter and then switch books. Usually, reading one chapter from a book and switching to the next does well for covering the book(s) of each class. Some people get annoyed with studying one thing, so they'll switch to the next book after a certain amount of pages. If you have a certain major, say psychology, you'll probably be able to retain and read more pages than from other books: This may or may not be a good idea.

By keeping up a certain pattern of reading each book, you will be able know what the books cover and what the class topics are about.

Try to read as much of each book as you can before classes start. You will have an advantage if you read the books ahead of time.

Write Down What You Don't Understand
When a person reads a book he or she may have trouble understanding the concepts of the things presented. Often, a person wants to read a chapter, but he or she may continue to try and understand a concept before moving to the next page.

The best thing to do in this situation is to write down the concept you do not understand. After you write down what you do not understand, present what you don't understand to the professor.

Before presenting, find a way to ask about what you don't understand. Write a question about the concept in question form on a piece of paper. This way, when you talk to the professor, you can ask him or her the question about the topic you don't understand, that is on the piece of paper.

Example:

You read a paragraph about RNA, introns, and extrons. Yet you don't understand how introns are cut out from RNA before becoming mRNA.

 * Write down: introns, RNA, and extrons
 * Make a question: How are introns cut out from RNA before RNA becomes mRNA?

After doing so, you may move onto the next page and hopefully understand more as you continue to read. Sometimes as a person moves on, he or she will find different material that is unrelated, so he or she can focus on that material, and later on the part he or she did not understand. With the part someone did not understand he or she would present that question to the professor.

This is a technique used to cover the rest of the chapter, and read the chapter instead of having a point in which someone becomes stuck on a page before moving on.

Highlight what you don't understand
If you have a problem reading something but you can absorb the other information, you might want to highlight certain sections that are giving you problems. Otherwise, you could type these things in a word-processor. Afterwards, you could print them out and later highlight the things you don't understand. Afterwards, you could print another sheet of these things out and highlight the things you still don't understand. Highlighting allows a person to focus on material that is not understood. It allows a person to skip portions of a text that are understood, thus eliminating the need to reread things.