text:
General Astronomy/What People do in Astronomy

Astronomy like all sciences is a social activity in which people are constantly discussing new ideas, interpreting data, and arguing with each other over what observations mean. Astronomers can broadly be divided into two groups. Observational astronomers specialize in building instruments such as telescopes, and spacecraft, and take raw data and process them into meaningful results. Theoretical astronomers often also known as astrophysicists take the results that observational astronomers provide and attempt to create physical models which explain the data that observers see and provide ideas of the directions that observers should go into. Theoretical astronomers increasingly rely on computer models and often are skilled at programming.

Astronomy is rather unique in that a lot of the data is provided by amateur astronomers. The data needed in some fields such as variable star astronomy or comet discovery can be gathered by instruments well within the budget of an interested hobbyist.

Peer review
A central part of the scientific process is peer review which occurs at several stages in the process, and creates what H.H. Bauer calls a knowledge filter. In the peer review process, a proposal or a journal article is given to a group of referees who anonymously submit their comments on the proposal. While the referees will sometimes communicate with each other, they are not intended to reach a consensus on the quality of work. In addition, the referees usually do not have the final authority to decide on the fate of a proposal, but instead given their opinions to an editor or project director who does have the final authority and on occasion overrides the opinions of the referees.

The opinions of the referees are usually made available to the submitter, and often contain suggestions for improvement to the submitter. This is considered crucial for the scientific process as it allows the submitter to receive feedback on his or her proposal and improve it. In some cases, the submitter is encouraged to resubmit their proposal after making changes, and this often develops into an anonymous communication between the referees and the submitter.

Getting what you need
A lot of the work in astronomy involves getting access to resources, which include:

 * money
 * for observers, telescope and equipment time
 * for theorists, computer time

In order to get these resources, astronomers typically write grant proposals which outline the amount of money, telescope, and computer time needed.

Grant proposals typically undergo peer review by the granting agency which includes feedback on how well it fits the priorities of the funding agency, how likely the committees think it is to advance the frontiers of knowledge, and how essential the resource being allocated is to the researcher. Typically, a set portion of telescope or supercomputer time will be made available to the institution that hosts or funds the resource, giving scientists affiliated with that institution priority use over that resource. The remaining time is then made open for research proposals from researchers from other institutions. In the case of ground based telescope time, the most precious and highly sought after time is dark time during which the moon is new and the dimmest objects can be seen.

In some cases, such as building a new telescope, supercomputer center, or funding a new spacecraft, astronomers must lobby funders such as charitable foundations and legislators for money to finance a certain activity. The lobbying for research facilities can be extremely intense as having a facility sited at your institution gives your institution priority access to the facility, as well as prestige, and makes your institution a destination for researchers.

The life of an observational astronomer
Typically, in an observing run, you wake up at about 3 p.m. During the day the technicians will have installed the instruments that you need for a nights observing run. You go to the telescope at 3 p.m., check to see that everything is installed correctly, since you don't want to wake someone up at 3 a.m. if something breaks, you then spend the next two hours before sunset taking some calibration shots.

After the sun starts setting, your first goal is to find the object that you are trying to photograph. You can punch in the coordinates into the computer, but that will only point the telescope in the general area of the sky that you are interested in. The next thing that you have to do is to take out your star atlas, and look for a pattern of stars that is close to the thing that you are looking for. This is a lot like driving in a strange city when you are looking at the monitor and then trying to match the patterns you see with the patterns on the chart.

So you've now found the object you are looking for. In between these measurements, you take some snapshots of a calibration device. If you are looking at spectra, you take picture of a fluorescent lamp that has lines in certain known positions. If you are measuring brightness, then you need to take some pictures of a star whose brightness is known.

So after a night of all of this, you now have some data on hard disk, and you go to sleep. The next few weeks is where the hard part comes in. You see you have a lot of raw data, but it's not very useful to anyone. The problem is that none of the data has been calibrated. So you spend the next few weeks taking the data, subtracting the black levels, correcting the white levels, stretching and shrinking the picture so that you know what the frequencies of your spectra are. You might also be spending your time doing things like trying to correct for the effects of dust in the galaxy. Through it all, you are probably using an astronomy package called IRAF, which like all big software packages has its cute bugs and idiosyncrasies. At the end of all of this you have a paper, and are ready to publish.

Observational astronomers are often at the mercy of things that are outside of their control. Weeks if not months of effort at setting up an observing run can be destroyed if it happens to be cloudy or raining on the night of the run.

The life of a theorist
Unlike observers, theorists are creatures of the day. The typical theorist spends their days reading papers trying to understand how to model a particular type of phenomenon. Once they have a model, the goal then is to try to get testable predictions from that model, and this often means programming a computer to calculate the consequences of that model. There are occasional flashes of inspiration, but most of the time is spent very slowly and methodically trying to understand the consequences of a model, and to slowly and methodically program the model into a computer and systematically remove the bugs from the model.

There are also a lot of social interactions as theorists argue and debate what a particular observation means, and as theorists and observationalists share ideas about the latest data.

Letting people know about your research
There are a number of channels through which scientific results are made known. The primary means that astronomers use to make others aware of current research are through preprints which are papers uploaded through web servers such as the Los Alamos Preprint Server at http://www.arxiv.org/ or through conference proceedings in which scientists announce their results either through lectures or poster papers. Astronomers are also constantly travelling between departments to give talks on their research at seminars, astronomy lunches, and journal clubs.

Although it has been supplemented by preprints, peer reviewed publication in the primary literature is still considered an essential part of publicizing research. This literature consists of articles in journal such as Astrophysical Journal or Astronomy and Astrophysics. Because of the length of time, typically several months, necessary to go through a peer review, research results are typically shared with the community through preprints before peer review is complete. Nevertheless, astronomers still generally submit their papers to peer review even after the results have been released to the research community, because the interaction between anonymous referees and the paper submitter improves the quality of the work and insures the community that the paper does not have any obvious errors.

Once an astronomy paper is available for publication, it can be accessed through the Astrophysics Data System at http://adswww.harvard.edu/ Increasingly, raw data from sky surveys is being made available on the web.

One shortcoming of the primary literature is that it reports on individual research results without providing context. As such it is difficult for someone who is not actively involved in research in a particular area to understand the relevance of the work. To deal with this problem, primary literature is summarized and combined into the secondary literature, where it will be read by a broader audience of scientists. The secondary literature is a synthesis of the results of recent research in a field. The body of secondary literature includes periodic reviews of progress, such as the Annual Review of Astronomy & Astrophysics, professional books, and other research summaries.

How to be an astronomer
Most astronomers major in either physics or astronomy as an undergraduate and then go to graduate school where they work on the Ph.D. under the supervision of a dissertation advisor. The main challenges in becoming an astronomer are to master the language of mathematics and physics, and to gain experience in working through the scientific process.

After graduate school, an astronomer typically works as a post-doctoral fellow before getting a job either as a professor at a university or a researcher at a laboratory. Because of the large number of graduates gaining Ph.D.'s, people with astronomy degrees are increasingly found outside academia. They work in science related fields, as computer programmers for software companies and even on Wall Street.

Astronomy also is open for amateur astronomers. Most of the data for variable stars is accessible via a telescope which is affordable by hobbyists, and amateurs provide important observational data.

Discussion questions
1) Visit either the Los Alamos preprint site or the Astrophysics Data Service and find a paper. How is the paper structured and what concepts in this text book do you find in the papers?

2) Look at the schedule of several university astronomy departments on the web. What is being discussed?  How are different astronomy departments different from each other and how are they the same?


text:
Talk:General Astronomy/What People do in Astronomy

Moved original text here and gradually rewriting.

I don't think that the original text accurately describes the process of astronomy at all. Namely

 * The process of grant writing, isn't and shouldn't be a filter for scientific merit. The main criterion for whether a grant gets issued or not is whether or not the grant proposal meets the institutional priority of the grant writer. If the funding agency thinks that studying quasars is important, then you aren't going to get money to study Jupiter.

 * Most of the communications in astronomy today effectively bypasses peer review. Most of the real communications between astronomers takes place at conferences or via the Los Alamos preprint server.  By the time something is formally peer reviewed, months have passed and it is likely out of date.

 * Review articles are important but it is incorrect to assert that the secondary literature is less error-prone that the primary. Again this is  because things move fast and by the time a review article is written, it is likely out of date.

Roadrunner 00:09, 18 June 2006 (UTC)

 * I disagree with that.
 * The grant process is a filter for scientific merit. I was at the NSF town hall meeting at the last AAS meeting, and Eileen made exactly this point -- scientists shouldn't feel that the NSF isn't interested in their work just because there's no NSF program for their area. Any area of work is eligible and will be evaluated on the basis of merit.
 * It's true that communication usually bypasses the peer review system, but this has always been true. It's still considered necessary to go through the formal peer review process. Keep in mind that peer reviewed journals are as strong now as ever.
 * I'm taken aback by your claim that the secondary literature is no less error-prone than the primary literature, and I'm not really sure how to respond. Journals -- even peer reviewed journals -- are notoriously error prone. I recall reading in Nature some years ago that some 10% of 3-sigma results are eventually discredited. Review articles have the advantage of being written after some degree of consensus and concordance have developed in a field, and these types of problems have been sorted out. And that's exactly what I was getting at.
 * I think the difference in our ideas is that you think of science as a process in which old ideas become obsolete, whereas I see science as a process of iterative clarification on ideas that were previously mostly correct. I'd encourage you read Kuhn's Structure if you haven't already, as well as Bauer's Scientific Literacy and the Myth of the Scientific Method, which is where the peer review filter originates.
 * The bottom line is that the material you're questioning is all grounded in reliable sources. I'm in favor of re-incorporating this.
 * --Brian Brondel 15:44, 18 June 2006 (UTC)

 * I've read Kuhn and I'll take a look at Bauer, but most of my edits involve direct experience with how things work in the trenches. One thing that is significant is that the internet has significantly changed the practice of astronomy.  The other thing that has changed is the *massive* amount of new data that is coming in as a result of WMAP and some of the spacecraft out there.

 * NSF Grants are open to all comers, but if you are at an institution with a telescope you will have priority access to telescope time for reasons that have nothing to do with scientific merit (it's still peer reviewed, but the standard is much lower.) Also, NSF may accept grant proposals for non-program grants, but if the infrastructure isn't there, there isn't much of a chance of getting the proposal funded.

 * Also telescope time (and spacecraft budgets) is so precious that a lot of very good scientific proposals aren't funded for essentially political reasons. The situation is much less bad in astronomy than in particle physics, because the dollar amounts are lower, but I strongly disagree with the idea that the grant process is (or should be) an effective filter for scientific merit because of the high level of politics that inherent in the process.  This isn't a bad thing.  The decision as to whether to risk a space shuttle mission to fix Hubble or how much to fund planetary exploration is essentially a public policy decision, that IMHO shouldn't (and isn't) be made by scientists alone.  It's also the case that the bigger the decision, the less the decision does resemble (or should resemble) the standard peer review process, and the more the decision process resembles (and IMHO should resemble) the legislative process.

 * It is necessary to go through the peer review process for reputation sake, but the primary communications between astronomers is no longer peer reviewed. Things really changed in the 1990's with the Los Alamos Preprint Server.  People have always exchanged preprints, but the Los Alamos server changed things is that now it is impossible for someone in astronomy to do anything useful if they only thing that they read is peer-reviewed articles.

 * In astronomy, the secondary literature is notoriously unreliable because the latest information is not in the secondary literature. In the six months it takes to write a decent review article on the accelerating universe, it is very likely that there is going to be some significant piece of new data that totally invalidates much of the review article.

 * The other thing is that I can point to some review articles that clearly aren't functioning in the way Bauer mentions. There are some very nice articles in Annual Reviews which summarize "non-standard cosmologies" in either neutral or sympathetic ways.  They are excellent introductions to a different way of looking at things (which most astronomers think is nuts), but "error-correction" and "consensus-building" they are not.

 * The problem that I had with article was that it just doesn't fit with what I am seeing, and gives an impression of science that is far more authoritarian than what is actually the case. I do think that Kuhn is very valuable, and I'll need to read Bauer before commenting on his statements.

Roadrunner 16:43, 18 June 2006 (UTC)

--- Given the methods by which scientific progress happens and the potential vulnerability of science to faulty reasoning, it isn't hard to understand why scientific work has sometimes remained in error for many years — sometimes even centuries — before finally being corrected. Paradigms are very valuable to the scientists who work under them, and scientists rarely do their work with complete disinterest and neutrality, but with the specific goal of affirming their own ideas. This inherent and unavoidable bias is the reason an individual cannot successfully engage in science in isolation. The philosopher of science Thomas Kuhn, who is known for his study of the role of the paradigm in science, remarked that "once [a paradigm] has been adopted by a profession ... no theory is recognized to be testable by any quantitative tests that it has not already passed." Progress in science requires practitioners with a variety of viewpoints so that paradigms will be truly tested rather than uncritically reaffirmed.

(...)

To protect against bias in our understanding of the universe, an elaborate system of peer review has become established as a mechanism by which sloppy or incorrect work can be removed. The particular mechanisms of peer review used by modern scientists, named the "Knowledge Filter" by the chemist Henry Bauer, work by applying progressively higher standards to new research.

Unfiltered research begins as an idea. The idea is founded in previous research and the training and world-view or the researcher. The first stage of the filter is the scientist's desire for a good reputation and need for a job. Research must be approved by a panel of respected scientists in order to receive funding. In astronomy, large observatories have committees to allocate telescope time to the projects they perceive to be the best. This first step eliminates obviously wrong ideas from the body of scientific knowledge and allows other ideas to proceed towards acceptance.

Once research has progressed, it is presented to the scientific community again. This is the second filter. As the research is organized into a presentable from, errors are ironed out. The work is again subject to feedback by the community. Before a research paper can be submitted to a scientific journal for publication, it must be submitted to a knowledgeable scientist for criticism. In this step, scholarly publication is protected against poor experimental methods and incorrect conclusions. Work that progresses to this stage appears in primary literature, which reveals the very recent progress and direction of scientific work. The content of the primary literature is, to quote Bauer, "mostly not obviously wrong." It is still subject to scrutiny by the community for correctness and repeatability. The next filter ensures that research lives up to a standard of usefulness. Other scientists apply the results from publication to their own work. As they do this, they also test and extend the original work.

Research that proves itself as useful and influential will be incorporated into the secondary literature, where it will be read by a broader audience of scientists. The secondary literature is a synthesis of the results of recent research in a field. The body of secondary literature includes periodic reviews of progress, such as the Annual Review of Astronomy & Astrophysics, professional books, and other research summaries. In this filter, the opinions of many scientists about the merit of an idea are taken together. Since secondary literature is built upon research that has had time to mature and be tested, the ideas it expresses is more reliable than the primary literature.

As more time passes, the research described in the secondary literature is further corrected of errors. The work is used and reproduced by other scientists, and it begins to show concordance with other fields. When this has happened, the ideas have high credibility. This is the next filter, which brings the work into the realm of textbook science. The result of textbook science is a collection of ideas that are mostly very reliable. These ideas are slowly built up from a consensus among sciences, founded on agreement between theory and experiment and concordance with other theories.

H.H. Bauer
Looking through a summary of book, I'm pretty impressed by it, and I've got it on order. My main objection is that I'm not sure a description on how science was done in 1957 can be taken at face value in 2006. There have been some huge changes since then. There have been some pretty huge changes since 1990. Kuhn I think is different because he talked in terms of principles which have been the same since the time of the Greeks. Bauer's work seems to be less timeless.

The thing that I object the most to the original text was the statement of "textbook science." One of the reasons that I'm interested in Wikibooks is that I think it is likely to fundamentally change the way science is done from the way Bauer describes it.

Roadrunner 16:58, 18 June 2006 (UTC)

 * I hope you enjoy Bauer's book.

 * I take a different view of this whole thing. Science is, despite any pluralist or democratic ideals, in a sense an authoritarian endeavor, with peer review very much central to the whole thing. Peer review is what stands between crackpottery, silliness, individual conceit, etc., of scientists, and the popular media and textbooks. I consider this very much the leading opinion.

 * I'd also like to note that I wrote the text here on the basis of a survey of reading I undertook so that I could better understand the landscape of thought on method specifically for writing this module. This text is based on writings on method that have been very carefully thought out and well received by scholars of the philosophy of science. Those writings in turn are based on research combining the writings of a variety of scientists ranging from the Revolution to the present day on how they did their thing. And each step was filtered through the personal experiences of each writer "in the trenches." I consider this a much better way of producing knowledge. Wikibooks is just another medium.

 * --Brian Brondel 17:33, 18 June 2006 (UTC)

 * Then we have a fundamental philosophical disagreement here since I think science is one of the most anti-authoritarian institutions out there. One of the reason that I enjoy science so much is that you can go to a room full of people who are older and more senior than you are and say *YOU GUYS ARE ALL WRONG*, *THE TEXTBOOKS ARE WRONG*, *EVERYTHING YOU BELIEVE IS WRONG*, and if you have your logic and facts on your side, they'll start nodding their heads.

 * In the case of astronomy, the leading journals "Astrophysical Journal" in the US, "Astronomy and Astrophysics" in Europe, have a policy of basically publishing anything that isn't obviously stupid. ApJ has a 70% acceptance rate for manuscripts and some pretty nutty stuff makes it in there (the big bang never happened!!! black holes don't exist!!!!).  One reason that peer reviewers make their feedback transparent is so that you can judge the judges.  It has happens that a submitter looks at the referee comments, concludes that the referees are idiots and then resubmits the proposal in another journal.  You will get your work in the primary literature unless it is so bad that no one will publish it.

 * Also, my opinions on peer review are colored by the fact that I've been a referee for grant proposals. One thing that happens is that you quickly find out is that there so so many good proposals coming in, and so little money available that the grant process weeds out a lot of really good projects that you hope that someone else will fund.

 * Politics also rears its head in the process. This is a *GREAT* proposal.  Too bad our program budget doesn't cover this area, and what programs do get funded and to what amounts is generally a political decision in which there is little peer review (because it is ultimately not a scientific question).

Roadrunner 18:19, 18 June 2006 (UTC)

 * Those are good points. As you say, we're more discussing theory than book content right now, so I'll keep it brief.

 * My perspective is that textbooks should have the best science, rather than the latest science. If you go to tell a roomful of people how wrong they are, they might act polite while you give your speech, but they aren't going to go home and teach your ideas to their 101 class until you've gotten to the other side of the peer review process, which probably won't be so polite. You're certainly right about peer review of journals. That's part of Bauer's point, though -- each step in the process is successively stronger. Bauer describes primary literature as "mostly not obviously wrong." Politics does come into the review process, but I think of "we'd like to but we can't" to be separate from "we shouldn't at all." There's nothing wrong with setting an agenda when not all good science can be done.

 * It's been fun having this conversation with you. I'll let you have the last word if you like, but then I should be getting back to work. I hope to see you more at Astronomy in the future. --Brian Brondel 18:58, 18 June 2006 (UTC).

added section on peer review
I created a separate section on peer review which makes reference to Bauer's knowledge filter.

I agree that peer review is still central to science, and one thing that I wanted to do is to go into some detail about the process. One thing that I like about the peer review process is that it is very transparent. In other selection systems, you get a "NO!!!! GO AWAY" but in the peer review, the response is "well, we think that there are these problems, can you check A, B, and C, change the statement on B, and resubmit."

Roadrunner 17:45, 18 June 2006 (UTC)

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


text:
User talk:CR~enwikibooks

delete
Instead of blanking pages, please mark pages that are no longer needed for speedy deletion by typing on the page. Thanks, hagindaz 00:07, 18 June 2006 (UTC)
 * OK, thanks for the tip. i will in the future.  i am done now, though.  everything under the namespace "longevity/_____" should now be deleted, if you are willing (not that is uses much hard drive space).  CR 00:09, 18 June 2006 (UTC)

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 CR. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name CR~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 23:04, 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) 04:44, 19 April 2015 (UTC)

title: User talk:CR~enwikibooks


text:
Talk:General Astronomy/Apparent Motions of the Planets

Ptolemy used this concept. He may have acquired it from earlier astronomy in Sumer (Iraq today)which was being developed as early as 2600 B.C.E. There is evidence on a copper bowl acquired by Prof. Clyde Hostetter in Riyadh in September 1976. It has non-verbal symbology about eclipses and also about the movements of the planet Venus, the manifestation of the sky-goddess Inana, who was an important part of Sumerian religion. Some of the symbols etched in the bowl indicated that Venus could be seen (without optics) as a thin crescent just before and just after inferior conjunction -- when Venus passes between the Earth and the Sun. Included in the symbology are a circle of loops suggesting that during the retrograde motion of Venus the planet came closer to the Earth. This could have suggested to Ptolemy the concept of epicycles, since he had access to the astronomical records of the Sumerians. Details and photos of the symbology on the bowl can be obtained on request from Professor Hostetter at chostett@verizon.net.

Maybe you can address what other drawbacks there were to the epicycle theory, other than inefficiencies, if there were any...


text:
Blender 3D: Noob to Pro/Simple Cloth Animation

In this tutorial, we will be making a simple skirt, and using the cloth physics system to make it fall in realistic-looking folds.

Making the Skirt Mesh

 * 1) Open Blender and delete the default cube, if you aren't looking down on the scene, press.
 * 2)  → Add → Mesh → Circle
 * 3) The circle will be created, and in the Tool Shelf on the left you should see a panel appear for adjusting its settings. Set the number of vertices to about 12.
 * 4) Switch to Edit Mode with . All the circle’s vertices should be initially selected; if not, use  to select them all.
 * 5) Press  to extrude a second copy of the vertices; press   to scale the extruded vertices in the X and Y directions. These will make up the hem of the skirt; scale it out to as large as you like. Note that this is positioning the skirt out flat horizontally, instead of hanging down as you would expect; Blender’s cloth animation system will take care of that, and this positioning gives maximum opportunity for the skirt to fall in dramatic folds.
 * 6) Now we will need to subdivide the mesh. The physics can only act on actual vertices, so the more of these we have, the more realistic the cloth effect will be. Select all vertices in the skirt, press  and select the “Subdivide” option. A panel will appear in the Tool Shelf for controlling the settings for the subdivision operation; set the number of cuts to, say, 4.
 * 7) While you’re at it, switch to OBJECT mode and look in the Tool Shelf for a pair of “Shading” buttons titled “Smooth” and “Flat” [[File:Blender263ShadingButtons.png]], and click on “Smooth”.

Creating the Vertex Group

 * 1) Now we have to specify that the waist of the skirt will stay fixed in place as it falls: deselect all vertices, and select the innermost ring of vertices. The quickest way to do this is to hold down  and click with  on one of the edges bordering the hole in the middle. With the entire ring of vertices selected, go to the Mesh Object Data context [[Image:Blender 2.78 Mesh Object Data Button.png]] in the Properties window, find the “Vertex Groups” panel, and click the + sign to create a new group. This will initially be called “Group”; perhaps give it a more meaningful name (like “Waist”), and click “Assign” to put the selected vertices into the new group.

Animating the Skirt

 * 1) Tab out of Edit Mode into Object Mode. The skirt should still be selected.
 * 2) Go to the Physics tab [[File:Blender255PhysicsContextButton.png]] in the Properties window (last icon in the row at the top). This will just show a few buttons to begin with [[File:Blender263InitialPhysicsTab.png]].
 * 3) Click the “Cloth” button; a whole lot of other settings should appear, most of which can be left at their default values (make sure the checkbox at the top of the “Cloth Collision” panel is checked). However, check the box titled “Pinning”; now you can click in the field just below it to bring up a popup menu of all the vertex groups in the mesh; this should just contain the one entry named “Waist” you created earlier, so select that.
 * 4) Now the magic happens ... rotate the view to an oblique one to give yourself a good view of the process, and hit . You should now see the skirt fall from its horizontal position to a more natural vertical one, developing some folds in the process.
 * 5) After the animation has run through at least one complete cycle, hit  to stop it.

Prior to Keeping the Folds
Before doing the next step, we need to enable one of the standard addons that come with Blender. This will let us make a copy of any stage of the physics simulation into a separate object.

Go into the User Preferences window and bring up the “Addons” tab. Look for the “Animation Corrective shape keys” addon (typing “shape k” into the search box should be enough to find it).

Enable it. Now back to the 3D view...

Keeping the Folds

 * 1) Use the left- and right- arrow keys to step through the animation one frame at a time, until you find a position for the skirt that you like.
 * 2) When the 3D view is showing a nice shape for the skirt, go to the mesh data tab in the Properties window, and look for the “Shape Keys” panel. Click with LMB on the down-arrow just below the + and - signs, and in the menu that appears, you should see the item “Create duplicate for editing” [[File:Blender263SaveAsShapeKey.png]]. Select that.
 * 3) It looks like nothing has happened, but in fact you now have a second copy of the skirt mesh, “baked” into the position corresponding to the current frame of the animation. Try using the arrow keys to move through the animation, and you will see the baked copy remain in the chosen position.
 * 4) At this point, you can delete the original animated skirt mesh (or move it to another layer for future reuse), leaving the nicely-folded copy.

Extra Practice

 * 1) You will notice at some points during the animation, the folds of cloth pass right through each other, which is of course impossible with real cloth. To prevent this, you could go to the “Cloth Collision” panel in the Physics tab, and click the “Self Collision” checkbox. Rerun the animation  to see the difference; what other effects does it have?
 * 2) Maybe the folds don’t look realistic enough. Go back to the original mesh, bring up “Subdivide” again and subdivide it by a couple more levels. Rerun the animation . It should take a bit longer for the first cycle, but do the results look better?
 * 3) This YouTube tutorial might also help: http://au.youtube.com/watch?v=mgYhZ3hWwTQ happy animating!


text:
Io Programming/Io To-Do

= Must Have List for Io 1.0 (Brainstorm) =

This is from http://www.quag.geek.nz/io/musthaves1.0.html

 * Date rewrite to take timezone offsets into account
 * Sequence renamed to String
 * Complex numbers

Documentation additions and improvements

 * Tutorials need to be written
 * Io Programming/Writing Bindings Tutorial would be helpful
 * Io Programming/Objective-C Tutorial would be helpful
 * Reference
 * Make top-level link on iolanguage.com to references.
 * Doc strings for all methods.
 * Examples for many methods.

Security / Testing

 * Security Audit
 * Security Policy
 * Safe Sandbox
 * Regression Testing

 * maybe? waterken web calculus

Bindings

 * xml
 * postgres
 * mysql

Misc Changes

 * Unicode Support in Strings
 * Binary Modules (dynamically loading bindings)
 * Regular expression callbacks.
 * printf (style) formatting would be handy to make porting software easier.
 * HTTP server (Needs explanation)
 * Readline style input
 * Arrow up / down to see a history of lines entered

= Must Have List for Io 2.0 (Brainstorm) =

 * JIT compilation
 * Rewrite portions of Io that can take advantage of JIT in Io

title: Io Programming/Io To-Do


text:
Piano/How Piano Works

Upright Piano: When a key is depressed by one's finger, the capstan button on the back of the key pushes up the wippen. Wippen raises and the jack escapes from the butt then the hammer get leaned towards the string. When the felt hammer strikes the string it causes it to vibrate. This energy is transferred through the bridge into the soundboard, which resonates. Pianos can be played softly (piano) and loudly (forte), unlike previous keyboard instruments which produced sound by plucking the string--instead of striking like pianos do today.

For further description, including an animation of the piano action working, visit:

title: Piano/How Piano Works


text: Category:Book:GCSE Science

title: Category:Book:GCSE Science


text:
GCSE Science/Rates of reaction coursework

In order to get maximum marks in this coursework it is vital that you discuss all factors which affect the rate of a reaction. These include:
 * Temperature. The higher the temperature the more energy there is within the reaction. When there is energy in the reaction more reactants hit each other and then there are more successful reactions.
 * Surface area. Smaller substances react better then large substances because the small substance has a larger surface area and if there are more reactants exposed there is more successful collision.
 * Concentration. The more molecules in a chemical the more concentrated it is. When a chemical has a greater concentration of molecules the chances of successful collisions increases and therefore speeds up the reaction.
 * Catalyst. Adding a catalyst will speed up a reaction by decreasing the energy needed to break the bonds. A catalyst is not chemically consumed by the reaction so does not have an effect on the final products.
 * Pressure. Pressure results in there being more particles of each reagent in a smaller area, resulting in more reactions.

Skill P: Planning - the theory and your experiment design!
First, you can start by describing the reaction situation you are intending to investigate. For example, with the word and symbol equation, short description about the reaction, and so on. This sets the scene. If you are confident and chosen the VARIABLE you want to investigate you should try to make a quantative prediction and maybe justify it with some theory if you can. You can continue in a broader context by introducing some background theory and descriptions of the factors or VARIABLES which may have an effect on the rate of the reaction you are studying (include briefly factors which might not apply). In your 'method' description use the correct units or descriptors. The factors to discuss might be: amount of limestone? temperature of reactants? acid concentration? volume of acid? size of limestone pieces?(relate to surface area? stirring of the reacting mixture size of reaction vessel volume of thiosulphate any added water to dilute etc.

Example of the theory is the factors will increase the molecules inside the chemical and it will eventually increase the rate of reaction.

Is there any other factor for the reaction you are studying? will any of the reactants or products be affected by change in temperature or pressure? e.g. there are several reasons why the same acid should be used if its a reactant in the investigation, e.g. (1) its the hydrogen ion, H+(aq), is the active ingredient that actually 'attacks' the metal or carbonate, and acids can ionise to different extents, (2) 1 molar or 1 mol dm-3 (1M) H2SO4 is twice as acid as 1M HCl because each H2SO4 provides 2 H+'s whereas each HCl just 1. If you have decided, for example, to investigate the effect of acid concentration on the speed of a reaction, then everything else should be kept constant for a fair test, and this should be obvious in your plan for the reasons discussed above!

If you haven't already chosen the VARIABLE, do so now, and make a prediction and justify it with some theory which you may have previously described and should refer to.

Next you should describe briefly some methods for following the reaction = measuring the speed of the reaction. If a gas is formed, there are at least two ways of collecting a gas e.g. initially empty gas syringe or a measuring cylinder/burette full of water inverted over water with appropriate tube connections and there is one other very different method available for 'following' the reaction using a balance to record the mass loss. The hydrochloric acid - sodium thiosulphate reaction depends on the time for a certain amount of sulphur precipitate to form and obscuring a marked black X on white paper.

Briefly explain how the method can be used to measure the speed - the results of the first few minutes is usually the most crucial - you can discuss (briefly) other methods, but perhaps better in evaluation as a means of further evidence.

When you have decided on the method, give a detailed description of how you might carry it out. Include details of the amounts of chemicals you might use mass, volumes, dilutions + UNITS etc. etc. Clearly indicate why the method would be expected to produce precise and reliable evidence - the results!

Complete a full risk assessment. in this you should identify the hazard and what's dangerous about it and the measures you take to reduce the risk with how effective they were. you can also include a severity rating which compares the potential severity of harm and the liklihood of harm occurring.

If you are looking at changing the reaction temperature, its not easy to accurately vary and control the temperature of the reactants without a thermostated water bath to hold the reaction flask in. Even with a thermostated water bath (normally only available to advanced level students), all the reactant solutions should be pre-warmed in the bath before mixing and start the timing and recoding of results.

If you are varying temperature, you need to heat up the reactant solutions separately and take their temperatures, mix, start stopwatch. However, they will cool a little standing out in the laboratory, so not completely satisfactory solution to the problem. In the case of the sodium thiosulphate - acid reaction, you can leave the thermometer in the flask and take the temperature at the end, then use an average for the temperature of the reaction. If temperature isn't a variable, it must be kept constant. The simplest solution here, is to make sure all the chemicals have been standing in the laboratory prior to the lesson. Then, they will all be at the same temperature, which should be recorded. If more experiments are conducted at another the time, the temperature must again be checked and recorded.

Refer to any previous laboratory experience with 'rate of reaction' experiments which may have helped you decide and design the experimental method. A clearly labelled diagram of the method with a brief outline of how you intend to carry out the experiments - this cuts down on the writing and makes the scene clear! You must give details of how long you might time the experiment as well as the time interval between experimental readings REMEMBER you can change your 'recipe' or way of doing the experiment. If you have to change anything, describe and explain the changes you have made to the procedure (some of this might count as valuable marks for the EVALUATION skill) AND DON'T FORGET AT ALL TIMES QUOTE THE CORRECT UNITS in P, O, A or E.

Skill O: Obtaining evidence
Observations, measurements, in other words the results! (Possibly some data you might have been given (secondary data))

These must be clearly recorded in neat tables showing all the units.

You can produce a summary table with the average/corrected (if necessary) gas volumes v time for all the different acid concentrations or whatever variable For the hydrochloric acid - sodium thiosulphate reaction you are recording just the reaction time for different thiosulphate or acid concentrations or temperatures, so the data gathering and subsequent processing is 'simpler'.

All experiments should be repeated where time allows checking for accuracy and consistency; this may become more necessary after you have done a preliminary analysis The 'bung effect'! - look up about dead volumes and its correction when dealing with gas volumes! Your recorded results should indicate the accuracy of the measuring equipment e.g. 0- 2 decimal places. Some of the work done here in presenting the results, e.g. working out averages etc. actually counts towards the mark for analysing (described below). Have you got enough results, do they seem ok? Starting the analysis as soon as possible will help you decide whether further, wider ranging or repeat experiments  - best decided after examining the graphs of results (see below) - difficult to decide just looking at tables of data.

Skill A: Analysing and considering the evidence
What do the results mean in terms of your prediction and theory!

The results are initially processed into graphical form ('graphing') for several reasons for both the analysis and evaluating the experimental .... they can clearly show the general trend of the effect of changing that factor or variable, highlighting experimental 'runs' that don't seem to fit the pattern of the other sets of results for the other runs, individual points that don't seem the pattern of a particular sets of results - BUT ITS UP TO YOU

Ideally you should plot the average(*) corrected gas volumes on the y axis and time on the x axis - what should the origin be? (* May depend on the consistency of your results). For the hydrochloric acid - sodium thiosulphate reaction you can plot either (i) reaction time, or (ii) 1/time versus a concentration or temperature (1/time = relative rate of reaction).

It is best, if possible, to have all the average results points plotted on the same graph for easy comparison - take care because this may involve 4 or 5 lines for 4 or 5 different acid concentrations Make sure you use a clear KEY for the different line points and a clear title for the graph AND clearly label the axis including the units or whatever .. Use smooth 'best curves' for as many of the points as possible, though some parts of the graph might be linear, watch out for the 'scatter' - the experiment is not that easy to get good results.

See Rates of Reaction Notes.

From the graph you can then describe in words what the results mean, always refer to the graph lines and gradients directly - don't make vague comments.

So what we are after is the main 'trend(s)' or 'pattern(s)' describing with reference to the graphs. Does the 'trend' of all the graph lines support you're your prediction, are all the results consistent with your prediction AND theory?

For different the acid concentrations you can do a 2nd and more advanced graphical analysis of the limestone results. This involves measuring from the graph, the speed of the reaction at the start. Explain why best data at the start? (i.e. first 3-5 mins?).

What graph could you then plot?...  where does the graph line start?, origin?, what is the 'shape' of the graph? is it a better way of showing consistency (or inconsistency!) in your results?

We are basically talking about plotting the initial rate versus e.g. acid concentration. If you are doing something like the hydrochloric acid - sodium thiosulphate reaction, your reaction time measures the formation of a fixed amount of sulphur per 'time'. So the rate is 'x amount of sulphur per time', which means the speed or rate is proportional to 1/time, then plot this 1/time against the concentration of the acid.

From this graph re-discuss your findings in a more mathematical way and relate this to the particle collision theory of reactions! It's all about chance! and explain why/why not the results support your prediction.

Skill E: Evaluating
How good are your results then? error sources? can we improve the existing method? are there other experimental methods?

Do your results seem consistent and accurate? - always refer directly to the graph or graphs in your analysis do any of the sets of results not fit in with the others? do most/all sets of results fit a pattern? are there any particular points that don't fit the pattern? (anomalies can some results be ignored in drawing your conclusion(s)? if so, which results and why? QUOTE DIRECTLY - WITH REFERENCE TO YOUR GRAPH(s)

Discuss possible sources of error which might lead to inconsistent results i.e. points or sets of results that don't fit the pattern AND how could the method be improved to minimise these sources of error ... e.g. chip size? ,temperature or pressure checks for each experiment? dead volume?, ? gas syringe operation? draughts? where these or any other factor OK? in other words how suitable was the method overall? Do think the results are reliable bearing in mind any anomalies? For the hydrochloric acid - sodium thiosulphate reaction think about the precipitate, observing it etc. What further experiments, using the same method or another method, could be done to support your prediction or conclusion? In other words give some detailed ideas on further work that would provide additional relevant evidence. e.g. in the case of the sodium thiosulphate - hydrochloric acid experiment, you can use a light gate to detect the precipitate formation. The system consists of a light beam emitter and sensor connected to computer and the reaction vessel is placed between the emitter and sensor. The light reading falls as the sulphur precipitate forms.

Keeping the temperature constant is really important for a 'fair test' if you are investigating speed of reaction/rate of reaction factors such as concentration of a soluble reactant or the particle size/surface area of a solid reactant. On the advanced gas calculations page, temperature sources of error and their correction are discussed in calculation example Q4b.3, although the calculation is above GCSE level, the ideas on sources of errors are legitimate for GCSE level. Note that if the temperature of a rates experiment was too low compared to all the other experiments, the 'double error' would occur again, but this time the measured gas volume and the calculated speed/rate of reaction would be lower than expected.


text:
Category:Book:Mythology

ko:분류:신화

title: Category:Book:Mythology


text: Category:Book:Handbook of Genetic Counseling


text:
A-level Computing 2009/AQA/Processing and Programming Techniques/Data Representation in Computers/Questions

This page contains questions to assist the reader in understanding the course material. These questions should not be taken as an indication of examination questions, and the reader should make reference to previous exams to get an idea of these.

Hexadecimal
Help is available here

 * 1) Convert the following bases to their equivalent hexadecimal values
 * 2) 8 dec
 * 3) 10 dec
 * 4) 16 dec
 * 5) 0001 bin
 * 6) 0101 bin
 * 7) 1111 bin
 * 8) 1010 1011 bin
 * 9) 128 dec
 * 10) 7485 dec
 * 11) 1010 1111 0000 1011 1110 bin
 * 12) Convert the following hexadecimal values to the given base
 * 13) E - decimal
 * 14) E3 - binary
 * 15) 73 - decimal
 * 16) BEE5 - binary
 * 17) BEEF - decimal
 * 18) The binary value of the ASCII word Bat is $$01000010\ 01100001\ 01110100_2$$. What is the hexadecimal equivalent?
 * 19) Why is hexadecimal used on computer displays instead of decimal or binary?

Negative Binary Numbers
Help is available here
 * 1) What are the denary values of the following twos complement numbers?
 * 2) 0001 1011
 * 3) 1111 1111
 * 4) 0111 1101
 * 5) 1001 1001
 * 6) 1011 1000
 * 7) Convert the following numbers into negative numbers written in binary
 * 8) 0000 0001
 * 9) 0110 0000
 * 10) 0111 1111
 * 11) 12 (denary)
 * 12) 67 (denary)
 * 13) 34 (hexadecimal)
 * 14) 7E (hexadecimal)
 * 15) Convert the following negative binary numbers into decimal
 * 16) 1111 1101
 * 17) 1111 0100
 * 18) Find the answers to the following sums in binary, show your working
 * 19) 0110 1100 - 0000 0111 = 0110 0101 => 101
 * 20) 0001 1111 - 0001 0011 = 0000 1100 => 12
 * 21) 0111 0111 - 0101 1011 = 0001 1100 => 28
 * 22) 23 (hex) - 1F (hex)     = 0000 0100 => 4
 * 23) 0001 0010 - 1111 1101 =

Binary Fractions
Help is available here
 * 1) What are the values of the following numbers where there are 4 numbers before the decimal point?
 * 2) 00111000
 * 3) 01010111
 * 4) 01101100
 * EF
 * 1) 10010011
 * 2) 11001101 (note: this number is a two's complement number)
 * 3) Using 1 byte for each number, with a fixed unsigned decimal point between bits 4 and 5, convert the following denary/decimal numbers into binary or get as close as you can
 * 4) 1.5
 * 5) 8.75
 * 6) 9.1875
 * 7) 0.5625
 * 8) 13.60
 * 9) What are the values of the following 16 bit floating point numbers, where the exponent is 6 bits
 * 10) 0111 0100 1100 1110
 * 11) 0110 0000 0011 1010
 * 12) 1011 1100 0100 0001
 * 13) 1110 0000 0011 1101
 * 14) Normalise the following 16 bit floating point numbers, where the exponent is 6 bits
 * 15) 0011 0000 0000 0001
 * 16) 0001 1100 0000 1110
 * 17) 1101 0110 0100 0010
 * 18) 1111 0111 1111 1001


text:
A-level Computing 2009/AQA/Processing and Programming Techniques/Data Representation in Computers/Answers

Hexadecimal
Help is available here

 * 1) Convert the following bases to their equivalent hexadecimal values
 * 2) $$8_{16}$$
 * 3) $$A_{16}$$
 * 4) $$10_{16}$$
 * 5) $$1_{16}$$
 * 6) $$5_{16}$$
 * 7) $$F_{16}$$
 * 8) $$AB_{16}$$
 * 9) $$1000\ 0000_2 \to 80_{16}$$
 * 10) $$0001\ 1101\ 0011\ 1101_2 \to 1D3D_{16}$$
 * 11) $$AF0BE_{16}$$
 * 12) Convert the following hexadecimal values to the given base
 * 13) $$14_{10}$$
 * 14) $$1110\ 0011_2$$
 * 15) $$0111\ 0011_2 \to 115_{10}$$
 * 16) $$1011\ 1110\ 1110\ 0101_2$$
 * 17) $$1011\ 1110\ 1110\ 1111_2 \to 48879_{10}$$
 * 18) $$426174_{16}$$
 * 19) Hexadecimal numbers are easier for humans to read, understand and remember.

Negative Binary Numbers
Help is available here
 * 1) What are the denary values of the following twos complement numbers?
 * 2) $$27$$
 * 3) $$-1$$
 * 4) $$125$$
 * 5) $$-103$$
 * 6) $$-72$$
 * 7) Convert the following numbers into negative numbers written in binary
 * 8) $$1111\ 1111$$
 * 9) $$1010\ 0000$$
 * 10) $$1000\ 0001$$
 * 11) $$0000\ 1100 \to 1111\ 0100$$
 * 12) $$0100\ 0011 \to 1011\ 1101$$
 * 13) $$0011\ 0111 \to 1100\ 1001$$
 * 14) $$0111\ 1110 \to 1000\ 0010$$
 * 15) Convert the following hexadecimal values to the given base
 * 16) $$-3$$
 * 17) $$-12$$
 * 18) Find the answers to the following sums in binary, show your working - not yet finished beyond here (YR 12 please complete!!)
 * 19) 0110 1100 - 0000 0111 = 01100101
 * 20) 0001 1111 - 0001 0011
 * 21) 0111 0111 - 0101 1011
 * 22) 23 (hex) - 1F (hex)
 * 23) 0001 0010 - 1111 1101

Binary Fractions
Help is available here
 * 1) What are the values of the following numbers where there are 4 numbers before the decimal point?
 * 2) 0011.1000
 * 3) 0101.0111
 * 4) 0110.1100
 * EF
 * 1) 1001.0011
 * 2) 1100.1101 (note: this number is a two's complement number)
 * 3) Using 1 byte for each number, with a fixed unsigned decimal point between bits 4 and 5, convert the following denary/decimal numbers into binary or get as close as you can
 * 4) 0001.1000
 * 5) 1000.1100
 * 6) 1001.0011
 * 7) 0000.1001
 * 8) 1101.1001 (as close as you can get)
 * 9) What are the values of the following 16 bit floating point numbers, where the exponent is 6 bits
 * 10) 0111 0100 1100 1110
 * 11) 0110 0000 0011 1010
 * 12) 1011 1100 0100 0001
 * 13) 1110 0000 0011 1101
 * 14) Normalise the following 16 bit floating point numbers, where the exponent is 6 bits
 * 15) 0011 0000 0000 0001
 * 16) 0001 1100 0000 1110
 * 17) 1101 0110 0100 0010
 * 18) 1111 0111 1111 1001


text: Category:Book:Interlingua

title: Category:Book:Interlingua


text:
Talk:Music Theory/Blues

This section desperately needs an editor!

_________________

"To understand Blues chord, first you need to understand the scale that is associated with the 12 bar blues, which, surprisingly, is called the blues scale." oh, the sarcasm...

Blues Music scales
Is this entry implied to remain at a basic level or can it be expanded to include more complex but important elements: e.g. the importance of microtonal characteristics or the pitches in this scale which lie between the fixed pitches of the (tempered) piano but can be more readily reproduced on stringed instruments by bending; wind and brass by alterations in embrochure?Cisum.ili.dilm

I could attempt to edit this area; please advise Cisum.ili.dilm

title: Talk:Music Theory/Blues


text:
Suomen kieli ulkomaalaisille/Sisältö/Verbityyppi 4

Note to editors. Please note also that this book takes a different view of the verb formation than many other grammar books take, although Daniel Abondolo takes a similar approach in his book "Colloquial Finnish". This is done for a very good reason. Editors should not to revise this section regarding stems and first infinitive endings without first understanding why this approach has been taken. The approach taken here reduces the number of rules that needs to be learned regarding verb conjugation and explains some phonetic effects better than some traditional grammar books. The treatment of the t in the verb endings such as osata as being part of the stem of the word and not as part of an infinitive marker is the approach taken by Lingsoft which has developed the most successful Finnish morphological analyzer FINTWOL on the market today. This is accessible on the net at FINTWOL. The theoretical foundation for FINTWOL (The Finnish Two Level morphological analyzer) is based on research done by Kimmo Koskenniemi and is the foundation of the spelling tools used by Microsoft for Finnish which were develoed by Lingsoft. For further proof see Lingsoft Stem Determiner

Type 4 Verb characteristics

 * Type 4 verb stems all end in a long vowel or a dipthong in the present tense or in the third person imperative and have past tense stems ending -si-.

 * Type 4 verbs all have dictionary forms ending in -ota -uta -ata -ätä. This is because the first infinitive needs to end in a or ä and this a or ä cannot be simply added to a stem if there are already two vowels present. Therefore the last vowel from the stem is dropped and a t is added followed by the infinitve a or ä.
 * This is the key recognisor from the first infinitive forms.

 * Type 4 verb stems have core stems in the present tense ending at least two syllables (single syllable stem vowels are all in Type 2). No Type 4 stem ends in OI- (those verbs that do are also in Type 2)

 * Type 4 verbs have many different stem forms.
 * The past tense STEM drops the a or ä that was in the present tense and substitutes si
 * The first infinitive STEM drops the a or ä that was in the present tense and substitutes t
 * The past participle STEM drops the a or ä that was in the present tense and substitutes N before adding the participle -NUT or -NYT, so in practice one always sees -NNUT or -NNYT at then end of these verbs.

 * The personal endings are just added on to the correct stem form.
 * Because in Finnish, no verb infinitive form can ever have 3 adjacent vowels, the third person singular for is the same as the basic stem form. In this sense Type verb forms follows the rule we have already seen for Type 2 verbs when forming the first infinitve (dictionary) form.

 * Type 4 verbs are sometimes subject to consonant gradation

 * The a > t transformation in the infinitive stem will reduce vowel space for any preceding hard consonants. This causes the dictionary form to be weak if the stem consonant is strong.

 * The consideration of whether the verb will experience consonant gradation is only predictable by knowing the stem of the verb. One cannot predict the stem or the consonant gradation by only knowing the dictionary form. However, the dictionary form is always predictable from the stem so it is essential to learn the basic stem of these verbs. Because of this, most bi-lingual dictionaries do not meet the needs of the student learner of Finnish.

 * So the starting point for this understanding is always the VERB STEM never the VERB'S FIRST INFINITIVE FORM. This in an important thing to understand. Thus the dictionary form of these verbs cannot predict the conjugated forms in all cases. It explains why the verb TAVATA "to meet" has the form TAPAAN "I will meet" but the verb AVATA has the form AVAAN "I will open". Similarly the verb PELATA "to play" has the form PELAAN "I will play" but PELÄTÄ "to be afraid" has the form PELKÄÄN, "I am afraid". The K in the stem PELKÄÄ is weakened by the addition of the t in the infinitive, whereas PELAAN never had a K in the stem to begin with. One has to remember that the language forms did not evolve from the first infinitive form. We will discuss this in more detail below.

 * The a > s transformation that happens when forming the simple past tense before the plural -i- is added does NOT cause the stem to weaken. (Contrast this with the a > t transformation which DOES cause the stem to weaken. This is an exception to the general rule that consonants that close a syllable can weaken a preceding hard grade consonant.

Forming the First Infinitive (Dictionary form)
You will see in the table below that the conjugation for person is identical to that we saw in Type 2 verbs which also have a long stem ending. Type 4 verbs however differ because they have an a or ä as the last vowel in the stem. This causes some changes in the way the first infinitive or dictionary form is formed.

We begin by re-iterating the fact that all Finnish verbs have a first infinitive (i.e. dictionary listed) form ending with the letter -a or -ä.

Consider the verb stem holhoa- to take care of

Making the first infinitive or dictionary forms from this verb stem is tricky because to add another -a as the infinitve marker would mean creating a verb form with 3 vowels (theoretically, holhoaa) but that is not allowed in Finnish. What happens therefore is that the final -a of the stem holoa- is transformed into -t (this becoming holot-) and then the infinitve marker a is added. This gives us the dictionary form holota (holhot-a) to take care of.

Lets tabulate another, more common verb, osata to have the skill or ability to do something

Note that the word can in English can mean both have the power or freedom to do something (which in Finnish has the verb stem voi-) as well as the ability or skill to do something (which in Finnish has the verb stem osaa-). So one has to be careful to choose the right Finnish verb when expressing the word can.

The dictionary form is sometimes weak grade
If one of the consonants or consonant clusters affected by consonant gradation appears immediately before the long -aa in the verb stem, then the long -aa causes it to be heard as Strong Grade when conjugated for person. This is according to the normal rules. However, the transforming t which replaces the final a in the stem when forming the first infintive or dictionary form is sufficient to weaken any preceding consonants in the stem, also according to the standard rules of consonant gradation. '''IT IS VERY IMPORTANT THAT YOU UNDERSTAND THIS. '''

For instance the words me hankaamme means we rub, but the dictionary form of the verb is hangata. The present tense stem is hankaa- but the dictionary stem is hangat-, the t in the stem weakens the nk to ng according to standard rules of consonant gradation.

hangata - to rub

'''These consonant changes make it very hard for the novice Finnish student to trace for example the meaning of the Finnish verb in a dictionary unless he or she understands how the dictionary form is constructed. '''

The stem form and consonant gradation is not predictable from the dictionary form
This is best illustrated by comparing two verbs in Finnish, the verb meaning "to meet" and the verb meaning "to spell out, letter by letter".

Lets start with the verb meaning "to meet".

I meet or I will meet in Finnish is minä tapaan. Similarly

He meets or He will meet in Finnish is hän tapaa

So we can say that the verb "to meet" has a present tense stem form tapaa- followed by the relevant personal endings according to normal convention.

Note that the p in the stem is not strong pp but p, yet this p is followed by a long vowel space. This long vowel space normally preceeds strong form consonants, so in fact, this p could, in theory become weaker still if closed out by a consonant at the end of the syllable. We known that a single p can be weakened to v.

The dictionary form or first infinitive marker is a or ä according to front/back vowel conventions. But this is a problem for stem tapaa- .... how can we add an extra a to tapaa- because that would make tapaaa, and by convention no Finnish word contains 3 adjacent vowels. The solution adopted by Finnish is to contract the long vowel to a short vowel by dropping the final a of the stem, adding t as new separator, then adding the a marking the infinitive. That leaves us with tapata..... but because we have reduced the vowel space, the P is indeed weakened according to normal consonant gradation rules to V so we get the correct form for this verb which is TAVATA.

Let's now consider the verb meaning to spell out letter by letter, or simply to spell. This verb has a present tense stem tavaa- probably ia related to the noun tavu meaning syllable

I spell or I will spell in Finnish is minä tavaan. Similarly

He spells or He will spell in Finnish is hän tavaa according to standard rules.

Making the infinitive of this verb leads us to the same problem we had with tapaa-, so the same solution is adopted. We effectively drop the last a from the stem, and separate the stem and the infinitive marker a with a letter to to make TAVATA.

So, rather amazingly, we have two identical verbs with a dictionary form TAVATA with different stem forms depending on the meaning, whether it is TO MEET or to TO SPELL OUT LETTER BY LETTER. In practice, this is no different to English homonym verbs such as TO RAIN and TO REIGN ... context will always help us distinguish which word is intended.

Use the Verbix verb conjugator to enter the verb tavata to compare all the possible forms of these two verbs.

But the important thing to note is that one cannot predict the stem just knowing the verb from the dictionary.

Thus knowing that the verb tavata to meet can become tapaan I will meet does not mean that avata to open will become apaan because it does not. It does in fact become avaan I will open.

Learning tip: Do not learn these verbs from a dictionary, but do learn them as you meet them in real life. Foucus on learning the stem form(s) and the translated meanings and rather less on learning the dictionary forms. The dictionary forms will come to you with practice. Try also to understand the root meaning in the stem forms as with tavaa- and its related words such as tavatus.

TAPAN versus TAPAAN. It is worth contrasting the verb tavata to meet with another verb altogether which is tappaa to kill or slaughter. If you say tapan lapseni instead of tapaan lapseni you could get some rather odd looks from your Finnish friends. Make sure the long vowel is present when you want to meet people instead of slaughter them!!

Simple Past Tense (Perfect Tense) Formation
The past tense marker -i- in Type 4 verbs is added to the verb stem, but the final but cannot be added to the stem without modification because otherwise the verb would contain 3 adjacent vowels and we know that this is not allowed. Finnish gets around this problem by modifying the final a of the stem into s.

Note: The past tense a to s transformation DOES NOT close the vowel space so the verb stem remains strong. This is in direct contrast to the a to t transformation in the dictionary form which DOES close the vowel space making the infinitive stem WEAK.

For instance, tavata - to meet  has a basic strong grade stem tapaa- in the present tense, a weak grade stem tavat- in the dictionary form (the a > t transformation weakening the p to v according to standard rules) but strong grade stem tapas- in the simple past (imperfect) tense (the a > s transformation is NOT able to weaken the p consonant).

Past Participle
Just as there is an a > t transformation in the formation of the infinitive stem, and an a > s transformation in the past tense stem, the past participle stem has a similar a > n transformation.

Because the past participle has the ending -nut or -nyt, the a > n transformation in the stem causes Type 4 verbs to have participle forms ending -nnyt or -nnut. Because Finnish cannot tolerate have two strong consonant clusters separated by a vowel or a dipthong, if the stem contains a strong final consonant, the stem's final consonant is weakened.

Lets see how all these transformations we have see so far work

Minä hyppään I'll jump The first person form, long vowel stem with strong grade hyppää-.

Hypätä to jump The dictionary form with ä > t stem transformation. The t moves the stem hypät- to weak grade.

Me hyppäsimme We jumped The past tense with ä > s transformation. The s is followed by past tense -i-. The s does not, however, move the stem hyppäs- to weak grade

He ovat hypänneet They have jumped The participle stem is now hypän- following ä > n transformation. The stem contains weak p because the following consonant is a stong nn.
 * Note nn is usually a weak form of the cluster nt, but this -nn- is not derived from -nt-, but is stronger than single n and therefore weakens the preceding consonant pp to p.

Conditional formation
The conditional marker is -ISI- and is added between the stem and the personal ending. But Type 4 verbs have rather a lot of stem forms as we have seen. Which is the right stem form to use?

The simple answer is that it attaches to the present tense stem, but as the present tense stem ends in two vowels and the conditional marker begins with another vowel, we have a problem, because we know that no verb form in Finnish can have 3 consecutive vowels.

What happens is that the last vowel of the present tense stem is dropped.

Han hyppää he jumps

Hän hyppäisi he could jump

Minä hyppäisin I could jump

The standard vowel space rules for consonant gradation apply and the stem remains strong grade.

Summary of Stem Modifications
As we have seen, Type 4 verbs can have several stem forms.

For example HANGATA has the following stem forms

HANGAT- for the dictionary form, the passive, and certain imperative forms

HANKAA- for the present tense

HANKAS- for the past tense

HANGAN- for the past participle

HANKAI- for the conditional forms (this is arguably HANKA-, but HANKAI- is how Lingsoft morphology shows this form)

It is a good idea when learning verbs to practice forming these various stems forms at the same time. Your attempts can be checked from the Lingsoft web site, or from on-line verb conjucators such as that at verbix, or logos, or in certain printed dictionaries (e.g. the Nykysopmen Keskeinen Sanasto) that show all these forms. With some practice, and trial and error the formation of the right stems will become easier.

Similarity to Type 2 verbs
Type 4 verbs are similar to Type 2 verbs in that both types of verbs have stems ending in long vowels or dipthongs and conjugate for person in exactly the same way.

The main difference is that Type 2 verbs do not have the consonant gradation effect and Type 4 verbs form the first infinitive form, the past tense and past participle forms very differently, and of course have the infinitive separator d instead of t.

You can learn more about Type 2 verbs in the appropriate section of this book.


text:
Blender 3D: Noob to Pro/Basic Animation/Bounce

How to make a ball bounce convincingly!
'''This tutorial assumes basic Blender awareness and some knowledge of using Blender Lattices as well as keyframes basics regarding the Blender Panels. Knowledge of IPO curves will prove useful later as we progress to more advanced techniques.'''

How hard can it be to move a ball?
It would be easy to just put a sphere on the screen and animate it to move up and down but in all honesty, it would not look like a bouncing ball. It would not be convincing in any way.

To be believable, the ball must use some of the most fundamental principles of good animation. In particular, the ball must squash and stretch and change speed as it falls, hits the floor, bounces and rises ready to fall again. With a little effort we can make that boring sphere look alive!

Why use a lattice?
It is possible to make a simple bouncing ball animation without using a Lattice object but with the Lattice we can do more than just bounce the ball. For example, once we have a ball that bounces how we'd like it, we can later add rotation to the ball so it spins through the air and bounces then, as the bounces decrease, the ball can roll to a halt. Doing this without lattice would be a far more complex exercise as a rotating squashed and stretched sphere would look like it was wobbling in space (like having the flat part of a flat tire spin around the tire instead of staying on the bottom, even while the wheel is turning).

Let's begin then
To begin, add a UVSphere (SPACE add>mesh>UVShere) in Top View (NUM7). It is important to add the objects in top view to keep their Z-Axis aligned upwards. Set Smooth and Sub-surf on the sphere if desired. Tab back into Object Mode then immediately add a Lattice(SPACE add>Lattice). Resize (SKEY) it so it closely surrounds the sphere. Make the edges of the lattice align with the circumference of the sphere as this will make animation easier.

(By default the Lattice Object Name is "Lattice". It is good to give all your objects unique and sensible names, especially if you are planning a complex scene. So you might call the Sphere "Red_Ball" and the Lattice "Red_Ball_Latt" or something similar for easy reference and recognition later.) (Noob Tip: I have formed the habit of naming everything in ALL CAPS.  As the scene gets more complicated I can easily keep track of what I have named and what needs naming.)

Top view of UV-Sphere inside selected Lattice

Make the lattice deform the sphere
Prior to Blender 2.4, objects were parented to Lattices with a Lattice Deform option. In version 2.4+ you can select the object (the sphere) and apply a Lattice Modifier to it (Ob: Lattice). However, if you use this new method then the ball will not move where the Lattice moves and will not squash when the Lattice squashes and we want it to do both of these things.

Luckily you can still use the good old Parent option then use the Modifier palette to make the Lattice Deform "Real". So select the sphere and THEN SHIFT SELECT the Lattice then CTRL-P to make parent and choose the "Lattice Deform" option. If you now select just the sphere, press F9 and look in the Modifiers palette, you'll see a listing for "Lattice parent deform" with a button for "Make Real". You can either ignore this button or press it. It really won't matter for now. If we wanted to do some weird things to our ball, like kicking it or deforming it in other complicated ways, then we would have to use the "real" Lattice modifier option.

So, this may not be the purist approach to using a Lattice but it is a convenient way to achieve the results we're after. Basically, it works and is reasonably intuitive.

Lattice Modifier screen using parenting option.

If you press "Make Real" you enable the full Lattice Modifier

(None of this seems to be necessary in later versions. The full Lattice screen comes up as soon as you Parent it.)

You can easily check if the Lattice is working the way we want it to by selecting the Lattice and resizing, moving or rotating it. The ball should do everything the Lattice does. I don't wish this to be a full lesson in Lattices so if you don't understand any of the above, or you're certain your Lattice is not working as it should, then please learn a bit about lattices before proceeding.

Time to animate!
For our basic animation, we'll use just 23 frames starting with the ball high then falling, squashing, bouncing and ending up back where it started. When this is played back in the 3D window, it will loop and we'll see the ball bounce forever in one place.

This part is easier done in "SCR:1 - Animation" Viewport configuration. It is also useful to have multiple orthographic views open in the viewport by right clicking on the resize viewport arrow and choosing "split area" then making a top view, side, etc...

Go to Front View (Num1) Press F10 and set your start (Sta) frame to Frame 1 and your end frame to Frame 23. Then make sure you're on Frame 1 (Shift+Left Arrow) to start animating. Note that we are animating the Lattice, not the ball. Everything we do to the lattice will directly affect the ball too.

Note: all the modifications to the lattice must be done in 'Object' mode. If not, they will affect all the frames.

Select the Lattice (NOT the ball) then do the following on the corresponding frames: (Noob note- This may seem obvious, but move the lattice BEFORE you insert the keyframe.)
 * FRAME 1: Press IKEY and set a key for LocRotScale - the ball's start position (high).
 * FRAME 11: Move the Lattice to ground level and key LocRotScale again (keep the fall distance small for now).
 * FRAME 13: Leave Lattice in same position as frame 11 and key LocRotScale again.
 * FRAME 23: Move Lattice back to start position (use Num (N) Panel if you need to)and key LocRotScale again.

These four frames give a basic up and down animation with a pause at the bottom. We can add squash on Frame 12 to finish off.

 * FRAME 12: Place the cursor at the base of the Lattice then set the Rotation/Scaling Pivot to "3D Cursor" [[Image:BouncepivotSS.jpg]] Scale the Lattice down along the Z-Axis SKEY-ZKEY and see the ball squash. IKey LocRotScale again.

When you have set all five keys, you can cycle through the frames and you should see the following result on the Key frames we just set. Screenshots of the 3D window, front view, on each of our five key frames.

If you press Alt-A now in the 3D window, you should see the ball bounce. Even though the squash happens on just one frame, it still reads properly in our minds and is a vast improvement over an animation with no squash at all. (Press RMB or ESC to stop the animation playback).

If you have a camera and lighting suitably set up you could render the animation out and use Blender's "PLAY" button to loop the rendered animation. See the bottom of the page for an OpenGL render made from the steps above. Add material to the ball and a ground plane for a more interesting result.

Looking at the IPO Curves
If you want the ball to bounce three times then you could repeat the above instructions three times over - if you have the patience - but Blender has a better, easier way.

Select the Lattice then open up an IPO (InterPOlation) window and zoom into the group of keys. If you select LocZ and SizeZ from the channel list on the right, you should see something like this (I've added labels to the screenshot):

''Note the IPO Type here is "Object". Purists may be disturbed or perplexed by this but if you remember, we're not really using our Lattice in the purist, Lattice Modifier form. Don't worry about it though. It works.''

IPO curve for Lattice, showing LocZ and SizeZ channels.

This shows the relative position on the Z-Axis and size in the Z-Axis of the Lattice. You can see that the Size remains constant until frame 11, then reduces, then goes back and remains constant until frame 23. Similarly, the LocZ curve shows how the ball starts high, falls then stops before rising again. The rounded bottom of the LocZ curve occurs because the IPO curve maps the centre point of the Lattice and when we squash it, the centre point lowers slightly.

Of special interest is that by default, Blender uses Bézier curves for IPOs and this gives us rounded tops on the curve. This means the ball starts moving slowly downward then moves faster until the reaches the bottom. Also, as it nears the top, it slows down again. This is good because this is exactly what happens in reality when a ball rises and falls (It could be better - but it's a good start).

While in the IPO window, select both curves then press KKEY and you'll see each key frame indicated by a vertical line. (Note: You can also press View->Show Keys if you can't remember this shortcut - this has helped me in the past.)

IPO window set to show key frames

Press AKEY to select all key frames then duplicate (Shift-D) them. The curves will seem to deform but when you drag the frames to the right, they will sort themselves out. Position them so the "first" frame is at Frame 24 and the new end frame is now Frame 46. Reset the End Frame in the Scene (F10) window then watch the animation again. It's not bad. You can repeat this process for more bounces. (To have it bounce forever throughout a long animation, ignore the above procedure and just set the "Extend Mode" to "Cyclic" in the Curve menu. You'll have to adjust the curve a little on the first and last frame but you only do it once and Blender repeats the change for all other cycles.)

Noob Note: Instead of IPO window, go to Graph Editor. I was not able to find any way to get yellow lines at each Keyframe, as above, but using put Bezier handles at each keyframe. I need to experiment to find out how to use them. worked as above.

It's not bad for a start but there's a lot more to do to this ball before applying for that animation job.

Note: In newer versions of Blender, you can go to Graph Editor, Select all graphs with AKEY, and select Channel-Extrapolation Mode-Make Cyclic. This will extrapolate the existing graphs to cover the total frames.

Saving The Animation
How do you tell Blender where to save the animated frames? The answer is in the “Output” mini-window that you see in the Render settings (F10). Near the top of this are two editable text fields, the first of which is initially set on my Linux system to “/tmp/” and the second to “//backbuf”. The first one is the output pathname or directory prefix used to save the generated frames as JPEG files when you press the “ANIM” button. If it has no “#” characters in it, then it is used as a directory prefix; thus, the default will be to save the animation frames as /tmp/0001.jpg, /tmp/0002.jpg etc. Alternative, if you put in a filename spec with “#” characters in it, the hashes will be replaced with the frame number. Thus, if I set the field to “/home/ldo/Documents/BlenderTuts/ball####.jpeg”, then the frames will be saved to that /home/ldo/Documents/BlenderTuts directory and be named ball0001.jpeg, ball0002.jpeg etc.

So what next?
In real life and in a typical cartoon, balls don't just bounce forever in one spot. They move along and slowly lose their bounce before rolling to a halt. And they have more character than our bouncing ball.

Things to consider next:
 * Perfecting the squash - maintaining volume
 * Adding stretch
 * Look at acceleration and deceleration
 * Rotate the ball as it bounces
 * Reduce the bounce height over time
 * Move the ball around as it bounces

See this ANIMATION LINK (580kb, AVI-DivX) for an idea of how you can achieve interesting results with just a little more effort. but its k? k

Links
Principles of bouncing ball animation: http://www.idleworm.com/how/anm/01b/bball.shtml

Blender 2.49B bouncing ball animation: http://www.youtube.com/watch?v=BEY_6dFdUJY

Blender 2.49B vector blur animation, to add realism to your animations: http://www.youtube.com/watch?v=qY4WcNgEXv8


text:
Talk:IB/Group 4/Computer Science

Hi, we may be able to share a lot of resources with the A-level Computing, feel free to take a look Pluke 12:15, 18 June 2006 (UTC)
 * Hello again. You seem to be putting some great work in here.  Take a look at A-level Computing and you may be able to find some info you can adapt or improve on. Keep at it. Pluke 12:19, 19 November 2006 (UTC)

How to number the Section Headings

There is no need to explicitly number the sections in the text. Let the wiki auto-number the sections. Otherwise, section numbers will appear twice in the Table of Contents. For example, when editing the text, do not enter ==2.5 section-name==. Instead, just enter ==section-name==.

By default it seems that section numbers are not displayed in the text. To display the section numbers in the text, log in and edit your preferences to enable "Auto-number headings" (Preferences > Misc)

MarkHayes (talk) 03:57, 25 February 2008 (UTC)

2 comments on 3.6.2

Validation method checking is described as 'check digits, range checks, picture/format checks, and data type checks', however there is no description of each of these checks individually, which may be desirable to add at a later stage. (e.g. Range checks are used in numeric data so that the value entered falls into a certain range of values, data checks take place when data values are compared to an expected data type, etc.) The explanation of weighted and unweighted check digits can also be included.

This section may be referenced with Chapter 1.1.7 Testing which include what type of data are tested for (normal, abnormal, and extreme, and the explanation of these).

Does everyone in the world understand what "IB" stands for?

Naming conventions for books
This is not a book, it's a subpage. Everything in the project infrastructure, from the simplest to the most complex, assumes that the name of a book is the part of the page name before the first slash. --Pi zero (discuss • contribs) 18:03, 3 November 2016 (UTC)

title: Talk:IB/Group 4/Computer Science


text:
Template:Orthopaedic Surgery/TOC

 * This is the main Table of Contents Navigation template for the wikibook Orthopaedic Surgery.
 * Add the template by adding the following to the top of the page:
 * Replace the Chapter Name as appropriate but leave it blank for the first page of every chapter.

title: Template:Orthopaedic Surgery/TOC


text:
Embedded Systems/ARM Instructions

We go into more detail on how to use ARM instructions in ../ARM Microprocessors/.

title: Embedded Systems/ARM Instructions


text:
A-level Computing 2009/Print version

The final AQA A-Level Computing Text Book will consist of 4 books:

AS

 * Unit 1 - print version (preview)
 * Unit 2 - (preview)

A2

 * Unit 3
 * Unit 4

title: A-level Computing 2009/Print version


text:
Category:Book:Modern Greek

tr:Kategori:Çağdaş Yunanca

title: Category:Book:Modern Greek


text:
Mac OS X Tiger/System Preferences/CDs & DVDs

This simple pane lets you decide what to have your Mac do when you insert a certain kind of disc. You can have your Mac ask you what to do every time, run an application, run an AppleScript, or ignore the disc entirely.


text: Category:Book:Muggles' Guide to Harry Potter