Welcome!
Hello, Petergans, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:
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Nimur
09:11, 19 March 2007 (UTC)
Hi Peter. It looks like you put two really good articles on your user page. Do you want me to split them up into subpages for you? That way you can have both drafts in your userspace to edit as you please. -- HappyCamper 18:36, 14 April 2007 (UTC)
Hi Peter - Somebody gave me a link to a Word to MediaWiki converter: [3]. I've never experimented with it before, but it might work. As for item two, I don't think there is an editorial standard on Wikipedia yet. Go with what's easiest to use for now. As for the templates, feel free to edit them. There is this policy which governs this. Personally, I'm aiming to be even more ambitious and make a navigational template similar to Template:Physics-footer. It would be really great to organize all the chemistry articles in this way. -- HappyCamper 19:10, 26 April 2007 (UTC)
Hi Peter - I thought it might be better to make a new section here since we'll be talking mostly about your draft. I'm glad the Word macro worked out well. I don't think it's possible to render the math equations with smaller font. Generally, if the equation is "sufficiently complicated", it will be rendered with the larger TeX font. If you click on "my preferences" in the top right hand corner of your screen, there might be a better local setting for your computer. The full path to your draft is User talk:Petergans/draft, so [[User talk:Petergans/draft]] will refer to it. The [[/draft]] notation is just a shortcut way of referring to subpages. In other words, if you were editing on say, Talk:Equilibrium constant, the [[/draft]] page would actually refer to [[Talk:Equilibrium constant/draft]]. -- HappyCamper 04:02, 29 April 2007 (UTC)
Thanks for your message. I have to keep this response brief for now, but I'll come back with more when I get the chance to.
I've added some comments to your help desk question. - Mgm| (talk) 22:31, 8 May 2007 (UTC)
It's probably easiest to do this by example. Click on Agamenon (which is a misspelling). It will redirect you to the correct article. In the upper left hand corner, you should see a tiny blue link that says "(Redirected from Agamenon)". It should be right under the article title. If you click on this page, you will get to go back to the original location of the redirect - and naturally, you'll be able to edit this page. -- HappyCamper 16:29, 9 May 2007 (UTC)
If you're talking about the interwiki links on the bottom of the article, they work differently in the user space than they do in the mainspace. They're formated correctly, and when the article is moved to mainspace they will work as expected. I'll remove the helpme, but please put it back if this does not answer your question. Cheers, ➪ HiDrNick! 13:30, 10 May 2007 (UTC)
I hope I've helped a bit. One thing about the draft. 2 citations in an article this size is too little. See if you can use any of the general reading entries as a reference and make sure you provide a citation to back up the definition you give in the very first line. Also "as the reaction is driven to the left" may need a more overt wording explaining exactly which particles react to become what to restore the balance. - Mgm| (talk) 10:05, 11 May 2007 (UTC)
So you removed my square brackets. I have to say that I disagree with you, and just because thy're not in the hydronium article doesn't make it right. Maybe I'll sneak them back in when you're not looking.
As for [HF2- being a three centre, two electron bond... Thinking about it, I think it's actually a three centre, four-electron bond, as the non-bonding three centre MO is filled as well as the bonding one. I've not come across such a thing before though; I'll look it up tomorrow. If you think about it as HF hydrogen bonded to F-, it's obvious where the four electrons come from. Chris 17:59, 14 May 2007 (UTC)
Thanks for your message. I saw that you were at Leeds and figured you might know them. I remember the late great Ron Snaith telling me once that one of them (I forget which) was his father in law, and that I had to buy the book because he needed the money :)
I changed the bonding in [HF2- to 3c-4e; the references there are very clear that this is the correct desciption.
Incidentally, I think this : ⇌ looks better than this:
Cheers, Chris 20:21, 14 May 2007 (UTC)
I left a response at Wikipedia:Requests for feedback to your question on Reversable Chemical Processes. Please read it over and let me know if it makes sense. -- Jayron32| talk| contribs 05:18, 15 May 2007 (UTC)
It's always a joy to see other inorganic chemists out there; so many people tend to go towards organic chemistry as i have in the past, but find myself drawn more to inorganic and physical :-). Thanks for coming to wikipedia, hope you decide to edit lots here! ♥♥ ΜÏΠЄSΓRΘΠ€ ♥♥ slurp me! 20:16, 23 May 2007 (UTC)
I'm sorry for the lack of response on my part, but I have been busy with other things. You could ask the nice guy who posted above me to help out, but if that doesn't work, I suggest talking to the Wikipedia:Mediation Cabal. If the person in question keeps reverting without any sort of discussion, you're doing nothing wrong in reverting him as long as you try to initiate discussion. - Mgm| (talk) 08:25, 29 May 2007 (UTC)
You are right, it is not correct to say time-derivative. I was fully aware that it was a mistake, but I thought it would simplify the writing. In hindsight, it was a mistake. I've corrected it. Loom91 20:54, 4 June 2007 (UTC)
After some delay due to travel I have replied to your questions in my talk page. -- Itub 07:14, 5 June 2007 (UTC)
If you want attention from an administrator, please ask for attention from another administrator. At the moment I am too busy to help you out. WP:AN or WP:ANI should be helpful. - Mgm| (talk) 17:24, 20 June 2007 (UTC)
Thank you for your contributions to the Activity coefficient article; it is much the better for it. I think, however, I have espied an error.
You wrote, "As concentrations tends to zero, activity coefficients tend to one, so in very dilute solution, activity is equal to concentration." (I have taken the liberty of adding two commas).
Shouldn't it instead read "As concentrations tend to one..."? Since according to the equation,
if were zero, would be -∞. One the other hand, if referred to the mole ratio of the solvent instead of a solute, would correspond to a dilute solution. This would give the desired result
Or am I misunderstanding something?
Upon further consideration, I realize that it's not whether a particular substance is a solute or a solvent that counts--the distinction fades to nothing when both substances are infinitely miscible--but whether or not they are pure. I'm going to go ahead and change the article to reflect this. Please feel free to revert me if you think I'm making a mistake.
I feel that my last statement requires a clarification. There is at least one property that does depend on whether a substance is a "solute" or a "solvent": the activity coefficient of the substance that is nearly pure approaches one; the activity coefficient of the substance that is greatly diluted does not. Sorry to clutter up your talk page with my ramblings :)
Hi, I just wanted to thank you for suggesting reorgaizing the least squares related articles and in doing it in such a smart way (on a talk page, and giving people lots of time to respond) I disagree with Oleg's comment on your push for consistent notation, I think it's great that you are thinking of the project as a series of articles, not just a few here and there. Pdbailey ( talk) 16:49, 24 January 2008 (UTC)
Hello Petergans! A number of mathematics editors have been discussing the Least squares article. You are welcome to add your own comments there. EdJohnston ( talk) 18:29, 31 January 2008 (UTC)
I moved User:Petergans/b/sandbox to Non-linear least squares. Thank you for the fine work. However, I would disagree with merging Gauss-Newton algorithm to it, and other people seem to echo my sentiments that such a merge would make things harder to understand.
I also further commented at Wikipedia talk:WikiProject Mathematics. My suggestion there is that we attempt to make linear least squares easier to understand before attempting further rewrites.
You can reply here if you have comments. Cheers, Oleg Alexandrov ( talk) 04:16, 1 February 2008 (UTC)
I see that you are still working on this article in your sandbox. I think if you want to contribute to that article you should edit the Linear least squares article directly rather than keeping a parallel version in your sandbox, and we should discuss any differences. Wonder what you think. You can reply here. Thanks. Oleg Alexandrov ( talk) 04:41, 8 February 2008 (UTC)
The reason for doing this is is that I have been trying to achieve consistency between least squares, linear least squares, non-linear least squares, Gauss-Newton algorithm and eventually some of the related articles. This was the purpose outlined in my major proposal. I know you don't approve of "grand projects", but I see this rather as a tidying up operation. If I had worked on the article directly some of the changes would not have made sense.
Regarding linear least squares, I have said that some of your recent edits were unacceptable. This is very strong criticism and I stick by it. To me your latest definitions section is very hard to understand, even without norms. My new version uses simple algebra which should be much more accessible to non-mathematicians.
As it happens I am going live today with all four revised articles, with a note of explanation on Talk:Least squares. I am suggesting that general comments be made there, but comments specific to each article be made on the respective talk pages, where I will also place notes.
Incidentally this is the dictionary definition of objectionable: unpleasant, offensive or repugnant. I know you meant to imply that it was something to which you objected, and I let it pass as English is not your mother tongue, but I thought you should know.
Petergans ( talk) 09:09, 8 February 2008 (UTC)
I wrote a comment on the rewrite of that article at Talk:Gauss-Newton algorithm#Response to rewrite. Oleg Alexandrov ( talk) 03:25, 9 February 2008 (UTC)
The section about the oxidation state of iron in oxyhaemoglobin is wrong. It is now known that it is low-spin Fe(II). See Greenwood and Earshaw, Chemistry of the Elements 2nd edition, pp 1099-1100. The key point is that in deoxy-Hb the high-spin Fe(II) is too large to enter the plane of the porphirin ring (Figure 25.7) but when oxygen binds the low-spin Fe(II) enters the plane as it is small enough. The paramagnetism of O2 is destroyed because the Fe-O2 angle is 120o, so the pi-star orbitals are no longer doubly degenerate.
I'm not a biochemist, so I hesitate to edit the article myself. Petergans 09:56, 11 May 2007 (UTC)
Sorry but I'd prefer not to enable email – i wouldn't mind receiving an email from you, but I don't want anyone on wikipedia to be able to email me. I'd rather conduct conversations on talk pages (whether article or user - decided to move this to your User talk page as it seems to be a 2-party conversation at the moment). I think something's wrong with your regression results. It could just be the units. But in results of the last model in the example (without the linear term in height) the coefficient of x2 is clearly inconsistent with the graph. I've just rerun the model in my favourite statistical package ( Stata) and got this:
. regress weight height2 Source | SS df MS Number of obs = 15 -----------+------------------------------ F( 1, 13) = 2208.52 Model | 689.315143 1 689.315143 Prob > F = 0.0000 Residual | 4.05750798 13 .312115998 R-squared = 0.9941 -----------+------------------------------ Adj R-squared = 0.9937 Total | 693.372651 14 49.5266179 Root MSE = .55867 ---------------------------------------------------------------------------- weight | Coef. Std. Err. t P>|t| [95% Conf. Interval] -----------+---------------------------------------------------------------- height2 | 18.60872 .3959729 46.99 0.000 17.75327 19.46416 _cons | 11.14818 1.093288 10.20 0.000 8.786274 13.51009 ----------------------------------------------------------------------------
This appears more consistent with the graph. Qwfp ( talk) 20:24, 2 March 2008 (UTC)
I agree, it's not an ideal illustration. The motivation for plotting with ht2 on the x-axis was to illustrate the fact that w/ht2 is not constant, but the variable choice is potentially confusing. The model y = a + b ht+ c ht2 is also adequate, as was the original cubic. Can you suggest a better data set? We need a system for which there is a good reason to expect that a quadratic will fit the data. Petergans ( talk) 17:50, 3 March 2008 (UTC)
Couldn't find anything useful there, so I've finally settled a quadratic model . That's me done with this article. From now on it's up to others to improve it. Many thanks for your correspondence, it has been really useful. Petergans ( talk) 15:08, 4 March 2008 (UTC) /* Linear regression Example: heights and weights */ ::I had a quick look and that's certainly clearer. I appreciate all the work you've put into this article. Regards, Qwfp ( talk) 17:21, 4 March 2008 (UTC)
Check out what I've put in the talk page as descriptions of the mean and predicted response. I'm sure the language can be refined somewhat, but it explains the concepts and gives the start and end of the derivation :) Velocidex ( talk) 04:07, 11 March 2008 (UTC)
I wonder if you have any comments regarding my comment at Talk:Gauss-Newton algorithm. I have my own proposal for a rewrite, but I wonder what you will say first. Thanks. Oleg Alexandrov ( talk) 02:28, 12 March 2008 (UTC)
Dear Peter, I recently proposed starting a "probability and statistics" sub-project (aka task force or work group) of WikiProject Maths and was wondering if you'd be interested in participating. If so, please add your name and any comments at WP:WikiProject Council/Proposals#Probability and statistics. Regards, Qwfp ( talk) 21:57, 12 March 2008 (UTC)
Peter, I wonder if you could comment on the recent discussion on Gauss-Newton. What you've been claiming about the data-fitting application having better convergence properties is wrong, the algorithm can fail even for data fitting, and the second derivative of data-fitting residuals may not be zero even at the minimum.
The plan is to merge the two sections on convergence, as the properties of the algorithm are the same in data fitting as in the general case. Please state your objections there. Oleg Alexandrov ( talk) 15:23, 17 March 2008 (UTC)
Hi Peter, we seem to have made large edits simultaneously on ADC. I'm currently in the process of resolving the edit conflict by integrating my changes into your version, please hold until my next edit save. It shouldn't take more than 10 or 15 minutes. EagleFalconn ( talk) 14:08, 23 July 2008 (UTC)
Follow up question to this: In the new lead you use pK frequently when discussing applications. Should this remain pK or for the sake of consistancy within the article, is it correct to change those to pKa? EagleFalconn ( talk) 14:14, 23 July 2008 (UTC)
Howdy, I'm looking at listing Acid Dissociation Constant on WP:FAC. Any reason for me to wait? EagleFalconn ( talk) 16:54, 4 August 2008 (UTC)
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I mean this in the best possible way, but out of curiosity do you just have a library of relatively old chemistry books sitting around in your office or at home? Every time you reference a book it seems to come from the pre-1980s, and I'm curious where you're finding them. EagleFalconn ( talk) 13:51, 8 August 2008 (UTC)
I've got no problem with old books -- I'm frequently dissatisfied with a lot of my textbooks in school because they focus on pictures instead of rigor. Prime example would be my physical chemistry book...too afraid to show me an integral, so it uses 5 paragraphs instead. I was just curious in general. EagleFalconn ( talk) 14:08, 8 August 2008 (UTC)
Regarding Scifinder access at home, while you're at the library you might want to speak to the librarian about it. At Purdue, we use a program called Citrix which allow us to login to the library servers and remotely use SciFinder. It might be worth seeing if Leeds has something similar. The reason Purdue has it is because SciFinder use is so expensive that its cheaper to offer this remote service and simply restrict the number of people who can use it at any given time than it is to try some other distributed method. Have a good weekend. EagleFalconn ( talk) 14:54, 8 August 2008 (UTC)
I have a little crazy question. I´m a german student and I have to write an english abstract about my work with FTIR. The problem is that I don´t know a native speaker to read it and my english is only enough to communicate. I saw you comment the english article about FTIR and so I pluck up my courage and ask you. It is half a page, so I perhaps could place it here. About help I would be VERY greatful!!! Claudia -- 80.132.234.231 ( talk) 23:19, 27 September 2008 (UTC)
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There is some discussion at Wikipedia talk:Accessibility#Equilibrium_symbol that you may find of interest. -- Itub ( talk) 15:53, 17 October 2008 (UTC)
Peter, I was about to update my comments at Wikipedia:Featured article candidates/Acid dissociation constant when I noticed that Sandy had just archived it, so it appears it will be not be promoted this time around. I'll add my responses to your changes to the article talk page, so that you can follow them up if you wish. My feeling is that the content of the article is in good shape; all that is needed is to fix some of the stylistic and layout issues and it will have a much better chance. More at the article page. Mike Christie (talk) 23:09, 25 October 2008 (UTC)
Hi, Petergans. I agree with Mike that the article is well on the way; I've left some sample edits of issues that will help bring it over the hump. (Please review each of my edit summaries to understand the invidividual issues, including WP:ACCESS, WP:DASH, WP:MSH, how to write citations correctly, WP:MOSDATE#Precise language, etc.) Per your comment on my talk page: If this were a peer-reviewed journal, I would expect the editor to make a final decision regarding publication on the basis of whether the author(s) have responded adequately to the referees' comments. I assume that a similar process applies in WP. Unfortunately, unlike a peer-reviewed journal, we don't have paid staff members, and we must rely on volunteers who donate their time to review articles. When a nomination has been at FAC for two weeks, and hasn't gained consensus for promotion, it can become harder to entice reviewers to revisit, and a clean start once issues are addressed is often the fastest path to featured status. In this case, few reviewers had engaged, and the FAC commentary indicated a lot of work remaining; a clean start in a few weeks after all of these issues are dealt with is likely to yield the best outcome and attract more reviewers to Support. With Mike Christie on board, you should be in good shape: please renominate whenever Mike concurs it's ready (including the sample edits I left). SandyGeorgia ( Talk) 21:53, 26 October 2008 (UTC)
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Hi...Thanks for adding a reference to the phase diagram article. I also see that you added a note saying that it covered most of the text in the article. If this is the case could you added page numbers for each paragraph, similar to the way the references are in the forging article, that way others can confirm it. Thanks! Wizard191 ( talk) 14:19, 20 November 2008 (UTC)
I'm not clear what the real issue is here. Let me put it this way: all the diagrams in the article are famililiar to me from various physical chemistry text-books, going back to when I was an undergraduate, 50 years ago. In other words, this is "common knowledge". As it happens we've just been discussing the issue of common knowledge in chemistry at Talk:Acid dissociation constant in the process of getting that article promoted to featured article status. I suggest you also look at wp:SCR. For me, it's difficult to see the need to supply specific references to verify things that have been common knowledge for more than a century. [ book review]. This book is still available! Petergans ( talk) 19:27, 20 November 2008 (UTC)
Welcome!
Hello, Petergans, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:
I hope you enjoy editing here and being a
Wikipedian! Please
sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out
Wikipedia:Questions, ask me on my talk page, or ask your question and then place {{helpme}}
after the question on your talk page. Again, welcome!
Nimur
09:11, 19 March 2007 (UTC)
Hi Peter. It looks like you put two really good articles on your user page. Do you want me to split them up into subpages for you? That way you can have both drafts in your userspace to edit as you please. -- HappyCamper 18:36, 14 April 2007 (UTC)
Hi Peter - Somebody gave me a link to a Word to MediaWiki converter: [3]. I've never experimented with it before, but it might work. As for item two, I don't think there is an editorial standard on Wikipedia yet. Go with what's easiest to use for now. As for the templates, feel free to edit them. There is this policy which governs this. Personally, I'm aiming to be even more ambitious and make a navigational template similar to Template:Physics-footer. It would be really great to organize all the chemistry articles in this way. -- HappyCamper 19:10, 26 April 2007 (UTC)
Hi Peter - I thought it might be better to make a new section here since we'll be talking mostly about your draft. I'm glad the Word macro worked out well. I don't think it's possible to render the math equations with smaller font. Generally, if the equation is "sufficiently complicated", it will be rendered with the larger TeX font. If you click on "my preferences" in the top right hand corner of your screen, there might be a better local setting for your computer. The full path to your draft is User talk:Petergans/draft, so [[User talk:Petergans/draft]] will refer to it. The [[/draft]] notation is just a shortcut way of referring to subpages. In other words, if you were editing on say, Talk:Equilibrium constant, the [[/draft]] page would actually refer to [[Talk:Equilibrium constant/draft]]. -- HappyCamper 04:02, 29 April 2007 (UTC)
Thanks for your message. I have to keep this response brief for now, but I'll come back with more when I get the chance to.
I've added some comments to your help desk question. - Mgm| (talk) 22:31, 8 May 2007 (UTC)
It's probably easiest to do this by example. Click on Agamenon (which is a misspelling). It will redirect you to the correct article. In the upper left hand corner, you should see a tiny blue link that says "(Redirected from Agamenon)". It should be right under the article title. If you click on this page, you will get to go back to the original location of the redirect - and naturally, you'll be able to edit this page. -- HappyCamper 16:29, 9 May 2007 (UTC)
If you're talking about the interwiki links on the bottom of the article, they work differently in the user space than they do in the mainspace. They're formated correctly, and when the article is moved to mainspace they will work as expected. I'll remove the helpme, but please put it back if this does not answer your question. Cheers, ➪ HiDrNick! 13:30, 10 May 2007 (UTC)
I hope I've helped a bit. One thing about the draft. 2 citations in an article this size is too little. See if you can use any of the general reading entries as a reference and make sure you provide a citation to back up the definition you give in the very first line. Also "as the reaction is driven to the left" may need a more overt wording explaining exactly which particles react to become what to restore the balance. - Mgm| (talk) 10:05, 11 May 2007 (UTC)
So you removed my square brackets. I have to say that I disagree with you, and just because thy're not in the hydronium article doesn't make it right. Maybe I'll sneak them back in when you're not looking.
As for [HF2- being a three centre, two electron bond... Thinking about it, I think it's actually a three centre, four-electron bond, as the non-bonding three centre MO is filled as well as the bonding one. I've not come across such a thing before though; I'll look it up tomorrow. If you think about it as HF hydrogen bonded to F-, it's obvious where the four electrons come from. Chris 17:59, 14 May 2007 (UTC)
Thanks for your message. I saw that you were at Leeds and figured you might know them. I remember the late great Ron Snaith telling me once that one of them (I forget which) was his father in law, and that I had to buy the book because he needed the money :)
I changed the bonding in [HF2- to 3c-4e; the references there are very clear that this is the correct desciption.
Incidentally, I think this : ⇌ looks better than this:
Cheers, Chris 20:21, 14 May 2007 (UTC)
I left a response at Wikipedia:Requests for feedback to your question on Reversable Chemical Processes. Please read it over and let me know if it makes sense. -- Jayron32| talk| contribs 05:18, 15 May 2007 (UTC)
It's always a joy to see other inorganic chemists out there; so many people tend to go towards organic chemistry as i have in the past, but find myself drawn more to inorganic and physical :-). Thanks for coming to wikipedia, hope you decide to edit lots here! ♥♥ ΜÏΠЄSΓRΘΠ€ ♥♥ slurp me! 20:16, 23 May 2007 (UTC)
I'm sorry for the lack of response on my part, but I have been busy with other things. You could ask the nice guy who posted above me to help out, but if that doesn't work, I suggest talking to the Wikipedia:Mediation Cabal. If the person in question keeps reverting without any sort of discussion, you're doing nothing wrong in reverting him as long as you try to initiate discussion. - Mgm| (talk) 08:25, 29 May 2007 (UTC)
You are right, it is not correct to say time-derivative. I was fully aware that it was a mistake, but I thought it would simplify the writing. In hindsight, it was a mistake. I've corrected it. Loom91 20:54, 4 June 2007 (UTC)
After some delay due to travel I have replied to your questions in my talk page. -- Itub 07:14, 5 June 2007 (UTC)
If you want attention from an administrator, please ask for attention from another administrator. At the moment I am too busy to help you out. WP:AN or WP:ANI should be helpful. - Mgm| (talk) 17:24, 20 June 2007 (UTC)
Thank you for your contributions to the Activity coefficient article; it is much the better for it. I think, however, I have espied an error.
You wrote, "As concentrations tends to zero, activity coefficients tend to one, so in very dilute solution, activity is equal to concentration." (I have taken the liberty of adding two commas).
Shouldn't it instead read "As concentrations tend to one..."? Since according to the equation,
if were zero, would be -∞. One the other hand, if referred to the mole ratio of the solvent instead of a solute, would correspond to a dilute solution. This would give the desired result
Or am I misunderstanding something?
Upon further consideration, I realize that it's not whether a particular substance is a solute or a solvent that counts--the distinction fades to nothing when both substances are infinitely miscible--but whether or not they are pure. I'm going to go ahead and change the article to reflect this. Please feel free to revert me if you think I'm making a mistake.
I feel that my last statement requires a clarification. There is at least one property that does depend on whether a substance is a "solute" or a "solvent": the activity coefficient of the substance that is nearly pure approaches one; the activity coefficient of the substance that is greatly diluted does not. Sorry to clutter up your talk page with my ramblings :)
Hi, I just wanted to thank you for suggesting reorgaizing the least squares related articles and in doing it in such a smart way (on a talk page, and giving people lots of time to respond) I disagree with Oleg's comment on your push for consistent notation, I think it's great that you are thinking of the project as a series of articles, not just a few here and there. Pdbailey ( talk) 16:49, 24 January 2008 (UTC)
Hello Petergans! A number of mathematics editors have been discussing the Least squares article. You are welcome to add your own comments there. EdJohnston ( talk) 18:29, 31 January 2008 (UTC)
I moved User:Petergans/b/sandbox to Non-linear least squares. Thank you for the fine work. However, I would disagree with merging Gauss-Newton algorithm to it, and other people seem to echo my sentiments that such a merge would make things harder to understand.
I also further commented at Wikipedia talk:WikiProject Mathematics. My suggestion there is that we attempt to make linear least squares easier to understand before attempting further rewrites.
You can reply here if you have comments. Cheers, Oleg Alexandrov ( talk) 04:16, 1 February 2008 (UTC)
I see that you are still working on this article in your sandbox. I think if you want to contribute to that article you should edit the Linear least squares article directly rather than keeping a parallel version in your sandbox, and we should discuss any differences. Wonder what you think. You can reply here. Thanks. Oleg Alexandrov ( talk) 04:41, 8 February 2008 (UTC)
The reason for doing this is is that I have been trying to achieve consistency between least squares, linear least squares, non-linear least squares, Gauss-Newton algorithm and eventually some of the related articles. This was the purpose outlined in my major proposal. I know you don't approve of "grand projects", but I see this rather as a tidying up operation. If I had worked on the article directly some of the changes would not have made sense.
Regarding linear least squares, I have said that some of your recent edits were unacceptable. This is very strong criticism and I stick by it. To me your latest definitions section is very hard to understand, even without norms. My new version uses simple algebra which should be much more accessible to non-mathematicians.
As it happens I am going live today with all four revised articles, with a note of explanation on Talk:Least squares. I am suggesting that general comments be made there, but comments specific to each article be made on the respective talk pages, where I will also place notes.
Incidentally this is the dictionary definition of objectionable: unpleasant, offensive or repugnant. I know you meant to imply that it was something to which you objected, and I let it pass as English is not your mother tongue, but I thought you should know.
Petergans ( talk) 09:09, 8 February 2008 (UTC)
I wrote a comment on the rewrite of that article at Talk:Gauss-Newton algorithm#Response to rewrite. Oleg Alexandrov ( talk) 03:25, 9 February 2008 (UTC)
The section about the oxidation state of iron in oxyhaemoglobin is wrong. It is now known that it is low-spin Fe(II). See Greenwood and Earshaw, Chemistry of the Elements 2nd edition, pp 1099-1100. The key point is that in deoxy-Hb the high-spin Fe(II) is too large to enter the plane of the porphirin ring (Figure 25.7) but when oxygen binds the low-spin Fe(II) enters the plane as it is small enough. The paramagnetism of O2 is destroyed because the Fe-O2 angle is 120o, so the pi-star orbitals are no longer doubly degenerate.
I'm not a biochemist, so I hesitate to edit the article myself. Petergans 09:56, 11 May 2007 (UTC)
Sorry but I'd prefer not to enable email – i wouldn't mind receiving an email from you, but I don't want anyone on wikipedia to be able to email me. I'd rather conduct conversations on talk pages (whether article or user - decided to move this to your User talk page as it seems to be a 2-party conversation at the moment). I think something's wrong with your regression results. It could just be the units. But in results of the last model in the example (without the linear term in height) the coefficient of x2 is clearly inconsistent with the graph. I've just rerun the model in my favourite statistical package ( Stata) and got this:
. regress weight height2 Source | SS df MS Number of obs = 15 -----------+------------------------------ F( 1, 13) = 2208.52 Model | 689.315143 1 689.315143 Prob > F = 0.0000 Residual | 4.05750798 13 .312115998 R-squared = 0.9941 -----------+------------------------------ Adj R-squared = 0.9937 Total | 693.372651 14 49.5266179 Root MSE = .55867 ---------------------------------------------------------------------------- weight | Coef. Std. Err. t P>|t| [95% Conf. Interval] -----------+---------------------------------------------------------------- height2 | 18.60872 .3959729 46.99 0.000 17.75327 19.46416 _cons | 11.14818 1.093288 10.20 0.000 8.786274 13.51009 ----------------------------------------------------------------------------
This appears more consistent with the graph. Qwfp ( talk) 20:24, 2 March 2008 (UTC)
I agree, it's not an ideal illustration. The motivation for plotting with ht2 on the x-axis was to illustrate the fact that w/ht2 is not constant, but the variable choice is potentially confusing. The model y = a + b ht+ c ht2 is also adequate, as was the original cubic. Can you suggest a better data set? We need a system for which there is a good reason to expect that a quadratic will fit the data. Petergans ( talk) 17:50, 3 March 2008 (UTC)
Couldn't find anything useful there, so I've finally settled a quadratic model . That's me done with this article. From now on it's up to others to improve it. Many thanks for your correspondence, it has been really useful. Petergans ( talk) 15:08, 4 March 2008 (UTC) /* Linear regression Example: heights and weights */ ::I had a quick look and that's certainly clearer. I appreciate all the work you've put into this article. Regards, Qwfp ( talk) 17:21, 4 March 2008 (UTC)
Check out what I've put in the talk page as descriptions of the mean and predicted response. I'm sure the language can be refined somewhat, but it explains the concepts and gives the start and end of the derivation :) Velocidex ( talk) 04:07, 11 March 2008 (UTC)
I wonder if you have any comments regarding my comment at Talk:Gauss-Newton algorithm. I have my own proposal for a rewrite, but I wonder what you will say first. Thanks. Oleg Alexandrov ( talk) 02:28, 12 March 2008 (UTC)
Dear Peter, I recently proposed starting a "probability and statistics" sub-project (aka task force or work group) of WikiProject Maths and was wondering if you'd be interested in participating. If so, please add your name and any comments at WP:WikiProject Council/Proposals#Probability and statistics. Regards, Qwfp ( talk) 21:57, 12 March 2008 (UTC)
Peter, I wonder if you could comment on the recent discussion on Gauss-Newton. What you've been claiming about the data-fitting application having better convergence properties is wrong, the algorithm can fail even for data fitting, and the second derivative of data-fitting residuals may not be zero even at the minimum.
The plan is to merge the two sections on convergence, as the properties of the algorithm are the same in data fitting as in the general case. Please state your objections there. Oleg Alexandrov ( talk) 15:23, 17 March 2008 (UTC)
Hi Peter, we seem to have made large edits simultaneously on ADC. I'm currently in the process of resolving the edit conflict by integrating my changes into your version, please hold until my next edit save. It shouldn't take more than 10 or 15 minutes. EagleFalconn ( talk) 14:08, 23 July 2008 (UTC)
Follow up question to this: In the new lead you use pK frequently when discussing applications. Should this remain pK or for the sake of consistancy within the article, is it correct to change those to pKa? EagleFalconn ( talk) 14:14, 23 July 2008 (UTC)
Howdy, I'm looking at listing Acid Dissociation Constant on WP:FAC. Any reason for me to wait? EagleFalconn ( talk) 16:54, 4 August 2008 (UTC)
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I mean this in the best possible way, but out of curiosity do you just have a library of relatively old chemistry books sitting around in your office or at home? Every time you reference a book it seems to come from the pre-1980s, and I'm curious where you're finding them. EagleFalconn ( talk) 13:51, 8 August 2008 (UTC)
I've got no problem with old books -- I'm frequently dissatisfied with a lot of my textbooks in school because they focus on pictures instead of rigor. Prime example would be my physical chemistry book...too afraid to show me an integral, so it uses 5 paragraphs instead. I was just curious in general. EagleFalconn ( talk) 14:08, 8 August 2008 (UTC)
Regarding Scifinder access at home, while you're at the library you might want to speak to the librarian about it. At Purdue, we use a program called Citrix which allow us to login to the library servers and remotely use SciFinder. It might be worth seeing if Leeds has something similar. The reason Purdue has it is because SciFinder use is so expensive that its cheaper to offer this remote service and simply restrict the number of people who can use it at any given time than it is to try some other distributed method. Have a good weekend. EagleFalconn ( talk) 14:54, 8 August 2008 (UTC)
I have a little crazy question. I´m a german student and I have to write an english abstract about my work with FTIR. The problem is that I don´t know a native speaker to read it and my english is only enough to communicate. I saw you comment the english article about FTIR and so I pluck up my courage and ask you. It is half a page, so I perhaps could place it here. About help I would be VERY greatful!!! Claudia -- 80.132.234.231 ( talk) 23:19, 27 September 2008 (UTC)
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There is some discussion at Wikipedia talk:Accessibility#Equilibrium_symbol that you may find of interest. -- Itub ( talk) 15:53, 17 October 2008 (UTC)
Peter, I was about to update my comments at Wikipedia:Featured article candidates/Acid dissociation constant when I noticed that Sandy had just archived it, so it appears it will be not be promoted this time around. I'll add my responses to your changes to the article talk page, so that you can follow them up if you wish. My feeling is that the content of the article is in good shape; all that is needed is to fix some of the stylistic and layout issues and it will have a much better chance. More at the article page. Mike Christie (talk) 23:09, 25 October 2008 (UTC)
Hi, Petergans. I agree with Mike that the article is well on the way; I've left some sample edits of issues that will help bring it over the hump. (Please review each of my edit summaries to understand the invidividual issues, including WP:ACCESS, WP:DASH, WP:MSH, how to write citations correctly, WP:MOSDATE#Precise language, etc.) Per your comment on my talk page: If this were a peer-reviewed journal, I would expect the editor to make a final decision regarding publication on the basis of whether the author(s) have responded adequately to the referees' comments. I assume that a similar process applies in WP. Unfortunately, unlike a peer-reviewed journal, we don't have paid staff members, and we must rely on volunteers who donate their time to review articles. When a nomination has been at FAC for two weeks, and hasn't gained consensus for promotion, it can become harder to entice reviewers to revisit, and a clean start once issues are addressed is often the fastest path to featured status. In this case, few reviewers had engaged, and the FAC commentary indicated a lot of work remaining; a clean start in a few weeks after all of these issues are dealt with is likely to yield the best outcome and attract more reviewers to Support. With Mike Christie on board, you should be in good shape: please renominate whenever Mike concurs it's ready (including the sample edits I left). SandyGeorgia ( Talk) 21:53, 26 October 2008 (UTC)
This is an automated message from CorenSearchBot. I have performed a web search with the contents of Osmotic coefficient, and it appears to include a substantial copy of http://goldbook.iupac.org/O04342.html. For legal reasons, we cannot accept copyrighted text or images borrowed from other web sites or printed material; such additions will be deleted. You may use external websites as a source of information, but not as a source of sentences.
This message was placed automatically, and it is possible that the bot is confused and found similarity where none actually exists. If that is the case, you can remove the tag from the article and it would be appreciated if you could drop a note on the maintainer's talk page. CorenSearchBot ( talk) 14:40, 15 November 2008 (UTC)
Hi...Thanks for adding a reference to the phase diagram article. I also see that you added a note saying that it covered most of the text in the article. If this is the case could you added page numbers for each paragraph, similar to the way the references are in the forging article, that way others can confirm it. Thanks! Wizard191 ( talk) 14:19, 20 November 2008 (UTC)
I'm not clear what the real issue is here. Let me put it this way: all the diagrams in the article are famililiar to me from various physical chemistry text-books, going back to when I was an undergraduate, 50 years ago. In other words, this is "common knowledge". As it happens we've just been discussing the issue of common knowledge in chemistry at Talk:Acid dissociation constant in the process of getting that article promoted to featured article status. I suggest you also look at wp:SCR. For me, it's difficult to see the need to supply specific references to verify things that have been common knowledge for more than a century. [ book review]. This book is still available! Petergans ( talk) 19:27, 20 November 2008 (UTC)