User talk:Jerry-va

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User_talk for jerry-va[edit]

Hi, please leave new comments at bottom.



Hello, Jerry-va, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are a few good links for newcomers:

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:Where to ask a question, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome! --Srleffler 21:38, 26 February 2006 (UTC)


I am concerned that Wikipedia's increasing erudition sometimes brings obscurity and impenetrability. I would welcome "Getting Started" sections that kick off more entries with an overview. I would like to see more sentences at the end of paragraphs that begin with words like Summary: or In conclusion,.

One of the problems with Wiki info is that the editing procedure treats subject matter discussion in the same way regardless of its relationship with nature. So if you can find "authoritative references" you can argue anything you want about any subject matter you want, and mix it all up on the same page. So as a source of important information, which it is a lot, you've got to do a lot of sifting to come up with a cohesive discussion of most scientific subject matters.WFPM (talk) 12:21, 17 April 2010 (UTC)

"How To" Hobby Info Must Go Elsewhere[edit]

Wikipedia is understandably concerned more with "What is this thing?" than with "How to perform this process", accomplish this task, acquire and practice this skill, get something done or make it work. Where does this leave hobbies? If you know of some Wikipedia "hobby" and "how to" pages that might be a good example for us all, please list them so we can all have a look. How about these: "How to sharpen a handsaw" "How to build a Universal Power Supply" "How to tell if a transistor is blown" "How and why to prune fruit trees" "Tips for growing tomatoes" "Practical composting"

Thanks!!   —Jerry-va 20:19, 26 February 2006 (UTC)

I believe this was a policy decision. See Wikipedia:What Wikipedia is not, where it says:
Instruction manuals - while Wikipedia has descriptions of people, places, and things, Wikipedia articles should not include instruction - advice (legal, medical, or otherwise), suggestions, or contain "how-to"s. This includes tutorials, walk-throughs, instruction manuals, video game guides, and recipes. Wikibooks is a Wikipedia sister-project which is better suited for such things. Note that this does not apply to the Wikipedia: namespace, where "how-to"s relevant to editing Wikipedia itself are appropriate, such as Wikipedia:How to draw a diagram with Dia.
Srleffler 17:34, 27 February 2006 (UTC)

Guys who own the page are not Gals[edit]

Territoriality. Have you noticed that the revisions of many pages are dominated by one person? And this person is often a guy? The author imagines he owns the page -- it is his territory, he defends it. Such Territoriality is important for higher organisms, birds as well as mammals -- the adaptive radiation that drives evolution often begins with staking out a territory, and it is often the male that guards the fort.

Gender Bias. Why are there so many fewer female contributors to Wikipedia? How can we make Wikipedia authorship more representative of the proportion of females to males in the population at large, rather than representative of the differences in female vs male behavior in the species as a whole? Please put this question of page domination to a gender-balanced sample of Wikipedia community contributors.

Women operate more by consensus and less by hierarchical standing. So perhaps after the recurrent territorial defender of a page has executed 6 undos by another contributor, it should be necessary to ask and get permission from someone else who has edited the page before doing a 7th undo. (Lift the restriction automatically after, say, 6 months.) Perhaps this leads to more consensus, lessens the absoluteness of power, doesn't appeal to anyone who wants page dominance perhaps more than s/he wants page quality, page community, page evolution. I have written at least one document that is cited as a source in the Wikipedia, originated a minor Wiki article, but, where I sense these social attributes, I am repelled from contributing to the Wikipedia.
Jerry-va (talk) 22:58, 9 December 2011 (UTC)

Lens aperture[edit]

Can you provide some enlightenment about both effective lens aperture (entrance pupil) and effective focal length? You might mention "nodal point" "retro-focus" and other concepts from both modern lens design magic and basic optics. Here's the problem: it has become impossible for me to tell if a lens's stated specs are either plausible or consistent with one another. I can understand that focal length is not the distance from the rear element to the image plane in a 13-elements-in-7-groups lens. The optical "middle" of the lens (presumably a nodal point from a ray diagram point of view???) is, well, somewhere in middle. But the aperture is even more baffling. For example, most zoom lenses today do NOT become as slow as they "should" be at longer focal lengths. What is left at the practical level for an every-day check anyone can perform? I presume that, if one accepts that one camera lens has a 60mm FL than an unknown lens producing an image in which the same objects have half the linear size has half the focal length. Any other sanity checks? Thanks, the technology is really getting away from me. -- Jerry-va 18:53, 26 February 2006 (UTC)

I understand your confusion. I may be able to help some, but I'm not a photographer nor do I design camera lenses. (I do design lasers, so I know something about optics.) The focal length of any lens is the distance from the rear principal plane of the lens to the focal plane (where the film or CCD goes when you're focusing at infinity). For a simple thin lens, the rear principal plane will be near the center of the lens. For a complicated multi-element lens, the principal plane could be anywhere. In particular a telephoto lens is, technically, one where the optics are designed to put the principal plane somewhere out in front of the lens, which means that the lens can be shorter than its focal length. Note that it has become common to call all long-focus lenses "telephoto" but this is not technically correct. It is possible to make a non-telephoto long-focus lens. It would just be very long. A retro-focus lens is the reverse of a telephoto lens: the rear principal plane is closer to the film than the nearest element, allowing the rear element of the lens to be further from the film than would otherwise be possible. This allows the construction of very short focal length lenses that can be used with a standard SLR body.
If you're taking photos in air and there is air inside the camera, the rear nodal point is at the same location as the rear principal plane. Nodal points don't appear to be well understood in photography, though. There seem to be a number of misunderstandings about what happens to light at the nodal point. I don't think I can address these here.
Another thing to be cautious of: manufacturers of digital cameras don't always report the focal length accurately. For example, the digital camera I have here says "37mm-111mm (Equiv)". The "Equiv" is there because the focal length range of the zoom lens in this camera is not actually 37-111 mm. Since the CCD in a digital camera is much smaller than a 35 mm film frame, the focal length required to take a photo with a normal field of view is much smaller. Rather than report the actual focal length of the lens, though, they give the focal length of the lens that would produce the same field of view on 35 mm film, and mark it "equiv". Personally, I think this is terrible and leads to unnecessary misunderstandings. I guess photographers like it, though, because it helps them quickly decide whether a lens is normal, long-focus, or wide-angle.
I'm not sure exactly what is confusing you with apertures, but I can guess. Besides misreported focal lengths on digital cameras, many photographers believe that the f-number is the ratio of the focal length to the diameter of the physical diaphragm opening. This is not true. The f-number is the ratio of the focal length to the diameter of the entrance pupil, which is an image of the diaphragm, formed by the lens elements in front of it. If you can open the shutter and see the diaphragm, you should be able to get a rough idea of the entrance pupil size by looking into the front of the camera and observing how big it appears. It may appear much bigger or smaller than the actual opening, due to the magnification of the lens elements. It just depends on the design of the lens.
Hope this helps. Feel free to ask more questions.--Srleffler 21:35, 26 February 2006 (UTC)

Praise for a good intro[edit]

My thanks for a truly excellent opening. Several key concepts are mentioned. Each is related in turn to the previous operation/change/fact. The relation is logical and answers questions a curious reader might have.

If the reader is thinking, "And then, what?" or "So what, and why does **that** matter?" then the reader will find that the answers flow naturally in the next statement. No vanity, no showing off that we all know there are exceptions to general assertions, just the basics first.

Relating one basic concept to another -- even if it takes you beyond the definition of the encyclopedia entry-point -- provides the synthesis and the overview that beginning readers lament the lack of in other science articles, articles that unfortunately plunge too quickly to the contentious, detail-laden forefront of any research area.

These concepts that provide synthesis and overview, that answer the beginner's "So what, what next?" concerns, may each have their own Wikipedia page, but that does not mean the concept's relationship cannot be mentioned here. Rather, it confirms the importance of reaching out to tie in a related idea/consequence/effect. In sum, good job. It is impossible to see at a glance from the edit log who the talented (and humane) major contributors are, so I thank the community.
Article: Endonuclease as of 12/2011
Jerry-va (talk) 12:56, 28 December 2011 (UTC)

Ex Cathedra[edit]

The Messier 87 article struck me as a collection of facts showing little understanding of the how science was done, little mention of where the facts come from and what they imply, of what the underlying processes are, and how any of this relates to other things we know or that the reader might understand. Alas, my criticism was too harsh to be helpful. M87 is a galaxy like ours containing the most massive black hole in the nearby universe. It gives us a look at how the gravity from such black holes (vs from dark matter) organizes the thousands of globular clusters associated with spiral galaxies, as well as giving us a look at black hole phenomena such as their axial jets.

This article is appalling in its relentless assertions about M87 made without relating how the science was done, without stating how one thing was inferred from another. At the very least, it is a wasted opportunity to achieve excellence for the Wikipedia. Is it a good article that simply could be better? No. This article damages science and scientists. "M87" as written is an example of science as take-it-or-leave-it authoritarianism. The adventure of discovery is missing, the failure to relate how knowledge evolved or where it came from slights the role of M87 itself in the history of astronomy, the use of rational thought to make connections that have validity and consistency is not illustrated, the way in which knowledge now presented ex Cathedra actually grew in certainty, that also is missing. Worst of all, the idea that our understanding is incomplete -- some shred of humility before Nature -- is missing. Yes, this is a good summary of what we know at this time, but I never treated my graduate students this way. IMHO, Wikipedia at its best is not just a snapshot in time of where we are, it is also a hand extended to others to carry on and contribute.
Jerry-va (talk) —Preceding undated comment added 22:10, 26 March 2012 (UTC).

Well it's unfortunate that you think so, but to me your opinion smells distinctly of flame bait. For that reason I'm not going to pursue this further. Regards, RJH (talk) 22:25, 26 March 2012 (UTC)
That was pretty harsh criticism, but I will refrain from expressing my opinion because of WP:CIVILITY. All I can say is, if you can make the article better within the framework of Wikipedia guidelines, then I suggest you do so. Any interest I have in cooperation in the matter is gone. Bye. RJH (talk) 22:39, 26 March 2012 (UTC)
You acknowledge that the article is "a good summary of what we know at this time." I disagree with your view that Wikipedia should aspire to be more than this. It's an encyclopedia, not a collection of treatises. Overly rambling and ambitious articles actually defeat the purpose of giving the reader a concise introduction to a topic. --Yaush (talk) 17:39, 27 March 2012 (UTC)

Praise for a successful teaching article: Brillouin Scattering[edit]

Why did the article on Brillouin article suddenly make so much so clear for me? Here are my two bits on what makes a good teaching article, as posted in praise to the article's own Talk page.

This is a great little article. Too bad it will never be recognized as a "Featured Article" because of its modest size. Yet it has great teaching value and didactic excellence. A reader can learn from it.

We will never see comments like these that readers took the trouble to make for another article:
1. "... the rest of us have no idea what you're talking about."
2. "Huh^2. I'm a math/s graduate and I haven't the faintest clue what this article is about."
3. "I have an undergrad degree in mathematics and this is all Greek to me. . . . The article is completely inaccessible to the layperson."
4. " I have degrees in both math and physics and have no idea what this article is talking about."
5. " I understand, to some reasonable degree, both of einsteins theories, i got an 800 on my math sat, and i have absolutely no idea what this article is about."

The Brillouin Scattering article succeeds. What can we learn from it? Why is this article so useful?

IMHO, two characteristics give this article excellence in helping others learn:


Just because we have hyperlinks to other articles, we should not shrink from making comparisons to -- and drawing attention to differences from -- other related concepts. It is permissible to clarify for readers and for ourselves the similarities and differences with other items -- other physical effects, other political philosophies, a competing conceptual construct -- even if those items have their own articles. Sending a reader on a page bounce pales in comparison to the teaching that editors can achieve for the community through their clarification of competing concepts.


For teaching readers, it is OK to present multiple conceptualizations of an effect or named "thing", rather than to insist on crafting the most "correct" one. For example, the scattering of light by matter is caused by inhomogeneities, and these may be viewed as subwavelength particles (dust makes the sky blue), or individual molecules (that absorb or impart energy), or variations seen as density differences or refractive index differences, whose interactions are either quantized or not, are electromagnetic or not (phonons).

There is a third issue: how an article opens.


A definition is an obvious start, right? No so fast.

This brief Wikipedia article on Brillouin Scattering has illuminated how light is scattered by matter, and, in doing so, has shed light on Brillouin, Raman and Raleigh scattering. This is not the same as struggling to craft the least objectionable definition of each one. Such "least objectionable definitions" must often be general; to be general, specifics must be omitted; without specifics, the reader gets less information.

It may sometimes be necessary to begin with a "loose", more basic definition, and then refine it, then develop the exposition. There will be exceptions to a basic definition which invalidate it, which make it wrong in some cases. We can deal with this, don't worry. Editors who struggle to achieve a definition that handles all objections -- the least objectionable definition -- deprive themselves of a natural way to develop the entire article, to carry the article from the broad to the specific. And, the Least Objectionable Definition -- to those who know what they are talking about -- may become useless to those who have come here to learn.

This article helped me, and I thank all of you.  :-) (21Oct2012)
Jerry-va (talk) 13:44, 21 October 2012 (UTC)