Depth-First: Category Meta

The Daily Molecule: The Wonders of Chemistry - One Molecule at a Time

Rich Apodaca — Wed, 14 May 2008 11:58:00 -0400

Chemistry is a big field judged by any standard, including the proliferation of American Chemical Society (ACS) divisions. Each subdiscipline in chemistry is in turn so big, that once a chemist becomes 'differentiated' it's easy to lose touch even with neighboring subdisciplines. It doesn't have to be that way. This article introduces a new service, The Daily Molecule designed to make it just a little bit easier (and hopefully fun) to stay in the chemical loop.

What Is It?

The idea is simple: every weekday, a new molecule will be featured on The Daily Molecule with a short write-up and some leading references. Although molecules in the news will get first priority, any molecule is fair game.

The material for The Daily Molecule will be drawn from Chempedia, which in turn gets some of its content from Wikipedia. In other words, the entries on the Daily Molecule will be largeley written by my fellow chemists.

The process of creating a Daily Molecule entry is not time-consuming, but much of what is being done manually now could be automated in the future. The technology platform lends itself well to many forms of chemistry-specific modification (see below).

I hesitate to use the term 'blog' to describe The Daily Molecule, but the description may be helpful to an extent.

The Daily Molecule is unlike a blog in that most content will be generated by others, selected by some criteria, reformatted for consistency, and published. In that sense, The Daily Molecule is a something like a mini scientific journal, but it turns the process of acquiring content on its head.

If chemistry ever evolves beyond the current model of publication, which seems inevitable at this point, the journals of the future may resemble The Daily Molecule in one or more ways.

Technology

The software running The Daily Molecule is a modified version of SimpleLog, a Web application based on Ruby on Rails. Unlike most blogging engines, SimpleLog focuses on implementing only the most basic publication features, and doing them to perfection. If you know a little Ruby and can work with Rails, you can do a lot with SimpleLog.

One of the first items of business will be to implement reCAPTCHA support and activate comments on articles.

Some ideas for chemically-enabling The Daily Molecule include a graphical abstract sidebar and (sub)structure search. Currently, the 2D chemical structure images posted to The Daily Molecule have complete connection tables embedded as metadata, a feature with some interesting possibilities.

The Molecule of the Day/Week/Month

The basic idea behind The Daily Molecule is not new. Many other services have sprung up over the last ten years that operate, at least on the surface, similarly. Some examples:

Molecule of the Day
ACS Molecule of the Week
Drugs and Poisons
Saturday Night Synthesis
The Molecule of the Month (may be the oldest continuously-operated MOTM site in existence)
3dchem.com Molecule of the Month
Protein Spotlight
PDB Molecule of the Month
Prous Molecule of the Month

Quite a few others don't appear on this list.

The different idea behind the The Daily Molecule is that chemical content already exists in on the Web in machine-readable format with licenses that permit its re-use; all that's needed is a way to aggregate, format, and package that information in a form suitable for once-daily scanning and cheminformatics manipulation.

Conclusions

Like no other medium, the Web blurs artificial distinctions: between work and play; between private and public; between on-topic and off-topic; between fame and obscurity; between mine and yours; between big and small; and between profit and non-profit. Chemistry may be late to the party, but is not immune to its call.

Building Chempedia: Start Simple, Then Iterate

Rich Apodaca — Tue, 13 May 2008 11:38:00 -0400

As a medium for building software, the Web offers unparalleled adaptability. With nothing to download or install, users of Web applications automatically see the newest version - always. This may sound like a small thing, and technically it is. But it dramatically increases the effectiveness with which software can be created. The previous article in this series introduced Chempedia, the free Chemical encyclopedia and cheminformatics Web application. This article will discuss the process by which Chempedia will become a better service over time.

Iterative Web Application Development

Chempedia, like all actively-developed software, is a work in progress. It will be built in stages starting with the addition of new features, followed by a round of user feedback, bug fixing, and stabilization. This will then be followed by the next major iteration, and so on.

This iterative design style is ideally suited for Web applications. Because the barrier to pushing out new versions is essentially non-existent, a Web application can evolve at a much more rapid rate than other kinds of software. Indeed, the first version of a Web application need only work well enough to prove a point.

One of the keys to iterative Web development is a technology framework designed to facilitate it. Chempedia is being developed with Ruby on Rails, a tool that enables Web developers to take full advantage of the iterative development style the Web makes possible.

Another key element of iterative Web development is users willing to explore the system and offer criticism. Evolution succeeds only when the environment stresses an ecosystem; the same is true in Web application development.

Chempedia will take full advantage of the evolutionary nature of Web application development. As features are added and (hopefully) use of the service grows, Chempedia will evolve in ways that are impossible to predict today.

What's Wrong With Chempedia?

If you happened to take a look at Chempedia last week (that version is now no longer visible), you probably noticed many, many things that needed improvement. Some concerns were in the areas of:

Navigation. Navigation works best when the right granularity of options is achieved. Chempedia's navigation system grouped both closely-related and dissimilar actions at the same level.
Metaphor. The initial idea behind Chempedia was to see what happened when PubChem's chemical structures were mashed up with Wikiepia articles, using CAS numbers as the common link. The site design reflected this, with no clear organizing principle other than mashup. However, after the initial demonstration of the success of this approach, it became clear that Chempedia was strikingly similar in both form and function to the Merck Index. Perhaps this should be used as a clue in deriving a better organizing principle.
Wikipedia integration. The old Chempedia site didn't make it nearly as convenient as is should be to create or edit compound monographs. Because Chempedia serves as a chemically-aware front-end for Wikipedia, the easier it is to get to Wikipedia from Chempedia, the better.

What Changed?

During the process of trying to fix Chempedia's problems, it became clear that a major redesign was in order. This consisted of:

Creating a landing page oriented toward search. Using the Merck Index as a metaphor suggested that Chempedia's landing page should be designed around search, not browsing - as it was originally designed.
Emphasizing compound monographs, not compounds. Chempedia's central organizing principle is now the Compound Monograph. One way this is seen is in the new URL structure, which makes it very easy to see where a Chempedia link is about to take you. For example, consider the URL for benzene. Another way this can be seen is in the inclusion of Compound Monographs lacking a chemical structure.
Designing a streamlined menu system. The main menu system has been broken down into just three main categories: Search; Browse; and Create. These headings refer to actions on Compound Monographs, again in line with their importance as an organizing principle.
Promoting better integration with Wikipedia. After experimenting with a few implementation possibilities, it is now possible to edit Wikipedia articles directly from the Chempedia site, thanks to the use of inline frame. Once again, this capability is tied to the Compound Monograph, from which editing and updating links are accessible.
Striving for comprehensive Wikipedia coverage. Wikipedia had far more compound monographs than could be found on Chempedia, 6,411 of them, to be precise. Chempedia now contains all of them, regardless of whether a chemical structure can be found based on a CAS number in PubChem. This includes inorganics, organometallics, polymers, mixtures, and polypeptides.

Miles to Go Yet

Chempedia is far from being finished. For example, you'll notice many instances in which a Compound Monograph is truncated. This arises from difficulties in parsing Wikipedia's Wikitext format (more on this later).

Ultimately, the full text of each Wikipedia article will be present on Chempedia rather than just the first introductory paragraph. But it will take a significant amount of work to ensure that each article's Wikitext entry can be parsed faithfully.

Chempedia allows search by CAS number, PubChem CID and exact title. Full-text searching is not yet implemented, nor is autocomplete search, both of which would greatly enhance the usability of the service.

Exact structure searching is made possible by the ChemWriter editor in combination with SHA-1 hashed InChIs. Substructure search and query atom search will ultimately be added, but for an encyclopedia containing relatively few molecules, most of which having trivial names, this isn't yet seen as being critical.

You'll notice many Monographs on Chempedia that have no structure information. Behind the scenes, Chempedia uses the 350,000+ CAS numbers now contained in the PubChem database to associate a chemical structure with a Wikipedia article. In the future, these associations will be made by Chempedia and Wikipedia users, which will allow every Chempedia small-molecule Monograph to have a structure associated with it. (It will also create a rather large, publicly-curated, open database of CAS numbers linked to chemical structures, but that's a story for another time).

Your Feedback is Essential

Finally, many of the changes made in this iteration were the result of conversions with chemists and developers. If you see something on Chempedia that just doesn't work for you, please don't be shy about saying so. Feedback is an essential ingredient in making Chempedia the best service it can be.

The Economics of Free: Chris Anderson on Charlie Rose

Rich Apodaca — Sat, 10 May 2008 13:35:00 -0400

Anderson's comments on the Long Tail and social networks are especially on-target, and relevant to the sciences.

Building a Unique Chemistry Journal: Responses to Questions from Nature Chemistry

Rich Apodaca — Thu, 08 May 2008 14:48:00 -0400

Neil Withers of the soon-to-be-launched chemistry journal Nature Chemistry has asked for feedback to some questions about the best ways to display chemistry research papers on the Web. Here are some responses:

(1) HTML vs PDF: does anyone read the HTML articles? Do you read the PDF on-screen or print it out?

I've used PDFs both for offline archiving and sharing of especially important articles as well as one-off printing of a paper I'm interested in. I rarely read a paper on-screen if I can avoid it.

Typical workflow: (1) download PDF; (2) print it out; (3); let paper sit while I go do something in the lab that can't wait (or bring it with me); (4) put paper onto a rather large stack of papers just like it; (5) pull paper out of stack from time to time as needed; (6) (optional) file paper in an increasingly chaotic system of folders or recycle it.

This system is bad, and I cursed it weekly during my time as a research chemist. Most of my colleagues had similar experiences.

There are plenty of opportunities to address pain points with the Web. Some ideas:

Make it very easy to find papers on the Nature Chemistry site. If I know a paper is trivial to find, I'm less likely to print it out in the first place. Good search may not be enough (see question 3).
Make the online version as readable as it can be. Minimize fluff like menus, ads and general clutter. Maximize things that promote readability like reasonable column-widths, appropriate fonts, and attractive and readable images.
Add conveniences that make it easier to read the paper online such as hover-popups that display 2D chemical structures for trivial names and IUPAC nomenclature (see below).

Paper is portable but Web documents are alive. Both can be readable - for example, I never print out a blog posting to read it.

(2) Big vs little graphics: what does everyone else think about the tiny size of the graphics in ACS html articles?

Graphics should be sized appropriately. ACS HTML articles are a good example of failing to design the obvious. You'd never read a blog post that looked like those articles, so it's not surprising everyone prints out the PDF.

Another problem is over-wide columns. It's puzzling why journal publishers would ignore all of their hard-won design experience just because a document appears as a Web page. If the ACS used a narrower column width, the Web version would be more readable. For example, check out this article from Beilstein Journal of Organic Chemistry. The only thing I'd change is to make the font larger.

Both problems are correctable using the right software and techniques.

(3) Tagging/’semantic web’: what do you think about the toys on the RSC’s Project Prospect? What kind of things would you like to see tagged/linked to other content in Nature Chemistry? For instance, Steve would love to do something with named reactions.

If by tagging, you mean giving users the ability to tag articles like Flickr allows photos to be tagged, and for other users to make use of those tags while searching, I think it's long overdue and could be a game-changer. It would clearly play to the strength of the Web as a medium.

I must confess that I'm not a fan of the implementation of Project Prospect, although the idea has a lot going for it. There's too much bling and a lot of it fails on my Linux/Firefox 2 system.

The one Prospect feature well worth adapting would be the one that lets you get a 2D structure by clicking on a trivial name or IUPAC name. But there's a much better way to implement it:

Turn it on by default and get rid of the floating right-hand menu.
Make the structure appear, without clicking, by simply hovering the mouse over the trivial name or IUPAC nomenclature. Be sure the delay is set right so that it's not popping up unintentionally.

That's all there is to it. It needn't be complex, just usable.

Another possibility: harvest all of the 2D molecular structures appearing in articles over a given period of time to be displayed in a dense, hyperlinked graphical abstract format ideal for quick browsing.

(4) 3D molecular structures: do these help your understanding of a paper?

Rarely, and in many cases they just add clutter. For almost all small molecules, a properly laid-out and well-drawn 2D chemical structure is more useful. If a central point of discussion in a paper is a 3D structure, then that would be a good use of the technology.

(5) How useful to you are InChIs and SMILES?

Not very. Research chemists rarely care about this kind of technology. They'd much rather have a good-looking 2D chemical structure. InChIs and SMILES, if available, should be hidden away and only brought out when requested. A more basic problem is neither system will be able to encode all of the molecules your journal's authors are likely to discuss.

(6) Forward linking: the RSC and Elsevier/Science Direct offer this – do you use it? Would you use an RSS feed that alerted you to new citations of a particular paper.

It could be useful provided that clutter could be kept to a minimum. It's essentially a form of linkback (see below).

An RSS feed that published linkback activity might be useful, but many of the chemists I know still don't know what RSS is. On the other hand, a page (or email service) that could keep an interested reader updated on linkback activity on all of their papers of interest simultaneously could be very useful.

(7) Would you actually comment on papers if there was a comments box at the end?

Like Egon Willighagen, I'd probably use my blog to do it.

However, most chemists don't maintain blogs or other websites and for them I can see how the ability to post comments would be useful.

Both kinds of users could be accommodated through a combination of comments and linkbacks. Provided that a good spam filtration system were used, this two-pronged approach might be very useful to readers.

Blogs are just the tip of the iceberg, though. Web publication technologies are creating all kinds of opportunities for creating highly focused, constantly evolving, collaborative mini-reviews on special topics. Linkbacks would create value for both readers and authors of these mini-reviews as well as forward-thinking scientific publications that embrace them.

(8) We really like the Biochemical Society’s HTML article style (sample one here) – do you?

No. Frames makes that site very difficult to navigate.

It will be very interesting to see how Nature Publishing Group takes advantage of its opportunity to create something unique among chemistry publications. Asking the kinds of questions they're asking now, and doing so in the way they're doing it, shows they're at least on the right track.

1908 and All That: The Long Tail and Chemistry

Rich Apodaca — Wed, 07 May 2008 10:37:00 -0400

Quite a few American Chemical Society (ACS) divisions are celebrating their 100th anniversaries this year. While this fact may at first glance seem like just a piece of nerdy trivia, Rudy Baum, Editor-in-chief of C&E News decided to dig deeper. And what he found was the Long Tail of chemistry, alive and well - in 1908.

In his editorial, Baum describes how he looked for the causes of the sudden appearance of so many ACS divisions in 1908. At its core, he found a growing realization on the part of influential chemists at the time that ACS membership was becoming too diverse in their interests and areas of specialization:

Specialization in subdisciplines of chemistry was also much on ACS members' minds in these years. Some members felt strongly that subdivisions of some sort should be created in the society to provide a venue for chemists from these areas to meet separate from the society as a whole. It was noted that chemists were going off and forming their own specialized organizations in areas like electrochemistry, biological chemistry, and agricultural chemistry.

As early as 1903, ACS established a committee of five distinguished members to look into this issue, with Massachusetts Institute of Technology's Arthur A. Noyes as the chairman. (Throughout its history, ACS has responded to challenges by creating committees!) The committee reported to the ACS Council at its June 1, 1903, meeting, and strongly recommended that "Divisions of the Society be established representing different important branches of chemistry."

For those familiar with the work of Chris Anderson, what's being described is nothing other than the Long Tail:

The theory of the Long Tail is that our culture and economy is increasingly shifting away from a focus on a relatively small number of "hits" (mainstream products and markets) at the head of the demand curve and toward a huge number of niches in the tail. As the costs of production and distribution fall, especially online, there is now less need to lump products and consumers into one-size-fits-all containers. In an era without the constraints of physical shelf space and other bottlenecks of distribution, narrowly-targeted goods and services can be as economically attractive as mainstream fare.

How much money does it cost to set up a new ACS division? Probably not that much. How big is the field of chemistry? Vast. Put the two together, and you have a recipe for today's ACS. A recent Depth-First article described this phenomenon. And C&E News itself maintains a (static?) blog on the Long Tail as it applies to chemical employment.

What does any of this have to do with chemical informatics? Although it may be tempting to think of chemists as a homogeneous group sharing a great deal of experience and knowledge, the proliferation of ACS divisions suggests otherwise. It seems reasonable to think that successful chemical information systems would do well to take this into account in their design and implementation.

Building Chempedia: Indexing Wikipedia's 6,411 Compound Monographs

Rich Apodaca — Mon, 28 Apr 2008 18:22:00 -0400

The Merck Index is one of chemistry's most useful reference works. Organized like an encyclopedia, each entry, or "Compound Monograph," describes a single compound complete with chemical structure, CAS Number, IUPAC name, trivial names, physical properties, and leading primary literature references describing uses. Unlike other chemistry databases, the Merck Index focuses on only those compounds with important industrial, biological, medical, or technical applications.

What's Wrong with the Merck Index?

Wonderful product though it may be, the Merck Index has some limitations. For starters, online versions are not free. The disadvantages of this access model go well beyond a simple price barrier; it prevents the very thing the Web was designed to promote: linking. Another limitation is the time it takes for new versions to appear, which is typically measured in years. Still another limitation is in the cost of adding entries for niche compounds that may not be suitable for a general audience, a major barrier to exposing chemistry's long tail.

What's Chempedia?

If we wanted to create a free, online service that worked like the Merck Index but which took full advantage of today's powerful collaboration and information technology tools, how could we go about doing so?

This article, the first in a series, discusses Chempedia, a free, structure-oriented online encyclopedia of useful chemical compounds designed to answer this question.

Background

The following articles may be useful in understanding Chempedia's approach and underlying technology:

Where to Begin?

One of the first problems we'd face in building a free Web-based version of the Merck Index is where to get the compound monographs.

It turns out that Wikipedia (yes, Wikipedia) hosts a growing collection of compound monographs that, when viewed together, bear a striking resemblance to the Merck Index. And the effort is becoming increasingly organized with respect to content and data provenance.

Why not start here?

The Task at Hand

To get an idea of just how Wikipedia's collection of compound monographs compares to the Merck Index, it helps to know: (1) how to find Wikipedia compound monographs; and (2) the range of information available for each entry.

This tutorial will describe a simple method to index Wikipedia's compound monographs using nothing but free tools and data. Subsequent articles will discuss qualitative aspects of Wikipedia's compound monographs and the challenges involved in organizing them into a chemically-aware service.

Indexing Wikipedia's Compound Monographs

We can index Wikipedia compound monographs via a simple procedure.

Most compound monographs employ one of four precompiled Wikpedia templates: Chembox (deprecated); Chembox new; Drugbox; and Explosivebox. As an example of what these templates look like, see the right-hand box on Wikipedia's entry on modafinil. To index Wikipedia's compound monographs, all we need to do is find the titles of all articles using one of these four templates.

To get started, we'll need a local copy of Wikipedia. The complete set of all Wikipedia articles, as of March 12, 2008 can be downloaded here. This data dump is updated periodically, so you may have access to a more recent version.

The Wikipedia dump, which contains the full text of every article in Wikipedia, consists of a 3.5 GB file in BZip2 format. Fortunately, we won't need to inflate it to index its chemical content.

The following code will scan the raw Wikipedia dump and produce a list of all compound monograph titles:

title = ""
log = File.new 'monographs.txt', "w"

while((line = STDIN.gets))
  line.match /<title>(.*)<\/title>/

  if $1
    title = $1

    next
  end

  if line.match /\{\{(chembox|drugbox|explosivebox)/i
    unless title == "" || title.match(/:/)
      puts title
      log.puts title
      log.flush

      title = ""
    end
  end
end

log.close

Saving this code into a file called filter.rb, we can run it by piping the output of bzcat on the raw dump file:

$ bzcat <path_to_dump>/enwiki-20080312-pages-articles.xml.bz2 | ruby filter.rb

Alphabetizing the output file gives a complete listing of Wikipedia's compound monograph titles (all 6,411 of them), which for convenience can be downloaded here.

We can construct a URL to each Wikipedia compound monograph by prepending the title with http://wikipedia.org/wiki/. In other words, our program's output can be used both as a list of chemical names and as a hash of chemical names to Wikipedia URLs. And with the URL in hand, all kinds of interesting things can be done.

Limitations

Although easy to carry out, the procedure described here has some limitations:

Monographs added after March 12, 2008 are not visible.
Monographs that don't use the chembox, chembox new, drugbox, or explosivebox templates are not visible.
A very small number of articles erroneously use the chembox template, for example this one.

Chempedia Redesign

Currently, Chempedia doesn't include all 6,411 monographs but rather a subset created by a much less comprehensive indexing method. As part of a major redesign of the site, all Wikipedia compound monographs will be available on Chempedia, which should result in a much more useful service.

Conclusions

Wikipedia is fast becoming a major storehouse of chemical information with tantalizing potential for creating powerful new services for chemists. More to the point for cheminformatics, the entire Wikipedia dataset can be downloaded and reprocessed free of charge; Wikipedia is one of those rare cheminformatics datasets that is both free as in speech and free as in beer.

As this article has shown, some simple programming is all it takes to begin doing useful things with Wikipedia's chemical content. Future articles will discuss some of the possibilities.

Thinking of Founding a Science Startup? Look to What's Getting Cheaper

Rich Apodaca — Tue, 22 Apr 2008 17:59:00 -0400

Deepak Singh recently started an interesting discussion (and follow-up) about the need for organizations that help early-stage bioscience startups in the same way that YCombinator does in the Web space. But having just attended my second YC Startup School, I'm left with a new-found appreciation of the role startup economics plays in shaping not just the startup landscape, but the culture of entrepreneurship that goes with it.

There's a world of difference between the kinds of startups YCombinator is interested in and the kind of startup most chemists and biologists would be in a position to found. As told by Paul Graham of YCombinator, founding a Web startup is cheap, and that changes everything:

There's something interesting happening right now. Startups are undergoing the same transformation that technology does when it becomes cheaper.

It's a pattern we see over and over in technology. Initially there's some device that's very expensive and made in small quantities. Then someone discovers how to make them cheaply; many more get built; and as a result they can be used in new ways.

Computers are a familiar example. When I was a kid, computers were big, expensive machines built one at a time. Now they're a commodity. Now we can stick computers in everything.

This pattern is very old. Most of the turning points in economic history are instances of it. It happened to steel in the 1850s, and to power in the 1780s. It happened to cloth manufacture in the thirteenth century, generating the wealth that later brought about the Renaissance. Agriculture itself was an instance of this pattern.

Now as well as being produced by startups, this pattern is happening to startups. It's so cheap to start web startups that orders of magnitudes more will be started. If the pattern holds true, that should cause dramatic changes.

Contrast the options available for a computer science student with those of a biology or chemistry student.

The computer science student enjoys access to state-of-the-art tools that have been commoditized to the point of being either completely free or very close to it: hardware; hosting; operating systems; programming languages; development frameworks; source code management tools; and, increasingly Web services. More than one multimillion-dollar Web startup has been founded with nothing more than a laptop, a dorm room, some macaroni, a few friends, and a good idea or two.

The life- or physical science student is faced with quite a different reality. Everything needed in getting started costs money - lots of money: lab space; instruments; consumables; a patent lawyer or two; and regulatory approval, both for day-to-day operations and possibly for the product to be sold.

Then there's the problem of time to market. A Web startup can go from nothing to finished product over a summer vacation. Depending on the product being sold, a science startup may take ten years or more to do the same.

This glacial product development cycle leaves the science startup with almost no room for error. In contrast, the Web startup is in a position to start offering a significantly flawed product early on and then iterate until it's perfect.

These contrasting situations go a long way to explaining why bioscience startups tend to be founded by thirty- or fourtysomethings and Web startups can be and are founded by teenagers.

With ready access to cheap means of production, Web startups enjoy many advantages that science startups can only dream of. For one thing, a product can actually be developed before approaching outside investors even becomes necessary. It's even possible to build a profitable Web startup purely from the profits created by selling the finished product.

The bio or chemistry startup, on the other hand, will tend to be dependent to varying degrees on outside investors from the beginning. In some cases, the University hosting a science startup's early-phase research will play the role of outside investor, much to the founders' disadvantage.

What do you get when you combine a need for large sums of money up-front with a need for almost perfect execution? A recipe for failing in business more frequently than anybody else.

We might expect this situation to change if the cost of founding a startup in the life- or physical sciences dropped significantly. It may take a little imagination to see this as a possibility right now. But the process of new markets forming when technolgy becomes radically cheaper is a fundamental feature of captitalist societies that has played out time and again over the last several hundred years.

If a transformation is in store for the economics of biotech and chemistry startups, what could trigger it?

Image Credit: mathoov

Building a Technology Company the Old-Fashioned Way

Rich Apodaca — Mon, 21 Apr 2008 08:44:00 -0400

What's the secret to making money on the Web? David Heinemeier Hansson's talk at Startup School 2008 offers a much-needed, but all too easy to ignore, dose of reality. Although some of his comments aren't nearly as funny out of context, this presentation is well worth the time for anyone serious about building a solid technology business.

Is reCAPTCHA Trying to Tell Me Something?

Rich Apodaca — Fri, 18 Apr 2008 10:59:00 -0400

Casual Saturdays: Periodicity is Just a Theory

Rich Apodaca — Sat, 29 Mar 2008 09:16:00 -0400

Credit: reDiscovery Institute