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"Farming" Amoebas Discovered 49

Posted by samzenpus from the rise-of-amoeba-agriculture dept.
Researchers from Rice University have found a type of amoeba that practices a sort of "primitive farming behavior." When their bacteria food become scarce, the Dictyostelium discoideum will group together and form a "fruiting body" that will disperse bacteria spores to a new area. From the article: "The behavior falls short of the kind of 'farming' that more advanced animals do; ants, for example, nurture a single fungus species that no longer exists in the wild. But the idea that an amoeba that spends much of its life as a single-celled organism could hold short of consuming a food supply before decamping is an astonishing one. More than just a snack for the journey of dispersal, the idea is that the bacteria that travel with the spores can 'seed' a new bacterial colony, and thus a food source in case the new locale should be lacking in bacteria." It's good to know that even a single celled creature is not immune to the pull of Farmville.
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Survey Shows That Fox News Makes You Less Informed 1352

Posted by samzenpus from the fair-balanced-and-simple dept.
A survey of American voters by World Public Opinion shows that Fox News viewers are significantly more misinformed than consumers of news from other sources. One of the most interesting questions was about President Obama's birthplace. 63 percent of Fox viewers believe Obama was not born in the US (or that it is unclear). In 2003 a similar study about the Iraq war showed that Fox viewers were once again less knowledgeable on the subject than average. Let the flame war begin!
Security

TSA Pats Down 3-Year-Old 1135

Posted by samzenpus from the security-theater dept.
3-year-old Mandy Simon started crying when her teddy bear had to go through the X-ray machine at airport security in Chattanooga, Tenn. She was so upset that she refused to go calmly through the metal detector, setting it off twice. Agents then informed her parents that she "must be hand-searched." The subsequent TSA employee pat down of the screaming child was captured by her father, who happens to be a reporter, on his cell phone. The video have left some questioning why better procedures for children aren't in place. I, for one, feel much safer knowing the TSA is protecting us from impressionable minds warped by too much Dora the Explorer.
Censorship

Google Stops Ads For "Cougar" Sites 319

Posted by samzenpus from the here's-to-you-mrs-robinson dept.
teh31337one writes "Google is refusing to advertise CougarLife, a dating site for mature women looking for younger men. However, they continue to accept sites for mature men seeking young women. According to the New York Times, CougarLife.com had been paying Google $100,000 a month since October. The Mountain View company has now cancelled the contract, saying that the dating site is 'nonfamily safe.'"
Book Reviews

Submission + - Metaprogramming Ruby

Submitted by scottl
scottl writes: Metaprogramming Ruby is the first book to give an in-depth and readable explanation of how dynamic programming works in Ruby. It is both readable and accurate and will be a valuable resource to intermediate and probably advanced Ruby programmers for some time to come.

Metaprogramming Ruby is not a book for programmers new to Ruby, but would make an excellent follow on book to either Programming Ruby by Dave Thomas, Chad Fowler, and Andy Hunt or The Ruby Way by Hal Fulton. Both of the above books have chapters on or at least mention metaprogramming, but this is the first full length exposition of it. The book itself is broken into two sections and four appendices. In the first section, you (the reader) is paired with a more experienced programmer for a week, a chapter for each day, and as the week progresses you cover different topics in metaprogramming after being given tasks by your boss. The second section has two chapters on the design and implementation of ActiveRecord from Rails as well as a chapter on safe metaprogramming. Finally, there are three very useful appendices and a bibliography. One other note is that the book has the concept of “spells”. Each concept as it is discussed in the book will have a spell associated with it. There will be a note in the sidebar with the name of the spell and the third appendix has the spells listed in alphabetical order, a short example of the spell, and a page number linking back to the extended discussion of the spell.

The first chapters are an informal introduction to metaprogramming where the reader, just starting a new job, is paired with Bill, an experienced developer, for a week. Each day is a chapter and each chapter covers a specific topic. The topics, as might be expected, increase in complexity as the week goes on. This more informal style actually works quite well. I had expected to be a bit irritated with the “schtick”, but it turns out that Perrotta does not use it to excess. The topics covered here are Monday: The Object Model, Tuesday: Methods, Wednesday: Blocks, Thursday: Class Definitions, and Friday: Code That Writes Code.

Chapter 1 on Monday starts out with you meeting Bill, your experienced pair programmer, on a Monday morning and then goes straight into the Ruby object model. It discusses reopening classes to add additional methods including predefined Ruby classes such as String. It follows up with Monkey Patching (opening an existing class and redefining an existing method) and the pitfalls therein.

In Chapter 2, methods are examined. Perrotta goes over a problem with duplicated code and how to reduce this code by generating and calling code dynamically. He then moves to showing the same example using method_missing(), followed by adding a change to respond_to? to make sure the methods show up.

Wednesday's topic in Chapter 3 covers blocks, lambdas, and procs all of which are really just “callable objects”. The chapter starts with a review of blocks. This is followed by a discussion of scopes and how to carry variables through scopes using blocks as closures. Perratto shows how to use instance_eval() to receive blocks and then use them to manipulate scopes. Next, converting blocks into “callable objects”, lambdas and Procs, and then calling them later is covered. Finally, there's a short introduction to domain specific languages (DSL) using the the techniques from this chapter.

Chapter 4 or Thursday covers class definitions. A discussion of self and the current class open the chapter. There's also a section on singleton methods and eigenclasses. There are class instance variables, variables that belong to the class and not to a particular object. Examples of class macros, such as attr_reader, attr_writer, and attr_accessor, and how to write them are shown. Finally he covers around aliases where method names can be renamed and then redefined but the original is still available.

The final day of the week, Friday, Chapter 5, goes deep into Ruby metaprogramming with code that writes code. In this chapter, Perrotta shows how to implement an “attr_checked” attribute in a few different ways starting with a kernel method using eval and moving on to passing the validation attributes in a block. Then this gets moved to a class macro (from Chapter 4), and finally moving on to using a module with hooks. This last is a pattern that's seen in many Ruby projects including Rails and two I'm familiar with, Sequel and Ramaze.

The second section, Metaprogramming in Rails, consists of two chapters on ActiveRecord and a final chapter on metaprogramming safely. In the first two chapters, Perrotta takes a tour through
ActiveRecord, the Rails object relational mapper (ORM) and shows how ActiveRecord uses the tips and techniques from the previous chapters. The final chapter on safe metaprogramming discusses how to test metaprogramming and working around and with to make sure that monkey patching doesn't cause problems.

Finally, there are three appendices. The first shows common Ruby idioms that are seen pretty much in all Ruby code. They provide a good review, but I'm not sure how useful they really are for the audience that this book is aimed at. The second appendix is one DSLs. This is also a nice to have, but there's probably not enough to let you program a DSL if you don't have additional help from somewhere. The final appendix really is almost worth the price of the book. It contains a list of metaprogramming “spells”. Each of the spells contains a short programming example as well as the page number with the longer explanation. This is incredibly useful when looking at code from any of the major frameworks (some mentioned above) and you don't understand a piece of it. Just by scanning through the spells you can often find a simple version of what you're looking at and then read a longer explanation.

All in all, this is one of the better, more readable programming books that I've read in a long while. Perrotta keeps it to around 250 pages including the appendices and it's packed full of useful information. As I noted above, this book is highly recommended as a second Ruby book. The presentation of metaprogramming is both enjoyable and useful and the book itself is well written.
Graphics

Disney Releases 3D Texture Mapper Source Code 83

Posted by timothy from the nice-of-them dept.
dsavi writes "Ptex, Walt Disney Animation Studio's cutting-edge 3D texture mapping library which was first used on nearly every surface in the 2008 animated feature Bolt, was released under the BSD license on Friday. Quoting the announcement on monophyl.com: 'We expect to follow Ptex with other open source projects that we hope the community will find beneficial. We will soon be launching a new Walt Disney Animation Studios Technology page under disneyanimation.com. It will include links to our open source projects as will as a library of recent publications.' This looks good for open source 3D graphics."

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