Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror

Comment: Basic intro to the planarian flatworm (Score 2) 106

by nohelix (#39186443) Attached to: Flatworms Defy Aging Through Cell Division Tricks
The planarian has come up several time here on /. and I thought that some people might like a quick intro these guys.

The flatworm used in this study is the planarian S. mediterranea, a free living (i.e. non-parasitic) flatworm. They have a distinct head and tail. They have non-lensed eyes capable of detecting the direction and strength of light allowing them to move away from it. Finally, they have a bi-lobed cephalic ganglia (rudimentary brain) and a rudimentary CNS. A similar species of planarians (dorotocephala) is frequently seen in high school science class.

There are 2 varieties of this species - one reproduces asexually while the other reproduces sexually. Both varieties are capable of complete regeneration (i.e. a full worm from almost any fragment) when cut. In both cases, the only dividing cells in the worms are stem cells called neoblasts.

Fun Fact: Thomas Hunt Morgan did many of the initial experiments on planarians.

-----
Standard disclaimer: I work in a lab that uses these animal.

Comment: Re:Finally... (Score 3, Informative) 410

by nohelix (#36264118) Attached to: Steve Ballmer's Head On the Block?
Additionally, Bill and Melinda Gates are the second most-generous philanthropists in America (as of 2007 by Bloomberg ratings). He has been successfully married for 17 years and has 3 children. He is an honorary Knight. Jobs has an illegitimate child that he caused to be raised on welfare when he denied (then later acknowledged) paternity. He allowed his personal feelings to influence his business decisions when he banned all books from a publisher from Apple stores because the publisher had published an unauthorized biography of him. While his wife is now focused on non-profit and charity work, he is not noted to sit on any of the boards she serves on. I make no claim about their companies, but their lives outside their jobs are as different as night and day.

Comment: Re:Video Gaming and Video Gaming (Score 2) 99

by nohelix (#36192548) Attached to: Video Game Playing Increases Food Intake In Teens
They did blood tests to monitor hormones and no increase in appetite inducing hormones was seen. Additionally participants didn't report being hungrier. This would imply that the brain is not actually signalling for higher caloric intake. However they comment that they did not check for satiation signals or stress-reward signals. They suggest that the 'mental stress' caused by playing the games is the cause. This stress should be the same regardless of the type of game played. They have seen similar increases in other studies with mentally strenuous activities such as arithmetic.

Comment: Re:Is Facebook a viable long term business model ? (Score 2) 295

by nohelix (#34793994) Attached to: Facebook's Revenues Leaked
Right now it has the pleasure of being the place for the young and the cool. In another 5 or 10 years when all your parents are on Facebook, teenagers will find a new 'cool' online hangout. No teen wants to hangout with their parent and so it will change as it really beings bridging the generational gaps. Its just like real life - 50 years ago it was 'Soda Fountains', 30 years ago it was Bowling alleys, 15 years ago it was the Arcade, 5 years ago it was Myspace, and now it's Facebook.

Comment: Re:Cute application, but why? (Score 3, Informative) 131

by nohelix (#32266472) Attached to: Marine Mammals Used To Fight Terrorism

This is a truly novel approach, but what kind of sophisticated aqua-terrorists are we genuinely preparing to encounter?

This is not a novel approach.
Both the US and Russian governments have been training and using marine mammals (wikipedia) as well as other animals (wikipedia) to help with military tasks. Dolphins and sea lines have been in training and use in the Gulf Wars. Perhaps the funniest example of military animals is the dogs that the failed Russian anti-tank dogs (wikipeida) that due to their training attacked Russian instead of enemy tanks. Its worth noting that this was again unsuccessfully attempted by Iraqi insurgents in 2005.

Comment: Re:hmmph, sensational (Score 2, Informative) 355

by nohelix (#31986322) Attached to: How To Grow a Head
While you are mostly correct about this, even in planarians, head regeneration requires a suite of genes. By cutting the animal, those genes are activated and then the RNAi is used to alter their expression patterns. It is not as simple as one gene makes the whole head. Its that this gene is one of several including the Wnt/beta-catenin genes that work in concert to properly pattern the head.

To get the multiple head phenotype, the animal must be cut and in its 'regeneration' expression profile - not its homeostasis expression patterns. Nou-darke causes ectopic (extra) brain formation (in a different species of planarians) and brain region extension (in both species) even in non-regenerating planarians, which is not how this gene (Smed-prep) works.

Note that S. mediterranea has two strains, a sexual (cross-fertilizing hermaphrodites) and an asexual strain (that reproduces by fissioning). This means that the animals maintain adult stem cells that can regenerate an entire planarian (and are the only dividing cells in the animal). This gene is not expressed in those stem cells, but it certainly interacts with them in the development of the ectopic heads.
Disclaimer: I work in a S. mediterranea research lab

Comment: Re:And for further reading (Score 4, Insightful) 355

by nohelix (#31984802) Attached to: How To Grow a Head
This is very true. Just look at Nobel [Wikipedia]. When designed nitroglycerin, he was trying to make a safer explosive for miners. Instead he made a tool of war and was horrified by it. It was not his morality nor his invention that was flawed. It was the people who used it. I would think by now that our society had moved past the base point of science is evil and technology is amoral. That cell phone in your pocket could be used to make a bomb threat or call an ambulance for the guy having a heart attack. As for this research, it is quite a ways off from any useful/practical applications. But people hope that when it does come to fruition, it will be for things first like severe brain damage cause by an accident, a blood clot or other damage. And while yes, planarians have a cephalic ganglia (brain) and a complex nervous system for being a simple invertebrate, it is vastly less complex than even a mouse brain. As a case in point, their "eyes" are a photoreceptor not a lens, so while they can see and react to light, they do not have the capability to distinguish shapes. Disclaimer: I work in a research lab that uses S. mediterranea, the flatworm used in this paper.

Comment: Re:And how does it differ ? (Score 5, Informative) 209

by EvanED (#30954726) Attached to: x86 Assembler JWASM Hits Stable Release

And how does its syntax differs from NASM and AT&T ?

Intel syntax doesn't feel like it was designed by a sadist.

More seriously, this site link covers some differences. Among the things I like much more about Intel syntax: there's no need to add a ton of visual noise with what-should-be-extraneous $ and % symbols, and things like memory indirection is much easier to learn. Compare "[ebx+ecx*4h-20h]" to "-0x20(%ebx,%ecx,0x4)"; the former almost tells you what it does even if you're not at all familiar with the syntax, the latter definitely doesn't.

The main benefit that AT&T syntax has is that they "hungarian notation" their instructions: movb works on 1 byte, movw on 2 bytes, movl on 4. Most of the time this is extra visual noise (I don't need the 'l' to tell me that 'mov eax, ebx' works on 4 bytes), but it does make memory dereferences more concise. With Intel syntax you'll get a lot of 'dword ptr' stuff lying around to tell how much should be brought in from memory.

Comment: Re:Manufacturing and distribution (Score 1) 531

by tepples (#30954634) Attached to: Has Apple Created the Perfect Board Game Platform?

If you have 3 or 4 different game groups are you going to buy enough iPhones that each person can have one?

I think the idea is that the game publisher puts out a "controller" for Android and a "controller" for iPod Touch/iPhone, and you get whatever "controller" matches the handsets your players already have.

Comment: Re:Fuck Google (Score 1) 127

by syousef (#30954242) Attached to: FCC Probes Google and T-Mobile For Double-Whammy Fees

You have quite plainly demonstrated that you are a douche, but not why I must be a liar.

Here's the thing, I'm not getting personal when I call you a liar. I simply do not believe that you could possibly have read every document. You're just name calling when you call me a douche. I don't suppose you'll see the difference but that's your problem.

I can't think of any software I use that came with an EULA, although I usually read the license it comes with if it is new to me. For example, the GPL took me 3/4 of an hour to read 8 years ago.

Ah I see. So have you ever used anything that's licensed as GPL 3? What about a BSD license? Has any software you've used varied from the GPL? Are you fucking seriously telling me you read and digested the entire GPL in 3/4 of an hour, with all it's implications, when there are grey areas around it? (Why do you think GPL 3 was created?)

But the rest of your rant makes no sense.

Perhaps if you refuse to try to understand it.

Where did you get the idea I was for abolishing the protections that exist? How does suggesting that people be responsible for what they sign mean that I believe companies are free to write whatever conditions they like? What kind of logic are you using?

The same logic that hauls Google and T-Mobile up to answer for their inclusion of terms in the contract that are not reasonable and allow them to double dip and overcharge for breaking a contract. Those same protections that make it illegal and unenforceable to enslave your family in the fine print of a contract are the ones that come into play for this story. I don't know what is so difficult for you to understand.

Whatever was going through your mind, the fact is that in THIS case we are talking about a straight up contract - there was no adhesion or exploitation.

You don't think that charging more for a device under a break of contract than for a brand new device up front is exploitative? And you call me a douche? Get a grip!

Comment: Re:Dear FSF (Score 1) 1634

by quadelirus (#30935884) Attached to: iPad Is a "Huge Step Backward"
"bullshit publicity"

I'm sure the reality distortion field will have waned in 60 days and sales will be driven by the actual in-hand experience people have. If they like it, they'll buy it, otherwise they won't. Personally I'm not passing judgement until I get to play with one. I can see really great use-cases for it, especially in areas that I've been annoyed with using either my laptop or smart phone for, but will it really fill the niche? That remains to be seen.

Sigmund Freud is alleged to have said that in the last analysis the entire field of psychology may reduce to biological electrochemistry.

Working...