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Comment As a biology professor (Score 2) 145

Most students who take an anatomy class at the level that requires animal dissection fall into two categories: those who are interested in an allied health profession (e.g., nursing, physical therapy) and those who are either interested in becoming professional biologists or medical doctors. I think you could make a pretty good case that in both cases, real dissections are an essential part of the students' training. Your average college student is not masochistic enough to take what is typically a course much tougher than a garden variety general education class. I don't know how the education system works in India, but I think the vast majority of biology departments in the US would not be willing to use models exclusive of real dissection. That being said, we do use models to supplement instruction, but these are physical models, not computer-based. Unless 3D displays become radically better and give tactile feedback, I don't see computer dissecting simulations displacing physical models either.

Comment my experience (Score 1) 315

my new iPhone 4S out of the box had a fast draining battery. After messing with it in a completely non-scientific and non-systematic way and switching off some services (e.g., Ping) battery life is "normal" now. So it probably is a software issue.

Comment Portal and Portal 2 (Score 1) 480

my 10 year old LOVES Portal, and Portal 2 Co-op mode is loads of fun. It's not quite an adventure game in the pure sense, but the last level of Portal really captured her imagination, especially with the escape into the hidden areas of Aperture Labs. Portal 2 Co-op mode on an XBox is really good, because it's split screen, which makes it very easy to help out when the other player gets stuck.

Comment Re:Some People (Score 0) 728

You, sir, are an idiot. Let's say someone exploits this and blows up a flight somewhere. Or, they manage to hijack the plane and fly it into some building (the how is irrelevant). I don't see any of the people killed by the collateral damage opting out of getting killed.

Comment What about ATP? (Score 1) 405

Phosphorus (or more precisely, phosphate) is used to form the covalent linkages between nucleotide bases in DNA and RNA. You could, in theory, retain the Watson-Crick basepairing of G, A, T, and C while replacing phosphate with something else such as arsenic. That is to say, the nucleotide bases are the bits of information, whereas the phosphate just holds it all together. To use a computer analogy, data is data, whether you store it on a hard drive or a flash drive.

What intrigues me more, is what about ATP? Adenosine triphosphate is not only used for making RNA, but it's also the universal common energy currency for almost all enzymes in all known organisms that catalyze endothermic reactions. If phosphate is not used in this arsenic-based organism, do they still use ATP as an energy source, and if not, what does it use and what kinds of adaptations does it enzymes have to accomodate this?

Comment RNA editing has been known for a long time (Score 1) 196

That mRNAs are edited post-transcriptionally has been known for some time now. In mammals, RNA modifying enzymes will act on specific mRNAs to alter their base structures, thereby changing their amino acid encoding. (too tired right now to provide a link, but this happens for mRNAs coding for AMPA-class glutamate-gated ion channels). It's not so much that it happens per se that is amazing; its that it happens at this large scale.

Much of this stuff is based on nex-gen high throughput sequencing technology, which has emerged just in the past 3-4 years or so. Very cool stuff.

Comment ebooks (and e-music) suck (Score 1) 437

why would I want to buy books and music that is tied to either a particular hardware platform and/or DRM scheme, at or above (or even near) cost of the physical media? Whenever possible I buy CDs or dead tree edition books. Occasionally I have bought DRM-free tracks from Amazon (I don't want to buy iTunes tracks because even though you can get DRM-free stuff from there it's inconvenient to move things between different devices), but overall I prefer physical media, which I can chose to sell later in the second-hand market if I so choose.

Its the same deal with e-textbooks. I teach university-level biology, and when the publisher is asking $100 for the e-book and $120 for the hardcopy, how can I recommend the ebook in good faith, especially when the publisher even outsources their DRM technology?

Comment blame it partly on the procurement process (Score 2, Insightful) 367

I don't know about other states, but in CA once money is earmarked for construction (many times it's so-called "one-time" money, or money that came from a one time windfall), one is prohibited from using it for any other purpose. For instance, at my daughter's school district, the new annex just completed this year at the district office has leather couches, mahoghany accent tables, and marble floors in their reception area. All the money for the construction of this annex was earmarked years ago, when the economy was still "strong". Despite the fact that the actual monetary needs of the district are elsewhere (teachers anyone?), they cannot use the money for anything else, even though it would have made much more sense to go with cheaper materials and use the surplus from construction to fund instruction.

Comment the summary is wrong (Score 4, Informative) 125

On a research grade light microscope, the maximum magnification one can get without loss of resolution is roughly 1500x - 1600x, not 400x as the summary suggests. Also, resolution of the image has nothing to do with magnification; the numerical aperture (N.A.) of the objective lens determines the resolution.

Comment Re:Where are we with Viral Immortality? (Score 2, Insightful) 187

no, engineered viruses are nowhere near that advanced. Most viruses are limited by payload; there is a limit to how much DNA (or RNA) you can engineer into a viral particle. (not unlike a BIOS virus I suppose). Also, the viruses that are able to modify the host genome do so at random locations, so it is hard to precisely control where you want a particular modification to occur. And, the virus only modifies a very small portion of the host genome. Finally, most viruses are highly picky as to what kinds of cells they will infect. For instance, HIV will only target helper T cells in the immune system. Engineering HIV to, for instance, infect cytotoxic T cells (another type of white blood cell that is similar but distinct) will never work, because as far as HIV is concerned a cytotoxic T cell is no different than a kidney cell (that is, it's not a helper T cell).

Comment Re:old news (Score 1) 187

I agree that the article makes it sound recent and I got misled too before reading TFA.
But can you explain why you differentiate between cell aging and human aging? Isn't human aging a consequence of cell aging?

cell aging is different than organism aging. Cells, by and large, are cheap to produce and are expendable. You produce cells via binary cell division; one cell becomes two new cells. However, most cell lineages can divide only a finite number of times. When cells from a lineage have undergone a certain number of divisions, they lose the ability to divide further. This is what is generally meant by "aged cells". Of course, each cell has a limited useful lifespan as well. Some cells (red blood cells) only last a few months, whereas others (neurons) last a lifetime. But whereas it is easy to replace a RBC (because of stem cells that do not have a limited number of cell divisions), it is somewhat harder to replace a neuron.

The number of times a cell can divide is limited by how long telomeres are. Each time a cell divides, its telomeres get shorter. The cell has mechanisms in place that measures telomere length. Once they are below a certain threshold, cell division stops. This is because (for reasons too detailed to get into here) sufficiently long telomeres are essential for replication of chromosome ends. Without such long telomeres, chromosome ends would fail to replicate. Normal cells do not express active telomerase, the enzyme needed to maintain telomere length during DNA replication. Stem cells and cancer cells have active telomerase.

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