CharonY

As the title says, a paper just came out in which the use of lures by alligators has been reported. V. Dinets, J.C. Brueggen & J.D. Brueggen , Ethology Ecology & Evolution (2013): Crocodilians use tools for hunting, Ethology Ecology & Evolution, DOI: 10.1080/03949370.2013.858276 The abstract: In a photo within the article an alligator was balancing sticks and similar nestbuilding materials on its head. Now they need to learn how to use beer as a lure...

No, Tm is length dependent . The more nucleotides are involved, the more energy is needed. The way to look at it is that it is a stochastic process and with increasing temperature the likelihood of a bond being dissolved (or formed) increases (decreases). However, for more bonds (i.e. bases) you need more successive events. It gets a bit more complicated due to the fact that neighboring interactions factor in as well. I.e. if a bond is present it stabilizes the neighboring bond.

That is not enough information as it would depend on the type of gel electrophoresis being conducted. Since we also do not provide direct answers it would be ideal if you provided some more context and tell us about your initial thoughts.

It is necessarily so, as biological entities are highly complex and so are their properties. A simple description for complex properties are necessarily imprecise. The terms life and death are superficially precise, but if looked deeper into that it is clear that they are not (again, because it is used as a description for biological, complex entities). This does actually go further as the way we describe things so that we can understand them is obviously highly context dependent (see Arete's example). I used the term "fail" to describe cell death, but of course in the context of programmed cell death it is not a failure, but precisely the way things work so that an organism can live (whereas the cell dies). In truth, biological processes are are just highly physical processes, and we give them specific terms in order to better describe them within specific contexts. I should stress: the terminology is only vague if you try to apply them in an universal context. Within certain research areas the terms are usually used in a very precise manner. Apoptosis for example is a highly structured form of cell death. Other or similar parameters can be used depending on whether you are looking at cells from a cytotoxicity, developmental or cell physiological viewpoint.

Generally one would consider a cell dead once integrity has been compromised to an extent that it cannot resume regular cellular functions. There is usually not a single element but a strong indicator is membrane integrity. If that fails, energy generation stops and there is no real way to recover from there. But there are usually many factors that may lead to this, including complex apoptosis programs that result in a controlled cell death. Again, there is no singular magic spark that determines whether a cell is alive or not, but many elements that fail, sometimes in a coordinated manner.

I have to agree with Ophiolite. Nonewithstanding any intentions may may have had, life in itself is a tricky and somewhat arbitrary concept. That does not in any way invalidate concepts of evolution or any approaches one may have developed towards understanding abiogenesis (quite the opposite I may argue). As I has been pointed out by Ophiolite, me and many others the definition of live is a concept that we created for practical purposes but does not necessarily reflect reality on all complexity levels. For example, with a very simplified view you could argue that cells perform homeostatic actions, and to some extent they do. For many approaches it is useful to assume a certain type of steady-state, too. But obviously things change almost on a constant basis if looked closely enough (just think in terms of cell cycles etc.). One should get used to the fact that certain definitions are matters of convenience to be able to frame specific questions. Edit: Cross-posted with Arete, but he provided a beautiful example why the definitions are in flux. To give a counter-view, coming from a more systems-oriented view that does not specialize on evolutionary processesI would consider viruses more to be mobile genetic elements with no distinct metabolic activities. Both views are valid for the respective questions being investigated.

That is true. Practical courses are much more rigorously structured. Most are not geared or useful for data generation, though. From the OP I had the impression that it was a bit more like volunteer work or undergrad research. I could be wrong, of course.

In my experience it works better if they have a deliverable that they have to present after a give amount of time (analyze X samples with Y amount of error and present at the end of the week or suchalike). Having fixed hours can result in people coming in and just wasting time (this depends on how the lab is organized, though). That being said, it is useful to provide guidelines i.e. each analysis takes that amount of time so you likely need to be here at least three times a week and put in 8h each day or you are not going to make it (as an example).

How are these compounds inorganic? But simply put, trying to make a plant (or even a cell line) to synthesize a specific compound is very complex, certainly not inexpensive and requires the introduction of new metabolic pathways that do not screw up the existing ones. Metabolic engineering is a complete research field on its own and relies on massive amounts of trial and errors. And even if successful (which generally takes years of blood sweat and grad student tears) the extraction of a pure compound is often not trivial either (though usually much easier). Honestly, there is little chance for individuals without a fully equipped lab and a decent sized work group to succeed in this endeavor.

One sticky point for me is that I have not yet seen many studies that demonstrate actual rather than potential benefits of GMO crops. I think it would require some more studies to see whether it is really going to be a solution to problems or not. Whether the public is going to accept is is more a public policy and education issue than a biological one.

One thing that I forgot to mention is the worry (that is shared with traditional agriculture) that massive replacement of indigenous crops may further reduce biodiversity of our food base. Especially if one or two supercrops become the main staple.

The regulation of DNA expression is done to a large extend by proteins, often in conjunction with other metabolites that may act as signal molecules. Cells that are not differentiated yet experience whatever signal is around and together with whatever is already in the cell eventually programs might be initiated that result in cell differentiation (to oversimplify things quite a bit). Already differentiated cells have a different composition of biomolecules and these will control what part of the DNA is being transcribed. This is actually quite well known and falls under the broader context of gene regulation. I take you mean that nobody specifically explained it to you? There is quite a bit of detail about how this happens and one common text book example of gene regulation via a metabolite is the lac operon (I am certain that wiki has it, too). There are many, many, many more examples and together they are a part of the reason why different cells express different proteins.

I am not sure what you really mean. You cannot use a virus by itself to overexpress a protein. If your question is why one did not use a viral vector to introduce it into a insect cell lines to produce insulin there, then the answer is that large scale protein production is easier in bacterial cells, if they can be produced well enough.

It depends on the GMO and on region. In my opinion the largest need for improved crops is found in third world countries. As such a GMO would ideally be more productive, cheap, and ideally provide more nutrition. At the same time, they should minimize harm in the environment. Chances are that, if properly implemented there is e.g. a chance to reduce pesticide use, which has the chance to be cheaper (as one would not need to buy certain pesticides) and may have less ecological impact than actual pesticide use (though some more studies would be beneficial). My main skepticism is whether theses crops would be made available to those that are in need and what type of dependencies this may create for the farmers. For example, the use of Monsanto crops is rather strictly licensed, and you cannot simply use seeds from your own crops to become self-sustainable. This may result in an unhealthy dependency on certain corporations. In addition, I am not sure by how much these GMOs would effectively reduce pesticide control, often times there is a mix that is being used and in some cases the GMO is just resistant against a specific herbicide, which is then used on the field. I think in the end I would like to see a larger number of studies that do some current cost/benefit calculations before I make up my mind.

That is a quite common issue and I wished that there was an universal solution to it (oh, how I wish). It will depend quite a lot on the individual, but I found that over the years in university a certain type of economic thinking becomes prevalent in students. I.e. do the least amount possible to get through whatever you have to, so that you invest your time that is more interesting/fun to you. At this point in live many do not have developed a proper work ethics in which they see assignment as a job that has to be done well. It gets worse when things have to be repeated. In their minds they already did the assignment and do not understand why the have to repeat it. It takes quite a bit of an effort to change the attitude from student to worker (and sometimes it only happens late in their PhD). The alternative is, as has been suggested, to utilize the whole work more in an assignment/class based work. Instead of going the scientist route (i.e. being excited by the work itself) one has to break down the work into smaller (and gradable) assignments. Truth been told, I found that the majority of students are happier with simple, even mindless assignments for which they get good grades as compared to solving interesting questions. Maybe 2% are getting interested or show up with a good work ethics (often older students, with work experience, military experience, or, somewhat strangely, perhaps, foreigners) Note that my posts are a very bad source to learn English as I ramble and generally only make a passing acquaintance with orthography, grammar or logic, when I post.

The X that you see are two identical chromatids that are still attached to each other. The chromatids are separated during cell division and then are resynthesized during the S-phase of the cell cycle. A pair of chromosomes would either be two separate chromatids or two "X" (after DNA duplication). And no they are generally not neatly condensed nor lined up nicely. This is only the case shortly before cell divisoin. Most of the time (i.e. when the cell is doing things other than preparing for replicating) the nucleus looks a bit like a mess. The differences are within specific areas on the chromosomes, or "loci". I.e. at a given base position with the DNA some may have A whereas others a G for example. This is what is generally called a single nucleotide polymorphism or SNP.

http://xkcd.com/1217/

Depends on how theoretically you want to be, The thing is that it is rare that a single gene controls a given phenotype. The latter is the result of thousands of proteins and metabolites interacting with each other (and the environment). Of course if we knew everything we may be able to create models. At this point it is pure science fiction, however. Also only at that point do we really know how much computational power we really need. Whether we will ever achieve this information is one of the big questions in biology,

We do not know sufficiently about how the biomolecules interact to create to create certain phenotypes. The DNA is really only a tiny part of the whole thing In order to calculate simulations, we first have to know how to build a mathematical model to do so. Our knowledge has far too many gaps to simulate but the simplest reactions and interactions.

The problem is that even with the increase they reported (maximum of about 4-fold increase) it is still far off. I have looked at data from large-scale trials about 2-3 years back and the increase would need to be much higher than that before it starts being economically sound. On top, the total yield is still very low, i.e. even with a massive upscale it would not even be close to put a dent on demand. Unless there is a massive breakthrough (and the mentioned article is quite a bit far off from that) it still requires much more research.

Wait... women? Those were women.... oh.

Grmbl. I know it is supposed to be funny, but several things bug me. a) evolution is not just a theory, b) I am not sure whether god is a proper hypothesis but worst of all C) if you wear gloves don't fucking touch your face!!!!

With regards to hydroxylation: hydroxylated multiwalled carbon nanotubes have been shown to be soluble in water with up to about 1 mg/ml. For single-walled I read up to 8 or 9, but I forgot whether they used hydroxylation or any other functionalization. I still do not fully understand your question though. Do you need a method to enrich nanotubes? If that is the question I would do a specific search for this in the literature because there are a lot of different approaches for that including phase-separation techniques. But I do not know the lit off the top of my head.

Do you mean carbon nanotubes? Unmodified they are pretty much insoluble. Dispersion The simplest way to disperse them is prolonged sonication, Depending on length it may not be very effective, however.

That is a very abstract concept that you propose and it seems to me to be outside of the realm of psychology, especially if defined as broad, it is not really quantifiable and becomes more a philosophical question. What psychologists have investigated in this context is how self-esteem affects relationships. If you love (or claim to love) someone from afar, you are appreciating a mostly abstract concept. your idea of a person that can be embellished as much as you want. The problem with accepting yourself and others is when the reality clashes with this fantasy, which is almost inevitable in a true long-lasting relationship. One of the issues for example is that if you are unable to accept your flaws, you may also have a harder time to accept them in other people, as they will never be as perfect as you imagine them to be. This is only a very crude example, but my point is that there are studies based on outcomes (familiar stability, depression, parenting efficacy etc.). But they are analysed in the context of interactions with other people.