AskScience AMA Series: I am Dr. John Nagy and I'm here to talk about Peto's Paradox and why larger mammals don't have higher cancer rates. Ask Me Anything! |
- AskScience AMA Series: I am Dr. John Nagy and I'm here to talk about Peto's Paradox and why larger mammals don't have higher cancer rates. Ask Me Anything!
- Would an Argon-Oxygen atmosphere be breathable?
- Alpha and Beta rays can barely get through a sheet of paper, How much mass do you need to block gamma rays?
- Cassini was launched in 1997, how come the photos it send back are HD on par with 2017?
- What's the amplitude of a electromagnetic wave ?
- Can atoms give up electrons that are not in the outer layer?
- Is there a logical reason as to why both variance and standard deviation are used?
- What happens to the energy in a Mains to USB adaptor?
- On Earth like planets (water/rock) would supercontinents be the norm? Or would we see most planets with fractured continents like present day earth?
- Is it possible to touch solid light?
- How to read the table in chapter 7 of "How to Teach Quantum Physics to Your Dog"?
- Are bananas more radioactive then other foods?
- Almost every structure we build contains cement, so when will we run out of the materials to make cement?
- Does a MRI affect the iron in the blood in anyway?
- Why is it that when you try to focus on 1 star it seems to slowly disappear, and when you focus your eyes just next to the star you see it sharply again?
- Could someone help fix my understanding of action potentials and the Na+/K+ pump?
- How does our body get rid of CO?
- How do geosynchronous satellites stay in one place?
| Posted: 16 Sep 2017 07:22 AM PDT Hello Reddit! I'm a mathematical biologist (@jdnagy96) studying why larger mammals don't have higher cancer rates--like why aren't all blue whales dying of cancer? This is just one of the many questions about cancer that evolutionary theory helps illuminate. We also work on how evolution causes tumors to become malignant and resist treatment. I'll be around in the afternoon (ET), so AMA! [link] [comments]  |
| Would an Argon-Oxygen atmosphere be breathable? Posted: 16 Sep 2017 05:01 AM PDT Could humans breath an Argon-Oxygen atmosphere? For bonus points: what about a Neon-Oxygen atmosphere? [link] [comments]  |
| Posted: 15 Sep 2017 01:20 PM PDT |
| Cassini was launched in 1997, how come the photos it send back are HD on par with 2017? Posted: 16 Sep 2017 12:28 AM PDT |
| What's the amplitude of a electromagnetic wave ? Posted: 16 Sep 2017 05:58 AM PDT Last day, in physics class, I learnt that mechanical waves have an "Amplitude". I wondered if an electromagnetic has one, and then what could be its value. (sry for my English ) [link] [comments]  |
| Can atoms give up electrons that are not in the outer layer? Posted: 16 Sep 2017 04:33 AM PDT There is no way for it to happen naturally that I know of, but can we force, for example Sodium, to not only give the one aelectron in its third outer layer, but to also give additional electrons from its second layer? [link] [comments]  |
| Is there a logical reason as to why both variance and standard deviation are used? Posted: 16 Sep 2017 06:20 AM PDT Given the mathematical relationship (squaring and square rooting) between the two of them, how come the other exists? Can't we just use standard deviation for everything, and in formulas just square the standard deviation? [link] [comments]  |
| What happens to the energy in a Mains to USB adaptor? Posted: 16 Sep 2017 04:41 AM PDT I suspect this could be generalised to any power brick. But here's what I know. Mains voltage runs at 240/250V (atleast here in the UK). The plug will have a transformer in it that steps the voltage down to the 5V necessary for USB compliance. Electricity flows when a circuit is complete. The input to the transformer forms a complete circuit; and when a device is connected to the output a current will be induced in the output of the transformers coil as that is also a complete circuit. But when a device is not connected to the output where is the energy from the completed input circuit going? [link] [comments]  |
| Posted: 15 Sep 2017 09:33 PM PDT |
| Is it possible to touch solid light? Posted: 15 Sep 2017 06:46 PM PDT I've been reading up on how scientists in 2014 forced light into a solid state, articles referring to them as creating light crystals. My question is, if all contact between regular matter is electrons within atoms pushing other atoms away, would it be possible for someone to touch a material made out of photons and if not how would regular matter and light crystals interact if they came into contact with each other? [link] [comments]  |
| How to read the table in chapter 7 of "How to Teach Quantum Physics to Your Dog"? Posted: 15 Sep 2017 05:36 PM PDT I'm currently reading this 'How to Teach Quantum Physics to Your Dog' by Chad Orzel - which I highly recommend. However, I am stuck in chapter 7. In particular, the explanation about the Bell theorem. I think I am not reading/interpreting the table in that chapter correctly. For what follows, it helps if you have the book in front of you. However, I'll try to explain what happens in that chapter for those who haven't. Those who have the book can skip to the question below :) Orzel presents a table that gives the possible outcomes of an experiment, as predicted by Local Hidden Variable Theories, in which two observers each have a photon detector. Each of the detectors is equipped with a polarized filter of which the angle can be varied. If I understand correctly, a source emits two photons of which the polarization is assumed to be the same (not sure about this, though). The Local Hidden Variable Theories assume that the polarization of both is a fixed value, but unknown. Now, the table I am talking about lists for each observer (Truman and RD) and each orientation (a,b or c) of the filter, the different possible outcomes (1 = photon detected, 0=not detected). See image Given that we have 2 possible outcomes and 3 orientations (a,b and c), there are 8 possible states (polarizations?) the photons can be in. QUESTION Now, on to the question. To get the predictions for the Local Hidden Variable Theories, we are supposed to determine the chance that Truman (observer 1) and RD (observer 2) measure the same outcome given different settings for the filters (a, b or c). The book states that this probability can not be lower than 33%. However, the book also states that we can 'play around with the probabilities of the individual states'. For example, the book states, we can avoid states 1 and 8. If we can select the possible states for the photon, shouldn't we be able to make the chance equal to 0? For example, I would think that if Truman chooses c and RD chooses a AND we make sure that the state is always 2, they should always get different outcomes. What am I missing here? I really hope that someone can help me out as I think this is the clearest book on this subject I have read. In particular, because Orzel does a good job at explaining the implications of QM. [link] [comments]  |
| Are bananas more radioactive then other foods? Posted: 15 Sep 2017 06:56 PM PDT Banana equivalent dose? Can somebody explain this to me? Are they just using bananas as an example or are they more radioactive than other healthy foods? I am paranoid to eat bananas lol. [link] [comments]  |
| Posted: 15 Sep 2017 05:58 PM PDT |
| Does a MRI affect the iron in the blood in anyway? Posted: 15 Sep 2017 08:25 PM PDT |
| Posted: 15 Sep 2017 10:26 AM PDT |
| Could someone help fix my understanding of action potentials and the Na+/K+ pump? Posted: 15 Sep 2017 06:26 PM PDT The simplified explanation I was taught goes like this: Non-gated sodium channels open following a stimulus. Once enough Na+ ions diffuse through these channels (as well as through the membrane to a lesser extent), the electrical charge reaches a threshold of -55mV, voltage-gated sodium channels also open, and the membrane depolarizes until it reaches around 30 mV. At this point, voltage-gated sodium channels close, voltage-gated potassium channels open, and K+ ion efflux repolarizes the membrane to a resting potential of -70 mV, at which point Na+/K+ pumps start to function. However, non-gated potassium channels are still open, and K+ ions are still diffusing out of the membrane through these leak channels, creating hyper-polarization. Na+ is stuck in the axon at this point, as well. The closing of the K+ channels, plus Na+/K+ pump activity, restores membrane charge to threshold, with Na+ ions on the outside and K+ ions on the inside. This explanation seems pretty flawed to me. The Na+/K+ pump transports 3 Na+ ions out for every 2 K+ ions it transports in. If it kicks in during the refractory period, which is caused by leak channels allowing the escape of positively-charged potassium ions, wouldn't it decrease the membrane's positive charge even further by forcing 3 positively charged ions out for every 2 it pushes in? How does the membrane return to resting potential? [link] [comments]  |
| How does our body get rid of CO? Posted: 15 Sep 2017 09:35 AM PDT Everyone knows haemoglobin prefers carbon monoxide over any other gas and that that is why it kills us. So how do our bodies get rid of it if they can't replace it with anything else? [link] [comments]  |
| How do geosynchronous satellites stay in one place? Posted: 15 Sep 2017 08:26 AM PDT |
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