- The extended warm period during the "boring billion" between 1.8 and 0.8 Gya is proposed to have been the result of atmospheric N2O being 10x higher than it is today. Where did all the N2O during that period come from?
- Have there been any attempts to build a solid rocket motor that can be throttled or turned off?
- Why do some people who've recovered from covid-19 not develop anti-bodies?
- What is the difference between the original sars cov 2 and its variants?
- Is there a scientific consensus on optimal learning sessions and study time management?
- Are July and August borns disadvantaged in school and life?
- What happens EXACTLY at the triple point of a pure substance?
- Do other force particles have a spectrum like photons?
- How many, and which viruses are the cause of cold? And why is cold more likely to happen in cold environments?
- What new, ground-breaking technologies were first used in the creating of the first satellite (Sputnik 1)?
- Which oak species are most likely to successfully take during a graft? (Unfamiliar with cladistics)
- What was on the opposite side of the Earth when Pangea existed?
| Posted: 22 Oct 2021 09:39 AM PDT During the boring billion global temperatures were about 4 ºC higher than today due to higher concentrations of greenhouse gases. Scientists have ruled out CO2 as the culprit due to the lack of evidence of ocean acidification. Methane has also been ruled out as it is only biogenic and methanogens are unlikely to have produced enough methane. So scientists seem to have settled on N2O as the offending greenhouse gas, with Proterozoic levels proposed to be elevated 10x over modern levels. Today, most N2O is either anthropogenic or biogenic, with only a small fraction being formed abiotically. If methanogens were unlikely to produce enough methane to significantly affect the climate, how would denitrifiers be able to produce enough N2O? If the elevated levels were abiogenic, why don't those processes continue today? [link] [comments]  |
| Have there been any attempts to build a solid rocket motor that can be throttled or turned off? Posted: 23 Oct 2021 07:43 AM PDT It seems like there would be a lot of applications for a small solid rocket motor that can go from ~0% to 100% or possibly greater. I'm imagining something like a JATO rocket in terms of size and the creative ways it has been implemented. It could be something simple such as a mechanism to destroy sections of the propellent and spit out the chunks. It couldn't throttle back up and will spike thrust briefly but it still sounds useful. [link] [comments]  |
| Why do some people who've recovered from covid-19 not develop anti-bodies? Posted: 23 Oct 2021 12:36 AM PDT My basic understanding of immunity is that the first time you get a virus, your immune system makes anti-bodies, which then neutralise the virus, and the anti-bodies remain in your blood stream afterwards. Then if the virus re-infects you, the anti-bodies are already there, ready to neutralise it again. But there's a study which shows a third of people who've recovered from covid do not develop anti-bodies. Why/how does this occur? [link] [comments]  |
| What is the difference between the original sars cov 2 and its variants? Posted: 23 Oct 2021 08:22 AM PDT I'm basically asking about differences in spread/transmition and severity (hospitalization and deaths). Are there any data on that? Im more interested in the Delta Variant, but any data is welcome. [link] [comments]  |
| Is there a scientific consensus on optimal learning sessions and study time management? Posted: 22 Oct 2021 08:17 AM PDT Hello there, I've been having a hard time finding data regarding this side of psychology. While I've found actual papers regarding the usefulness of note-taking under the form of mind maps rather than usual note-taking methods, I can't find enough papers regarding focus time. We hear advices here and there - I've had high school teachers saying "we can't focus more than 1 hour at a time", I've seen the pomodoro (25 minutes of work / 5 minutes of rest + other arbitrary rules) technique, but it doesn't seem to be a strong research field. I'm mainly using google scholar for my researches, so maybe my method for searching papers isn't as good, which is why I'm asking for some guidance : does science say anything about how we should focus in order to maximise learning and optimize our time? Thanks! [link] [comments]  |
| Are July and August borns disadvantaged in school and life? Posted: 22 Oct 2021 11:13 AM PDT There is research suggesting that children born in July / August struggle more in school, struggle with reading and writing, more likely to drop out, and be diagnosed with ADHD. Here in England, a child born in September will turn five shortly after the start of term. A child born in July could will be four for the entire school year. How true is this and is your child doomed if born in July / August? Here is just one article talking about it. Apparently parents are holding their children back a year to offset this problem but is this a good idea? link [link] [comments]  |
| What happens EXACTLY at the triple point of a pure substance? Posted: 22 Oct 2021 09:15 AM PDT I'm working on a problem for a binary mixture which is equivalent to the triple point of a single-component system, and that is this: What are the relative amounts of each phase EXACTLY at the triple point? Most descriptions you find say something along the lines of "all three phases can exist simultaneously," but "can" implies that they don't always. And if that is just bad wording, how do you calculate how much of each phase is present, i.e., the phase fractions? I know that both realistically and numerically speaking, this is not a meaningful question as you can never be exactly at any given point. My question is, then, a purely mathematical one, assuming that the equations used to model a system have an exact solution. At the triple point of a pure substance (or a three-phase point of a binary mixture with one state variable fixed), there are zero degrees of freedom which can be verified using the Gibbs Phase Rule: DOF = C - P + 2 For a pure component, you get DOF = 1 - 3 + 2 = 0, and the binary mixture with one parameter fixed, you get (DOF) - 1 = (2 - 3 + 2) - 1 = (1) - 1 = 0. This means that the thermodynamic state of the system is completely fixed and that all other state variables can (theoretically) be determined from those conditions. However, in practice, most systems that I'm familiar with which have more than one phase present have at least 1 DOF, and varying that DOF changes your phase fraction(s). For example, a binary mixture with two phases has 2 DOF. Specifying, for example, temperature and avg. composition fixes the system state and allows you to calculate the individual phase compositions and thereafter the phase fractions from a mass balance/lever rule. You can also do the same with a ternary mixture and three phases using two independent equations to calculate the two independent phase fractions (all three sum to 1, so two are independent). You can't, however, do that here because there is not enough information available to calculate two independent phase fractions. There couldn't possibly be; not with state variables anyway. If you try (and I have), you get infinitely many solutions/a line in the space of the phase fractions. Plot of mass balances for 3C/3P system (axes are the independent phase fractions). All this is leading me to one of the following conclusions:
The first of these makes a sort of logical sense to me but doesn't really make physically sense, because this would imply that either phases don't exist (which seems ridiculous) or the whole system is at all three phases simultaneously (equally ridiculous). The second is more likely in my mind, and I can find some analogues in systems with fewer phases, e. g., a single component at two phases has 1 DOF (e.g. pressure) yet still needs a value for work/enthalpy supplied to determine a phase fraction. That said, I haven't found any evidence to support this nor have I found any discussion of it online or in the scientific literature. Any thoughts would be greatly appreciated! [link] [comments]  |
| Do other force particles have a spectrum like photons? Posted: 22 Oct 2021 09:04 AM PDT Photons carry the electro-magnetic force and operate on a spectrum based on their energy, giving us things like heat and x-rays. Do the force particles that carry the other natural forces also behave differently at different energy levels? Is there (or could there be) a spectrum of the nuclear forces, or of gravity? [link] [comments]  |
| Posted: 22 Oct 2021 12:50 PM PDT |
| Posted: 22 Oct 2021 08:46 AM PDT creation* made a typo in the title. Sorry! What technologies made Sputnik 1 so special? [link] [comments]  |
| Which oak species are most likely to successfully take during a graft? (Unfamiliar with cladistics) Posted: 22 Oct 2021 08:10 AM PDT https://imgur.com/gallery/7W0fZxD Marked is the species that I want to work with. I imagine that the oaks between and including Quercus lyrata to Quercus Muehlenbergii would successfully take. But how far up, and how far down, do you suspect that the trees are similar enough to successfully graft? [link] [comments]  |
| What was on the opposite side of the Earth when Pangea existed? Posted: 22 Oct 2021 08:01 AM PDT |
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