source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-1601 | microscopy, histology, fluorescent-microscopy
If I need a fluorescent one, wondering if there is anything else needed, like special lighting or special materials for tagging the cells, which seems like it might require extra stuff like centrifuge and who knows what else.
Samples can sometimes have autofluorescence (e.g. the chitin that makes up the cuticle of insects is autofluorescent) but most samples are not. Almost always a fluorophore is used to stain the specimen for something. These can be cheap or very expensive, depending on what you want to stain. This really depends on your sample and how it is prepared. And know that most 'good' samples' are dehydrated or are treated by chemical fixation, which requires chemicals you cannot usually find at a local pharmacy. It depends on how ambitious you want to get as an amateur microscopist!
Also, you won't need a centrifuge.
For the histology slides, wondering generally what it takes to do that too, if I can get by with a regular microscope.
You can get by with a regular upright widefield microscope for sure. If you perform the sectioning well (making thin slices of your sample) then even basic microscopes will produce fascinating images, provided your lighting is good. It helps to have a condenser or a nice lamp and some thin and clean glass slides for well illuminated images.
Maybe fluorescent microscopy requires advanced biotechnology of some
sort, which is sort of what I'm wondering, what the basics are.
It requires a little bit more optical work. I would stay away from it unless you are serious, because it takes quite a bit more work and equipment to make it minimally workable. Normal microscopy is certainly a lifetime of fun if you have the desire to find interesting samples and work to make them good for imaging.
Addendum: the principle of fluorescence microscopy is quite simple but aligning everything is actually quite difficult if you are an amateur with no specialized tools. Here is the principle only, notice how the input and output must be aligned and the small objective lens has to transmit both excitation and reflected light:
The following is multiple choice question (with options) to answer.
A microscope is useful for looking at | [
"giraffes",
"trees",
"butterflies",
"sea life"
] | D | microscope is used to see small things by making them appear bigger |
OpenBookQA | OpenBookQA-1602 | • I think the gif dosn't really fit this site, though I can't say if there is a specific rule against such things – Yuriy S Oct 10 '16 at 11:27
• @YuriyS: Hmm ... I am sorry to learn that people may find it inappropriate! That was by no means my intention! Do you think it would work better by removing the gif an leave the link and the figure of speach, or are all of those opfuscating the points I tried to make? – String Oct 10 '16 at 12:21
• @String: your link to a cartoon movie of a dead animal being bludgeoned is disproportionate and offensive. – Rob Arthan Mar 12 '17 at 1:27
• @RobArthan: Sorry, in some parts of the world such a cartoon would be considered merely a funny way to illustrate the saying about beating a dead horse. No offense intended, only a light tone. I cannot help that people do take offense, so I have removed it. Still it puzzles me how a cartoon matching the content of a saying would offend. I am from Denmark, after all. – String Mar 12 '17 at 8:11
• @String: on MSE it's easier just to use neutral language. As I am English (after all), may I point out that the cliched phrase is actually "flogging a dead horse" and it doesn't have the connotations you think it does (it's not "explaining to death", it's using a tired old argument that has lost all interest or relevance). Your cartoon doesn't help with that. – Rob Arthan Mar 13 '17 at 1:55
1. Well... yes... it does break down. You assumed that there are only 6 primes and reached a contradiction. You've successfully proved that there aren't only 6 primes.
2. Under the assumption that there are only 6 primes 30,031 isn't factorizable.
The following is multiple choice question (with options) to answer.
A pony is living in a small barn and its owner dies and the pony is unable to fend for itself. The pony dies because | [
"it is elderly",
"it is bored",
"it is vital",
"it required nutriment"
] | D | lack of food causes starvation |
OpenBookQA | OpenBookQA-1603 | thermodynamics, thermal-radiation, thermal-conductivity
Title: What can I do to be invisible for the IR-camera on board of a police helicopter? I think we all have seen the images of crime suspects, running in the dark of the night to escape the police, made with the help of infrared cameras. What can I do to be invisible to these cameras when I run from a bank I just robbed, through gardens, jumping over fences, but not running through long tunnels, or through woods with densely packed trees? When I run without having done anything (except robbing the bank) I show up on the screens connected to these cameras as a highlighted "blob" looking remotely human.
Should I wear a suit filled with ice, enclosing my entire body? Or would that also be visible, because in that case, I can imagine you see a dark human blob on the screen because the temperature of that suit is lower than my surroundings (unless it's a cold winter night, but let's assume it's a normal summer night or winter night if I lived on the southern hemisphere).
Should I wear a suit with excellent heat-isolation enclosing my body and which I've prepared in such a way that it has the same temperature as the air that night?
Keeping something (a big heat-isolating plate) above my head seems unpractical to me, and some parts of my body will certainly show up on the screen helicopter with the cops in it.
What else can I do to be invisible while still being able to run freely?
By the way, I'm not planning anything... Military gear is typically pretty good at trumping police gear. BAE systems recently came out with an adaptive camouflage system that can make a tank's IR signature look like anything they please
The next best approach is probably confusion. There's a long history of using Craigslist to put a "want ad" for people dressed exactly like you, then you rob a bank and the police don't know who to go after.
Failing that, an IR camera picks up heat, so anything highly insulative will be effective. My recommendation is something fuzzy, or made of foam. The fuzzy things tend to stay very close to room temperature
What could possibly go wrong.
The following is multiple choice question (with options) to answer.
Personal protection equipment is essential when | [
"experimenting with volatile and vaporous liquids",
"dumping lab rats in the incinerator",
"interfacing with tenured professors",
"wearing a sports cup"
] | A | safety goggles are used for protecting the eyes during experiments |
OpenBookQA | OpenBookQA-1604 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A person wants to signal to another person, but is lacking a flashlight. They can | [
"shuffle sunlight with mirrors",
"direct sunlight with cones",
"direct others with glass",
"direct shades with hands"
] | A | a mirror is used for reflecting light |
OpenBookQA | OpenBookQA-1605 | zoology, behaviour, mammals, rodents
Title: Why do Guinea Pigs chirp / sing? Ok, so this appears to be quite a mystery. Me and my girlfriend have 2 Guinea Pigs, 1 male and 1 female.
My girlfriend once picked up the female one and took her outside into our garden. The Guinea got scared for some unknown reason and jumped out of my girlfriend's arms and fell down hard.. That night, the female Guinea woke us up with some very strange sounds. She sounded like a chirping bird.
Since then, she sometimes repeats these sounds (most often at night, but not always). Mostly, we are puzzled as to why as there is often no apparent reason for her sounds. Also, when she makes the sounds, she appears to be in a trance-like state, making no movements at all.
Looking for the answer online I found many discussions on the subject like this one or this one. Mostly, the sounds (and the often mentioned trance like behavior) appear to be interpreted as either (1) alarm sounds, (2) loneliness sounds or (3) happiness sounds.
There are also recordings of it one Youtube, like this one.
What I was wondering:
Does anybody know about some actual research that has been committed on this subject? If so, what were the results?
I'm just so very curious to find out! I found this question very interesting so I did some research. Here's a brief summary of what I've found:
Researchers have found that there are 11 different call types. Some of these include a "sharp alarm cry", "sociable clucking", chutter, whining, purring etc. Using body position and behaviour, researchers attempted to associate these vocalizations with behaviour. Some vocalizations had no apparent associated action including what researchers designated the "chirrup" ( I think this is similar to what your guinea pig might have emitted.)
For more information you can read the results section of this paper by Berryman. You can find a full description of each of the 11 calls and their assumed cause or purpose. Some involve social interaction, reproduction, and distress. Much of the research regarding Guinea pig vocalization involves communication and response between mothers and pups.
In short, it seems as though this chirping behaviour your Guinea pig is exhibiting is normal, but not of any known cause.
The following is multiple choice question (with options) to answer.
Mammals with blow holes can hear signals called | [
"radio waves",
"air horns",
"people talking",
"clicks"
] | D | sound can be used for communication by animals |
OpenBookQA | OpenBookQA-1606 | atmosphere, climate-change, thermodynamics, radiative-transfer
All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.
Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: Dubai construction alters local climate
Additional references
Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution
of global anthropogenic heat flux. Atmos. Oceanic
Sci. Lett., 5, 108–112.
The following is multiple choice question (with options) to answer.
When there is an increase in atmospheric temperature, then | [
"glaciers become too large",
"global sea level decreases",
"Antartica and Greenland icebergs will melt",
"Earth absorbs less sunlight"
] | C | if the atmospheric temperature rises then the glaciers will melt |
OpenBookQA | OpenBookQA-1607 | zoology, ethology, behaviour, psychology, death
I can't prove it to you, but I know that my Beagle had a rich emotional life. I know this because I spent huge amounts of time with him. He was a close friend of mine. I would just as soon question whether my wife has real emotions as my dog. I can't prove that my wife's emotions are real either, but I don't have to. It would be silly to assume that everything she shares with me is some sort of evolutionary programming, and not real emotion. Now, when I extend this to cetaceans, I must admit that I don't have any friends in those circles. So I can only guess.
The following is multiple choice question (with options) to answer.
An example of an instinctive behavior could be | [
"wind",
"fire",
"revenge",
"air"
] | C | An example of an instinctive behavior is a baby bird pecking at its shell to hatch |
OpenBookQA | OpenBookQA-1608 | electromagnetic-radiation
Here is something you can do for fun and might be instructive too. Get a small portable AM radio and tune it between stations. Now move it around near your computer when the computer is running. You will hear all kinds of strange noises. The noises might even change somewhat depending on what the computer is doing. Now go do the same thing to other electronic devices. If you think the computer was noisy, try holding the radio near your refigerator when its running, near your fuse box, or near your car with the hood up. There is a lot of low power RF floating around, with disk drives being very very tiny sources in the scheme of things.
The following is multiple choice question (with options) to answer.
Several batteries placed into a radio will make sound after first using | [
"solar energy",
"wind energy",
"chemical energy",
"elbow grease"
] | C | a battery converts chemical energy into electrical energy |
OpenBookQA | OpenBookQA-1609 | ornithology
Title: How do birds learn their tunes in isolation from their own species? I wonder what a bird would sing if it didn't have its parents around (or any other birds for that matter) to learn its chirping sounds from.
I'm interested in how a bird would sing...
in complete isolation from creatures communicating through sound;
in isolation from its own species, but with other birds;
in isolation from all birds (other animals and creatures are there for it)
For example,
Would a bird even feel the need to speak up if there wasn't any other vocalizing creature around?
Would a bird learn other species' signals? Would it only learn from one species, the one which it would think of a fitting mate?
Would a bird try to mimic a non-flying creature's signals?
These are similar questions, but if you think they should be separated, let me know in the comments. Birds have to learn their song patterns.
They are able to chirp, but the songs with "meaning" are learned from their parents or whatever they learned to be their "parent".
Here is a paper that related bird song learning to human learning (of speech, for example).
Birds brought up by parents from another species learned to sing their songs.
There are many birds that learn to imitate other animals or sounds, so in isolation from all birds they will probably do this.
I can't recall where, but I read a paper once, where little finches brought up by humans developed a song resembling the "Hello there, now there's food", their caretaker always greeted them with. (Not the speech, but the overall sound pattern.) They might not understand the signals, but they try to communicate nevertheless. Some birds use sound from other species to mock others, scare them off or lure them into thinking they might be more powerful than they are.
Birds brought up in total isolation do sing, but not the typical songs you know from their species. Deaf birds who can't hear themselves, though, do not (always) sing.
The following is multiple choice question (with options) to answer.
Humming birds help with the growth of | [
"raspberries",
"cars",
"buildings",
"wind"
] | A | A bird is a pollinating animal |
OpenBookQA | OpenBookQA-1610 | optics, atmospheric-science, weather
Title: Explanation for an unexpected rainbow Yesterday, I observed an unexpected rainbow in the sky. There was no forecast for rain, neither was it raining anywhere nearby. I have been trying to find an explanation but don't seem to find any. Can someone please explain what this rainbow is?
Note:the colours were way more vivid as compare to the picture I have taken These are tropospheric Iridescent Clouds
According to AtmosphericOptics:
When parts of clouds are thin and have similar size droplets, diffraction can make them shine with colours like a corona. In fact, the colours are essentially corona fragments. The effect is called cloud iridescence or irisation...
The usually delicate colours can be in almost random patches or bands at cloud edges. They are only organised into coronal rings when the droplet size is uniform right across the cloud. The bands and colours change or come and go as the cloud evolves...Iridescence is seen mostly when part of a cloud is forming because then all the droplets have a similar history and consequently have a similar size.
I've saturated the image so the interesting part can be appreciated
And here you have a very similar observation I quickly found by google image search:
The following is multiple choice question (with options) to answer.
A rainbow is caused by rain and what? | [
"grass",
"winds",
"solar rays",
"oceans"
] | C | sunlight and rain can cause a rainbow |
OpenBookQA | OpenBookQA-1611 | physical-chemistry, water, heat
What do you want to do with the hot water? Swim in it. I was thinking
of thousands of liters
That's an interesting idea, but unfortunately, I don't think adding chemicals to a pool in order to heat it is a good idea (especially yellowish chemicals). The water temperature would drop in a few hours, tops, and you'd have to be constantly adding more chemicals to it. At some point, you'd have a pool of chemicals instead of a pool of water. Not to mention that the chemicals would probably end up being more expensive than the electricity or the gas bill to heat up the pool to the same temperature the conventional way.
A nice way of heating up pools is using solar water heating systems, and coupling them with the conventional heating systems, if necessary.
So... Is it feasible? I'd say it isn't. But since you said this was more of a thought experiment... The only scenario I can imagine where the best solution to heat up a pool is to add chemicals to it is: You have a small pool, very little time to heat it up, you want to heat it up to sauna-like temperatures, and although you'll only use it for a couple of hours you are willing to spend a lot of money to do so. In this case, I'd add some water to the pool, and then add the following reagents to it, making the following reaction:
$$\ce{NaOH + HCl -> NaCl + H2O} \\ \Delta H = -56\,200\ \mathrm{\frac{J}{mol}}$$
You can do the math, but I assure you it heats up pretty quickly. We used to neutralize concentrated acid in ~10 L plastic buckets, and if we "accidentally" neutralized too much at a time the bucket would start to heat up to a point you couldn't even touch it.
NaCl is kitchen salt, so no issues with toxicity if you do the math correctly. Salt water also makes you float better, which I think is a nice quality in a pool. There would be salt on the bottom, but I think that's nice too, makes it feel like the sea.
The following is multiple choice question (with options) to answer.
A person takes a bucket full of water and adds it to a full pool. After adding fifty buckets of water to the pool, it | [
"drains",
"dries",
"bloats",
"sinks"
] | C | as the amount of water in a body of water increases , the water levels will increase |
OpenBookQA | OpenBookQA-1612 | star, galaxy
If you're on a farm, away from cities, in a place with reasonably low light pollution, and your eyes are good, and you've been sitting in perfect pitch black darkness for at least 30 minutes prior - when you look up you can reasonably expect to see a few thousand objects, mostly stars. Keep looking, and after a while you will distinguish one or two thousand more stars, very faint, that you could not see at first sight. Practice this steadily for a few years, and you'll add maybe another thousand; but you won't be able to see those all at once - only one at a time.
Now travel to the Cerro Tololo site in Chile, up in the mountaineous desert, zero light pollution, excellent transparency, and you'll multiply all those numbers by a factor of 2x ... 5x.
As you can see, the numbers are very flexible because there are so many factors involved. You can't just slap a 44k label on it and call it a day; that doesn't make any sense in reality. Astronomers know that the pure magnitude number doesn't mean much by itself, because it is just one factor among many.
In a place with very high light pollution (like where I live, in the middle of a large, dense, sprawling urban area in California), you'd be lucky if you can see a hundred stars at night.
Or, in a place with zero light pollution, shine a flashlight into someone's face, and you've temporarily blinded them. You've reduced the number of stars they could see by an order of magnitude for the next half hour (night vision gradually recovers, and it takes 30 minutes to fully recover, according to US military manuals and visual astronomers practice).
The following is multiple choice question (with options) to answer.
the night sky shows very far away what | [
"clumps of flaming gas",
"tidal waves washing over beaches",
"party balloons tied to houses",
"aircraft falling towards collision"
] | A | a star is made of gases |
OpenBookQA | OpenBookQA-1613 | geology, crust, geobiology
Title: Does crustal thickness have anything to do with how life existed and sustained on Earth? The original question that was put on hold "If the crust were the thickest layer of Earth, what effect would its thickness have on organisms?" was actually one of those 'counterfactual question' found on my science book, and it was really just a 'reflect upon' question. And it's actually a hard one for me to answer since it's 'what if?'s. So by revising, it would still confuse some poeple, but I guess it's already specific on its own. But I still find it hard.
Follow up question:
And what if it ever was thicker than the mantle or the rest of Earth's layers, can the planet still sustain biological life? If the crust were the thickest layer or Earth, several things would happen:
It wouldn't be a "crust" any more, by definition. Because this is what a "crust" is: a thin layer on the exterior of something. However, if we assume that the mechanical properties of the crust (being cold and brittle etc) would extend deeper in the Earth, the following applies.
No mantle convection, or at least mantle convection weak enough to probably not affect the surface. Therefore, no volcanoes, no mountain building, no subduction, no recycling of volatile elements, no sub-seafloor hydrothermal vents.
If it's cold enough, the core probably solidified and there is no magnetic field.
A good example would be Mars. A planet hypothesised to have tectonic activity in the past, but not any more. The crust of Mars isn't the thickest layer (again - think of definitions), but it is thicker in absolute and relative terms when compared to Earth. I will leave the implications of "Marsifying" Earth on organisms for you to figure out.
The following is multiple choice question (with options) to answer.
You can find what on the crust of earth | [
"clouds",
"stars",
"air",
"worms"
] | D | the crust is a layer of the Earth |
OpenBookQA | OpenBookQA-1614 | gravity
Title: Is the gravity on Kepler 39b higher than on the Sun? According to the formula for gravitational acceleration $a = GM/r^2$ where $G=6.674 \times 10^{-11}$, Jupiter with mass 1.89813 × 10^27 kg and radius 69,911,000 m gives a gravity around 25m/s^2. The Sun with mass 1.989 × 10^30 kg and radius 695,510,000m will have a gravity around 270m/s^2.
But using the data for Kepler 39B, mass 18 times that of Jupiter 3.416634 × 10^28, and radius about 5/4 of Jupiter's 87,220,000m, I get almost 300m/s^2, higher than the Sun's.
Is this right?
I did and redid it, and still concerned that I am doing something wrong. You are probably overlooking why the radius is what it is, or equivalently why the planet is denser than the Sun.
The Sun is undergoing fusion in its core, which releases energy, which causes it to expand (though it achieves an equilibrium state, as expansion decreases rate of fusion which leads to contraction, which leads to accelerated fusion which leads to expansion...). Jupiter-like bodies, however, don't produce heat from fusion (except maybe some deuterium fusion very early in their lives); they slowly cool and contract over time. So such a body can compress into a denser state, allowing it achieve higher surface gravity (give or take difficulties in defining "surface" for a gaseous body).
Eyeballing the calculation, you can see that the sun is 10 times the radius of Jupiter and 1000 times the mass, so it's surface gravity should be about $1000/10^2=10$ times greater than Jupiter's, which is what you find. But Kepler 39b is 18 times more massive than Jupiter and only marginally larger. That's a big uptick in density. So that it's surface gravity would be about $18/(1.25)^2=11.52$ times stronger than Jupiter's (also what you find). And $11.52>10$, so Kepler 39b has higher surface gravity.
The following is multiple choice question (with options) to answer.
As a Red Giant forms it's gravity will | [
"grow",
"fluctuate",
"shrink",
"reverse"
] | A | as mass of a celestial body increases , the force of gravity on that planet will increase |
OpenBookQA | OpenBookQA-1615 | development, morphology
Title: Are there special constants in biology that define organism's morphology? In math, there are special numbers, like Pi (3.14159...) and e (2.71828...). In chemistry, there's numbers like avogadro's number (6.0221413e+23). For example a circle can be defined in terms of 2 * Pi.
Are there any significant constant numbers in biology that define the shape of an organism (ex: mammal)? I'm talking about stuff like shoulder to hip ratio or length of an organism, etc?
Here's an example that came to mind - different fetuses developing into different organisms. Is there any constant that is the same for these at some stage of development? Like the ratio of head to tail? I don't know if this is what you mean, but take a look at BioNumbers.
Also, mathematical constants like pi are different from physical constants. Mathematical constants are true in a mathematical (logic) sense, and do not need to be related to any physical quantity. They are derived by logic. Physical constants, on the other hand, typically describe an observed relation between two types of quantities. They are derived by measurement.
The following is multiple choice question (with options) to answer.
what determines the number of body parts and organism is born with? | [
"survival of fittest",
"random chance",
"the organisms creators",
"natural predators"
] | C | the number of body parts of an organism is an inherited characteristic |
OpenBookQA | OpenBookQA-1616 | evolutionary-algorithms, neat, fitness-functions, fitness-design
But this blows up the score too much and now the food quality is not respected and they just gulp on anything slightly above 0. A human analogy can help you here (a variance).
Initialize all the agents with an initial value $x$; we will call this energyUnits. I Will talk later more about this.
Now, add some value, as an incentive, whenever the agent eats good food, to the energyUnits. You need to add a function that will keep decrementing the value of the agent's energyUnits, as humans degrade energy (calories) with time. We will call this function normalDegrade. This is the core part of the solution for your problem.
Now, for the bad (or poisonous) food you can be more creative with. You can simply subtract a given value whenever an agent eats poisonous food. Or you can extend your normalDegrade function with a very high downward slope. In this case, the energy units (value) of the agent will fall very rapidly. This will force the agent to look for good food to survive.
Since the ratio of food is 9:1 with poisonous, you need to initialize the value of $x$ (energyUnits) very high. You need to do some trial and error to find the right fit for you here.
Also, I am assuming that the agent is being removed from the population whenever the value of $x$ is zero or some negative value (which depends). This is important, as it makes sure that the algorithm is not wasting time in processing bad agents.
Because of this, another problem arises of the population coming to extinction. For this, you need to keep generating new agents for which any of the genetic algorithms will do. A new population with better parents of the already present generation will keep the population fit and efficient.
A good fitness function is a core to solving any problem of this kind, and sometimes it is hard to find. You might need to do some trial and error with different values to look for the right fit.
The following is multiple choice question (with options) to answer.
When you increase the viability of food, you increase the ability to | [
"waste it",
"modify it",
"disperse it",
"displace it"
] | C | as ability to preserve food increases , the ability to transport food increases |
OpenBookQA | OpenBookQA-1617 | evolution, zoology
Title: Why are hens so different from other birds? Hens lay many eggs during their lifetime (at least, I don't know of one which can lay more eggs) and they can't fly. Compared to other domestic animals it seems to me they are the least capable of defending themselves or escape if it comes to be left alone in open wild. What is their evolutionary story? Domestic organisms are bred to serve specific purposes for humans. Sheep are bred to produce wool; Cows are bred to provide meat and milk for human consumption; dogs are bred for service and companionship. Since domestic animal do need to survive in the wild in order to reproduce (ignoring feral animals, which is an interesting topic by itself), most of the other aspects of that animal relevant to its survival tend to be minimized.
So one could just as easily point out that there is no other animal that produces as much wool as a sheep, and yet producing copious amounts of wool isn't particularly useful to the animal itself (i.e. other than the fact that humans will tend to select good wool producers for breeding). So sheep are not particularly good at surviving in the wild, and yet they are incredibly successful as a species and are widely distributed, thanks to humans.
In short, domestic hens evolved to produce many eggs in their lifetime because over the past millennia since humans have started keeping them as livestock, humans tended to preferentially breed those individuals which produced more eggs and to eat those individuals which did not. Chickens tended to be kept in pens and guarded by humans or other animals, so the ability to defend themselves or flee from danger was not important to their survival, and in fact, those that did attack their handlers or escape were probably less likely to be bred.
This process is known as selective breeding or artificial selection.
The following is multiple choice question (with options) to answer.
An example of an adult animal laying eggs is all aside from | [
"penguins",
"snakes",
"turtles",
"kittens"
] | D | some adult animals lay eggs |
OpenBookQA | OpenBookQA-1618 | genetics, vision, sex-chromosome, color
Females have two X-chromosomes, and can either be homozygous or heterozygous for the X-chromosome opsin allele. If homozygous, they are dichromatic; however, females who carry both an allele for an L opsin and one for an M opsin have the equivalent of normal human color vision, having both L and M cones because the process of X-inactivation segregates the expression of the L and M opsin genes to separate populations of cones. The significance of this is that in trichromatic female squirrel monkeys, the difference between L and M cones is solely determined by the stochastic choice of which X-chromosome is retained as the active one. Variation in L:M cone ratio in female squirrel monkeys is similar to what is seen in human males with normal color vision. In squirrel monkeys the variation has been attributed to the stochastic process of X-inactivation, influenced by the number of cells present at the time of activation and other random factors in the inactivation process (Jacobs & Williams, 2006).
Boiling this down: X-inactivation happens at a local enough scale that eyes of heterozygous females have active versions of both normal and mutant opsin genes. So they will still see color "similar to what is seen in human males with normal color vision".
Note of course that people with an XX complement can have better possible color perception than XYs, as they have the potential for tetrachromacy:
females who are heterozygous, for example, having OPN1LW genes that encode two spectrally distinct L pigments, would have four different cone types -- two different L, plus M and S -- and thus the potential for having tetrachromatic color vision (Bosten, Robinson, Jordan & Mollon, 2005, Jordan & Mollon, 1993, Jordan & Mollon, 1997). Prior to the discovery of variation in peak sensitivity of pigments underlying normal color vision, it had been appreciated that female carriers of a red-green color vision deficiency have the potential for tetrachromatic color vision (Nagy, MacLeod, Heeyndermann & Eisner, 1981).
The following is multiple choice question (with options) to answer.
A couple having a baby want to guess if the child will share the same eye color as mother and father so they | [
"chart the likelihood",
"pray for peace",
"take a vacation",
"inject a dye"
] | A | a Punnett square is used to identify the percent chance of a trait being passed down from a parent to its offspring |
OpenBookQA | OpenBookQA-1619 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A person is able to tell what shape a toy is by holding it in their hands and also | [
"making",
"eating",
"crying",
"noting"
] | D | seeing is used for sensing visual things |
OpenBookQA | OpenBookQA-1620 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
When a squid moves forward, water is | [
"pushed directly behind it",
"pushed up and below it",
"evaporated by salt water",
"pushed in front of it"
] | A | a squid produces thrust by pushing water out of its body |
OpenBookQA | OpenBookQA-1621 | c#, design-patterns, beginner, classes
//Happiness relates to playing with the pet
public PetMood Mood { get; protected set; }
//Pet hunger level
public HungerLevel Hunger { get; protected set; }
//Has the pet been vaccinated
public bool IsVaccinated { get; private set; }
//The pet class constructor
public void GivePetShot()
{
IsVaccinated = true;
}
public virtual PetMood PlayWithPet()
{
var message = GetPlayWithPetMessage();
if ( (int)this.Mood < 4 )
{
Console.WriteLine( message );
return this.Mood += 1;
}
Console.WriteLine( message );
return this.Mood;
}
public abstract string GetPlayWithPetMessage();
public virtual PetMood PunishPet()
{
string message = GetPunishPetMessage();
if ( (int) this.Mood > 0 )
{
Console.WriteLine( message );
return this.Mood -= 1;
}
Console.WriteLine( message );
return this.Mood;
}
public abstract string GetPunishPetMessage();
public virtual HungerLevel FeedPet()
{
if ( (int)this.Hunger < 3 )
{
Console.WriteLine( GetFeedPetSuccessMessage() );
this.Hunger += 1;
return this.Hunger;
}
Console.WriteLine( GetFeedPetFailedMessage() );
return this.Hunger;
}
public abstract string GetFeedPetSuccessMessage();
public abstract string GetFeedPetFailedMessage();
public HungerLevel StarvePet()
{
string message = GetStarvePetMessage();
if ( (int)this.Hunger > 0 )
{
Console.WriteLine( message );
this.Hunger -= 1;
return this.Hunger;
}
Console.WriteLine( message );
return this.Hunger;
}
public abstract string GetStarvePetMessage();
public void UpdatePet( HungerLevel hunger )
{
if ( hunger != Hunger )
{
Hunger = hunger;
}
}
public void UpdatePet( PetMood mood )
{
if ( mood != Mood )
{
Mood = mood;
}
}
The following is multiple choice question (with options) to answer.
A bunny is desperate for food and happily chows down when offered | [
"a meatball",
"some oregano",
"cat food",
"a steak"
] | B | rabbits eat plants |
OpenBookQA | OpenBookQA-1622 | Question
(a) The “lead” in pencils is a graphite composition with a Young's modulus of about $1 \times 10^9 \textrm{ N/m}^2$. Calculate the change in length of the lead in an automatic pencil if you tap it straight into the pencil with a force of 4.0 N. The lead is 0.50 mm in diameter and 60 mm long. (b) Is the answer reasonable? That is, does it seem to be consistent with what you have observed when using pencils?
$1.2 \textrm{ mm}$
Solution Video
# OpenStax College Physics Solution, Chapter 5, Problem 31 (Problems & Exercises) (1:30)
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## Calculator Screenshots
Video Transcript
Submitted by shelby.keith on Mon, 02/25/2019 - 20:55
Good solution
Submitted by C-Mak Breezy on Wed, 11/27/2019 - 08:05
How come when I put the equation '0.50x10^-3/2' it gives me 2.5x10^4? Your solution is showing the result as 0.25x10^3. Am I missing something?
Submitted by ShaunDychko on Wed, 11/27/2019 - 10:07
I agree with your calculator. The two figures are the same quantities, expressed differently. If you try subtracting one from the other you'll find the answer is zero, as expected for numbers that are the same quantities. The 0.25x10^3 is something I just did in my head rather than using a calculator.
In reply to by C-Mak Breezy
The following is multiple choice question (with options) to answer.
What does pencil lead contain? | [
"aluminum",
"stable carbon",
"sunlight",
"mineral water"
] | B | pencil lead contains mineral graphite |
OpenBookQA | OpenBookQA-1623 | hydrology, mountains, rivers
Title: Why do rivers have 'wells' in mountains? Why/how can rivers have sources in places high above the sea level? The presence of water underground has nothing to do with sea level in mountainous country.
When rain fails on a mountain, or snow falls on a mountain and the snow eventually melts, the water from the rain or snow melt mostly travels downhill via rivers to the sea.
In getting to a river some of the water will fall on the ground. In places where the ground is covered by soil, water can travel through the soil via the pore spaces between the grains of soil. Similarly if porous rock, such as sandstone lies beneath the soil water can travel through the pores in the rock.
If a layer of impervious rock lies under the porous rock or soil, the water cannot move downwards, due to gravity, any further. This can lead to water accumulating in the soil or porous rock and saturating the soil or rock. In such situations an aquifer can form. The top of the saturated zone in an aquifer is called a water table.
The ground beneath a river is saturated and the surface of the river shows the water table exposed to atmosphere. Thus in mountainous regions the ground beneath rivers will be saturated and capable of supporting a well developed from the bank of a river.
The following is multiple choice question (with options) to answer.
If an area of land is sloped to the right and a body of water is on that slope, then the river will flow | [
"pollution",
"to the right",
"species",
"to the left"
] | B | the slope of the land causes a river to flow in a particular direction |
OpenBookQA | OpenBookQA-1624 | electromagnetism, electric-current, electronics, biophysics, electrical-engineering
Title: Why does an MRI machine or other EMP generating machine not damage humans, but it will fry computers? A sufficiently strong electromagnetic pulse can/will destroy smartphones and computers.
I know somebody who went into MRI machine and forgot a Visa credit card in his pocket. The card was toast and he had to get a new one. A mobile phone in an MRI probably wouldn't fare better.
But a big part of the human body itself is based on electric signals. The brain and nervous system, including the heart, works on electric signals. And those signals have to go to very precise places. There is an area of brain processing vision, another is responsible for speech, etc.
Also the heart function depends on precisely timed signals traveling very specific routes.
So it would seem that a trip to an MRI scan should totally fry anyone's possessing brain and heart.
Except it doesn't. An MRI scan is harmless (if you are not allergic to those injections they give).
Why?
And then there are those electromagnetic pulse devices they show in Hollywood movies. While totally trashing electronics of bad guys, fellow humans are always shown unharmed.
Again, why should the brain be different? A strong electromagnetic pulse can mess with your brain. See this video https://youtu.be/AXxhX0Pmm8w about transcrainial magnetic stimulation.
The MRI is just a big magnet and because the field is static there is no induced currents in the brain.
The magnetic strip on a credit card is erased by the MRI magnet because the field has aligned all the magnetic domains in the strip.
The following is multiple choice question (with options) to answer.
Magnetic media, such as TVs, computer monitors, credit cards and pacemakers can be damaged when exposed to | [
"neodymium",
"a paper clip",
"copper penny",
"metal nails"
] | A | metal is sometimes magnetic |
OpenBookQA | OpenBookQA-1625 | biochemistry, botany, plant-physiology, photosynthesis
What are typical characteristics of different plants in this regard? I.e., how do common species of plants manage their C consumption before (and after) the development of leaves? There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which store energy in their bonds. That energy is then released when required to power other reactions, which is how a plant lives and grows. C is also incorporated into all the organic molecules in the plant.
Plants require several things to live: CO2, light, water and minerals. If any of those things is missing for a sustained period, growth will suffer. Most molecules in a plant require some carbon, which comes originally from CO2, and also an assortment of other elements which come from the mineral nutrients in the soil. So the plant is completely reliant on minerals.
Most plants, before a leaf is established or roots develop, grow using energy and nutrients stored in the endosperm and cotyledons of the seed. I whipped up a rough diagram below. Cotyledons are primitive leaves inside the seed. The endosperm is a starchy tissue used only for storage of nutrients and energy. The radicle is the juvenile root. The embryo is the baby plant.
The following is multiple choice question (with options) to answer.
A plant needs to feed, so it | [
"spreads it's leaves",
"has a bite",
"spreads upside down",
"catches rabbits"
] | A | a leaf absorbs sunlight to perform photosynthesis |
OpenBookQA | OpenBookQA-1626 | light
More massive stars also "evolve" faster, because they burn their available fuel much faster. An "evolved" star is one which has finished fusing hydrogen in its core and moved on to "shell" burning around the core or burning heavier fuels in its core. Shell burning stars tend to be bigger and cooler than main sequence stars of the same mass.
$^{1}$ Increased magnetic activity can drastically increase the amount of light from a star at UV and X-ray wavelengths, by orders of magnitude. This is primarily a feature of comparatively low-mass stars (like the Sun or lower) and is driven by rapid rotation. Rapidly rotating (single) stars are young. This extra short wavelength light is not energetically important to the star, in that the vast majority of its radiation is still at visible and infrared wavelengths.
The following is multiple choice question (with options) to answer.
A star produces light energy and heat because it has a variety of | [
"moon rotation causing friction",
"light energy flowing to earth",
"reactions of nuclear form",
"global warming caused by co2"
] | C | a star is a source of light energy through nuclear reactions |
OpenBookQA | OpenBookQA-1627 | evolution, ecology, natural-selection, adaptation
Title: What are Some Classical Examples of Local Adaptation? Question
Can you please give a list of classical (textbook) examples of local adaptations?
How to answer
Examples don't necessarily need to include what evidence supports this specific example of local adaptation. A simple description of the local adaptation (e.g. coat colour changes from black on dark soil to white on light soil) and an brief explanation of the reason (e.g. because being nicely camouflaged prevents from predation from hawks) is enough.
I think a list of 10 or more such examples would be great.
Definition of local adaptation
Note that I define here local adaptation as differentially adapted subpopulation of a single species (with existing gene flow between subpopulations especially for sexually reproducing species).
Justification for the question
I found surprisingly complicated to find such list online. I think it could be a valuable post for many.
Examples
Examples of local adaptation (that you are free to add in your answer with a description) include beach mice camouflage, altitude adaptation in tibetans and peppered-moth camouflage. Adaptation is a change in a trait as a response to selection. As you ask for local adaptation I assume you want examples where sub-populations have either come under different selection and adapted differently, or cases where sub-populations have come under similar selection but not all have had the necessary genetic variation to evolve, i.e. selection has caused differentiation between sub-populations. Local adaptation can lead to varying degrees of divergence, so some for some examples it may be worth exploring speciation events. Here's some examples:
Galapagos Tortoises
There are two general shapes to the shell of tortoises on the Galapagos Islands. On islands with little low-lying vegetation the tortoises seem to have evolved long necks & limbs and different shell shapes which allow them to reach up more easily.
"The shell distortion and elongation of the limbs and neck in saddlebacks is probably an evolutionary compromise between the need for a small body size in dry conditions and a high vertical reach for dominance displays."
The following is multiple choice question (with options) to answer.
An example of migration would be | [
"robins flying from Minneapolis to Miami",
"geese flying to a park to bother the people there",
"bison that belong to a farmer being moved to a different pasture",
"mice running from a fox"
] | A | migration is when animals move themselves from a cooler climate to a warmer climate for the winter |
OpenBookQA | OpenBookQA-1628 | meteorology, atmosphere, wind, air-currents
Title: Where does wind come from? Wind is (according to Wikipedia) the flow of gases on a large scale.On the surface of the Earth, wind consists of the bulk movement of air.
What forces would cause such a mass movement of air? Wind is caused by pressure differences. Think of a balloon full of air; poke a hole in it and the air comes out. Why? Because the pressure in the balloon is higher than outside, and so to regain equal pressure, mass moves and that is the wind.
There is a bit more to this in the atmosphere as the Earth rotates and near the surface friction also plays a role. The equation of motion is the Navier-Stokes and in vector form in Cartesian space is:
$$\dfrac{\partial\mathbf u}{\partial t} = - \mathbf u \cdot \nabla \mathbf u -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F$$
In this equation, $\mathbf u$ is the vector wind, $(\mathbf u \cdot \nabla)$ is the advection operator, $\rho$ is density, $\mathbf \Omega$ is the vector rotation of the Earth, $\mathbf g$ is effective gravity and $\mathbf F$ is friction.
The LHS is the time rate of change of the wind at a point in space (as opposed to following the parcel). The RHS represent a number of factors that produce a change in the wind. From left to right:
Advection of momentum (non-linear)
Pressure gradient force (this is wind blowing from high to low pressure)
Coriolis force (this turns wind to the right in the NH and left in the SH and causes the wind to flow parallel to isobars)
gravity (provides hydrostatic balance with the PGF in the vertical)
Friction (in the boundary layer you may see this as $\nu\nabla^2\mathbf u$)
The following is multiple choice question (with options) to answer.
What is the source of air? | [
"humans",
"space",
"chemistry",
"nature"
] | D | nature is the source of natural resources |
OpenBookQA | OpenBookQA-1629 | amateur-observing, binoculars
Title: How do I prevent or reduce shake when observing with binoculars? I have some 16 x 50 binoculars that my parents bought me years ago. Recently I have tried to do some basic lunar and planetary observations with them but I am seriously struggling with shaking. This was most noticeable tonight while attempting to observe the ISS.
While I accept that keeping the image of a moving target stable is going to be next to impossible, I would like to know how I could reduce my shaking while observing the moon and other objects.
Is anyone able to provide some simple techniques to reduce shaking? Don't hold the binoculars in your hands. Humans are made of meat. wobbly wobbly meat. There's apparently devices that let you mount binoculars on tripods - (this google search would be a start). Those and a tripod would probably be helpful in decreasing shake.
I suppose it would affect mobility a little but that's a tradeoff.
The following is multiple choice question (with options) to answer.
A woman needs to check something with binoculars, so it is likely | [
"very near",
"inside the room",
"a ways away",
"in outer space"
] | C | binoculars are used for observing distant objects |
OpenBookQA | OpenBookQA-1630 | agriculture
The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of gruel and porridge rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of pearl barley and groats and oats in the form of oatmeal. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When Samuel Johnson wrote his dictionary, he famously defined oats as: "A grain which in England is generally given to horses, but in Scotland supports the people." A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.
In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area, Ph.D. thesis, University of Helsinki, 2007 (online)
The following is multiple choice question (with options) to answer.
Compared to an area with farmland, an area with housing developments has more | [
"crops",
"wilderness",
"light pollution",
"animals"
] | C | as distance to a city decreases , the amount of light pollution will increase |
OpenBookQA | OpenBookQA-1631 | ecology
Title: Do invasive species cause long-term damage to ecosystems they invade? Growing up in the U.S., I was warned at various times of the dire consequences of a variety of introduced pests (usually insects).
Japanese beetles, gypsy moths, and most recently the brown marmorated stink bug are all introduced pests that, at various times, were described as serious threats to our ecology.
These threats aren't confined to arthropods, either. The giant African land snail is causing a stir in Florida (indeed, Florida seems to suffer from an excessive variety of introduced species.
"Lack of native predators" is frequently cited as the primary reason many invasive species are considered such a risk to the ecology.
I understand that these introduced species can place tremendous pressure on native species that fill similar ecological niches, and may even push these species out of the region due to competition for food and habitat. However, do the overall ecologies that these species are introduced to adjust over long periods of time?
The numbers of Japanese beetles and gypsy moths don't seem anywhere as high as when I was a child. Has the ecosystem adjusted, or has the overpopulation self-corrected as the species ran low on food through over-consumption? Or are the populations still just as problematic now as they were 30 years ago, and I just am not seeing the bigger picture?
What is the long-term impact that we've seen from invasive, introduced species? Is there a significant difference on the long-term impact between introduced flora, arthropods, or mammals? The answer really depends on how you think of invasive. One extreme answer is to say that all things are relative, and that the concepts of local and invasive are all relative. This matters to a certain extent because ecologists draw a fuzzy line between invasive and naturalized. You could start with some basic species that we all think of as either good, local, or neutral. Take the earthworm. Most people think of it as a common native species, but the earthworm is actually an invasive species that has radically changed much of North America that came over with the Europeans. Similarly, brown trout are also invasive, coming to the US in the 1800's.
The following is multiple choice question (with options) to answer.
What does planting native plants has a positive impact on? | [
"markets",
"territory",
"winds",
"economies"
] | B | planting native plants has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-1632 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
In order for a fox to catch a chicken it must | [
"order Kentucky Fried Chicken",
"always move exponentially quicker",
"jump on it from a high tree",
"swim out to it"
] | B | some predators move quickly to catch prey |
OpenBookQA | OpenBookQA-1633 | oceanography, sea-level, tides
Title: Why do high tides vary month to month? I've noticed that some ‘highest‘ high tides in one month are bigger than the highest high-tide of previous months. Why is this so? The dynamics of the tides are quite complex. The main idea is that gravity from the Moon and the Sun affect water (and everything else) on Earth. The issue is that there are several motions that alter the distance between the 3 systems and those motions cause interactions between the different frequencies involved. The Equilibrium Theory of Tides separates the different effects into a set of constituents by conducting a harmonic analysis. The relevant periods are:
the lunar day (period of lunar rotation), 24.84 mean solar hours.
the sidereal month (period of lunar declination), 27.32 mean solar days.
the tropical year (period of solar declination), 365.24 mean solar days.
the period of the lunar perigee, 8.85 years (1 year = 365.2421988 days).
the period of the lunar node, 18.61 years.
the period of the solar perihelion, 20940 years.
The explanation of each constituent can be rather complex (some examples in this other answer). The different amplitudes in a day and the spring-neap cycle are related to the combination of the main lunar and solar effects.
The differences in high/low tide from month to month are related to the next two main frequencies of oscillation. Mainly, the variations in Earth-Sun distance associated occurring in a period of tropical year. The lunar distance also contributes to these differences, but its cycle is much longer (~9 years). Also, the spring-neap cycle (with a frequency of half a lunar month ~13.5 days) will occur at different times of the month and can lead to differences in tidal amplitude if you compare the tides measured the same day of consecutive months.
(Source www.niwa.co.nz)
The following is multiple choice question (with options) to answer.
High tide is a stage in the | [
"food chain of the monarch butterfly",
"moon tugging on saltwater",
"timeline of all humanity",
"life cycle of land mammals"
] | B | high tide is a stage in the tide cycle process |
OpenBookQA | OpenBookQA-1634 | electricity, electric-circuits, electrons
Title: Do electrons coming out of a lightbulb (and going back into the circuit) slow down? Do electrons coming out of a lightbulb (and going back into the circuit) slow down?
The electrons enter the light bulb filament with relatively high kinetic energies. As they travel through the filament they collide with metal atoms transferring much of their kinetic energy to the metal. This energy raises the temperature of the metal. The metal in turn radiates this energy as electromagnetic waves, many in the visible spectrum.(Source 1)
and
Each light bulb results in a loss of electric potential for the charge. This loss in electric potential corresponds to a loss of energy as the electrical energy is transformed by the light bulb into light energy and thermal energy. (Source 2)
The following is multiple choice question (with options) to answer.
A light bulb turns on when it receives energy from | [
"a cable",
"an oven",
"gasoline",
"a person"
] | A | when electricity flows to a light bulb , the light bulb will come on |
OpenBookQA | OpenBookQA-1635 | evolution, botany, photosynthesis, speculative, chloroplasts
Title: Why do plants have green leaves and not red? I know plants are green due to chlorophyll.
Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light has more energy than red light.
Is there no alternative to chlorophyll? Or is it something else? Surely it would be even more beneficial for plants to be black instead of red or green, from an energy absorption point of view. And Solar cells are indeed pretty dark.
But, as Rory indicated, higher energy photons will only produce heat. This is because the chemical reactions powered by photosynthesis require only a certain amount of energy, and any excessive amount delivered by higher-energy photons cannot be simply used for another reaction1 but will yield heat. I don't know how much trouble that actually causes, but there is another point:
As explained, what determines the efficiency of solar energy conversion is not the energy per photon, but the amount of photons available. So you should take a look at the sunlight spectrum:
The following is multiple choice question (with options) to answer.
What does a leaf need to do to absorb the most sunlight that it can? | [
"Hide in shade",
"Remain small",
"Grow very large",
"Change colors"
] | C | as the size of a leaf increases , the amount of sunlight absorbed by that leaf will increase |
OpenBookQA | OpenBookQA-1636 | simulation, performance, many-body-systems
Note: This bound diverges when $B/J\to \infty$, while the physical information propagation speed stays finite. We can get rid of this problem by using the method in Sec. VI of Ref1. The result is $v_{\text{LR}}\leq 4\mathcal{X}_0 J$ in this limit, where $\mathcal{X}_y$ is defined as the solution to the equation $x\mathrm{arcsinh}(x)=\sqrt{x^2+1}+y$.
The following is multiple choice question (with options) to answer.
Molecular bounds are broken by | [
"ice",
"combining vulotile ingredients",
"soap and water",
"force"
] | B | chemical reactions cause chemical change |
OpenBookQA | OpenBookQA-1637 | evolution, taxonomy, ornithology
Title: Birds and Dinosaurs This came up in an argument with some friends. I know that birds are direct descendants of dinosaurs, shown pretty clearly through the fossil record. However, is it proper to say that birds are dinosaurs, or is there an actual distinction? I bet you'll be interested about the concept monophyly. Any human-made group of species (or taxon) like birds dinosaurs, primate, bacteria, angiosperm, reptiles, … are either monophyletic, polyphyletic or paraphyletic. This picture explain the concept When the taxon is monophyletic it is called a clade.
Monophyletic taxon are those groups of species that can be considered to be objective in the sense that it represents a group of species where each species in the taxon is more related (in terms of time to common ancestor, not according to their genetic similarity) to any other species within the same taxon than to any other species outside this taxon. This is obviously not the case for paraphyletic or polyphyletic taxon.
Typically, we do not consider a parrot or a deer to be reptiles. Therefore, the ususal understanding of "reptiles" makes this taxon paraphyletic. Now, one should not confound the common understanding (what is a reptile in our everyday life) with the strict definition of the taxon Reptilia, which is a monophyletic taxon (or a clade in other words). Probably the best source for exploring the tree of life is tolweb.org. Here, you will find the clade Reptilia (who include birds, snakes, turtles and lizards). Note: Mammals are within the Reptiliomorpha, not the Reptilia.
It is exactly the same issue with the dinosaurs. When we talk about dinosaurs in our everyday life we do not mean birds. But there is a clade called Dinosauria, which include both dinosaurs and birds.
In short, I would say that a bird is a Dinosauria (monophyletic taxon) but is not a dinosaur (paraphyletic taxon). But this little play on word is not a scientific issue but an issue of english usage.
You will also find in this post an introduction to phylogeny
The following is multiple choice question (with options) to answer.
The thing that is shared between birds, people, snakes, and sharks is that they | [
"defecate",
"eat beans",
"pray",
"lay eggs"
] | A | all living things eliminate waste |
OpenBookQA | OpenBookQA-1638 | climate-change, climate
In this case, as it is an area that it is almost constantly cloudy with high humidity, temperature is varying just a little bit, and except the first day of the period, it seems that there is no relationship. In fact, on the second day there was a storm (I am living now at Singapore) and it is reflected in a quick change in temperature (both) and solar radiation.
Conclusion: It is not as simple as it seems.
Hope it helps!
The following is multiple choice question (with options) to answer.
A cat is laying outdoors in the sunlight. Suddenly, a large, dark cloud blocks the sun and the temperature drops several degrees. The cat's physical reaction to this abrupt change will most likely be | [
"finding someone to dye them pink",
"involuntary body tremors and shudders",
"creating a new telephone system",
"hopping a plane to warmer climates"
] | B | shivering is when an animal creates heat by shaking to keep the body warm |
OpenBookQA | OpenBookQA-1639 | python, game, role-playing-game
class Bag():
def __init__(self, inventory):
self.inventory = inventory
def add_to_inv(self, key, location):
self.inventory.append(location.room.roominv[key])
del location.room.roominv[key]
def check_inv(self):
for item in list(self.inventory):
print("Your bag contains:", item.name)
world = {}
world['introd'] = Room('introd', "You are in a forest, you can hear wildlife all around you. There seems to be a clearing in the distance.", {'n': "clearing"}, {"Search the ground", "Go North"}, {'Sword': Sword}, None, False)
world['clearing'] = Room('clearing', "You are in a clearing surrounded by forest. Sunlight is streaming in, illuminating a bright white flower in the center of the clearing. \
To the South is the way you entered the forest. A well worn path goes to the East. In the distance a harp can be heard.", {'s': "introd", 'e': "forest path"}, {"Take flower", "Go south", "Go East"}, {'Flower': Flower}, None, False)
world['forest path'] = Room('forest path', "You begin walking down a well beaten path. The sounds of the forest surround you. Ahead you can see a fork in the road branching to the South and East.\
You can smell smoke coming from the South, and can hear a stream to the East", {'s': "cottage", 'e': "stream", 'w': "clearing"}, {"Go South", "Go East", "Go West"}, {'Stick': Stick}, None, False)
The following is multiple choice question (with options) to answer.
A person is going to the woods to bag fresh venison. This person is | [
"fishing",
"gardening",
"stalking",
"building"
] | C | hunting means humans kill animals in the wild |
OpenBookQA | OpenBookQA-1640 | Now find the time Rick spends running.
$\displaystyle t_{r,R}=\frac{D}{2v_r}$
Now just add the two times up and you’re done.
$\displaystyle t_R=\frac{D}{2v_w}+\frac{D}{2v_r}=\frac{D}{2v_wv_r}\left(v_w+v_r\right)$
#### PART B. Find Rick’s average speed for covering the distance D.
You were given the total distance and have calculated the total time. Recall that average speed is equal to the total distance traveled divided by the amount of time it took to travel this distance.
$\displaystyle v_{ave,\:R}=\frac{2v_rv_w}{v_w+v_r}$
#### PART C. How long does it take Tim to cover the distance?
Tim walks at speed $\displaystyle v_w$ half the time and runs at speed $\displaystyle v_r$ for the other half.
$\displaystyle v_{ave,\:T}=\frac{v_w+v_r}{2}$
The time is just the distance divided by the average speed.
$\displaystyle t_T=\frac{D}{\frac{v_w+v_r}{2}}=\frac{2D}{v_r+v_w}$
#### PART D. Who covers the distance D more quickly?
Imagine that both Rick and Tim do all of their walking before they start to run. Rick will start running when he has covered half of the total distance. When Tim reaches half of the total distance, will he already have started running?
#### PART E. In terms of given quantities, by what amount of time, Δt, does Tim beat Rick?
$\displaystyle \Delta t=\frac{D\left(v_w-v_r\right)^2}{2v_rv_w\left(v_r-v_w\right)}$
This is just simple subtraction between the two computed times.
The following is multiple choice question (with options) to answer.
A person is going to run around a circle and wants to use a stopwatch in order to _____ time | [
"require",
"enjoy",
"find",
"mark"
] | D | a stopwatch is used to measure time |
OpenBookQA | OpenBookQA-1641 | meteorology, tropical-cyclone, lightning, mesoscale-meteorology
The answer for Harvey is probably all of the above. Places like Houston were first in the further extents of the storm the early days and so were able to see the more typical fluctuations of strong rising updrafts and stronger sinking downdrafts more typical of normal thunderstorm convection and the outer rainbands in tropical cyclones. And then had a storm seeing important structural changes by the time it moved nearer Houston (as marked by the significant tornado outbreak)
And areas nearer the center of Harvey saw rapid intensification (indicating there was more instability nearer the storm center still), eyewall replacement, plus the usual frictional convergence at landfall all favoring a bit of an uptick in lightning. Harvey may well have not been too different from most landfalling hurricanes, but had the benefit of rapid intensification to help lightning production some... and it was dark so it could be seen more!
The following is multiple choice question (with options) to answer.
After a week of storms, the nearby lake now has more | [
"fish",
"birds",
"liquid",
"plants"
] | C | storms cause bodies of water to increase amount of water they contain |
OpenBookQA | OpenBookQA-1642 | species-identification, zoology
Title: What animal does this skull belong to? This skull was found in Greece, about 40 years ago, possibly in the island of Euboea (there is uncertainty about the area it was found).
The length from nose to the end of horns is 67 cm. The skull's length without the horns is 42 cm. Just for reference, the floor tiles in the pictures have a side of 33cm.
What could this animal be? It does not have to be native to Greece, even though a native animal would be more probable.
Update:
The size of the skull points to an animal larger than a goat. It looks more like an antelope, a gazelle, or even a deer. Only deers are native to Greece, however the horns look nothing like deer.
I believe the horns are the key to unlock this mystery. Its definitely a bovid, most likely an african antelope specifically a Hartebeest or Alcelaphus buselaphus . There are several sub-species but those horns are a dead giveaway. The the horn do vary a bit by sub-species. The Neumann's or Tora hartebeest might be your best bet but I can't be 100% sure. They are all popular hunting trophies since forever and are even kept in some european game reserves so it is not that hard to find there skulls in private hands. Search "hartebeest skull" and you'll find a million of them so you can try for a more exact match.
The following is multiple choice question (with options) to answer.
A dead deer was found partially eaten in a forest. How could it have been caught? | [
"It was caught by appendages on the feet of a feline",
"A raccoon jumped on the deer's back and killed and ate it",
"It was caught by a horse's mouth",
"It was shot by a bear"
] | A | claws are used to catch prey by some predators |
OpenBookQA | OpenBookQA-1643 | geothermal-heat
Title: What Keeps the Earth Cooking? If radioactive decay supplies only about half the Earth’s heat, what are the remaining sources of heat?
If radioactive decay supplies only about half the Earth’s heat, what are the remaining sources of heat?
Mostly it is residual heat energy from when the Earth was very young. The biggest source came from the kinetic energy of all the bodies, big and small, that collided to form the Earth being converted to heat. The differentiation of the Earth added even more heat energy to the Earth.
In addition to radioactive decay, the on-going freezing of the outer core material onto to the inner core adds a bit more heat to the system, but neither one compensates for heat transported through the mantle and crust and then out into space. Note that this heating from below is but a tiny portion of the overall energy budget for the Earth's surface.
Even the Earth's surface was very hot shortly after the formation and differentiation of the Earth. While the surface cooled quickly (geologically speaking), the interior has not. The key reason is that 2,890 km of rock makes for a fairly thick blanket.
The following is multiple choice question (with options) to answer.
Which of these is a source of heat? | [
"ice cubes",
"coffee",
"Popsicles",
"ice cream"
] | B | a hot substance is a source of heat |
OpenBookQA | OpenBookQA-1644 | food-chemistry
popcorn (kernels)
honey (jar of)
sugar (most forms)
alcohol (spirits like vodka, whiskey)
dried beans, dried lentils
I would not be planning to eat any of these stored for 25 years myself. And in general I'd suggest testing the items before trying them after 25 years or more (if you feel you must).
I would not expect cans or glass or plastic bottles of soda to be in good shape after anything like 25 years. The plastic might not survive without degrading. The can and plastic might react with the liquid over that timescale and the glass would survive but I'd be less optimistic about a sugar laced chemical soup like soda or cola not undergoing some changes. Hard to say.
If you want more info on this try this website.
Will it be ok to drink it, if it won't explode?
I would not try it. At best it soda would be flat and possibly not taste the same (chemical changes over that timescale ?) and at worst it could actually be harmful.
Exploding seems very unlikely.
Also, what about Snickers or a hamburger in a ziploc package with air sucked out of it with vacuum cleaner?
Air isn't the issue. There are bacteria that will happily live (and increase in numbers) on what's in the food. Well, it is food, after all. There are bacteria that will survive refrigeration as well. Over the timescale you're talking about I'd say it's all bets are off territory.
So: will Snickers, Hamburger in a ziploc, Bottle (or can) of Cola, all not opened, go crazy in 25 years? In 50 years?
All of those could be dangerous over such a long time period, IMO. At the very least they'd taste bad and at worst they'd kill you if you consumed them.
If so, can they go out of their packages and ruin the contents of the time capsule? If not, will it be safe to consume one of them?
Depends on the packaging. Glass would last indefinitely baring physical force or extreme of hot and cold (which might possibly cause fatigue cracking). The other wrappers would last pretty well (structurally), but 25 years is way past their design intentions. It would be a dice throw.
The following is multiple choice question (with options) to answer.
A metal sticker remains on a fridge because of | [
"vibrations in the surface of the fridge door",
"a force that pulls two objects together",
"magic that Juggaloes are unable to explain",
"the entropy of the universe"
] | B | magnetic attraction pulls two objects together |
OpenBookQA | OpenBookQA-1645 | sexual-reproduction
So when it's not maintained -- when there's no selection pressure on two populations -- inevitably there will be genetic drift that will randomly disrupt this fine-tuned system. If a population of, say, voles is isolated on an island, they will continue to have pressure to be able to interbreed with other voles on the island, but if they can't interbreed with those on the mainland there won't be any consequences, and so over long enough time they'll drift and lose that ability -- just as many apes, not suffering any consequences from not synthesizing vitamin C, gradually lost that ability from random drift.
There's another side to it. Two populations in the same location may be positively selected to not be able to interbreed. Think about two groups of finches, one with small fine beaks that eat tiny seeds deep inside pine cones, and one with heavy beaks that crush and eat thick-shelled nuts. They each do fine, but they can interbreed and produce offspring that have intermediate beaks -- too thick to reach the fine seeds that one parent eats, but too delicate to crush the nuts that the other parent eats. Those intermediate offspring will die off, and both parents will have wasted their resources raising them. Both parents would be better off not breeding with each other, but only breeding with their own kind to produce specialized and efficient offspring. There is now selection pressure on the birds to recognize their own kind (perhaps through songs or mating displays) and ultimately to be inter-sterile, so they never waste resources on the un-fit offspring. There's a gradation of separation over time, in which the different populations become more and more distinct. Eventually, at some arbitrary point, humans start calling them "species", but that's just us, not biology.
"Species" is an important concept, but it's not special in evolution; speciation is just one aspect of natural selection, there's nothing magical about it.
The following is multiple choice question (with options) to answer.
What happens when man moves into new environment but reproduction ceases to happen? | [
"native species go wild",
"native species grow large",
"native species loses dwindle",
"native species thrive more"
] | C | if all members of a species cannot produce offspring then that species will likely become extinct |
OpenBookQA | OpenBookQA-1646 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
Large eared, small mammal preferred by bald eagles as prey | [
"hare",
"dog",
"hawk",
"bear"
] | A | eagles eat rabbits |
OpenBookQA | OpenBookQA-1647 | html, css
<body>
<div class="fruits">
<p>Highest Fruit Score: <span class="score">83</span></p>
<ol>
<li class="gold"><img alt="banana" src="//i.imgur.com/uBDRMVu.png"> <span class="score">83</span></li>
<li class="silver"><img alt="apple" src="//i.imgur.com/LGuyqx6.png"> <span class="score">65</span></li>
<li class="bronze"><img alt="raspberry" src="//i.imgur.com/eOsWQe5.png"> <span class="score">34</span></li>
</ol>
</div>
</body>
</html>
The following is multiple choice question (with options) to answer.
The pips of a pumpkin are most commonly | [
"flow to space",
"fueling trucks",
"seasoned and devoured",
"drowned alive"
] | C | a pumpkin contains seeds |
OpenBookQA | OpenBookQA-1648 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
A body needs fiber to make healthy bowel movements and this can be absorbed by consuming | [
"water",
"cheese",
"eggs",
"broccoli"
] | D | plants are a source of fibers |
OpenBookQA | OpenBookQA-1649 | python, object-oriented, programming-challenge, python-2.x
class Vehicle():
MOVEMENT = {'N': (0, 1), 'E': (1, 0), 'S': (0, -1), 'W':(-1, 0)}
def __init__(self, x, y, facing, grid, obstacle):
self.x = x
self.y = y
self.facing = Directions(facing)
self.grid_width, self.grid_height = grid
self.obstacle = obstacle
@property
def direction(self):
return self.facing.current
@property
def position(self):
return (self.x, self.y)
def parse_commands(self, commands):
action = {
'L': self.facing.previous,
'R': self.facing.next,
'M': self.move,
}
for command in commands:
action[command]()
def move(self):
offset_x, offset_y = self.MOVEMENT[self.facing.current]
x = self.x + offset_x
y = self.y + offset_y
if (x, y) != self.obstacle and 0 <= x <= self.grid_width and 0 <= y <= self.grid_height:
self.x = x
self.y = y
def setup_and_move_vehicule(grid, obstacle):
x, y, facing = raw_input().split()
vehicule = Vehicule(int(x), int(y), facing, grid, obstacle)
vehicule.parse_commands(raw_input().strip())
return vehicule.position, vehicule.direction
def main():
grid = map(int, raw_input().split())
v1_pos, v1_dir = setup_and_move_vehicule(grid, None)
v2_pos, v2_dir = setup_and_move_vehicule(grid, v1_pos)
print v1_pos[0], v1_pos[1], v1_dir
print v2_pos[0], v2_pos[1], v2_dir
The following is multiple choice question (with options) to answer.
A person wants to take a a mode of transportation out that has two wheels so they will need to | [
"drive",
"bus",
"cycle",
"run"
] | C | a human can pedal a bicycle |
OpenBookQA | OpenBookQA-1650 | organic-chemistry, experimental-chemistry, surface-chemistry
Title: Three general questions in silanization of a glass surface For silanization, I put a glass slide horizontally and pour the silan solution on it to cover the glass surface. Then I leave it for a specific time and then wash with water and acetone.
I have three questions:
Is this method correct or I should necessarily deep coat the glass plate into a container of silan solution (because in the 2nd method, there are larger number of available agents than can react with glass or have better accessibility to the glass surface)?
How durable is the silanized glass? i.e. after silanization, when I want to clean the glass surface from reaction products, can I rub something onto the surface to help clean it better or the treated layer of glass might be damaged? (rubbing with cleanex, etc)
For getting maximum hydrophobicity, can I use Octadecyltrichlorosilane>90% directly on glass surface (for how much time?) or I should dilute it?
Is this method correct or I should necessarily deep coat the glass plate into a container of silan solution (because in the 2nd method, there are larger number of available agents than can react with glass or have better accessibility to the glass surface)?
Your method is fine, anything method that covers the surface with solution will work.
How durable is the silanized glass? i.e. after silanization, when I want to clean the glass surface from reaction products, can I rub something onto the surface to help clean it better or the treated layer of glass might be damaged? (rubbing with cleanex, etc)
In my experience hydrophobic coatings are durable, but will wear due the the small surface thickness. My recommendation is to use rinsing only, if you can and use abrasive cleaning when you have to.
For getting maximum hydrophobicity, can I use Octadecyltrichlorosilane>90% directly on glass surface (for how much time?) or I should dilute it?
The following is multiple choice question (with options) to answer.
Combining resin and glass mat with a catalyst will result in | [
"broken glass",
"a mess",
"toxic fumes",
"fiberglass"
] | D | chemical reactions cause different substances to form |
OpenBookQA | OpenBookQA-1651 | power, battery, circuit
Regarding your bonus points, the other devices you've listed aren't power storage devices. They can run indefinitely, provided they're powered. A solar cell doesn't hold a charge, so it can't run anything for any amount of time if there's no sun. If there is sun, it can supply its rated power as long as the sun is out. Note again though rated power - you can't run a 5W robot on a 1W solar cell. Same applies for all other power supplies. The are power supplies, not power reserves like a battery.
The following is multiple choice question (with options) to answer.
You may be able to use solar energy to power | [
"a garden",
"a bike",
"a coffee grinder",
"water pipes"
] | C | solar energy is a renewable resource |
OpenBookQA | OpenBookQA-1652 | pain, death
Title: Normal death experience Consider a natural cause of death (no car accidents etc) -
Is it true that death is generally preceded by suffering? In other words, are we destined to experience the most severe suffering we could not ever imagine, that will ultimately end with death?
If this is true, is it true for all living things? No and no.
I'm not sure what is a "natural cause" in this context, but if it's cardiac arrest caused by age-related dystrophy of the cardiac muscles, then no, there is no suffering, at least not universally: Since age-related dystrophy hits all parts of the body, it's likely preceded by increasing amounts of bed rest, leading to quietly drifting off into the great sleep.
Of course, if you add on other natural causes like age-related diseases or being eaten by predators, the suffering can be great indeed, or not: A tiger will sneak up on you and crush your skull without you ever knowing what happened.
Adding on further causes still, like dehydration or hunger, and the suffering is back.
But is suffering a universal fixture of death? Emphatically no.
As for the "all living things" part of the question, the answer isn't just "no"; it's "that's nonsensical".
By individual count, practically no life is complex enough for suffering to be a relevant concept.
I don't have an exact number for you, because how would I get one, but at a rough estimate, bacteria, algae and archea constitute 100% of all individual life forms by count, and suffering is not a concept that makes sense for them.
If we ignore simple life, even among complex life there is so much variety of capabilities that basically nothing universal exists.
The following is multiple choice question (with options) to answer.
What is present in death at the end of the life cycle | [
"spirits",
"Bacteria",
"God",
"Food"
] | B | decomposition is when a decomposer breaks down dead organisms |
OpenBookQA | OpenBookQA-1653 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
A sea creature can defend itself easily by using | [
"hostile smiles",
"malicious kisses",
"toxic pricks",
"noxious caresses"
] | C | poisonous darts are used for defense by sea anemones |
OpenBookQA | OpenBookQA-1654 | humidity, air-pollution
Title: Does usual city pollution have effects on relative humidity? I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity? By way of reference, "humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature".
From the information you have supplied in your comments. There are waters in Bucharest and forests in the suburbs, but no waters or forests where the country house is located.
From your information, Bucharest has a number of sources of atmospheric water vapour, the river that flows through it (evaporation of water) and the forests in the suburbs (transpiration of water). Additionally, motor vehicle exhausts will increase the humidity as water vapour is one of the products of the combustion of hydrocarbons.
The warmer the air, the greater its capacity to hold moisture. Cities tend to be warmer than rural areas due to the heat island effect, which is the result of modifying land surfaces and the generation of waste heat.
Humidity in the rural location will arise from evaporation of water in the soil and transpiration from crops or grasses. Such transpiration will produce less water vapour than forests. Additionally, the rural location will have significantly fewer cars producing water vapour in their exhausts. Consequently, the rural location will be less humid than the city.
The reason why Bucharest is more humid that the rural location has more to do with the greater availability and vaporization of water in Bucharest and the temperature of Bucharest than the amount of pollution in Bucharest.
The following is multiple choice question (with options) to answer.
Another source of pollution may be | [
"throwing things in the ocean",
"buying a new solar panel",
"biking instead of driving the car",
"using old food as compost for the plants"
] | A | burning gasoline is a source of pollution |
OpenBookQA | OpenBookQA-1655 | zoology, ethology
Title: Is there a term for tool use in animals? Is there a technical/scientific term that scientists use to refer to tool making abilities found in certain types of animals?
Reference http://en.wikipedia.org/wiki/Animal_cognition#Tool_and_weapon_use Having read this article on tool use in Chimpanzees in full, I am inclined to say that if such a term existed then either the article itself or the titles of any of the 30 articles referenced would have included it.
Searching a couple of online biological dictionaries and ethology sites hasn't yielded anything either, therefore until someone else points out that I'm missing the obvious I'd say you're free to coin the term yourself!
The following is multiple choice question (with options) to answer.
Which of the following would be an example of tool use in the animal kingdom? | [
"a wolf using its sense of smell to track down prey",
"a crow displacing water with rocks to get good",
"a giant whale filtering plankton from water",
"An anteater using its long tongue to catch ants"
] | B | An example of using tools is a chimpanzee digging for insects with a stick |
OpenBookQA | OpenBookQA-1656 | the-sun, orbit, planet, earth
Is the spiraling movement caused by sun movement (on its path shown
above) where the sun is dragging the earth (and other planets)?
No, the Sun's and the Earth's mutual gravity cause the Earth to rotate around the Sun. The Milky Way's gravity causes our Solar System to revolve around the galactic center. The Sun and the Earth are on the same plane and moving through the galaxy together. The Earth would still rotate around the center of the Milky Way if the Sun magically disappeared.
Does the earth go in front of the sun then back, then fourth and back
like it is shown on the video? I see both the sun and earth racing
with each overtaking the other over and over. Is this assumption true?
In this manner, would earth, at one point in time, be closer to the
destination where the solar system is heading (I think they call the
destination Vega) than the sun?
If you consider a plane tangent to the Sun's velocity vector, then the Earth will pass across that plane twice per year, appearing "in front of" and then "behind" the Sun. This is simply a geometric result since the Earth and Sun share another plane. I wouldn't call any future position of the Solar System a "destination" without evidence the Solar System was sentient, but I am not a philosopher.
I am working on a poetry piece. If I mention that earth and sun are
locked in a never ending race with each taking the lead (earth moving
in front of the sun's path / winning) and earth actually dropping out
of the race (spiraling/moving out the race and falling behind), that
they are destined to never meet (collide), would I be correct?
We haven't ruled out the possibility that the Sun may someday envelope the Earth: What will "the Earth being consumed by the Sun" look like?. Also, the Earth isn't likely to leave its orbit before that time, but the Solar System is chaotic on long time scales. However, your poem would be consistent with current models, and we (humans) don't conclusively know how the Solar System will end. So my two cents is that your poem doesn't contradict modern astronomy. Besides, what's the use of a poetic license if you don't use it?
The following is multiple choice question (with options) to answer.
the Earth rotating on its axis causes stars to appear to move across the sky when? | [
"sleeping hours",
"sun time",
"day",
"daytime"
] | A | the Earth rotating on its axis causes stars to appear to move across the sky at night |
OpenBookQA | OpenBookQA-1657 | electrostatics
Title: Does the potential of two spheres become equal when we connect them? I was reading a chapter on capacitors where it was asked whether given two spheres, each carrying a charge $q$ and of radius $r$ and $2r$, will charge flow between them?
I assume the answer should be no as both are having the same charge (that is what I learned in electrostatics that charge redistributes in such a way that charges become equal). But the book says that charge will flow. My friend told me that their potential will become equal. But why will their potential become equal (if it does)? Whenever there is a Potential difference, there would be a flow if there is a conductor in place (like your case, where metal objects are in touch)
The flow will continue until the potential difference does not exist any more.
This is like water always flowing from a higher to lower altitude if it can. So across a metal, you will always have the same potential. Based on that you can calculate the charge for them.
It means, the charge in each sphere should be as much that the Potential on the surface (where they are in contact) would be equal for both objects. You also know the total charge in the system.This should be enough to solve the problem.
We know potential on surface of sphere equals kQ/R , so we have kQ1/R1 = kQ2/R2 or Q1/R2=Q2/R2. Also we know R1 is twice R2 and we know that Q1+Q2 equals 3. The rest is just simple math to figure out Q1 and Q2.
The following is multiple choice question (with options) to answer.
If two objects have the same charge then what will they do to eachother? | [
"repel attackers",
"approach",
"pull",
"push away"
] | D | if two objects have the same charge then those two materials will repel each other |
OpenBookQA | OpenBookQA-1658 | statistical-mechanics, atmospheric-science, density
A limnic eruption, also referred to as a lake overturn, is a rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud that can suffocate wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, or explosions can be a trigger for such phenomenon. Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes.
Picture 1: one of a number of cattle killed by a limnic eruption at Lake Nyos, Cameroon.
We can occasionally prevent the buildup of carbon dioxide by degassing the body of water.
Picture 2: a siphon used by French scientists to de-gas Lake Nyos. The carbon dioxide emerges from its deposits and bubbles into the water, floating to the top.
The following is multiple choice question (with options) to answer.
A lake is unsafe for swimming because it is a bit below some farmlands that use | [
"pesticides",
"water",
"soil",
"solar energy"
] | A | runoff contains pesticides from cropland |
OpenBookQA | OpenBookQA-1659 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
Some animals may use coloration for | [
"eating",
"smells",
"love",
"protection"
] | D | coloration is used to find a mate by some animals |
OpenBookQA | OpenBookQA-1660 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
A moth can adjust its | [
"age",
"ancestry",
"shape",
"genus"
] | C | a moth undergoes metamorphosis |
OpenBookQA | OpenBookQA-1661 | genetics, botany, twins
In a number of varieties, two and sometimes three megaspores were functional, giving rise to several embryo sacs. On fertilization, embryos develop in these, causing the phenomenon of pseudopolyembryony.
Therefore this source seems to agree with the first.
However, a more recent paper Martínez-Gómez, P., & Gradziel, T. M. (2003). Sexual polyembryony in almond. Sexual plant reproduction, 16(3), 135-139., focused on almonds, suggests that certain almond cultivars are prone to true polyembryony, though it seems like the additional seeds are often a bit stunted and have high mortality. They also reference a paper purporting to mention polyembryony in peach, Toyama, T. K. (1974). Haploidy in peach. HortScience, 9, 187-188., though I cannot find this article in anything but Japanese - the title, however, suggests that these may be haploid polyembryos, which also occur with the almonds - these are indeed from division of the same embryo, but because they are haploid they would not actually be genetically identical, since each is taking half of the diploid chromosomes.
With only these limited descriptions to go by, which seem to be mostly observational rather than backed by any systematic study, I would hesitantly conclude that most likely what you are seeing is a fruit in which two separate ovules developed together, and therefore could be as genetically different as any two different peaches from the same tree. True polyembryos seem to be possible in stone fruits, but as a mostly rare occurrence that is only common in particular strains - when it does occur, it may be via haploidy, which means the seeds will still be genetically distinct.
The following is multiple choice question (with options) to answer.
Bananas spread their chromosomes because of | [
"bats",
"apples and oranges",
"snakes",
"Jamaican singers"
] | A | seed dispersal has a positive impact on a plant |
OpenBookQA | OpenBookQA-1662 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
Dairy has things in it that would make humans sick, so in order for dairy to be edible, this process has to take place | [
"mixing",
"boiling",
"freezing",
"pasteurized"
] | D | pasteurization reduces the amount of bacteria in milk |
OpenBookQA | OpenBookQA-1663 | eeg, terminology
Now, the brain is a lump of neurons. Different types of neurons that are there for different types of tasks. Some of them respond to electrical activity (from the nervous system) by propagating or inhibiting electrical activity. We can see this in the lab, by observing how does one single neuron behaves but to date it has been impossible to observe what EACH neuron is doing in-vivo in a functioning brain. This is the "promise" of Neuroimaging.
So, when it comes to electroencephalography, an electrical activity (of the brain) is sensed by an instrument (the EEG aparratus). Actually, in this case, a ridiculously small number of electrodes (a few tenths) is used to sense the combined functioning of a ridiculously large number of neurons (a few billions).
Because of this "imbalance" we see patterns in the electroencephalography measurements that, macroscopically, correspond to brain function. We don't really know what is happening at the neuron level, but we can observe waves of electrical activity spreading throughout the surface of the brain and we hypothesize that this is probably because of the brain's properties of segregation and specialisation (and this, go through the introduction, at least once).
In other words, certain parts of the brain are devoted to certain functions and they "connect" together to exchange information as the brain functions.
Because of this, certain "states" of cognition can be cross referenced with certain electrical patterns.
For example:
The following is multiple choice question (with options) to answer.
the nervous system sends observations in the form of electrical signals to what? | [
"cell towers",
"persons flesh",
"computers",
"plugs"
] | B | the nervous system sends observations in the form of electrical signals to the rest of the body |
OpenBookQA | OpenBookQA-1664 | species-identification
Title: What is this (water-loving) bug? For some time we've been finding these little fellows in our apartment:
They seem harmless enough, but finding them is a bit... annoying. I found the fellow above in the bathtub, and it's not uncommon to find more than one.
Unfortunately, some started to appear near the kitchen sink as well. Or outside of the bathroom on the floor (at least that's where we noticed them).
I think this thing prefers darkness over light, and seems to be drawn towards wet places or just water. These critters are also surprisingly fast.
What is it? Should we be concerned about a pest problem, or is this just a minor, unwelcome guest?
PS. We live in Poland. It is a Lepisma saccharina or silverfish.
It is rather common and yes, it's harmless.
The following is multiple choice question (with options) to answer.
Living things are in grave danger from | [
"captain crunch",
"rainbows",
"raging infernos",
"pink teddy bears"
] | C | fire causes harm to living things |
OpenBookQA | OpenBookQA-1665 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
Dead organisms, like trees provide | [
"thriving communities",
"families",
"love",
"heat"
] | A | dead organisms rot |
OpenBookQA | OpenBookQA-1666 | thermodynamics, photoelectric-effect, thermal-conductivity, absorption, solar-cells
Title: Possibility of combining photovoltaics and solar thermal energy In a private setting, photovoltaics and solar thermal energy are often harvested on the home's roof and roof area is limited. So, I thought about combining both, i.e. mounting solar collectors underneath solar cells. The rationale behind this is that the solar cells appear almost black and probably heat up considerably under irradiation. So if the collectors are in tight thermal contact to the cells, the water in the collectors might carry away the heat as usable energy, and possibly even increase the lifetime or efficiency of the cells due to the cooling effect (but this is rather engineering and not part of the question). So roof area is exploited twice (in two different wavelength windows). Moreover, if electric energy from the cells exceeds actual consumption and the battery's storage capacity, it might also be used for heating (albeit at a lower total efficiency, of course).
Can the amount of (infrared) radiation that gets absorbed (or possibly transmitted) by solar cells, and which is available as heat at the back side of the cells, be quantified by a rough calculation and either prove or disprove the benefit of such a concept? Does the almost black appearance of the solar cells fool one into thinking that they also absorb in the infrared, although they don't? Temperature of PV panels increases significantly during the day and their conversion efficiency decreases with increasing temperature. I had access to measurements of a PV plant and it showed that the total power production was about the same in August (middle of summer) and October (early fall). Although the days were shorter and there was less solar irradiance in October vs August, the air temperature was significantly lower making PV panels more efficient. For the outside temperature of 35 C, the PV panels can easily reach 70 C!
The following is multiple choice question (with options) to answer.
Solar energy is adsorbed by | [
"planted flowers under the moonlight",
"potted flowers in a windowless room",
"planted flowers on a bright, clear day",
"seeds that have just been planted in the ground"
] | C | if something is in the sunlight then that something will absorb solar energy |
OpenBookQA | OpenBookQA-1667 | thermodynamics, heat-engine
You have your flame power the $`` {\small{\begin{array}{c} \textbf{Hot Water} \\[-25px] \textbf{/ Steam} \end{array}}} "$ stream. This step is how we input the excessive driving force that comes from the flame's unnecessarily high temperature.
You hook up some random waste heat source to the $`` {\small{\begin{array}{c} \textbf{Chilled} \\[-25px] \textbf{Water} \end{array}}} "$ stream. When the contents of this stream go through the $`` \textbf{Evaporator} " ,$ they'll give off their heat to evaporate the heat pump's internal working fluid – and, since the that internal working fluid is stealing the stream's thermal energy, that stream is cooled in the process. This step is where we get the extra thermal energy from.
You hook up whatever you want to heat, like the air to your home or the food you want to cook, to the $`` {\small{\begin{array}{c} \textbf{Cooling} \\[-25px] \textbf{Tower} \end{array}}} "$ stream. As the contents of that stream flow through the absorber, the internal working fluid is reconstituted in an exothermic reaction, warming the contents of the stream. The warmed stream then exits the heat pump, only to reenter it in the condenser. In the condenser, the gaseous internal working fluid condenses on the stream, again dumping heat into it (as condensation is also exothermic).
If you do a thermal-energy balance on the system, you'll see the the thermal energy from the flame and the waste-heat source both ended up warming your home/food/whatever. In effect, you got more thermal energy out of the flame than the flame actually had by using its excess driving force to also harvest thermal energy from a waste heat source.
possibility of a “reverse-refrigerator” that cooks?
The following is multiple choice question (with options) to answer.
A source of heat is used to make | [
"ice cream",
"salad",
"lemonade",
"pastries"
] | D | an oven is a source of heat |
OpenBookQA | OpenBookQA-1668 | newtonian-gravity, free-fall
Note - Although Aristotle was partially correct, he was far from the real understanding of Gravity. Galilean Gravity was closer to the truth. Aristotle deduced that heavy objects fall faster because his observation was affected by air resistance, which is not the real cause of heavier objects falling faster. Galileo had already refuted his explanation of gravity, explaining the affect of air resistance on falling bodies. Galilean Gravity was correcter.
Please refer to this answer for a detailed explanation.
The following is multiple choice question (with options) to answer.
Galileo Galilei made improvements to the telescope to make better observations of what? | [
"plants",
"people",
"space games",
"space rocks"
] | D | Galileo Galilei made improvements to the telescope to make better observations of celestial bodies |
OpenBookQA | OpenBookQA-1669 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
Shrews are hunted by | [
"horses",
"butterflies",
"deer",
"raptors"
] | D | some birds are predators |
OpenBookQA | OpenBookQA-1670 | classical-mechanics, explosions
Title: What's driving the bucket up? Just saw this cool video from Plymouth University, which I actually found through Matthen's blog.
They fill a plastic bottle with liquid nitrogen, screw the cap on, drop it in a bucket full of warm water, cover it with ping pong balls, and when the heated, expanding gas bursts the bottle, the balls go jumping all over the place...
If you scroll the video to 3:50, you can see that the bucket jumps in the air, seemingly at the same time as the ping pong balls. Of course the force of the explosion is not pushing it up, but down. So what exactly is making it rise over 1 m off the ground?
I can only think of two possible explanations:
Elastic recoil from the material of the bucket. This seems pretty unlikely to me, as in my experience plastic buckets don't bounce much.
Pressure difference: the explosion drives everything out of the bucket, leaving a partial vacuum behind, so the atmospheric pressure outside the bucket pushes it up before air rushes back in to equalize the pressure. This seems more likely, but I would had thought that there would have been a longer delay.
Am I leaving any other possible explanation? Anybody willing to tackle a back of the envelope calculation of the height or delay for either of these? I'm willing to bet that it's simply the force of the explosion pushing on the bottom of the bucket, which pushes against the floor and makes the bucket bounce up into the air.
I doubt that it has to do with a vacuum forming inside the bucket. You're correct in thinking that we should expect more of a "delay" for the bucket to jump in this case.
And in any case, I don't believe that the explosion actually creates a vacuum in the bucket. It's simply the liquid nitrogen expanding into a gaseous state. The pressure in the bucket should never drop below 1 atmosphere. (it's not the same as an exothermic explosion, which does create negative pressure)
The following is multiple choice question (with options) to answer.
Joe used a flame torch against the side of a bucket and the entire barrel heated up, but didn't burn. What material could the bucket have been made of? | [
"walnut",
"aluminum",
"ice",
"ceramic"
] | B | metal is a thermal conductor |
OpenBookQA | OpenBookQA-1671 | predators (y2) die of natural causes (Reaction 3). At the same time , a trio of coming-of-age Predators have arrived to collect the skulls of the aliens as trophies , and the humans are caught between a deadly battle between the Spectacular and decent Aliens/Predators movie set in Antarctica where a motley group takes on extraterrestrial monsters. In The Lotka Volterra Predator-prey Model, The Changes In The Predator Population Y And The Prey Population X Are Described By The Following Equations: Δxt=xt+1−xt=axt−bxtyt Δyt=yt+1−yt=cxtyt−dyt Write A Function Simulatepredatorprey (x,y, A,b,c,d, T) That Takes In The Initial Population This problem has been solved!. The main objective was to investigate the spatio-temporal pattern of diffusive prey-predator model and the emergence of irregular chaotic pattern as a result of prey-predator interaction. Eigenvalues and eigenvectors. This project results in a Lotka-Volterra model which simulates the dynamics of the predator-prey relationship. In this study, the approximate solutions of the predator–prey system with delay have been obtained by using the modified Chebyshev collocation method. To understand how predators optimize foraging strategies, extensive knowledge of predator behavior and prey distribution is needed. The number of predators is represented by y, the number of prey by x. Yang, Yong S. (This Malthus-type equation gives. a discrete time predator prey model specified by Neubert et al[9] which utilises the Ricker model to simulate prey growth. Open the first file for this module by typing on the Matlab command line: ppmodel1. 1 Introduction. If algae and plankton communities are threatened, the entire food web may change. In this work, we investigate numerically a system of partial differential equations that describes the interactions between populations of predators and preys. This paper investigates a dynamical predator-prey interaction model that incorporates: (a) hunting cooperation among predators; (b) Allee effect in prey. At the other extreme,. b) The rabbits eat grass and breed. function to be a Di erence sequence and study the convergence of the model. (5 stars rating will be given =). In the notes, the author
The following is multiple choice question (with options) to answer.
If a new predator begins eating prey, what will happen to the preys population? | [
"heightening",
"lessening",
"abundance",
"growth"
] | B | if a new predator begins eating prey then the population of that prey will decrease |
OpenBookQA | OpenBookQA-1672 | electrochemistry, experimental-chemistry, electrolysis
That looks like rust, Ferric Oxide, exactly!
However, the cell should be Titanium, it contains no iron, but that doesn't mean it can't oxidize. Or "Rust", all metals do, Ti's oxidation would be white and powdery.
So either there is a non Ti component inside that cell that contains iron, such as steel that is breaking down, or there's something upstream of it, a Ferrous metal that's rusting, thus producing Ferric Oxide and dribbling down the pipe and into the cell. Is there any on the upstream side of the cell?
If not, then it has to be localized to inside the cell.
Another though is that you have a very high iron content in your water, mixed with the electrolysis process is causing it to oxidize on the anode, where it combines /w oxygen molecules in the water to form rust, Fe2O3.
This would keep it localized to the cell, and not be upstream, only at the cell, since that's the catalyst, or source and slightly downstream as the flow of generated Ferric Oxide tapers off.
This shouldn't effect the Ti plates though, just simply clean them with MA and you're golden!!
Ti is virtually indestructible, so they should be fine.
EDIT: Hayward says to submerge it just to the top of the cell, so the wiring harness, the electronics on the cell are not touching the acid, coiling the harness may be helpful prior to immersing. 4:1 dilute, 1 gallon of water to 1 quart of MA. And remember, always, always add the acid to the water, never, ever the other way around.
The manuf. says to soak for a few, then rinse with a high pressure hose, then repeat if needed, until the plates are clean.
BTW, Acid attacks Oxides, including Ferric Oxide.
Full thread here
Related Stackposts:
Salt product in water electrolysis
The following is multiple choice question (with options) to answer.
A common household item that may be a ferrous metal is | [
"pans",
"make up",
"books",
"towels"
] | A | an electromagnet contains cylindrical ferrous metal |
OpenBookQA | OpenBookQA-1673 | metallurgy, casting, ceramics
Title: What is the highest-temp castable refractory cement available? I very much ruined 3 $10 diamond hole saws making this ceramic insulator out of a firebrick and Ryobi drill press. Drilling out the large core took 1-2 hours and a lot of arm strength.
Therefore, I will turn to custom ceramic shops or my own castable refractory molds. I am concerned that the custom ceramic shops will be too expensive though.
So what is a refractory cement available to me that can withstand the melting point of titanium? I.e. there is a Tungsten hotnozzle about 6mm x 10mm that goes at the bottom of this ceramic tube. It's for a 3D printer that prints metal (hopefully!). So, I don't need the entire piece to withstand that temp, but just at the end point and radiating around that.
However, when I search for castable refractory cement, it seems like only one product type comes up. There are a number of approaches to this, depending on exactly what you want to achieve.
There are dense castable refractories which will operate up to 1800C. For small quantities the best source is likely to be a ceramic kiln supplier. Industrial foundry supplier may have a wider range of products but tend to deal in larger quantities.
Another possible alternative is graphite, this needs to be shielded from oxygen to prevent oxidation, but then again so does molten titanium so you would need to do that anyway as titanium is very prone to porosity and embrittlement due to absorbing atmospheric gasses, even at temperatures well below its melting point.
Zirconia based refractories can also work well at very high temperatures. One option is to use a sofer insulating refractory, or indeed rigidised ceramic wool which is coated with a layer of zirconium slurry, this is the principal behind ceramic shell investment casting.
It is also possible that any shielding gas used will also provide a significant cooling effect and as such you may find that the case temperature is significantly less than the molten metal temperature, especially as pressurised argon will give you a significant cooling effect for free.
The following is multiple choice question (with options) to answer.
Kiln fired clay ingots can insulate from | [
"ionic discharge",
"falling meteors",
"snowmen",
"underground rivers"
] | A | brick is an electrical insulator |
OpenBookQA | OpenBookQA-1674 | cell-biology, microbiology
Title: Are there any organisms that are made of more than one (~5-12) cell? Prokaryotes and eukaryotes are unicellular, made of one cell. Great. Eukaryotes are unicellular or multicellular. But the typical examples of multicellular eukaryotes we have are made of, often, trillions of cells, like us humans. Ants must still be made of many millions of cells. Are there known eukaryotes with very few cells that make them up? Like, 5, or something? Or maybe a dozen cells making up the whole organism in its fully developed state? There's Trichoplax adhaerens, a Placozoa, made of a few thousand cells. Then there is Dicyema japonicum, a simple mesozoan, made up of 9 to 41 cells. Arguably, the simplest multicellular organism is the algae Tetrabaena socialis, whose body consists of 4 cells. Then, there's the parasitic Myxozoa which have 7 cells.
The following is multiple choice question (with options) to answer.
What are made of nerve cells? | [
"bones",
"sensory system",
"nervous breakdowns",
"food"
] | B | nerves are made of nerve cells |
OpenBookQA | OpenBookQA-1675 | astronomy, sun, moon, eclipse
Title: Why don't we see solar and lunar eclipses often? Since we see the new moon at least once in a month when the Moon gets in between of the Sun and the Moon at the night and as far as I know if this happens during the day, you'll get to see a solar eclipse. Why don't we get to see this often or in the day?
Does it mean that in some part of world there's a solar eclipse when we are seeing a new moon? I'm looking for a diagram or interactive way to understand this if possible as I'm not a native English speaker, but I'll try my best to do so. If the Moon's orbit around the Earth were in exactly the same plane as the Earth's orbit around the Sun, we'd have a total solar eclipse every month (but 100% totality would be seen only from the tropics).
But in fact they're not in the same plane. The Earth's spin axis is tilted by about 23 degrees relative to the Earth's orbit around the Sun, and the Moon's orbit is closely aligned with the Earth's spin. As a result, the Sun and the Moon do not follow the same path in the sky.
We get a solar eclipse only when (a) there's a new Moon, so the Sun and Moon are in the same position east-to-west, and (b) the new Moon happens when the Sun and Moon happen to be closely aligned north-to-south.
Since the Sun and Moon are both about half a degree wide (as we see them in the sky), the 23-degree offset of their paths makes solar eclipses relatively rare events.
Lunar eclipses, which occur during the full Moon when Moon passes into the Earth's shadow, are more common because the Earth is bigger than the Moon, and so has a much wider shadow.
The following is multiple choice question (with options) to answer.
The moon sees eclipses what from Earth? | [
"the sun",
"opposite",
"through magic",
"the same"
] | B | the moon orbits the Earth |
OpenBookQA | OpenBookQA-1676 | The heights 60 through 61.5 inches are in the interval 59.95–61.95. The heights that are 63.5 are in the interval 61.95–63.95. The heights that are 64 through 64.5 are in the interval 63.95–65.95. The heights 66 through 67.5 are in the interval 65.95–67.95. The heights 68 through 69.5 are in the interval 67.95–69.95. The heights 70 through 71 are in the interval 69.95–71.95. The heights 72 through 73.5 are in the interval 71.95–73.95. The height 74 is in the interval 73.95–75.95.
The following histogram displays the heights on the x -axis and relative frequency on the y -axis.
## Try it
The following data are the shoe sizes of 50 male students. The sizes are continuous data since shoe size is measured. Construct a histogram and calculate the width of each bar or class interval. Suppose you choose six bars.
9; 9; 9.5; 9.5; 10; 10; 10; 10; 10; 10; 10.5; 10.5; 10.5; 10.5; 10.5; 10.5; 10.5; 10.5
11; 11; 11; 11; 11; 11; 11; 11; 11; 11; 11; 11; 11; 11.5; 11.5; 11.5; 11.5; 11.5; 11.5; 11.5
12; 12; 12; 12; 12; 12; 12; 12.5; 12.5; 12.5; 12.5; 14
Smallest value: 9
Largest value: 14
Convenient starting value: 9 – 0.05 = 8.95
Convenient ending value: 14 + 0.05 = 14.05
$\frac{14.05-8.95}{6}=0.85$
The calculations suggests using 0.85 as the width of each bar or class interval. You can also use an interval with a width equal to one.
The following is multiple choice question (with options) to answer.
A mother is six feet tall and the father is almost seven feet tall. When their son reaches maturation, he will likely | [
"measure similarly",
"be very short",
"be invisible",
"be under weight"
] | A | height is an inherited characteristic |
OpenBookQA | OpenBookQA-1677 | newtonian-mechanics, inertia
Title: How would I move if I grew by a factor of 3 in each physical dimension? Suppose, for the sake of this thought experiment, I am structurally identical to an average human, with the only difference being that my body is scaled in all directions by factor of 3. This would result in me having 27x more mass than a normal human.
In cinema, giants tend to move very sluggishly, and that seems to match our expectation of creatures of that size--after all, most people think of whales and elephants as being very large, slow-moving creatures.
However, I now also have 27x more muscle mass... Wouldn't my much larger muscles provide the necessary force to counteract the increase in inertia?
Barring a slight increase in air resistance, wouldn't my body movements (walking, running, moving my arms) be indistinguishable from that of a normal-sized human, and not sluggish as depicted in movies? Assuming for a moment that your bones are proportionately stronger... (because you are asking about motion, not strength: but see for example this question about scaling in nature) That still leaves us with some physics that "doesn't scale well".
First, there is the issue of muscle mass: assuming your muscles are made of the same fibers, their strength (ability to exert a force) goes as the cross sectional area, while their power (force times velocity) scales with the total volume (if each element of muscle contracts by some amount, the total contraction of the muscle, and thus the velocity, depends on the length; and since the force depends on the cross section, the power scales with the volume; this also makes sense from an energy balance perspective, assuming that each cell expends a certain amount of energy per unit time, the total power will scale with the number of cells). So you are not actually "27 times stronger" when you are scaled up - your ability to accelerate yourself is less than if you were your normal size.
The following is multiple choice question (with options) to answer.
Humans have the ability to change how much they weigh, but we cannot change how tall we are because that is | [
"expensive",
"impossible",
"hereditary",
"Too hard"
] | C | height is an inherited characteristic |
OpenBookQA | OpenBookQA-1678 | planet, natural-satellites
Asteroids are sometimes found orbiting one another and I rarely hear that defined as a central asteroid with a smaller asteroid orbiting it, it's more often called a binary asteroid. I've never heard it called a baby asteroid orbiting it's parent, but again, definitions fall into a grey area if one asteroid is quite a bit larger than the other.
This XKCD comic addressed circumbinary orbits and "the other kind", which doesn't have a name. Not everything needs a name, and in this case, I don't there is an official one. "Central body" "Central object" or "Parent" work just fine as familiar and common terms.
The following is multiple choice question (with options) to answer.
Our only satellite is found with the other | [
"nine planets",
"nebula",
"red giant stars",
"Andromeda galaxy"
] | A | the solar system contains the moon |
OpenBookQA | OpenBookQA-1679 | concentration, food-chemistry, drugs
Lithium and potassium are among few cations with a salty flavor similar to that of sodium, albeit weaker. Citrate reduces the saltiness further. According to Ref 2, the saltiness of lithium and potassium can be estimated to be ~0.4 and 0.6 that of sodium, repectively, while Ref 3 explains that citrate has an inhibitory effect.
Consider now the potassium concentration (~170 mg/L) in the current formula of 7-up. Potassium is added as the citrate salt, and could be replaced with the lithium salt with little change in taste perception, according to what is reported on the relative saltiness of the cations and citrate salts. This suggests that if the taste of the beverage has remained reasonably constant since inception, it is not unreasonable to estimate an upper bound of ~200 mg/L in the concentration of lithium citrate (replacing the potassium salt) in the orginal recipe.
Note this is based entirely on the taste perception and not on any medical implications of consuming lithium at such concentrations. Lithia water (a brand of spring water sold in the USA) contains only ~0.5 mg/L of lithium. For reference, an online medical advice site suggests that a dose for treatment of depression is ~60 mg of lithium daily. So a dose of ~60 mg lithium citrate per serving certainly seems high relative to lithium-rich spring water but is just about a typical clinical dose.
References
Rodengen, Jeffrey. The Legend of Dr. Pepper/7Up. Fort Lauderdale: Write Stuff Syndicate, 1995. ISBN 0-945903-49-9.
McLaughlin, S., Margolskee, R.F.. The Sense of Taste. American Scientist, 82, 538-545 (1994).
C.M.D. Man. Technological functions of salt in food products. in Reducing Salt in Foods, Woodhead Publishing, 2007. ISBN 978-1-84569-018-2.
Gielen, Marcel; Edward R. T. Tiekink (2005). Metallotherapeutic drugs and metal-based diagnostic agents: The use of metals in medicine. John Wiley and Sons. p. 3. ISBN 0-470-86403-6.
The following is multiple choice question (with options) to answer.
Cows know there is salt in a mineral lick because | [
"they have receptors on their tongue that allow them to experience spice and seasonings",
"a cow in the ocean told them it was there",
"it's on their side of the pasture's fence",
"they evolved where there were great redwood trees"
] | A | animals taste flavors |
OpenBookQA | OpenBookQA-1680 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Dogs are known to chew their food once or twice, but like all organisms they can | [
"sense the flavor",
"hate it",
"choke",
"sell it"
] | A | animals taste flavors |
OpenBookQA | OpenBookQA-1681 | water, pressure, building-physics
Title: Water flushed down, water pumped up (in buildings) I live in a tall building (20 floors) on a mountain. Because the water pressure from the water company is not enough, there is a water pump at the last floor which is activated each time someone is using fresh water in his apartment.
To me, that's a big waste of energy, and I think that in theory it would be possible to reuse the used water which is going down to pump some fresh water up.
I wonder if such device already exist on the market, and I would like to know how such device would be called. Would there be a problem to operate with such a height difference? In theory, yes, this could be done. Pretty much exactly as much gravitational energy is lost by the water coming down as is gained by the water going up, so you could then supply the water while hardly using any energy at all. (Just enough to offset the heat generated by friction in the pipes.)
One way in which it can be done in theory is simply to connect two gear pumps with a solid axel. Water from the down pipe will force the axel to turn, which then drives the up pump. Water can be made to flow by applying just a little bit of extra torque to the axel.
However, in practice I don't think this would be done. I imagine there would be a lot of practical issues involved in passing waste water through a pump - it would at least have to be filtered first - and as EnergyNumbers points out in a comment, the energy needed to pump water up 20 floors is pretty small in comparision to (for example) heating the apartments.
The following is multiple choice question (with options) to answer.
A person may use water from a treatment plant so that it is | [
"free from wetness",
"free of chunks",
"free from governments",
"free from ice"
] | B | treating water is used to remove harmful substances before drinking |
OpenBookQA | OpenBookQA-1682 | quantum-spin, atoms
The bonds between the atoms are obviously split when the paper is torn, but is there a way to put them back together?
the answer is yes, because this is precisely why paper recycling works. The incoming used paper is washed, to remove ink and other contaminants, and then left to soak in a particular solution (the composition of which partly determines the color, consistency, strength, etc. of the resulting paper), where it eventually turns into a slurry. Paper is made of long fibers of cellulose arranged essentially randomly; when immersed in water, those fibers spread out throughout the solution. Then the slurry is rolled into sheets and left to dry; as the water leaves, the cellulose fibers end up weakly attracted to each other (the "weak" part is important; it's why you can easily tear a piece of paper in the first place), which leads to a similar kind of random arrangement of weakly-bonded cellulose fibers that we start with.
The following is multiple choice question (with options) to answer.
A river is moving along a path and a piece of paper falls in it. The paper | [
"screams",
"flies",
"sinks",
"relocates"
] | D | flowing liquid can push objects |
OpenBookQA | OpenBookQA-1683 | phase
The vapor pressure must reach the saturation vapor pressure for dew or frost to form. This happens at the dew point or frost point temperature, which is dependent on atmospheric pressure and the absolute amount of vapor in the air. As atmospheric temperature increases, the dew/frost point temperature increases. As atmospheric pressure increases, the vapor pressure increases. At very low temperatures, the dew/frost point temperature is very low.
http://wattsupwiththat.com/2009/06/13/results-lab-experiment-regarding-co2-snow-in-antarctica-at-113%C2%B0f-80-5%C2%B0c-not-possible/
https://stevengoddard.wordpress.com/2014/06/03/antarctica-gets-cold-enough-to-freeze-co2/
The following is multiple choice question (with options) to answer.
Once the grounds frost over and the air grows chilled | [
"beaches are opened",
"humans go naked",
"birds lay eggs",
"roses die"
] | D | usually plants die or become dormant during the winter |
OpenBookQA | OpenBookQA-1684 | zoology, microbiology, pathology
Title: Prevention of disease spreading in animal kingdom It's my first question on here, so I'm not sure If my question fits the theme. Please refer me to the appropriate one, If I have made a mistake.
So a question that I wanted to ask has to do with whether or not animals potentially try to avoid spreading diseases. So I was thinking... In an event that a really deadly disease emerges in a population, it would be really dangerous for animals that live in social groups, of any size really, not to have any instinctual behaviours that try and prevent the disease to spread. Animals that live in big heads, like wildebeests would just probably leave the diseased individuals behind, apes and monkey could potentially cast out individuals from the group, etc. Ants have separate sections in their tunnels that serve as graveyards, I presume for this exact purpose.
A lot of parasitic organisms have adaptations that specifically target animals with social behaviour, so why wouldn't animals adapt against that?
Something that also came to my mind is that this could possibly evolve not as a social behaviour of a group, but sometimes that individuals in a group would do, for example self isolation. However, I do not find this likely, I possibly requires higher cognitive understanding of disease spread.
Am I way of base here? If not, could you please provide some interesting examples you are familiar with.
The following is multiple choice question (with options) to answer.
Most animals have some type of defense mechanism to protect them from predators. The Octopus has | [
"its ink",
"flying",
"yelling",
"crying"
] | A | ink is used for hiding from predators by octopuses |
OpenBookQA | OpenBookQA-1685 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
A species' habitat is those places where it can find food, shelter, protection and | [
"predators to escape",
"rivers to cross",
"mountains to climb",
"mates for reproduction"
] | D | habitat destruction causes animals to move to find shelter in another habitat |
OpenBookQA | OpenBookQA-1686 | star, galaxy
If you're on a farm, away from cities, in a place with reasonably low light pollution, and your eyes are good, and you've been sitting in perfect pitch black darkness for at least 30 minutes prior - when you look up you can reasonably expect to see a few thousand objects, mostly stars. Keep looking, and after a while you will distinguish one or two thousand more stars, very faint, that you could not see at first sight. Practice this steadily for a few years, and you'll add maybe another thousand; but you won't be able to see those all at once - only one at a time.
Now travel to the Cerro Tololo site in Chile, up in the mountaineous desert, zero light pollution, excellent transparency, and you'll multiply all those numbers by a factor of 2x ... 5x.
As you can see, the numbers are very flexible because there are so many factors involved. You can't just slap a 44k label on it and call it a day; that doesn't make any sense in reality. Astronomers know that the pure magnitude number doesn't mean much by itself, because it is just one factor among many.
In a place with very high light pollution (like where I live, in the middle of a large, dense, sprawling urban area in California), you'd be lucky if you can see a hundred stars at night.
Or, in a place with zero light pollution, shine a flashlight into someone's face, and you've temporarily blinded them. You've reduced the number of stars they could see by an order of magnitude for the next half hour (night vision gradually recovers, and it takes 30 minutes to fully recover, according to US military manuals and visual astronomers practice).
The following is multiple choice question (with options) to answer.
A person thinks they see a UFO. They look closely, but the object becomes hard to see in the night sky as | [
"gets closer to the person",
"buys a new house",
"builds a large park",
"it puts distance between them"
] | D | as distance from a source of light increases , that source of light will appear dimmer |
OpenBookQA | OpenBookQA-1687 | ocean, glaciology, ice, ecology, cryosphere
Title: Do icebergs have any impact on ecology? Are icebergs neutral actors in the environment, or do they have any impact on the local ecology. Do they have any environmental impacts that might influence any part of the biosphere? Yes, they have many impacts:
They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (here is one).
They transport sediments and nutrients into the ocean.
They provide safe rest areas for animals like seals, birds and penguins.
They impact the temperature of surface waters, specially in fjords.
They stir the sea floor in shallow waters
And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.
The following is multiple choice question (with options) to answer.
Glaciers doing what has a negative impact on the glacial environment? | [
"liquifying",
"growing",
"freezing",
"cooling"
] | A | glaciers melting has a negative impact on the glaicial environment |
OpenBookQA | OpenBookQA-1688 | thermodynamics, evaporation, gas, liquid-state
On the water surface, knowing the temperature, we can estimate the vapor pressure and vapor mixture fraction. Then there will be an diffusion process for the water vapor to move out and for the ambient air to move in. Because the water surface doesn't allow the air to further move, a circulation forms. When the water vapor moves out, the water vapor pressure drops, so more liquid water evaporates to fill up the loss of water vapor. The evaporation associates latent heat so water surface area temperature drops (you may see dew on the bowl wall). Then a heat transfer process starts which may initiate water circulation as well.
As this is complex, doing test might be a quick way to get the K value if you assume it is a constant, which is questionable.
The following is multiple choice question (with options) to answer.
Water vapor helps with? | [
"The sidewalk",
"A pool",
"A cat",
"A habitat"
] | D | water vapor is found in the atmosphere |
OpenBookQA | OpenBookQA-1689 | zoology
Title: Are penguins plantigrade or digigrade? I'm trying to rig a 3D model of a penguin, but I don't know where to put the bones near the ankle because I can't tell if they're digigrade or plantigrade. Nearly all birds are digigrade, but penguins spend a lot of time walking and don't generally grasp or run with their talons. Plantigrade.
The penguins are highly specialized for their flightless aquatic
existence. The feet are located much farther back than those of other
birds, with the result that the bird carries itself mostly upright;
its walk can thus be described as plantigrade (i.e., on the soles).
The sole comprises the whole foot instead of just the toes, as in
other birds. The most notable characteristic of the group is the
transformation of the forelimb into a paddle. This is accompanied by a
body morphology particularly adapted to movement in a liquid medium.
The thoracic (rib) cage is well developed, and the sternum bears a
pronounced keel for the attachment of the pectoral muscles, which move
the flippers. The flipper has the same skeletal base as the wing of
flying birds but with its elements shortened and flattened, producing
a relatively rigid limb covered with very short feathers—an ideal
organ for rapid propulsion. The body plumage likewise consists of very
short feathers, which minimize friction and turbulence. The density of
the plumage and the layer of air that it retains provide almost
complete insulation of the body.
https://www.britannica.com/animal/penguin#ref3467
The following is multiple choice question (with options) to answer.
One breed of penguins, the Galapagos Penguin lives in the warm waters off the coast of | [
"Equador",
"India",
"Haiti",
"Australia"
] | A | warm-weather organisms live in warm climates |
OpenBookQA | OpenBookQA-1690 | thermodynamics, heat-engine
You have your flame power the $`` {\small{\begin{array}{c} \textbf{Hot Water} \\[-25px] \textbf{/ Steam} \end{array}}} "$ stream. This step is how we input the excessive driving force that comes from the flame's unnecessarily high temperature.
You hook up some random waste heat source to the $`` {\small{\begin{array}{c} \textbf{Chilled} \\[-25px] \textbf{Water} \end{array}}} "$ stream. When the contents of this stream go through the $`` \textbf{Evaporator} " ,$ they'll give off their heat to evaporate the heat pump's internal working fluid – and, since the that internal working fluid is stealing the stream's thermal energy, that stream is cooled in the process. This step is where we get the extra thermal energy from.
You hook up whatever you want to heat, like the air to your home or the food you want to cook, to the $`` {\small{\begin{array}{c} \textbf{Cooling} \\[-25px] \textbf{Tower} \end{array}}} "$ stream. As the contents of that stream flow through the absorber, the internal working fluid is reconstituted in an exothermic reaction, warming the contents of the stream. The warmed stream then exits the heat pump, only to reenter it in the condenser. In the condenser, the gaseous internal working fluid condenses on the stream, again dumping heat into it (as condensation is also exothermic).
If you do a thermal-energy balance on the system, you'll see the the thermal energy from the flame and the waste-heat source both ended up warming your home/food/whatever. In effect, you got more thermal energy out of the flame than the flame actually had by using its excess driving force to also harvest thermal energy from a waste heat source.
possibility of a “reverse-refrigerator” that cooks?
The following is multiple choice question (with options) to answer.
A source of heat may come from | [
"a cold shower",
"holding hands",
"holding ice",
"Antartica"
] | B | a stove generates heat for cooking usually |
OpenBookQA | OpenBookQA-1691 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
What usually happens to animals when humans need new to grow more corn? | [
"animals become magical",
"animals forced out",
"animals gain habitat",
"animals are happy"
] | B | humans moving into an environment usually causes native species to lose their habitats |
OpenBookQA | OpenBookQA-1692 | photosynthesis, chloroplasts
Title: Chloroplasts in an animal cell What would happen if we inject a chloroplast organelle into an animal cell?
Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could there be photosynthesis in such a cell, or will some of the necessary mechanisms be missing? To answer your bigger question:
Yes, most of this is possible - under some conditions -, and animals and animal cells can acquire chloroplasts, and use them.
E.g.: see Elysia chlorotica whose cells actively take up chloroplasts and use them, and keep them alive (though not replicating). - Though some genes of algae are also contained in the Elysia chlorotica genome - which may be considered as partial replication.
Also there are salamanders that have replicating algae within them (since embryogenesis) - even algae (with chloroplasts) within animal cells - though here the algae might be rather understood as symbionts or "cell types", and the animal cells don't have the chloroplasts by themselves.
The following is multiple choice question (with options) to answer.
chloroplasts are rarely found in | [
"root hair cells",
"Eukaryotic cells",
"leaf guard cells",
"rose petal cells"
] | A | a plant cell contains chloroplasts |
OpenBookQA | OpenBookQA-1693 | How about this? There is a 30% chance you'll go to New York and a 100% chance you'll go to the Empire State Building if you go to New York (because why else would you go to New York? kidding...). Does this mean there's a 100% chance you'll go to the Empire State Building? Well, since you have to go to NY to go to the ESB, that would mean there's a 100% you'll go to New York - and now we're being contradictory! So this interpretation makes no sense and is never what we mean mathematically or in plain English.
"The DVD Is either at my parents, my porch, or my living room. What is the % chance it's on my porch?", the answer is 33%.
This is definitely wrong. I'm pretty sure you either have ebola or you don't have ebola. Up to you whether you need to call 911 and get yourself quarantined right away because there's a 50% chance you have ebola. Or perhaps the doctors gave your sick relative 6 months to live, but your relative might live a year or two years or three years or four years or five years, which means there's at least an 86% chance the doctor is wrong.
Now put 10 red m&ms in a bag and 1 blue one. Grab one without looking. Since there's two possibilities, there's a 50% chance it's a blue one, right? So I'll bet you a dollar that it's red and you bet me a dollar that it's blue, and we'll see who's paying for lunch later.
The following is multiple choice question (with options) to answer.
Which of these is the most likely to result in a trip to the hospital? | [
"a flashback explosion inside a container",
"watching a television drama about heart attacks",
"filling a bucket of water with a hose",
"eating waffles that are just the right temperature"
] | A | when a gas in an open container evaporates, that gas spreads out into the air |
OpenBookQA | OpenBookQA-1694 | optics, electromagnetic-radiation, refraction
Title: Can anyone explain to me why light is not dispersed into a spectrum through a parallel glass slide, but only through a prism? The question pretty much sums up what I need to know. Why is it that light only gets dispersed into a spectrum when travelling through two non-parallel sides(like a prism) and not through something like a glass slide with parallel slides.
And how does this experiment(an experiment conducted by Newton) explain this? Because this is what is in my school textbook. If you think of the two parallel glass sides as canceling each other out you are pretty close to it. The first impact (low to high indices) does in fact disperse frequencies if the light is coming in at an angle, but the exits (high to low) mostly cancels that effect. There actually can be some small residual effects leading to small colored fringes.
The prism works better because the oppositely angled sides enhance rather than cancel the dispersion effects.
Here are the results of some further analysis and experimentation.
Part of the answer for why color effects are so hard to find when light passes through flat glass plates appears to be in the eye of the beholder... literally!
Here's the scoop: Angled light entering a flat plate should at first fan out its angles by color while within the plate. By symmetry, however, those slightly fanned out rays of colored light return to their original paths when they reach the second surface an re-emerge. So, the new rays will show essentially no difference in direction from their paths in the original beam, but will no be spaced very slightly apart from each other in rainbow order. For a typical plate of glass this separation would seldom be more than a millimeter, and for most glasses would be a lot less than that.
Now picture a point of light on one side of the glass and a human eye on the other side. Arrange both so that the line between then is at a sharp angle to the surface of the glass. Let's look at the ray going from the point to the center of you pupil. Your eye focuses that parallel white light as a single point on the retina, as expected. But When the angled glass plate is inserted, the same ray of light gets spread out along a tiny distance, usually much less than a millimeter. However, each colored ray in this bundle remains parallel to the original path.
The following is multiple choice question (with options) to answer.
When light energy enters a prism it emits all the colors by | [
"deflecting the light",
"reflecting the light",
"consuming the light",
"refracting the light"
] | D | a rainbow is formed by refraction of light by splitting light into all different colors |
OpenBookQA | OpenBookQA-1695 | genetics, reproduction
http://medical-dictionary.thefreedictionary.com/Infertility
http://medical-dictionary.thefreedictionary.com/sterility
http://www.acog.org/~/media/For%20Patients/faq011.pdf
The following is multiple choice question (with options) to answer.
What is an example of reproduction? | [
"reading books",
"laying down",
"walking",
"unhatched chicks"
] | D | An example of reproduction is laying eggs |
OpenBookQA | OpenBookQA-1696 | botany, reproduction
Most new commercial tomatoes, including new garden tomatoes, are F1 hybrids. The seeds you plant in the field are the result of crossing two parents, as described above. (...) Garden catalogs will tell you whether the seed you are buying is hybrid. If you are getting your fruits from the store, you can count on them being hybrids unless they are marked as heirloom.
The following is multiple choice question (with options) to answer.
A person wants to make some tomato plants grow, so they get | [
"older",
"dirt",
"corn",
"married"
] | B | soil is a renewable resource for growing plants |
OpenBookQA | OpenBookQA-1697 | acoustics
Title: Resonance in a 1 ft granite box
I have a granite cube made using 6 slabs of granite 1 foot square and 1 inch thick. The top and bottom slabs have a 1 inch margin around the edge. The slabs are just set together, not notched or mortared or anything.
I also have a concrete block with pipes running through it that generates a sonic pulse/compression wave from a valve closing. If this were a regular water system we'd all call it water hammer. This water hammer comes out the top of the block. It is assumed that this block is not going to self destruct from the water hammer. It pulses about 60 times per minute. There is a working example of this block that I have seen online, so I know how to build it.
The following is multiple choice question (with options) to answer.
A granite counter top | [
"will always cost more than a mountain",
"should be cleaned with mineral water",
"is only found in a kitchen",
"is made of minerals"
] | D | rock is made of minerals |
OpenBookQA | OpenBookQA-1698 | human-biology, microbiology, food, digestive-system, mycology
Aflatoxins produce acute necrosis, cirrhosis, and carcinoma of the
liver in a number of animal species; no animal species is resistant to
the acute toxic effects of aflatoxins; hence it is logical to assume
that humans may be similarly affected. A wide variation in LD50 values
has been obtained in animal species tested with single doses of
aflatoxins. For most species, the LD50 value ranges from 0.5 to 10
mg/kg body weight. Animal species respond differently in their
susceptibility to the chronic and acute toxicity of aflatoxins. The
toxicity can be influenced by environmental factors, exposure level,
and duration of exposure, age, health, and nutritional status of diet.
Aflatoxin B1 is a very potent carcinogen in many species, including
nonhuman primates, birds, fish, and rodents. In each species, the
liver is the primary target organ of acute injury. Metabolism plays a
major role in determining the toxicity of aflatoxin B1; studies show
that this aflatoxion requires metabolic activation to exert its
carcinogenic effect, and these effects can be modified by induction or
inhibition of the mixed function oxidase system.
The following is multiple choice question (with options) to answer.
An animal is likely to be negatively impacted by food with | [
"animals",
"fungi",
"water",
"plants"
] | B | food spoiling has a negative impact on the health of the animal that eats that food |
OpenBookQA | OpenBookQA-1699 | java, optimization, programming-challenge, pathfinding
Title: Contest code for a maze problem I would like to ask your comments on my contest code for the following problem:
We're going to have a slightly more logical puzzle today. We're going to write a program that will find a path through a simple maze.
Formal Inputs & Outputs
Input Description
Through standard console,
you will be given two numbers X and Y. After that you will be given a
textual ASCII grid, X wide and Y tall, of walls # and spaces. In the
maze there will be exactly one letter S and exactly one letter E.
There will be no spaces leading to the outside of the maze - ie. it
will be fully walled in.
Output Description
You must print out the maze. Within the maze there
should be a path drawn with askerisks * leading from the letter S to
the letter E. Try to minimise the length of the path if possible -
don't just fill all of the spaces with *!
Sample Inputs & Outputs
Sample Input 15 15
###############
#S # #
### ### ### # #
# # # # #
# ##### ##### #
# # # #
# ### # ### ###
# # # # # #
# # ### # ### #
# # # # # # #
### # # # # # #
# # # # # #
# ####### # # #
# #E#
###############
The following is multiple choice question (with options) to answer.
A person lost in a maze will need to find their way out alone, but a person lost in a forest may | [
"rely on television",
"rely on magnets",
"rely on spirits",
"rely on deer"
] | B | natural magnetism is used for pointing north by a compass |
OpenBookQA | OpenBookQA-1700 | organic-chemistry, physical-chemistry, biochemistry, alcohols
Title: Storage of Urine Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle. If you take offense at this, please do not continue reading except to be helpful in the scientific goal. I know this subject won't suit many types of people, so just ignore it if that is your case.
I noticed first of all that urine is not at all as sterile as people say that it is. The rate of growth of bacteria is relatively slow, but as a precaution, I found the need to use additional measures to prevent the growth of bacteria. I settled on the following method: I have two bottles and I add to each bottle about enough salt as can be soluble in the urine and sometimes maybe a little more. The one bottle then fills up throughout the day and is emptied, washed, and refilled with salt. The salt helps to kill the bacteria which would be lingering in the empty bottle. The next day, the bottle stays empty and the other is used.
I would add that I discovered that the bacteria (without the salt) does not usually grow unless the bottle is left with urine for two days. After this, however, that same bottle (without the salt) would retain the bacteria and immediately grow, if used again.
This system works relatively well, so long as it is done every day. It will even withstand 2 days with only moderate growth. (If I should leave it by mistake for longer it can get ugly). Nevertheless, I am still looking to improve upon this. One reason is that, if I drink less water or relieve myself normally, the bottle does not fill in one day. I am looking for someone with knowledge of chemistry to help me find a substance that can be added to this solution which fits a number of common sense criteria. I will also add a list of the substances that I have tried or already considered.
Necessary qualities
The following is multiple choice question (with options) to answer.
A person wants to conserve toothpaste so they will | [
"use it generously",
"use it indiscriminately",
"throw it out",
"use it stingily"
] | D | An example of conservation is avoiding waste |
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