source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-201 | radiation
You see similar things happening here. The metal rod at the top of the lamp acts as a capacitive ground - given the very high voltage, a tiny charge will flow from the tip of the filament to the rod. There is a small amount of gas in the tube which is ionized and gives rise to the light you see. The electrons eventually bombard the metal "anode" and produce Bremsstrahlung - note that without the metal, you were getting a glow and no reading on the Geiger counter. There is a similar demonstration online which is more convincing in its use of conventional materials, but which otherwise shows many of the same phenomena.
It is almost certainly very inefficient. Most of the energy in an X-ray tube is converted to heat as the electrons burrow too deeply into the tungsten target for their radiation to escape- apart from the fact that only the most violent deceleration produces X-rays with high enough energy to penetrate the bulb and be detected.
I noticed that when the "alpha window" was removed, the reading in your video went up. Since there was also a biscuit tin and glass bulb in the way I suspect there was a lot more low energy radiation generated than was detected. Good stuff for skin cancer.
The experiment as shown should not be repeated. Not only were the HV precautions extremely poor, but so were the radiation safety precautions. Please don't try this at home...
The following is multiple choice question (with options) to answer.
a toaster converts electricity into radiant waves for | [
"browning bagels",
"roasting meats",
"toasting corn",
"burning cheese"
] | A | a toaster converts electrical energy into heat energy for toasting |
OpenBookQA | OpenBookQA-202 | optics, electromagnetic-radiation, visible-light, reflection, geometric-optics
Title: We know that a window can actually reflect light. But if the window has some dirt sticking to it, the image we see sometimes get magnified. Why? Well, I was traveling in a bus yesterday and saw this occur. The board that separates the passengers from the driver's had something written on it and I saw that the window that was a few meters away from the board reflected all of the things written.. But the window had some dirt on the part where I saw the image of the writings... And, they appeared to be enlarged just at the point where dirt was present. The open spaces between dirt particles each acts like a "pinhole camera" to magnify the image behind the dirty glass pane. The magnification is slight but noticeable. Try this experiment: make a small triangular hole shape by putting three fingertips together so as to leave a gap at their intersection. by pressing your fingertips together, you can make the size of the hole shrink; by relaxing them, you can make the hole larger.
That hole will act as a pinhole camera. now look through the hole at your computer screen from about 24 inches away and vary the hole size. you will find a certain diameter at which the image you see through the hole will get sharper and the text on the screen will become easier to read.
The following is multiple choice question (with options) to answer.
A light is refracted when | [
"it shines at a gem",
"it shines at a mirror",
"it reflects off a spoon",
"it reflects off a car"
] | A | refraction is when light bends |
OpenBookQA | OpenBookQA-203 | energy, fuel, environmental-chemistry
Title: Effect of coal and natural gas burning on particulate matter pollution I sometimes hear people talking about how we should replace coal burning plants with natural gas ones, to alleviate the case of particulate matter pollution. What exactly is the difference between coal fuel and natural gas that makes the latter seem "cleaner"?
At the same energy outcome, natural gas produces less carbon dioxide than coal. In a way, natural gas is half way between coal and hydrogen.
Coal produces smelly smoke, solid particles, sulfur dioxide and minor or trace heavy metal pollutants.
It is less known to common people, but power plants burning coal are more significant source of radioactive pollution than nuclear plants. This pollution is very diluted, but rather significant in absolute amount. Coal ash, used in past as a filler for some construction materials, has lead in some cases to significantly increased content of radium-226 in building walls. This radium is a product of long term decay of natural uranium. It further decays while producing radioactive gaseous radon-222, which is dangerous in long term inhalation because of lung cancer. As it stays in lungs as polonium-218 and its decay products.
See e.g. Uranium produced from coal ash
... the uranium concentration in the ash pile is about 150-180 parts per million, about 1/4th of the concentration often thought of as commercially viable for ISL[In Situ Leaching] mining. However, coal ash piles have some physical characteristics that might help overcome that disadvantage since they may be easier to drill and it might be easier to protect the local groundwater from contamination. ...
See Radon in building materials by Czech government agency for radiation protection.
The following is multiple choice question (with options) to answer.
coal is a resource that | [
"constructs with difficulty",
"makes everything sanitary",
"shines in light",
"cools the air"
] | A | coal is a nonrenewable resource |
OpenBookQA | OpenBookQA-204 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
After the wolf ate all the rabbits he survived on: | [
"water",
"plants.",
"fat",
"luck"
] | C | an animal can survive in an environment with little food by storing fat |
OpenBookQA | OpenBookQA-205 | species-identification, ornithology
Title: House sparrow or something else? These little flying fellows seemed to have made themselves a small nest in the crevices of the roof of my house (I live in Poland). I don't know if this makes a difference, but I do live near a small park.
I'm wondering if this is a house sparrow or something else.
On one of the photos I could swear these look like common sparrows, but on another (the one where the wings are apart) it seems like a different species. It also seemed larger than a sparrow, but is hard to tell due to the distance at which I've seen the birds and the photos were taken. One other notable feature was that they seemed very loud...
Any help? Based on your image I would rather identify it as an Eurasian Tree Sparrow. They are pretty similar to the House Sparrow, but have a distinct black spot below their eyes which is missing for the House Sparrows (image from the Wikipedia):
The following is multiple choice question (with options) to answer.
A bird makes its home in various places, such as | [
"groves of plants",
"waterways",
"city streets",
"public parks"
] | A | some birds live in forests |
OpenBookQA | OpenBookQA-206 | genetics, homework, human-genetics
However I really feel like I'm wrong about these assumptions since the math really doesn't add up. The likelihood that so many carriers for a relatively rare disorder all coming together and the fact that 3 of the 4 offspring of the grandparents died with only a 25% chance all seems improbable.
It could be that John's son doesn't have the disorder and what he has is something completely different. What do the geneticists say? This is a very rough draft about the case, not verified, and should not be used for any medical conditions. Ask your own doctor. It is just for demonstrating some Mathematics and genetic passing generally.
Condition: Muscular atrophy
Differential conditions: TODO
Support: history of genetic passing in -1 and -3 generations
Disease
Muscular atrophy as a condition jumps over a generation. The environment/living of your greatgreatgrandfathers determine your grandfathers future, as a rough estimate.
The disease's common feature is recessive autosomality.
Assumptions
Autosomal recessive disease because everyone who exhibits symptoms is not be able to reproduce due to their early death.
TODO genetic passing
What is the genetic profile? Is there any other autosomal recessive diseases in the gene map?
Proposed probabilities where the random variables $X = disease$ and $Y = carrier$ such that the subscript 0, -1, -2 and -3 is about new children's, John's, parents' and grandparents' status, respectively.
Both of John's grandparents must have been carriers
\begin{equation}
P(Y_{-3}) = 100\%
\end{equation}
The probability of John's dad and any aunts and uncles having the disorder is (TODO think this again with the correct genetic passing)
\begin{equation}
P(X_{-2}) = 25\%
\end{equation}
The probability of being a carrier is for dad, aunts and uncles (TODO think this gain with the appropriate genetic passing)
\begin{equation}
P(Y_{-1}) = 50\%
\end{equation}
Disease as a process
$X \sim P_{i}(\mu, \sigma)$, $i = -3, -1, 1, ...$ where I propose the mean $\mu$ and the variance $\sigma^2$.
The following is multiple choice question (with options) to answer.
To identify the percent chance of a trait being passed down we need at least | [
"one box",
"two boxes",
"three boxes",
"four boxes"
] | D | a Punnett square is used to identify the percent chance of a trait being passed down from a parent to its offspring |
OpenBookQA | OpenBookQA-207 | java, reinventing-the-wheel, console, unix
With clothes the new are best, with friends the old are best.
He is truly wise who gains wisdom from another's mishap.
Beware of a dark-haired man with a loud tie.
Today is the last day of your life so far.
Flee at once, all is discovered.
Man who falls in vat of molten optical glass makes spectacle of self.
Go directly to jail. Do not pass Go, do not collect $200.
For a good time, call 8367-3100.
Those who can, do; those who can't, simulate.
Those who can, do; those who can't, write. Those who can't write work for the Bell Labs Record.
God does not play dice.
This fortune is inoperative. Please try another.
Laugh, and the world ignores you. Crying doesn't help either.
No amount of genius can overcome a preoccupation with detail.
You will feel hungry again in another hour.
You now have Asian Flu.
God made the integers; all else is the work of Man.
Disk crisis, please clean up!
You auto buy now.
Many are called, few are chosen. Fewer still get to do the choosing.
Try the Moo Shu Pork. It is especially good today.
Many are cold, but few are frozen.
The early worm gets the bird.
He who hesitates is sometimes saved.
Time is nature's way of making sure that everything doesn't happen at once.
The future isn't what it used to be. (It never was.)
Can't open /usr/lib/fortunes.
If God had wanted you to go around nude, He would have given you bigger hands.
It is better to have loved and lost than just to have lost.
A journey of a thousand miles begins with a cash advance from Sam.
Disk crunch - please clean up.
Center meeting at 4pm in 2C-543
I will never lie to you.
Spock: We suffered 23 casualties in that attack, Captain.
Your computer account is overdrawn. Please reauthorize.
1 bulls, 3 cows
It's hard to get ivory in Africa, but in Alabama the Tuscaloosa.
Waste not, get your budget cut next year.
Old MacDonald had an agricultural real estate tax abatement.
Snow Day - stay home.
Save gas, don't eat beans.
The following is multiple choice question (with options) to answer.
A pile of iron will | [
"tug devices for locating directions",
"give false locations to planes",
"be a huge distraction",
"cause ships to crash"
] | A | if something contains a large amount of magnetic material then that something will attract magnets |
OpenBookQA | OpenBookQA-208 | everyday-chemistry, water, absorption
Fig. B is complete speculation on my part as I did not return to the home during Winter to observe it. However in Spring when I returned, all of the tubs had experienced a change in their appearance.
All the tubs were now dry again, presumably down to evaporation due to increasing weather temperatures. And therefore releasing all that moisture back into the building again!
Three of the tubs were largely unchanged with some noticable "caking" together of the salt into crumbly, grainy lumps which returned to normal looking salt grains when crushed.
The most profound change from the remaining tubs was as you see in Fig. C of the diagram.
The salt had actually accumulated on the walls of the tub as a fine sediment. This suggests that water had accumulated in large amounts in the tub and had in fact risen higher than the original depth of the dry salt grains! I'd estimate that the tub would have had to accumulate about 0.5kg of water in order for the water/salt solution to reach the depth indicated by the dry sediment.
The salt had solidified into a single, large mass. The volume seemed to have increased noticeably but the density had also decreased accordingly, so the salt had basically expanded in it's container and solidified. It was crumbly and brittle and some of it had been reduced to a very fine sediment.
The home is a single storey, about 12m x 4.5m x 2.5m in volume.
My questions then:
Is this a valid technique for capturing excess moisture over Winter?
Are my observations and presumptions reasonable... Is Fig. B what really happened?
What is the chemistry / physics process that caused the salt to be transformed from Fig. A to Fig. C?
How many times did the tubs cycle between states B and C? Was it a single cycle that lasted all of winter, or a daily cycle following ambient weather temperatures? I could not tell just by looking at C on the last day of the experiment. According to Transportation Information Service: Salt:
The following is multiple choice question (with options) to answer.
The water in the bowl was gone before the water | [
"on the tray",
"in the mug",
"on the plate",
"on the table"
] | B | as the surface area of a body of water increases , evaporation of that body of water will increase |
OpenBookQA | OpenBookQA-209 | 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.
A side effect of having a Husky as a pet is that when she sheds | [
"the dog enjoys being washed out",
"washing all the fur is easy",
"it takes hours to vacuum all of the fur",
"the fur is still attached to the skin"
] | C | shedding is when an animal loses hair |
OpenBookQA | OpenBookQA-210 | newtonian-mechanics, reference-frames, acceleration
It seems to me that the answers to your questions all depend on how one defines the "feeling of weight".
There seems to be general agreement that feeling "weightless" is a feeling associated with the absence of any contact forces on the body, as in the case of free fall. It seems to me that whether or not the presence of any contact force, in any direction on the body, in and of itself is associated with the feeling of weight would depend on just what one means by the "feeling of weight".
The professors's first example of hanging from a string involves a contact force pulling upwards on the body. He said that would give a person a sensation of weight. But it's a different feeling then standing on the ground experiencing a contact force acting upwards on your feet, which I think is more commonly associated with the perception of weight.
Ride a roller coaster and you experience contact forces of various magnitudes and directions on various parts of your body by the structure that restrains you. Do we consider all these contact forces as equivalent to the sensation of weight? If we define the feeling of weight as the feeling associated with any contact force, which the professor seems to be saying with the first example, then I suppose the answer would be yes. As for me, I'm not so sure.
Hope this helps.
The following is multiple choice question (with options) to answer.
An example of feeling | [
"Water sitting in front of me",
"My pants against my skin",
"Plants in the sun",
"The TV turned on"
] | B | feeling is when an living thing senses through touch |
OpenBookQA | OpenBookQA-211 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
Some fields house incredible creatures such as | [
"large rabbits",
"lions",
"wolves",
"mackerel"
] | A | some hares live in fields |
OpenBookQA | OpenBookQA-212 | power-engineering
Title: Why are hydropower plants always wheel-shaped and not flat? Question:
Why are there no flat power generators like in the picture below, that work on the surface of shallow, but steadily flowing rivers ? (As a floating micropower plant.)
The picture shows a conveyer belt with vanes/blades(?) attached to it. The water flow moves the conveyer belt. A generator could be attached to the front and back "wheel" of the belt.
Here's a video of something similar. I would just build it on a larger river.
Why would I ask this?
There are much more flat rivers than waterfall-like structures on this planet. Using them looks like a much more non-nature-inversive, cheap solution. Having a longer surface should supply better drag by flowing water. When you want to solve a problem, the best start is to look at previous attempts. To provide some perspective, I'm doing that for you now. You are not looking at a typical hydro power plant where a dam provides a high head, and the flow is ducted onto a a francis or pelton turbine. You are describing a microhydropower installation with a floating turbine.
Floating hydrpower allows capturing some power without building a dam. The turbine could be placed in or near the middle of the river, where the current is fastest. An installation with a damn will always harvest vastly more power from the same river.
Before electrical power transmission became widespread, there used to be boat mills - workshops with machinery driven by water wheels, placed on boats.
(Boat mill in Servia, 1900, Image from lowtechmagazine page on boat mills)
Improvised versions have also been used for electricity generation.
Floating hydro power is, AFAICT, an ongoing area of developement. The two most common turbine shapes appear to be a propeller hanging from buoys:
(Image source)
... Or some sort of flat paddle wheel:
Vertical axis turbines also exist.
I think Kamran explains quite well why a propeller or a paddle wheel is used, rather than a conveyor belt. I will just add this: Look at the water wheel in the direction of flow: You want to maximise area here.
The following is multiple choice question (with options) to answer.
Which of these items must be combined with a river to produce power? | [
"chocolat",
"ice",
"snow",
"concrete"
] | D | hydropower requires damming a river |
OpenBookQA | OpenBookQA-213 | In the case where the contestant opens a door other A, not knowing if the prize is behind that door, we do not know in advance that door B would not reveal the prize. The chance that the door B reveals the prize is much lower in the case where the door A is the prize door than in the case where it is not (probability $0$ versus $\frac12$); so the fact that B is not a prize door tells us that the probability the prize is behind door A is greater than we would have estimated previously. In fact, the probability the prize is behind door A increases from $\frac13$ to $\frac12$. The probability that the prize is behind door C also increases from $\frac13$ to $\frac12$.
The following is multiple choice question (with options) to answer.
You can let someone know you are at the door thanks to a | [
"lemonade",
"cars",
"grass.",
"power plant"
] | D | a doorbell converts electrical energy into sound |
OpenBookQA | OpenBookQA-214 | zoology, ecology, diet, predation
Cheetahs have been reported to suffer from intraguild competition by lions Panthera leo, spotted hyenas Crocuta crocuta and occasionally leopards Panthera pardus. These larger predators represent a threat to the smaller-bodied cheetahs as they can affect their food intake by limiting access to high resource areas or kleptoparasitism (e.g. 10–12% of kills are kleptoparasitized in Serengeti National Park (SNP)), and reduce population sizes via increased cub mortality (e.g. 73% of cub mortality was due to predation in the SNP). In response, cheetahs often demonstrate avoidance behavior to minimize interactions with dominant carnivores , with spatial and temporal partitioning regarded as the principal behavioral mechanisms by which this is achieved. Accordingly, cheetahs have been described as a refugial species that seeks competition refuges within the landscape with low densities of lions and spotted hyenas.
Rostro-García S, Kamler JF, Hunter LT. To kill, stay or flee: the effects of lions and landscape factors on habitat and kill site selection of cheetahs in South Africa. PLoS One. 2015;10(2):e0117743. Published 2015 Feb 18. doi:10.1371/journal.pone.0117743
(removed the citations)
The definition of the terms used in the above citation:
Intraguild predation, or IGP, is the killing and sometimes eating of a potential competitor of a different species. This interaction represents a combination of predation and competition, because both species rely on the same prey resources and also benefit from preying upon one another. - Wikipedia
Kleptoparasitism, literally meaning parasitism by theft, is a form of resource acquisition where one animal takes resources from another. Although kleptoparasitism of food (i.e., kleptoparasitic foraging) is the best known example, the stolen resources may be food or another resource such as nesting materials. - Sciencedirect.com
The following is multiple choice question (with options) to answer.
When being pursued by a lion | [
"a ram will leap",
"a mouse will hide",
"a cheetah will fight",
"a giraffe will dash"
] | D | some animals move quickly to escape predators |
OpenBookQA | OpenBookQA-215 | thermodynamics, pressure, evaporation
Why can the oven temperature reach $350 {}^\circ\text{F}$ when the maximum temperature of steam at $1 \text{ atm}$ is $212{}^\circ\text{F}$? Is it because the air molecules are able to heat up beyond what the water molecules can? Or are both at the same temperature? 350 °F are 176 °C, which is well above the boiling point of water; Liquid water can not get hotter than 100 °C at 1 atm. However, gaseous water (Steam) can become much hotter.
The oven can only hold around 1 atm; at the point where it exceeds this pressure in the inside, the mixture of gases will stream out of it in the respective proportions.
So what will happen is that during the heating process, air will exit the oven. as more and more water evaporates, this air will contain more and more water (which you will probably see condensing above the oven) according to the increasing amount of gaseous water in the oven.
When the 350°F are reached and the water amount in the air will reach your 598 g/m³, there will be less air and water leaving the oven, as some of the water condenses back into the puddle on the tray, but as long as you keep the pressure constant by allowing the water to escape, this will be vanishingly less and most of it will escape the oven. As long as there is liquid water on the tray, this water will have 100 °C, the air/water mixture in the oven will have 350 °F and the amount of gaseous water in the oven will be around 598g/m³. The water molecules in the air will approximately have the same kinetic energy as the air molecules; as most of the air molecules are heavier, the water will be accordingly faster. This will increase the heat conductivity in the oven, heating the food faster; if you shove your sourdough into the oven, water will condense on its surface too, giving the energy which was used to evaporate the water (which is a lot compared to similar substances!) to the loaf and heating it even faster, yielding a delicious crust. Enjoy it ;)
Edit; The density of 598g/m³ seems to be the density of pure steam at 100°C. Due to thermal expansion, I would expect it to be less at 180°C.
The following is multiple choice question (with options) to answer.
The ability that an oven has to turn ingredients into a moist cake come from its | [
"higher temps",
"arid environment",
"dark heat",
"spaciousness"
] | A | an oven is a source of heat |
OpenBookQA | OpenBookQA-216 | newtonian-mechanics, rotational-dynamics, everyday-life
Title: Why is it difficult to ride a bicycle with a partially inflated or deflated tyre? It is a common observation that riding a bicycle with an inflated tyre is easier than riding one with a deflated tyre but why is it so?
As per my knowledge in an ideal case of no deformation in tyre(when it is inflated) the torque of normal is zero(almost zero in non ideal case) about the axis of rotation whereas in the deflated case the tyre gets deformed and the normal shifts to the front of the tyre and therefore there is a torque of the normal too that our muscles need to overcome.
Is what I thought right and is there any other reason too? There are several factors that may be taken in account, but the more important is the energy used deforming the tire.
Suppose a deflated tire. As you move forward and the tire rotates, the part of the tire that is starting to touch the ground has to be deformed (since the tire is flat). You have to use an important amount of energy for that. Note that the part of the tire that has just stopped touching the ground also has to be deformed, which recovers some energy. Nonetheless, not all energy is gained due to elastic hysteresis, so we have a net loss. That loss has to be even by the cyclist, which is why it is more difficult to ride a bike with flat tires.
Note that there are other factors that may influence this. I'm quoting Wikipedia here
Additional contributing factors include wheel diameter, speed, load on wheel, surface adhesion, sliding, and relative micro-sliding between the surfaces of contact. The losses due to hysteresis also depend strongly on the material properties of the wheel or tire and the surface.
You may want to read this article about rolling resistance. Here it suppose a solid (or perfectly inflated) tire and an elastic ground, but it is equivalent.
The following is multiple choice question (with options) to answer.
Why would happen if the screw was loose on a bicycle's tire? | [
"it would need to be repaired",
"you could tape it",
"it might fall off",
"it might get flat"
] | C | a bicycle contains screws |
OpenBookQA | OpenBookQA-217 | algorithms
In the comment you mention that the text states that they omit floors and ceilings. This is always wrong. You cannot "omit" stuff. It invalidates your entire reasoning. (Sometimes, however, you can use true inequalities to get rid of floors or ceilings: for example, $\lfloor x \rfloor \leq x$.)
Consider for example a divide-and-conquer algorithm which splits its input into two halves and performs some $O(n)$ processing. You often see its running time expressed as the recurrence
$$ T(n) = 2T(n/2) + O(n). $$
This is clearly wrong – what if $n$ is odd? What does $T(13.5)$ even mean? The argument has to be a positive integer! The real recurrence is probably more like
$$
T(n) = T(\lfloor n/2 \rfloor) + T(\lceil n/2 \rceil) + O(n).
$$
When the text states that they omit floors and ceilings, they are being sloppy. They allow themselves to do that since you can solve the true recurrence $T(n) = T(\lfloor n/2 \rfloor) + T(\lceil n/2 \rceil) + O(n)$ via the fake one $T(n) = 2T(n/2) + O(n)$, which should be interpreted as defining a function $T(n)$ for all positive values of $n$.
The following is multiple choice question (with options) to answer.
Why was my son-in-law required to add rugs or carpeting to his upstairs apartment when the ground floor wasn't? | [
"So it would look good then prospective renters took a tour",
"Because they didn't want him to scratch up the wood floors.",
"Because they didn't want the downstairs renters to be as likely to complain about noise",
"Because they didn't want to pay for carpeting themselves."
] | C | carpet absorbs sound |
OpenBookQA | OpenBookQA-218 | plate-tectonics, crust, mantle, cavern
Title: How likely are caverns inside the mantle? Almost everyone wrongly assumes that the Earth's mantle is liquid, but it isn't (only the outer core is). Is it possible then that there are hollow spaces within the mantle, similar to caves in the crust? What could they look like and up to how much of the mantle could be hollow? What might be inside mantle caverns? Would they be filled with gas or rather vacuum? It is extremely unlikely that any hollow volumes exist in the mantle.
The mantle is a convecting solid which can deform over long timescales. Let's assume that such a cavern did somehow form. Whatever it is filled it, would be of lower density than the surrounding rock. It would slowly rise upwards through the solid-yet-deformable mantle until it reaches a place where the rocks are brittle, not ductile. That place is the crust. And as you know, the crust is full of caverns and there is no problem with that.
The following is multiple choice question (with options) to answer.
the mantle is | [
"a level of our planet",
"the planet closest to ours",
"a kind of rock found on Earth",
"the deepest part of our planet"
] | A | the mantle is a layer of the Earth |
OpenBookQA | OpenBookQA-219 | homework, plant-physiology, plant-anatomy
and 'Vascular Plants = Winning! - Crash Course Biology #37'
https://youtu.be/h9oDTMXM7M8?t=373
[5] Osmosis (water compensating solutes) "In Da Club - Membranes & Transport: Crash Course Biology #5"
https://youtu.be/dPKvHrD1eS4?list=PL3EED4C1D684D3ADF&t=148
Ian (and dad <= all errors and approximations are his :) ).
The following is multiple choice question (with options) to answer.
Transpiration involves | [
"H2O traveling about a daffodil's system",
"pollen traveling about the plant's system",
"the production of new oxygen molecules",
"the production of new seedlings"
] | A | transpiration usually happens in the leaves of a plant |
OpenBookQA | OpenBookQA-220 | homework-and-exercises, optics, sun, earth, diffraction
Title: Application of diffraction problem! Here is a problem that I am working on, which is the applying the concepts of diffraction to the setting of the sun:
Air has a small, usually negligible index of refraction. It is 1.0002926. This causes the Sun to actually be below the horizon when it appears to be just on the verge of sinking below it.
Suppose you are on the sea-shore watching the Sun apparently sinking into the ocean. When only its upper tip is still visible, by what fraction of the diameter of the Sun is that tip actually already below the surface?
As an approximation, take the earth's atmosphere as being of uniform density out to a thickness of 8.600 km, beyond which there is no atmosphere. This means that, with the Earth's radius being 6400. km, your line of sight due West along the ocean surface to the horizon will intersect this "upper surface" of the atmosphere at about 331.9 km from your eye. (The diameter of the sun subtends 0.5000 degrees at your eye).
This is how I've attempted to model the problem, but I'm not sure if it's correct...
I'm not really sure how to approach this problem.... Can anyone please help me? Here is a picture that should help you approaching the problem:
(Needless to say, nothing is drawn to scale)
First, evaluate $\alpha$ (see picture). Then, derive $i$:
$i = 180 - 90 - \alpha$
Then, substitute into Snell's law and derive $i'$:
$i' = arcsin(n sin(i))$ where $n=1.0002926$
Then derive the angle $j$ (see the picture).
Don't forget to convert it to Sun diameters, that is, multiply with $2$, provided that the Sun diameter is $0.5$ degrees.
I get $0.34308205134$ degrees, that is, $68.62$% of the diametre.
Most important, when you have understood it, try to do it by yourself again.
Good luck!
The following is multiple choice question (with options) to answer.
A microscope can be placed against the sun and | [
"burn an ant in the light's path",
"Provide shade on a hot day",
"Take a close up picture of the ground",
"Show how many wrinkles I have on my skin"
] | A | refraction is when light bends |
OpenBookQA | OpenBookQA-221 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
one inherited characteristic of fur is it's | [
"value",
"hue",
"weight",
"length"
] | B | the coloration of fur is an inherited characteristic |
OpenBookQA | OpenBookQA-222 | 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 adaption is | [
"Eating tacos",
"wearing sunblock",
"Reading a book",
"Drinking water"
] | B | adaptation is when an organism develops a trait over time for survival |
OpenBookQA | OpenBookQA-223 | zoology
From Scripture's research: “. . . a live frog can actually be boiled without a
movement if the water is heated slowly enough; in one experiment, the
temperature was raised at the rate of 0.002 degrees Celsius per
second, and the frog was found dead at the end of 2.5 hours without
having moved."
According to Dr. Karl S. Kruszelnicki (Australian scientist): "[T]he numbers just don’t seem right. If the water comes to a boil,
that means a final temperature of 100 degrees Celsius. In that case,
the frog would have to have been put into the water at 82 degrees
Celsius. Surely, the frog would have died immediately."
According to Dr. Victor H. Hutchinson (Herpetologist and Zoology Professor at University of Oklahoma):
"The legend is entirely incorrect! The 'critical thermal maxima' of many species of frogs have been
determined by several investigators. In this procedure, the water in
which a frog is submerged is heated gradually at about 2 degrees
Fahrenheit per minute. As the temperature of the water is gradually
increased, the frog will eventually become more and more active in
attempts to escape the heated water. If the container size and
opening allow the frog to jump out, it will do so."
Whit Gibbons (University of Georgia) says that there is an important message behind the false legend:
So where does that leave us with the boiling frog as a metaphor for
the human response to economic change or environmental degradation?
Well, it's not true that you can induce a frog to willingly remain in
boiling water by starting it off in cold water. But that does not
diminish the truth of the message that the accumulation of
imperceptible changes can have a significant effect on the economy and
the environment. We need to be aware of what changes are occurring and
to respond to them in a timely fashion. The metaphor lies in the
frog's ability to escape from the container: if there's no way out,
then the frog's fate is a foregone conclusion.
The following is multiple choice question (with options) to answer.
If a snail is heated to the point of being burned, the snail will | [
"be discomforted",
"be energized",
"be hungry",
"be sad"
] | A | burning a living thing usually causes harm to that living thing |
OpenBookQA | OpenBookQA-224 | experimental-physics, water, fluid-statics
Title: Determine water level difference in two ponds I live near two ponds whose water levels appear to differ by a few feet. The ground is hard clay, so I don't think there's any underground water exchange between the ponds. The ponds are separated by about 30 feet of a bumpy terrain, with the bumps reaching a few feet above the "higher" water level. What is the cleverest way to determine the difference in water levels between these ponds? What comes to mind is to stick two poles (several feet high) at the water line in each pond, stretch a string between them, level the string with a bubble level and measure the distances between the string and the water level on each pole. Any other ideas? Fill a garden hose with water. Hold both ends closed, and walk to the "higher" pond. Have someone helping you hold the end of the hose under water.
Now walk to the other pond (still holding the end of the hose shut). Hold the hose near the surface of the pond - you should feel water pressing against your finger. Make a very small opening and observe the water coming out.
Now raise the hose slowly. At the point where the water stops flowing, the end of your hose is at the level of the higher pond.
Measuring the height difference is now trivial.
Incidentally - you mentioned that the ground between the two ponds was "bumpy". This raises the question of whether this bumpiness affects the result.
What we have here is a siphon: if the water is not flowing, the pressure at any point along the hose is simply given by the height of the point relative to the level of the body of water that the inlet of the hose is submerged in. In fact, the pressure will be
$$p = p_0 - \rho g h$$
Where $\rho$ is the density of water (usually 1000 kg/m3), $g$ is the gravitational acceleration (9.8 m/s2) and $h$ is the height above the pond level. As you can see, when $h$ becomes greater than 10 m the pressure will become negative: this means the water will boil (evaporate), creating a bubble in the hose. At that point, the relationship is no longer simple. On the other hand, if the hose goes through a valley, the local pressure will be higher - but this will not matter in the end.
The following is multiple choice question (with options) to answer.
In a bog, when water levels become low, | [
"bog animals may be thirsty",
"bog animals may search longer for nutrients",
"the bog produces more water",
"bog predators need more prey"
] | B | as available water in an environment decreases , the amount of available food in that environment will decrease |
OpenBookQA | OpenBookQA-225 | human-biology, cancer, medicine
Title: Why are only few cigarette smokers prone to cancer? It's tacit that only a few populace of smokers get cancer. What spares the others from it or what specifically cause cancer in those populace? See this Washington Post Article Cigarette smokers are most certainly prone to cancer. See Cecil Medicine, Chapter 183, on the epidemiology of cancer, exposure to tobacco is the most important environmental risk factor for cancer development, at least in the US:
Exposure to tobacco is the single largest cause of cancer in the United States... All forms of tobacco can cause cancer. Cigarette smoking causes cancer of the lip, oral cavity, nasal cavity, paranasal sinuses, pharynx (nasal, oral, and hypopharnyx), larynx, lung, esophagus (squamous cell and adenocarcinoma), stomach, colorectum, pancreas, liver, kidney (adenocarcinoma and renal pelvis), urinary bladder, uterine cervix, and myeloid leukemia.
Cancer may be identified or the cause of death in fewer smokers than might be expected, though, because smoking is an even greater risk factor for cardiovascular disease, and death due to cardiovascular disease.
Cancer is an unlikely phenomenon in an individual cell, but becomes more likely at the organism level, and even more likely over time. Though tobacco may be the most important environmental risk factor for cancer, age is actually a stronger predictor of cancer (see again, Cecil Chapter 183. Autopsy studies give us a quite remarkable example, this one shows incidental prostate cancer in nearly 60% of men over 80 who died from other causes. That figure is not out of the ordinary. Live long enough and you are likely to develop cancer.
Death due to heart disease may account for the lower than expected rates of cancer diagnoses and deaths in smokers. Nothing prevents cancer as well as dying from something else. And as discussed in the blog in the Washington Post you linked to, up to 2/3 of smokers die from smoking related causes
The following is multiple choice question (with options) to answer.
What contributes more, though less than some believe, to the lung damage caused by smoking? | [
"smoking less",
"switching to chewing",
"no filters",
"switching to e-cigs"
] | C | smoking causes direct damage to the lungs |
OpenBookQA | OpenBookQA-226 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
The below surface pebbles of the Snake River are of non rough edges because of? | [
"smoothness",
"fish movement",
"river movement",
"rough rocks"
] | C | contact between rocks over long periods of time causes rocks to smooth |
OpenBookQA | OpenBookQA-227 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
There are producers that exist in the food chain, and they basically | [
"are mainly creatures like deer",
"require photosynthesis to survive",
"produce a thing called chlorophyll",
"make good money at work"
] | B | producer is a kind of role in the food chain process |
OpenBookQA | OpenBookQA-228 | 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.
Pollution is caused by | [
"reusing cloth baby diapers",
"recycling plastic water bottles",
"using all natural household cleaners",
"prescription medicine being put down sink drains"
] | D | pollution is a source of pollutants |
OpenBookQA | OpenBookQA-229 | algorithm, go, concurrency, dining-philosophers
// reserve a slot in the channel for eating
// if channel buffer is full, this is blocked until channel space is released
pPhilo.host.requestChannel <- pPhilo
pPhilo.numEat++
fmt.Printf("starting to eat %d for %d time\n", pPhilo.idx, pPhilo.numEat)
time.Sleep(time.Millisecond)
fmt.Printf("finishing eating %d for %d time\n", pPhilo.idx, pPhilo.numEat)
pPhilo.rightCS.mu.Unlock()
pPhilo.leftCS.mu.Unlock()
wg.Done()
}
}
func main() {
var wg sync.WaitGroup
host := Host{
eatingChannel: make(chan *Philo, numEatingPhilo),
requestChannel: make(chan *Philo),
quitChannel: make(chan int),
eatingPhilos: make(map[int]bool),
}
CSticks := make([]*ChopS, numCS)
for i := 0; i < numCS; i++ {
CSticks[i] = new(ChopS)
}
philos := make([]*Philo, numPhilo)
for i := 0; i < numPhilo; i++ {
philos[i] = &Philo{idx: i + 1, numEat: 0, leftCS: CSticks[i], rightCS: CSticks[(i+1)%5], host: &host}
}
go host.manage()
wg.Add(numPhilo * eatTimes)
for i := 0; i < numPhilo; i++ {
go philos[i].eat(&wg)
}
wg.Wait()
host.quitChannel <- 1
}
The following is multiple choice question (with options) to answer.
I have to plug in a processor of food because it | [
"Is used for grinding metal",
"is an oil machine",
"is an electric Motor",
"is a battery operated machine"
] | C | an electric car contains an electric motor |
OpenBookQA | OpenBookQA-230 | genetics, vision
Females who are heterozygous for red and green pigment genes that encode three
spectrally distinct photopigments have the potential for enhanced color vision, as they are effectively tetrachromats (Deeb, 2005, Neitz et al., 1991). However, sensitive color-contrast testing on 43 tetrachromats has revealed that most of these females have no deviating color-discrimination whatsoever. 8 subjects showed relatively small effects, while only one showed a clear increased sensitivity in a narrow range of frequencies. It is believed that the human visual system is not plastic enough to cope with the extra spectral input. In fact, in the group there was an overall increase in error rates on some color tests (pseudoisochromatic plates, and Nagel anomaloscope color matching) (Jordan & Mollon, 1993).
In New World Monkeys, however, the situation is different. Squirrel monkeys are basically a dichromatic species, but two-thirds of the females are heterozygous, and gain trichromatic vision by expressing two of three possible alleles coding for pigments in the middle- to long-wave range of the spectrum. X-chromosome inactivation serves to segregate the alternative allelic products in different subsets of cones. The visual system of the heterozygous female is apparently plastic enough to take advantage of the presence of three classes of cone, because heterozygous monkeys have enhanced color selectivity in the red-green range that are impossible for all males and for homozygous females. This advantage perhaps enables the heterozygote to judge better the ripeness of fruit, or to find fruit or conspecifics (Jordan & Mollon, 1993).
Note that the emergence of trichromacy in humans and some other primates was the result of the red/green gene duplication. Trichromacy in primates was evolutionary selected for likely because of the enhanced capability to discern (ripe) fruits (Lucas et al., 2003). It has nothing to do with sex-differences, because not many human females benefit from tetrachromacy in terms of enhanced color vision.
References
- Deeb, Clin Genet (2005); 67: 369–377
- Jordan & Mollon, Vis Res (1993); 33(11): 1495-1508
The following is multiple choice question (with options) to answer.
The size of eyes matter relevant to sight and sight ability, given that | [
"elephants see better than ants",
"wolves see better than giraffe",
"people see better than dogs",
"dogs see better than cats"
] | A | as the size of the eyes of an animal increases , the ability of that animal to see will usually increase |
OpenBookQA | OpenBookQA-231 | physiology, ichthyology
Salmon use to deal with the NaCl fluxes driven by the gradients between the salmon and its surroundings. In their gill epithelial cells, salmon have a special enzyme that hydrolyzes ATP and uses the released energy to actively transport both Na+ and Cl- against their concentration gradients. In the ocean, these Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the salmon's blood into the salt water flowing over the gills, thereby causing NaCl to be lost to the water and offsetting the continuous influx of NaCl. In fresh water, these same Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the water flowing over the gills and into the salmon's blood, thereby offsetting the continuous diffusion-driven loss of NaCl that the salmon is subject to in fresh water habitats with their vanishingly low NaCl concentrations.
Reference
Reference
The following is multiple choice question (with options) to answer.
The reason that ducks are such excellent swimmers is because | [
"ducks have a space between their toes",
"ducks are buoyant and resilient",
"ducks have wide feet",
"ducks have extra foot skin"
] | D | webbed feet are used for moving faster through water by aquatic animals |
OpenBookQA | OpenBookQA-232 | materials
The image is a modified version of an image found at www.geology.um.maine.edu. Original credit: Passchier and Trouw, pg 33 (2005).
The following is multiple choice question (with options) to answer.
Some minerals originated from a material that was | [
"hard",
"clear",
"light",
"far away"
] | D | minerals are formed from magma cooling |
OpenBookQA | OpenBookQA-233 | rainfall, tropical-cyclone
But perhaps to visualize the scale involved in creating a catastrophic largescale flood such as Harvey, this plot, created from a base image from pivotalweather.com, best shows the conditions around the storm (from the GFS model):
Basically the atmosphere of the entire Gulf (and beyond) is being pumped into the southeast Texas area. So although the air can only hold a couple inches (some 50 mm) of water, and evaporation rates are typically only a fraction of an inch (several mm) per day... bringing that together from such a large source region, and focusing it down into one small area... can lead to these awful extreme deluges.
Addendum: It should also be highlighted that the NHC adds in their report on Harvey that rising motion was also enhanced by a front which had stalled in the area. Air being advected in by Harvey's flow would naturally rise over that layer of cooler air when moving inland (a process called isentropic lift), which proves particularly efficient in condensing out the (abundant) moisture en masse into rainfall. Most substantial regional floods require similar existence of a significant broad lifting mechanisms overlaid with such a relentless inflow of warm, moist air.
The following is multiple choice question (with options) to answer.
Heavy rains cause flooding which | [
"soak fields",
"create dams",
"feed fish",
"ruin crops"
] | D | heavy rains cause flooding |
OpenBookQA | OpenBookQA-234 | botany, anatomy, plant-anatomy
Title: Plant anatomy, what are these stem like filaments growing under the flower The picture below shows what I am talking about. Each flower has one and I am just wondering what they are? Looking at this, it looks like a spur. A quite overbreed one, though.
The following is multiple choice question (with options) to answer.
Stems are to flowers as | [
"dogs are to cats",
"cows are to cud",
"bees are to pollen",
"silos are to grains"
] | D | a stem is used to store water by some plants |
OpenBookQA | OpenBookQA-235 | evolution, zoology, eyes
Title: Do other animals suffer from myopia or hypermetropia? Mammals have eyes similar to humas and many other animals like octopuses have a lens in the eye. So do they have such eye defects? If yes, how do they overcome it? Do they feel selection pressure against them in such cases?
do they have such eye defects?
Yes, eye defect is not specific to humans of course. Cases of eye defect are very common in animals. It is most often witnessed in domestic animals and they are the ones we observe the most (see The physiology of domestic animals)
Eye defects have typically been observed in tree shrews, monkeys (incl. macaques), cats, dogs, horses, rats, elephant and a Cape buffalo.
You should have a look at the wikipedia article Myopia in animals
howw do they overcome it?
They don't wear glasses obviously!
Humans uses the sense of vision a lot. Many animals uses smell (and taste), hearing or touch much more than humans do. For such non-visual animal, having a slight eye defect is not too big of a deal.
Do they feel selection pressure against them in such cases?
That is a bit of an awkward question. Nobody can feel a selection pressure on themselves. A selection pressure is a fitness differential associated with genotypes. A selection pressure is therefore defined at the population level. There is no such thing as a fitness pressure against a single individual.
Let me rephrase this last question to something that makes more sense. I am not sure I will address the specific question that was of interest to you though.
Are non-humans animals that have an eye defect aware that they have an eye defect?
It is unlikely that any animal would have the cognitive abilities to notice that they see more poorly than another animal of the same species. Doing so, would at least require having the ToM and only few species do.
The following is multiple choice question (with options) to answer.
when an animal's eyes grow, what happens | [
"they see more",
"they close them",
"they get dry",
"they pop out"
] | A | as the size of the eyes of an animal increases , the ability of that animal to see will usually increase |
OpenBookQA | OpenBookQA-236 | atmospheric-science, spectroscopy, plasma-physics, solar-wind
Title: Colors of the Aurora I've seen several web pages that attempt to explain the colours of the aurora but they seem to gloss over or leave out certain details, so I'm still confused. For example, this page explains it in terms of what elements high energy particles from the sun hit at what altitudes, but doesn't explain what determines what altitude a particle is more likely to hit what element. For instance, it says that the common green colour is due to ionizing oxygen and the purple colour is from nitrogen, but there's a lot more nitrogen in the atmosphere than oxygen so why doesn't purple predominate? Does the relative concentration of different gasses change with altitude?
I just returned from Greenland where we saw spectacular Northern Lights, mostly green, some purple. Yes the atmospheric composition varies with altitude. Although $N_2$ dominates at ground level, atomic oxygen dominates between 200-450km, reaching 85% by volume.
Courtesy of wikipedia. Attribution : Amaurea - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=71001656
The explanation that different colours are produced by different species which are dominant at different altitutes is suggested by the web-page which you linked :
The main factor in determining the colours of any given display is the altitude at which the solar particles collide with our atmosphere. Different gases prevail at different altitudes and in varying concentrations and it is the collision which “excites” these gases that determines the colour of the Aurora.
The following is multiple choice question (with options) to answer.
Environments which are covered in snow are often white as a result of said snow and what other factor? | [
"conditions which allow little if any heat to be produced or stored",
"temperatures that are colder than a tropical environment",
"cool air that flows in a circular pattern",
"wind chill that meets warm fronts on occasion"
] | A | cold environments are usually white in color from being covered in snow |
OpenBookQA | OpenBookQA-237 | biochemistry, gas-laws
Title: What is the state of aggregation (gas, liquid) of oxygen in blood? Atmospheric oxygen is in O2 and a gas. Then we inhale the air, our efficient lungs do the magic to filter out the oxygen and push them into the blood stream.
When we say hemo and globin transport the oxygen using the iron ions. In what state oxygen is transported in the blood? as a gas or a liquid or an ion? It is hard for me to conceive of the idea that oxygen would be in gaseous form in the blood. "GAS in blood?" e.g. Arterial Blood Gas Test
Also, how does the lungs convert the gas into something that is compatible to be in blood?
References:
Amount of Oxygen in the Blood Regarding the state of oxygen in blood: It is in solution in the blood plasma (which mostly consists of water), in the form of single molecules. Think of water which you leave exposed to air: carbon dioxide will be captured and dissolved (along with the other gases in air), but these molecules are not gaseous or liquid, but rather "in solution", which is different from the "classical" states.
Back to oxygen: As your reference already states, most of the oxygen in solution will bind to hemoglobin. The actual state of oxygen in that complex has been debated, but it is believed to be reduced by the hemoglobin iron to the superoxide anion, coordinated to Fe$^{3+}$. See Wikipedia on this.
Also, the lungs do not "convert" the atmospheric oxygen to anything, they rather allow, due to their very large surface area, the quick exchange of oxygen/carbon dioxide in solution and in the air.
The following is multiple choice question (with options) to answer.
Blood absorbs oxygen in the | [
"both lower limbs of the body",
"organs that develop during childhood",
"nasal bones projecting above the mouth",
"inner canals of the ear"
] | B | blood absorbs oxygen in the lungs |
OpenBookQA | OpenBookQA-238 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
For a hungry hawk chasing a mouse, if the mouse darts away, the hawk must | [
"adjust speed",
"run after it",
"find other prey",
"take a break"
] | A | if an organism 's prey moves quickly then that organism may need to move quickly to catch its prey |
OpenBookQA | OpenBookQA-239 | java
}
return list;
}
public List<Mother> mothersWithTwins() {
List<Mother> list = new ArrayList<>();
for (Mother mother : mothers) {
if (motherHasTwins(mother)) {
list.add(mother);
}
}
return list;
}
public boolean motherHasTwins(Mother mother) {
Set<LocalDate> set = new TreeSet<>();
for (Newborn newborn : mother.getList()) {
set.add(newborn.getBirthday());
}
return set.size() < mother.getList()
.size();
}
public static void main(String[] args) {
App app = new App();
app.buildRelation("src\\motherFile.txt", "src\\\\NewbornFile.txt");
System.out.println("Tallest daughter:");
System.out.println(app.getTallestNewborn(false));
System.out.println("\nTallest son:");
System.out.println(app.getTallestNewborn(true));
System.out.println("\nMost common date:");
System.out.println(app.mostCommonDate());
System.out.println("\nMothers over 25 Years old with childer heavier than 4000g;");
app.motherMoreThan()
.forEach(System.out::println);
System.out.println("\nDaughters that inherits their mother's name: ");
app.newbornWithMotherName()
.forEach(System.out::println);
System.out.println("\nMother that has twins:");
app.mothersWithTwins()
.forEach(System.out::println);
}
}
Is it the fastest way?
Probably not, though there's a lot to work on before performance considerations necessarily factor in.
Can it be minimized?
Yes!
Is the approach correct?
The following is multiple choice question (with options) to answer.
Mothers have many roles, one of which is | [
"gestating and birthing",
"making good dinner",
"creating fun activities",
"watching the babies"
] | A | a mother births offspring |
OpenBookQA | OpenBookQA-240 | design, bicycles
On a motorbike there are more control lines and critical electrical cables running to the bars, and these are bigger, stiffer, but not really any stronger, so they need protecting, both by restricting the movement and by sheathing them in ways that work better when restricted. Failure modes are likely to be more severe as well. Fairings (when present) on frame and forks have to be designed not to contact each other unexpectedly while doing their job with respect to airflow. Limiting the range of movement helps the designer here. The combination of fairings and far more controls on the handlebars means it would be harder to design a motorbike so everything was sensibly located, but the bars couldn't hit the tank for a large movement.
Note that it is possible to retrofit steering dampers to pedal bikes, which also limit the steering range. In the same way, bikes often aren't supplied with kickstands, but they may be retrofitted.
The following is multiple choice question (with options) to answer.
Small, usually red plastic squares are often placed on transporters such as bicycles in order to | [
"create light",
"show color",
"identify drivers",
"shine light"
] | D | a reflector is used to reflect light especially on vehicles |
OpenBookQA | OpenBookQA-241 | zoology, pathology, herpetology
Title: How do pet gecko lizards pose a health risk? Does having gecko lizards living in your house pose any health risk? If you're referring to keeping geckos as pets, like all reptiles, amphibians and birds, they come with a small but finite risk of contracting salmonellosis. Having said this, the infection is easy to avoid if you maintain basic hygiene.
On a personal note, I know dozens (perhaps hundreds) of people who keep or have kept reptiles as pets and have yet to meet anyone who contracted salmonellosis. Basically, if you wash your hands after touching the gecko, keep it away from food preparation areas and don't put the lizard in your mouth, you should be fine.
If you're talking about geckos living free in your home, as is common in many tropical places, I have never heard of any health risks associated with them. If anything, I would think that the geckos would reduce health risks by eating insects such as cockroaches and mosquitoes that are prominent disease carriers.
The following is multiple choice question (with options) to answer.
If a lizard is unable to obtain sufficient nutrients in a period of time, the resulting effect may be | [
"ceased existence",
"moving slowly",
"feeling cold",
"finding food"
] | A | an animal needs to eat food for nutrients |
OpenBookQA | OpenBookQA-242 | That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The total that we have observed the opossums to eat is 5% x 150 + 10% x 120 + 20% x 120 = 43.5 plants.
They eat 5% large, which a corresponding fraction of 5% x 150 / (5% x 150 + 10% x 120 + 20% x 120) = 17%
They eat 10% low for 10% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 28%
They eat 20% hybrid for 20% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 55%.
Checking... yes the total is 100%.
What we see is that the opossums prefer hybrid by far.
Small blueberries are their second choice.
Last edited:
#### anemone
##### MHB POTW Director
Staff member
Hi anemone!
What do you mean by the symbol E?
Anyway, you've found that the opossums eat 45.8% large and 54.2% small for a total of 100%.
But... what happened to the hybrid blueberries?
By the symbol E, I meant the blueberries (all 3 types of them) that are eaten by opossums...
That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The following is multiple choice question (with options) to answer.
A bunny wants to eat strawberries, but it is unable to find any. However, the bunny finds a patch of small white buds. If the rabbit waits a while | [
"there will be extra bees",
"there will be green flowers",
"there will be eight rabbits",
"there will be berries there"
] | D | flowers are a source of fruit |
OpenBookQA | OpenBookQA-243 | kalman-filters
2 \left(x_{k+1} - x_k \right) /dt - \dot{x}_k\end{array}
\right)
\end{align*}
$$
As you can see, the value for the speed is given by exactly the formula you were proposing to use for the speed estimate. So although you couldn't see any kind of calculation $(x_k-x_{k-1})/dt$ for speed, in fact it is hidden in there after all.
The following is multiple choice question (with options) to answer.
We can calculate a speed if we know a number of | [
"gallons",
"millimeters",
"dollars",
"pounds"
] | B | calculating speed requires knowing distance travelled |
OpenBookQA | OpenBookQA-244 | energy, collision
Again, imagine two extended masses speeding towards each other. However, now we shall assume these masses to have an internal structure, to be composited of many small atoms, placed in a relatively rigid grid. Furthermore assume that in the beginning, there is no temperature, that is $T = 0$. This means that the atoms in each of the masses all move in the same direction and don’t vibrate at all.
What happens is that these atoms (at least in our model) interact with each other very similarly to the particles in the first example.
Note that we now have many, many different particles (about $10^{24}$ rather than two) and not just one, but three dimensions. Therefore, if the two large masses collide, these small atoms will bounce off each other in many different directions (like balls bouncing off each other in different directions depending on the exact angle of collision). These ‘random’ movements of the atoms are caught by the other atoms around them, so in effect, they don’t run off everywhere but merely start vibrating in place. And this vibration is heat.
Of course, the model can be expanded further: We could think of some atoms gaining so much momentum from the impact that they flew out of the grid and into space (the masses being damaged) or that the grid is somehow changed and the atoms moved further towards each other (the masses being deformed).
The key point, however, is that inelastic collisions are usually macroscopic rather than microscopic effects relying on the internal structure of the masses involved.
The following is multiple choice question (with options) to answer.
When any two object strike with each other, the molecules of the outer of the two objects coming in contact could | [
"rot",
"quake",
"smoke",
"freeze"
] | B | tapping two objects together causes the particles in those objects to vibrate |
OpenBookQA | OpenBookQA-245 | fluid-mechanics, thermodynamics, heat-transfer
Water will only condense when moist air is cooled below its dew point. The amount of water the air can store is not important to us in this case; just when it is at the dew point.
This means that in order for this system to produce any water, the night temperature must be less than the noon dew point. The final temp will be the noon dew point because any warmer and water will not condense, it will evaporate. As such, if it continues past that point it will evaporate all the water it gained.
To calculate how much water will be produced you will use something like:
Rock_Specific_Heat * Rock Mass * ΔT(night_temp to noon_dewpoint) =
The following is multiple choice question (with options) to answer.
Condensation over night | [
"leads to extremely dry conditions",
"can lead to slippery grass",
"causes plants to wilt and die",
"causes black ice on bridges"
] | B | dew is formed when water vapor condenses over night |
OpenBookQA | OpenBookQA-246 | thermodynamics
Title: Thermodynamic equilibrium in a room , in a real situation In my class about 50 students were seated in a room. The room was medium sized and it had 2 AC, one in the front and one at the back.
The teacher was feeling cold so he switched off the front AC while leaving the back one on. I thought it would not matter because ultimately an AC maintains the temperature and thermodynamic Equilibrium would be attained and he would still feel cold.(They were the powerful overhead type)
But that didn't happen. While at the back it was very cold , the front was at a normal temperature.
But why is it so?? Why was thermodynamic equilibrium not attained. Even if there was warm air was present in front , it should rush back and cool air should move to the front and he should still feel cold....
There are no windows and only a single door. Since more than one AC was used, the room should surely not be big enough for a single AC. The AC at the back throws out cool air , buy you are neglecting the 50 radiatior (humans) sitting in the class. By the time the air reaches till the front it gets warmer. There is a constant gradient of temperature that is present and is maintained by the humans acting as a source and the AC as a potential sink.
The following is multiple choice question (with options) to answer.
In a warm room, it is likely that the source of heat is | [
"a series of metal pipes along a wall",
"a small ceiling fan",
"a stove which is turned off",
"a pile of boxes"
] | A | a radiator is a source of heat |
OpenBookQA | OpenBookQA-247 | mycology, microscopy, parasitology
Cross sections of leaves (hold between two thin pieces of polystyrene or cork and slice gently with a new single-edge razor blade or craft knife). . These will show the internal structure of the leaves - veins (xylem, phloem), cells etc. You can also use clear nailpolish to paint on the surface of a leaf (try the underside), then peel off and look at under the microscope - this should let you see the pores (called stomata) in detail, they look like pairs of lips usually. The fine tissue skin (not the brown bit, it's a very thin wet translucent bit) of an onion also looks pretty nice. Moss leaves also are fun to look at.
Along with mosses - take some dry moss, let it sit in water for 30 min or so and then squeeze out - you'll hopefully find tardigrades
Edited to add:
With respect to parasites in faeces; this requires a bit of expertise to get good at. There is a lot of matter in faeces and parasites are generally low abundance. Unless you know a host is infected and are willing to mix faeces with water, filter and do a bunch of screening, you might not find any actual parasites, though you might see things that look, to the untrained eye, like parasites but are really just debris. You also run a significant chance of infecting yourself with something, be it parasitic, bacterial or viral.
The following is multiple choice question (with options) to answer.
Wax is on some plant leaves for what purpose? | [
"stay moist for warm weather",
"keep water available for predators",
"creation of toxins in the cells",
"keep the ongoing hydration"
] | D | waxy leaves are used for storing water by some plants |
OpenBookQA | OpenBookQA-248 | biochemistry, neuroscience, neurophysiology, vision, eyes
*Personally, I find it hard to grasp just how large the difference in Illuminance (and hence photon numbers) is for example between day and night. See here for a comparison. As you can see, our visual system has to deal with an enormous dynamical range of illuminance. The fact that we usually don't even think about these differences in light intensities in everday live is testament to how fantastic our visual system is in dynamically adapting to the huge differences in input.
The following is multiple choice question (with options) to answer.
Lightness may be seen reflected more clearly and brighter off of lighter colored objects, so an example would be | [
"a mirror is unable to be dark",
"phone screens are barely reflective",
"a lilac door is easily seen",
"a black door is easily seen"
] | C | as lightness in color of an object increases , the ability of that object to reflect light will increase |
OpenBookQA | OpenBookQA-249 | optics, visible-light, reflection, refraction
As apparently we are able to see blue and weak, but clear violet stripe in the rainbow, my understanding is wrong. So why don't we get red, yellow, green and blue light in it as well? Why do we see spectrum as if we were using prism, not the "cumulative spectrum"? With the addition of some good diagrams I think I now understand your question.
This diagram does not show a key feature of the reflections.
The intensity of the reflected rays varies and so you do not observe a uniform cone of reflected light.
Here is a gif animation to show you what I mean.
[Individual images were taken from an Atmospheric Optics webpage and combined to produce a gif file.]
Parallel rays are coming in at the top of a water droplet and refracted, reflected and refracted again to emerge from the bottom half of the drop.
What you should note is that for a given range of impact parameters of the incident rays the highest concentration of emergent rays occurs occurs around an angle of $137.5^\circ$, ie that is where the emergent light is brightest and light from around that angle swamps the light from that emerging at other angles.
So you diagram should show a high intensity of red light around a particular direction and and much lower elsewhere.
Here is a ray diagram to illustrate the "bunching" of light rays along a particular direction.
The following is multiple choice question (with options) to answer.
What can show how a rainbow is formed by refraction of light by splitting light into all different colors? | [
"watching sunlight bounce off a mirror",
"shining a flashlight on a gem",
"shining a flashlight at a mirror",
"looking at a freshly formed diamond"
] | B | a rainbow is formed by refraction of light by splitting light into all different colors |
OpenBookQA | OpenBookQA-250 | genetics
I will discuss a few concepts and slowly introduce the concept of heritability in both senses.
Phenotypic trait
The phenotype is the consequence of the genotype on the world. In brief, a phenotypic trait is any trait that an individual is made of!
Quantitative trait
A quantitative trait is any trait that you can measure and ordinate, that is any trait that you can measure with numbers. For example, height is a quantitative trait as you can say that individual A is taller than individual B which is itself taller that individual C.
Variance of a quantitative trait
In a population, different individuals can have different values for a given phenotypic trait $x$. Because we are talking about quantitative traits we can calculate the variance of the trait in the population. Let's call this variance $V_P$ such as
$$V_P=\frac{1}{N}\sum_i (x_i - \bar x)^2$$
In the above equation, $x_i$ is the value of the phenotypic trait $x$ of individual $i$. $N$ is the population size (there are $N$ individuals in the population) and $\bar x$ is the average phenotypic trait $x$ in the population.
$$\bar x = \frac{1}{N}\sum_i x_i$$
What is causing phenotypic variance
Why would a population display any phenotypic variance? Why wouldn't we just look exactly the same? What explains these differences?
For some traits, we see very little variance. To consider the example the OP gave in the post, the number of arms in the human population shows very little variance. However, there is quite a bit of variance in terms of the number of IQ, in terms of height or of weight.
There are two (main) sources of variance that are underlying this phenotypic variance. The first one is the genetic variance and the second one is the environmental variance. We will call the genetic variance $V_G$ and the environment variance $V_E$.
The following is multiple choice question (with options) to answer.
Which of these animal traits is generally determined by environmental factors rather than heredity? | [
"eye color",
"height",
"hair length",
"number of chromosomes"
] | C | the length of the hair of an animal is an acquired characteristic |
OpenBookQA | OpenBookQA-251 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
Bees are attracted to | [
"a sugar rich liquid plants produce",
"the scent of flower stamens",
"a oxygen rich liquid plants produce",
"the magnetic field flowers give off"
] | A | nectar is used for attracting pollinators by plants |
OpenBookQA | OpenBookQA-252 | python, interview-questions, simulation
def breed_animals(self):
babies = []
male_available = False
for animal in self.population:
if animal.gender == 2 and animal.age >= animal.minimum_breeding_age:
#check for at least one male of age
male_available = True
break
for animal in self.population:
if animal.gender == 1 and animal.living:
if animal.pregnant['pregnant'] and (animal.pregnant['months'] >= animal.gestation_period):
animal.pregnant = {'pregnant': False, 'months': 0}
new_animal = Animal(
animal.species,
animal.monthly_food_consumption,
animal.monthly_water_consumption,
animal.life_span_years,
animal.minimum_breeding_age_years,
animal.maximum_breeding_age_years,
animal.gestation_period,
animal.minimum_temperature,
animal.maximum_temperature
)
babies.append(new_animal)
elif (not animal.pregnant['pregnant'] and
animal.minimum_breeding_age <= animal.age < animal.maximum_breeding_age):
fertility = animal.fertility_rate
if (self.food_supply < animal.monthly_food_consumption or
self.water_supply < animal.monthly_water_consumption):
fertility *= .005 # reduces fertility rate if insuff. resources
if dice_roller(fertility):
animal.pregnant['pregnant'] = True
self.population += babies
The following is multiple choice question (with options) to answer.
If an animal is living, then | [
"it is taking in air",
"it tries to breathe",
"it is using water",
"it needs to reproduce"
] | A | all animals breathe |
OpenBookQA | OpenBookQA-253 | pathology
Title: Are all diseases caused by organisms (microorganisms)? Are there other causes? Or is it correct to say that all diseases are in fact caused by organisms (microorganisms)? It is not correct to say that all diseases are caused by foreign organisms. Counterexamples are:
Cancer is caused by random genetic mutations in the cells of our body. The mutations can be caused by many factors such as ionizing radiation, smoking, chemical toxins etc.
Diseases such as stroke or heart attack are caused by blood clots blocking the blood flow to essential organs.
Autoimmune diseases are caused by the immune system falsely recognizing cells of the body as foreign and attacking that tissue leading to a wide variety of symptoms.
Alzheimer's disease is caused by chronic neurodegeneration, meaning that the cells in the brain die. The causes are not quite understood but as Alzheimer's usually appears late in life it is likely related to ageing. Also, it is known that some genetic defects can lead to early-onset Alzheimers.
Prion proteins can cause diseases such as Creutzfeldt–Jakob disease also known as mad-cow disease.
Hereditary diseases such as early-onset Alzheimers or ALS are cause by gene defects inherited from the parents.
Toxins can cause chronic diseases such as lead poisoning.
The list probably goes on...
Please note that the first two on the list are the most common cause of death in developed countries.
The following is multiple choice question (with options) to answer.
What does harming an organism cause? | [
"change in appearance",
"nothing",
"population increase",
"population decrease"
] | D | harming an animal species causes that animal 's population to decrease |
OpenBookQA | OpenBookQA-254 | hematology, cardiology, blood-circulation, red-blood-cell, veins
Veins are not like impermeable rubber tubes, they are 'living' structures requiring, like all cells, Oxygen and glucose to survive. Smaller veins get the O2 from diffusion, while the larger veins need help from vasa vasorum, small blood bessels that bring blood to the walls of the veins.
The innermost cells lining veins are epithelial cells. They also line valves.
In the picture you posted, blood is not circulating well behind valves. The cause of hypoxia is that epithelial cells are continually removing O2 from the blood.
When enough O2 is removed to cause hypoxia, the endothelial cells may become damaged by the lack of O2, causing inflammation and (possibly) potentiating clot formation.
Activation of endothelial cells by hypoxia or possibly inflammatory stimuli would lead to surface expression of adhesion receptors that facilitate the binding of circulating leukocytes and microvesicles. Subsequent activation of the leukocytes induces expression of the potent procoagulant protein tissue factor that triggers thrombosis.
Mackman N. (2012). New insights into the mechanisms of venous thrombosis. The Journal of clinical investigation, 122(7), 2331–2336. doi:10.1172/JCI60229
The following is multiple choice question (with options) to answer.
Veins carry blood which means that they | [
"lack enough fluid to grow",
"cart essential substances around",
"are unessential for health",
"keep the body healthy"
] | B | veins transport nutrients throughout the body |
OpenBookQA | OpenBookQA-255 | • Thanks, I realise now that the sufficiency and necessity claims were about the stronger claim, not the original claim as I had mistakenly thought. Yes, your explanation of sufficiency is clear now (certainly for edges with distinct weights, I haven't thought carefully about the case where equal-weight edges are allowed), and the other direction is also clear, as is the fact that the inital claim implies greedy never produces a greater sum. – j_random_hacker Mar 11 at 5:02
The following is multiple choice question (with options) to answer.
A source of something supplies that something, like how | [
"clouds are a cloud source",
"ponds are a moisture source",
"air is a air source",
"fish are a fish source"
] | B | a source of something supplies that something |
OpenBookQA | OpenBookQA-256 | optics, electromagnetic-radiation, photons, quantum-electrodynamics, refraction
Which is why you can see through a window.
But if you use ground glass, the surface is no longer flat but has been modified to change the direction - and this results in the image behind the glass becoming fuzzy. The same principle exists in the glass used in many showers (original image from Victoria Elizabeth Barnes's posts on bathroom remodeling:
The following is multiple choice question (with options) to answer.
If you breathe out, especially in the vicinity of clear glass, you may witness | [
"your breath is air",
"your breath is dry",
"your breath beading up",
"your breath smells bad"
] | C | breath contains water vapor |
OpenBookQA | OpenBookQA-257 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
The bear in the wild needs to find other animals to feast. | [
"they never kill",
"they only eat",
"they are docile",
"they are killers"
] | D | carnivores are predators |
OpenBookQA | OpenBookQA-258 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
A hawk would prefer this for lunch | [
"Popcorn",
"Grass",
"Apple",
"A bison"
] | D | carnivores only eat animals |
OpenBookQA | OpenBookQA-259 | human-biology, breathing
Our lungs work off of pressure. Specifically our lungs inflate by using "negative pressure" (a word I've always hated). The pressure is not actually negative it is simply lower than the surroundings. Since there is less air in your lungs the air from the atmosphere rushes in because the pressure is higher outside your lungs. This is Boyle's Law (not the pressure outside being higher, but what happens when your lungs expand). Where an increase in Volume means a decrease in Pressure (if all else remains unchanged). In fact plants pull water up using negative pressure.
However to push out the air from our lungs we supply pressure using our muscles that overcomes the outside pressure and forces the air out.
The reason you feel your breathing change is because when that train passes by you correctly observed the strong gust of wind. This gust of wind has some force behind it that normally is not in the air you are breathing from the atmosphere. It has more force which increases the air's velocity. This actually decreases the pressure, but there's no need to get into that here (Bernoulli's).
The reason it feels like your body is "fighting to breath" is because the air is traveling in a direction with some force that you need to overcome by opening up your lungs just enough to "suck" the air in with negative pressure. This is more than the pressure you usually need to produce in order to breath in air that is "still".
What is funny to think about is we don't really have a muscle that "pulls" air in, even though it feels like you are actively doing that. The air actually rushes in on its own. All you do is expand your rib cage, which your lungs are attached to (look up on how, it's actually pretty cool), thereby making inhalation occur.
Now an interesting question for you to ask yourself is why is cold air harder to breathe?
The following is multiple choice question (with options) to answer.
Why is it dangerous for an animal to be kept boxed up in an area without air circulation? | [
"it will be confused",
"it might get too viscious",
"it will be scared",
"it might get overheated"
] | D | if an organism becomes too hot then that organism may die |
OpenBookQA | OpenBookQA-260 | 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.
Animals may relocate to a new environment if their old environment | [
"experienced a large hurricane",
"experienced a serious thunderstorm",
"had a few arid days",
"had little rainfall for a week"
] | A | natural disasters can cause animals to leave an environment |
OpenBookQA | OpenBookQA-261 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
many vehicles emitting pollution into the air may occur when | [
"horses pull carriage over snow",
"child is propelling scooter",
"trolley collects current from overhead wire",
"EMT transports panting patient"
] | D | many vehicles emit pollution into the air |
OpenBookQA | OpenBookQA-262 | electromagnetism, electricity, insulators
Title: How can a glass rod become charged if it is an insulator? I was reading some of the other questions, and I found this one about a glass rod and how it gains a net charge when rubbed with a silk scarf. I learned from working in a shop one summer that most solids are insulators, because their electrons are tightly bound, so it is hard to knock them off. Why would such a simple motion (like a moving scarf) knock electrons from an insulator (I looked it up and glass is an insulator)? Conductivity is not just about how tightly bound electrons are, but equally about how easy it is for them to travel.
Example: a bunch of islands in a shark-infested sea. You cannot swim from one island to the next although it is close. At low tide you can walk across no problem. The first example is an insulator, the second is a conductor.
Rubbing (google triboelectricity) causes unlike atoms to stick and unstick frequently. Atoms "fight" over electrons, and the stronger one gets to take the electron home. It is like air lifting them from the island - shark infested waters or not.
There are lists of materials (the triboelectric series) that tell you which material will give up its electrons when in contact with another material. Glass is high on the list - it loses electrons easily. The can't move sideway, but they can be picked off the surface.
The following is multiple choice question (with options) to answer.
What material is an example of an electrical insulator? | [
"Metal",
"Cement",
"Stone",
"Brick"
] | D | brick is an electrical insulator |
OpenBookQA | OpenBookQA-263 | atmosphere, moon, sun
Title: Why were both the sun and the moon red today? Today was a normal day, except the sun and moon colors were strange. After 5pm, the sky was covered with cirrostratus-like translucent clouds and the sky was a blend of blue and grey.
Everything would be fine, except that the sun was orange between 4-5pm. Then by around 5-6pm, the sun was completely red like blood even though it was still high up, and it was 1+ more hour to sunset.
Then, I didn't look at the sky until 8pm when it was already dark. When I went out, the moon was red just like the sun couple hours before.
The whole thing I saw from around south side od Chicago on US Labor Day (4 Sep, 2017). I didn't take pictures of the sun unfortunately because I disregarded its color, but I took pictures of the moon.
Here's how the moon looked through my phone camera, through binoculars:
Here is a similar picture but edited so that the moon looks exactly like I saw it with naked eye:
What can thia be caused by? (As of writing this at 10:06pm the moon is still red, and it is 6 hours since both the sun and the moon were red/orange)
EDIT: I also didn't see anything about this phenomenon in the media which is strange, and once again, this was seen from Chicago. Smoke. There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering. The smoke particles effectively cause the light to reflect in different directions, so you see more colors.
See below for the HMS Smoke Polygons for the day, which clearly shows smoke over your region from the intense smoke/wildfire activity in the Pacific Northwest. You can also see the NASA Worldview composite of VIIRS visible imagery for the day, with fire locations in red.
The following is multiple choice question (with options) to answer.
The sun was straight above us when we | [
"woke up",
"went to work",
"took a break",
"went home"
] | C | the sun is located directly overhead at noon |
OpenBookQA | OpenBookQA-264 | electricity, conductors, lightning
Title: Will putting a rubber cap on a steel bar prevent it from getting struck by lightning? Let's say there's a stainless steel bar pointing to the sky from the ground.
Like this there's a possibility it gets struck by lightning.
Now would putting a rubber cap on top of the bar change this or would the electricity travel around that cap and still hit the bar?
If not, would the steel bar be fully protected against lightning strikes like this? The electric field in the atmosphere will induce charges on the bar or the rubber cap. The surface density of the induced charges depends on, amongst other things, the curvature of the rod/rubber surface. Edges and points have a higher surface charge density than flat surfaces. The greater the surface charge density the greater is the likelihood of a lightning strike. The chances are that the rubber cap will have edges which are less sharp and so the probability of a lightning strike is reduced but I doubt that it will be by very much because the lightning can bypass the rubber and just head for the metal.
Rubber is also an insulator but if it is wet then the layer of surface moisture will act as a conductor. Even if there was no water present and the rubber was dry given the size of the electric field which will be present the rubber will probably still conduct.
The following is multiple choice question (with options) to answer.
Rubber can protect from | [
"cold",
"burns",
"electricity",
"fire"
] | C | rubber is an thermal insulator |
OpenBookQA | OpenBookQA-265 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
A pollutions standard is something which | [
"will hopefully limit the amount of damage done to the environment by large producers",
"a standard that gets applied to every person",
"a way to get factories to make more product",
"the best way to reduce poisoning the trees in Michigan"
] | A | a pollutions standard is a kind of standard for reducing pollutants emitted by factories |
OpenBookQA | OpenBookQA-266 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
Electricity causes less damage to the Earth's atmosphere than | [
"Gasoline",
"Potatoes",
"The sun",
"Water"
] | A | electricity causes less pollution than gasoline |
OpenBookQA | OpenBookQA-267 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
If a river is rushing southwest on a sunny day, then it is safe to assume that | [
"southwest is a good place to be",
"the land gently inclines in that direction",
"the world is mostly land",
"the land is supple"
] | B | the slope of the land causes a river to flow in a particular direction |
OpenBookQA | OpenBookQA-268 | stereochemistry, carbohydrates
If you want to make models, at your next wine and cheese party get some toothpicks, and two pieces each of four different kinds of cheese. Put four of the cheese chunks on the end of the toothpicks, and then stick the tooth picks in a sausage or something. Then make an exact copy. After that is done, exchange two of the cheese chunks on one model and investigate what you have. There should be no way you can twist or turn or rotate one model to have its kinds of cheeses in the same orientation as the other. Once you have done this, the following picture will make much more sense:
The following is multiple choice question (with options) to answer.
Using a metal kitchen tool on a cheese can create | [
"milk",
"blue cheese",
"melted cheese",
"small pieces"
] | D | scraping an object may cause small particles to break off of that object |
OpenBookQA | OpenBookQA-269 | optics, geometric-optics
EDIT:::Clarifications
This question is the result of a debate with my friend, who says the room would be dark and me who says otherwise.
Now being said that let's move to specifics...let's assume that the room is a cuboid and the light source is say a light bulb i.e. an isotropic source like a typical room at ceiling. and the observer with infinitesimally small view port looking from one of the wall presumably neither the ceiling nor floor.
I hope this suffices. You use the verb "to be," which is rather deceptive in this situation (and in questions of optics generally). The room itself would not "be dark" or "be light," it would be a collection of various particles, some of which would be photons in the visible spectrum. It really only makes sense to ask how the room would appear to an observer looking through the viewport.
Even if you had completely reflective surfaces, the way the room appeared would depend significantly on the orentientation of the mirrors, the orientation of the viewing hole, the focus of the light, and perhaps most importantly, the refractive and diffusive properties of the mirrors. Ultimately, the appearance of the room would be a result of the light that falls upon the viewport. While there are an infinite variety of possible arrangements, the two extremes roughly align with the two possibilities you suggest.
For the room to look completely dark, no light paths fall on the viewport. A laser perpendicular to two parallel mirrors with the line of sight also parallel to the mirrors would produce this effect.
For the room to look completely bright, all (or however much you require to meet that definition) light paths fall on the viewport. A room in the shape of a truncated paraboloid with the viewport at the focal point would produce this effect.
Edit
I decided to move these up to my answer to avoid a prolonged comment conversation.
The following is multiple choice question (with options) to answer.
Someone in a room without any lights on, but that has mirrors in it, can still have light in that room if | [
"lights are turned on in another house",
"a joined room is dark",
"the room is completely dark",
"a joined room is lit"
] | D | a mirror is used for reflecting light |
OpenBookQA | OpenBookQA-270 | specific-reference, solid-state-physics, semiconductor-physics
As far as technological applications go, improving the mobility gives circuit designers the ability to construct circuits with higher performance. In the following paragraphs I will explain what this higher performance exactly means. Before I explain these applications is important to emphasize the difference between the physics and engineering parts of it. There are a lot of different factors that need to be considered while designing a "good" circuit. I will admit that simply improving mobility will not solve all the performance problems. As a matter of fact, certain categories of circuit design have evolved to the point where the performance of the circuit depends mainly on the design and very little on the material parameters. But there are some applications where the physics starts becoming important.
Here is an example where you care about the gain of the transistor. If you are trying to use it as an amplifier you are going to use it in an analog circuit. Higher mobility means higher intrinsic gain of the transistor. The overall gain depends on how these transistors are interconnected. People have come up with many tricks and circuit design strategies to get way more overall gain compared to its intrinsic gain. However, if the intrinsic gain were increased you can get even higher overall gain for the same circuit design.
The following is multiple choice question (with options) to answer.
The increase in transport ability may increase the available types of | [
"houses",
"education",
"internet",
"grains"
] | D | as ability to transport food increases around the world , the available types of food in distant locations will increase |
OpenBookQA | OpenBookQA-271 | evolution, botany, proteins
tl;dr: the egg contains more proteins than the seed because the chicken that made the egg ate a whole lot of seeds, and all the protein in those seeds ended up concentrated in that one egg.
EDIT: running into this much later I realized I missed a pretty vital half of the question, because there is a difference between fruits and seeds. The difference is the following: nitrogen is precious for plants so they'll try and use it for very important things. Seeds are very important to the plant, so while a seed has less protein than an egg it will still have lots of protein by plant standards. Fruits now, that's another story. Like the sugary nectar, fruits are a bribe for animals, a bit of food offered to them so that they'll spread the plant's seeds. And like with the sugary nectar, the plant has every incentive to pack that bribe full of cheap carbohydrates and as few precious proteins as it can manage.
The following is multiple choice question (with options) to answer.
seeds are often found inside a | [
"banana",
"cherry",
"olive",
"strawberry"
] | B | a berry contains seeds |
OpenBookQA | OpenBookQA-272 | (foxes) at the time ts(j). (3)yxy to illustrate the Maple, Mathematica, and MATLAB techniques needed for these investigations. Usage of odeset and table indicating which options work with each ODE solver. Midterm 2 (lectures of October 18–November 8) Nov 21. 26th Sep, 2017. We consider a complex population dynamics mathematical model involving foxes and rabbits as predators and prey. Ask Question Asked 5 years, 4 months ago. Participants performed this task standing on separate sides of a board and controlling a marker representing them. George Maria Selvam2 and V. How can I draw a bifurcation plot in MATLAB? Can someone help. We model the hunt as a game of three explicit stages: the stalk, the attack, and the subdual. x=[628 703 778]; y=[1771 1403 1035]; There are numbers of rabbits and foxes in following years. where x(t) and y(t) are the prey and predator population sizes at time t, and p,q, r, and s are biologically determined parameters. With MATLAB's built-in functions and easy syntax, integrating computation into coursework is not only feasible but also straightforward. [ts,ys] gives a table with t in column 1, y1 (rabbits) in column 2, y2 (foxes) in column 3. This work is arranged as follows: Sections “PREDATOR–PREY MATHEMATICAL MODEL” and “WEAK ALLE EFFECT CASE STUDY ANALYSIS” recall the nonlinear model as well as its basic dynamics. Distinct real eigenvalues. Tutorial: Use MATLAB to illustrate a predator-prey relationship using a Discrete Dynamical Systems Model. Abstract This lecture discusses how to solve Predator Prey models using MatLab. The prey-predator-predator equations get cool looking chaotic dynamics not seen in 1 or 2 dimen-sions. rar > FD2D 2D Predator Prey Simulation. A DC Motor subsystem which is model using Simulink blocks and a 3D Model which is imported from Solidworks using the SimMechanics Link. Our model used a spectrum of correlated random walk rules of movement, from strictly nondirectional to almost directional movement, while abstracting the cost associated with searching. B=Rate at which predators destroy prey. Bio-mathematical Prey-Predator Model with Marine Protect Area(MPA) and Harvesting
The following is multiple choice question (with options) to answer.
If two hawks find a dead fox, they will | [
"eat",
"battle",
"starve",
"fly"
] | B | if two animals have the same food source then those two animals compete for food |
OpenBookQA | OpenBookQA-273 | earth-rotation, seasons, time
Title: Are the length of seasons the same globally? Is the length of time, say months, for each season the same all over the world or can it vary? As has been noted in a comment, it depends on how you define seasons (see https://earthscience.stackexchange.com/a/2603/111).
If seasons are defined in astronomical terms, then they have the same length everywhere on the planet. This is simply down to geometry.
However, the effects of astronomical seasons vary geographically in a number of ways. The magnitude of seasonal changes, for example changes in day/night lengths, is more pronounced in higher latitudes, so the effect of (for example) winter might be noticeable for a shorter time period in the tropics than the arctic, and hence some people might reasonably consider winter to be shorter there. There are other, less systematic variations that depend on local climate and weather. In weather terms, not everywhere in the world has the same 4-season cycle that temperate zones tend to experience - so when defining seasons in terms of observable effects one often has, for example, a wet season and a dry season rather than spring /summer /etc.
The following is multiple choice question (with options) to answer.
Seasons of the year highly impact what? | [
"Moods",
"Environment",
"Behavior",
"Consumption"
] | B | seasons cause change to the environment |
OpenBookQA | OpenBookQA-274 | cosmology, nuclear-physics, space-expansion, universe, binding-energy
Title: What happens when the universe runs out of fuel? After some X billion years, one would think the stars in the entire universe will run out of hydrogen. What would happen next? Is there any way to get hydrogen out of heavy metals (extreme fission)? Just curious. Then star formation ceases and the universe goes dark. At this stage of the universe's evolution, there'll still be plenty of hydrogen, they just don't form stars.
In theory you can create hydrogen out of heavy metals, but it's a process that requires energy. If you have the energy banked somewhere (and you'll need a LOT of energy to make enough hydrogen for a new star) then it's possible.
The following is multiple choice question (with options) to answer.
There are fuels that we are soon to run out of, and there are options that are like the sun, in that | [
"they are endlessly available",
"inexpensive to store at home",
"free for everyone's use",
"available to the public"
] | A | solar energy is a renewable resource |
OpenBookQA | OpenBookQA-275 | light, history, speed
% WaaeaacaaIXaGaey4kaSYaaSaaaeaacqqHuoarcaWGwbaabaGaam4q
% aaaaaiaawIcacaGLPaaacaWGMbWaaSbaaSqaaiaad+gaaeqaaaaa!3BBB!
$$
I hashed through the numbers myself and I got an answer of about 10 minutes more or less from 42 hours depending on which way the earth is heading with reference to Jupiter. Ole Rømer did not measure a change in the frequency of light. He measured an apparent change in the orbital period of Io, one of Jupiter's moons.
The orbit of Io can be measured very accurately by observing when it enters or leaves the shadow of Jupiter. When the Earth is moving away from Jupiter, Rømer noted that the orbit of Io appeared to be very slightly longer than when the Earth was moving parallel to Jupiter.
Suppose the orbital period of Io is $p$ seconds. If you are not moving and you observe an eclipse at time $t$, the next eclipse will be at time $t+p$. However, if you are moving away from Io, the next eclipse will be seen at $t+p+x$, where $x$ is the time that light takes to travel from your position at time $t$ to your position $p$ seconds later.
The delay over a single orbit was too small for him to measure (about 30 seconds). But the delay was cumulative, and over about 30 orbits of Io, the orbit was delayed by about a quarter of an hour. He noted:
The following is multiple choice question (with options) to answer.
while passing Jupiter the | [
"better the view",
"stronger the gravity",
"moon orbits you",
"gravitational force weakens"
] | B | as distance from an object decreases , the the pull of gravity on that object increases |
OpenBookQA | OpenBookQA-276 | java, object-oriented, state-machine
// Draw the ocean
for (int x = 0; x < width + 2; x++) {
System.out.print("-");
}
System.out.println();
for (int row = 0; row < height; row++) {
System.out.print("|");
for (int col = 0; col < width; col++) {
Critter creature = sea.cellContents(row, col);
System.out.print(creature.getClass().getName().substring(9, 10));
}
System.out.println("|");
}
for (int x = 0; x < width + 2; x++) {
System.out.print("-");
}
System.out.println();
}
}
/**
* main() reads the parameters and performs the simulation and animation.
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException {
Ocean sea;
/**
* Read the input parameters.
*/
if (args.length > 0) {
try {
width = Integer.parseInt(args[0]);
} catch (NumberFormatException e) {
System.out
.println("First argument to SimText is not an number");
}
}
if (args.length > 1) {
try {
height = Integer.parseInt(args[1]);
} catch (NumberFormatException e) {
System.out
.println("Second argument to SimText is not an number");
}
}
if (args.length > 2) {
try {
starveTime = Integer.parseInt(args[2]);
} catch (NumberFormatException e) {
System.out
.println("Third argument to SimText is not an number");
}
}
Shark.starveTime = starveTime;
/**
* Create the initial ocean.
*/
sea = new Ocean(width, height);
The following is multiple choice question (with options) to answer.
The sea is | [
"A mega Museum",
"A solid",
"Jello",
"Candy"
] | A | oceans cover 70% of the surface of the earth |
OpenBookQA | OpenBookQA-277 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
A beak is used for catching prey by some birds, like how they are used by | [
"chickadees",
"glass flamingos",
"chicks",
"plastic parrots"
] | A | a beak is used for catching prey by some birds |
OpenBookQA | OpenBookQA-278 | botany, plant-physiology, reproduction, plant-anatomy, life-history
In dimorphic cleistogamy CL and CH flower differ in the time or place
of production, with CL flowers produced in conditions (underground,
low light levels, early in the season) that are potentially
unfavorable for outcrossing.
In induced cleistogamy potentially CH flowers that experience conditions such as drought or low temperatures fail to open and self-pollinate, becoming, in effect, CL flowers.
You should check out the Culley and Klooster (available online if you make a jstor login) – they discuss complete cleistogamy which addresses your last question. They report several completely CL species in their Table 1, and give references.
More generally, many different plant groups maintain balances of self-pollination and outcrossing (i.e. "real sex"), through an even more diverse set of mechanisms.
Even more generally, many plants and some animals maintain balances of sexual reproduction and clonal reproduction, through an even more diverse set of mechanisms. For instance, vegetative reproduction (e.g., strawberry runners) is very common in many plant groups; facultative and obligate parthenogenesis in animals also occurs.
Culley, Theresa M. and Matthew R. Klooster (2007). The Cleistogamous Breeding System: A Review of Its Frequency, Evolution, and Ecology in Angiosperms. Botanical Review. Vol. 73, No. 1, pp. 1-30
The following is multiple choice question (with options) to answer.
Flowers will reproduce more if | [
"dragonflies reproduce more often",
"pollinators visit them sparingly",
"they are planted in premium fertilizer",
"more bees make a pit stop at them"
] | D | as the number of pollinators attracted to a flower increases , the ability of that flower to reproduce will increase |
OpenBookQA | OpenBookQA-279 | distances, coordinate
Title: How to calculate distance from object to point on celestial sphere I'd like to calculate the distance (in arcsec) from the object nearest to ra='08h55m10s' dec='-7d14m42s' to that point on the celestial sphere.
I am actually having trouble identifying the object. I have python code to run a cone search:
from astropy.coordinates import SkyCoord
from astroquery.irsa import Irsa
import astropy.units as u
loc = SkyCoord('08h55m10s',' -7d14m42s','icrs')
table = Irsa.query_region(coordinates=loc,catalog="wise_allsky_4band_p3as_psd", radius= 1 * u.arcminute)
print(table)
The following is multiple choice question (with options) to answer.
Which celestial object is the shortest distance from earth? | [
"Mars",
"Moon",
"Milky Way",
"Venus"
] | B | the moon is the celestial object that is closest to the Earth |
OpenBookQA | OpenBookQA-280 | 1. $$(A \lor B) \& (Y \Rightarrow Z), \ \therefore Y \Rightarrow Z$$
2. $$(A \lor B) \& (Y \Rightarrow Z), \ \therefore (A \lor B) \& (Y \Rightarrow Z)$$
3. $$A \lor B, \ \therefore (A \lor B) \lor (Y \Rightarrow Z)$$
4. $$(A \lor B), (Y \Rightarrow Z), \ \therefore (A \lor B) \& (Y \Rightarrow Z)$$
## Exercise $$1.9.8$$.
Each of the following is the English-language version of a valid theorem that is obtained from one of the basic theorems of Table 1.9.1, by substituting some expressions into the variables. Identify the theorem it is obtained from.
1. Susie will stop at either the grocery store or the drug store. If she stops at the grocery store, she will buy milk. If she stops at the drug store, she will buy milk. Therefore, I am sure that Susie will buy milk.
2. My opponent in this election is a liar! My opponent in this election is a cheat! Therefore, I say to you that my opponent is a liar and a cheat!
3. John went to the store. Therefore, as I already told you, John went to the store.
4. If I had $50, I would be able to buy a new coat. Hey, look! I found a$50 bill on the sidewalk! So I will be able to buy a new coat.
The following is multiple choice question (with options) to answer.
Which would be a logical hypothesis after viewing a white substance on the floor, with a yellow carton on the counter? | [
"milk was spilled",
"white juice spilled",
"bleach was spilled",
"was an illusion"
] | A | hypothesis means scientific guess about the cause and effect of an event |
OpenBookQA | OpenBookQA-281 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
With the apple tree chopped down, there was now no place for | [
"apples",
"apple pies",
"falling leaves",
"bird's nests"
] | D | cutting down trees has a negative impact on an organisms living in an ecosystem |
OpenBookQA | OpenBookQA-282 | biology, dimensional-analysis, scaling
Title: Why are smaller animals stronger than larger ones, when considered relative to their body weight? I am interested in why many small animals such as ants can lift many times their own weight, yet we don't see any large animals capable of such a feat.
It has been suggested to me that this is due to physics, but I am not even sure what to search for. Could someone explain why indeed it is easy for smaller objects/lifeforms to support several times their own weight, but this is harder as objects/animals become larger? Zasso pointed it already out:
Scaling up a ant to human size means volume (weight) increasing by length proportional $l^{3}$, but the force of muscles is determined by cross section (not muscle weight), so muscle force goes proportioal to $l^{2}$.
Smaller factors are likely:
stiffness (or strentgh of the skeleton)
balance point (center of mass)
leverage (human skeleton is "sub-optimal" for this, we are afaik best optimized by evolution for long runs, more than any other animal)
i did some quick further search on "robot insects" on this interesting topic. This article is quite worth reading and relating biological to technological limits as well as current state of the art in nanobionics:
Interestingly, the force generated
from a wide variety of actuator
materials and devices has been found
to be surprisingly invariant when
compared with the actuator mass. A few
years back, a comparison of the
force-to-weight ratio of various
organisms and machines found a
striking similarity, with the force
scaling linearly with mass over 20
orders of magnitude – from individual
protein molecules to rocket engines
("Molecules, muscles, and machines:
Universal performance characteristics
of motors"). Remarkably, this finding
indicates that most of the motors used
by humans and animals for
transportation have a common upper
limit of mass-specific net force
output that is independent of
materials and mechanisms. Therefore
any actuating device produces the same
force per mass regardless of the
material from which it is constructed
and the mechanism by which it
operates. This study also makes clear
that biological systems dominate at
the small mass, small force, range. In
contrast, human-made machines dominate
at the large mass range.
The following is multiple choice question (with options) to answer.
What makes a body stronger? | [
"parking far away",
"travelling by air",
"reading technical books",
"having multiple children"
] | A | exercise has a positive impact on a body 's strength |
OpenBookQA | OpenBookQA-283 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
Recycling old cars has a positive impact on | [
"the weather",
"conservation of metal",
"human life span.",
"the economy"
] | B | recycling nonrenewable resources has a positive impact on the conservation of those resources |
OpenBookQA | OpenBookQA-284 | botany, ecology, energy
Title: Why do plants create enough energy for the entire ecosystem? In my environmental class, we were recently learning about the $10\%$ law that basically says only $10\%$ of the energy goes from one trophic level to the next.
This got me thinking about why energy flows from one level to the next. Specifically, why do plants create enough energy for the entire ecosystem? Wouldn't they do fine without us, and wouldn't that save them the work of creating all that excess energy? Plants collect energy for themselves via photosynthesis, not for others.
It is used for it's own growth and survival.
It's energy is then redistributed to other organisms when either the plant dies and decomposes or when it is consumed. Many organism cannot collect their energy like plants do, and thus must feed on organisms (like plants) that are able to collect and store energy. This is in many cases detrimental to the plant (it should be intuitive why being eaten might be bad), and many, many plants do have traits to discourage other organisms from eating them (plants with toxins, thorns, etc.).
The following is multiple choice question (with options) to answer.
Organisms require energy in order to do what? | [
"rest soundly",
"absorb light",
"take in nutrients",
"mature and develop"
] | D | an organism requires energy for growth |
OpenBookQA | OpenBookQA-285 | 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.
Where would the amount of water decrease most? | [
"under clear skies",
"in the clouds",
"during a storm",
"indoors"
] | A | evaporation causes amount of water to decrease |
OpenBookQA | OpenBookQA-286 | species-identification, ornithology
Why would a mother do that to her young? Does she hates the little one? Not at all. It’s just that those little birds were made to fly, and they don’t know it, so she is going to push them out of the nest. She never lets them hit bottom, but she does let them fall, because they have to learn something they don’t know.
The next time the mother bird comes back she decides to clean house, and so she stands on the edge of the nest. The first things to go are the feathers inside; she drops them over the edge. Then the leaves go over the edge—heave ho! While this is going on, she’s not very talkative, either. ("Mom, what are you doing?") She pays no attention. Since she built the house, she knows how to take it apart.
Next she decides to take the sticks out of the middle of the nest, and with her great strong beak and feet, she’s able to break them off and stand them straight up. ("Mom, it’s not comfortable in here anymore.") Then she takes certain key sticks out of the nest and throws them over the edge. ("What are you doing, Mom? You are wrecking my room.")
She seemingly pays no attention to the concerns of her young as she prepares to pull the nest apart, for she is determined that those little ones will fly, and she knows something they don’t. She knows they will never fly as long as they remain in the nest.
The following is multiple choice question (with options) to answer.
If your pet bird is having trouble flying | [
"lock them in their cage more",
"give up and get a new bird",
"try putting them on a diet",
"take away all their perches"
] | C | as the weight of an animal decreases , that animal will fly more easily |
OpenBookQA | OpenBookQA-287 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
Seasons are caused by | [
"weather patterns",
"earth's movement pattern",
"weather changes",
"weather cycles"
] | B | the Earth being tilted on its axis causes seasons |
OpenBookQA | OpenBookQA-288 | • 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.
If a fox shuffles off the mortal coil, then that fox | [
"is a burden",
"ceases to exist",
"is missing",
"is pregnant"
] | B | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-289 | zoology, ethology, learning
Title: How do beavers learn how to build dams? I was wondering whether all beavers, from all around the world, know how to build dams and lodges? Do they need to learn it from their parents? If you release a group of beavers in the wild that haven't been in contact with their parents, would they start to build stuff? or just hopelessly die/starve to death? Question summary: is dam building learned or instinctive in beavers?
A blog post from 2011 references an article in the Juneau Empire titled Running water is sound of spring for beavers. This article is no longer hosted on the Juneau Empire website, but archived versions are available.
Here's an excerpt (emphasis mine) --
Swedish biologist Lars Wilsson spent years studying captive and wild beavers, and he gained remarkable insights into their behavior. He raised beavers in an outdoor enclosure and in a large indoor terrarium ...
Wilsson initially captured four adult beavers and later he raised a number of beavers from infancy, some in small colonies with their parents and some completely isolated from adult beavers. He isolated the young beavers to see what beavers learn from their parents and what behaviors are instinctive.
He found that young beavers - who had never even seen a beaver dam - were able to build almost-perfect dams at the first opportunity.
The foundation of sticks and logs anchored to the stream bottom, the interwoven lattice of trimmed branches, the mud chinking, every aspect of dam building was hard-wired. Beavers do get more skilled at dam building as they gain experience, but the building behavior is instinctive.
Wilsson learned that the sound of running water is the cue for dam building and dam repair. In one experiment, he played a recording of running water, and the young beavers built a dam in a tank of still water in the terrarium. In another peculiar experiment, his captive beavers built a "dam" on a concrete floor against a loudspeaker that played the sound of running water.
The following is multiple choice question (with options) to answer.
A beaver is building a home in a river, and that eventually blocks up the river, giving the beaver a nice home. A side effect of the beaver's new home is | [
"a pool",
"freshwater body",
"a mountain",
"an ocean"
] | B | damming a river can cause a lake to form |
OpenBookQA | OpenBookQA-290 | ros, arduino, usb, hardware
Originally posted by tfoote with karma: 58457 on 2011-02-16
This answer was ACCEPTED on the original site
Post score: 9
Original comments
Comment by mjcarroll on 2011-02-16:
This is exactly what we do. We choose some informative names as well, like /dev/lrf, /dev/motor_controller, /dev/power_board. It makes things easy to find for both ROS parameters and interfacing with a terminal (like screen) if your device's protocol is "human readable".
Comment by tfoote on 2011-02-16:
copied to work around http://askbot.org/en/question/293/how-can-an-admin-answer-own-question-and-accept-it
The following is multiple choice question (with options) to answer.
A remote device may be powered by | [
"a burning flame",
"a gusting breeze",
"a running sheep",
"a small explosion"
] | B | wind is used for producing electricity |
OpenBookQA | OpenBookQA-291 | zoology, ethology, behaviour, psychology, death
Strange thought
Organisms that have not evolved the ability to make "conscious choices" cannot decide to end their life. You will be hard-pressed to find any scientific data on this question. Psychology in humans is already a difficult study, at times failing to demonstrate results with real scientific rigor. When studying animal psychology, you face another substantial barrier - language. Although some primates have been taught to communicate with sign language, the best of them are still far from the level of proficiency of a human. We can measure brain activity and observe behavior, which can lead us to strong suspicions about what is going on in an animal's mind, but very little can actually be proven.
Mostly, all we can do is speculate about such questions. You will find some veterinarians out there who treat pets for mental conditions, but you will find at least as many people calling them quacks as those who believe in the validity of their work. And certainly, they can't prove to you that a treatment has helped an animal. It's subjective.
If we see an animal do something which in a human might reliably be interpreted as a sign of depression, it's possible that this interpretation is appropriate for the animal as well. It's also possible that there is some totally foreign unrelated explanation. The problem we find when trying to scientifically discuss matters which cannot be proven scientifically is that scientists must be careful to state what they know and nothing more. So they might say "We cannot prove that the porpoise is depressed", or "Science cannot prove the existence of a God." This is often misinterpreted as evidence against the finding - that the porpoise is not depressed; that there is no God. This is a fallacy. Rather, we should recognize that we have different ways of exploring questions like these.
The following is multiple choice question (with options) to answer.
What shows that animals learn behaviors by watching their parents? | [
"kittens groom their faces because their mother licked their faces",
"dogs bark because their parents barked at them",
"babies cry because overtired parents cry",
"kittens climb trees because they watch squirrels do it"
] | A | animals learn some behaviors from watching their parents |
OpenBookQA | OpenBookQA-292 | visible-light, electromagnetic-radiation
Title: Why is visible light right at the border of ionizing radiation? I'm a physics layman, but was reading about ionizing vs. non-ionizing radiation, and it seems unlikely to be a coincidence that visible light (and some UV) spans the shortest wavelengths you can have before getting into ionizing territory. This is perhaps partially a biology question, but is there a reason that things worked out that way, or is it just happenstance stemming from Earth's atmospheric composition, the type of star we have, and other (somewhat) chance factors like that? In the course of evolutionary history presumably the earliest forms of light detection were cells capable of sensing the difference between day and night.
For organisms a necessary property of a vision system is that the chemistry that is involved must be reversible. The reason for that: a form of photosensitivity where the photosensitive molecules are single-use will cost too much energy, such a form is not viable.
In eyes the photosensitive cells contain a class of proteins named "opsins". The members of this class of proteins are light-sensitive in a specific way. There is a range of energy of incoming light where upon absorbing that light the opsin goes from one level of energy to another level, without the change being irriversible. Another protein that is hugging the opsin shepherds the relaxation back along a specific route. One step in this route contributes to triggering a neuron to signal that light has been detected.
Infrared light does not have enough energy to cause the needed energy step. In the course of evolution the first opsin has diverged into a class of opsins, so that the the opsins together cover a range: that constitutes the range of visible light.
Light with enough energy to ionize is much harder to utilize. It's too much energy, in general the molecule absorbing it will be damaged.
(In addition, if I recall correctly, the lens of the eye is not translucent to UV-light. It remarkable in the first place that the cornea and the lens are as widely translucent as they are. For a material to be translucent the light passing through it must have no opportunity to transfer energy to any of the molecules of that material.)
The following is multiple choice question (with options) to answer.
ultraviolet light is found in light from where | [
"the flaming ball of gas we orbit",
"giant planets in the neighborhood",
"light sources that we create",
"balls of fire lit with gas"
] | A | sunlight contains ultraviolet light |
OpenBookQA | OpenBookQA-293 | space, vacuum
Title: Effects on a tree exposed to the vacuum of Space My wife's kindergarten class asked, "What would happen to a tree planted on the moon?" Aside from the obvious that it would die from lack of water/air, what physical effects would happen to a tree exposed to the vacuum of Space? This is a question for a biologist.
To start with, I guess it would freeze dry, by the water evaporating due to the lack of atmosphere, as Ted observed. If you have forgotten an unwrapped piece of food in the freezer you would know what it means.
Then also the rest of the molecules which are made up mostly of Carbon and Hydrogen would slowly sublimate. If in the sun, much faster.
Now if one assumes a bubble of atmosphere and appropriate water and fertilizer, and the question concerns if the moon soil could support a plant, the answer is , yes, if earth soil microorganisms are introduced into the moon soil where the plant is planted. The technique exists used for improving poor soils.
(I recently learned about it from discussions about planting a sour cherry tree in poor soil.)
The following is multiple choice question (with options) to answer.
As a result of decreased water, what will happen to tree rings? | [
"Lose shape",
"Become narrow",
"Become wider",
"Disappear Completely"
] | B | as the amount of available water decreases , tree-growth rings will become narrower |
OpenBookQA | OpenBookQA-294 | [13]:
nutrients = pd.DataFrame(
index=[
"Vitamin A",
"Vitamin B1",
"Vitamin C",
"Calcium",
"Iron",
"Phosphorus",
"Potassium",
"Total fat",
"Carbohydrates",
"Proteins",
]
)
nutrients["DRI"] = [800, 1.1, 80, 800, 14, 700, 2000, 70, 260, 50]
nutrients["Chicken Breast"] = [0, 0.1, 0, 4, 0.40, 210, 370, 0.8, 0, 23.3]
nutrients["Milk"] = [37, 0.04, 1, 119, 0.1, 93, 150, 3.6, 4.9, 3.3]
nutrients["Pasta"] = [0, 0, 0, 22, 1.4, 189, 192, 1.4, 79.1, 10.9]
nutrients["Beans"] = [3, 0.4, 3, 135, 8, 450, 1445, 2, 47.5, 23.6]
nutrients["Oranges"] = [71, 0.06, 50, 49, 0.2, 22, 200, 0.2, 7.8, 0.7]
nutrients
[13]:
DRI Chicken Breast Milk Pasta Beans Oranges
Vitamin A 800.0 0.0 37.00 0.0 3.0 71.00
Vitamin B1 1.1 0.1 0.04 0.0 0.4 0.06
Vitamin C 80.0 0.0 1.00 0.0 3.0 50.00
Calcium 800.0 4.0 119.00 22.0 135.0 49.00
Iron 14.0 0.4 0.10 1.4 8.0 0.20
Phosphorus 700.0 210.0 93.00 189.0 450.0 22.00
Potassium 2000.0 370.0 150.00 192.0 1445.0 200.00
Total fat 70.0 0.8 3.60 1.4 2.0 0.20
Carbohydrates 260.0 0.0 4.90 79.1 47.5 7.80
Proteins 50.0 23.3 3.30 10.9 23.6 0.70
The following is multiple choice question (with options) to answer.
Vegetables provide a lot of nutrients for | [
"cats",
"dogs",
"humans",
"snakes"
] | C | an animal needs to eat food for nutrients |
OpenBookQA | OpenBookQA-295 | botany, species-identification
Title: Which plant is this? I'm curious what plant this is! I found it at 37°52'23.2"N 122°16'55.3"W (north of Oakland, California, USA). That's East Indian Fennel. It's a member of the celery family. Every part is edible, including the root and the seeds. It's packed with vitamins, calcium and is used to stop restless leg syndrome, among other ailments. The feathers (leafs) can be used to wrap meat and fish before baking or eaten fresh on a green salad. Once par boiled they lose their licorice taste and can be eaten like steamed spinach. The Italians brought it over in the early 1800s and it flourished. It grows along the freeways of California and other states. I pick large batches of it for my juice extractor and other things. Look up the many medicinal uses of fennel. The flowers look similar to dill.
The following is multiple choice question (with options) to answer.
A prickly pear absorbs nutrients from | [
"below it",
"far from it",
"beside it",
"above it"
] | A | plants absorb nutrients from soil into themselves through their roots |
OpenBookQA | OpenBookQA-296 | electricity, electric-circuits, electric-current
Now if you connect an electric heater and turn it on then current will flow into the heater and then out of the heater for each part of the ac cycle and current will flow through the ring main - you can think of it like a river with a large island in the middle and narrow channels each side of the island - water can flow around the island both ways and in the same direction on both sides of the island - how much flows on each side will depend on the length of the channels and other factors..... except becaue the current is ac in our model of the island in the river the water has to flow downstream - and then upstream... this could happen in tidal river where the direction of current can change due to the tide coming in or going out.
Now when we think about ac current it is aways going one way and then the other and if we took an average of the current we would always get zero, which is not very helpful. So to measure ac current we normally look at the `rms' value... the root mean square - we square the current so that both positive and negative currents give a positive value, take the average and then take the square root. So if an ac device needs 5 Amps of current then that probably refers to the rms value.
So when we talk about ac current it is always changing direction, but if we use rms values we can actually get a useful quatitative measure for the ammount of current going backwards and forwards in each cycle.
... sorry now rather long answer.. hope it is useful
The following is multiple choice question (with options) to answer.
If electrical current is running | [
"the wire may be hot to the touch",
"the wire may be cool to the touch",
"the wire is automatically grounded",
"the wire is automatically water safe"
] | A | electrical current running through a wire causes that wire to heat up |
OpenBookQA | OpenBookQA-297 | 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.
If a wolf is unable to catch prey reliably, the wolf will | [
"show ribs",
"hunt more",
"have pups",
"take naps"
] | A | as the amount of food an animal eats decreases , that organism will become thinner |
OpenBookQA | OpenBookQA-298 | meteorology, barometric-pressure, radiosounding
But you'll find that pressure at the ground is lower in most locations than is indicated on such a map. This is because, despite being called "surface maps", they're actually sea-level pressure maps. At any station situated above sea-level a weather balloon cannot acquire that sea-level pressure. So the pressure must be extrapolated downward using these same equations.
But that still doesn't answer why we'd opt for isohypses...
One benefit may be that height maps are similar to topographic maps.
But it well truly stem from early meteorological rules of thumb. One important forecasting tool before advanced weather models came from the thickness equation (an application of the hydrostatic approximation). It works out that the thickness between 500 mb and 1000 mb was a helpful indication of what kind of precipitation would fall. Values lower than 5400 m indicate that the air column is probably cold enough for snow.
It seems quite feasible that this was relationship was noticed even before the equations were understood. 1000 mb is very close to the surface pressure in many of the big cities during the early development of meteorology (such as New York City, Boston, London, and Paris). So all they'd need to notice is a connection of the 500 mb height and the precipitation type. This might be easier than spotting a pattern of ratios of 5400 m pressure values to surface pressure values around 0.5.
In the end, it probably goes back to how early upper-air observations were recorded. It may well have been some guy going up in the balloons until radio, so would they have recorded at equal heights or equal pressures? Or when radio and the early instrumentation were developed, what would draw them to choose set pressures or set heights? I don't know the history well enough to give a certain answer to that.
In the modern era, models quite often use pressure coordinates (or similar sigma coordinates). In addition, if you wished to calculate the quasigeostrophic omega equation or apply the quasigeostrophic height tendency equation, perhaps equal pressure maps might be slightly more useful. However, I tend to doubt either of these are nearly significant in the overall development of the practice.
The following is multiple choice question (with options) to answer.
what does a barometer do to air pressure | [
"state its tightness",
"store it",
"disperse it",
"condense it further"
] | A | a barometer is used to measure air pressure |
OpenBookQA | OpenBookQA-299 | development
Title: How detachment/separation works in biology? It might be a strange question, but I'm interested in the mechanics of separation/detachment during asexual reproduction, for example when an organism reproduces by budding (I don't mean cellular budding like baker's yeast). When the newly formed body is fully matured it detaches itself from the parent / original body.
It might not be caused by a specific tissue, as animals with not so differentiated bodies are (also) capable of such, but I could easily be wrong. Is this (the detachment) triggered by changes in the cell membrane? I can't really think of other explanations. Reproductive budding and what you call 'cellular budding' are really highly related processes. Budding as a form of reproduction essentially partitions protein aggregates and damaged cellular components into the host or mother and builds fresh or 'young' cells on the opposite side of a partition. To begin understanding this look at Saccharomyces cerevisiae (budding yeast) which forms protein rings (from the septin proteins) at the membrane, around the bud neck which separates the mother and daughter cells Hartwell 1971. This ring acts a partition that in part, withholds protein aggregates and certain proteins from diffusing from the mother to the daughter. This protein ring is an example of how cells limit diffusion of proteins and cellular components to the daughter cell. Another good example that comes to mind is Linder 2007, though it is done in E Coli, not budding yeast, where mother cells maintain protein aggregates and age, while the daughter cells are given fresh components and are therefore more fresh and 'young'.
Now like you mention, imagine this process in a multicellular organism to be fundamentally the same. At some point the multicellular organism will start an outgrowth of cells, while restricting what materials are given to the daughter cells to maintain their youth. And eventually a new organism will have been created. Some of the details will be different, but the fundamental process is is quite similar. In that you start with an old cell that creates a new cell from scratch, but rather than splitting all cellular components equally between mother and daughter, the daughter cells is made in peak condition while the mother cell retains much of the cell 'junk' like protein aggregates.
Hopefully that starts to answer your question.
The following is multiple choice question (with options) to answer.
What is an example of reproduction occurring in adulthood? | [
"humans are unable to reproduce until they are legal adults",
"eggs are unable to be fertilized before they are dropped",
"dogs are unable to have puppies until they are two years old",
"cats are unable to produce offspring until they are sexually mature"
] | D | reproduction occurs during adulthood |
OpenBookQA | OpenBookQA-300 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
Because of human logging activities, some animals have to conserve their | [
"air",
"water",
"legs",
"food"
] | D | when available resources decrease in an environment , organisms have to conserve those resources |
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