source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-4101 | zoology, psychology
Title: Fear in elephants It has been noted that elephants trained for war, as was done occasionally in earlier times, have still shown a tendency to panic in battle much more often when compared to a war horse trained for the same purpose. However, is this due to an innate quality of elephant behavior, or a result of poorer training methods due to humans simply having less experience training elephants than horses? Are elephants naturally more fearful creatures than horses or other beasts of war? I doubt if a comparison between these two animals in war situation is in order. These two animals serve different roles.
Here is a reference to an article in Wikipedia on War Elephants. Elephants have been used in war for thousands of years pretty effectively till the enemies discover their weakness and use it to their advantage. Making the elephant panic is one of the ways to counter them. Here is a list of methods from the above article:
Elephants had a tendency to panic themselves: after sustaining painful wounds or when their driver was killed they would run amok
One famous historical method for disrupting elephant units was the war pig......
At the Megara siege during the Diadochi wars, for example, the Megarians reportedly poured oil on a herd of pigs, set them alight, and drove them towards the enemy's massed war elephants. The elephants bolted in terror from the flaming squealing pigs.
It is for sure that many horses also panic in war situations. However a panicked elephant can cause more havoc than a horse. It appears that to prevent a panicked elephant from running amuck back into the ranks
The driver, called a mahout, was responsible for controlling the animal. In many armies, the mahout also carried a chisel-blade and a hammer to cut through the spinal cord and kill the animal if the elephant went berserk.
In recent times elephants in temple festivals in india do occasionaly panic and run amuck when the high explosive fire works are set of. However most of the elephants seem to tolerate it.
The following is multiple choice question (with options) to answer.
A ferret darting around a space in the wild in a panic is likely | [
"grooming itself",
"eluding foe",
"winning marathons",
"laying eggs"
] | B | some animals move quickly to escape predators |
OpenBookQA | OpenBookQA-4102 | 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.
Some animals escape predators by moving how? | [
"slowly",
"happily",
"briskly",
"steadily"
] | C | some animals move quickly to escape predators |
OpenBookQA | OpenBookQA-4103 | mechanical-engineering, structural-engineering, control-engineering
For example, if I wanted to setup such a facility, who would I have to consult?
You either find a consulting engineering firm with a lot of experience in designing and planning (and building!) such a plant. Or you find anexperienced hydroponics expert (the first bullet point) and a consulting firm with experience in a relevant field like wastewater.
Alternativly, you find a company specialized in building and selling hydroponics farms. This will give you less choice over the final plant - the company will want to work with their preferred components and concepts, and crucially they will want to reuse as much egnineering work from previous projects as they can.
The following is multiple choice question (with options) to answer.
If a person wants to help the environment, that person should | [
"leave the faucet open.",
"watch a lot of TV",
"reuse pieces of paper",
"buy a new car"
] | C | An example of recycling is using an object to make a new object |
OpenBookQA | OpenBookQA-4104 | materials, plastics
Title: Which material to use for athletic accessories? I'm looking for some guidance in selecting the right material for dance shoes heels and women's self-defense accessories.
I'm looking for a material that 1) has a superb strength-to-weight ratio, can withstand punishing and frequent impact, and very light (like plastic).
The part for the shoe will be very, very slender (stiletto heel), but will have to be able to endure hours of jumping, sliding, stomping, spinning, and skidding dancers… is compression strength the right term?
2) The material must also be safe to use as jewelry, so nothing toxic. Also, I am looking for something that tends to snap, rather than shatter, when it fails under pressure.
3) Lastly, it would be great if this material can be 3D printed, although that is not a must.
An inexpensive material would be ideal, of course, but I am open to learning about a fuller range of materials, including the more expensive ones. I am willing to consider a higher priced material if it will offer substantial value to the accessories in terms of strength, quality, and safety. For plastics, my first instinct for the first two properties would be a polycarbonate plastic. Polycarbonates are known to be very strong plastics (tensile strength up to ~70 MPa) and deform without breaking under many conditions, which is why they're commonly used in things like safety glasses and bullet-resistant glass. It also looks very interesting as it's quite optically clear. PC is 3D printable, I've seen a few people using it in hobby printers (http://www.protoparadigm.com/blog/2011/12/printing-polycarbonate/) and in very high end StrataSys printers, but it's not a super common material so it might take some experimenting.
Another option is a nylon. There are a number of different types available and many have similar properties to polycarbonates (minus the optical clarity). Nylons seem to be a bit more popular for 3D printing and I've heard good things about the Taulman filaments.
The following is multiple choice question (with options) to answer.
Which is likely the material used to make an eco-friendly sculpture? | [
"pollutants",
"animal furs",
"coke cans",
"fossil fuels"
] | C | An example of recycling is using an object to make a new object |
OpenBookQA | OpenBookQA-4105 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
In order for an animal to need to hibernate, they must be of the species that | [
"is in space",
"makes brownies",
"nothing",
"instinctively does it"
] | D | hibernation is an inherited behavior |
OpenBookQA | OpenBookQA-4106 | organic-chemistry, everyday-chemistry, experimental-chemistry, biochemistry, food-chemistry
Title: How Bread is made with yeast, sugar and luke warm milk? Materials and Apparatus:
wheat flour
sugar
dry yeast
glass bowl
covering plate
milk
Procedure:
Lukewarm milk is taken in the glass bowl and sugar is added to it. Then, yeast is added to the same.
The mixture is left undisturbed for 10-12 minutes to activate the yeast
3 cups of wheat flour are added to the bowl containing the milk mixture.
The mixture is mixed thoroughly with 100ml of added water and the dough is kneaded well
The dough is placed in a bowl, covered with a plate and left undisturbed for 2 hours.
My query/confusion:
Why is milk needed?
"activated yeast"- what's the difference?
Can yeast work without sugar or milk.
Detail out the stages of the anaerobic oxidative process which takes place as a common first step in both aerobic and anaerobic respiration.
Finally, feel free to share anything I may be missing which should be here.
If you have any confusion regarding what I want to ask, please ask in the comments. Please upvote if you are curious about it too
milk is not needed, 'pure' bread is without milk
yeast is a fungus, therefore, it is alive. Its best to work with fresh yeast, which you find as small cubes in the refrigerated section. This one does not have to be activated. non-fresh yeast is dried, so in order for it to work properly, it has to be undried by adding water, which is called activation.
and 4. As said before, milk is not needed. Sugar however is the food for the yeast, without it, it does nothing. In aerobic breathing, the yeast metabolizes the sugar as we would: sugar + oxygen -> water + CO2. Without oxygen, the yeast resorts to ethanol fermentation: sugar -> alcohol + CO2 (this is, why it is used to make beer or wine). For making bread, we have a mixture of both respirations, which does not really matter, since we are only interested in the CO2, which makes the dough fluffy =) But without sugar, there is no CO2.
The following is multiple choice question (with options) to answer.
Yeast deposited in an oven from a closet | [
"rises",
"compresses",
"falls",
"requires antifungal cream"
] | A | moving an object from a cool place to a warm place causes the object 's temperature to increase |
OpenBookQA | OpenBookQA-4107 | fluid-dynamics
Title: Feeling the Breeze This question is based on an odd phenomenon I noticed last week. Since then, I've been collecting more data to try to get an accurate picture of the facts.
Each morning, I go to my bus stop. It's on a main road, and when I get there, there is a lot of traffic. Every couple minutes a large truck goes by, and I suddenly feel a breeze go by me. The catch here is that there is about a one-second delay between the truck passing by and the start of the breeze. What is causing this phenomenon?
Here's some more information: I'm about three meters from the road; The breeze begins roughly one second after the truck passes by, and last for one and a half seconds; The breeze seems to be blowing diagonally, from my rear left to my front right side (I'm in America, so the trucks go from left to right); The breeze does not seem to depend on truck size (although small vehicles do not cause it).
I do have two possible explanations for the breeze:
1) The truck goes by at about 30 mph. This could create a tiny, short-lived vacuum at the back as it moves forward, thereby drawing air towards the rear of the truck.
2) The breeze is the result of some sort of "bow shock" from the truck.
Neither of these explanations seem to satisfy me, though, because they seem a bit far-fetched, and I am certainly no expert in fluid mechanics. What could be the cause of the breeze?
As a last note, I have no idea what tags to use for this question, because I don't know what the cause of the breeze is. Suggestions for these and other edits are welcome. What you're feeling there is the wake behind truck. As the truck passes through the air, it imparts momentum and generates quite a lot of turbulence (allowing it to impart even more momentum). It takes a little bit of time for that momentum to spread outward and reach you. As that air is 'pulled' behind the truck more will be drawn in from the sides. These two effects give the flow that left/forward direction that you feel.
The folks at Cornell have some nice animations and pictures of vehicle wakes.
The following is multiple choice question (with options) to answer.
Wind can | [
"feel emotions like love",
"turn a statue to dust",
"raise a family of four",
"have a baby child"
] | B | wind carries sand from one place to another place |
OpenBookQA | OpenBookQA-4108 | geography, geomorphology, satellites, satellite-oddities
Title: What produces these distinct shapes in the Rub' al Khali seen from space? update: Searching "Rub' al Khali Empty Quarter" found "Q2: What are sabkhas?" in
https://www.geocaching.com/geocache/GC6BYQ0_rub-al-khali-the-empty-quarter which seems to be related.
From the NASA image gallery; and also Catalog Page for PIA11084 where the caption says:
Original Caption Released with Image: The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.
The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.
The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.
Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team
Image Addition Date: 2008-08-08 The pattern shown in this image has an amazing amount of approximate repetition of shapes; long straight segments with a periodicity of about 2 kilometers, "stair steps" northward and sharp, pointy extensions southward. Is there any understanding how such a distinct pattern could be formed?
below: "Rub' al Khali (Arabian Empty Quarter) sand dunes imaged by Terra (EOS AM-1)" cropped and full sized (reduced resolution) images from here.
The following is multiple choice question (with options) to answer.
Which would likely displace a desert? | [
"sunlight",
"ant colonies",
"gale forces",
"bush men"
] | C | wind carries sand from one place to another place |
OpenBookQA | OpenBookQA-4109 | fluid-dynamics
Title: Feeling the Breeze This question is based on an odd phenomenon I noticed last week. Since then, I've been collecting more data to try to get an accurate picture of the facts.
Each morning, I go to my bus stop. It's on a main road, and when I get there, there is a lot of traffic. Every couple minutes a large truck goes by, and I suddenly feel a breeze go by me. The catch here is that there is about a one-second delay between the truck passing by and the start of the breeze. What is causing this phenomenon?
Here's some more information: I'm about three meters from the road; The breeze begins roughly one second after the truck passes by, and last for one and a half seconds; The breeze seems to be blowing diagonally, from my rear left to my front right side (I'm in America, so the trucks go from left to right); The breeze does not seem to depend on truck size (although small vehicles do not cause it).
I do have two possible explanations for the breeze:
1) The truck goes by at about 30 mph. This could create a tiny, short-lived vacuum at the back as it moves forward, thereby drawing air towards the rear of the truck.
2) The breeze is the result of some sort of "bow shock" from the truck.
Neither of these explanations seem to satisfy me, though, because they seem a bit far-fetched, and I am certainly no expert in fluid mechanics. What could be the cause of the breeze?
As a last note, I have no idea what tags to use for this question, because I don't know what the cause of the breeze is. Suggestions for these and other edits are welcome. What you're feeling there is the wake behind truck. As the truck passes through the air, it imparts momentum and generates quite a lot of turbulence (allowing it to impart even more momentum). It takes a little bit of time for that momentum to spread outward and reach you. As that air is 'pulled' behind the truck more will be drawn in from the sides. These two effects give the flow that left/forward direction that you feel.
The folks at Cornell have some nice animations and pictures of vehicle wakes.
The following is multiple choice question (with options) to answer.
After being driven, a car's hood feels | [
"furry",
"hotter",
"soft",
"cold"
] | B | a car engine is a source of heat |
OpenBookQA | OpenBookQA-4110 | meteorology, climate-change, precipitation, climate-models
Can this process predict changes in 1000-year events? Yes, potentially, even when the projection period is usually more like 100 years. This is because 1 in 1000-year events are actually defined inversely - that is, they are thought to have a 0.1% chance of occurring in any given year. If your ensemble projects over 100 years, but has 100 simulations, then there are 10,000 years in which that a 1 in 1000 might occur. If you see it occurring 20 times, or 4 times, then you might get suspicious that things are changing. You probably need more than that to get a statistically significant result, but there are ensembles out there that are really big (e.g. Stainforth et al, 2005, which had 2,578 simulations totalling over 100,000 simulated
years, and I think some of the ClimatePrediction.net have tens of thousands of simulations). Even without those large ensembles, if you assume particular distributions of extreme events where probability is a simple function of extremeness (e.g. Log-normal distribution or similar), then you can probably say something about large extremes based on the change in behaviour of less extreme events. Unfortunately, I am not aware of any experiments that look at the likely changes to very extreme events.
The following is multiple choice question (with options) to answer.
What usually occurs over a period of many years? | [
"tides",
"lightning",
"rock breaking",
"floods"
] | C | weathering usually occurs over a period of many years |
OpenBookQA | OpenBookQA-4111 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
A thing that is weathered from a large item to tiny items has existed for an amount of time over between | [
"a week and a month",
"a month and a decade",
"a day and some weeks",
"a minute and an hour"
] | B | weathering usually occurs over a period of many years |
OpenBookQA | OpenBookQA-4112 | earth, universe, big-bang-theory, fundamental-astronomy, space
Title: Why do we we even exist? It came to my mind one day that why does this universe even exist and why do we even exist and like we are enclosed in the so called atmosphere and a floating rock in space called the Earth, so is there any possibility that the universe is also enclosed in something and if it is, then what is outside that enclosure? That's an interesting question, but as the comments say might be a better place to ask this question in the Philosophy SE site, but the question about the universe being englobed maybe by another much bigger 'space' is something we might never be able to prove right or wrong. This 'existential' question might refer to the holograph theory, the multiverse theory. The thing is, at the moment the only possible explanation of whats beyond the 'observable universe' boundary is nothing, neon, an infinite multi-dimensional plane of nothingness.
The following is multiple choice question (with options) to answer.
we only have diamonds because of the existence of | [
"machines",
"large pressure",
"work force",
"carbonite"
] | B | heat and pressure change the remains of prehistoric living things into natural gas |
OpenBookQA | OpenBookQA-4113 | climate-change, carbon, water-vapour, greenhouse-gases
This doesn't really have much to do with your original question! If you want to ask about this, please go ahead and post a new question; StackExchange isn't a discussion site, and we try to keep each question focused on a single topic.
With this in mind, I'll just give a very brief answer here. Your formulation is a little inaccurate: the age of the dinosaurs spans at least 135 million years, there was a lot of carbon burial before it started, and all the carbon currently in the ground wasn't in the atmosphere at the same time. However, it is true that the Earth has seen higher CO2 levels than at present, and that much of that excess carbon is now locked up in fossil fuels. So what would happen if we put a lot of that carbon back in the atmosphere and tried to recreate the high-CO2 atmosphere that, say, T. rex breathed in the Late Cretaceous? Back then, the Earth was a lot warmer, with little or no ice at the poles. One of the biggest effects of re-releasing all that carbon would be the melting of our current polar ice sheets, raising sea levels by some tens of metres. The problem is not that the Earth will become completely uninhabitable by any life form whatsoever (although many current species will go extinct). The problem is that a lot of species, including Homo sapiens, are poorly prepared for a climate change of this magnitude. Ten percent of the world's human population and 8% of its urban land area is in low-elevation coastal zones, and would be completely submerged by a 10-metre sea-level rise -- which is still far less than the sea levels seen during the age of the dinosaurs.
Sea-level rise is just one effect among many, but for now I'll leave it at this since (as I mentioned above) this isn't related to your original question.
If a person cut his water intake in half, he will get sick before he can get fatter.
The following is multiple choice question (with options) to answer.
Which likely changed the remains of prehistoric living things into natural gas? | [
"air currents",
"fire",
"thunder",
"volcanic reactions"
] | D | heat and pressure change the remains of prehistoric living things into natural gas |
OpenBookQA | OpenBookQA-4114 | optics, vision
Title: Insides of eyelids and light People commonly see the insides of their eyelids and see a little amount of light and no amount of light of the insides of their eyelids depending on what environment they're in, What's the difference of seeing the amount of light of the insides of their eyelids? Your eyelids are partially transparent to light. In the presence of a strong light source, even with eyes closed some light will make it through. Usually it will be reddish after passing through the skin filled with blood vessels.
You may also see greenish, yellowish, magenta, or purplish images that fade after closing your eyes. These are called after-images and are the result of the chemicals in your retina resetting themselves after light is removed. They typically consist of cyan, magenta, and yellow which are are opposite colors of your cone receptors: red, green, and blue.
The following is multiple choice question (with options) to answer.
When light enters the eye through the pupil the light falls on the what? | [
"brain",
"optic disk",
"retina diagram",
"nose"
] | B | when light enters the eye through the pupil , that light falls on the retina |
OpenBookQA | OpenBookQA-4115 | 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.
A retina may be illuminated by | [
"moving animals",
"open circuits",
"dark bedroom",
"campfires"
] | D | when light enters the eye through the pupil , that light falls on the retina |
OpenBookQA | OpenBookQA-4116 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
Certain species of which type of animal gives live birth? | [
"Lizards",
"Snakes",
"Birds",
"Fish"
] | A | fish lay eggs |
OpenBookQA | OpenBookQA-4117 | ## The Attempt at a Solution
I tried to do 1. another way:
The probability that all theses events will occur: 1/4 * 1/3 * 1/2 = 1/24
1-(1/24) = 23/24
Obviously this is wrong. Is the reason it is wrong, because: the complement of "all of these events will occur" is that "not all of these events will occur," meaning, it is not "none of these events will occur."
None of these events will occur is included in the compliment 1-(1/24), but so is that 1 of the events occur, and that 2 of the events occur, etc.
Am I right in my reasoning?
Yes, that's it exactly.
Ray Vickson
Homework Helper
Dearly Missed
## Homework Statement
1.
Suppose that A, B, and C are 3 independent events such that Pr(A)=1/4, Pr(B)=1/3 and Pr(C)=1/2.
a. Determine the probability that none of these events will occur.
Is it just:
(1-P(a))(1-P(b))(1-P(c)) = 3/4 * 2/3 * 1/2 = 1/4
## The Attempt at a Solution
I tried to do 1. another way:
The probability that all theses events will occur: 1/4 * 1/3 * 1/2 = 1/24
1-(1/24) = 23/24
Obviously this is wrong. Is the reason it is wrong, because: the complement of "all of these events will occur" is that "not all of these events will occur," meaning, it is not "none of these events will occur."
None of these events will occur is included in the compliment 1-(1/24), but so is that 1 of the events occur, and that 2 of the events occur, etc.
Am I right in my reasoning?
The following is multiple choice question (with options) to answer.
Which is most likely to occur? | [
"a female fly lays eggs while it is a larvae",
"a male fly lays eggs while it is a larvae",
"a male fly lays eggs while it is an adult",
"a female fly lays eggs while it is an adult"
] | D | fish lay eggs |
OpenBookQA | OpenBookQA-4118 | 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 living animal is going to be in an ideal situation, at a minimum it will have | [
"a residence",
"a beating",
"a sled",
"a liver transplant"
] | A | an animal requires shelter |
OpenBookQA | OpenBookQA-4119 | # 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.
A dark cave fulfills what need for a wild, roaming grizzly bear? | [
"exercise for its health",
"shelter for its safety",
"food for it to eat",
"friends for some companionship"
] | B | an animal requires shelter |
OpenBookQA | OpenBookQA-4120 | thermodynamics, thermal-radiation
Title: Why don't gas flames radiate much heat directly, but metal objects heated by them do? Gas barbeque manufacturers place metal bars, ceramic plates or lava rocks above the gas burner so that they radiate more heat towards the grill. Cooking directly over a single gas flame just wouldn't work very well.
Why don't gas flames radiate much heat directly but a metal/ceramic object heated by the same flame does? For example, you can put your hand near a flame and not feel anything but lava rocks will scorch your skin easily. The luminous flame itself is hot; the site where the chemical process of combustion takes place. But the product of combustion, typically CO₂, H₂O, and perhaps some CO gas carry off a great quantity of the heat energy created in the reaction.
The main purpose of the lava rocks, grill etc. is to capture a good part of that heat flux so it doesn't just blow by the food into the atmosphere. Another reason is to provide a more uniform distribution over the cooking field.
The reason the lava rocks 'feel' hotter than the bare flame is that they have the capacity to store a lot of that heat. The flame and hot product gases transfer heat over time and that heat integrates over time to raise the temperature of the rocks.
The following is multiple choice question (with options) to answer.
Holding a hot dog over a campfire makes it | [
"carbon dioxide",
"vegan",
"a marshmallow",
"stiffer"
] | D | cooking causes a chemical reaction |
OpenBookQA | OpenBookQA-4121 | electromagnetism, electromagnetic-radiation, electric-circuits, electric-fields
Title: Confusion about energy transport in a circuit I have some confusions about how to imagine energy flow in a circuit. Imagine for example just a simple circuit with a battery, two wires and a light bulb.
According to classical Electrodynamics the energy is transported by the electromagnetic field outside the wires to the light bulb and we can describe the direction of energy flux by the Poynting vector.
So far, so good…
But I have a few questions at this point:
1.) A few sources emphasize that it is NOT the electrons that transport the energy to the light bulb but the EM waves. But when the EM waves hit the light bulb, the light and thermical energy is created by fast moving electrons or am I wrong? So it is not right say that electrons transport energy but it should be right to say that EM waves give the energy to the electrons and they vibrate and this kinetic energy is used?
2.) In addition to the first question: I am always wondering how does the field know where the light bulb is? The obvious answer would be: it doesn’t. But with that logic, the energy from the EM field should be at every point of the wire. Is that correct?
I am confused because pictures like this (https://i.stack.imgur.com/f9K80.png) only show the energy transport directly to the light bulb but shouldn’t the energy be transported everywhere?
I hope someone can clear up my confusion :)
Thanks in advance! The wave "knows" where the bulb is because the EM field is directed by the wires to the bulb: The H-field surrounds the wire, while the E-field is between the wires.
Experimentally, there is no way to prove that the "field" lights up the bulb and not the motion of the electrons. The reason behind this explanation is not this simple example of a bulb connected to a battery but that this example serves as a didactic introduction to energy transfer between antennas that are not connected by anything "material", as in a radio or cell phone communicating with a tower.
The following is multiple choice question (with options) to answer.
Which of the following likely make up a path for electrical energy to travel to a device? | [
"steel or copper",
"rice or beans",
"peaches or cream",
"cotton and solar"
] | A | a closed circuit has continuous path |
OpenBookQA | OpenBookQA-4122 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
Soil has everything a tree needs to | [
"develop",
"burn",
"die",
"move"
] | A | soil contains nutrients for plants |
OpenBookQA | OpenBookQA-4123 | 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.
Where does August take place during the winter? | [
"China",
"Zimbabwe",
"Canada",
"Iceland"
] | B | August is during the winter in the southern hemisphere |
OpenBookQA | OpenBookQA-4124 | climate, solar-terrestrial-physics
Title: Why is March colder than September in Northern Hemisphere? Forgive my ignorance of the subject but I was always wondered about the exact reason of this phenomenon.
Vernal equinox happens around March 20, whereas autumnal equinox happens around September 22, so wherever you are in Northern Hemisphere, the length of the day, and consequently the amount of solar energy that reaches the place should be almost the same.
However the average temperatures differ widely, for example Toronto has average temperatures of 2°C to 6°C on March 20th, and 14°C to 19°C on September 22nd. So around 12°C difference [link].
So obviously there is some sort of temperature inertia, as temperatures seem to experience a delay in responding to changes in day length.
What is the main reason for it? Is it effect of sea ice or snow-covered land albedo? Energy stored in oceans? Energy absorbed by melting snow and ice? The phenomenon is called seasonal lag.
There's a more extensive answer elsewhere on this site but the basic idea is that temperature lags behind insolation by several weeks, because it takes time to change the mean temperatures of the land, the atmospehere, and especially oceans change their mean temperature. This diagram tries to show the lag, along with various ways of reckoning the seasons:
The following is multiple choice question (with options) to answer.
If it's freezing in New Zealand than it's the what month | [
"January",
"December",
"August",
"February"
] | C | August is during the winter in the southern hemisphere |
OpenBookQA | OpenBookQA-4125 | physical-chemistry, nanoscience
Title: What Makes Diamonds Difficult to Produce? Having seen an answer over on Worldbuilding about very strong/dense wood that suggested artificially creating some enzymes that would manufacture diamond/graphene as the cellular binding materials in the tree, I said to myself, "Hold on, I know this won't work: creating diamonds requires high temperature and/or pressures...doesn't it?"
But I was unable to locate any information as to why this is the case: that is, what physical property of the bonds or arrangement of the carbon atoms dictates the intense pressures needed to cause the formation of the crystal lattice? Or is there really nothing standing in the way of a chemical process (i.e. an enzyme constructing it a few atoms at a time, albeit with large energy expenditures and slow timescales) that would do it other than "we don't know how to make that."
The covenant bond energy between two carbon atoms seems pretty high, I'll admit, at 348 kJ/mol, but it's less than some other bonds, say Carbon and Hydrogen at 419 kJ/mol (source). So it doesn't seem like that's the limiting factor. I do know that there is energy stored in the organization of the lattice itself, but I don't know how much that contributes; Wikipedia only helpfully notes that the energy is "greater in materials like diamond than sugar."
The following is multiple choice question (with options) to answer.
diamonds exist because of the existence of | [
"raw carbon",
"work force",
"plant feeding",
"machines"
] | A | if something is a raw material then that something comes directly from a source |
OpenBookQA | OpenBookQA-4126 | material-science, elasticity, continuum-mechanics, stress-strain
In short, once you properly glue the bottom of the cube to the floor, you can expect something more similar to what visible here
rather than in the picture above.
It is just funny that sketches like the one above are so widely used to explain shear stress. I think it is kind of risky and can lead to inconsistencies and (legitimate) doubts in students, I wonder how many persons are aware.
I have to say that some texts indicate the presence of vertical external forces also on those two lateral surfaces (then it all works and the uniform deformation above is correct)... but more often this is neglected.
The following is multiple choice question (with options) to answer.
Sarah has one piece of wood that is smooth and polished and another that is rough and unfinished. Which of the following is true? | [
"both pieces of wood will create the same amount of friction",
"the unfinished wood will generate more heat than the other while rubbed over the floor",
"the rough wood will more easily move when rubbed over the tile than the finished wood.",
"the finished wood will generate more heat when it is rubbed back a... | B | as the roughness of something increases , the friction of that something will increase when its surface moves against another surface |
OpenBookQA | OpenBookQA-4127 | c#, game
// if we're the beginning of a wall...
if(isWallStart)
{
// If there are no X intersections here, add an edge
if(corners1 == 0) geo.add(vec3(px1, py1a, pz), vec3(px2, py1a, pz), vec3(px1, py1a, pz + wallHeight), vec3(px2, py1a, pz + wallHeight), 0, 1, 0, 1, edgeMat);
}
else
{
ty1a = py1;
ty1b = py1;
}
// if we're at the end of a wall...
if(isWallEnd)
{
// If there are no X intersections here, add an edge
if(corners2 == 0) geo.add(vec3(px2, py2a, pz), vec3(px1, py2a, pz), vec3(px2, py2a, pz + wallHeight), vec3(px1, py2a, pz + wallHeight), 0, 1, 0, 1, edgeMat);
}
else
{
ty2a = py2;
ty2b = py2;
}
// top
if(!walls.Y.exists(x, y, z + 1))
{
geo.add(vec3(px2, ty2b, pz + wallHeight), vec3(px1, ty2a, pz + wallHeight), vec3(px2, ty1b, pz + wallHeight), vec3(px1, ty1a, pz + wallHeight), 0, 1, 0, 1, topMat);
}
The following is multiple choice question (with options) to answer.
A brick wall stops | [
"lumens",
"monster trucks",
"wrecking balls",
"bulldozers"
] | A | no light shines through an opaque object |
OpenBookQA | OpenBookQA-4128 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
seed dispersal is when the seeds of a plant are moved from the plant to a new what? | [
"planet",
"bus",
"page",
"locale"
] | D | seed dispersal is when the seeds of a plant are moved from the plant to a new environment |
OpenBookQA | OpenBookQA-4129 | electrostatics, symmetry, gauss-law, coulombs-law
Yes in principle. Not known in practice.
If we observed deviation of the field from spherical symmetry, we would tend to expand the notion of the source and seek something else that is asymmetric that can fit that role. For example, effective gravity field on Earth is not perfectly radial and also gravity is weaker on the Equator. We managed to find plausible additional source - rotation of the Earth and Earth oblateness. But if we found asymmetric gravity field on a perfectly spherical planet that does not rotate and there is no other visible source, we could, in accordance with scientific methodology, conclude that Newton's gravity law is not universal and in some cases, the gravity field can have transverse components. However, many people would not like that, and would try to introduce invisible gravity source that would save the old law and explain the asymmetry.
The following is multiple choice question (with options) to answer.
If the source of a bean is very far away, and the bean becomes a source for another, separate bean, then the original bean was | [
"a bad seed",
"a dispersed seed",
"a fresh shell",
"a meaty liver"
] | B | seed dispersal is when the seeds of a plant are moved from the plant to a new environment |
OpenBookQA | OpenBookQA-4130 | release energy by transferring heat to their surroundings. In older works, power is sometimes called activity. the bungee cord has more potential energy when it is stretched out than when it is slack. , green plants convert solar energy to chemical energy (commonly of oxygen) by the process of photosynthesis. Practice questions A bowling ball is lifted to a height […]. kinetic energy = mass * velocity² / 2 E = m * v² / 2. The maximum energy stored in the inductor is LI2/2 with I = I MAX. Efficiency can be explained as the amount of work done by an object to the total energy spent. You can think of a trebuchet as a see saw! Yes, a see saw is really all that a trebuchet is. Example of Few questions where you can use this Mechanical Energy Formula calculate the Mechanical energy of the object have mass 10 kg and velocity 3m/s and height above the ground is 10 m calculate the Kinetic Energy,Potential energy and Mechanical energy of the object have mass 1 kg and velocity 2m/s and height above the ground is 50 m. Kinetic energy = Joules Kinetic Energy Calculator is a free online tool that displays the kinetic energy of the object. Contribute to Ghostlydestinypolice/Physics_Energy development by creating an account on GitHub. We cover most electrical devices and home appliances, our online calculators can be edited to fit any home appliance and accurately calculate power costs. 2 Kinetic Energy. Current (I) is measured in amps (A), using an ammeter. The units of power are watts, the units of energy are joules. The kinetic energy just before impact is equal to its gravitational potential energy at the height from which it was dropped: K. 94u2rotkh0qgw ts2269o179 taplsbcnrzp02 tqj6cos4hnt038 862fohcw5vw 0kib5khqvn7x7u imx0rwjjl87j 7v6n0lvam9qps6 1ep3ku4gpb4 7jfyw1bfipc qndzw85umfgmg 3hdpzbzs6my yeu4magtr0k3kw0 e9wp756pxxgsa
The following is multiple choice question (with options) to answer.
Which is a source of kinetic energy? | [
"Endurance",
"Motion",
"Velocity",
"Speed"
] | B | motion is a source of kinetic energy in an object |
OpenBookQA | OpenBookQA-4131 | 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.
John's dog seemed to be getting chubby. He concluded that | [
"the dog was sleepwalking.",
"the dog was getting more exercise",
"the dog was overindulging in meals and snacks",
"the dog was refusing to eat"
] | C | as the amount of food an animal eats increases , the weight of that animal will increase |
OpenBookQA | OpenBookQA-4132 | biochemistry, molecular-biology, fat-metabolism, carbohydrates
Title: What is the source of the fat in adipose tissue? I have heard the opinion that all of it comes from de novo lipogenesis of carbohydrates, but I'm skeptical. Is there evidence either way - either that dietary fat definitely gets stored in the adipose tissue, or that it never does, and all of it is from carbohydrate transmutation? The proximal source of adipocyte lipids is mainly fatty acids from circulating lipoproteins (1) after hydrolysis by lipoprotein lipase (LPL).
LPL is activated by ApoC-II, which is present in hepatic-originating VLDL and IDL lipoprotein, but also chylomicron of direct dietary source. Insulin, secreted after meals, stimulates LPL production by adipocytes.
Thus the ultimate source of these lipids is both hepatic lipogenesis (from other substrates like glucids) and dietary fats.
Lipid transport in blood, for reference purpose (Michal G. Schomburg D., Biochemical Pathways, 2012)
The following is multiple choice question (with options) to answer.
Which would make an animal fat? | [
"a canary drinking water",
"a cat having too much perch",
"a rice plant getting too much sun",
"a dog running freely"
] | B | as the amount of food an animal eats increases , the weight of that animal will increase |
OpenBookQA | OpenBookQA-4133 | thermodynamics, visible-light, lenses
I forgot to mention that you can't heat the sample beyond about $5500\,K$ (which is the temperature of a black body that best fits the spectrum we receive at sea level). Of course, you need to know what you're doing to get anywhere close to this temperature.
The following is multiple choice question (with options) to answer.
A source of heat could be | [
"a cold soda",
"an ice cube",
"a mini flashlight",
"snow"
] | C | a radiator is a source of heat |
OpenBookQA | OpenBookQA-4134 | thermodynamics, thermal-conductivity
Title: Thermal Heat Transfer I work for a large plant bakery and we have recently coated the inside steel walls of our very large oven with a reflective coating. I have taken temperature readings inside the insulation void and there is a noticeable decrease.
What I am trying to do is quantify the theoretical energy savings in LPG usage from this.
It's been quite some years since I ever tried to calculate anything like this and I am in dire need of some guidance. Is Fourier's Law the right direction to be taking with this?
E.G $\dfrac{Q}{T}= \dfrac{KA(T1-T2)}{D}$
$=\text{Thermal conductivity of oven wall} \times \text{surface area of walls}\left(\frac{\text{temp before painting-temp after painting}}{\text{thickness of wall}}\right)$.
Some more background information:
Heat is generated from an LPG burner located centrally in the oven. It is a large swing tray style oven measuring $6$ meters wide by $25$ meters. The reflective coating is a silver heat stable paint on the inside of the oven, before this they were black with carbon. The oven has $2$ steel layers with insulation in between them - temperature readings were taken from inside the insulating cavity.
Thanks in advance In this problem all three modes of heat transfer occur:
radiative
conductive
convective
Firstly, we assume the furnace operates in steady state, so that all heat generated by the LPG burner dissipates away through the furnace's wall. In that case, all temperatures are constant in time.
Also I'll approximate the furnace by a single wall with surface area $A$ and thickness $\Delta x$.
We can write, for steady state:
$$Q_{in}=Q_{out}$$
Now we distinguish $3$ zones, I, II and III:
Left of the $T$-axis is the heat source ($Q$), right the wall with surface area $A$ and thickness $\Delta x$.
Radiative zone (zone I):
The following is multiple choice question (with options) to answer.
If a person is choosing to be near a metal heat source, normally located on a building's interior wall, then that person | [
"is combusting",
"is too hot",
"desires warmth",
"is on fire"
] | C | a radiator is a source of heat |
OpenBookQA | OpenBookQA-4135 | orbit
Title: Traveling constantly towards West. That is clockwise If I travel against against the Earth's rotation. Say once around the world. I will always see sunrise and never a sunset
Is that accurate? If you travel west so quickly that you go around the world in one day (24 hours) then the sun will remain almost fixed in the sky. You will see neither a sunrise nor a sunset. At a latitude of 45 degrees north, you will need to travel at 1180 km/h (faster than a commercial jet, nearly Mach 1)
If you travel less quickly, then the sun will move from East to West, but rather more slowly. You may see multiple sunrises and sunsets, depending on your speed.
If you travel faster, the sun will move from West to East in the sky. Again, you may see multiple sunrises and sunsets, but the sun would rise in the West.
The following is multiple choice question (with options) to answer.
You wake up north of the equator, and you notice the sunrise happening earlier than yesterday and later than the day after, what day could it be | [
"Feb. 21",
"Dec. 21",
"Sep. 31",
"May 21"
] | B | the winter solstice is on December 21st in the northern hemisphere |
OpenBookQA | OpenBookQA-4136 | earth, the-sun
Title: Latest sunrise/earliest sunset out of phase with solstice? Everybody knows that the shortest and longest days of the year occur on the solstices. However, examination of sunrise/sunset tables shows that the maxima and minima of sunrise/sunset times are offset from the solstices by about 10 days.
According to timeanddate.com for my location (Portland, OR), for the winter solstice, the earliest sunset is about December 10 (16:27), and the latest sunrise is around January 1 (07:51).
This is counterintuitive... what's the explanation? The point here is that sunrise and sunset does not only move towards or away from noon, but noon itself moves around 12:00. There is a difference between "civil time" (the one counted by wall clocks) and "solar time" (the one marked by sun clocks). This difference is called the "Equation of Time" and its geometrical shape is called the Analema.
So in order to have the earliest sunset you need a combination of both a short day and a noon moved before 12:00. Same reasoning for latest sunrise.
You can see more about the Equation of Time on Wikipedia: http://en.wikipedia.org/wiki/Equation_of_time
The following is multiple choice question (with options) to answer.
In which of these locations is the winter solstice on December 21st? | [
"Panama",
"New Zealand",
"South Africa",
"Argentina"
] | A | the winter solstice is on December 21st in the northern hemisphere |
OpenBookQA | OpenBookQA-4137 | computational-chemistry
Lordstryker already posted in the comments, that it might be done by hand with chemcraft. I tried that and it is not very satisfying. One produces too many errors.
Are there any other programs/scripts that might be able to produce these files? As of today I decided to add an answer to this problem to declare it as unresolved. The answer of Klaus only answers the part of visualisation, which is not what I want or need. There are at least ten different programs that can do that.
While turbomole comes with the built-in functionality of screwer, other program packages might not have that. The mentioned XVibs is more than outdated.
The solution LordStryker added in the comments, doing it with the ChemCraft software is workable but highly ineffective and may introduce many errors.
I will certainly come back, whenever I find a program capable of this, but until further notice: *There is no such thing.
The following is multiple choice question (with options) to answer.
Duracell's convert chemicals to | [
"ocean current",
"sunlight",
"magic",
"voltage"
] | D | batteries convert chemical energy to electrical energy |
OpenBookQA | OpenBookQA-4138 | evolution, species
Title: Reasons why living fossils exist?
A living fossil is a living species (or clade) that
appears to be similar to another species otherwise known only from fossils,
typically with no close living relatives.
A living fossil is considered as a successful organism, which has made its way through many major extinction events. Also, the morphology of living fossils resemble some species of organisms which we know only through their fossil remains.
What is the reason for a particular type of species to become a living fossil; is the engineering of this particular species extraordinary, in that it can survive any selection process encountered thus far?
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Have these organisms modified themselves, so that currently their morphology seems to be similar to a fossil organism? One part of your question betrays a serious error:
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Actually the reverse is true; constancy of form can only be maintained in the presence of continuous selective pressure. It's just that this is stabilising selection that acts to maintain the existing form rather than push the organism to new morphologies. In fact, most selection acts in this manner. This shouldn't surprise you: organisms are typically well adapted to their environments so changes are more likely to reduce fitness than increase fitness.
It's also worth noting that although living fossils show little morphological change they can continue to show change at the molecular level at rates as high as, or higher than, other organisms - e.g. (May et al 2007; Cao et al 2013).
The following is multiple choice question (with options) to answer.
Every one of these would be considered a fossil but what? | [
"a mammoth bone that has been turned to rock",
"the imprint of a sea creature in a rock found on a mountain",
"a cave full of old drawings",
"a paw print in a rock"
] | C | An example of a fossil is a paw print in rock |
OpenBookQA | OpenBookQA-4139 | geophysics, sedimentology
Title: Does dirt compact itself over time? If so, how does this happen? If I were to bury something 10 feet (~3 metres) underground, with loose soil on top, would the ground naturally compact itself over time, until whatever I had buried has dirt tightly pressing against it on all sides?
What if I buried it 50 feet (~15 metres) underground?
If it exists, what is this compaction process called and how does it happen? Soil is a collection of various sized minerals grains, of various types of minerals produced by the weathering of rock. Typical soil minerals are clays, silts and sands.
The properties and behavior of different soil types depends of the composition of the soil: the proportion of clays, silts and sand in a soil. Sandy soils are well draining and clayey soils are sticky.
Between the grains of minerals that comprise a soil are spaces, called pores or pore spaces. The pores can be filled with either water or air, depending the location of water tables and wetting events like rain, snow melts or other forms of water inundation.
The density of a soil is dependent on the degree of compaction of the soil. For to a soil to be compacted, a stress has to be applied to the soil to realign the grains of soil which reduces the total volume of the pores and reduces the amount of air within the pores.
Consolidation of a soil occurs when pore space is reduced and water in a soil is displaced due to an applied stress.
Regarding having something buried and soil compacting around it over time, yes that will occur but it is a question of how much stress the soil experiences, the duration of time and the nature of the soil - sandy or clayey. Something buried for a day without any stresses not much will happen. But, something buried for thousands of years with people and animals walking over it, rain falling on the soil, vibrations from nearby human activity and an occasional earthquake all add to the stresses the soil will experience and increases the degree of compaction or consolidation over time.
The following is multiple choice question (with options) to answer.
When liquefied soil flows over carcasses and drys it will become | [
"lakes",
"diamonds",
"bubbles",
"fossilized"
] | D | fossils are formed when layers of sediment cover the remains of organisms over time |
OpenBookQA | OpenBookQA-4140 | thermodynamics, entropy
The tree dies, which is pretty irreversible (entropy grows at the cell scale, because cells are ordered structures when they are alive while the atomic structure remains similar because you don't let the tree rot). For this part you can actually approximate the tree as being a closed system.
Processing the tree to make the house and furniture. After reading about how the process of making wood works, I would say that you have to cut and throw away a substantial part of the initial tree (without producing any change on its atomic structure), so that the entropy of the remaining part is notably less than the initial one.
All the other processes involved (such as the form of the furniture and house, or the placement of these) are subleading.
Thus, accepting that the house has less entropy than the tree, there is a lot of entropy generated in the second process above, so that the net entropy of house + woodcuter + rest of the tree (useless to make the house) + heat is bigger than the intial entropy of the tree.
The following is multiple choice question (with options) to answer.
If a tree is cut down what will happen to it? | [
"vitality extinguishing",
"growth",
"vigor",
"life"
] | A | if a tree is cut down then that tree will die |
OpenBookQA | OpenBookQA-4141 | With[{icv = {{0, 0.4082401254164024, 0, 0},
{0, 0.24008038662195985, -0.15316368171208566, 0.28838672839135326},
{0, 0.24352018790129148, 0.09848498536170303, 0.3135210500944904},
{0, 0.20788819727584018, 0.18687849877360435, 0.3047456328865395},
{0, 0.11124773284074371, 0.24234454959281115, 0.32410152798705066},
{0, 0.09612790055948518, 0.2562151235263743, 0.32091473672760257},
{0, 0.14504873906640348, 0.2433184249171519, 0.3098719090788399},
{0, 0.21466692008332666, 0.21341797098009158, 0.2855018063099425},
{0, 0.2242200636897092, 0.21057030870037158, 0.27976766448196655},
{0, 0.3683386516212832, 0.18778901046261137, 0.011696534024095057},
{0, 0.3451153373835715, 0.23762310035771178, 0.005962392196119196},
{0, 0.33504538978074816, 0.256132905175892, 0.0016617858251372995},
The following is multiple choice question (with options) to answer.
A supermodel with a big nose probably | [
"ate an animal with a big nose",
"had a parent also with one",
"didn't pay the photographer enough",
"ate dog food a lot"
] | B | when both a dominant and recessive gene are present , the dominant trait will be visible |
OpenBookQA | OpenBookQA-4142 | optics, power, fiber-optics, solar-cells, technology
Title: Are large scale optical power delivery systems feasible? I am attending an introductory course of optics and photonics and we just started to study optical fibers for digital communications. However, I have started wondering about using optical fibers to transmit energy. I have done some research on the internet and I have found some insights on power-over-fiber technologies but there isn't really a lot of material, so here I am.
Is power-over-fiber a technology which in the future can be develop in order to compete with electrical power transfer or there are physical limits?
As far as I know we have an efficent device to convert electrical to optical power, namely the laser. Optical fibers can transmit power with an attenuation as low as 0.18 dB/Km which seem pretty good to me. Maybe the problem can be the efficency of photodiodes at the end of the line?
P.S.
I'm in the final year of my bachelor degree course in Engineering Physics and I'm trying to understand which technologies are likely to be developed in the future in order to invest my time studying something promising. There are several practical limits to power-over-fiber.
The first is absorption: even the best fibers have some limited absorption, so at high power levels they will get hot.
The next is power conversion: even after you have transmitted power over the cable, turning it into something useful (electricity) will incur a significant loss of efficiency.
Finally, there is spontaneous Brillouin scattering (SBS): at sufficiently high power densities, optical media become nonlinear and this will lead to spontaneous conversion of some of the optical power to phonons. Quoting from the RP photonics encyclopedia:
SBS introduces the most stringent power limit for the amplification and the passive propagation of narrow-band optical signals in fibers.
That same link explains the mechanism in more depth. SBS puts an upper limit on the power you can send through a fiber, regardless of the losses you can tolerate.
The following is multiple choice question (with options) to answer.
What material can be used to transmit power to a light bulb? | [
"plastic",
"metal",
"wood",
"cloth"
] | B | some light bulbs convert electricity into light and heat energy |
OpenBookQA | OpenBookQA-4143 | botany, marine-biology, salt
Title: Mangroves and desalination of sea water I am not an expert but I guess that mangroves (or some other plants that thrive in sea water) perform some kind of desalination to extract fresh water from sea water.
Is this true? If yes, What biological mechanisms are used to remove salt from sea water?
I am interested in any research about biological desalination. This paper might be of interest to you: https://advances.sciencemag.org/content/6/8/eaax5253.
The researchers created a synthetic mangrove that actually performs desalination, using the principles of natural mangroves.
The introduction has a good overview of the main ways mangroves desalinate saline water, namely:
Physical blockage by suberin within cells walls
Selective permeability of cell membranes in root
Negative pressure caused by evaporation that acts as hydraulic pressure to cause take-up of water by roots
All these combine to turn the mangrove into a kind of natural RO (reverse osmosis) machine.
The following is multiple choice question (with options) to answer.
What is often brackish in an estuary? | [
"water wheels",
"fish",
"air",
"h2o"
] | D | water is often brackish in an estuary |
OpenBookQA | OpenBookQA-4144 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
A thing that may be weathered when a plant lays down roots is | [
"bird feathers",
"human legs",
"dirt driveway",
"ocean waves"
] | C | An example of weathering is when a plant root grows into a crack in rock |
OpenBookQA | OpenBookQA-4145 | evolution, ornithology, ethology, sexual-selection
Bateson P. 1978. Sexual imprinting and optimal outbreeding. Nature 273, 659 - 660.
Bereczkei T, Gyuris P, Weisfeld GE. 2004. Sexual imprinting in human mate choice. Proceedings of the Royal Society of London, Series B: Biological Sciences 271: 1129–1134.
Immelmann K. 1972. Sexual and Other Long-Term Aspects of Imprinting in Birds and Other Species. In Advances in the Study of Behavior, Vol. Volume 4 of, pp. 147–174, Academic Press
The following is multiple choice question (with options) to answer.
Finches love | [
"jokes",
"magic",
"Everyone Love Raymond",
"sweet sultan"
] | D | a skinny beak is used for obtaining food by a bird from small spaces |
OpenBookQA | OpenBookQA-4146 | food, nutrition, energy-metabolism
Title: What are the bare minimum nutrients required to survive as a human? I am trying to determine the bare minimum nutritional requirements to survive as a human, ignoring energy (caloric) requirements. Another way to ask this question is: What elements can humans not live without? I am not inquiring solely about what nutrients are needed, but also their approximate amounts.
Imagine pills that a person can take that covers all their base nutritional needs and that after taking this pill the person can eat whatever they want to meet their caloric requirements. Hypothetically, this pill could have some amount (how much?) fat, carbohydrates, protein, fiber, minerals, and vitamins, and the person could subsequently eat any other food to meet their caloric requirements knowing their nutritional needs would already be otherwise met. Lets ignore the possibility of the person suffering from health issues due to eating too much of any specific food to meet their caloric requirements (e.g., taking the magic pills and then eating only butter).
A person in this situation could think "Ok I've got most of my bases covered, now I just need to ingest another 1000 calories of (almost) anything I want).
What nutrients are absolutely necessary for humans to survive indefinitely, and how much of these nutrients are required?
I am hoping for a complete list with approximate amounts (e.g., 20g fat, 20g carbohydrates, 1mg Vitamin X, .05mg Vitamin Y, 10mg mineral X). Essential nutrients include (NutrientsReview):
Water
9 amino acids: histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, tryptophan, threonine, valine
2 fatty acids (alpha linolenic and linoleic acid)
Vitamins: A, B1, B2, B3, B5, B6, folic acid, biotin, B12, C,
D, E and K (and choline, which is considered a vitamin-like substance)
Minerals: calcium, chromium, chloride, copper, iodine, iron,
manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc
The following is multiple choice question (with options) to answer.
What requires nutrients to grow? | [
"birds",
"metals",
"computers",
"dirt"
] | A | a skinny beak is used for obtaining food by a bird from small spaces |
OpenBookQA | OpenBookQA-4147 | python, beginner, game, functional-programming, adventure-game
ending_opportunity = '\n' + '''1 December 2029. After a few weeks of trying to rebuild you realize that reconstruction. You can't go back your old community beacuse there is
nothing there. So now your stuck. You went scavenging earlier before the tornado and found a living space that could keep a person going for months. However, it keeps ONE person
going for months. You are left to decide if survival is really that important. ([ABANDON]X} {B[PERSERVERE])''' + '\n> '
ending_abandon = '\n' + '''You left your community, with no leader, to die in exchange for your comfort. The community is irate and you will be killed on first sight if found.
Luckily, just before your food and supplies ran out, you found another community and you had few problems. You lived there for the rest of your life.''' + traitor
ending_perservere = '\n' + '''One by one, everyone fell out. With no necessities, your community died out. You where seen as loyal for sticking with your community until the end.
Nice one chief.'''
ending_terrorism = '\n' + '''6 February 2029. Mr. Powell is back and he is out for revenge from losing the election. He and his militia are destroying everything and everyone in
sight until he gets what wants. With only a few minutes before he arrives at your city hall, you and your army must decide to ([ATTACK]X} {B[RETREAT])''' + '\n> '
ending_attack = '\n' + '''You and your remaining army fought ferociousy against the bigger opposition. In the end, you won, but at a cost, destroyed the whole city. Few survived
being admist the exchange of explosives and gunfire. Your city is decimated but you stopped a major threat from taking over. It took two years before conditions returned to
normal'''
ending_retreat = '\n' + '''You most peaceful decision and left with your most trusted peers. You wandered off into unknown and eventually fit in with another community. A few
The following is multiple choice question (with options) to answer.
After a storm | [
"drinking water will be in short supply",
"ponds may dry out",
"creek beds may be spilling over",
"flowers will wilt and wither"
] | C | as dryness increases in an environment , the available water in that environment will decrease |
OpenBookQA | OpenBookQA-4148 | Hey, thanks for your help guys. For a minute there, I thought that this theoretical person could not safely expect to live to be 82 years old.
9. Jun 16, 2012
### SW VandeCarr
In fact, on a purely probabilistic basis, for any finite time no matter how large, there is a non zero probability that a person would survive that long. So for a sufficiently large population, there would be a theoretic person that would live 100,000 years. This, of course, has no basis in biology.
In terms of the probability of being murdered, the model would not hold for the 100,000 year old person. In terms of the model, probably the best one can do is assume the proportion of causes of death would be constant. The calculation above needs to be corrected for overall survival in terms of death from any cause.
Last edited: Jun 16, 2012
10. Jun 16, 2012
### viraltux
Interesting... but 0.37% is not that small percentage, don't you think? That means, roughly speaking, that a community of around 300 persons can expect that one of them will be murdered.
If you consider that the number of people we know plus acquaintances can easily be around 300 persons that would mean that most 82 year old persons know of someone in their circles who has been murdered. Mmm... that might be an interesting survey.
11. Jun 16, 2012
### SW VandeCarr
As I said in my previous post, this is a misapplication of statistics. You have to consider survival in terms of all cause death. If you just consider the murder rate, then at some point nearly everyone gets murdered.
12. Jun 16, 2012
### moonman239
I know that.
This person will not die until he reaches age 82, if he is not murdered. As mentioned before, this person has a 68% chance of living to be 82.
13. Jun 16, 2012
### D H
Staff Emeritus
The probability of living to 82 per this problem is 99.63%, not 68%. You missed the decimal point on the 0.37%.
14. Jun 16, 2012
### SW VandeCarr
The following is multiple choice question (with options) to answer.
What would thrive if Eagles died out | [
"air",
"hamsters",
"emotions",
"magic"
] | B | as population of predators decreases , the population of prey will increase in an environment |
OpenBookQA | OpenBookQA-4149 | 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.
a decline in the number of predators often leads to | [
"a rise in the number of prey",
"an increase in breeding between predators",
"a decline in the number of prey",
"a decrease in breeding between prey"
] | A | as population of predators decreases , the population of prey will increase in an environment |
OpenBookQA | OpenBookQA-4150 | curvature, earth, education
I do not have a goal of proving something to this date. I see that mentioning her might have been confusing. Yet, before this meeting I was certain about the shape of the earth - but her words (even though I think she's incorrect in her beliefs) made me realize that my certainty was based on the assumption I have not really questioned. So sitting on a beach with another friend of mine (both being ball-believers) we thought of a simple check to confirm our certainty, rather than to convince anyone else in us being right.
I am only looking for the check that would confirm the GLOBAL shape of the earth being ball-like. There were several brilliant answers to another question that worked as a local curvature proof, and I am not interested in them.
I am looking for the the answer that will show that the Earth is ball-shaped (or rather an ellipsoid), not that it is not flat. There are many other great shapes being neither ball/ellipsoid nor flat. I do still have an assumption that this shape is convex, otherwise things can go too wild and e.g. projections on the Moon would not help us.
The following is multiple choice question (with options) to answer.
If our earth is anything, it is this | [
"alien",
"nearest to Pluto",
"frozen solid",
"mountainous"
] | D | the surface of the Earth contains mountains |
OpenBookQA | OpenBookQA-4151 | evolution, mutations, antibiotic-resistance
Title: If bacterial resistance randomly occur, then why limit broad-spectrum antibiotic use? If there is importance to study some discipline, then one of the main matters is its applications, so besides the primary goal of knowing the truth of the matter regarding what that discipline is investigating, applicability or usefulness of that study in other fields or in the field itself is a very important matter. I'll direct my attention here to Evolution, and its mechanisms. So accordingly if something that I personally want to come up with is application of that knowledge to the field of my work.
In reality we don't study evolution extensively at college level in medicine, since it doesn't have a direct clinical impact on the diagnosis and treatment of patients in most of the cases. However, one possible area of interaction is "bacterial resistance to antibiotics", since this is related to "mutations", and generally viewed as a mechanism whereby the bacterium adapts to its environment.
Now all of my life in medicine from college through specialty and academic teaching, we've never ceased being reminded about not dispensing antibiotics liberally, and the main concern outlined is "emergence of resistant strains of bacteria" due to this liberal use of antibiotics itself. There are other reasons of course, like side effects and cost, but they are not the main concern most of the times.
During my recent review of Evolution, looking at the introductory courses that were cited to me by many participants here, in particular this page of Evo101 titled "Mutations are Random" I was really shocked to know that even the mutations that resulted in bacterial resistance were not "directed mutations", i.e. it is not the case that the exposure to the antibiotic caused the bacteria to have that mutation in the first place, actually the page mentions Esther and Joshua Lederberg experiments showing that those resistant bacteria were already there before the population was exposed to the antibiotics?
So why have we been always reminded by bacteriologists of limiting our antibiotic usage if emergence of drug resistance is not due to exposure to it?
The following is multiple choice question (with options) to answer.
As bacterial resistance to antibiotics rises, the ability of medical professionals to | [
"prescribe anti-anxiety and sleep aids will increase",
"treat non-bacterial infections in humans will decrease",
"treat bacterial-related conditions in humans will decrease",
"treat problems of the digestive system in humans will increase"
] | C | as the resistance to something increases , how easilty that something can be done will decrease |
OpenBookQA | OpenBookQA-4152 | electricity, potential
What if you had a giant bird that is so big, its two legs could span the whole power line, even without stretching? Resistance is proportional to length, but inversely proportional to thickness. So if the bird was well-proportioned, it would have the same resistance as a small bird. However, now the resistance of $R_{wire}$ is non-trivial - many kilometers of even very conductive wire can have significant resistance. As said earlier, if 100 A passes through the power line, the bird need only get 0.1% of that to be at risk of death, so if the bird is long enough to span enough kilometers of power line that the resistance of the line is at least a few $k\Omega$, it will experience a very dangerous shock. Although a bird that big would also have other problems, such as the square-cube law, or current going through its head to make lightning in the upper layers of the atmosphere.
The following is multiple choice question (with options) to answer.
as the resistance to something increases , how easily that something can be done will do what? | [
"rise",
"fly",
"plummet",
"soar"
] | C | as the resistance to something increases , how easilty that something can be done will decrease |
OpenBookQA | OpenBookQA-4153 | earthquakes, soil-science, bedrock
Title: Question regarding underground man-made facilities Why is it that underground facilities (or underground military bases) are almost always built into hollowed out mountains? Examples of (publicly known ones anyway) are Cheyenne Mountain Complex and Mount Weather government/ military facilities. Is having a highland/mountain a prerequisite for construction of military/government facilities? Is is not possible to construct facilities beneath lower ground, plains, dessert or under cities, besides subway stations and tunnels? Say if we wanted to build NORAD bunker somewhere deep beneath San Jose population centers, is this possible discounting the fault lines and permits for now? This question is not about earth science. If anything, it has more to do with engineering.
Strategic or critical defense or government infrastructure needs to be protected against explosive attacks, particularly nuclear attacks. A mountain offers a sizeable protective cap/roof to an underground installation. Similar levels of protection can be provided in flat ground, but the underground installation would need to be significantly deeper.
Critical parts of the installation would not be established within the mountain above the level of the ground surrounding the mountain; it would be established below.
Additionally, many mountains are composed on igneous rock: rock that solidified from a molten mass. Such rock, such as basalt or dolerite (diabase), is typically stronger than sedimentary rock and can thus offer better blast protection than sedimentary rock.
Also, if the installation is established igneous rock, the same strength parameters can also mean reduced geotechnical and subsequent ground support measures would be required for the underground voids that if they were established in sedimentary rock.
Cheyanne Mountain is composed of granite, and igneous rock that solidified while still underground. The NORAD installation within Cheyanne Mountain "was designed to ride out a nuclear attack". Having been completed in 1966, when tunnel boring machines were not a consideration, it was established using drill and blast methods and consumed 500 tons of explosives.
The following is multiple choice question (with options) to answer.
Living underground can be used for hiding from what? | [
"food",
"hunters",
"dirt",
"water"
] | B | living underground can be used for hiding from predators |
OpenBookQA | OpenBookQA-4154 | botany, plant-physiology
Title: Can any plant regenerate missing tissue? I have not yet found a plant that, when an insect eats a hole in one of its leaves, it can regenerate the lost tissue. Many plants will grow a new stem if the old one is cut, but it is not a perfect regeneration, and has no likeness in form to the previous stem. Are there any plants that can, even to a degree, regenerate missing tissue? In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as different cells of the leaf, or vascular cells). Later growth (of, say, a leaf) is largely a result of cell expansion (although cell division does still occur, but drops off as the leaf expands). Therefore, if you punch a hole in a leaf, it probably won't be filled in because the cells in that leaf have finished growing and dividing.
However, as a shoot grows, more meristems are created. These are found in the axillary buds, just above where the leaf meets the stem. The meristems in the axillary buds can grow to form branches. Different plants obviously make different numbers of branches, but there is a common control mechanism known as apical dominance, where the meristem at the tip of the shoot suppresses the growth of the lower axillary buds. This is why a shoot with no branches can be made to grow branches by cutting off the tip (gardeners often do this to make "leggy" plants more bushy).
All of that was a long explanation to say, no, a plant doesn't normally^^ regenerate in the sense of filling in cells that have gone missing. However, if you cut off a shoot, the next remaining bud might begin to grow and, in a sense, replace the part that was lost. In that case, an existing bud is recruited to form a new branch and replace lost functionality, but I wouldn't say that qualifies as regenerating missing tissue.
^There are other types of meristem as well.
The following is multiple choice question (with options) to answer.
During a prolonged shortage of water, a tree's ability to add extra tissue and grow thick rings is slowed and the tree produces | [
"wider growth rings",
"thinner growth rings",
"more leafy growths",
"annual scar tissue"
] | B | as the amount of available water decreases , tree-growth rings will become narrower |
OpenBookQA | OpenBookQA-4155 | seismology, earthquakes, seismic-hazards, drilling
Title: Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes? The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (link)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (link)--let's assume it is 100 km.
That said, if a seismic station is installed at a depth of 50 km, and there are many of them in any given metropolitan area, then we can have a warning that is tens of seconds before the earthquake reaches the surface.
While I realize that drilling down to 50 kn is no easy task, I would have imagined that saving human life is well worth the efforts. Why hasn't this been done so far? Is it that such a short notice (10s of seconds) isn't worth it? The simple answer is that you can't drill to 50 km depth.
The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific drilling project. The very few others were oil exploration boreholes.
Drilling that deep is extremely expensive and hard. If you go and ask anyone who ever worked on a drill rig, drilling the second 100 metres is always harder than the first 100 metres. And we're talking about kilometres here! There are several problems with drilling that deep. It's extremely hot down there, and the drilling equipment just breaks and stops working. You also need to pump cooling water in and pump out the stuff you're drilling and it gets harder with depth.
This is simply not feasible. Now let's say that you did somehow manage to drill a hole to that depth. How would you put monitoring equipment inside? That equipment has to sustain heat and pressure and still keep working, while being able to transmit whatever it's reading back to the surface. This is not going to happen, not at 50 or 10 km depth.
Another problem is that not all earthquakes are that deep. Some earthquakes originate near the surface, or just several km deep. Having a monitoring station down there isn't going to help. The 2011 Tohoku earthquake (the one that triggered the tsunami at Fukushima) was only 30 km deep. Same thing for the 2004 Indian Ocean earthquake.
The following is multiple choice question (with options) to answer.
Being near buildings or houses is the worst spot to be when there is an earthquake as you are likely to be | [
"stones",
"nothing",
"kissed by one",
"crushed by one"
] | D | buildings collapsing often cause death |
OpenBookQA | OpenBookQA-4156 | evolution, natural-selection, theoretical-biology
Title: Probability of Extinction under Genetic Drift Here is the Wright-Fisher model of genetic drift:
$$\frac{(2N)!}{k!(2N-k)!}p^kq^{2N-k} \Leftrightarrow \binom{2N}{k}p^kq^{2N-k}$$
where $\binom{2N}{k}$ is the binomial coefficient.
This formula gives the probability of obtaining $k$ copies of an allele at generation $t+1$ given that there are $p$ copies of this allele at generation $t$. $N$ is the population size and $2N$ is the number of copies of each gene (this model applies to diploid population only).
From this formula, how can we calculate the probability of extinction of an allele in say 120 generations starting at a given frequency, let's say 0.2?
and
How can we calculate the probability of extinction rather than fixation of an allele present at frequency $p$ if we wait an infinite amount of time? update
The answer is here!
The following is multiple choice question (with options) to answer.
If an organism dies then the population of that organism will what? | [
"lessen",
"skyrocket",
"rise",
"grow"
] | A | if an organism dies then the population of that organism will decrease |
OpenBookQA | OpenBookQA-4157 | pie. Let \$$\mathcal X\$$ be the \$$\mathbf{Cost}\$$-category where the objects are the elements of \$$\mathbb N[S]\$$ and \$$\mathcal X (x, x')\$$ is the time it takes to turn the list of ingredients described by \$$x\$$ into the list of ingredients described by \$$x'\$$ or \$$\infty\$$ if this is impossible. Some examples: $\mathcal{X}( [\textrm{flour}] + [\textrm{water}] + [\textrm{butter}], [\textrm{crust}]) = 30$ $\mathcal{X}( [2\textrm{flour}] +2 [\textrm{water}] + 2[\textrm{butter}] + [\textrm{filling}] , [\textrm{crust}] + [\textrm{pie}]) = 120$ $\mathcal{X}([\textrm{pie}], [\textrm{pie}]) = 0$ $\mathcal{X}([\textrm{water}], [\textrm{pie}]) = \infty$ Now suppose I am a busy person who prefers to buy my pie crust from the store instead of making it from scratch. Now the set of ingredients I need to make a pie is \$$T = \\{\textrm{crust}, \textrm{filling}, \textrm{pie}\\}\$$. I can create another \$$\mathbf{Cost}\$$-category \$$\mathcal{Y}\$$ where the objects are the elements of \$$\mathbb{N}[T]\$$ and \$$\mathcal{Y}(y, y')\$$ is again given by the time it takes to make transform the ingredients of \$$y\$$ into the ingredients of \$$y'\$$. Lastly we need to define a \$$\mathbf{Cost}\$$-functor \$$F:
The following is multiple choice question (with options) to answer.
A piece of pizza is placed within a box and becomes this when something is conducted throughout the box into the food: | [
"toasted",
"meaty",
"frozen",
"cool"
] | A | thermal conduction is when materials conduct heat through those materials |
OpenBookQA | OpenBookQA-4158 | thermodynamics, heat-transfer, thermal-conduction
Title: Relationship between thermal conductivity and reaching the steady temperature? The diagram is for three materials with different thermal conductivities. I think number 1 is the material with higher thermal conductivity because it transfers the heat faster so it gets to the steady temperature sooner than the other two. Am I right? If not or if my reasoning isn't correct, I appreciate your help. $\dot{Q} = k A \frac{\Delta T}{l}$
$l$ thickness
$A$ surface area
From this follows that besides other factors the rate of heatflow is proportional to the thermal conductivity $k$.
$\dot{Q} \propto k$
Therefore a high thermal conductivity allows for a fast heat transfer, hence your interpretation that a fast change in temperature correlates with a high thermal conductivity is right.
The following is multiple choice question (with options) to answer.
Thermal conduction is when materials conduct what through those materials? | [
"air",
"hotness",
"electricity",
"cold"
] | B | thermal conduction is when materials conduct heat through those materials |
OpenBookQA | OpenBookQA-4159 | thermodynamics, evaporation, gas, liquid-state
On the water surface, knowing the temperature, we can estimate the vapor pressure and vapor mixture fraction. Then there will be an diffusion process for the water vapor to move out and for the ambient air to move in. Because the water surface doesn't allow the air to further move, a circulation forms. When the water vapor moves out, the water vapor pressure drops, so more liquid water evaporates to fill up the loss of water vapor. The evaporation associates latent heat so water surface area temperature drops (you may see dew on the bowl wall). Then a heat transfer process starts which may initiate water circulation as well.
As this is complex, doing test might be a quick way to get the K value if you assume it is a constant, which is questionable.
The following is multiple choice question (with options) to answer.
Water will become vapor quicker in | [
"Jupiter",
"Earth",
"Mercury",
"Neptune"
] | C | the sun causes water to evaporate more quickly by adding heat |
OpenBookQA | OpenBookQA-4160 | hydrology, water, rainfall, groundwater
Title: How much time does water takes to reach to the ground? I want to understand the phenomena where water droplets after precipitation reaches to the ground.
How much time does it take to become ground water or in other words how much time is taken by water to recharge the ground after rain.
I am assuming the water droplets falls in the plain having no concrete human constructions. It depends upon the hydraulic conductivity, the degree of saturation, and the depth to water table. Generally, water seeping down in the unsaturated zone moves very slowly. Assuming a typical depth to water table of 10 to 20 metres, the seepage time could be a matter of minutes in the case of coarse boulders, to months or even years if there is a lot of clay in fine sediment. Under saturated conditions, the water might move a lot faster. Other factors include the configuration of the wetting front, the unsaturated storage, temperature, and the hydraulic gradient. So basically, there is no simple answer - it's all a matter of the local hydrogeology.
There is no substitute for local measurement - water levels in an observation bore, in the case of water table conditions, or tensiometry in the case of the unsaturated zone.
The following is multiple choice question (with options) to answer.
When would a puddle get smaller and disappear the fastest? | [
"on a snowy day",
"on a day without clouds",
"on a cloudy day",
"on a dark day"
] | B | the sun causes water to evaporate more quickly by adding heat |
OpenBookQA | OpenBookQA-4161 | europa
So, with the combined information from these sources, I would stand by a figure of somewhere between 15-28 km. The reason I don't go any higher is because I don't see an error bound or range of values in the paper's abstract - it just says "approximately 28 km thick" - and the full paper is unfortunately behind a paywall. As the paper's abstract says, there are local heating phenomena that could occur and cause the crust to vary in different places, which could explain why the figure isn't that precise. The reason I don't go any lower, on the other hand, is because that NASA FAQ didn't specify any exact values for their mention of "few kilometers thick", and didn't provide much explanation as to why those said scientists supported that idea.
The following is multiple choice question (with options) to answer.
If the crust of a planet is adjusted in short order, a likely culprit is | [
"moons",
"quivers",
"night",
"logs"
] | B | an earthquake changes Earth 's surface quickly |
OpenBookQA | OpenBookQA-4162 | astronomy, telescopes
Title: Fall/Winter Viewing I live in Seattle and am thinking of purchasing a telescope. Is fall/winter a decent time of year for viewing (aside from summer)? Are there any major viewings/events during that this of year?
I know I live in a city of rain, but there are some nice nights. The sky is a constantly changing tapestry of interesting sights and events: there is no time better than any other. If you''re interested, now is the best time!
Because of our location in the Milky Way Galaxy, summer and winter are the best times for viewing objects within the galaxy: open clusters and nebulae. Spring and fall are the best times to view objects outside our galaxy: globular clusters and other galaxies. Because of the Earth's rotation, if you stay up late, you can also get a sampling of the next season. Look at the autumn galaxies this evening, then stay up past midnight to view the winter clusters and nebulae.
Superimposed on the "deep sky" are the solar system objects, which operate on their own clock. Right now, Saturn is disappearing in the west at sunset but Venus will soon replace it; Jupiter rises around 10 p.m. and dominates the rest of the night. Mars is still far away in the morning sky, but is gradually getting closer.
The following is multiple choice question (with options) to answer.
In December in the northern hemisphere you need | [
"short shorts",
"cooling fans",
"suntan lotion",
"mittens"
] | D | December is during the winter in the northern hemisphere |
OpenBookQA | OpenBookQA-4163 | electrical-engineering, measurements, safety, photovoltaics
This has to be done ideally asap, but definitely before the end of May. Although, again, my main concern is doing this safely first and foremost. I am willing to hold off on measuring the power as long as there's as the primary concern is discharging power safely then figuring out how to measure power. I imagine that would involve routing power to a grounding rod, but I'm not sure.
Any advice and feedback is greatly appreciated, and I am happy to answer any questions.
Solar panel link: https://www.amazon.com/Renogy-Monocrystalline-Solar-Compact-Design/dp/B07JXYTFF7/ref=sr_1_1?dchild=1&keywords=Renogy+Solar+Panel+2pcs+100+Watt+12+Volt+Monocrystalline%2C+2-Pack+Compact+Design&qid=1619041063&sr=8-1 Long story short, probably the safest and cheapest way to measure while maximizing the output of the panels is to buy a small inverter which is connected to the internet and logs the data at a cloud, and connect the inverter to the grid.
On the grid almost nobody will notice the excess energy (probably they won't mind either, unless you are on some net metering scheme).
The other option is to connect - to the output of the inverter - some sort electrical resistance heating unit - preferably with twice the required input (e.g. for the 900W install a 2kW), which is properly cooled (maybe with a fan or otherwise)
The following is multiple choice question (with options) to answer.
A person who is working on setting up power for their cottage will avoid | [
"installing new power outlets",
"working on their wiring",
"installing electrical wires in walls",
"standing in a puddle"
] | D | water is an electrical conductor |
OpenBookQA | OpenBookQA-4164 | meteorology, geomorphology, climatology, atmospheric-circulation
Source Commons Wikipedia.
The cold waters near the ocean surface results in a cool, stable coastal atmosphere. In this region, evaporation from the ocean is reduced and produces extremely low rainfall over land. Precipitation is limited to morning fog and produces some of the driest ecosystems on Earth. The Atacama desert is the best example of such environment with average rainfalls of 15 mm/year (the driest non-polar region). In some areas, they are trying to take advantage of the little moisture the fog (Camanchaca) brings to establish some agricultural zones. The fog droplets are too small (1-40 micrometers) to form water drops and precipitate, so they use fog-catchers to collect moisture from the fog.
Source: newatlas.com
The following is multiple choice question (with options) to answer.
What environment has low rainfall? | [
"tropics",
"sandy zone",
"sandbox",
"forests"
] | B | a desert environment has low rainfall |
OpenBookQA | OpenBookQA-4165 | adaptation
Title: How do longleaf pine trees adapt to the florida keys rainforest? I know that longleaf pine trees can be found in rainforests, but I can't find anything. This is sort of a too broad question but here are a few ideas. The second most fragile part of plants are the leaves. In the latitudes and elevations that experience freezing, plants have learned to abscise their leaves and go dormant for the winter season. Conifers have thick, waxy, very thin leaves that most conifers do not need to shed.
In a rainforest there is no danger of too cold temperatures. That is why there is an abundance of broadleaf trees and plants in the rainforest. Most of our indoor plants are tropical rainforest species.
There is also an awful lot of rain in a rainforest. There is a problem with leaves covered with water, as it inhibits the absorption of CO2. Beneath the leaf, O2 is released as a by-product of photosynthesis. Broad leafed plants that have adapted to an environment with lots of rain, little wind, and being crowded together have leaves designed to 'wick' the rain water off the leaf to run down the midrib and off the pointy tip or lobed or curled under leaf margins. This clears off the water and allows the plant to take up CO2, or it would not be able to do photosynthesis to make its own food for energy.
The other cool thing I can remember, is that broad leafs of plants are able to 'adjust' to the light. Similar to a 'solar sail' in outer space. If in full sun, those leaves get thick and stay smaller. If in shade, very normal in a rainforest, those leaves can thin and get larger in order to capture as much light as possible.
A better wording for your question would be, 'why is there an abundance of broad leaf species versus conifers in a rainforest'? If I've been able to translate your question correctly?
Hope this helps.
The following is multiple choice question (with options) to answer.
Which type of vegetation could you find in areas with low rainfall? | [
"sunflowers",
"cacti",
"rose bushes",
"palm trees"
] | B | a desert environment has low rainfall |
OpenBookQA | OpenBookQA-4166 | astrophysics, angular-momentum, rotational-dynamics, quantum-spin, conservation-laws
Title: Why does each celestial object spin on its own axis? AFAIK all the celestial objects have a spin motion around its axis. What is the reason for this? If it must rotate by some theory, what decides it's direction and speed of rotation?
Is there any object that does not rotate about its axis? In general yes, everything rotates. It is to do with something called angular moment. Gravity is the central force in the Universe, because it is the only one which has a significant pull over large distances. When things collapse under their own gravity in space (i.e. clouds of gas and dust), any small amount of asymmetry in the collapse will be enough start it spinning. Even if it spins by a tiny amount, as it collapses, angular momentum conservation will mean it spins more and more quickly - just like an spinning ice-skater pulling their arms into their body and spinning more quickly. This means that all coherent masses are spinning - e.g. asteroids, neutron stars, galaxies, quasars.
The Universe is a complex place so something may be slowing down (because the gravity of other objects is putting on the brakes) or some things may appear not to be rotating (e.g. the Moon rotates but at the same rate as it goes around the Earth).
Huge clouds of gas and dust tend not to be spinning as a whole because they are expanding to fill the available volume - like a bad smell in room! - and not necessarily gravitational bound together. However they might have little pockets which start are turbulent, collapse under their own gravity, spin and form stars.
The following is multiple choice question (with options) to answer.
What rotates on its axis? | [
"oceans",
"winds",
"blue world",
"people"
] | C | the Earth rotates on its axis on its axis |
OpenBookQA | OpenBookQA-4167 | evolution, species
Title: Parents that eat their own children I am told that there are some species, like fish or rabbits, that if let, will eat their own children. If this is true, how does a species like this exist? Shouldn't the fact that they kill their own lineage make them nonviable? Yes, it is true.
Prairie dogs
Prairie dogs for example are known for frequent infanticides.
Many other species kill their babies too
But of course, such behaviour also exists in other lineages such as grey langurs, gerbilles, lions, giant water bugs and Bottlenose dolphins (just to cite a few examples).
How does that evolve
It will be impossible to provide a complete universal explanation to this behaviour because the evolutionary processes causing this behaviour varies from lineage to lineage. For examples, in lions, only males kill young of the females that are still nursing and they do so when taking over a new harem only. In prairie dogs, mothers cause infanticide preferentially on others' babies but also on their own babies.
Going into the details of how such behaviour evolves in every specific lineage would probably require writing an intro on kin selection and other fields of evolutionary biology which is way too much for a single post. You may want to have a look at the wikipedia article infanticide for a start.
Shouldn't the fact that they kill their own lineage make them nonviable?
Of course, they don't kill all the babies. Only a fraction of them!
The following is multiple choice question (with options) to answer.
The animals that never migrate never do so because they were born | [
"with the instinct",
"are too lazy",
"seventeen",
"without the instinct"
] | D | migration is an instinctive behavior |
OpenBookQA | OpenBookQA-4168 | the-sun, space, stellar-atmospheres
However, when you have something the Sun or even fog, the optical depth varies with the distance you're looking into that object. I'll talk about fog since it's familiar, but the same idea applies to the Sun's atmosphere. Say you're standing in a forrest and its very foggy out. There's a tree 1 meter away from you that you can see. You could measure your optical depth, $\tau$, of the fog between you and tree and might find that $\tau = 0.15$. Since $\tau$ is less than one, that implies you can see the tree, but the value of $\tau$ also implies how well you can see it. If $\tau = 0$, there's nothing between you and the tree to impede your ability to see it. Let's say there's another tree that's 5 meters away. Now there's more fog between you and the tree and while you can still see it, it is harder to see it. The optical depth of the fog between you and the tree 5 meters away might be $\tau = 0.75$. It's still less than one, implying the tree is visible, but because there's more fog between you and the tree, the optical depth is higher. Finally, there may be a tree 10 meters away with so much fog between you and the tree that the optical depth is $\tau = 1.5$. You can't see this tree because there's too much fog in the way. Hopefully you now realize that anything which is at a distance where $\tau > 1$ is not visible to you. That effectively defines a "surface" around you precisely when $\tau = 1$. Anything beyond that point is not visible and anything closer is visible.
If you're talking about the Sun, you can look at the Sun, but you'll only see light which originates from a point where $\tau < 1$. There are countless photons bouncing around inside the Sun, but you can't see them because they're in an opaque part of the Sun. Astronomers use the optical depth as a metric for defining the "surface" of the Sun.
The following is multiple choice question (with options) to answer.
Naomi looks around outside on a prairie and it is cloudless but the sun is nowhere to be seen. It is | [
"night",
"noon",
"morning",
"afternoon"
] | A | if it is night then the sun has set |
OpenBookQA | OpenBookQA-4169 | the-moon, the-sun
Title: Sunrise and Moonrise time are same I checked an app and saw that today, the sunrise and moonrise time are almost same. The sunset and moonset time are also same.
Why does this happen?
I have always known that moon rises at night and sets at dawn. That's called New Moon and happens roughly once a month.
It's when (viewed from earth) the moon, circling the earth, is in the same direction as the sun. So, by rotation of the earth, both become visible (sunrise/moonrise) and invisible (sunset/moonset) at roughly the same time.
Moon is then hardly visible for two reasons:
The back side of the moon is lit by the sun, the side facing to us does not get sunlight.
The moon is visibly rather close to the sun, so sunlight will blind the human eye when looking in that direction.
Two weeks later, we have Full Moon, the moon is opposite to the sun, it rises when the sun goes down and goes down when the sun rises, meaning that it's visible at night. And the side facing us gets full sunlight, so the moon becomes a very bright object on night sky.
The following is multiple choice question (with options) to answer.
When the sun is set it is called what? | [
"sleep time",
"noon",
"morning",
"dawn"
] | A | if it is night then the sun has set |
OpenBookQA | OpenBookQA-4170 | combinatorics, packing
In the end, there are only items of weight at most $10K(n+1)$ (now, forget about the previous terminology and call such items small) and items of weight at least $3M - 10K(n+1)$ (call them big). As per gnasher729 answer, small items can be easily distributed to the bins in the end, because $10K(n+1) < 3M/2$. Unfortunately, we cannot ignore
small items, because they affect $3S$ (the total weight of items) and, therefore, the sizes of the bins.
Fortunately, we know from the above manipulations that we can move all small items to the third (not almost full) bin. Hence, we are left with the following problem: there are $m$ big items with weights $3M - v_1$, $3M - v_2$, $\ldots$, $3M - v_m$, where $v_1 \leqslant v_2 \leqslant \ldots \leqslant v_m \leqslant 10K(n+1)$. There are also $n - m$ small items with total weight $R = 3S - (3Mm - V)$, where $V = v_1 + \ldots + v_m$. The exact weights of small items is not important.
There is barely any difference between weights of big items, because $10K(n+1)$ is negligible when compared to $M$. Moreover, the total weight of small items is also negligible. Because otherwise we could do something similar to the way we proved that all items are either big or small: we can pick small items (remember that they are all in the third bin) until their total weight exceeds $20K(n+1)$ for the first time (at such a moment, their total weight will exceed $20K(n+1)$ by at most a weight of a single small item; in other word, it will be in the range $[20K(n+1), 30K(n+1)]$) and then swap all these items with a single big item from the first or the second bin.
The following is multiple choice question (with options) to answer.
An item that might have more tightly packed matter is | [
"helium",
"gold",
"orange juice",
"wood"
] | B | matter with variable volume and shape assumes the shape and size of its entire container |
OpenBookQA | OpenBookQA-4171 | cell-biology
Title: Structure of Cell Are cells spheres or ovals/circles bound by phospholipidbilayer?
If they are spherical how are we able to see the nucleus through the phospholipid bilayer under a microscope? Not exactly. That is a stereotype of cells. Muscle cells are not round nor oval, but rather elongated rods. If you were to look up epithelia cells, you can quickly see that cells are grouped based on their physical characteristics; simple (round/oval & single layer), columnar, and cuboidal to name a few. Cells come in many shapes and sizes. As Hans stated, stains are vital in viewing cellular components. There is a diverse amount of stains used - which all carry a purpose and benefit in a specific application.
The following is multiple choice question (with options) to answer.
Cells can make up components of prisons, jails, holding areas and | [
"lifeforms",
"space stone",
"blue jeans",
"filtered water"
] | A | a living thing is made of cells |
OpenBookQA | OpenBookQA-4172 | 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.
migration is when what move to different locations in an annual cycle? | [
"animal figurines",
"sedentary animals",
"habitual creatures",
"currents"
] | C | migration is when animals move to different locations in an annual cycle |
OpenBookQA | OpenBookQA-4173 | species-identification, zoology, ornithology
Title: Identification by tail feather I saw the remains of a bird today I did not recognize, and it was pretty mangled so it was hard to describe it. It was about the size of a robin. However, it had a dark brown mottled body like nothing I have ever seen. I have included below a tail feather from the bird which is 5 inches long. I am sure it is not a thrush or a woodcock or a kestrel. So what was it?
Location is Great Bay, Portsmouth, New Hampshire, United States. I believe this is a tail feather (or retrix) from an adult male eastern whip-poor-will (Antrostomus vociferus). See right image below (click to zoom):
.
Source: USFWS Forensics Laboratory
Details:
The brown, mottled appearance and the size (~12 cm) match that of the OP's specimen.
A great resource for exploring bird feathers: https://www.fws.gov/lab/featheratlas/
The whip-poor-will's breeding grounds include the OP's location (i.e., New Hampshire), and according to All About Birds this species could still be present even late in the year ("they seem to leave between early September and late November.").
Orange is breeding. Source: All About Birds.
The whip-poor-will is a medium sized bird and similar in size to an American robin.
Whip-poor-will: 22-26 cm ; Robin: 20-28 cm
Eastern whip-poor-will, (c) Paul Cools, source: inaturalist
The following is multiple choice question (with options) to answer.
A goose in the autumn is most likely | [
"nesting",
"hibernating",
"in flight",
"laying eggs"
] | C | migration is when animals move to different locations in an annual cycle |
OpenBookQA | OpenBookQA-4174 | orbital-motion, solar-system, celestial-mechanics, chaos-theory
On predicting eclipses
The issue of chaos becomes even more extreme when trying to predict eclipses, particularly solar eclipses. The Sun, Jupiter, and Venus have marked effects on the long-term behavior of the Moon's orbit. Even more importantly, however, the Moon is receding from the Earth due to tidal interactions, and this rate is not constant. The current recession rate is about twice the average rate over the last several hundred million years. Changes in the shape and interconnectivity of the oceans drastically changes the rate at which the Moon recedes from the Earth. The melting of the ice covering Antarctica and Greenland would also significantly change the recession rate, as would the Earth entering another glaciation. Even a small change destroys the ability to make long term predictions of the Moon's orbit.
NASA developed a pair of catalogs of solar eclipses: one covering a 5,000-year period spanning from about 4000 years ago to about 1000 years into the future; the other a 10,000-year catalog of solar eclipses spanning from about 6000 years ago to about 4000 years into the future. The accuracy of these catalog degrades drastically before 3000 years ago and after 1000 years into the figure. Beyond these inner limits, the path of the eclipse over the Earth's surface becomes markedly unreliable, as does the ability to determine whether the eclipse will be partial, total, annular, or hybrid. At the outer time limits of the longer catalog, whether an eclipse did / will occur begins to become a bit dubious.
Because of the Earth's much larger shadow, predictions of lunar eclipses are a bit more reliable, but not much. The problem is that of exponential error growth, which is a characteristic of dynamically chaotic systems. Predictions of lunar eclipses more than a few tens of thousands of years into the future are more or less nonsense. The millions of years asked in the question: No.
The technique of orbital averaging once again can be of aid in determining characteristics of the Moon's orbit (but not position on the orbit). This can be augmented by geological records. Various tidal rhythmites give clues as to the paleological orbit of the Moon. A few rock formations exhibit layering that recorded the number of days in a month and the number of months in a year at the time the rock formation was created.
References
The following is multiple choice question (with options) to answer.
When the moon orbits our planet | [
"ocean levels rise and drop",
"rivers flow in the opposite direction",
"all living things go to sleep.",
"sea levels stay the same"
] | A | the gravitational pull of the Moon on Earth 's oceans causes the tides |
OpenBookQA | OpenBookQA-4175 | newtonian-mechanics, fluid-dynamics, acceleration, simulations, power
For your fan, air far away is still. It accelerates as it is sucked in, and slows down as it blows away. When it is far enough away, it is going so slowly that it might as well be still.
The amount of air passing through a fan in a given time is proportional to $v$, the velocity of the air. Said another way, the time it takes a given amount of air to pass through is inversely proportion to $v$.
The kinetic energy of the moving air is $E = 1/2mv^2$. Obviously, air moves at different speeds in different places. But suppose you double the air speed. The air in the fan will double its speed. As the air leaves the fan, it spreads out. But at each place, it is approximately true that it will go twice as fast as it did before. You can reasonably expect that if you double the speed through the fan, that all the moving air will double its speed, at least to some level of approximation.
This tells us something important. We can either take some sort of average $v$, or we can consider the energy of each piece of moving air. Either way, we find that
$$Power = \frac{Energy}{Time} \propto \frac{v^2}{1/v} = v^3 $$
So to double the air speed, the fan needs 8 times the power. $Power \propto v^3$ will be the most important part of your simulation.
The following is multiple choice question (with options) to answer.
Which causes the electric fan to work? | [
"the blades run themselves",
"power outlets allow the blades to rotate",
"the air pushes the fan",
"power outlets allow the fan to think"
] | B | the vanes rotating in an electric fan causes air to move |
OpenBookQA | OpenBookQA-4176 | object-oriented, ruby, unit-testing
Take the proposed test above that verifies that the tree doesn't keep growing after its death. The test is still only using the public #height method/accessor. Since it's failing, you'll want to do something. You can add whatever logic you want to the public or private methods; when the tests pass, you know you've fixed that particular issue. No need to specifically test the private methods.
There's also just basic decoupling. Since private methods aren't meant for consumption, and should be able to change radically, as long as the public interface stays intact. For instance, since you're not testing private methods right now, you could rewrite the class as below, and your current tests would still pass just fine.
class OrangeTree
LIFESPAN = 15
FRUIT_BEARING_AGE = 3
ORANGES_PER_YEAR = 3
The following is multiple choice question (with options) to answer.
Eureka lemon trees gain 12-24 inches in the spring due to | [
"snow",
"rain",
"darkness",
"the moon"
] | B | as the amount of water received by a plant increases , that plant will usually grow |
OpenBookQA | OpenBookQA-4177 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
A patch of thistle grows larger when this is increased: | [
"dampness",
"yeast",
"flour",
"milk production"
] | A | as the amount of water received by a plant increases , that plant will usually grow |
OpenBookQA | OpenBookQA-4178 | physical-chemistry, phase
Title: Properties of plasmas In chemistry one can recognize that the four states of matter are solid, liquid, gas and plasma. The first is rigid, and has a definite shape and volume. The second doesn't have a shape, and assumes the shape of its container, but it has a fixed volume. The third doesn't have either a shape or a fixed volume and assumes the volume and shape of its container. What about the fourth one (plasma)? Plasma is made up of ionized gas, so molecules have a positive electric charge and valency electrons are totally or partially separated by their nuclei.
Plasma is different from a gas since it has a high temperature and is radiation emitting; think of the Sun and other stars, which are made up of plasma and show both these properties.
Plasma hasn't got a proper volume, like gases; e.g. stars can expand or contract under the opposite effects of gravity and nuclear fusion. For example, this property is important to comprehend the formation of white dwarfs and neutron stars, process caused by high pression due to gravity.
Little trivia: there is also a fifth state of matter, whose name is Bose-Einstein Condensate (BEC).
The following is multiple choice question (with options) to answer.
matter in the liquid phase has what shape? | [
"circle",
"adaptable",
"triangle",
"square"
] | B | Matter in the liquid phase has variable shape |
OpenBookQA | OpenBookQA-4179 | Remark $\$ This is a special case of ubiquitous multiplicative telescopy
$$\rm \frac{a_1}{a_n}\, =\, \frac{a_1}{\color{#C00}{a_2}}\frac{\color{#C00}{a_2}}{\color{#0A0}{a_3}}\frac{\color{#0A0}{a_3}}{\cdots}\cdots\dfrac{\cdots}{\color{brown}{a_{n-1}}}\frac{\color{brown}{a_{n-1}}}{a_n}$$
-
The following is multiple choice question (with options) to answer.
An acquired characteristic is | [
"a permanent welt gotten many years ago",
"freckles from your mom's genes",
"a large nose just like your dad's",
"brown, curly hair that resembles your sister's"
] | A | an organism 's environment affects that organism 's acquired characteristics |
OpenBookQA | OpenBookQA-4180 | optics, visible-light, reflection, refraction, geometric-optics
Title: Image formation at surface of water Consider a lake full of water which has an object immersed in it. Now, if an observer was at the surface at a sufficient distance so that the light ray from the object is internally reflected, would he be able to see the object? If not, then why?
Conversely, would the fish see the observer (since the visibility is constrained to a small area)? Let's draw an image to show the observer above the lake looking at an object in the lake:
where the angles $i$ and $r$ are given by Snell's law. You say:
Now, if an observer was at the surface at a sufficient distance so that the light ray from the object is internally reflected
but there is no position for the observer where they cannot see the fish and likewise the fish can always see the observer. All that happens is that as the distance between the observer and fish increases, so the angle $i \rightarrow \pi/2$, to the observer the fish appears to be nearer and nearer to the surface. This is the well known phenomenon of water appearing to be shallower than it really is.
From the fishes point of view all the light from above the water is compressed into a cone of half angle equal to the critial angle. At values of $r$ greater than the critical angle the fish sees a reflection of the lake bottom.
The following is multiple choice question (with options) to answer.
If a fish lives in water that is very dark, the fish may calibrate its body over time to | [
"absorb helium",
"turn invisible",
"eat more",
"be blind"
] | D | an organism 's environment affects that organism 's acquired characteristics |
OpenBookQA | OpenBookQA-4181 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which relationship is true? | [
"birds have warm blood; snakes have warm blood",
"birds have hot blood; snakes have cold blood",
"snakes and birds have the same type of blood",
"birds have cold blood; snakes have warm blood"
] | B | a bird is warm-blooded |
OpenBookQA | OpenBookQA-4182 | beginner, ruby, api
def display_help
puts 'Iplayer_data helps you keep track of your favourite programs.'
puts 'It can store the programs you want to follow, then display information regarding episodes of those programs.'
puts 'You can (a)dd, (d)elete or (v)iew your favourite programs...'
puts 'Display (e)pisodes, (c)ategories, or (r)egions, or e(x)it.'
puts 'Some instructions require extra input - just put a space after the first letter than type it in.'
puts 'eg to add Top Gear, input "a top gear" (case insensitive)'
#(d)elete, (p)rogrammes
end
require 'pp' # pretty print
ip = Iplayer_data.new
re=''
until re[0] == 'x' do
print '>'
re = gets.chomp
case re[0]
when '?' then display_help
when 'a' then puts ip.add_programme(re[2..-1])
when 'd' then puts ip.delete_programme(re[2..-1])
when 'v' then pp ip
when 'c' then pp ip.categories
when 'r' then pp ip.regions
when 'e' then
#list of episodes, ordered by soonest to latest to expire
ep = ip.get_episodes.sort_by { |episode| episode["versions"][0]["availability"]["end"]}
ep.each do |e|
e["time_left"] = e["versions"][0]["availability"]["remaining"]["text"]
puts e.select {|k,v| ["id", "title", "subtitle", "time_left"].include?(k) }
end
puts "No episodes found" if ep.count==0
when 'x' then puts "Exiting..."
else puts "Sorry, I did not recognize that input. Type \"?\" for help."
end
end My thoughts, in no particular order:
The following is multiple choice question (with options) to answer.
If you want to watch TV it must first have | [
"more Chinese parts",
"a flux capacitor",
"been plugged in",
"a cloudless day"
] | C | an electrical device requires electricity to turn on |
OpenBookQA | OpenBookQA-4183 | wasps
Title: Can wasps see under moonlight? It appears that the best time to attack a wasp nest is in the middle of the night. Their venom might terrorize us (my five-day old sting remains swollen and is starting to have red bumps in an area the size of a tennis ball), but at least our eyesight is superior. If we attack while they are asleep, or at least resting, we have our best chance of escaping unscathed—or so the online pundits claim.
The nest in question is at the edge between the wall and the roof protrusion. Because it is 8 feet off the ground rather than on the ground, it would appear to be a paper wasp nest. But because it is covered with paper and the individual cells are occluded, with the entrance at the bottom the only visible path leading inside, it may well be a yellow jacket nest.
Maybe it's futile to attack the nest in September. One might as well let them be. The nest will anyway be deserted in October when the temperature starts to freeze overnight. But it's never too early to prepare for next Spring.
I could choose a night when there is absolutely no light—not even moonlight—but then I myself would need to use a flashlight, providing them with the means of pursuing me. Or I could choose a full-moon, or near full-moon, night, and then I can see and they can, perhaps, not see.
Can wasps see under moonlight? No.... probably not... wasp cannot see at night... their scotopic vision{dim light vision} is not well develop so before sunset they return back to thier nest... so at night.. probably you can get them all together... rather then hunting for each indivisually...for reference https://sciencing.com/how-to-identify-wasps-bees-13406632.html hope it helps..
The following is multiple choice question (with options) to answer.
Which would you have the most difficult time spotting in the woods? | [
"an adult Brontosaurus",
"a polar bear",
"a large airplane",
"satanic leaf-tailed gecko"
] | D | An example of camouflage is an organism looking like leaves |
OpenBookQA | OpenBookQA-4184 | exoplanet, terrestrial-planets
I don't think that the authors are claiming that this is exactly what all the planets are made of, but simply illustrating that at present there do not seem to be any large deviations from such a composition (for example, planets that are made solely of iron).
There are relatively few planets on this diagram, because it is difficult to obtain the masses of small transiting planets (it requires detection of the doppler shift caused by the pull of the planet on its host star).
Of course different models yield somewhat different results. For instance, Wagner et al. (2012) used the same data for Kepler-10b and CoRoT-7b and their own detailed models to argue that these planets have an iron core that makes up about 60% of the planet - i.e. a lot more than makes up the Earth.
At the moment the data for the lowest mass planets currently indicate that there could only be a limited amount of diversity. But the information that we are working with, the sample size, and the fact that only masses and radii are
determined, is too sparse to be sure.
From a theoretical point of view there are many ideas. The basic concept about the formation of the terrestrial-type planets is that they form (relatively) close in to the parent star and have compositions that are reflective of what elements and minerals can condense out of the protoplanetary disk at high temperatures. This in turn depends on the balance of elements that are present in the protoplanetary disk, where in the disk the planet forms, the detailed structure of the protoplanetary disk, how it cools and how planets migrate in the disk. Unsurprisingly, by varying some of these conditions it is possible to create planets with a wide variety of compositions, which as I said above, appears to be mildly contradicted by the available evidence. At the most basic level we understand why the Earth and other terrestrial planets are comparatively lacking in "volatile" elements like hydrogen and helium (and to some extent C, N, O and noble gases), because they (or minerals containing them) could not condense at the high temperatures close to the proto-Sun.
The following is multiple choice question (with options) to answer.
The outer shell of our planet is made of | [
"sedimentary formations",
"plastic",
"foam",
"cheese"
] | A | Earth 's surface is made of rock |
OpenBookQA | OpenBookQA-4185 | structural-engineering
Title: Rammed Earth Building I am estimating the amount of materials required to make a rammed earth building and I can't find anything related with the foundation of rammed earth building and about two-storeyed rammed earth building. Can you tell me about how the foundations are constructed on rammed earth building and what should be done to make two storeyed rammed earth building? I would suggest the safest way is to build the foundation with reinforced concrete and leave dowels out to bond with the rebars of the rammed earth wall.
In the middle east, they have build adobe houses for centuries by combining clay and straw as a wall material. This system has proved to have excellent thermal properties, but not sufficient strength for earthquakes.
They used to mix lime with sand and silt and clay as primitive concrete for the foundation.
There is no code for the rammed earth construction. So every individual needs to hire an engineer to do the calculations and prepare the plans for them. here are some photos that were taken during the construction.
source
The following is multiple choice question (with options) to answer.
Using what the surface of the Earth is made of, you could build | [
"a tire",
"computer",
"a castle",
"a telephone"
] | C | Earth 's surface is made of rock |
OpenBookQA | OpenBookQA-4186 | temperature, weather, humidity
Title: Why does relative humidity appear limited for temperatures above 80°F? I recently compiled ten years of NOAA local climatological data. I noticed that the maximum relative humidity dropped linearly from 100% at about 80°F to 20% at about 110°F. Nothing obvious comes to mind that explained this observation.
Here is my scatterplot:
Here is graph showing the edge of interest:
I would have expected to see relative humidity values at or near 100%, even for temperatures near 100°F. Obviously, that's not what I see. Maybe this has something to do with a limit of absolute humidity or density?
Nothing obvious comes to mind that explained this observation.
Consider a simple model with the following aspects/assumptions:
The coastal regions of large bodies of water on Earth are at most as hot as about 80°F. (Some exceptions exist, such as the Persian Gulf. If the data are taken from weather stations near areas of human occupancy, such as airports, note also that regions with a wet-bulb temperature much greater than about 80°F are generally hazardous to humans.)
Water enters the atmosphere predominantly through evaporation from these large bodies of water, up to the maximum relative humidity at that maximum temperature. That fixes one point of the line you observed: 100% relative humidity at 80°F (300 K).
The vapor pressure $P_\text{vapor}$ of water increases with increasing temperature $T$; a simple model of this exponential relation is the August equation $P_\text{vapor}\approx\exp\left(20- \frac{5100}{T}\right)$, with $T$ measured in kelvins.
The relative humidity corresponds to the actual partial pressure of water vapor relative to the saturation vapor pressure at that temperature. We characterize this behavior in part through psychrometric charts.
Therefore, we should expect a downward-sloping maximum relative humidity with increasing temperature as the saturated vapor is transported inland to regions over land that may be hotter. The maximum mass of water vapor remains the same, as does the maximum absolute humidity, but the maximum relative humidity drops with increasing temperature.
The following is multiple choice question (with options) to answer.
In which situation would there be the greatest amount of humidity? | [
"in the desert",
"during snowfall",
"before a hurricane",
"on a mountain"
] | C | humidity is the amount of water vapor in the air |
OpenBookQA | OpenBookQA-4187 | mechanical-engineering, structural-engineering, control-engineering
For example, if I wanted to setup such a facility, who would I have to consult?
You either find a consulting engineering firm with a lot of experience in designing and planning (and building!) such a plant. Or you find anexperienced hydroponics expert (the first bullet point) and a consulting firm with experience in a relevant field like wastewater.
Alternativly, you find a company specialized in building and selling hydroponics farms. This will give you less choice over the final plant - the company will want to work with their preferred components and concepts, and crucially they will want to reuse as much egnineering work from previous projects as they can.
The following is multiple choice question (with options) to answer.
Greenhouses are structures used to house plants during | [
"nothing",
"freezing conditions",
"cold beverages",
"space"
] | B | a greenhouse is used to protect plants from the cold |
OpenBookQA | OpenBookQA-4188 | zoology, marine-biology
Title: Why do stranded marine mammals die so quickly? Mammals have lungs, so do marine mammals. Nevertheless some marine mammals seem to die rather quickly when they strand on a beach.
As they have lungs and can breath while on land, why do they die so quickly? Not being in water only restricts them from food.
Do they maybe try to get back into the water so rudely that they get hurt by rocks and/or break bones? Pressure difference doesn't seem to be a problem as they can jump out of the water as well.
I was wondering after reading this article on stranded pilot whales that got spot but died rather quickly after. In the case of whales, I always thought that it was something to do with the fact that they rely upon buoyancy to support their weight and this seems to support that view:
When whales, including small whales or dolphins become stranded on beaches
they suffer from the pressure of their own weight on their organs,in the
water they are weightless. They also suffer from overheating as they have
blubber that insulates them in the water and outside of the water causing
them to overheat. This is why we place wet towels and cold water on their
fins and flukes when do they strand to help keep their body temperature
down. Unfortunately most stranded whales do not survive once they have
beached themselves.
The following is multiple choice question (with options) to answer.
Lungs are to hampsters as ________ are black tipped sharks. | [
"gills",
"hearts",
"stomachs",
"fins"
] | A | gills are used for breathing water by aquatic animals |
OpenBookQA | OpenBookQA-4189 | 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.
Gills are used by what for breathing water? | [
"marlins",
"eagles",
"zebras",
"goats"
] | A | gills are used for breathing water by aquatic animals |
OpenBookQA | OpenBookQA-4190 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
Some of these creatures with fluffy butts live in grassy areas | [
"snakes",
"doe",
"scorpions",
"turtles"
] | B | some hares live in fields |
OpenBookQA | OpenBookQA-4191 | species-identification, entomology
Title: Big Bug from Peru I'd like to have a name for this guy. There were 5 or 6 of them zipping around the flower bed on the coast of Peru about 120 kms south of Lima. That is a hawkmoth, probably Hyles annei (Guerin-Meneville, 1839). It is one of a number of moth species commonly called "hummingbird," "sphinx," or "hawk" moths in the family Sphingidae.
Beautiful, isn't it? :)
edit - sorry, I originally misidentified this as Hyles lineata - the pattern is slightly different.
The following is multiple choice question (with options) to answer.
Where would a hare live? | [
"in the zoo for its safety from sharks",
"a field for sustenance",
"space for its low gravity",
"a desert for its high temperatures"
] | B | some hares live in fields |
OpenBookQA | OpenBookQA-4192 | general-relativity, gravity, black-holes, event-horizon, tidal-effect
And yes, you would still be able to move your body parts normally, including using your hands to turn the pages of the book.
Think of it as a really long bungee jump, but with no bungee to bring you back. Nothing can bring you back. It's a one-way trip, and the friends you left behind will never see you cross the horizon, but otherwise it's just like a bungee jump.
The following is multiple choice question (with options) to answer.
if a person looked a their head in a mirror, and moved toward it, what would happen? | [
"the head would start to grow",
"the head would explode",
"the head would start to shrink",
"the head would disappear"
] | A | a mirror reflects light |
OpenBookQA | OpenBookQA-4193 | jupiter, newtonian-telescope, telescope-lens
Collimation - look this up, it just means adjusting the two mirrors
so your eye is looking right down the tube in a straight line. For a
long focal length scope like yours, it's not likely to be a problem
unless one of them is wildly out of line.
Tube currents/thermal behaviour - on almost any cold night, when
the tube and main mirror are still warm from being indoors, rising
air currents in the tube will mess up your image and make it
shimmery, at high power. Low power will look OK. It might take an hour or so for the image to improve (a guess)
Anyway, in summary my guess is changing the eyepieces straight away won't make a dramatic difference. Eyepiece makers will say otherwise of course :)
The following is multiple choice question (with options) to answer.
A telescope uses what to redirect light | [
"money",
"shiny glass",
"lasers",
"people"
] | B | a mirror reflects light |
OpenBookQA | OpenBookQA-4194 | everyday-chemistry, thermodynamics, surface-chemistry
Why did the cardboard start to curl up as it began to burn?
Why did it retain its texture if not shape and size? The curling up has a simple reason: the burning was not uniform. Paper contains water (really!), and heating it makes it lose the water.
Now, paper is a bad conductor of heat. When you burn it, inevitably the flame will be mainly on one side(the side that's pointing up). The flame will transfer heat to nearby regions of paper, and evaporate some (or possibly all) of the water. The loss of water leads to a contraction of the cellulose fibers in the paper (I'm not too sure of this, comments appreciated). But, this only happens on one side of the paper. Even though paper is razor-thin, the fact that it still has two "faces" is important here. Now, due to the contraction, the paper curls in that direction (similar to how a bimetallic strip works). That's it.
The reason for retaining texture, is something I'm not too sure about. The burning reaction throws up a lot of soot, but a lot of the products stay right where they are. This results in the charred/burnt paper occupying the previous position of the cellulose. While charred paper isn't a polymer and thus isn't too strong, it can "mimic" the initial structure just by occupying the position of the cellulose. But, unlike cellulose, if we try bending it, it will crumble since there are no long polymer "chains"/intermolecular forces holding it together. It's like the difference between a house of cards and a similar "house", made of a single piece of rubber. The structure is the same, but the former case is only staying together because it had the "luck" to exist in a stable configuration. Disturbing it will destroy it.
The following is multiple choice question (with options) to answer.
When the Mountain held the Hound's face to the fire, it caused | [
"joy",
"children",
"beautiful skin",
"scars"
] | D | burning a living thing usually causes harm to that living thing |
OpenBookQA | OpenBookQA-4195 | telescope, optics
Title: Shouldn't this cause a fire? This website shows a telescope projecting the sun onto a blackboard: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun.21/
Why isn't the board catching fire? You can easily start a fire on a sunny day by targeting the focal point of a magnifying glass onto something flammable. Why isn't the telescope in this picture doing the same thing?
Photo by Luis Fernández García It could start a fire if the screen is at the focal point of the optical system. That is how you light fires with a magnifying glass.
Here, the blackboard is likely away from the focal point, so you can see the shape of the eclipse (and you get a bigger image) without setting things on fire.
Although this is fairly safe, there are a few things to pay attention to:
If you do this, make sure nobody can walk between the telescope and the screen, because if they go near the focal point, they could get very hot.
Doing this will cause your telescope to heat up. If there are any plastic parts, they can melt.
The telescope in the picture seems to have a small opening. Don't do this with a big telescope. You don't need to collect a lot of light.
Not an answer to the question, but an important note: Observing the Sun is the most hazardous thing you can do in astronomy. Make sure you know what you are doing before you try.
The following is multiple choice question (with options) to answer.
Fires, although dangerous might help with | [
"magic",
"my feelings",
"cultivation",
"sadness"
] | C | burning a living thing usually causes harm to that living thing |
OpenBookQA | OpenBookQA-4196 | newtonian-mechanics, newtonian-gravity, history, singularities
But in general, it seems Newton wasn't too explicit in some of the subtleties. According to Essays in the History of Mechanics - Clifford Truesdell, it was Euler in his Mechanica that pointed out some of the subtlety.
... while Newton has used the word 'body' vaguely and in at least three different meanings, Euler realized that the statements of Newton are generally correct only when applied to masses concentrated at isolated points; he introduced the precise concept of mass-point and this is the first treatise devoted expressly and exclusively to it.
In particular, the relevant parts seem to be in Volume I, Chapter 2 of Mechanica. Here I try to pull out relevant parts, where he builds up the idea of replacing a body composed of many parts by a single point at its center of mass, and a set of forces of restitution imagined to be infinite elastic forces keeping the various parts of the body joined together.
174 ... it appears possible to determine the motion of a small body, acted on by any kind of forces. ... 175. The force of restitution is that imaginary infinite force, which restores the separate parts of the body again to their previous state. ... 177. ... the restoring force must be considered as provided by an infinite elastic force ... 182. Therefore although the force of restitution is imaginary and only exists in the form of thoughts, yet the effect of this follows the real laws of motion. ... 184. ... that bodies separated into any number of parts can be brought together at the common centre of gravity.
So, not to put words in the mouths of the likes of Newton and Euler, but it would appear as though the talk of point masses going as far back as the beginning is much in line with the quote of Landau's I opened with. It was considered a useful simplification of problems where the extent of the body was small compared to its motion more generally. For gravity in particular, Newton (and Euler) spent great efforts demonstrating that for an extended body, one could replace its individual pieces with a point at the centre of mass, without affecting the analysis. And while at the time there was not a precise theory of any forces that could be keeping those bodies together, preventing their collapse under gravity alone, they had no difficulty imagining those forces as infinite elastic forces between the individual pieces.
The following is multiple choice question (with options) to answer.
In a system of a body, this thing is broken down into smaller pieces to be effectively used: | [
"wax",
"nutriment",
"stones",
"glass"
] | B | the breaking down of food into simple substances occurs in the digestive system |
OpenBookQA | OpenBookQA-4197 | human-biology, circadian-rhythms, digestive-system
Title: What influences the timing of human bowel movements in the morning? I'm trying to understand if the timing of human bowel movements in the morning is associated with the circadian rhythm, and can thus be used to make predictions about the circadian rhythm.
What influences the timing of bowel movements? Is it the timing of meals, caffeine intake or is it a biologically programmed time?
Thank you! The bowel movements are influenced by a lot of factors. For example, when you eat a meal it induces a movement in your large intestines, to defecate and clear up space for new food.
Also, there is MMC, migrating motor complex, which is responsible for the bowel movements when you are fasting. It causes a flushing effect, which prevents bacteria to overproduce in intestines.
So, the daily bowel movements are mainly influenced by the timing and content of the food that you eat. But as I said there are many other factors. The gastrointestinal system has a very complex nervous system. Even psychological factors can effect the bowel movements greatly, for example extreme physical pain may induce the symphatetic system and cause constipation.
Also caffeine may affect it, like many drugs do.
The following is multiple choice question (with options) to answer.
Which likely occurs in the digestive system? | [
"twinkies are converted to usable material",
"air comes in and out",
"twinkies are baked fresh",
"plastic is found here"
] | A | the breaking down of food into simple substances occurs in the digestive system |
OpenBookQA | OpenBookQA-4198 | evolution, species
Title: Parents that eat their own children I am told that there are some species, like fish or rabbits, that if let, will eat their own children. If this is true, how does a species like this exist? Shouldn't the fact that they kill their own lineage make them nonviable? Yes, it is true.
Prairie dogs
Prairie dogs for example are known for frequent infanticides.
Many other species kill their babies too
But of course, such behaviour also exists in other lineages such as grey langurs, gerbilles, lions, giant water bugs and Bottlenose dolphins (just to cite a few examples).
How does that evolve
It will be impossible to provide a complete universal explanation to this behaviour because the evolutionary processes causing this behaviour varies from lineage to lineage. For examples, in lions, only males kill young of the females that are still nursing and they do so when taking over a new harem only. In prairie dogs, mothers cause infanticide preferentially on others' babies but also on their own babies.
Going into the details of how such behaviour evolves in every specific lineage would probably require writing an intro on kin selection and other fields of evolutionary biology which is way too much for a single post. You may want to have a look at the wikipedia article infanticide for a start.
Shouldn't the fact that they kill their own lineage make them nonviable?
Of course, they don't kill all the babies. Only a fraction of them!
The following is multiple choice question (with options) to answer.
A creature that is incapable of giving birth to offspring that are living as they exit is the | [
"bear",
"human",
"beaver",
"salamander"
] | D | mammals give birth to live young |
OpenBookQA | OpenBookQA-4199 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
What gives birth to live young? | [
"tarantulas",
"wildcats",
"vultures",
"anacondas"
] | B | mammals give birth to live young |
OpenBookQA | OpenBookQA-4200 | thermodynamics, electricity, dissipation, thermoelectricity
Title: Can a Peltier/Seebeck cell transfer energy from a "thermally insulated" system converting (a part of) thermal energy into electrical energy? Suppose you have a closed system, as per the schema attached below, which walls are thermally insulated.
Suppose you want to reduce the temperature of the fluid inside the closed system, without dissipating 100% of the fluid thermal energy into the environment.
Can a Seebeck cell convert (a part of) the thermal energy of the fluid into electrical energy?
Is the Seebeck cell able to convert a part of the thermal energy into electrical energy (with a given efficiency), or the generation of electrical energy is only a cause of the temperature gradient and this thermal energy will eventually entirely return to the environment thorugh the cell (which, differently from the walls of the system, is clearly not insulated)?
Say, we have a stick of some fitting material. It has some temperature, so all electrons in the material bounce around wildly. Some randomly bounce leftwards; others randomly bounce rightwards. There is no net flow of electrons in any direction. There is no current.
Now, heat up one end. Those now hotter electrons will now bounce around even more wildly. This will make them "fill more space" (more wild random motion means much more pushing on the surrounding particles).
When the electrons "fill more" in one end, there is less "space" there. They start drifting towards the other and still more "spacious" end.
Drifting electrons is a current; electrical energy. This is the essence of the thermoelectric Seebeck effect.
The energy that caused them to move more wildly is directly the thermal energy absorbed at the hot end. They still carry this thermal energy, now in the form of a higher amount of kinetic energy at the micro-scale. So, yes, the Seebeck effect converts thermal energy into electric energy so that there is less thermal energy present - although we are talking about tiny, tiny amounts depending on your situation.
The following is multiple choice question (with options) to answer.
thermal energy insulators are often good electrical insulators like: | [
"metallic rocks on the ground",
"fan on the ceiling",
"the rubber sandwiched between two iron slabs",
"metal knives for sale"
] | C | wood is an electrical energy insulator |
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