source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2301 | 5,224 views
In a certain town, the probability that it will rain in the afternoon is known to be $0.6$. Moreover, meteorological data indicates that if the temperature at noon is less than or equal to $25°C$, the probability that it will rain in the afternoon is $0.4$. The temperature at noon is equally likely to be above $25°C$, or at/below $25°C$. What is the probability that it will rain in the afternoon on a day when the temperature at noon is above $25°C$?
1. $0.4$
2. $0.6$
3. $0.8$
4. $0.9$
Answer is C) $0.8$
$P$(rain in afternoon) $= 0.5\times P($rain when temp $\leq 25) + 0.5 \times P($ rain when temp $> 25 )$
$0.6 = 0.5\times 0.4 + 0.5\times P($ rain when temp $> 25 )$
so,
$P$( rain when temp $> 25$ ) $= 0.8$
This is a question of Total Probability where after happening on one event E1, the probability of another event E2 happening or not happening is added together to get the probability of happening of Event E2.
Given P(Rain in noon) =0.6 (This is total probability given).
"The temperature at noon is equally likely to be above 25°C, or at/below 25°C."
means P(Temp less than or 25) = P(Temp >25) =0.5
P(Rain in noon) = P(Temp $\leq$ 25) * P(Rain | Temp $\leq$ 25) + P(Temp $>$ 25) * P(Rain| Temp $>$ 25)
0.6= (0.5*0.4) + (0.5*X)
X=0.8 Ans (C)
The following is multiple choice question (with options) to answer.
A person in precipitating weather will want to | [
"be electrocuted",
"be vanquished",
"be drowned",
"be safeguarded"
] | D | shelter can protect humans from weather |
OpenBookQA | OpenBookQA-2302 | python, python-3.x
for anhang_ in anhang:
with suppress(EmptyDict):
for record in Anhang.from_dict(
anhang_, immobilie=self):
yield (record, PatchMode.CREATE)
else:
self.logger.debug('anhaenge or anhaenge.anhang is unchanged')
If you can't adapt either of the above, then I'd say your code is good for your situation.
The following is multiple choice question (with options) to answer.
A huckleberry patch will only grow if it receives | [
"nutriment",
"grass",
"frost",
"sand"
] | A | an plant requires food for survival |
OpenBookQA | OpenBookQA-2303 | electrostatics, electric-fields, charge
$$
So it wouldn't be a solution to the "real problem" you're trying to solve.
You could, however, interpret it to be a solution to a different problem, one in which there are no charges present ($\rho = 0$) in the volume of interest. In other words, it's not entirely unphysical, it's just the solution to a different physical situation than the original one.
The following is multiple choice question (with options) to answer.
A solution could be | [
"pebbles and soil",
"peas and corn",
"juice and vodka",
"toothpaste and bristles"
] | C | a solution is made of one substance dissolved in another substance |
OpenBookQA | OpenBookQA-2304 | c#, object-oriented, snake-game
if (choice2.Checked)
{
if (Player1setting.Gameover == false)
{
Brush SnakeBoddyColor;
for (int i = 0; i < SnakeBoddy.Count; i++)
{
if (i == 0)
{
SnakeBoddyColor = Brushes.Black;
canvas.FillRectangle(SnakeBoddyColor,
new Rectangle(
SnakeBoddy[i].X * Player1setting.Width,
SnakeBoddy[i].Y * Player1setting.Width,
Player1setting.Width, Player1setting.Height
));
}
else
{
SnakeBoddyColor = Brushes.Red;
canvas.FillRectangle(SnakeBoddyColor,
new Rectangle(
SnakeBoddy[i].X * Player1setting.Width,
SnakeBoddy[i].Y * Player1setting.Width,
Player1setting.Width, Player1setting.Height
));
}
}
}
}
if (choice1.Checked)
{
if (Player2setting.Gameover2 == false)
{
Brush SnakeBoddyColor2;
for (int x = 0; x < SnakeBoddy2.Count; x++)
{
if (x == 0)
{
SnakeBoddyColor2 = Brushes.Black;
canvas.FillRectangle(SnakeBoddyColor2,
new Rectangle(
SnakeBoddy2[x].X * Player2setting.Width2,
SnakeBoddy2[x].Y * Player2setting.Width2,
Player2setting.Width2, Player2setting.Height2
));
}
else
{
SnakeBoddyColor2 = Brushes.Blue;
canvas.FillRectangle(SnakeBoddyColor2,
new Rectangle(
SnakeBoddy2[x].X * Player2setting.Width2,
SnakeBoddy2[x].Y * Player2setting.Width2,
Player2setting.Width2, Player2setting.Height2
));
}
}
}
}
The following is multiple choice question (with options) to answer.
A painted turtle will have natural coloring, but a turtle that has been painted will have | [
"cold colors",
"thirty colors",
"artificial colors",
"natural colors"
] | C | painting an object a color causes that object to be that color |
OpenBookQA | OpenBookQA-2305 | atmosphere, climate-change, thermodynamics, radiative-transfer
All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.
Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: Dubai construction alters local climate
Additional references
Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution
of global anthropogenic heat flux. Atmos. Oceanic
Sci. Lett., 5, 108–112.
The following is multiple choice question (with options) to answer.
What activity changes the local environment the most? | [
"people sometimes camping",
"moderate rain",
"over-logging",
"rabbit breeding"
] | C | humans changing an environment sometimes causes that environment to be destroyed |
OpenBookQA | OpenBookQA-2306 | dna, dna-sequencing, genomes, human-genome, mouse
I hope this is understandable, if you need any clarification on terms, please ask :)
The following is multiple choice question (with options) to answer.
A family moves into an old home that mice have moved into. Soon after the human family moves in, the family of mice are likely to | [
"be frozen",
"be ejected",
"be happy",
"be welcomed"
] | B | humans moving into an environment usually causes native species to lose their habitats |
OpenBookQA | OpenBookQA-2307 | zoology, entomology, ant, sociality
Giving some reasons for their existence:
To what use is all this effort? Not, it seems, as protection from the elements. The earthworks fall apart in rain, and disintegrate when the earth is dry. Arcades are thin enough to puncture with a tap of a finger, which means a route is weatherproof only when it travels through an underground tunnel, perhaps dug and then abandoned by other animals. Alternatively, near the nest the ants may make a subterranean route of their own: over time, construction crews can scratch away so much soil from the trail surface that the highway sinks from view, at which point the ants seem to be able to construct a thicker, rainproof cover that becomes flush with the surrounding land.
The main function of this relentless building is defense. Because trunk trails extend for dozen of meters, they travel through territory controlled by other ant species. Marauder ants must therefore be organized to protect the trunk trails from aggressive neighbors or even from hapless passerby such as the Diacamma.(...)
...after an arcade has been completed[,] the Diacamma workers could now walk over the trunk trail, blissfully ignorant of the industry below them. if a trail should sink underground, it is as protected as a passage in an army bunker, safe even from human footfalls.
Bulwarks constructed over trails and provisions prevent battles among competing marauder ant colonies as well. Where they are absent, combat can last a day and engage thousands of minor workers, which pour along the line of contact between the armies.
The following is multiple choice question (with options) to answer.
A protected environment will probably be | [
"on fire",
"fenced",
"illegal",
"underground"
] | B | An example of protecting the environment is creating protected areas |
OpenBookQA | OpenBookQA-2308 | javascript, array, tree
var goal = paths.reduce(function(carry, pathEntry){
// On every path entry, resolve using the base object
resolvePath(carry, pathEntry.path);
// Return the base object for suceeding paths, or for our final value
return carry;
// Create our base object
}, createPath());
document.write(JSON.stringify(goal));
The following is multiple choice question (with options) to answer.
A person has a clean yard at the beginning of a season. As the seasons go on and the trees in the yard grow, | [
"more trees are indoors",
"the yard needs to be raked more",
"some trees are inside",
"fewer leaves are in the yard"
] | B | when a plant grows , the number of the leaves of that plant may increase |
OpenBookQA | OpenBookQA-2309 | 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.
Comparing an arid acre to a jungle acre, the jungle acre will host | [
"less moisture",
"excesses of moisture",
"fewer water droplets",
"less fluid"
] | B | as dryness increases in an environment , the available water in that environment will decrease |
OpenBookQA | OpenBookQA-2310 | temperature, light, heat
Title: Why does sunburn cause fever? Today I found out that sunburns can cause fever.
What I don't understand is how/why? In my understanding fever is the side effect of an immune reaction against an intruder, mainly bacteria (though I admit I can be wrong).
Google searches like "can sunburn cause fever" only bring up that it is possible, but not why. Here is a good article on the topic.
https://www.nlm.nih.gov/medlineplus/ency/article/003227.htm
But it's most likely due to the fact that a sun burn is an actual burn on the skin that can cause inflammation, inflammation can in turn cause fever. Also having a really bad sunburn can open you up more to the possibilities of skin infections. If this happens then once again you might get a fever due to infection. If you really want to find out more on the cause of fever after sunburn you need to examine the pathophysiology of fever and why fever happens. I bet my money on fever due to skin inflammation after a sunburn, I guess the real question would be why does inflammation cause fever since sunburn = skin inflammation
Here is a good article
http://antranik.org/inflammation-and-the-pathophysiology-of-fever/
The following is multiple choice question (with options) to answer.
Which of the following burns due to wax? | [
"electric kettle",
"internal combustion engine",
"tea candle",
"gas stove"
] | C | lighting a candle causes that candle to burn |
OpenBookQA | OpenBookQA-2311 | human-biology, physiology, proteins, amino-acids, diet
Title: Amino Acid requirement + intake in relation to diet + meat type I was arguing with a friend:
I said: The Yulin festivals cannot be condemned by western culture, as we also kill animals in equally cruel ways.
She said: It isn't just that the killing is cruel, but it doesn't help us, as humans do not derive the same essential amino acids from consuming these less traditional meats (e.g. dogs, cats, etc) like they would from consuming more traditional meats (e.g. cow, pig, goat, etc) She cites her father, a geneticist, as her source.
Question one:
Are my friend and her father correct? Does the consumption of a less traditional meat (e.g. cats, dogs, etc) provide fewer essential amino acids than the consumption of traditional meats (e.g. cows, pigs, chickens, etc)?
Question two:
My friend also made a comment about veganism and vegetarianism (I am a vegetarian), stating that for the same reason as her and her father's above comment, people who exclude meat from their diet need to use supplements. Is this correct, or would it also be possible to just vary diet to obtain these essential amino acids? There is a difference between animals in their requirements for amino acids. For example, cats need high amounts of taurine (and can't make it) and when fed diets lacking enough can go blind. This is why vegans trying to feed vegan diets to their pets can be very bad for the pet. Animal proteins have sufficient taurine for the cat.
However, the meat of a cat or dog is just as a complete source of protein for humans as any other meat. All essential amino acids are there in sufficient ratios. Suggesting otherwise by her father suggests some confusion between the dietary needs of cat vs. the nutritional value of the cat to another predator.
Your second question is easily answered by looking up essential amino acids. Wiki is plenty sufficient to get the gist Wiki Link. In short, most plants don't contain the full complement of amino acids that humans require (and can't make on their own). So to get this full complement, it requires eating multiple plant products that together contain the required amino acids.
From Harvard School of Public Health
The following is multiple choice question (with options) to answer.
Which is a carnivore? | [
"a cow",
"a caterpillar",
"a vegan",
"a shark"
] | D | carnivores only eat animals |
OpenBookQA | OpenBookQA-2312 | population-genetics
Title: Average and lowest degrees of kinship/consanguinity among humans? I would appreciate insight into the average, median, RMS or any similar measure of relatedness among the current world population - and perhaps something about how rapidly this may be changing. A similar question is how un-related any two humans can be: i.e., what is the lowest degree of consanguinity between the two most distantly related people. The context is an exploration of how humans have evolved tendencies toward racism and other in/outgroup distinctions, when all humans share such a large fraction of DNA with each other, very nearly as much with non-human primates, and about half even with fruit flies. Might be some helpful lessons in there!
Apologies if the question is ill-formed, or answer readily available someplace - I've browsed the Web for several years on this topic, and found nothing I could understand..
Accessible material about most recent common ancestor and identical ancestor point seems to indicate a wide range of both methodologies and results, based mainly on statistical simulations since "hard" genetic structures apparently do not persist. MRCA datings based on mitochondrial and other genetics seem to line up with human behavioral modernity, ca. 200 kya. But there seem to be extreme estimates as recent as 2.3 kya, which implies a lot of mobility and high fertility by some not-so-distant forebears (like Genghis Khan). In any case, IAP may be a better starting point for this shared-anncestry question.
I'm guessing that no human is further than about a 10th~12th cousin to any other. Can't be more that 32nd, since 2^33 is more than the number of living humans!
All thoughts, including guesses more informed than mine, will be appreciated.
~ ~ ~ ~ ~
Addendum - tried to post this as an answer, but it was deleted:
MANY thanks to Zo-Bro-23 for the time, effort and creativity to create his response. I hope it is well-indexed for future explorers to find!
In case useful or interesting to anyone,or sparks further contributions, here were/are my main motivations for this inquiry:
The following is multiple choice question (with options) to answer.
Which of the following would be least likely to reproduce? | [
"2 protozoa",
"2 oak trees",
"2 female cats",
"2 bacteria"
] | C | two females can not usually reproduce with each other |
OpenBookQA | OpenBookQA-2313 | botany, dendrology
Some resources:
http://extension.wsu.edu/maritimefruit/Pages/PruningBasics.aspx
http://puyallup.wsu.edu/~linda%20chalker-scott/horticultural%20myths_files/Myths/Wound%20sealer.pdf
The following is multiple choice question (with options) to answer.
Which is the most dangerous to trees? | [
"sunlight",
"javascript",
"oxygen",
"industrial saws"
] | D | timber companies cut down trees |
OpenBookQA | OpenBookQA-2314 | algorithms, reference-request, distributed-systems
In this problem the events have a total order relation: If you have two events you always can say which one is the oldest of them.
Now, the events don't necessarily show up in the stream in the correct order according to its timestamp. Each event is unique to its timestamp, so there are no two or more events with the same timestamp for the same object. Also, the timestamps don't necessarily form a sequence that always increase by one: if we see e1 with timestamp 1 and e3 with timestamp 3, it doesn't imply the existence of e2 with timestamp 2.
There is no guarantee that all events will be received or when they will be received. It's part of the problem that we only know about the existence of the events that we see in the stream.
The real scenario is even worse: there are multiple computers parallelly processing this stream of events. However, for simplicity, I'll go further in this example considering only one computer.
If the events arrive and are processed in the order described above, then the notifications sent should be:
P(A) = true when e1 arrives
P(A) = false when e3 arrives
P(A) = true when e5 arrives.
That is the correct sequence of notifications because it respects the timestamp order.
Now, imagine that the computer receives the events in the following order:
e1, e5, e2, e4, e3
A naive algorithm which doesn't consider the event's timestamp would send an incorrect sequence of notifications:
P(A) = true when e1 arrives
P(A) = false when e4 arrives
The following is multiple choice question (with options) to answer.
Funerals are common occurrences after | [
"a routine doctor's appointment",
"a person has ceased taking in oxygen and pumping blood thru their system",
"a person is declared in remission from cancer",
"a person has had a big lunch"
] | B | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-2315 | botany, color
Hypothesis 1
It should be remembered that chlorophyll is far from being the only pigment found in leaves. For example, carotenoids - which give yellow and reddish colors - are present in plant leaves. There are many carotenoids (according to Wikipedia there are over 1100 known, but that number will continue to grow). The biological roles of these carotenoids are also varied. In the course of the question, we may be interested, for example, in the photoprotective role of carotenoids. They are involved in the deactivation of reactive oxygen species (ROS). ROS can be formed during photosynthesis and can potentially be harmful to cells. Therefore, in conditions of excess solar radiation, plants can increase concentrations of carotenoids to prevent oxidative stress. It has already been pointed out to you in the comments that younger leaves look yellow - this is a common occurrence. The leaf is a very expensive organ, in the sense that the plant invests a lot of plastic substances in its development. So it makes sense that young, growing leaves get extra protection. That is, a young leaf that has not yet formed all the necessary structures (thick enough cuticle, efficient conductive system, etc.) is less efficient in terms of photosynthesis and therefore more susceptible to negative processes of photodamage. Increased concentrations of carotenoids, among other things, can reduce such risks. If you add to this the small thickness, it is understandable why young leaves often look more yellow.
Hypothesis 2
I have already said that leaves are expensive organs. They have a high protein content, which is very valuable to the plant. If a leaf is damaged or aged, there is a threat of irreversible loss of protein, which would be a great waste. Therefore, in such cases, plants trigger complex processes of removing valuable substances from the leaves. In particular, chlorophyll begins to break down, and the decomposition products are transported to the more durable parts of the plant. This is the reason why leaves change color in the fall, before defoliation. When the concentration of chlorophyll decreases, other pigments, such as carotenoids, increasingly affect leaf color. That's why damaged and old leaves often turn yellowish.
Although, I doubt that in the case of your plant, this process is often the cause for yellow leaves.
Hypothesis 3
The following is multiple choice question (with options) to answer.
Something that is beneficial to plants, especially garden plants, can be formed | [
"in dog bowls",
"in swamp waters",
"in living rooms",
"in microwaves"
] | B | the formation of peat occurs at the bottom of swamps |
OpenBookQA | OpenBookQA-2316 | newtonian-mechanics, rotational-dynamics, air
Title: Direction of rotation of a celing fan From Constellation Energy
Quick energy efficiency tip: To stay cool and manage your energy at
the same time, use ceiling fans to create a “wind chill” in rooms you
are using. The wind chill will help you feel cooler than the actual
temperature. Make sure the ceiling fan is set to turn in a
counter-clockwise rotation.
I was wondering why the ceiling fan is set to turn in a counter-clockwise rotation, instead of the other way around?
Thanks! The blades of a ceiling fan are pitched out of plane slightly. As a result, when the fan spins, the blades push air either up towards the ceiling or down towards the floor. Which direction it pushes air is determined by the direction the fan is spinning, and the direction the blades are pitched. The usual convention is given by the right hand rule: if you hold your right hand so that you can curl your fingers in the direction the fan is spinning, then it will push air in the direction that your thumb is pointing.1 When it's pushing air down on you, it will then be spinning in a counter clockwise direction as you look up at it. You can make it follow a left hand rule by reversing the pitch of the blades.
Once you have set the direction of the pitch of the blades, you can reverse the airflow by reversing the direction the fan spins. Many (most?) modern ceiling fans provide some mechanism to do this. The fans in my house have a small black switch that slides up and down. @Ignacio Vazquez-Abreams mentions using a pull chain in a comment to another answer.
In warm weather, you set the fan so that it pushes air down towards the floor. This causes you to feel a breeze, which cools you. In cold weather, you set the fan so that it pushes air up into the ceiling. You don't feel a breeze,2 but it circulates warm air from the ceiling towards the walls and down towards the floor.
The following is multiple choice question (with options) to answer.
Alice flipped a switch and the ceiling fan started running because | [
"the electricity was cut off",
"a circuit was opened",
"a fuse was blown",
"a circuit was closed"
] | D | completing a circuit causes electric current to flow through that circuit |
OpenBookQA | OpenBookQA-2317 | photons, vision
Title: Dark room lights When I lay down in my room at night it's pretty much completely dark but I observe this strange phenomenon going on.
When I lay down and look at my ceiling I can see my white fluorescent white bulbs and white fan blades but when it's dark I can't. But, as soon as I avert my eyes from the fan and lightbulbs about 1 foot I can see them in the dark but why? If it helps there is a very slight illumination from the street lights. And, also I can't see anything not white on the ceiling.
Why can I see the objects only when I avert my eyes? This is really a biology topic, rather than a physics one.
The light sensing cells in your eyes come in two (or four depending on how you count) types. The cones are color sensitive. The rods are sensitive over almost the whole visible spectrum and offer no color discrimination, but they are considerably more sensitive than the cones.
The rods and cones are not evenly distributed in the eye. Cones are concentrated in the central part of the retina and rods are more common in your peripheral visual region. Which makes your peripheral vision more sensitive to very dim sources than your central vision.
In fact, naked-eye star-gazers learn to look near-but-not-at very dim observing target exactly to take advantage of this effect. But it take a lot of will-power to do at first. You'll find your self having a "Ah-ha!" reaction and then looking right at the target every time you make the trick work. At which point you have to go around again.
The following is multiple choice question (with options) to answer.
Retinas can have light fall on them when | [
"pupils are open",
"rooms are dark",
"eyes are closed",
"lights are off"
] | A | when light enters the eye through the pupil , that light falls on the retina |
OpenBookQA | OpenBookQA-2318 | If you want to model the number of items which are bought, your sample space could be the set of all tuples $(n_{\mathrm{shirt}},n_{\mathrm{suit}},n_{\mathrm{tie}})$, where the $n$'s are the number of each item bought (each one either $0$ or $1$ if we don't buy more than one of each). Then, for example, the event $$\{\text{buying 1 thing}\} = \{(1,0,0), (0,1,0), (0,0,1)\},$$ and the event $$\{\text{buying 2 things}\} = \{(1,1,0),(1,0,1),(0,1,1)\}.$$
The following is multiple choice question (with options) to answer.
A person makes dresses and everyone in a location buys them. Once everyone has bought a dress, the dress sales | [
"boom",
"grow",
"cease",
"increase"
] | C | as the sale of a product decreases , the amount of money made by the person selling that product will decrease |
OpenBookQA | OpenBookQA-2319 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
A frog is moved from a lake to a pond, so it is likely to | [
"adapt",
"melt",
"drown",
"sink"
] | A | living in an environment causes an organism to adapt to that environment |
OpenBookQA | OpenBookQA-2320 | atmospheric-science, meteorology
Title: Why would El Niño affect atmospheric CO2 measurements? Starting with this article in Gizmodo:
El Niño Has Pushed Our Planet Past a Major Climate Milestone and then to this commentary in Nature Climate Change El Niño and a record CO2 rise there seems to be some connection.
I'm pretty sure that El Niño does not directly produce CO2! Can someone help me understand the discussion of the relationship from a physics perspective? Did El Niño affect the measured values of atmospheric CO2? Did it result in CO2 redistribution, or aid CO2 production in some way? My understanding is that El Niño is an unusual change in temperature distribution and wind direction.
I'm not looking for individual opinions or theories, I'd like an explanation of the concepts presented in those two links, from a physics perspective. Thanks!
Images from NOAA via the Gizmodo article: As the author of the Gizmondo article you cited explains,
[...] scientists believe that emissions spiked due to a combination of warming and drying in the tropics, which can accelerate soil carbon decomposition, and large, drought-fueled fires.
Here you can find an equivalent explanation:
The atmospheric carbon dioxide concentration is rising year-on-year due to human emissions, but this year it is getting an extra boost due to the recent El Niño event - changes in the sea-surface temperature of the tropical Pacific Ocean. This warms and dries tropical ecosystems, reducing their uptake of carbon, and exacerbating forest fires. Since human emissions are now 25 per cent greater than in the last big El Niño in 1997/98, this all adds up to a record CO2 rise this year.
Here they give the same explanation and also explain how the influence of El Niño on the increase in CO$_2$ concentration was predicted using numerical models:
The following is multiple choice question (with options) to answer.
Which activity would most increase atmospheric CO2? | [
"gardening",
"walking",
"speedboat driving",
"planting trees"
] | C | carbon dioxide concentrations in the air have increased over the last decade dramatically |
OpenBookQA | OpenBookQA-2321 | genetics, homework, human-genetics
However I really feel like I'm wrong about these assumptions since the math really doesn't add up. The likelihood that so many carriers for a relatively rare disorder all coming together and the fact that 3 of the 4 offspring of the grandparents died with only a 25% chance all seems improbable.
It could be that John's son doesn't have the disorder and what he has is something completely different. What do the geneticists say? This is a very rough draft about the case, not verified, and should not be used for any medical conditions. Ask your own doctor. It is just for demonstrating some Mathematics and genetic passing generally.
Condition: Muscular atrophy
Differential conditions: TODO
Support: history of genetic passing in -1 and -3 generations
Disease
Muscular atrophy as a condition jumps over a generation. The environment/living of your greatgreatgrandfathers determine your grandfathers future, as a rough estimate.
The disease's common feature is recessive autosomality.
Assumptions
Autosomal recessive disease because everyone who exhibits symptoms is not be able to reproduce due to their early death.
TODO genetic passing
What is the genetic profile? Is there any other autosomal recessive diseases in the gene map?
Proposed probabilities where the random variables $X = disease$ and $Y = carrier$ such that the subscript 0, -1, -2 and -3 is about new children's, John's, parents' and grandparents' status, respectively.
Both of John's grandparents must have been carriers
\begin{equation}
P(Y_{-3}) = 100\%
\end{equation}
The probability of John's dad and any aunts and uncles having the disorder is (TODO think this again with the correct genetic passing)
\begin{equation}
P(X_{-2}) = 25\%
\end{equation}
The probability of being a carrier is for dad, aunts and uncles (TODO think this gain with the appropriate genetic passing)
\begin{equation}
P(Y_{-1}) = 50\%
\end{equation}
Disease as a process
$X \sim P_{i}(\mu, \sigma)$, $i = -3, -1, 1, ...$ where I propose the mean $\mu$ and the variance $\sigma^2$.
The following is multiple choice question (with options) to answer.
What would be passed down from parents to their children? | [
"hobbies enjoyed",
"head size",
"number of friends",
"sports played"
] | B | offspring receive genes from their parents through DNA |
OpenBookQA | OpenBookQA-2322 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
A stump is in the outdoors and when the sun comes up | [
"it blows up",
"it is shrunken",
"it grows larger",
"it receives energy"
] | D | if something is outside during the day then that something will receive sunlight |
OpenBookQA | OpenBookQA-2323 | friction, statics
Title: Why is skidding considered kinetic friction when braking on a car? So according to my textbook applying the brakes hardly to essentially lock up the wheels causes skidding which is kinetic friction so the breaking distance is longer. However, if the brakes were "pumped" the card would not skid and it will be considered static friction so the braking distance is shorter. I UNDERSTAND that the coefficient of static friction has a greater magnitude than kinetic friction, so it makes sense as to why static has a greater deceleration and shorter brake distance. HOWEVER, I do not understand why skidding is considered kinetic friction and not static friction; and why "pumping" the brakes causes static friction. Can someone please explain to how they are so? Kinetic friction is all about trying to stop one surface from skidding against another surface. When you have two things such as the wheel and the ground sliding against each other, this is kinetic friction. However, when the wheels are rotating, there is static friction between the ground and the wheel. This is because the wheel is rolling and not sliding against the ground. A point on the wheel only contacts the ground for a very very small instant per revolution, so this is static because there isn't sliding between the ground and the wheel.
The following is multiple choice question (with options) to answer.
Skidding causes friction, as seen in | [
"running a track",
"rolling a car",
"Nascar races",
"riding a bike"
] | C | as the smoothness of something increases , the friction of that something will decrease when its surface moves against another surface |
OpenBookQA | OpenBookQA-2324 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
If a wolf wants to grow big and strong, what must he have? | [
"a car to drive",
"a house to live in",
"a bus to sell",
"good eyes to see with"
] | D | hunting requires seeing prey |
OpenBookQA | OpenBookQA-2325 | ai-design, autonomous-vehicles
Title: Do self-driving cars resort to randomness to make decisions? I recently heard someone make a statement that when you're designing a self-driving car, you're not building a car but really a computerized driver, so you're trying to model a human mind -- at least the part of the human mind that can drive.
Since humans are unpredictable, or rather since their actions depend on so many factors some of which are going to remain unexplained for a long time, how would a self-driving car reflect that, if they do?
A dose of unpredictability could have its uses. If, say, two self-driving cars are in a stuck in a right of way deadlock, it could be good to inject some randomness instead of maybe seeing the same action applied at the same time if the cars run the same system.
But, on the other hand, we know that non-deterministic isn't friends with software development, especially in testing. How would engineers be able to control it and reason about it? Driving Priorities
When considering the kind of modeling needed to create reliable and safe autonomous vehicles, the following driving safety and efficacy criteria should be considered, listed in priority with the most important first.
The safety of those inside the vehicle and outside the vehicle
Reduction of wear on passengers
The safety of property
The arrival at the given destination
Reduction of wear on the vehicle
Thrift in fuel resources
Fairness to other vehicles
The thrift in time
These are ordered in a way that makes civic and global sense, but they are not the priorities exhibited by human drivers.
Copy Humans or Reevaluate and Design from Scratch?
Whoever said that the goal of autonomous car design is to model the portions of a human mind that can drive should not be designing autonomous cars for actual manufacture. It is well known that most humans, although they may have heard of the following safety tips, cannot bring them into consciousness with sufficient speed to benefit from them in actual driving arrangements.
The following is multiple choice question (with options) to answer.
A person wanting to avoid polluting the air will, when considering vehicles, choose | [
"a four-wheeler",
"a truck",
"a convertible",
"a tricycle"
] | D | many vehicles emit pollution into the air |
OpenBookQA | OpenBookQA-2326 | orbit
Title: Does anyone know why three of Jupiter's largest moons orbit in 1:2:4 resonance? Three of the first four moons ever discovered outside of our own planetary sphere of gravitational influence orbit in very close to perfect resonance. Europa's orbit is almost exactly twice as long as Io's, and Ganymede's is almost exactly twice as long as Europa's. Perhaps it is just coincidence. If you look at enough random things, you start to see patterns that aren't necessarily there. But it would be a pretty big coincidence. When I see something like this in nature, I have to wonder if there is an underlying cause.
The ratios aren't quite exactly 2, so if there is a gravitational influence or something that pulls them into this resonance, the influence must not be overpowering enough to force exact resonance. Or maybe it is, given enough time, but "recent" collisions or the pull of other satellites in the system may have driven them a little bit off of their resonance. Has anyone studied this and found a probable reason for this phenomenon? When the Galilean moons formed, they weren't in resonance with each other. All of them were in slightly smaller orbits than they are now. Over time after their formation, Io's orbit slowly moved outward due to tides from Jupiter. This is the same effect that is causing our moon to slowly move away from the Earth (at about the same rate your fingernails grow). It goes like this. The Moon's gravity causes tides to form in Earth's oceans. This bulge of water gets carried forward with Earth's rotation, because the Earth is spinning faster than the Moon is orbiting. Because the moon is still attracting the bulge, it causes a drag on the Earth, slowing its spin. At the same time, the bulge is attracting the moon, causing it to go faster in its orbit. As the moon speeds up, its orbit gets bigger. So essentially, the Earth's spin energy is getting transferred into the Moon's orbital energy. The same thing happens with Jupiter and Io, with a bulge in Jupiter's atmosphere causing Io's orbit to get bigger.
The following is multiple choice question (with options) to answer.
Jupiter's larger mass and orbit contribute to the formation of this area of debris: | [
"Inner Solar System",
"Oort Cloud",
"Kuiper Belt",
"Asteroid Belt"
] | D | breaking apart rocks can cause debris |
OpenBookQA | OpenBookQA-2327 | climate-change, hypothetical, solar-terrestrial-physics
Title: How much reduction of insolation (solar energy) would be required to stop global warming? Suppose a giant sheet of semi-reflective mylar (or some other kind of partial sun-screening material) was temporarily placed into space between the Earth and the Sun with the intent to lower the amount of solar energy reaching the surface of the planet.
How much solar radiation (and in what frequency ranges) would need to be filtered to cool the planet to the most-desirable global temperature? Also, would the entire planet need to be shaded or just a key area like the Equatorial region?
Obviously the plan would be to reduce the warming effect without dramatically darkening the day since so many plants require the visible spectrum of sunlight to live. It's not that hard to make an estimate.
CO2 traps about 2 watts per square meter. Direct sunlight at 1 Astronomical Unit is about 1,360 watts per square meter, but spread out over the earth, average night and day it's about 1/4th of that about 340 watts per square meter. (note, Casey's point is valid, it's probably better to use the number of watts that hits the Earth, so, my estimate is likely a bit low)
There may be more detailed and specific ways to look at it, but this is probably pretty close. If you shade enough sun to reduce 2 watts out of 340, or 1/170th, that should balance out climate change, at least at current levels.
From space, you can view the earth as a disk in terms of area needed for shade, so the 2D area of the earth is about 127 trillion square meters, and 1/170th of that, about 750 billion square meters, or 750,000 square KM, slightly larger than Texas and as you get closer to the sun, the area needed is reduced by the square of the relative distance.
Still, that's no easy task, to put up a shade the size of Texas into space and it's no easy task to keep it there as it would in effect by a huge solar sale and likely enormously heavy. It's far easier to simply build mirrors on earth than try to build something in space and I've seen that discussed as a possible solution to climate change. of-course, they'd need to be kept clean to be effective, it would require maintenance, but it's probably doable.
The following is multiple choice question (with options) to answer.
Which would block the most sunlight? | [
"a mighty oak",
"a lowly bush",
"an eagle's nest",
"a mail box"
] | A | if a tree falls then sunlight becomes available to the surrounding plants |
OpenBookQA | OpenBookQA-2328 | electrical-engineering, power-electronics, temperature
I would not recommend messing around with cooling if you want the temperature to be very constant. I would operate the unit at the high end above your highest environmental temp. Perhaps something like 40C as your constant temp and use a heating element surrounding the unit to hold the temperature up in cold environments. Heating also takes less power and equipment than cooling.
If your space constraints are not too tight, some high quality insulation would be the easiest start. Closed cell foam or ceramic fiber would work well. Vacuum insulated like a thermos beverage container might be good too look at too.
If you cant increase the form factor you will need to add a uniform heating element around the outside of the unit and control it with microcontroller and thermistor using a pid loop. This will obviously cost some additional power.
Alternatively, most temperature dependent sensors and systems don't attempt to modify their environmental temperature, but instead use a micocontroller to digitally measure the temperature and compensate the value for that temperature.
The following is multiple choice question (with options) to answer.
A person in a cold environment that needs to produce heat could | [
"think",
"jog",
"want",
"smell"
] | B | moving changes stored energy into motion and heat |
OpenBookQA | OpenBookQA-2329 | raspberry-pi, wheeled-robot
I have glossed over the challenges of noisy sensor and actuators, but the core idea has been presented--both triangulation and control should be possible in simulation, and with a little tweaking, it should work on a physical system.
The following is multiple choice question (with options) to answer.
Robotics would have great difficulty in existing if these had yet to be invented. | [
"pots",
"cats",
"desktops",
"paper towels"
] | C | a computer controls a robot |
OpenBookQA | OpenBookQA-2330 | botany, species-identification
Title: Which plant is this? I'm curious what plant this is! I found it at 37°52'23.2"N 122°16'55.3"W (north of Oakland, California, USA). That's East Indian Fennel. It's a member of the celery family. Every part is edible, including the root and the seeds. It's packed with vitamins, calcium and is used to stop restless leg syndrome, among other ailments. The feathers (leafs) can be used to wrap meat and fish before baking or eaten fresh on a green salad. Once par boiled they lose their licorice taste and can be eaten like steamed spinach. The Italians brought it over in the early 1800s and it flourished. It grows along the freeways of California and other states. I pick large batches of it for my juice extractor and other things. Look up the many medicinal uses of fennel. The flowers look similar to dill.
The following is multiple choice question (with options) to answer.
Which of these places is worst for growing oregano? | [
"field",
"farm",
"greenhouse",
"cave"
] | D | darkness has a negative impact on photosynthesis |
OpenBookQA | OpenBookQA-2331 | atmosphere, climate-change, thermodynamics, radiative-transfer
All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.
Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: Dubai construction alters local climate
Additional references
Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution
of global anthropogenic heat flux. Atmos. Oceanic
Sci. Lett., 5, 108–112.
The following is multiple choice question (with options) to answer.
High surface air temperatures, arid conditions, land overuse and over-population can all contribute to | [
"high humidity",
"icebergs",
"wildfires",
"meteors"
] | C | drought may cause wildfires |
OpenBookQA | OpenBookQA-2332 | everyday-chemistry, water, crystallography
Spin-off question:
I heard (not sure where) that each snowflake assumes a unique shape. How true is this?
Now, as I understand it, all processes proceed so as to maximize the "randomness" of its constituent particles. (Oversimplified version of the Second Law of Thermodynamics, yes, I know... just don't chew me out in the comments section...)
Yes. True.
This Law can easily be observed in, and verified by, natural processes.
Sure. Still with you.
Now the formation of snow is a natural process, agreed? The way my brain sees it, is that water droplets ought to freeze into random, and by virtue of its "randomness", highly unsymmetrical shapes. But this is not the case here!
The following is multiple choice question (with options) to answer.
Which would likely occur in nature? | [
"a horse hatches from an egg",
"a bird comes directly from the womb",
"a frog comes from its mother indirectly in the form of an egg",
"a fish comes on land to give birth"
] | C | amphibians hatch from eggs |
OpenBookQA | OpenBookQA-2333 | genetics, reproduction
http://medical-dictionary.thefreedictionary.com/Infertility
http://medical-dictionary.thefreedictionary.com/sterility
http://www.acog.org/~/media/For%20Patients/faq011.pdf
The following is multiple choice question (with options) to answer.
Which would be excluded from a list of forms of reproduction? | [
"sexual reproduction",
"bisexual reproduction",
"asexual reproduction",
"reproduction"
] | B | different organisms reproduce differently |
OpenBookQA | OpenBookQA-2334 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
Sometimes, a black-tailed deer will caution other deer of danger by | [
"waiting to hear sounds",
"slamming its front hoof to the ground",
"sending a text message",
"lying down on the ground"
] | B | a deer lives in a forest |
OpenBookQA | OpenBookQA-2335 | oceanography, sea-level, tides
Title: Why do high tides vary month to month? I've noticed that some ‘highest‘ high tides in one month are bigger than the highest high-tide of previous months. Why is this so? The dynamics of the tides are quite complex. The main idea is that gravity from the Moon and the Sun affect water (and everything else) on Earth. The issue is that there are several motions that alter the distance between the 3 systems and those motions cause interactions between the different frequencies involved. The Equilibrium Theory of Tides separates the different effects into a set of constituents by conducting a harmonic analysis. The relevant periods are:
the lunar day (period of lunar rotation), 24.84 mean solar hours.
the sidereal month (period of lunar declination), 27.32 mean solar days.
the tropical year (period of solar declination), 365.24 mean solar days.
the period of the lunar perigee, 8.85 years (1 year = 365.2421988 days).
the period of the lunar node, 18.61 years.
the period of the solar perihelion, 20940 years.
The explanation of each constituent can be rather complex (some examples in this other answer). The different amplitudes in a day and the spring-neap cycle are related to the combination of the main lunar and solar effects.
The differences in high/low tide from month to month are related to the next two main frequencies of oscillation. Mainly, the variations in Earth-Sun distance associated occurring in a period of tropical year. The lunar distance also contributes to these differences, but its cycle is much longer (~9 years). Also, the spring-neap cycle (with a frequency of half a lunar month ~13.5 days) will occur at different times of the month and can lead to differences in tidal amplitude if you compare the tides measured the same day of consecutive months.
(Source www.niwa.co.nz)
The following is multiple choice question (with options) to answer.
Over the course of a calendar month, the moon may | [
"resolve",
"burn",
"float",
"spin"
] | D | a revolution of the moon around the Earth takes 1 month |
OpenBookQA | OpenBookQA-2336 | meteorology, geophysics, tropical-cyclone
Title: What is the largest hurricane possible? With Earth getting hotter and hurricanes also getting larger I wonder; Is there a limit on how big a hurricane can physically get? I am going to take an educated guess here because it is not possible(AFAIK) to accurately predict with any known skill what several decades into the future would be like.
Given that premise the largest hurricane in the future could be the size of the tropical extent of the Pacific Ocean or the Atlantic Ocean(wherever that begins and ends). Here I am only considering the Northern(or Southern) tropical extent of the Pacific or Atlantic Ocean because as we know a tropical cyclone cannot cross the equator as explained in this in depth answer Impossible or improbable? Hurricane crossing the equator. The thought process behind this idea is that hurricanes(tropical cyclones) dissipate on coming contact with land. Hence the maximum area of the largest cyclone in the future would have to be the ocean body maximum tropical extent(typically sea surface temperature (SST) greater than 27 degrees centigrade). Just in case if people are wondering why just the tropical extent and why not more than that ? It is because once you enter into mid latitude regions frontal processes could kick in(cold core cyclones-as an example -Can a tropical cyclone form in mid latitude oceanic waters?)
So if the tropical extent of the biggest oceans increases in the future one can imagine a very large possibly synoptic scale tropical cyclone.
Here I am excluding the North Indian Ocean basin because it does not have the surface area to compete with the North Pacific or North Atlantic
Secondly from this popular science article -How strong can a Hurricane get? and this one Are Category 6 Hurricanes coming soon ?
By the end of the 21st century, human-caused global warming will likely increase hurricane intensity, on average, by 2 to 11 percent, according to a review by NOAA's Geophysical Fluid Dynamics Laboratory, revised on Aug. 30, 2017.
followed by
The following is multiple choice question (with options) to answer.
A hurricane over and near water will be strong, and as it travels further from the sea it | [
"explodes",
"expands",
"dies down",
"grows"
] | C | when a hurricane moves over land , that hurricane will decrease in strength |
OpenBookQA | OpenBookQA-2337 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
A girl wants to use a renewable resource to build a house, so she uses | [
"glass shards",
"rubber pipes",
"log portions",
"plastic spoons"
] | C | renewable resources can be used over again |
OpenBookQA | OpenBookQA-2338 | optics, astronomy, reflection, metals, telescopes
I used a good lens, which is why the effect is so small, but this shows the principle behind it.
Exhibit D
This is a microwave door - it is opaque to microwaves, but as you can see, lets visible light through. (See Faraday Cage)
Exhibit E
WiFi. It can pass through walls and doors.
It should be clear now that light doesn't exactly behave like what our brain calls "light"
Finally
I hope this helps. As you can see - WAAAY to long for a comment.
The following is multiple choice question (with options) to answer.
Which object is least likely to have any light pass through it? | [
"a dog",
"a plastic bottle",
"a prism",
"a window"
] | A | no light shines through an opaque object |
OpenBookQA | OpenBookQA-2339 | safety
Title: Capacitance and flammable liquid I'm trying to attach a sensor to some tubes to measure the level of liquids in them.
see here
One tube contains toluene and the other contains Recosol R55 (shellite).
I'm thinking of using a capacitance level sensor like this or this.
But I am concerned about the safety of doing this. Could the capacitance sensor ignite these liquids? is this even possible?
Obviously I need to check with the suppliers of the device. However, most of datasheets for level sensors omit this information. Perhaps they are not game enough to make any claims about their sensor in this regard.
I don't really understand capacitance and whether it can ignite flammable liquids. The capacitance sensor itself will certainly not present an ignition risk to your system. The sensor will be on the outside of the container, and it does not introduce any electrical potential that would cause a spark.
The way the device works is to measure the change in the sensor's capacitance depending on the dielectric effect of the liquid, which will increase as more liquid enters the electric field of the sensor (a capacitor).
The following is multiple choice question (with options) to answer.
When syrup is added to vodka, the flammable portion of the mixture will | [
"raise",
"fall",
"sink",
"settle"
] | A | denser liquids settle below liquids that are less dense |
OpenBookQA | OpenBookQA-2340 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A minuscule thing could be seen easily with help from | [
"a scope",
"a car",
"a blind",
"a mirror"
] | A | microscope is used to see small things by making them appear bigger |
OpenBookQA | OpenBookQA-2341 | electricity
Title: Why can touching an iPod charger sometimes cause one's skin to tingle? I was visiting Shanghai recently. One afternoon, while sitting on the sofa, I inadvertently brushed a family member's arm. To my surprise, I felt an unnatural tingling from his skin—quite like a mild version of the shock from a (toy) shock pen or the slightly numbing vibration from an electric shaver. I could consistently feel the tingling by running my knuckle lightly across the family member's skin.
The family member had been using an iPod Touch plugged into a Chinese power strip via the stock Apple charger. The tingling persisted as long as at least one part of his body contacted the iPod and even when he touched the metal end of the charging cable directly with his fingertips.
More observations:
The tingling persisted when he stood on a plastic stool instead of the sofa.
The tingling did not appear when we plugged the iPod into a power outlet at a hotel we later visited in a different city in China.
The following is multiple choice question (with options) to answer.
Which of the following is most likely to make a person shiver? | [
"being in a gym",
"being in a sauna",
"being in a fridge",
"being in a pool"
] | C | cool temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-2342 | thermodynamics, energy, electricity, efficient-energy-use
Title: Cutting down on power by bypassing mechanical to electrical conversions: Why not? The only answer to this I can think of is energy portability issues.
Another modern-world insanity is converting mechanical energy to electrical, only to turn it back into mechanical. The example I like to use is a refrigerator's reciprocating compressor.
If we directly attach a steam turbine's axle to the crankshaft of the compressor, we will not need to suffer losses in heat in our conversion of mechanical to electrical (at the power plant) then back to mechanical energy (in our appliance). Long ago, a primitive factory used one big engine or turbine or water wheel to rotate a set of overhead shafts, from which leather belts were suspended at intervals to power small pieces of machinery scattered throughout the factory. This arrangement was inflexible in that when the single big engine stopped, so did the entire factory, and when electricity came into common use, this overhead shafting arrangement fell quickly out of favor.
The power losses in long-distance electrical power transmission are more than made up for by the ease with which it is performed and the flexibility it affords. This makes "local power generation" as you describe it impractical because a hundred small steam turbines are much more wasteful of heat energy than one large turbine.
The only practical exception is integrated co-generation in which a small engine running on, for example, natural gas powers a generator while also spinning the shaft of a heat pump. The waste heat from the engine's cooling system makes residential hot water, the waste heat from its exhaust goes through a heat exchanger to provide hot air for space heating, the heat pump furnishes air conditioning (or pulls heat from outside the dwelling) and the electricity from the generator powers up your small appliances in the home while also charging a set of batteries.
Overall thermodynamic efficiency of such a device can exceed 95%, and examples of this technology are just now coming onto the market.
The following is multiple choice question (with options) to answer.
Within a power station meant to process coal, electricity is | [
"broken",
"reaped",
"destroyed",
"devasted"
] | B | coal is used to produce electricity by burning in coal-fire power stations |
OpenBookQA | OpenBookQA-2343 | 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.
As dry soil becomes more and more broken up, it will always contain more | [
"water",
"calcium",
"oxygen",
"rocks"
] | C | the looseness of soil increases the amount of oxygen in that soil |
OpenBookQA | OpenBookQA-2344 | Note:
Depending on where, and how frequently, you round during this function, your answers may be off a few cents in either direction. Try rounding as few times as possible in order to increase the accuracy of your result.
The following is multiple choice question (with options) to answer.
Which is more accurate? | [
"an ant gets food from photosynthesis",
"a dog gets food from photosynthesis",
"a gorilla gets food from photosynthesis",
"a palm tree gets food from photosynthesis"
] | D | a producer produces its own food |
OpenBookQA | OpenBookQA-2345 | thermodynamics, energy, electricity, efficient-energy-use
Title: Cutting down on power by bypassing mechanical to electrical conversions: Why not? The only answer to this I can think of is energy portability issues.
Another modern-world insanity is converting mechanical energy to electrical, only to turn it back into mechanical. The example I like to use is a refrigerator's reciprocating compressor.
If we directly attach a steam turbine's axle to the crankshaft of the compressor, we will not need to suffer losses in heat in our conversion of mechanical to electrical (at the power plant) then back to mechanical energy (in our appliance). Long ago, a primitive factory used one big engine or turbine or water wheel to rotate a set of overhead shafts, from which leather belts were suspended at intervals to power small pieces of machinery scattered throughout the factory. This arrangement was inflexible in that when the single big engine stopped, so did the entire factory, and when electricity came into common use, this overhead shafting arrangement fell quickly out of favor.
The power losses in long-distance electrical power transmission are more than made up for by the ease with which it is performed and the flexibility it affords. This makes "local power generation" as you describe it impractical because a hundred small steam turbines are much more wasteful of heat energy than one large turbine.
The only practical exception is integrated co-generation in which a small engine running on, for example, natural gas powers a generator while also spinning the shaft of a heat pump. The waste heat from the engine's cooling system makes residential hot water, the waste heat from its exhaust goes through a heat exchanger to provide hot air for space heating, the heat pump furnishes air conditioning (or pulls heat from outside the dwelling) and the electricity from the generator powers up your small appliances in the home while also charging a set of batteries.
Overall thermodynamic efficiency of such a device can exceed 95%, and examples of this technology are just now coming onto the market.
The following is multiple choice question (with options) to answer.
Converting electricity into different types of energy may be done by | [
"rocks",
"folding chairs",
"squirrels",
"DVD players"
] | D | electrical devices convert electricity into other forms of energy |
OpenBookQA | OpenBookQA-2346 | zoology, digestive-system, pets
Title: Is it safe to feed an adult fire salamander with slime maggots? As a reminder, maggots feed of a flesh, while fire salamander consumes his prey alive, without killing it.
Can it happen that the maggot will start eating the salamander from the inside? Although I am afraid I don't know much about fire salamanders specifically, it is certainly possible for ingested fly larvae (or larvae hatching from ingested eggs) to survive ingestion and subsequently cause intestinal damage. Parasitic infestation by fly larvae that grow inside the host while feeding on its tissue is called myiasis. Enteric myiasis (also called gastric, rectal, or intestinal myiasis to indicate the affected part of the digestive system) occurs occasionally in humans following the ingestion of cheese infested with cheese fly maggots. Casu marzu, a traditionally produced Sardinian cheese, is supposed to have live cheese fly maggots in it, and cases of bloody diarrhoea following its consumption are known. If they're dead the cheese is considered unsafe to eat (although personally I'd correct that to 'more unsafe').
The following is multiple choice question (with options) to answer.
Which of the following creatures would eat dandelions? | [
"bald eagles",
"meadow voles",
"horse flies",
"house cats"
] | B | meadow voles eat plants |
OpenBookQA | OpenBookQA-2347 | meteor
Title: Trying to identify something I saw in the sky I'm trying to identify something I saw in the sky. This occurred in central Virginia (Louisa county), US on Sunday at around 2:15 AM EST. It started as a ring of what looked like smoke, high in the sky. The ring got gradually larger. Then a small light moved out of it. The light looked like a star but it was moving about the 'relative' speed of an airplane viewed from the ground. I say relative because I think this was higher up than an airplane and so it was probably moving faster. The light had a puff behind it which was much larger than the light (so it was much bigger than the entrails of a jet plane). When I say 'big' or 'small' I mean it relative to the view of someone standing on the ground. I kept observing this light moving across the sky until I lost it in the trees.
I have not seen anything like this before. If I had to guess, I'd say it was possibly a military plane at high altitude moving at high speed. I guess it could also be a meteor that caused the ring when it hit the atmosphere and moved off at a strange angle. However, I have never seen a meteor move that slow. They usually zip fast across the sky. Maybe it's a meteor that hit the atmosphere at an angle that slowed it down? Anyone know what it could have been?
Edit: I saw this photo submitted to the american meteorologic society. It's about the same time and looks exactly like what I saw. It was from someone in PA at 2:30am.
The following is multiple choice question (with options) to answer.
A plane takes off from the ground, lights blazing, and flies into the sky. As the plane ascends and travels to its destination, | [
"the lights are brighter",
"the lights appear duller",
"the lights are closer",
"the lights are bigger"
] | B | as distance from a source of light increases , that source of light will appear dimmer |
OpenBookQA | OpenBookQA-2348 | 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 tiny daffodil is next to a large carnation. Bees looking for nectar will swarm | [
"the daffodil",
"a stick",
"a rock",
"the carnation"
] | D | as the size of a flower increases , the number of pollinators it will attract increases |
OpenBookQA | OpenBookQA-2349 | zoology, ornithology, ethology, senses, balance
Source: Weimerskirch, H., Bishop, C., Jeanniard-du-Dot, T., Prudor, A. and Sachs, G. (2016). Frigate birds track atmospheric conditions over months-long transoceanic flights. Science, 353(6294), pp.74-78.
PS: You have two questions here, specially after your edit. I suggest that you post another question regarding the spatial orientation, since asking different questions (even if they are related) in the same post is not nice, and it's a reason to close ("Too broad: Avoid asking multiple distinct questions at once"). However, it's worth mentioning that apparently birds do suffer from spatial disorientation when there is no visual cue. According to this relatively old paper, "Spatial Disorientation in Birds":
The only conclusion is that birds are susceptible and suffer from spatial disorientation, and further that the causes of spatial disorientation in birds are exactly the same as those which affect the human pilot, namely; (a) the loss of true visual cues to the horizontal; (b) inexperience in flying under such conditions where visual cues are lost;
The following is multiple choice question (with options) to answer.
If a bird has to adapt to hot or cold temperatures, it will find difficulty as it is | [
"able to chill blood",
"able to warm blood",
"able to adjust blood temperature",
"unable to control blood temps"
] | D | a bird is warm-blooded |
OpenBookQA | OpenBookQA-2350 | 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.
The organisms likely to have the waxiest leaves are | [
"birds",
"gorilla",
"humans",
"jades"
] | D | waxy leaves are used for storing water by some plants |
OpenBookQA | OpenBookQA-2351 | # 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 person wanting to find a live bear in a forest will have difficulty because bears | [
"avoid humanity",
"are domesticated",
"are friendly",
"are camouflaged"
] | A | animals usually distance themselves from humans |
OpenBookQA | OpenBookQA-2352 | particle-physics
Title: Explanation for self-rupture glass is needed I witnessed a phenomenon that I couldn't conclude its cause. Please bear with me for the length of the recall, for I merely want to include any details that might help us to investigate. I had a cooking glass lid sat on a wooden shelf that is away from the stove and oven and other heating objects. The shelf is nailed on the wall and is situated just above my eye level, and a counter top is also on the same side of the wall where the shelf is installed.
Now here comes the surprise. In a winter afternoon 2011, my room had almost the same temperature as an autumn morning, and while I was cutting my lettuce on that counter top which I pointed out in above passage, a pounding sound, as if a heavy car door slam or a tree trump falling on top of the roof, knocked its introduction from the shelf that was just above my eye level. First, I thought I may had knocked something around me off(which I didn't believe that for there wasn't anything around me to knock off); then I thought it may be my neighbor next door dropping a heavy box; last, I suspected somewhere my roof top collapsed.
But it was my third suspicion directed me to meet that glass lid I mentioned above, and I found it had ruptured completely like glacier creaked BUT still having all broken pieces bounded without any pieces scattering toward random direction! Only the nob of the lid popped out partially. Before this happened, I hadn't used that lid for cooking for years, and I didn't removed it from any heating object nor there was something on top of the lid that day, and I believe what the lid had maybe just an invisible layer of dust.
I was glad my face hadn't been stung by any glass residues, but ponder what really happen to that glass lid and why it ruptured without collapsed. Below, I attached 2 pictures of the scene from that day. If you have any similar experience or know the theory behind it, may you please drop me an explanation to this incidence? Thank you in advance.
The following is multiple choice question (with options) to answer.
A glass item will do this when power is fed to it. | [
"shirk",
"illuminate",
"shrink",
"die"
] | B | when electricity flows to a light bulb , the light bulb will turn on |
OpenBookQA | OpenBookQA-2353 | species-identification, microbiology, microscopy
Title: Identification of protozoa under microscope I observed maybe Protozoa from standing FRESH water and from slowly flowing FRESH water. I am complete dilettante. Can you tell what these creatures are?
https://www.youtube.com/watch?v=6D5ck3zNJzA&t=474s
Thank you.
Added picture for to be more specific At first glance, the organisms may hold the appearance of protozoans like ciliates. However, I am of the belief that these 'totally tubular' micro organisms are in fact diatoms.
The diatoms are a diverse range of eucaryotic microalgae which comprise a large percentage of the phytoplankton group. (Diatomaceous earth is the residual remains of their calcareous walls)
They are likely diatoms because of their apparent hard membrane, and slight brown-green pigment, typical of heterokont diatoms.
I would be unable to specify the organism to family level. However, you may wish to complete your investigation by looking under the order 'Pennales'.
For general information regarding the Diatoms, you may visit https://en.wikipedia.org/wiki/Diatom
Morphology and description available from: https://books.google.co.uk/books?id=xhLJvNa3hw0C&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
Good luck
The following is multiple choice question (with options) to answer.
Which organism likely contains chlorophyll? | [
"bamboo",
"pandas",
"protozoa",
"humans"
] | A | chlorophyll is used for absorbing light energy by plants |
OpenBookQA | OpenBookQA-2354 | evolution, vision, perception
For a broader review of polarized vision and underlying evolutionary hypotheses, the paper you linked to by Cronin et al. (2003) is a good review. I also came across a book, Polarized Light in Animal Vision. Polarization Patterns in Nature. by Gábor Horváth and Deszö Varjú and published by Springer. The front matter and table of contents are available here. It appears to be a very thorough review of polarization vision in animals.
Literature Cited
Cronin, T.W. et al. 2003. Polarization vision and its role in biological signaling. Integrative and Comparative Biology 43: 549-558.
Greenwood, V.J., et al. 2003. Behaviorial investigation of polarisation sensitivity in the Japanese quail (Coturnix coturnix japonica) and the European starling (Sturnus vulgaris). Journal of Experimental Biology 206: 3201-3210.
Snodderly, D.M., J.D. Auron and F.C. Delori. 1984. The macular pigmnent. II. Spatial distribution in primate retinas. Investigative Ophthalmology and Visual Science 25: 674-685
The following is multiple choice question (with options) to answer.
Instinctive behavior may be viewed when observing | [
"freshly hatched turtles seeking water",
"birds being trained to play games",
"cats being fed salami",
"dogs riding in cars"
] | A | An example of an instinctive behavior is a baby bird pecking at its shell to hatch |
OpenBookQA | OpenBookQA-2355 | genetics, homework, human-genetics
However I really feel like I'm wrong about these assumptions since the math really doesn't add up. The likelihood that so many carriers for a relatively rare disorder all coming together and the fact that 3 of the 4 offspring of the grandparents died with only a 25% chance all seems improbable.
It could be that John's son doesn't have the disorder and what he has is something completely different. What do the geneticists say? This is a very rough draft about the case, not verified, and should not be used for any medical conditions. Ask your own doctor. It is just for demonstrating some Mathematics and genetic passing generally.
Condition: Muscular atrophy
Differential conditions: TODO
Support: history of genetic passing in -1 and -3 generations
Disease
Muscular atrophy as a condition jumps over a generation. The environment/living of your greatgreatgrandfathers determine your grandfathers future, as a rough estimate.
The disease's common feature is recessive autosomality.
Assumptions
Autosomal recessive disease because everyone who exhibits symptoms is not be able to reproduce due to their early death.
TODO genetic passing
What is the genetic profile? Is there any other autosomal recessive diseases in the gene map?
Proposed probabilities where the random variables $X = disease$ and $Y = carrier$ such that the subscript 0, -1, -2 and -3 is about new children's, John's, parents' and grandparents' status, respectively.
Both of John's grandparents must have been carriers
\begin{equation}
P(Y_{-3}) = 100\%
\end{equation}
The probability of John's dad and any aunts and uncles having the disorder is (TODO think this again with the correct genetic passing)
\begin{equation}
P(X_{-2}) = 25\%
\end{equation}
The probability of being a carrier is for dad, aunts and uncles (TODO think this gain with the appropriate genetic passing)
\begin{equation}
P(Y_{-1}) = 50\%
\end{equation}
Disease as a process
$X \sim P_{i}(\mu, \sigma)$, $i = -3, -1, 1, ...$ where I propose the mean $\mu$ and the variance $\sigma^2$.
The following is multiple choice question (with options) to answer.
Which is activity is least likely to be inherited? | [
"how to taste food",
"how to hear sound",
"how to breathe oxygen",
"how to cook pasta"
] | D | doing chores is a learned characteristic |
OpenBookQA | OpenBookQA-2356 | homework-and-exercises, kinematics
Title: Average Velocity A car travels 100 miles in 2 hours, it then completes the return leg of the journey. How fast must it travel on the return leg to average 100mph over the total journey.
My thoughts on this are that it is impossible as if the total average was 100mph then the total time would be 2 hours but that can't be if the first leg took 2 hours.
Please tell me if I am missing something Are you missing something?
You probably are if this question was asked during a course on relativity. Anyway, this is a physics site and I'm going to make the question a bit more precise on the reference frames in which the measurements might have taken place:
We observe a car travel 100 miles in 2 hours, it then completes the return leg of the journey. How fast must it travel on the return leg for the driver to have done the full 200 miles in 2 hours?
The answer starts from the observation that during the first leg the driver will have aged $2\sqrt{1-\frac{v^2}{c^2}}$ hours, with $v/c \approx 50/670616629 \approx 7.5 \ 10^{-8}$. That is a fraction $5.6 \ 10^{-15}$ short of 2 hours.
So, the second leg the car should travel at a speed $v'$ such that the driver ages $\sqrt{1-\frac{v'^2}{c^2}} \frac{100 mi}{c}= 11 \ 10^{-15}$ hr. It follows that $v'$ needs to be a fraction $3 \ 10^{-15}$ short of the speed of light.
The following is multiple choice question (with options) to answer.
A person who knows that they drove two hundred miles today can figure out how fast they went if they know how much time was spent | [
"behind a horse",
"with ice cream",
"on the road",
"with windows down"
] | C | speed is a measure of distance travelled over time |
OpenBookQA | OpenBookQA-2357 | behaviour
References
Shimada M, Watanabe H, Komine Y, Kigawa R, Sato Y. New records of Ctenolepismacalvum (Ritter,1910) (Zygentoma, Lepismatidae) from Japan. Biodivers Data J. 2022 Nov 3;10:e90799. doi: 10.3897/BDJ.10.e90799. PMID: 36761636; PMCID: PMC9836529.
Kulma M, Bubová T, Davies MP, Boiocchi F, Patoka J. Ctenolepisma longicaudatum Escherich (1905) Became a Common Pest in Europe: Case Studies from Czechia and the United Kingdom. Insects. 2021 Sep 10;12(9):810. doi: 10.3390/insects12090810. PMID: 34564251; PMCID: PMC8471186.
Querner P, Szucsich N, Landsberger B, Erlacher S, Trebicki L, Grabowski M, Brimblecombe P. Identification and Spread of the Ghost Silverfish (Ctenolepisma calvum) among Museums and Homes in Europe. Insects. 2022 Sep 19;13(9):855. doi: 10.3390/insects13090855. PMID: 36135556; PMCID: PMC9505982.
The following is multiple choice question (with options) to answer.
Some creatures may pretend to be other creatures in order to | [
"have fun",
"confuse predators",
"entertain guests",
"dress up"
] | B | mimicry is used for avoiding predators by animals by camouflaging as a dangerous animal |
OpenBookQA | OpenBookQA-2358 | electrochemistry, ions
Is there any salt or other compound which would act similarly but not result in electrolysis (just conducting)? An approach using a classical model of electron flow
You can think of an electron flowing through a medium as analogous to a pinball bouncing around a pinball machine. The electric (potential) energy difference driving the displacement of the electron is analogous to the gravitational energy difference in the pinball machine. Now consider two pinball machines with differing numbers of obstacles to a falling pinball. The time it takes for a pinball to reach the bottom in each machine would be different by virtue of these obstacles (on average, taking more time with more obstacles). Similarly, the flow of electrons, I, in the presence of an electric potential, V, is higher for media with less resistance, R , to electron flow. We can use this model (Drude see below) to understand Ohm's law: $$I = \frac{V}{R}$$ The observation that electrons flow more readily through electrolyte solutions than non-electrolyte solutions indicates that solutions with charge carriers reduce the resistance of the media. A better understanding of why this is true at a molecular level will require a more in depth look. Notice, though, that we now have answers to your good questions!
The following is multiple choice question (with options) to answer.
Which two objects would electricity best flow through? | [
"a tin can and a plastic fork",
"a steel beam and a soda can",
"an eraser and a wooden pencil",
"human skin and rubber gloves"
] | B | if one electrical conductor contacts another electrical conductor then electricity will flow through both conductors |
OpenBookQA | OpenBookQA-2359 | So our resultant is 30.8 meters, 35.8 degrees north of west. What we can see is that if there is an obstacle in the path here, some big rock that you want to avoid, you can get to the same place by taking a different route which is kind of obvious, but now we just sort of demonstrated that that's true using analytical techniques.
The following is multiple choice question (with options) to answer.
A compass arrow points north, to the right of a person. If the person wants to go west, the would | [
"turn around",
"go straight",
"go left",
"go right"
] | B | the floating arrow on a compass always points towards the north |
OpenBookQA | OpenBookQA-2360 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
When tree roots grow, sometimes they | [
"eat worms",
"form perfect braids",
"strangle people",
"break hard objects"
] | D | if a tree is located near a sidewalk then the roots of that tree might crack the sidewalk |
OpenBookQA | OpenBookQA-2361 | Case I: The spider at $A$ moves to $B$.
The spider at $C$ can only move to $D$ or $G$ (since $CE$ isn't an edge). If the spider at $C$ moves to $D$, then there are two ways for the spiders at $F,H$ to move: $(A,C,F,H) \to (B,D,E,G)$ or $(A,C,F,H) \to (B,D,G,E)$. If the spider at $C$ moves to $G$, then there is only one way for the spiders at $F,H$ to move: $(A,C,F,H) \to (B,G,E,D)$ (because $BH$ and $DF$ aren't edges). This gives $3$ ways for the spiders at $A,C,F,H$ to move to distinct vertices if the spider at $A$ moves to $B$.
Case II: The spider at $A$ moves to $D$.
Similarly to Case I, there are $3$ total ways for the spiders at $A,C,F,H$ to move to distinct vertices if the spider at $A$ moves to $D$.
Case III: The spider at $A$ moves to $E$.
Similarly to Case I, there are $3$ total ways for the spiders at $A,C,F,H$ to move to distinct vertices if the spider at $A$ moves to $E$.
This gives us $9$ ways for the spiders at $A,C,F,H$ to end up at distinct locations. Hence, the probability of no two of these spiders ending up at the same vertex is $\dfrac{9}{81} = \dfrac{1}{9}$.
The following is multiple choice question (with options) to answer.
A bear has two cubs that she keeps in her den because outside the den a winter storm is raging. One cub crawls outside, the other stays inside, with the mother. The cub that goes outside, compared to the cub inside, is | [
"warmer",
"in the den",
"unlikely to survive",
"closer to mother"
] | C | an animal usually requires a warm body temperature for survival |
OpenBookQA | OpenBookQA-2362 | everyday-chemistry, experimental-chemistry, water, home-experiment, melting-point
Title: What kind of string to use for the ice fishing experiment for kids? Classic ice fishing experiment for kids.
I used nylon because I saw it in a stationery, and apparently that doesn't work because I guess it's too slippery. I tried thread from my mom's sewing kit, but that doesn't work either.
I'm not sure I can find yarn or kite string in the stationery or nearby so please suggest alternatives expected to be found in the average household, supermarket, grocery store or convenience store.
Also how long should we wait? The above video takes only 10 seconds while this video takes about 2 minutes (off screen). What factors influence waiting time? Amount of salt? Type of string? This resource has an explaination of the behavior, which relies on the salt-dissolved water wicking into the string. This would mean that you need a type of string which will absorb water. It's surprising to me that your nylon string doesn't work (as long as it's thick/low-density enough to absorb water, probably unlike fishing line), is it possible it has a hydrophobic coating?
I would recommend any cotton-based string or twine. Cooking twine and sewing thread is often cotton, if you have access to that. I've had no problems with these.
Edit: I just thought, that you might want to try this not in a cup of water first (like in the link above). You might potentially run into not-string-related problems if your water isn't cold enough, or if your ice gets too submerged when you put the salt on it. It's possible your nylon string is fine.
The following is multiple choice question (with options) to answer.
What could you use to thaw something quickly? | [
"water vapor",
"a refrigerator",
"a freezer",
"ice"
] | A | water vapor is a kind of water above 100 degrees celsius |
OpenBookQA | OpenBookQA-2363 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
A tree falls down in a yard, and the people who live there liked the shade the tree provided. They can regain their shade by | [
"planting flowers",
"making money",
"acquiring seeds",
"tilling gardens"
] | C | a tree can be replaced by planting a new tree |
OpenBookQA | OpenBookQA-2364 | homework-and-exercises, fluid-dynamics, evaporation
Title: On the evaporation of fluids Q. In which portion (1,2,3) there will be maximum concentration of evaporated water droplets? Or there will be uniform distribution of droplets?
Background:
Today, I noticed something really strange with my cylindrical water vessel. The water droplets that evaporated from my bottle made a perfect uniform pattern on plate.
This surprised me because my teacher told me that evaporated particles are particles of high energy and they just move randomly in any direction. But, then how is this pattern 100% uniform?
(2) Then I thought what would me the pattern of evaporated if its shape is as shown in fig.
Please note volume of region 2 is equal to volume of region 3 and greater than region 1.
My Attempt for first case
Maybe they are moving randomly, but due to uniform shape of vessel they cancel each others motion and the final result is like a uniform pattern of droplets.
My Attempt for second case
(1) Particles can follow same principle as in first case and they will have maximum concentration in region 1 with uniform shape
(2) Or they will just spread away in region 2 and 3 due to max volume region (and low pressure). And the maximum concentration will be in region 2 and 3.
Am I wrong? Because steam is a gas and gases diffuse, it will just spread out and create a uniform pattern on the plate.
And so the concentration in region 2/3 will be greater than region 1 due to higher surface area of plate.
They have a higher surface area because the height of all the regions is the same and the volume of all the regions is different.
The following is multiple choice question (with options) to answer.
What phenomenon is best described as evaporation? | [
"caffeine coming from hot cocoa",
"heat coming from hot cocoa",
"steam coming from hot cocoa",
"flavor coming from hot cocoa"
] | C | evaporation causes amount of water to decrease |
OpenBookQA | OpenBookQA-2365 | geology, mineralogy
Title: Online resources for geographical distribution of minerals I'm trying to find the geographical distribution and availability of mineral Brannerite. Is there a resource online to know or query where a certain mineral is found?
On the link page, they mention certain types of geophysical deposits where this mineral is usually found:
"In granite pegmatites and in granitic gneisses; in silicified pebble conglomerates; in hydrothermal quartz and calcite veins; detrital in placers"
If the answer to the former question is negative; Would there be online information about geographical distribution of these geological features? You did not mention why you are interested in brannerite, so I am assuming you want it as a collector's specimen and not a microscopic crystal.
Unfortunately, there is no definite source. However, there are some possibilities:
Try the Handbook of Mineralogy: http://handbookofmineralogy.org and more specifically the brannerite page. You will fine there a more detailed list of localities for that mineral.
Another option is to run a Google Scholar search for brannerite. You can find scholarly papers dealing with brannerite, and occasionally they also mention where they found the mineral or how they obtained it. Notice that in the specific case of brannerite, there are many articles dealing with brannerite structure. This may not be what you're looking for. There is also the problem of accessibility - unless you have an institutional or personal subscription to these journals, you may not be able to access the full article. However, sometimes this information can be found in the freely available abstract.
Go to Rocks & Minerals magazine and run a search there for brannerite. They may have some articles dealing with localities.
The following is multiple choice question (with options) to answer.
Mineral graphite could be found in places such as | [
"happy kittens",
"pink candles",
"wild oats",
"office supplies"
] | D | pencil lead contains mineral graphite |
OpenBookQA | OpenBookQA-2366 | only balances, deposits and withdrawals. Pollen is one of the most common allergens in the United States. 2% and specificity of 94. Then the only non-zero values of ǫijk are those with j,k= 2,3 or j,k= 3,2. [email protected] The annual rate of growth of Ontario’s population is projected to ease gradually from 1. Duke Energy today announced the completion and operation of its new 74. Give results in atomic units. If is then measured and then again, show that the probability of obtaining a second time is. For a long time it was thought that the ear responded logarithmically to sound intensity, i. Because the Hamiltonian, like most operators in quantum mechanics, is a Hermitian operator,. You too can get an idea of how much pawn shops pay you if you’re planning on selling or pawning with a pawn shop. 158), in matrix form, is H -yBoS: The eigenstates of H are the same as those of S With energy E+ — -(vBoh)/2,. The corresponding density matrix operator is given by,. Jaffe 2003 1 Introduction We have spent the first part of 8. Calculate the expectation values of potential and kinetic energies for the 1s state of of a hydrogenlike atom. Hamilton earns approximately $500,000 weekly on Broadway and is expected to surpass$1 billion in sales. Property values in Franklin County are expected to rise by double digits when results from a reappraisal are finalized this year, the Franklin County auditor's office said. Hamilton, New Zealand. Various trees, grasses and weeds create pollen, which can cause hay fever, irritate your eyes and skin. In addition, the risk-free rate must be set (along with. Let the nucleus lie at the origin of our coordinate system, and let the position vectors of the two electrons be and , respectively. Hamilton’s Propane is a family-owned-and-operated propane business, with three locations servicing 17 counties in Lower Michigan. $$I want to know if I set this up properly. The expected value of is a weighted average of the values that can take on. How to calculate expectation values of position and momentum - Real Chemistry - Duration: 10:47. --(Business Wire)--Alliance Resource Partners, L. Optimism definition is - a doctrine
The following is multiple choice question (with options) to answer.
An acre of arctic land, when compared to an acre of jungle land will have | [
"more living things",
"more life forms",
"more organisms",
"fewer living things"
] | D | cold environments contain few organisms |
OpenBookQA | OpenBookQA-2367 | entomology, biophysics, hearing
Title: How do small animals make loud sounds? Walking past the park today, I heard a cicada so loud I thought at first it must be some sort of large power tool. How is it that that very small animals like cicadas (crickets, etc.) can make such loud sounds? It seems intuitive that larger animals should be able to make louder sounds, but perhaps:
a) I just fundamentally misunderstand the physics involved
b) A theoretical larger animal should be able to make louder sounds, but cicadas are just extremely efficient, making up for their small size
c) ? The Cicada
A careful study of the noise-making apparatus of the cicada can be found in a 1994 paper by Young and Bennet-Clark.$^1$ The authors generated sounds at about 0-16 kHz at peaks on the order of 100 dB using cicadas in various stages of deconstruction. The cicada uses a resonant organ-system called the tymbal which buckles and unbuckles rapidly to produce sound. The buckling-in is caused by muscle contraction and is louder than the buckling-out (relaxation) phase. Air sacs (a feature of many other small noisemakers) serve to amplify the sound. The tymbal itself, for the species in this paper, has a resonant frequency of about 4kHz (Young, page 1017). The song of the cicada as modified/amplified by air sacs and other structures, is often around 10kHz.$^{2}$
Pure Tone vs. Diffuse Tone?
The vocalizations of large vertebrates are a complex superposition of waves that in the frequency spectrum are somewhat spread out. To the extent that a frog or a bird emits a pure tone, the energy will be confined to a narrow frequency range and this may be a strategy for achieving greater amplitude. Given comparable audio sensitivity, however, the intensity of pure tones will depend on amplitude (intensity), regardless of frequency.$^{3,4}$
Other Small Loud Animals
The following is multiple choice question (with options) to answer.
Frogs withstand noisy areas easily when they eat insects because they have | [
"croaking sounds",
"problems jumping",
"zero eardrums",
"slimy skin"
] | C | a frog eats insects |
OpenBookQA | OpenBookQA-2368 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
A creature that can move through liquid easily due to flippers is | [
"bluejays",
"felines",
"penguins",
"cattle"
] | C | flippers are used for moving in water |
OpenBookQA | OpenBookQA-2369 | fluid-statics
Title: Is this watering with gravity concept possible with physics?
I was thinking of putting together a auto watering scheme for my plants. Main objective is to just have one place to fill water, and it will disperse to several cups equally. I might have the physics wrong but i remember some force which creates suction with gravity and keeps the containers equally filled. I tried to draw the idea, and i'm wondering if anyone have any feedback on if this is possible?
The idea here is that the gravity will bring the water from the top container which stands taller, and then fills the small containers with water. The sketch is of a high reservoir, with multiple level-controlled smaller tanks.
So, it implies that the (lower level) tanks are equipped with a valve that
shuts off the water when a target level is reached: it's just like the
shutoff mechanism in the tank of a toilet. There's a float, which operates
the valve. It doesnt equalize gallons per day, though, just level-in-a-tank.
So, you can definitely find items at a hardware store to build such a system.
If, on the other hand, you want to partition a water source to multiple
destinations based on delivered water volume being equal, the usual
approach is to use a timed valve to a pressurized manifold, and use
matched emitters (i.e. drip irrigation controlled-flow drip fittings).
The physical principle of these emitters is the Bernoulli effect, they
are fabricated so that too-fast water flow in the valve pulls the
aperture shut (this sounds hard, but it isn't). Over a range
of water pressure, the drip rate stays nearly constant. They usually
require pump pressure (or water-utility pressure) though, would clog
if you just used a few feet of gravity-driven flow.
The following is multiple choice question (with options) to answer.
Fluids are relocated through a daffodil due to the | [
"ears",
"eyes",
"mouth",
"shoot"
] | D | a plant stem is the vehicle for transporting water and food from roots to the rest of the plant |
OpenBookQA | OpenBookQA-2370 | mechanical-engineering, materials, automotive-engineering
Any time you've got a hot thing that needs to be cooled by convection, the limitation is the interface between the air and the object to be cooled. A thin copper plating -- or even making the whole rotor out of copper -- isn't going to help this.
The following is multiple choice question (with options) to answer.
A person needs to use a raw material to cool an engine, so they might use | [
"H2O in a jug",
"fire in a house",
"salt in a shaker",
"corn in a stove"
] | A | if something is a raw material in a process then that something is required for that process |
OpenBookQA | OpenBookQA-2371 | evolution, psychology, sociobiology
Title: Female preference for males who are already in a relationship A common saying is that women are generally more attracted towards men who are already in a relationship, and this phenomena does seem to have its own place in popular culture that is not matched by a corresponding male preference for women who are already in a relationship.
From an intuitive viewpoint I think it would make sense from the woman's viewpoint in an system of information economics where the fact that a male is engaged in a successful relationship with another female, or several other females, might provide extra and positive information about the evolutionary value of the male.
But how about the possibility for a male to use the same trick?
Is there any empirical evidence for this behaviour at all either in humans or in other species, or is this just a cultural artefact in some human societies? If there is empirical support, is there a consensus on the plausible evolutionary pathways involved here? This is a widely researched topic in the overlap between social sciences and evolutionary biology. Evolution has become very influential in understanding human interaction and preferences.
This chapter from "The Adapted Mind : Evolutionary Psychology and the Generation of Culture" will give you an idea of how all this plays out in the big picture - its a fairly comprehensive review of many factors considered in human mate choice. The study may be psychological, but the logic is derived from biology these days. (stackexchange won't let me link to google books - you can search for the title and look at chapter 6).
Evolutionary tendencies will favor more successful offspring. But for people it includes not only the genetic qualities of the mate (appearance, height, disease resistance, health) but also social qualities (how reliable or willing a mate is to support offspring).
First off you can see that there are many many factors which women take into consideration in their preferences. Its commonly said they are more complex than men, but that's another question. You have to take a range of factors holistically including the social environment.
I can't find this particular issue addressed in the literature, but I think that it might be attractive to women in some social settings. If there is a lot competition for 'quality' mates or resources for instance - if you have very few secure males or pessimistic females might create pressure which would cause females to prefer males which were successful.
The following is multiple choice question (with options) to answer.
If blue whales have trouble finding any mates | [
"they could become overpopulated",
"their population could drop to the sum of negative two and two",
"they could all become sharks",
"they could mate with killer whales"
] | B | if all members of a species cannot produce offspring then that species will likely become extinct |
OpenBookQA | OpenBookQA-2372 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
When an animal goes into a den during cold weather they probably did this because | [
"they are escaping predators",
"their ancestors did the same thing",
"they heard on the news that war was coming",
"They are getting away from the hot sun"
] | B | hibernation is an inherited behavior |
OpenBookQA | OpenBookQA-2373 | thermodynamics, water, freezing
IMHO we now have a pretty decent picture of what is (and isn’t) happening. Remember, the objective is to make an impressive fog. It is exponentially important to have hot water in order to drive a lot of H2O into the vapor phase. It is important to do a decent job of tossing the water, in order to create sufficient surface area for evaporation to occur. It is necessary to have reasonably cold air, to cause recondensation to occur. Extreme cold is not necessary, but doesn’t hurt, and an ice-fog will be more persistent than the other kind of fog.
--- John S. Dunker, 2004, "How to Make Fog"
http://www.av8n.com/physics/ice-fog.htm
I have a few things to add:
In videos of the phenomenon, the cloud forms close to the surface of the liquid, leading to a "telescoping" effect as the water moves through the air.
One possible explanation of this is that the latent heat of freezing released by the water closest to the cold air heats the water further from the cold air. This layer of "inner water", since it is already close to boiling, will evaporate, dispersing the water molecules and quickly freezing, exposing and heating another layer, and so on.
It may seem strange that freezing water would heat surrounding water, but remember that the latent heat of freezing must go somewhere, and liquid water is more conductive than air. That, in addition to the rapid expansion and insulation provided by the water vapor (remember the Leidenfrost effect) is what allows it to disperse so quickly without bonding into a mass of ice.
I don't have enough of a background in atmospheric physics to point to relevant literature, but I hope this provides some insight into the subtleties of the phenomenon.
The following is multiple choice question (with options) to answer.
A pot of cold water, with heat now applied, may be noted to have reached its boiling point when | [
"bubbles are seen",
"food is cold",
"water is warm",
"salt is added"
] | A | boiling point means temperature above which a liquid boils |
OpenBookQA | OpenBookQA-2374 | food, decomposition
Title: Worm compost cannot have cooked food I live in the Netherlands and it is getting fashionable to compost with worms. After investigating a few websites I noticed that most websites suggested that I cannot feed the worms leftovers from citrus fruits. This seems logical. I then started noticing that people advise against feeding the worms cooked food.
I'm no biologist but I cannot imagine a reason why cooked food is bad for the worms. Could anybody explain why this might be in layman’s terms? There are a few reasons for not feeding cooked foods to worms (Eisenia spp.) in a smaller household size worm farm. It's not because the food is cooked but what it often contains.
The earthworm used in vermiculture is usually Eisenia fetida (red wigglers) though other Eisenia species are sometimes used. All Eisenia are epigeic species meaning they live in the junction of decomposing organic matter (such as leaf litter, aging manure, rotted fallen trees) and their natural food is decaying plant matter and bacteria that are also digesting the organic matter. They don't make use of small dead animals (meat and fat).
In large scale commercial vermiculture operations, leftover and past-due-date foods from restaurants, institutions, nursing homes and schools are used along with plant matter and carboard and paper. I'm not sure how they balance cooked foods but possibly much less is used than plant matter.
The fact food is cooked isn't the problem but what's in it and/or what happens to it when added to the bin. If you have leftover vegetables and fruit that's been cooked with no added salt, it's perfectly acceptable. A certain amount of sweetened cooked fruit is also fine as the worms will eat that too. But ready-made foods usually have preservatives, salt, fats and spices added. Either worms won't eat it, leading to odour caused by mouldy rotten food, or it can make them unthrifty and even killing off your worms if it's fed them repeatedly.
The following is multiple choice question (with options) to answer.
A person can get sick when eating a vegetable if it was farmed using | [
"water",
"dirt",
"insect destroyers",
"tools"
] | C | eating food that contains pesticides can have a negative impact on humans |
OpenBookQA | OpenBookQA-2375 | everyday-chemistry, stoichiometry
Assume air is, in vol %, ($N_2$,78.08%), ($O_2$,20.95%), (Ar, 0.93%), ($CO_2$, 0.04%) where the $CO_2$ percentage has been made to take up the slack in trace elements so the total for air is 100% by volume.
I want a table in atomic percent for each element for a block of EPS. The elements are C, H, N, O, Ar, Br, F. I especially want feedback if the assumptions are way out-of-line.
ADDED: Here is a quote that suggest the blowing agent, or at least part of it, stays in the foam. As stated, the foam is meant to be 'old' as in late 1980's to early 1990's. 'A wide range of concentrations of CFC-12 (dichlorodifluorocarbon) was detected in styrofoam ware. It fluctuated between a low of 32 ppm and a high of 35471 ppm in two different samples of styrofoam plates.' In abstract of Environ Monit Asses. 1991 Oct; (1-3): 413-22 'The determination of chlorofluorocarbons and extractives in the expanded and disposable polystyrene ware' by C.T. Sam & T.H. Chua.
It should be mentioned that contemporary blowing agents, like that found on Pharosproject, seem to be $CH_2$ based, like pentane. Since the vast majority of atoms of the styrene foam will be C and H, these kind of blowing agents are not of a concern to me, and they may well completely diffuse out. You do not explain the context of your analytical problem. One cannot go to an analytical chemist/analysis service and state that tell me all the compounds which are present in this foam. This can take a year. So you have to simplify the problem.
(i) If you are solely interested in atomic compositions, all you have to do is to request elemental combustion analysis for
Carbon, H, Nitrogen, Oxygen, Sulfur and Halogens. This is a standard process. They will burn a small amount of your sample and tell you the percentages of these elements.
The following is multiple choice question (with options) to answer.
The location of most C02 is pulled from the air | [
"by greenery",
"by detectors",
"by scientists",
"by people"
] | A | carbon dioxide can be found in the air |
OpenBookQA | OpenBookQA-2376 | ecology
Title: Do invasive species cause long-term damage to ecosystems they invade? Growing up in the U.S., I was warned at various times of the dire consequences of a variety of introduced pests (usually insects).
Japanese beetles, gypsy moths, and most recently the brown marmorated stink bug are all introduced pests that, at various times, were described as serious threats to our ecology.
These threats aren't confined to arthropods, either. The giant African land snail is causing a stir in Florida (indeed, Florida seems to suffer from an excessive variety of introduced species.
"Lack of native predators" is frequently cited as the primary reason many invasive species are considered such a risk to the ecology.
I understand that these introduced species can place tremendous pressure on native species that fill similar ecological niches, and may even push these species out of the region due to competition for food and habitat. However, do the overall ecologies that these species are introduced to adjust over long periods of time?
The numbers of Japanese beetles and gypsy moths don't seem anywhere as high as when I was a child. Has the ecosystem adjusted, or has the overpopulation self-corrected as the species ran low on food through over-consumption? Or are the populations still just as problematic now as they were 30 years ago, and I just am not seeing the bigger picture?
What is the long-term impact that we've seen from invasive, introduced species? Is there a significant difference on the long-term impact between introduced flora, arthropods, or mammals? The answer really depends on how you think of invasive. One extreme answer is to say that all things are relative, and that the concepts of local and invasive are all relative. This matters to a certain extent because ecologists draw a fuzzy line between invasive and naturalized. You could start with some basic species that we all think of as either good, local, or neutral. Take the earthworm. Most people think of it as a common native species, but the earthworm is actually an invasive species that has radically changed much of North America that came over with the Europeans. Similarly, brown trout are also invasive, coming to the US in the 1800's.
The following is multiple choice question (with options) to answer.
Which of the following would be excluded from a list of ecosystems? | [
"desert",
"snow",
"rain forest",
"tundra"
] | B | the Earth contains many ecosystems |
OpenBookQA | OpenBookQA-2377 | python, performance, physics, genetic-algorithm
Title: Evolutionary algorithm to optimize the range of a glider I created an evolutionary algorithm that optimises the range of a "glider"...ignore the accuracy of the physics behind the problem!
Any comments on how to improve the algorithm/my coding style would be greatly appreciated.
If it helps, here is the link to the github repository.
from __future__ import division
import random
import math
import bitstring
POPULATION_SIZE = 8
N_ITER = 2000
#Parameters used to evaluate the aircraft performance
V = 10
RHO = 1.2
HEIGHT = 100
class Param:
def __init__(self, min_val, max_val, value = None):
"""
Attributes and methods associated with an aeroplane parameter which is to
be optimised
Inputs:
min_val: Minimum allowed value for the paramter
max_val: Maximum allowed value for the paramter
value: If provided, the inital value of the paramter
If not provided, a random value is generated
The range between the min_val and max_val will be split into 255 "steps" to
allow the value to be encoded using 8 bits.
"""
self.min_val = min_val
self.max_val = max_val
self.step_size = (self.max_val - self.min_val) / 255
#if a value is provided, round it to an allowed value
if value:
self.step = value // self.step_size
self.val = self.step * self.step_size
#generate a random value
else:
self.val = value
self.generate_value()
def generate_value(self):
"""
Generates a random starting value
"""
self.step = random.randint(0, 255)
#randomly generate a value within the allowed range
self.val = self.min_val + self.step * self.step_size
def update(self, step):
"""
Updates the parameter value based on the "step" paramter, which will be in
the range 0 -> 255
"""
self.val = self.min_val + step * self.step_size
The following is multiple choice question (with options) to answer.
A hang-glider that is soaring runs into gales head-on. The gales | [
"sinks the glider",
"speeds the glider",
"crashes the glider",
"slow the glider"
] | D | friction causes the speed of an object to decrease |
OpenBookQA | OpenBookQA-2378 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
Which of the following would likely use a compass to reach their destination? | [
"a taxi driver",
"a middle-schooler",
"a dog",
"a 1700's pirate"
] | D | a compass is used to navigate oceans |
OpenBookQA | OpenBookQA-2379 | atmosphere, moon, sun
Title: Why were both the sun and the moon red today? Today was a normal day, except the sun and moon colors were strange. After 5pm, the sky was covered with cirrostratus-like translucent clouds and the sky was a blend of blue and grey.
Everything would be fine, except that the sun was orange between 4-5pm. Then by around 5-6pm, the sun was completely red like blood even though it was still high up, and it was 1+ more hour to sunset.
Then, I didn't look at the sky until 8pm when it was already dark. When I went out, the moon was red just like the sun couple hours before.
The whole thing I saw from around south side od Chicago on US Labor Day (4 Sep, 2017). I didn't take pictures of the sun unfortunately because I disregarded its color, but I took pictures of the moon.
Here's how the moon looked through my phone camera, through binoculars:
Here is a similar picture but edited so that the moon looks exactly like I saw it with naked eye:
What can thia be caused by? (As of writing this at 10:06pm the moon is still red, and it is 6 hours since both the sun and the moon were red/orange)
EDIT: I also didn't see anything about this phenomenon in the media which is strange, and once again, this was seen from Chicago. Smoke. There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering. The smoke particles effectively cause the light to reflect in different directions, so you see more colors.
See below for the HMS Smoke Polygons for the day, which clearly shows smoke over your region from the intense smoke/wildfire activity in the Pacific Northwest. You can also see the NASA Worldview composite of VIIRS visible imagery for the day, with fire locations in red.
The following is multiple choice question (with options) to answer.
Tom noticed it was getting gloomy outside at only two in the afternoon. Which of these might be the cause? | [
"the witch at the top of the hill has placed a spell on the town",
"a warm front has moved overhead",
"a funeral is about to start at the church across the street",
"the earth is moving through a dark area of space"
] | B | a warm front causes cloudy and rainy weather |
OpenBookQA | OpenBookQA-2380 | sun, vision, biology, eclipse, laboratory-safety
Title: Why aren't 100% UV blocked sunglasses safe to view an eclipse with? I am not planning on staring into the sun during an eclipse or any other time.
I have been reading about how no variety of regular sunglasses are safe enough to view the eclipse with. I'm not talking about being able to see things clearly, but just actual eye safety.
From what I understand it is the ultraviolet light that causes damage to the retina, but maybe it is more complicated.
How do my eyes get hurt if I am looking at the sun through so called "100% UV protection" and what makes the eclipse glasses sold in stores different?
edit: To clarify this is not about how the rays from the sun are dangerous, but about why "100% UV blocking" sunglasses fail. Do other dangerous rays get through? Is the "100%" marketing? Essentially, in what way are the best consumer sunglasses inadequate for looking at an eclipse.
Answers about pupil dilation and what makes an eclipse more dangerous for naked-eye viewers are not what I'm after. You are correct that almost always it is the UV content of sunlight and not its power that is the main hazard in staring at the Sun.
The lighting during a total eclipse is one of those situations outside the "almost always". Eclipses did not weigh heavily on our evolution, so we are ill kitted to deal with them.
Moreover, UV sunglasses are not designed to attenuate direct sunlight, only reflected sunlight.
Normally, the eye's pupil is shrunken to about a millimeter diameter in bright sunlight. This means that it admits about a milliwatt of sunlight, which, for healthy retinas, is nowhere near enough to do thermal damage (see my answer here for further discussion).
During an eclipse, the pupil dilates to about $7\,\mathrm{mm}$ diameter to adapt for the low light levels of the eclipse's twilight. Thus its aperture is fifty times bigger than it normally is in sunlight. This means it admits a great deal more UV than normal (and the corona, at $100\,000\,\mathrm K$, radiates a great deal of this). You're getting about $50$ times the dose you would normally get even looking directly at the Sun.
The following is multiple choice question (with options) to answer.
Which would be prevented by safety goggles? | [
"skin burns",
"blindness",
"fashion disasters",
"bad grades"
] | B | safety goggles are used for protecting the eyes during experiments |
OpenBookQA | OpenBookQA-2381 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
A person wanting to do something good for the environment will | [
"have seven more children",
"throw away plastic containers",
"put plastic in special containers",
"burn old rubber shoes"
] | C | recycling has a positive impact on the environment |
OpenBookQA | OpenBookQA-2382 | mass, astronomy, measurements, asteroids
$$ {\bf g}_{\rm rad} = \left(\frac{L_\odot a^2}{4 m r^2}\right) e_r\ .$$
Thus the trajectory will be determined by an acceleration that is slightly smaller than the gravity due to the Sun by an amount that depends on the ratio the area it presents to the Sun divided by its mass.
This could well be a tiny perturbation - though obviously gets bigger the more like a "solar sail" the object is (i.e. a large $a^2/m$) - but of course the effects are integrated over the course of its passage through the Solar System.
It was exactly this type of argument that lead Bialy & Loeb (2018) to suggest that "Oumuamua" (the first example of an identified interstellar rock) had a non-gravitational acceleration that could be explained if it had a high area to mass ratio, such that it might be less than a cm thick and weigh only of order 1000 kg.
The problem with using this technique is that you have to eliminate or separate it from other sources of non-gravitational acceleration - like outgassing from cometary material.
The following is multiple choice question (with options) to answer.
A small dish that is in space will do this as it nears an enormous mass. | [
"be blown up",
"be yanked in",
"be pushed away",
"be evaporated"
] | B | as distance from an object decreases , the the pull of gravity on that object increases |
OpenBookQA | OpenBookQA-2383 | statistical-mechanics, atmospheric-science, density
A limnic eruption, also referred to as a lake overturn, is a rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud that can suffocate wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, or explosions can be a trigger for such phenomenon. Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes.
Picture 1: one of a number of cattle killed by a limnic eruption at Lake Nyos, Cameroon.
We can occasionally prevent the buildup of carbon dioxide by degassing the body of water.
Picture 2: a siphon used by French scientists to de-gas Lake Nyos. The carbon dioxide emerges from its deposits and bubbles into the water, floating to the top.
The following is multiple choice question (with options) to answer.
Kettles are lakes which are formed when chunks of glaciers | [
"freeze",
"drown",
"float",
"dissipate"
] | D | a kettle is formed when chunks of ice left by glaciers melt |
OpenBookQA | OpenBookQA-2384 | 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.
A thing that is experiencing transpiration is likely to be | [
"a shovel",
"a doorbell",
"a hydrangea",
"a mouse"
] | C | transpiration usually happens in the leaves of a plant |
OpenBookQA | OpenBookQA-2385 | 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.
Predators which rely on small rodents for food will do what when rodents all die off? | [
"become vegetarians",
"increase in population",
"have more food",
"have lower numbers"
] | D | as the supply of food in an environment decreases , the population of animals in that environment will decrease |
OpenBookQA | OpenBookQA-2386 | agriculture
The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of gruel and porridge rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of pearl barley and groats and oats in the form of oatmeal. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When Samuel Johnson wrote his dictionary, he famously defined oats as: "A grain which in England is generally given to horses, but in Scotland supports the people." A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.
In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area, Ph.D. thesis, University of Helsinki, 2007 (online)
The following is multiple choice question (with options) to answer.
Which two crops would humans likely avoid in a famine? | [
"tobacco and cocoa",
"corn and peas",
"wheat and rice",
"melon and beans"
] | A | humans eat crops |
OpenBookQA | OpenBookQA-2387 | the-moon, night-sky
And another useful reference at planetarium.madison.k12.wi.us:
At the beginning of Winter, when it's nighttime all of the time, the moon would be in the sky for the 2 weeks closest to Full Moon, and then below the horizon for the next 2 weeks. And at the beginning of Spring (click on the graphic), when the sun is at sunrise all of the time, the moon would be up in the sky for the 2 weeks closest to First Quarter (waxing), and then below the horizon for the next 2 weeks.
The animated graphic above shows what we would see from the North Pole if we went out every day at noon, for 14 days in a row, from March 1st to March 14, 2006. We start with a thin crescent moon near the horizon, and end with a full moon near the horizon. Halfway through, the First Quarter moon would be when the moon is highest above the horizon.
Keep in mind, that if you were observing the moon constantly, throughout a 24 hour period, the moon would seem to move to the right in the sky along with the sun, stars, and planets due to the Earth's rotation. Nothing would seem to rise and set: they would just seem to circle around you.
The following is multiple choice question (with options) to answer.
A boy is waiting to see a full moon. He notes that the full moon is tonight, and looks at it. If he wants to see another, he must wait | [
"a week",
"a day",
"a fortnight",
"a month"
] | D | each of the moon 's phases usually occurs once per month |
OpenBookQA | OpenBookQA-2388 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
A shark sees a meal but it runs into a thick cloud of ink, blinding it. Which of the following creatures could be responsible? | [
"a whale",
"a sea lion",
"an octopus",
"a shark"
] | C | octopuses releasing ink into the water causes predators to have difficulty seeing the octopus |
OpenBookQA | OpenBookQA-2389 | 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.
Where deer and rabbits generally reside tends to be | [
"dark caverns",
"leaf colored",
"under water",
"lava filled"
] | B | a forest environment is often green in color |
OpenBookQA | OpenBookQA-2390 | thermodynamics, water, freezing
IMHO we now have a pretty decent picture of what is (and isn’t) happening. Remember, the objective is to make an impressive fog. It is exponentially important to have hot water in order to drive a lot of H2O into the vapor phase. It is important to do a decent job of tossing the water, in order to create sufficient surface area for evaporation to occur. It is necessary to have reasonably cold air, to cause recondensation to occur. Extreme cold is not necessary, but doesn’t hurt, and an ice-fog will be more persistent than the other kind of fog.
--- John S. Dunker, 2004, "How to Make Fog"
http://www.av8n.com/physics/ice-fog.htm
I have a few things to add:
In videos of the phenomenon, the cloud forms close to the surface of the liquid, leading to a "telescoping" effect as the water moves through the air.
One possible explanation of this is that the latent heat of freezing released by the water closest to the cold air heats the water further from the cold air. This layer of "inner water", since it is already close to boiling, will evaporate, dispersing the water molecules and quickly freezing, exposing and heating another layer, and so on.
It may seem strange that freezing water would heat surrounding water, but remember that the latent heat of freezing must go somewhere, and liquid water is more conductive than air. That, in addition to the rapid expansion and insulation provided by the water vapor (remember the Leidenfrost effect) is what allows it to disperse so quickly without bonding into a mass of ice.
I don't have enough of a background in atmospheric physics to point to relevant literature, but I hope this provides some insight into the subtleties of the phenomenon.
The following is multiple choice question (with options) to answer.
If an icicle melts, or steam condenses, that matter would | [
"sing",
"fry",
"rot",
"dribble"
] | D | matter in the liquid state drips |
OpenBookQA | OpenBookQA-2391 | species-identification, entomology
Title: Bug on wall identification request I've been finding a few of these on the same wall of my apartment the path month. Size is maybe 3-5 mm.
I live in an apartment in Toronto Canada.
Thanks in advance! Without clearer photos it is pretty hard to say, however, I think it is likely to be one of the Dermestidae family of beetles.
These include a bunch of common pests in the household, including "carpet beetles" (Anthrenus sp.), and the larder beetle (Dermestes lardarius).
I think this is most likely to be a carpet beetle, given the light/dark mottled pattern on the shell.
The following is multiple choice question (with options) to answer.
A camouflaged creature in a patterned room will be | [
"quick to spot",
"fast to locate",
"rough to spot",
"easy to see"
] | C | An example of camouflage is when something is the same color as its environment |
OpenBookQA | OpenBookQA-2392 | ecology
Title: Do invasive species cause long-term damage to ecosystems they invade? Growing up in the U.S., I was warned at various times of the dire consequences of a variety of introduced pests (usually insects).
Japanese beetles, gypsy moths, and most recently the brown marmorated stink bug are all introduced pests that, at various times, were described as serious threats to our ecology.
These threats aren't confined to arthropods, either. The giant African land snail is causing a stir in Florida (indeed, Florida seems to suffer from an excessive variety of introduced species.
"Lack of native predators" is frequently cited as the primary reason many invasive species are considered such a risk to the ecology.
I understand that these introduced species can place tremendous pressure on native species that fill similar ecological niches, and may even push these species out of the region due to competition for food and habitat. However, do the overall ecologies that these species are introduced to adjust over long periods of time?
The numbers of Japanese beetles and gypsy moths don't seem anywhere as high as when I was a child. Has the ecosystem adjusted, or has the overpopulation self-corrected as the species ran low on food through over-consumption? Or are the populations still just as problematic now as they were 30 years ago, and I just am not seeing the bigger picture?
What is the long-term impact that we've seen from invasive, introduced species? Is there a significant difference on the long-term impact between introduced flora, arthropods, or mammals? The answer really depends on how you think of invasive. One extreme answer is to say that all things are relative, and that the concepts of local and invasive are all relative. This matters to a certain extent because ecologists draw a fuzzy line between invasive and naturalized. You could start with some basic species that we all think of as either good, local, or neutral. Take the earthworm. Most people think of it as a common native species, but the earthworm is actually an invasive species that has radically changed much of North America that came over with the Europeans. Similarly, brown trout are also invasive, coming to the US in the 1800's.
The following is multiple choice question (with options) to answer.
When would a habitat be considered destroyed? | [
"all trees have been razed",
"the lake is overflooded",
"the desert experiences high winds",
"the tundra's average temperature increases slightly"
] | A | if a habitat is removed then that habitat is destroyed |
OpenBookQA | OpenBookQA-2393 | species-identification, zoology, bone-biology, bone
Title: What is this bone from? This object showed up on my fire escape in New York city. It appears to be some kind of bone. It's a bit smaller than an adult human hand. What animal is it from? Given the size and thin/elongated ilia as well as the urban location, I think a domestic cat and/or a raccoon are likely candidates. I'm leaning toward cat.
Cat pelvis:
VCA Hospitals
Ventral view of domestic cat pelvis; Source: BoneID
Raccoon Pelvis
Anterior view of raccoon pelvis; Source: BoneID
I'm not an expert in differentiating these two species' bones. I will note that your specimen is more or less in between the sizes of these two species. Your size is probably closer to the raccoon, but a cat is just more likely given the location.
The most noticeable trait that stands out to me is the size/pointedness of the ischial tuberosity, which better matches that of the cat.
The following is multiple choice question (with options) to answer.
A raccoon be most likely to live near which of the following? | [
"a human garbage dump",
"an icy barren tundra",
"an arid desert plain",
"a tropical rain forest"
] | A | raccoons eat garbage |
OpenBookQA | OpenBookQA-2394 | waves, atmospheric-science, turbulence
The clouds form if the rising air reaches the lifted condensation level before the updrafts are stopped by an inversion or stable layer. The air is (relatively) clear above the downdrafts. If the convection rolls were perfectly circular, the cloud row spacing would be twice the height of the inversion/stable layer.
Mathematically, there are many wavelength solutions to convection, but the wavelength that dominates is the fastest growing one. In the Boussinesq approximation, which is reasonably valid here, this turns out to have a wavelength of $2\sqrt{2}\sim 3$ times the height of the convecting layer, i.e. slightly flattened. (See, for example, Eq. 21 of Kuettner (1971) "Cloud bands in the earth's atmosphere: Observations and Theory".)
For typical cumulus cloud heights of $\sim 2$ km, we expect typical spacings of about $6$ km.
Wave, lee, or mountain clouds are lines of clouds downwind of an obstacle (such as a mountain range). The lines are parallel to the wind direction. These are buoyancy waves where wind pushes denser air over an obstacle (e.g. a mountain range) and it ends up above less dense air on the other side. This dense air starts to fall but it overshoots into even higher density air at lower altitude, which forces it back up, and the air ends up bouncing up and down until the oscillations die out. If the vertical temperature profile of the air then is known, it is possible to estimate the vertical buoyancy angular frequency
$$N=\sqrt{\frac{g}{\theta}\frac{d\theta}{dz}}$$
The following is multiple choice question (with options) to answer.
A cloud that begins to precipitate onto the ground is | [
"fluttering",
"laughing",
"crowing",
"leaking"
] | D | precipitation is when water falls from the sky |
OpenBookQA | OpenBookQA-2395 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
A deer eats plants, which are producers, and they also | [
"eat marshmallows",
"burn bridges",
"eat cats",
"create sugars"
] | D | a producer is a source of sugar in an ecosystem |
OpenBookQA | OpenBookQA-2396 | star, orbit, the-sun
Title: Does the Sun turn around a big star? The Moon orbits the Earth.
The Earth orbits the Sun.
Does the Sun orbit another bigger star?
If so, does this star orbit, in turn, a very big star?
... etc ...
What are all the intermediate subsystems up to motion around the center of the Milky Way? The Sun is not within the gravitational sphere of influence of any other star. The centre of mass of the solar system (which is very close to the Sun) instead orbits in the general Galactic gravitational potential. Because this has a roughly cylindrical symmetry (the Galaxy is basically a disk with a bulge in the middle), this means that it executes a (roughly) circular orbit around the centre of the Galaxy, taking about 230 million years to do so. At the same time it is wobbling in the vertical plane of the Galactic disc, up and down with a cycle of about 70 million years (see How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it? )
There is really nothing intermediate because the stars in the milky way form a "collisionless system" they don't really interact gravitationally on an individual basis. Stars can be influenced by perturbations in the smooth Galactic potential caused by massive star clusters, giant molecular clouds and spiral arms. This is thought to be why the velocity dispersions of stars around regular circular orbits increases with age.
The following is multiple choice question (with options) to answer.
As the Earth rotates around a star, the world may | [
"freeze solid",
"become miniature",
"explode",
"enjoy various seasons"
] | D | the Earth revolving around the Sun causes the seasons to occur on its axis |
OpenBookQA | OpenBookQA-2397 | optics, everyday-life
Title: Weird phenomenon when passing light through a net Came across this weird "phenomenon" yesterday and looked everywhere for the reason.
when placed at a certain point the light illuminates only the vertical strings of the net.
creepy ...
given the light source must be in the same orientation (horizontal/vertical)
I used this:
(these pictures are hideously big sorry about that)
what I thought to be the answer was since the light source is vertical here
more intensity of light hits the vertically oriented strings
Is that right? Cause I'm not so convinced. Just to elaborate on @Claudio Saspinski's answer, consider that for a non point source of light there are always umbra and a penumbra parts to the shadow as illustrated here (from https://www.researchgate.net/figure/Earths-penumbra-and-umbra_fig2_318124646):
For each horizontal string, there is a small umbra and a large penumbra due to the orientation of each string in relation to the light source - the light source is large in the vertical direction - and the spacing above and below the string. At each point along a vertical string, there is a larger umbra and smaller penumbra due to the horizontal narrowness of the light source and the blocking of light by the parts of the string above and below the point under consideration.
The following is multiple choice question (with options) to answer.
A person wanting to signal with light could redirect sunlight with | [
"a shoe",
"a steel dish",
"a teabag",
"a cat"
] | B | a mirror reflects light |
OpenBookQA | OpenBookQA-2398 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
A dog needs to be able to sense something visually, so it makes sure it can | [
"read",
"view",
"walk",
"hear"
] | B | seeing is used for sensing visual things |
OpenBookQA | OpenBookQA-2399 | Here, since counting the number of total fish in the pond is hard, they tagged 50 and let them disperse evenly in the population. Then they caught 50 and found 2 to be tagged. So approximately 4% of the fish were tagged. So 50 is 4% of the entire fish population of the pond. Note that the method uses huge approximation because of the small sample number. If 1 more tagged fish were caught among the 50, it would change the approximated fish population number by a huge amount. But they have given us that "the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond" so we can make this approximation.
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Re: In a certain pond, 50 fish were caught, tagged, and returned [#permalink]
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27 Mar 2016, 12:49
Is it a 600 level question or more?
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Re: In a certain pond, 50 fish were caught, tagged, and returned [#permalink]
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21 Feb 2017, 02:30
Hi can you help me with this problem? The last part of the problem It is not clear for me. I don't know if I have to use 50 fish or 48 fish still in the pond
- 2 fish tagged / 50 in the second catch
- 48 fish are still in the pond
So the equation is:
48 fish tagged in the pond/Tot in the pond = 2 fish tagged out/50 fish catched
Tot in the pond = 48*2/50 = 1200 (aprox. 1250) --> answer is C
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Re: In a certain pond, 50 fish were caught, tagged, and returned [#permalink]
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30 Apr 2017, 11:41
Sachin9 wrote:
so, x * 4% = 50
The following is multiple choice question (with options) to answer.
As a pond is slowly evaporated, the food for ducks in that area | [
"is tasteless",
"is more",
"is booming",
"is less"
] | D | as available water in an environment decreases , the amount of available food in that environment will decrease |
OpenBookQA | OpenBookQA-2400 | Here is one solution in $12$ pieces.
• Six of the pieces here only have crust on one corner, but didn't the problem say absolutely none? – Trejkaz Sep 2 '13 at 5:29
• @Trejkaz: The requirement is only that the measure of crust included in some piece $A_i$, i.e. $\lambda(A_i \cap \partial D)$, be 0. A single point of idealized zero-thickness crust is OK since that has measure 0. – The_Sympathizer Sep 2 '13 at 5:43
• Someone has to ask this: What if we really require $A_i\cap \partial D = \emptyset$ for at least one $i$, that is at least one piece, including its boundary, must lie entirely in the interior of the disk? – Jeppe Stig Nielsen Sep 2 '13 at 21:48
• @JeppeStigNielsen: that appears to be an open problem – Robert Israel Sep 2 '13 at 22:22
• @mike4ty4 It's fair enough to have ideals, but someone who is thinking more about the pizza than the semantics will probably consider a 0-width crust to be less than ideal. Illustrating the danger of stating mathematical problems in real-world terms which people might relate with. :D – Trejkaz Sep 3 '13 at 6:45
If this violates the parameters in a clear way, consider this a teaching opportunity. Would this count:
The following is multiple choice question (with options) to answer.
The crust under everyone's feet is | [
"a tribe of human-like beings that live underground",
"the best pizza crust around",
"the ice that forms in cold regions",
"the outer covering of the third planet from the sun"
] | D | the crust is a layer of the Earth |
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