source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3701 | thermodynamics, energy, temperature, estimation
Title: What would happen if a 10-kg cube of iron, at a temperature close to 0 kelvin, suddenly appeared in your living room? What would be the effect of placing an object that cold in an environment that warm? Would the room just get a little colder? Would it kill everyone in the room like some kind of cold bomb? What would happen?
Don't think about how the cube got there, or the air which it would displace. Nothing overly dramatic, though it would be cool to look at. The cube would very quickly become covered by a layer of nitrogen/oxygen ice as the air which came into contact with it froze. Further away, you'd see condensation of water vapor into wispy clouds, which would swirl around the block due to the air currents generated by the sudden pressure drop.
Other than that, as long as you aren't in immediate thermal contact with the block, you wouldn't notice much other than that the room cools down. Here's a video I took of a vacuum can that was just removed from a dewar of liquid helium at 4 kelvin. It's maybe 5 kg of copper, not 10 kg of lead, but I'd say that's close enough to get the idea.
You can see one of my coworkers climbing down into a pit below it; he had to be careful not to bump his head on it, which would have really ruined his day, but there was no fatal cold bomb :)
The following is multiple choice question (with options) to answer.
during the winter, a man's central heating stops functioning. Which of these could be a lifeline? | [
"cranking on the air conditioner",
"leaving the oven lid open",
"leaving the fan on",
"leaving the window open"
] | B | an oven is a source of heat |
OpenBookQA | OpenBookQA-3702 | ruby, html, ruby-on-rails, active-record, erb
Rails.cache.fetch([self.name, "previous_year_count"], expires_in: expiry) do
self.previous_year.count
end
end
end
The following is multiple choice question (with options) to answer.
When a person expires they | [
"come back alive",
"rejuvenate",
"decompose",
"rejoice"
] | C | dead organisms rot |
OpenBookQA | OpenBookQA-3703 | 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.
An organism that has an unusual habitat on it's back is | [
"carrier snails",
"feelings",
"magic",
"love"
] | A | when a habitat can support living things , living things can live in that habitat |
OpenBookQA | OpenBookQA-3704 | thermodynamics, visible-light, temperature, thermal-radiation, biology
Title: Why are people dark skinned in hotter areas despite dark colour absorbing the most heat? I’m not sure if the reason is in the field of biology or more towards physics but as my reasoning is based on the physics part being that perfectly black bodies are perfect absorbers of heat and light while white is a perfect reflector but we have darker skinned humans near equator and lighter skinned people (as well as animals like polar bears) near the poles, I’ve posted it on physics stackexchange. Also, if the answer is based on the biology of animals and this should belong to biology stack exchange, feel free to let me know. This is a bio question.
The biggest threat to fitness is not lack of cooling, but damage from UV rays. A pigment in black (actually all skin to differing degrees) absorbs the UV so that skin cells don't.
Fair skinned people, from higher latitudes, have another risk to their fitness which is a lack of vitamin D which is produced by the skin when exposed to UV.
As a result of this, fair skinned people in the tropics get more skin cancer than otherwise, and dark people are more likely to have a vitamin D deficiency if far from the tropics.
The following is multiple choice question (with options) to answer.
If a person wants to move heat quickly, they could use the sun's warmth. The best thing for absorbing it would be | [
"a brass sheet",
"a wool cap",
"a rubber duck",
"a plastic ball"
] | A | metal is a thermal conductor |
OpenBookQA | OpenBookQA-3705 | homework-and-exercises, electromagnetism, magnetostatics
Title: Cylindrical shell in magnetic field Exercise: 'Infinitely long cylindrical shell of inner radius a and outer radius b of material of magnetic susceptibility χ is placed in otherwise uniform magnetic $B_0$ perpendicular to cylinder's axis. What is the resulting magnetic field. Hint: in this problem field H can be expressed through scalar potential $H = -\nabla{w}$.'
I found the general formula (Coordinate system: $\textbf{B}_0=|B_0|\hat{\textbf{x}}$, $x=r\cos{\phi}$) for potential w in three possible zones.
The inside of cylinder (r < a): $w(r,\phi) = k_1r\cos{\phi}$
The shell (a < r < b): $w(r,\phi) = (k_2r+\frac{k_3}{r})\cos{\phi}$
The outside cylinder (b < r): $w(r,\phi) = (-\frac{B_0}{\mu_0}r+\frac{k_4}{r})\cos{\phi}$
In order to find coefficients, I need to know boundary conditions. What are boundary conditions are at $r=a$ and $r=b$? The magnetic boundary conditions at an interface are:
$$\mathbf{B}_{in,\perp} = \mathbf{B}_{out,\perp}$$ and
$$\mathbf{H}_{in,||} = \mathbf{H}_{out,||}$$
Here, $\mathbf{H}= - \nabla w$ and $\mathbf{B}= \mu_0(\mathbf{H} + \mathbf{M}) = \mu_0 [- \nabla w + \chi (- \nabla w)]$.
With these equations, you can set the boundary conditions at the two interfaces for the magnetic scalar potential $w$.
The following is multiple choice question (with options) to answer.
An electromagnet contains cylindrical what? | [
"plate armor",
"wind",
"water",
"air"
] | A | an electromagnet contains cylindrical ferrous metal |
OpenBookQA | OpenBookQA-3706 | planet, orbit
Title: Do the orbits of planets change sometimes? Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it? Yes, the orbits change massively over time. For example, Earth's eccentricity (how close to a circle the orbit is), its axial tilt (what causes seasons), and precession (which direction the Earth's spin axis points) change on these huge cycles, tens of thousands to hundreds of thousands of years long. They are caused by the pull of the other planets, mainly Jupiter and Saturn (since they are so huge), as well as the physics of inertial reference frames. These are known as the Milankovitch cycles. Here is a neat video explaining what each of the cycles are in detail. That video is about Earth, but the same concepts apply to all the other planets too, just on different amounts and timescales.
An asteroid hitting a planet would technically change its orbit, however how much is questionable. An asteroid a couple km across would barely nudge the Earth since the Earth is bigger by many orders of magnitude. It would also destroy everything on the planet, but thats another story. Way back in the solar system's formation, when Thea hit Earth (theoretically) it was much closer in size than the Earth, so no doubt that it caused a much more significant shift in orbit.
The following is multiple choice question (with options) to answer.
What does the earth orbit that causes the seasons to change? | [
"mercury",
"venus",
"pluto",
"plasma star"
] | D | the moon orbits the Earth |
OpenBookQA | OpenBookQA-3707 | seeds
Title: Could potatoes that have been refrigerated for 142 days still sprout? I know that potatoes can still sprout even after being refrigerated, but could you refrigerate them for 142 days still use them as seeds to grow more plants after that?
As for the temperature of the fridge, look at this.
Considering that, what would be likely?
What about frozen or hermetic potatoes?
If anyone's wondering why I'm asking such a strange question, here's why. Yes, it is very common to do this on farms. I have grown potatoes that I stored loosely in my basement (~5 degree temperature during the winter when they would be stored) for about 6 months at a time every year for the past 20 years.
The following is multiple choice question (with options) to answer.
If a field is planted with something that will be sold later in the refrigerated section, then that something was intended to be consumed by | [
"elephants",
"toddlers",
"bears",
"bees"
] | B | humans eat crops |
OpenBookQA | OpenBookQA-3708 | the-moon, moon-phases
Title: Red cresent moon Yesterday night i witnessed something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is usually on the upper right of the night sky and white in colour. On further inspection with my binoculars i noticed it was lowering down until it was hidden by the mountain range (5km away) next to my building, this all occurred within a few minutes (about 5).
Tonight i saw the moon (crescent) had again returned to its normal position.
Please explain the cause for this, i'm completely baffled!
(Sorry for the poor wording, i'm not familiar with all the astronomical terms!) The dull red color has been due to atmospheric causes, like the reddish sun close to sunset. There hasn't been an astronomical reason for the reddish color.
A few days after New Moon moonset occurs short after sunset, so you won't see the Moon high over the horizon at those evenings. With each day the Moon is a little higher above the horizon after sunset. It's hence less close to the horizon at the same time of the day. Less close to the horizon means less atomospheric absorption/scattering responsible for the dull red color, assuming the same weather conditions.
At Full Moon the Moon is at the opposite side of the Sun relative to Earth. Moon is then rising shortly after sunset.
The following is multiple choice question (with options) to answer.
If a day goes by and night falls surprisingly quickly | [
"it is likely freezing",
"summer is just beginning",
"the beaches are opening",
"summer solstice is being celebrated"
] | A | the amount of daylight is least in the winter |
OpenBookQA | OpenBookQA-3709 | everyday-chemistry, food-chemistry, enzymes
Now you suggest using dilute honey in place of pure glucose oxidase (since the former's easy to get). But that would barely work.
The composition of honey depends on multiple factors; type of bee, region, season, etc. But from looking up the composition of various kinds of honey (courtesy: Google), apparently glucose oxidase constitutes a fraction of honey. So diluting honey here would make things worse (lower concentration of glucose oxidase). Obviously, adding concentrated honey is also out of question...since that would alter the flavor of the tofu altogether.
As @airhuff mentioned in the comments below: Use of honey is still an option...but a poor option, nonetheless. Why you ask? Because there are no simple means for one to go about quantifying the glucose oxidase content in some random honey-sample. The process(es) are time-consuming, pricey and hence, (probably) impractical for your needs. Additionally, even if it contains the "right" amount of glucose oxidase, I fear that even dilute honey would still alter the taste of the tofu (there's a reason why honey is the popular epitome for "sweetness").
What can you do now?
1) You can buy glucose oxidase online at Sigma-Aldrich. But if your tofu-making session is a one-time thing (i.e- You don't run a tofu-making factory) then this is a bit impractical.
2) Minimize contact with air! The primary reason the soy milk reeks is because the lipoxygenase is breaking down PUFAs using molecular oxygen. So if you want to limit the enzyme's activity, you must keep contact between the soy milk and air to a minimum.
Some ways you can do this:
a) As soon as your done grinding the soy beans with water, transfer it to an air-tight container (fill it all the way to the brim) until you need it.
b) When you're transferring the soy milk from one vessel to another, be sure to avoid air-bubbles. This answer by @Buttonwood may prove useful in that regard.
The following is multiple choice question (with options) to answer.
Which of these would enjoy the flavor of honey? | [
"Raccoons",
"Leaves",
"Bacteria",
"Flowers"
] | A | animals taste flavors |
OpenBookQA | OpenBookQA-3710 | botany, plant-physiology, plant-anatomy
Title: How do plants grow year after year even though they die? How do plants grow, die, and then grow again? For instance, when my plants die during the winter, how do they grow again next year? Does it have something to do with the root system? Or do they even die? It depends on the type of plant, but basically not all of the plant dies. Plants have evolved a number of strategies for winter* dormancy. These are common ones, but probably not an exhaustive list.
Deciduous trees and bushes simply drop their leaves in the fall, and so may look "dead" to the unskilled eye - though with practice, it's usually easy to distinguish between dead and dormant. Then when the weather warms in the spring, new leaves grow.
Other perennial plants may lose some or all of their top growth, even dying back to ground level, but the roots will be alive, and will start growing when the ground warms.
Still other plants have developed specialized underground structures like bulbs & rhizomes - think daffodils, tulips, irises, and similar. The rest of the plant dies, only to grow again from the bulb when conditions are right.
It's worth noting that most, if not all, of these are used for propagation as well, often naturally, and frequently with a bit of human help. Bulbs and rhizomes multiply: the daffodil bulb you planted a few years ago may now be a dozen bulbs, each of which can be moved to grow new ones. Many perennials can be increased by dividing the root mass into pieces, each of which will become a new plant. And cuttings from many trees & bushes can be induced to form new root systems, and become new plants.
Or summer, dry season, &c. For simplicity, I'll just say "winter".
The following is multiple choice question (with options) to answer.
usually plants die or become dormant after the | [
"lowest solstice",
"naptime",
"a good book",
"lunch"
] | A | usually plants die or become dormant during the winter |
OpenBookQA | OpenBookQA-3711 | the-moon, solar-flare, dust
Title: Any new info about solar flares hitting the Moon added by the LADEE mission? This article from 2011 mentions simulations about the sputtering effect caused by a solar flare hitting the Moon:
"We found that when this massive cloud of plasma strikes the moon, it
acts like a sandblaster and easily removes volatile material from the
surface," said William Farrell, DREAM team lead at NASA Goddard. "The
model predicts 100 to 200 tons of lunar material – the equivalent of
10 dump truck loads – could be stripped off the lunar surface during
the typical 2-day passage of a CME."
The researchers said they were waiting for LADEE to confirm these simulations and add new data, but I didn't find any conclusions on this subject on the mission website. I was interested if this event can create a significant static electricity difference between the 2 sides of the Moon, causing some sort of lightnings on the edges or even a mini-version of a dust storm. You'd probably be most interested in the results of the Lunar Dust EXperiment (LDEX). A 2015 paper states
LDEX data show no evidence for an electrostaticallylofted
dust component at densities greater than a few
per m3
I am assuming the solar flare stuff didn't pan out, otherwise it would be mentioned in the various LDEX summary papers. In addition, the NASA DREAM group site doesn't seem to have anything relevant LADEE results, and they're the ones that brought the subject up in the first place.
The following is multiple choice question (with options) to answer.
the lunar surface contains | [
"aliens",
"snakes",
"bumpless regions",
"trees"
] | C | the moon 's surface contains flat areas |
OpenBookQA | OpenBookQA-3712 | thermodynamics, temperature, water
Title: why does cold water have Translucent visibility? If ice is to formed soon, why ice Does not have Tranparent vision. it becomes translucent because the air that was dissolved in it comes out of solution to form tiny bubbles within the mass of ice.
To avoid this, ice that is intended for use in drinks is frozen in a way that gets rid of the air bubbles. This makes the resulting ice cubes perfectly transparent, which is what people want in their whiskey.
The following is multiple choice question (with options) to answer.
As frozen water decreases more sunlight is | [
"absorbed",
"frozen",
"detected",
"reflected"
] | A | glaciers melting has a negative impact on the glaicial environment |
OpenBookQA | OpenBookQA-3713 | evolution, terminology, natural-selection, computational-model, definitions
On the other hand suppose we have some environment in which there are two anisofit fitness related hereditary material populations. Now if some environmental, or recombinative genetic change inflicts those two populations, that works either in a neutral manner, i.e. causes equal population sizes of those anisofit fitness related hereditary material, or works in an opposite-directional manner, i.e. in a direction that is opposite of the expected direction mentioned above, better be termed as "contra-directional". In this situation even if the size of the populations of those hereditary materials is different (imparting the appearance of a selection) still that difference is not explained by the effect of those anisofit fitness related hereditary material on their fitness in that environment! So this would not be an example of natural selection! It would be an example of an environmental factor that caused a "genetic drift", or of a genetic recombination process that caused a "genetic drift" also.
So we in effect have a struggle between "natural selection" which works in the direction of increasing adaptation with the environment, on one hand, and "random selection" (or sometimes called neutral selection or non-selection) which doesn't necessarily work in the direction of increasing adaptation with the environment.
So in some sense "evolution" is determined by the struggle of those two kinds of mechanism of change.
If random change prevails, then evolution would not necessarily move in the direction of increasing adaptation of living organisms with their environment. While if "natural selection" prevails, then evolution would proceed in the direction of increasing adaptation to the environment. I've mostly skimmed the formalism you introduced, but getting to the 2nd half of your post, the answer is yes, you understood correctly the distinction between natural selection (aka adaptive evolution) and drift (aka neutral evolution), as well as the fact that it's not a given that natural selection would be the predominant effect in arbitrary circumstances. Small population sizes, high rates of mutation, weak genetic repair mechanisms, etc. can all lead to chance being the predominant effect.
The conditions needed for natural selection to be predominant have been investigated in lots and lots of publications. A quick overview and brief list of such publications is found in
Duret, L. (2008) Neutral theory: The null hypothesis of molecular evolution. Nature Education
The following is multiple choice question (with options) to answer.
An adaptation that humans have created through the help of science is | [
"freckles",
"feces",
"eye color",
"flying"
] | D | An example of an adaptation is camel humps |
OpenBookQA | OpenBookQA-3714 | thermodynamics, absorption
When you want to boil water efficiently, you do two things: cover the pot (limit loss due to evaporation) and put the heat inside if you can: for example the submerged heater element in electric kettles. Other forms of boilers also put the heat in the middle of the water (think water heaters for homes) so most of the hot gas gets to give off its energy to the water.
But if you have a flame, the best you can hope to to is transfer all it's internal energy to the water - so when the water is hotter a flame is always less efficient.
Very efficient systems use counter flow - the hot air moves left to right, and the water to be heated right to left: in that way the colder gas meets even colder water so when the gas finally is exhausted it has no heat left. Same principle is used in efficient gas furnace for homes, etc.
The following is multiple choice question (with options) to answer.
What does a stove generate for cooking? | [
"ice",
"scorching temperatures",
"cold",
"freezing"
] | B | a stove generates heat for cooking usually |
OpenBookQA | OpenBookQA-3715 | declination, right-ascension, sunrise, sunset, sidereal-period
is there a right ascension formula I'm missing or is the right ascension of the sun pre-defined on a solstice like the declination is(to a reasonable degree)
plus I had to get the right ascension of of a table which I wont be given in the exam so how does one calculate the right ascension on any given date.
and also one further question why does this only happen at the arctic circle, is there something special about this latitude. You need to intepret the question a bit. By "June 22" they probably mean "Summer Solstice", likewise for "Dec 22". At the solstice the right ascension of the sun is 6hr/18hr exactly.
Also the latitude of the Arctic circle is, by definition, 90 minus declension of sun at solstice. And $\tan(x)\tan(90-x)\equiv 1$
So your expressions for the hour angle simplifies to $h=\arccos(-1)$ (which is 12hr) and adding the right ascension gives exactly 18hr. You'll get 18hr exactly at winter solstice too.
To decode the question you need to realise that "June 22" and "Arctic circle" are codes for "Solstice" and "Latitude of 90 minus axial tilt of Earth", so the trigonometric expression doesn't need to be evaluated by calculator, rather it can be simplified.
The following is multiple choice question (with options) to answer.
the winter solstice is on June 21st in the | [
"upper side of earth",
"only online in blogs",
"on the dark side of the moon",
"lower half of terra"
] | D | the winter solstice is on June 21st in the southern hemisphere |
OpenBookQA | OpenBookQA-3716 | carbohydrates, hydrolysis, taste
Title: Why are polysaccharides not sweet in taste? Polysaccharides are defined as polyhydroxy aldehyde or ketone which on hydrolysis yield many units of monosaccharides.
I got one answer(to my question above) as:
On our tongue, we have things called taste receptors. These receptors are loosely categorised into sweet, sour, bitter and salty. Our sweet-receptors bind to specific types of molecules, namely monosaccharides and disaccharides. Polysaccharides are not as sweet because they do not readily bind to the sweet-receptors on our tongue, as the other smaller molecules do!
My question is that in our body (due to the presence of water),polysaccharides and oligosaccharides are hydrolysed to simpler units of monosaccarides...
So why does the latter respond to the receptors(indicating sweetness) while the former does not(while both yield monosaccarides on hydrolysis)? Well, while indeed polysacharides are metabolised to simpler units, even in mouth (saliva in the mouth can account for 30% of initial starch digestion), it usually doesn't happen fast enough, so full digestion follows later in you digestive system.
You can`t sense the sweetness of polysaccharides as they do not fit the receptors.
The following is multiple choice question (with options) to answer.
glucose causes food to taste | [
"wet",
"like candy",
"dry",
"hot"
] | B | sugar causes food to taste sweet |
OpenBookQA | OpenBookQA-3717 | mountains, geography, paleogeography, isostasy, mountain-building
Title: What were the tallest mountain ranges in Earth's geological past? There have been numerous episodes of mountain building in Earth's geological history, particularly through the super-continent cycle. Many mountains and mountain ranges have been eroded, as mentioned in the similar question Determining the paleoelevation of mountain ranges.
What are believed to be the tallest mountain ranges in Earth's geological past? Additionally, what evidence is there to support these palaeoelevations? Factors determining the maximum possible height of mountains include the rate of uplift versus the rate of erosion[a] and rock strength.
Rock strength is controlled by the type and internal structure of the rock in question. There is some evidence that once mountains extend above the snow line, glacial and periglacial erosion have a stronger control than exhumation/uplift rate (Brozovic et al, 1997; Egholm et al, 2009).
Everest and the Himalaya have reached their maximum possible elevation: the formation of the Tibetan plateau is due to the failure of rocks preventing the maintenance of discrete mountain peaks. The principle of uniformitarianism suggests that - subject to differences in variables discussed by Egholm et al, including crustal composition - the Himalaya and Tibetan plateau are an excellent approximation to the maximum achievable height of mountain ranges. However, identifying which specific palaeoranges were tallest (as opposed to calculating a plausible upper limit on height) is a significantly harder problem to solve.
[a] Though note that the rate of erosion increases as the rate of uplift increases - for more on erosional equilibrium, see e.g. Riebe et al (2000).
The following is multiple choice question (with options) to answer.
If a hilly area that reaches incredible peaks is existing, then what happened long ago was | [
"things were steamed",
"rocks were tiny",
"stones crumpling together",
"plants were eaten"
] | C | the Appalachians were formed by rock folding |
OpenBookQA | OpenBookQA-3718 | That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The total that we have observed the opossums to eat is 5% x 150 + 10% x 120 + 20% x 120 = 43.5 plants.
They eat 5% large, which a corresponding fraction of 5% x 150 / (5% x 150 + 10% x 120 + 20% x 120) = 17%
They eat 10% low for 10% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 28%
They eat 20% hybrid for 20% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 55%.
Checking... yes the total is 100%.
What we see is that the opossums prefer hybrid by far.
Small blueberries are their second choice.
Last edited:
#### anemone
##### MHB POTW Director
Staff member
Hi anemone!
What do you mean by the symbol E?
Anyway, you've found that the opossums eat 45.8% large and 54.2% small for a total of 100%.
But... what happened to the hybrid blueberries?
By the symbol E, I meant the blueberries (all 3 types of them) that are eaten by opossums...
That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The following is multiple choice question (with options) to answer.
Cactus house a great amount of | [
"favorite fishing holes",
"chlorophyll",
"bark",
"pine cones"
] | B | a plant cell contains chloroplasts |
OpenBookQA | OpenBookQA-3719 | forces, free-body-diagram, fluid-statics, buoyancy
If the object falls all the way to the bottom and rests there some buoyancy will be lost, and all of it will be lost if the sides of the object are not tilted in a way to create buoyancy. A tapered object could even undergo negative buoyancy. It often happens with stuck drill pipe.
It is of course possible that some objects cannot support pressure and will collapse. I am assuming we are not talking about those.
The following is multiple choice question (with options) to answer.
if a solid piece stands out in the elements, and reduces in size over time, what might have happened? | [
"it is moving away",
"it has been depressed",
"it has been stolen",
"it has been weathered down"
] | D | sediment is formed by weathering |
OpenBookQA | OpenBookQA-3720 | $\{a_4\}$
$\{a_4,a_1\}$
$\{a_4,a_2\}$
$\{a_4,a_2,a_1\}$
$\{a_4,a_3\}$
$\{a_4,a_3,a_1\}$
$\{a_4,a_3,a_2\}$
$\{a_4,a_3,a_2,a_1\}$
$\{a_5\}$
$\{a_5,a_1\}$
$\{a_5,a_2\}$
$\{a_5,a_2,a_1\}$
$\{a_5,a_3\}$
$\{a_5,a_3,a_1\}$
$\{a_5,a_3,a_2\}$
$\{a_5,a_3,a_2,a_1\}$
$\{a_5,a_4\}$
$\{a_5,a_4,a_1\}$
$\{a_5,a_4,a_2\}$
$\{a_5,a_4,a_2,a_1\}$
$\{a_5,a_4,a_3\}$
$\{a_5,a_4,a_3,a_1\}$
$\{a_5,a_4,a_3,a_2\}$
$\{a_5,a_4,a_3,a_2,a_1\}$
$\{a_6\}$ $\{a_6,a_1\}$
$\{a_6,a_2\}$ $\{a_6,a_2,a_1\}$
The following is multiple choice question (with options) to answer.
A/an __________________ is reusable | [
"liquid soap",
"dish towel",
"band-aid",
"apple"
] | B | something reusable can be used more than once |
OpenBookQA | OpenBookQA-3721 | reproduction
Title: Why are so many species reproducing late this year? Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very young offspring so late in the season. I was always under the impression that the vast majority of animals and fish produced young in the spring (March/April).
For example, we saw tadpoles, fluffy (ie obviously very young) coots and weeny minnows. I would have expected that all of these would have been born/laid a good 3 or 4 months ago, and so would be more mature by now.
Caveat: We didn't do a scientific study, this is just a strong impression we got from days out in north west England. It's hard to say without more information, but one substantial possibility is that you are mistaken that species are reproducing late - that's a problem with anecdotal rather than scientific data!
Additionally, species you mention like the common coot can attempt multiple broods where the season is long enough. Wikipedia specifically mentions Britain:
Eurasian coots normally only have a single brood each year but in some areas such as Britain they will sometimes attempt a second brood
The same could be true for species of frogs/toads and fish, so without knowing specific species it can't be known whether these are species reproducing again or species reproducing late.
The following is multiple choice question (with options) to answer.
An example of reproduction is | [
"sleeping",
"mestrual vessel releasing",
"skipping",
"snacking"
] | B | An example of reproduction is laying eggs |
OpenBookQA | OpenBookQA-3722 | thermodynamics, energy, potential, energy-storage
It is possible to store a current in a superconducting loop, but maintaining the system in a superconducting state requires energy, and as soon as the system makes the transition to non-superconducting the current rapidly decays to heat.
The following is multiple choice question (with options) to answer.
What could be a conductor of energy? | [
"a nickel",
"carrots",
"wood",
"cotton"
] | A | metal is an electrical energy conductor |
OpenBookQA | OpenBookQA-3723 | hygiene, food-chemistry
Dishes and utensils are only susceptible to bacterial growth if there's traces of food on them. Washing is meant to remove traces of food and oil so bacteria can't multiple on them. The conditions must be right for bacteria to multiple. If traces of food were to be completely dry and hardened on a dish and someone ate off it, the likelihood of any bacteria present on it is close to nil. They need moisture to grow. If dishes had no oily food on them, washing and rinsing with very warm water would be sufficient. I've seen people from other cultures wash dishes with traces of food that are soluble in water. They come out perfectly clean. (As an aside, using a tea towel can often spread bacteria when they're not used properly.) Towels top kitchen contamination hazards list
Bacteria can't multiple in oil. For example, ordinary cooking oil doesn't need to be refrigerated although it can go rancid. A cast iron frying pan is properly meant for frying foods only. No watery sauces should be cooked in them. Even "scraping it clean" shouldn't be done with a sharp metal object as it can remove some of the polymerized hardened oil layer.
I have several cast iron pans that I don't wash. I wipe them out after each use, then I add a little oil nd roughly a teaspoon of salt. With a paper towel, I rub at any bits of stuck on food. If done within a few hours of being used, it effectively removes any food traces, leaving a smooth surface. I usually rinse off the salt in warm water, dry it and then apply a very thin film of oil. I've been cooking in cast iron pans for decades and have never gotten sick or had mild food poisoning (what many people call a 'stomach flu').
Cast iron pans with a layer of proper seasoning and treated like this will definitely not cause sickness. It can't support bacterial growth and as @jeanquilt mentions, the pan gets very hot - enough to blister your skin if you touch them with a bare hand.
The following is multiple choice question (with options) to answer.
Eight month old tuna salad will make a person | [
"hairy",
"rich",
"clean",
"sick"
] | D | food spoiling has a negative impact on the health of the animal that eats that food |
OpenBookQA | OpenBookQA-3724 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
if an organism makes food for itself then that organism needs to | [
"take naps",
"swim fast",
"synthesize itsenergy",
"ride bicycles"
] | C | if an organism makes food for itself then that organism does not need to eat other organisms |
OpenBookQA | OpenBookQA-3725 | human-biology, microbiology, literature
90% of these specimens were deemed "No Growth" by the standard urine culture technique, highlighting its limitations.
The last phrase "highlighting its limitations" is an interesting one. It appears to me to be yet to be proven that this is a clinically meaningful "limitation" of such assays. Without attempting to refute these data — fortunately this question doesn't require me to do so — I will note that the two linked studies aimed to show that people with overactive bladder are characterized by increased urinary flora. The explicitly stated hypothesis is that this may contribute to symptoms. Even in this study demonstrating the existence of such a micro-biome even in normal people, then, it is understood as a potentially pathologic state.
The reason this "mantra persists", then, is that it remains true for clinical purposes. In contrast to most (all?) other bodily discharges, urine is not packed with bacteria, and the commonly used assays reflect this fact. Medicine and laboratory science have different "modes of discourse", each calibrated to convey levels of precision that are appropriate to the outcomes of interest.
Notes
1. In American English at least, that adverb is ambiguous, meaning either "for practical purposes" or (idiomatically) "almost". Both senses are intended here.
2. Of course, there are plenty of data in various populations demonstrating that some substantial minority of urinalyses among asymptomatic people return positive, "proving" that we shouldn't be checking them (amen!). But this is not the point. The gestalt remains: normal = negative.
3. The nitrite parameter in particular is not especially sensitive. It is, however, quite specific (92-100%), meaning it reliably returns negative in people without infection. (See review, below.) Of course, negative nitrites does not mean sterile in the sense that the OP has used it; see "modes of discourse", above.
Reference
Simerville JA, et al. Urinalysis: A Comprehensive Review. Am Fam Physician. 2005 Mar;71(6):1153-1162.
The following is multiple choice question (with options) to answer.
Slurping down your urine shows you're | [
"bed-wetting",
"recycling",
"menstruating",
"preserving wetlands"
] | B | An example of conservation is avoiding waste |
OpenBookQA | OpenBookQA-3726 | optics, visible-light, vision, absorption, laboratory-safety
Title: Why are UV protective eyeware Orange? Many industrial processes use uv as a curing agent. When one uses such a process, one must protect one's eyes from the radiation. Most uv protective gear I have seen is tinted orange?
Does this orange color come from the actual uv blocking chemicals, or is that color added for some user related reason (like being confident you picked up the right glasses) For typical laser goggles the color of lens is the color of light that is transmitted through the lens. Thus if the lens is red, it will not protect you from laser beams that are in the red portion of the spectrum.
The color you are looking for will be, in some sense, the complementary color; since red-orange-pink are far from blue-violet-ultraviolet, these are the lens colors you would expect to work for UV light.
I have often worked with high power, class 3B and class 4, UV lasers, from 405 nm, which is UVA, down to 264 nm, which is beyond the UVB. The typical goggles which cover these ranges are orange to pink.
Your hypothesis is correct: the color comes from an absorptive dye which is incorporated into the plastic or glass.
It is also possible to apply multi-layer optical coatings to the lenses of spectacles which will preferentially reflect in the UV; this is a more expensive approach (hence dyes), and relies on destructive interference for the transmitted waves. The goal is to make make it transparent in the visible spectrum.
The following is multiple choice question (with options) to answer.
safety goggles are used for protecting the eyes during | [
"sleeping",
"persuits of knowledge",
"dancing",
"singing"
] | B | safety goggles are used for protecting the eyes during experiments |
OpenBookQA | OpenBookQA-3727 | human-biology, zoology, pathology
Title: Do humans contract more physical sicknesses and diseases than animals do? I wondered: If I get into the library and look into the medical section it is evident that there are thousands and thousands of different human physical diseases. But if I look into the section of animal diseases it is by no means as large as the human section.
But humans are by no means the only beings with extraordinarily cell complexity. Many other animals have an equal amount of cell complexity. So shouldn't other animals have an comparative equal amount of diseases ?
Naturally as humans we are much more interested in human physiology which would explain the discrepancy. But is there any evidence that animals, especially mammals, have not an equal amount of (still unknown) different diseases ?
Remark:
While a bit similar, this is not this question:
Why do humans seem so much more prone to disease than animals?
I am asking about the quantity of diseases, not if humans are especially prone for diseases.
ADDENDUM:
The difference between the questions is like
"Is building A more prone to fall in natural catastrophes than other buildings because it seems like it ?"
and
"How many faults have building A in comparison to other buildings ?"
A correct answer to the first question is: "We made a statistical comparison and building A is more/less/equal prone to fall in a natural catastrophe. The impression is wrong/right."
A correct answer to the second question is: "Building A has in fact a mean approximately 13 000 faults while other buildings have only 5400 faults. But the reason can be that the other building are inspected with less care." Or "No, they both have very likely something like 9000 faults".
The following is multiple choice question (with options) to answer.
natural disasters can cause animals to | [
"deep fry",
"dance",
"trek",
"nap"
] | C | natural disasters can cause animals to leave an environment |
OpenBookQA | OpenBookQA-3728 | special-relativity, energy, mass
Yes, it would. Unless said object has no mass (photons etc.)
Well yes, anything in its path would be in trouble, but then again at those speeds a stray hydrogen atom would put a huge hole in your ship. (That's why in Star Trek, the spaceships are always equipped with Bussard Collectors to "sweep up" threatening matter before it could harm the ships)
I believe that is entirely dependent on the mass of the spaceship, and the fraction of C it is traveling at. (If it has enough velocity or mass, then yes. It would.)
As stated in another answer, whether or not something has enough mass to be a black hole is entirely dependent on the rest mass, not the relativistic mass.
Hope this helps :-).
Edit: I should also say that if you are not accelerating an object to an appreciable percent of C, than the increase in mass will be negligible. For example: (from Wikipedia)
Raising the temperature of an object (increasing its heat energy) increases its mass. For example, consider the world's primary mass standard for the kilogram, made of platinum/iridium. If its temperature is allowed to change by 1 °C, its mass will change by 1.5 picograms (1 pg = 1×10−12 g).
1.5 pg is really, really, really tiny. (0.0000000000015g. A baseball is about 142g.)
The following is multiple choice question (with options) to answer.
if you increase the mass of a celestial body, it will | [
"lose rotation",
"lose gravitational force",
"gain gravitational force",
"maintain it's gravity"
] | C | as mass of a celestial body increases , the force of gravity on that planet will increase |
OpenBookQA | OpenBookQA-3729 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is true? | [
"glaciers make depressions that water can pool in",
"lions hunt glaciers in the wild",
"glaciers are generally high temperature objects",
"glaciers can change directions rapidly for speed"
] | A | a glacier causes mechanical weathering |
OpenBookQA | OpenBookQA-3730 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
When would most people wear shorts? | [
"a ski trip",
"a cold night",
"a cold morning",
"a noon picnic"
] | D | as temperature during the day increases , the temperature in an environment will increase |
OpenBookQA | OpenBookQA-3731 | 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.
Where do bees get nutrition? | [
"seeds from a farmer's field",
"from the leaves of trees",
"the local grocery store",
"a powdery substance found in the reproductive parts of plants"
] | D | bees eat pollen |
OpenBookQA | OpenBookQA-3732 | species-identification, botany
Title: Succulent weed identification There is a succulent-looking weed growing in a crack in my driveway. What is it?
Conditions: Dry, full sun, asphalt & gravel, no competition.
Date: 2018-07-16
Location: Toronto, Ontario, Canada
Size: 40cm x 40cm x 2cm This is Common purslane, Portulaca oleracea. It is used in salads, although it contains oxalic acid and there are poisenous plants resembling Purslane, see comment below.
https://en.m.wikipedia.org/wiki/Portulaca_oleracea
The following is multiple choice question (with options) to answer.
The sidewalk next to a house having a crack in it and having vegetation growing from it is considered? | [
"insects",
"weathering",
"erosion",
"lava"
] | B | soil erosion is when wind move soil from environments |
OpenBookQA | OpenBookQA-3733 | virus
Assuming that you're not going splunking in bat inhabited caves in West Africa, it's safe to assume that what we are worried about is human to human transmission through infectious fluids. Ebola actual isn't that stable in water, so just soaking a surface in water and a little oil might help you out (if you don't have bleach handy). I want to be clear that I'm not recommending this, in reality you should just avoid contaminated objects. I think that we have clearly established that what we're really concerned about is infectious bodily fluid.
This leads me to the wonderful note by Jose Martin-Moreno titled "Is respiratory protection appropriate in the Ebola response?" I don't think I can express the problem better than he can, so hopefully I will be allowed a substantial quote:
This transmission [of ebola] occurs via close family contact or in
health-care settings, particularly when placing orotracheal intubation
or when caring for a patient who is vomiting or bleeding. Ebola is
rarely transmitted via an airborne route. Although these routes of
transmission are well known, most agencies, including governmental
agencies responsible for repatriating western patients, apply
infection-control measures appropriate for airborne diseases.
Excessive precautions could offer reassurance to those responding to
Ebola, yet complete respiratory protection is expensive,
uncomfortable, and unaffordable for countries that are the most
affected. Worse, such an approach suggests that the only defence is
individual protective equipment, which is inaccessible to the general
population. Moreover, the image of workers with spectacular protective
clothing might contribute to the panic in some communities. If this
leads people to flee affected areas it could increase the spread of
infection.
The following is multiple choice question (with options) to answer.
Dozens in your workplace are sick with the flu. To protect yourself, you might | [
"inject yourself with deactivated elements of the illness",
"inject yourself with a smallpox vaccine",
"Inject yourself with a healthy person's blood",
"inject yourself with morphine"
] | A | vaccines can help prevent illness |
OpenBookQA | OpenBookQA-3734 | java, reinventing-the-wheel, console, unix
With clothes the new are best, with friends the old are best.
He is truly wise who gains wisdom from another's mishap.
Beware of a dark-haired man with a loud tie.
Today is the last day of your life so far.
Flee at once, all is discovered.
Man who falls in vat of molten optical glass makes spectacle of self.
Go directly to jail. Do not pass Go, do not collect $200.
For a good time, call 8367-3100.
Those who can, do; those who can't, simulate.
Those who can, do; those who can't, write. Those who can't write work for the Bell Labs Record.
God does not play dice.
This fortune is inoperative. Please try another.
Laugh, and the world ignores you. Crying doesn't help either.
No amount of genius can overcome a preoccupation with detail.
You will feel hungry again in another hour.
You now have Asian Flu.
God made the integers; all else is the work of Man.
Disk crisis, please clean up!
You auto buy now.
Many are called, few are chosen. Fewer still get to do the choosing.
Try the Moo Shu Pork. It is especially good today.
Many are cold, but few are frozen.
The early worm gets the bird.
He who hesitates is sometimes saved.
Time is nature's way of making sure that everything doesn't happen at once.
The future isn't what it used to be. (It never was.)
Can't open /usr/lib/fortunes.
If God had wanted you to go around nude, He would have given you bigger hands.
It is better to have loved and lost than just to have lost.
A journey of a thousand miles begins with a cash advance from Sam.
Disk crunch - please clean up.
Center meeting at 4pm in 2C-543
I will never lie to you.
Spock: We suffered 23 casualties in that attack, Captain.
Your computer account is overdrawn. Please reauthorize.
1 bulls, 3 cows
It's hard to get ivory in Africa, but in Alabama the Tuscaloosa.
Waste not, get your budget cut next year.
Old MacDonald had an agricultural real estate tax abatement.
Snow Day - stay home.
Save gas, don't eat beans.
The following is multiple choice question (with options) to answer.
If your grandma sends you out in the yard to get the weeds out of the garden she means to | [
"water the weeds thoroughly",
"rip them out of the soil",
"fertilize and till the weeds",
"ask them to leave the yard"
] | B | if a weed is pulled then that weed is destroyed |
OpenBookQA | OpenBookQA-3735 | photosynthesis
Title: Photosynthesis in oxygen free enviornment If a plant is grown in an oxygen free enviornment would it live longer in light or darkness?
It is evident that oxygen would compete with carbon dioxide during various processes like competing with carbon dioxide for reducing power, also oxygen quenches the excited electron of chlorophyll etc.
But all these effects to me don't give any sense of the extent of oxygen on these reactions. What does the absense of oxygen have on the system? Except ofcourse the plant not being able to respire properly. If that "environment" is a closed vessel or bell-jar; certainly the plant would survive in light (when it simultaneously perform respiration and photosynthesis), and in darkness (when it can perform only the respiration) it would survive upto certain time due to the oxygen it accumulated. But should die at prolonged darkness when the plant would finish all the oxygen.
(as suggested by Priestley's classic 1870 experiment * there was enough oxygen to keep a mouse for certain time)
(image link)
However, if we look the effect of various concentration of O2 on photosynthesis rate without altering the CO2 concentration; yes the photosynthesis rate get affected; one known effect is called Warburg effect or Inhibition of photosynthesis by O2.
In this effect, photosynthesis rate only decrease if O2 concentration is increased. And in vice-versa, with O2 concentration decrease, photosynthesis rate only increase. (source: this, this, this and this)
This take place due to mainly 2 causes: 1. O2 work in competitive way with CO2 for binding with the enzyme RuBisCO, the key enzyme for CO2 fixation in plants. 2. And that induces photorespiration (in C3 plants). (Wikipedia shows reference to here). (However this old paper also tells other hypotheses)
The following is multiple choice question (with options) to answer.
Stopping the photosynthesis process would require | [
"providing a plant with a oxygen rich environment",
"placing a plant in total darkness 24/7",
"watering a plant regularly",
"putting a plant in a sunny area"
] | B | a leaf absorbs sunlight to perform photosynthesis |
OpenBookQA | OpenBookQA-3736 | zoology, mathematical-models, software, imaging
Title: What would it take to recognize a deer by its photo? I am trying to recognize a deer by its antlers or any other means.
Elaborating:
I was hoping to use their antlers to recognize them but I have heard that most deers shed their antlers every year so it would be difficult to recognize it from the last year's photo unless these antlers retain the same pattern every year.
If not the antlers, what other characteristics should I be looking for?
Is there any software that can help me in recognizing a deer? There is a lot of variation in how and when deer shed their antlers. In most arctic and temperate-zone species, antler growth and shedding is annual, and is controlled by the length of daylight. In tropical species, antlers may be shed at any time of year, and in some species such as the sambar, antlers last several years. Some equatorial deer never shed their antlers.
The horns change every year and, especially, increase the number of branches (and consequently, change their shape). You can't recognize them by antlers, but by other features, such as color of the hair or the lineaments. Like us, animals have individual morphological differences that are recognizable and listable.
Biologists specializing in studies of particular animal species not only take photos, but also make drawings and write descriptions of behavior, to identify individuals within herds.
An optical examination, however, of the subject through drawings and photos (and if possible, direct observation), is more useful than a PC program. This involves identifying particular similarities and equalities that are not "identical". This is possible to do visually on a large (but limited) number of specimens. The human eye is the best computer.
The following is multiple choice question (with options) to answer.
An hunter that wants to be undetected seeking out deer in the forest might | [
"be dressed bushy green and brown attire",
"cover themselves in tree sap",
"be dressed in arctic camouflage",
"change their facial expression"
] | A | camouflage can be used for hunting for prey |
OpenBookQA | OpenBookQA-3737 | earth, the-sun
Title: Latest sunrise/earliest sunset out of phase with solstice? Everybody knows that the shortest and longest days of the year occur on the solstices. However, examination of sunrise/sunset tables shows that the maxima and minima of sunrise/sunset times are offset from the solstices by about 10 days.
According to timeanddate.com for my location (Portland, OR), for the winter solstice, the earliest sunset is about December 10 (16:27), and the latest sunrise is around January 1 (07:51).
This is counterintuitive... what's the explanation? The point here is that sunrise and sunset does not only move towards or away from noon, but noon itself moves around 12:00. There is a difference between "civil time" (the one counted by wall clocks) and "solar time" (the one marked by sun clocks). This difference is called the "Equation of Time" and its geometrical shape is called the Analema.
So in order to have the earliest sunset you need a combination of both a short day and a noon moved before 12:00. Same reasoning for latest sunrise.
You can see more about the Equation of Time on Wikipedia: http://en.wikipedia.org/wiki/Equation_of_time
The following is multiple choice question (with options) to answer.
The winter solstice is the shortest day in the northern | [
"sky",
"parts of Australia",
"globes top half",
"counties of Tasmania"
] | C | the amount of daylight is least on the winter solstice |
OpenBookQA | OpenBookQA-3738 | 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 way for an octopus to evade predators is to | [
"befriend the predator",
"emulate a rock",
"swim around",
"bury itself underground"
] | B | avoiding predators has a positive impact on prey 's ability to reproduce |
OpenBookQA | OpenBookQA-3739 | star, galaxy, history, definition, stellar-structure
Title: Metallicity of Celestial Objects: Why "Metal = Non-metal"? Metallicity of objects refers to the amount of chemical elements present in it other than Hydrogen and Helium.
Note: The other elements may or may not be actual metals in the true sense of their defintion.
The following is multiple choice question (with options) to answer.
Metal is sometimes what? | [
"wooden",
"salty",
"polar opposite",
"wind"
] | C | metal is sometimes magnetic |
OpenBookQA | OpenBookQA-3740 | genetics, evolution
in a dioecious species (i.e., one with two sexes), cannibalism means a 50% chance of eating a potential mate and losing the opportunity to pass on your genes
diseases are more likely to transfer between species the more closely related they are. If you are a cannibal you are eating a species with a 99% similarity to you and are more likely to get diseases or parasites. Like kuru/mad cow/chronic wasting disease.
it precludes social behavior and all its benefits. Why engage in mutually profitable behavior when you can just eat those around you? This is thought to be one reason why pack-hunting is rare in some groups of vertebrates like monitor lizards.
on a broad-scale evolutionary perspective, cannibalism means removing members of your own population from the gene pool. It may be good for the individual but it's bad for the species as whole
cannibalism means you are feeding on an animal that is potentially your own size. That's a bad strategy in general. Most cannibalism in nature tends to be adults eating infants or adults scavenging carrion of their own species. By contrast predators are normally larger than their prey, with a few exceptions like pack-hunting wolves and lions.
The following is multiple choice question (with options) to answer.
hunting means humans stalk and murder animals in | [
"space",
"bathrooms",
"the sahara",
"television"
] | C | hunting means humans kill animals in the wild |
OpenBookQA | OpenBookQA-3741 | thermodynamics, climate-science
Title: Where does all the heat go during winter? I do not understand where actually the heat in our surroundings go during the winter season. Is it radiated out into space? I know it cannot coz global warming would not be a issue then. It might get absorbed but where? I tried figuring it myself but couldn't please help.
Where does all the heat go during winter?
There is less energy coming from the sun in the form of electromagnetic radiation impinging on the land during winter.
Depending on the latitude, in regions where there is winter , the difference is large.
The closer to the equator the smaller the effect of "winter".
So it is not where the energy goes, but why it does not fall , and this is explained to first order by the inclination and the distance to the sun during the orbit of the earth.
In general , a body in space radiates energy away the rate depending on various conditions, like green house gases, cloud cover, convection , albedo ...the numbers change . It is the continuous radiation from the sun that keeps replenishing the energy so that the earth does not freeze. During winter at high lattitutes , less energy comes and cold settles.
The following is multiple choice question (with options) to answer.
January is during the winter in what location? | [
"Cape Town",
"Melbourne",
"Caracas",
"Rio de Janeiro"
] | C | January is during the winter in the northern hemisphere |
OpenBookQA | OpenBookQA-3742 | botany, species-identification
Title: Plant identification? Can anyone identify the plant below? It's in a backyard in Pennsylvania, and the photo was taken today. Those flowers don't come from the same plant as that big leaf in the front do they? Cant help you with the leaves, but the flower looks like a daylily. source: I know nothing about plants, but happen to have a mom who got a degree in horticulture :)
The following is multiple choice question (with options) to answer.
Which is likely to have come from the same supplier that the florist gets their product from? | [
"a laptop computer",
"a human",
"a steak",
"a durian"
] | D | some flowers become fruits |
OpenBookQA | OpenBookQA-3743 | morphology, dinosaurs
Title: Based on morphology alone, what type of claw does the Tyrannosaur have? I understand that the exact use of Tyrannosaur Rex's claw is a mystery, or at least debated. I also understand that claws can be used for a variety of different purposes, selective pressure adapts their morphological to be better optimized for certain tasks. Some are used for hunting and killing, like large cats' claws, some are used for digging, like bear's claws, while others are used for climbing, like squirrel's claws.
My question is, all other clues and bits of information about if and how T. Rex might have used its arms, what 'type' of claws did it possess? I'm not asking, in this question, about its arm, the arm's musculature, its mouth or jaw, or about any of the rest of the animal. Based on the morphology of the claw alone, and comparing it to known uses of similarly shaped claws, what types of tasks were the claws geared towards? unfortunately they have fairly generic claws, they are not specialized enough to point to a use. They are curved enough to be used to grasp something but that is true for their ancestral line too so there is no sign of a specific directional selection.
The following is multiple choice question (with options) to answer.
An eagle will use their claws to catch which of the following? | [
"nuts",
"elephant",
"bear",
"mouse"
] | D | claws are used to catch prey by some predators |
OpenBookQA | OpenBookQA-3744 | homework-and-exercises, newtonian-mechanics, friction, rotational-kinematics
But, yes, to hit the nail one last time : There is a discrete behavior shift of the frictional force in the problem. If $\mu < \mu_c$, the frictional force is given by $(3)$ and if $\mu > \mu_c$, the frictional force is given by $(1)$.
The following is multiple choice question (with options) to answer.
Friction might be | [
"Breathing",
"rubbing knees",
"Running",
"Rainbows"
] | B | friction occurs when two object 's surfaces move against each other |
OpenBookQA | OpenBookQA-3745 | observational-astronomy, telescope, amateur-observing, optics, deep-sky-observing
Use the brightest stars on your journey to guide your way. Look for shapes: triangles of stars of a similar brightness make great signposts.
If you find that you can see more stars in the eyepiece than the star map is showing you, then you might want to change to one of the other applications. SkEye is free and has a limited catalogue. The other two are not free but have more extensive catalogues.
A great desktop application for this is KStars: it has a star hopping tool which will generate set of instructions, given a start point, and end point, and an eyepiece.
I find star hopping to be a fun way to hunt down targets in the sky. For me it makes the sense of discovery even sweeter. Other people find it dull and would rather use a Go-To mount to do the work for them.
Give it a try and find out which type of person you are - either way is perfectly valid :-)
Filters
In a comment, D.Halsey suggests using a light pollution filter. Unfortunately these are less useful than they were. These days many cities have 'upgraded' to LED lighting, which has the unfortunate side-effect of casting light which covers the full visible spectrum. Light pollution filters worked by filtering out the yellow light given off by the old sodium street lights. Against modern LED lights they don't do very much. If you're fortunate then you might live in an area which hasn't yet changed the street lighting over from sodium to LED - in which case go ahead with the light pollution filter!
Filters which do work - on certain nebulae at least - are the O-III (doubly ionised oxygen) and Ha (hydrogen alpha) filters, or one of the several "nebula filters" which allow both of these bands through.
They don't make the objects brighter - they work by making everything else darker. But they do work. I've seen several nebulae from the city which were impossible to see without them.
Just bear in mind that, because they work by dimming everything except the nebula, they're best used with your lowest power eyepiece: the one that gives the biggest exit pupil, and therefore the brightest view.
Aperture and/or darker skies
The following is multiple choice question (with options) to answer.
Sailors guided themselves with the night sky using a | [
"the sun",
"the moon",
"never moving star",
"light houses"
] | C | the North Star does not move in the sky in the Northern Hemisphere each night |
OpenBookQA | OpenBookQA-3746 | On continuous variables, it would be perfectly plausible to observe an interim value.
But even then, there is a gray area. If you consider the classic 'iris' data set. The variables are continuous. They are lengths of flower petals, so it is plausible for a flower to have any length in-between. But for many analyses, you will get artifacts from the discrete resolution of the input data, which has 0.1 mm or so as step size. This causes problems e.g. with Single-Link clustering. But this is IMHO a different kis0nd of discreteness: the values in-between make sense, it is only our input data that has a bad resolution.
The following is multiple choice question (with options) to answer.
If you want to study a flower closely, use | [
"an enlarger",
"a fork",
"a mirror",
"a telescope"
] | A | microscope is used to see small things by making them appear bigger |
OpenBookQA | OpenBookQA-3747 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
A person in the tundra without a clothing will | [
"fly",
"shiver",
"experience heatstroke",
"undress"
] | B | shivering is when an animal creates heat by shaking to keep the body warm |
OpenBookQA | OpenBookQA-3748 | meteorology, climate-change, gas, pollution
If you are interested in Greenhouse Gases (e.g. methane, carbon dioxide, CFCs, nitrous oxide), the EPA has a separate site for those emissions since they are not part of the same regulatory framework http://www.epa.gov/climatechange/ghgemissions/ . Greenhouse gases typically do not cause adverse health effects for plants or animals on land. However, they have long-term radiative effects (e.g. the greenhouse effect) because they stay in the atmosphere for many years and trap infrared light. These long-term radiative effects are what can change climate and consequently land cover. Furthermore, most of the excess carbon is absorbed by the ocean, which creates carbonic acid. Increased acidity of the ocean causes severe problems for marine ecosystems.
The EPA states that in 2012 the CO2 equivalent GHG emissions for the USA by sector was:
The following is multiple choice question (with options) to answer.
Which is bad for the environment? | [
"recycling old goods",
"using a generator",
"protecting nature",
"eating food"
] | B | burning gasoline is a source of pollution |
OpenBookQA | OpenBookQA-3749 | Hey, thanks for your help guys. For a minute there, I thought that this theoretical person could not safely expect to live to be 82 years old.
9. Jun 16, 2012
### SW VandeCarr
In fact, on a purely probabilistic basis, for any finite time no matter how large, there is a non zero probability that a person would survive that long. So for a sufficiently large population, there would be a theoretic person that would live 100,000 years. This, of course, has no basis in biology.
In terms of the probability of being murdered, the model would not hold for the 100,000 year old person. In terms of the model, probably the best one can do is assume the proportion of causes of death would be constant. The calculation above needs to be corrected for overall survival in terms of death from any cause.
Last edited: Jun 16, 2012
10. Jun 16, 2012
### viraltux
Interesting... but 0.37% is not that small percentage, don't you think? That means, roughly speaking, that a community of around 300 persons can expect that one of them will be murdered.
If you consider that the number of people we know plus acquaintances can easily be around 300 persons that would mean that most 82 year old persons know of someone in their circles who has been murdered. Mmm... that might be an interesting survey.
11. Jun 16, 2012
### SW VandeCarr
As I said in my previous post, this is a misapplication of statistics. You have to consider survival in terms of all cause death. If you just consider the murder rate, then at some point nearly everyone gets murdered.
12. Jun 16, 2012
### moonman239
I know that.
This person will not die until he reaches age 82, if he is not murdered. As mentioned before, this person has a 68% chance of living to be 82.
13. Jun 16, 2012
### D H
Staff Emeritus
The probability of living to 82 per this problem is 99.63%, not 68%. You missed the decimal point on the 0.37%.
14. Jun 16, 2012
### SW VandeCarr
The following is multiple choice question (with options) to answer.
A thing that avoids all harm for its entire life will most likely avoid ever experiencing | [
"having a warm shelter",
"drinking plenty of water",
"being given a meal",
"being set on fire"
] | D | fire causes harm to living things |
OpenBookQA | OpenBookQA-3750 | 1. all chicks peck to the left. 0% of chicks are unpecked.
2. all chicks peck to the right. 0% of chicks are unpecked.
3. all chicks, divided in pairs, peck each other, 0% of chicks are unpecked.
4. chicks are divided in groups of 4, where the pair in the middle pecks each other, while chicks on the edge peck this pair in the middle. 50% of chicks are unpecked.
There are however other possible probability distributions. Two new patterns emerge from this.
1. chicks are divided into groups of 3, where a pair of chicks pecks each other and one chick from this pair is double pecked by a chick on the LEFT. This chick on the left is unpecked which makes a total of 33%. The last, 100th chick can peck randomly left or right but remains unpecked itself as in example 4). This gives 34 unpecked chicks.
2. chicks are divided into groups of 3, where a pair of chicks pecks each other and one chick from this pair is double pecked by a chick on the RIGHT. The last, 100th chick can peck randomly left or right but remains unpecked itself as in example 4). This gives 34 unpecked chicks.
A mixture of all those sets of outcomes are, of course, also possible. Now we can calculate the median of these 6 possible outcomes: (0+0+0+50+34+34)/6=19.666 somewhat lower than the original solution.
The following is multiple choice question (with options) to answer.
birds lay | [
"rocks",
"clouds",
"trees",
"calcium life pods"
] | D | birds lay eggs |
OpenBookQA | OpenBookQA-3751 | thermodynamics, temperature
Title: Non uniform freezing of lakes Here's a problem from my physics textbook:
Why do lakes freeze first at the surface?
I'm not sure why this should happen, and my guess is that the only reason for this could be the temperature distribution with depth, inside water bodies. You need to know that water at $4^{\circ}$C achieve its highest density. So naturally, water at $4^{\circ}$C will tend to move to the bottom of the lake as it is heavier. When the temperature is cool enough to freeze the lake, eventually there will be some layer of ice forming at the surface but there is still liquid water below the ice layer. The ice also works as an insulation to keep the water below it from freezing to ice completely. Also, ice has a lower density than water so any ice forming will float to the surface. There are other factor like Earth's internal heating that constantly maintaining the water at the bottom of lake from freezing.
The following is multiple choice question (with options) to answer.
You can eventually obtain water from a lake even if it's | [
"frozen",
"gone",
"evaporated",
"dry"
] | A | a body of water is a source of water |
OpenBookQA | OpenBookQA-3752 | observational-astronomy, history, naming
Title: What is the brightest nameless star? Bright stars in the night sky traditionally have their own proper names, like "Sirus" or "Canopus".
Most stars don't have names, but instead catalogue identifiers, like the Bayer designation, Flamsteed number, Hipparcos id, etc. Those are not proper names.
What is the brightest star to not have a name?
Some findings and qualifiers, found through initial research:
The IAU has a Working Group on Star Names, with some 449 approved names, but this is still rather incomplete and does not reflect the full body of star names that are in regular use. "Official" is not a requirement for names to exist!
Another collection I found is the NASA technical memorandum 33-50 from 1971 containing 537 star names, by necessity including names not on the IAU list. Cited sources: "Becvar, A. , Atlas of the Heavens — II Catalogue 1950.0. Sky
Publishing Corp. , Cambridge, Mass. , 1964.", "Smithsonian Astrophysical Observatory Star Atlas of Reference
Stars and Nonstellar Objects. The M. I. T. Press, Cambridge,
Mass. , 1969.", "Allen, R. H. , Star Names, Their Lore and Meaning. Dover
Publications, Inc. , New York, 1963."
Names need only apply to naked eye inseparable systems as a whole. For instance, Capella B is one of the brightest stars in the sky, and does not have it's own name, but is visually indistinguishable from Capella A, and would thus be covered under the name "Capella".
The brightest star that is missing from lists with some regularity is Gamma Velorum, but this has the name "Regor" in common use. It's not an old name, merely half a decade and coined by the Apollo 1 astronauts. All names are ultimately "just made up by someone",the important part is whether other continue to use the name. A more traditional Arabic name is "Suhail al Muhlif", even though the "Suhail" name itself is rather ambiguous this would also count as a name.
Epsilon Centauri is called "Birdun" and Alpha Lupi is called "Men", both missing from many lists.
The following is multiple choice question (with options) to answer.
Galileo dismissed what as a mere star? | [
"Neptune",
"Venus",
"Saturn",
"the moon"
] | A | Galileo Galilei made improvements to the telescope to make better observations of celestial bodies |
OpenBookQA | OpenBookQA-3753 | aerodynamics
Title: How do eagles fly slowly for a long time? Eagles fly slowly for a long time.
Many other species fly faster and move their wings faster. But eagles keep their wings steady, and move only their tail.
How do they move slowly in the air, without falling down?
Can this eagle flying technique be used in aviation? How does they move slowly in air, without falling down?
One possibility is soaring using a ridge lift - typically a situation when the wind is approx. perpendicular to a mountain ridge. The air is lifted at the front side of the ridge and an eagle can soar in the lifting air stream. This can also work without the wind,
Which is a situation of thermal flying. Typically, the ground is heated by the Sun, the air layer just above the ground is heated by conduction and at some moment it forms a kind of bubble that starts to rise. This bubble is usually long, resembling a column and lasts until the warm air is depleted. The situation can repeat (this behavior is called an interval). If a ridge is oriented south, then the Sun can create a thermal wind (intervals) that enables a bird to soar.
Can we use eagle's flying technic for flights? Yes, however, man will never be that good.
soaring: https://www.youtube.com/watch?v=63qJn9HrB7E
thermal flight: https://www.youtube.com/watch?v=KXqTCM0-zXQ
Edit: Just for completness - there exists also a wave soaring, that is reachable for gliders and maybe for hangliders, probably not possible for birds and paragliders - see pictures here : http://www.ssa.org/GliderLiftSources
The following is multiple choice question (with options) to answer.
Some Eagles might even consume | [
"Love",
"Emotions",
"Sloths",
"Astroids"
] | C | eagles eat rabbits |
OpenBookQA | OpenBookQA-3754 | python, beginner, raspberry-pi
textin = tempfilein.read()
tempfilein.close()
# Jump to the right position in the sensor file, convert the string to a number, put the decimal point in
secondlinein = textin.split("\n")[1]
temperaturedatain = secondlinein.split(" ")[9]
temperaturein = float(temperaturedatain[2:])
temperaturein = temperaturein / 1000
# print temperaturein
# The outside sensor
tempfileout = open("/sys/bus/w1/devices/" + TempSensorOutside + "/w1_slave")
textout = tempfileout.read()
tempfileout.close()
# Jump to the right position in the sensor file, convert the string to a number, put the decimal point in
secondlineout = textout.split("\n")[1]
temperaturedataout = secondlineout.split(" ")[9]
temperatureout = float(temperaturedataout[2:])
temperatureout = temperatureout / 1000
# print temperatureout
lcd = CharLCD()
# Print the data onto the display.
lcd.clear()
lcd.write_string(time.strftime("%d.%m.%Y %H:%M"))
lcd.cursor_pos = (1, 0)
#lcd.write_string(str(City) + ' ')
lcd.write_string('Innen: '+ str(temperaturein) + ' Grad')
lcd.cursor_pos = (2, 0)
lcd.write_string('Aussen: '+ str(temperatureout) + ' Grad')
lcd.cursor_pos = (3, 0)
lcd.write_string(Weathertext)
The following is multiple choice question (with options) to answer.
A good place to use a thermometer is | [
"your butt",
"a radio",
"a wall socket",
"a bookbag"
] | A | a thermometer is used to measure temperature |
OpenBookQA | OpenBookQA-3755 | the-moon, solar-flare, dust
Title: Any new info about solar flares hitting the Moon added by the LADEE mission? This article from 2011 mentions simulations about the sputtering effect caused by a solar flare hitting the Moon:
"We found that when this massive cloud of plasma strikes the moon, it
acts like a sandblaster and easily removes volatile material from the
surface," said William Farrell, DREAM team lead at NASA Goddard. "The
model predicts 100 to 200 tons of lunar material – the equivalent of
10 dump truck loads – could be stripped off the lunar surface during
the typical 2-day passage of a CME."
The researchers said they were waiting for LADEE to confirm these simulations and add new data, but I didn't find any conclusions on this subject on the mission website. I was interested if this event can create a significant static electricity difference between the 2 sides of the Moon, causing some sort of lightnings on the edges or even a mini-version of a dust storm. You'd probably be most interested in the results of the Lunar Dust EXperiment (LDEX). A 2015 paper states
LDEX data show no evidence for an electrostaticallylofted
dust component at densities greater than a few
per m3
I am assuming the solar flare stuff didn't pan out, otherwise it would be mentioned in the various LDEX summary papers. In addition, the NASA DREAM group site doesn't seem to have anything relevant LADEE results, and they're the ones that brought the subject up in the first place.
The following is multiple choice question (with options) to answer.
the moon 's surface contains many | [
"trees",
"oceans",
"smoothies",
"ground bumps"
] | D | the moon 's surface contains many craters |
OpenBookQA | OpenBookQA-3756 | groundwater, earth-observation, geothermal-heat, underground-water
Title: Would the subsurface event leading to tree death at West Tern Lake in Yellowstone be visible in thermal imaging? The New York Times article It’s Warm and Stealthy, and It Killed Yellowstone Trees and Turned Soil Pale describes an even that took place over the past few decades where a small and well-defined forested spot in Yellowstone National Park underwent some change, killing all of the trees growing there.
Credit: United States Geological Survey
The article explains the possible explanation that the trees died from changes in subsurface water chemistry.
Dr. Vaughan perused the aerial shots taken of the suspicious region. In 1994, nothing seemed amiss and trees were growing healthily. However, from then through 2017, trees had perished, and the soil had turned a sickly off-white color. The only reasonable explanation was that a new thermal area had been covertly growing in the region since the late-1990s, altering the ground’s chemistry with its superheated fluids.
Parenthetically speaking, to me "superheated fluids" sounds like something that could kill trees thermally, even without chemistry.
Would heating like this show up as a hot spot in thermal IR Earth imaging? Or is this likely to have been too deep to result in a significant surface temperature change?
Google maps screen shot centered at 44.663584 N, 110.278843 W: If it’s hot enough to alter the groundwater chemistry that is killing the trees, then you would see it in satellite thermal imaging. Remember, tree roots only go down about 20 to 30 feet at the most, so this is all pretty shallow stuff. This is actually quite a strong thermal anomaly. Like you said, the heat alone may have killed the tree/tree roots.the white areas of the photos are likely salt deposits from the thermal water left behind after evaporation. So again, the thermal water is shallow, indeed, it’s right at the surface. Pretty cool.
The following is multiple choice question (with options) to answer.
wildfire that is passed through the tree tops are dangerous, why? | [
"it changes at the tip of a hat",
"it has magic powers",
"it creates a blackhole to suck up Earth",
"it has the power to travel in time"
] | A | drought may cause wildfires |
OpenBookQA | OpenBookQA-3757 | 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.
One of the reasons some species go extinct is because predators | [
"have school with them",
"tickle and cuddle them",
"murder too many of them",
"go dancing with them"
] | C | if a new predator begins eating prey then the population of that prey will decrease |
OpenBookQA | OpenBookQA-3758 | botany, entomology
Title: Health effect of worm in Guava I ate a ripe guava, rife enough to be broken with hand, i later saw that it has white worms with one black end crawling inside it, are these worm harmful, i had unripe guava of same batch though most of them had small black spot inside, but no worm crawling, what are these crawling worms, were they present in guava from unripe stage or infected only after ripening ? It is a safe bet that a "worm" as you describe in a ripe guava or any other ripe sweet fruit is a fruit fly.
from http://www.greenharvest.com.au/PestControlOrganic/Information/FruitFlyControl.html
Fruit flies are attracted to any ripe sweet fruit. They are also attracted to vinegar and alcohol - both produced by yeast in and on the fruit, which is the high protein food that the fruit flies are really after in the fruit.
from
http://homeguides.sfgate.com/treat-fruit-flies-guavas-30550.html
When ripe, guavas emit a pungent, musky odor that attracts fruit
flies. Fruit flies lay their eggs beneath the fruit's skin, and the
maggots feed on the flesh. The damage causes guavas to rot. Fruit fly
infestations often spread quickly, but prompt treatment can get
populations under control.
The fly large actually speed the rotting of the fruit by moving yeast around on their bodies.
The following is multiple choice question (with options) to answer.
Guavas with many leaves | [
"are mature",
"haven't grown",
"are immature",
"are birds"
] | A | when a plant grows , the number of the leaves of that plant may increase |
OpenBookQA | OpenBookQA-3759 | machine-learning, artificial-intelligence, neural-networks, classification, pattern-recognition
Neural network approaches.
Neural network approaches of collective classification divided into methods: that use neural network to combine multiple classifiers, ensembles of neural networks and those that use neural networks constructed from modules.
A neural network for combining classifiers
One approach uses a neural network to combine basic classifiers multiple decisions (Fig. 2). The output of each base classifier is a decisions vector (a vector containing 'soft tags' values), the values of which belong to a certain numerical interval [a, b]. These values are delivered to the neural network input (network must be trained to combine base classifiers decisions). The output of the neural network is a final decision in favor of one or another class. The output of the network can also be a vector whose dimension is equal to the number of classes of objects to be recognized that at each position has some confidence degree value in favor of one or another class. In this case, the class with a maximum value of such confidence value can be selected as a decision.
Decisions integration functionates as follows:
a number of base classifiers is selected and trained;
metadata for the neural network training is prepared. For that, base classifiers are tested using the interpreted data sample. Then for each test sample a vector of base classifiers decisions is generated. Then, a component which includes the true class value of the test sample is added to the decisions vector;
meta-data sample is used for training the neural network that performs decisions integration.
Modular neural networks method
For modular neural networks it is proposed to use the so-called gating network (neural network for assessing the classifiers’ competence for a particular input vector of data provided for classifiers). This option represents the neural network paradigm to integrate decisions based on competences. The corresponding theory is called mixture of experts. Each classifier is associated with the so-called "referee" program, which predicts its competence degree with respect to a specific input, that a set of base classifiers is provided with (Fig. 3).
The following is multiple choice question (with options) to answer.
One way to remember the method of Scientific Classification is | [
"run",
"dive",
"swim",
"make a sentence"
] | D | classifying means grouping materials by their properties |
OpenBookQA | OpenBookQA-3760 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is true? | [
"balloons and stars are composed of exactly the same materials",
"balloons and stars are the same size",
"stars and balloons share some of the same gases",
"balloons and stars contain sodium"
] | C | a star is made of gases |
OpenBookQA | OpenBookQA-3761 | geophysics, climate, rain, nitrogen
Title: Rain Water vs Sprinkler Irrigation During the rainy season, the crops like corn, cotton are found to be growing faster. Studies shows that the thermoelectric fixation of gaseous Nitrogen during rain storm accelerates the plants growth in rainy season.
Can this effect be seen in Sprinkler irrigation ?
Is it possible to mimic this effect in other irrigation methods? I think what you mean by thermo-electric nitrogen fixation is the nitric oxides created by lightning discharges. This is absorbed by the raindrops as they form and as they fall to earth, and helps to fertilise the soil. You won't get this effect with sprinkler irrigation to any great extent, because the water droplets are exposed to the nitrogen oxides for far less time. In addition, sprinkler use is not usually accompanied by lighting flashes, whereas rain sometimes is.
If your crops are watered mainly by sprinklers and you would like them to have more nitrogen, you should practice rotation of crops. Some years you plant legumes, which fix nitrogen by means of the nitrogen-fixing bacteria which live in the nodules in their roots. In the tropics, a kind of acacia called mimosa, though not related to legumes, has the same nitrogen-fixing capability. This acacia is sometimes called 'the sensitive plant', as when touched its leaves rapidly fold themselves away.
The following is multiple choice question (with options) to answer.
Sprinklers during the summer is prohibited because of | [
"documentation",
"vaporization",
"solicitation",
"rowdy neighbors"
] | B | evaporation is when water is drawn back up into the air in the water cycle |
OpenBookQA | OpenBookQA-3762 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
Which of these could be a reason why the stars seem to be in a different place at dusk than at dawn? | [
"rotation of the sky",
"rotation of the sun",
"rotation of the earth",
"rotation of the person"
] | C | the Earth rotating on its axis causes stars to appear to move across the sky at night |
OpenBookQA | OpenBookQA-3763 | tissue
Title: Tissues in plants and animals
What is the equivalent connective tissue in plants?
Connective tissue in animals are mostly made up of collagen.
What about in plants?
Connective tissue in animals are mostly made up of collagen
Tissue is not like a simple chemical mixture ; rather tissue means a group or assemblage of cells, obeying certain defining-characteristics.
Animal connective tissues contain collagen mostly in the extracellular matrix. There are also other cell-constituents like phospholipid(membranes), DNA, RNA, etc. Blood is a liquid connective tissue which do not contain collagen in its matrix (plasma)
What is the equivalent connective tissue in plants?
Connective tissue is defined as all the tissues originated from the mesoderm layer of the animal embryo.
Now plants have a different mode of development than animals (plausibly due to evolution in separate route). So no part of a plant-body is homologous with a part of animal-body. It is impossible to bring a compare.
However; plants too; have their extracellular matrix; which is more popular as plant's cell wall (that contain cellulose, hemicellulose, etc.) as well there are intercellular spaces.
Still, if you forcefully want to bring a comparison; then the ground-tissue system of plant maybe called as a rough analogy with connective tissues in animals ( Similarly epidermal tissue of plant maybe a rough analogy with epithelial tissue of animals)
The following is multiple choice question (with options) to answer.
Special tissues in plants transport minerals throughout what? | [
"flora",
"space",
"planets",
"atmosphere"
] | A | special tissues in plants transport minerals throughout the plant |
OpenBookQA | OpenBookQA-3764 | 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.
if a habitat is destroyed then that habitat | [
"is clean",
"is smelly",
"is super",
"is gone forever"
] | D | if a habitat is destroyed then that habitat can not support animals |
OpenBookQA | OpenBookQA-3765 | botany, plant-physiology, plant-anatomy
It made me wonder if we are simulating the sun in a dark room for growing the plants with the help of red, blue, and a little bit of far-red light, what will happen to the plants if we keep the ideal conditions for which the plants carry out photosynthesis whole day? Does it affect its yield or the plants die out quick?
I am an engineering student working on indoor farming, my knowledge of botany is the same as a high school student. So if I am wrong please tell me. Ideal conditions for photosynthesis
You mention ideal conditions to carry out photosynthesis, I would just like to point out that this includes carbondioxide levels, temperature, and nutrients as well as light.
Flowering
As anongoodnurse mentions performance might be measured by blooming which, in most flowering plants, has a day-light related component. However, for general growth increasing daylight over the 'natural' day length can often increase yield.
Daylight Cycles
The important point to note is that plants do 'ramp up' at dawn getting ready to start photosynthesizing (for some plants with temporal photosynthesis mechanisms (see CAM photosynthesis) this can be even more important). The reason plants do this is because plants can suffer from 'photobleaching' which can be considered similar to sunburn in humans, if they are not ready for sunlight. Getting 'ready' can involve lots of things including opening stomata (pores) to let CO2 in, changing which metabolic pathways are active, and moving about chloroplasts inside cells. Plants 'figure out' how and when to ramp up based on circadian rhythms which work well on 24 hour clocks and slight changes over time. Thus 12 hrs to 16 hrs can be a big change, particularly if the change happens by lights coming on earlier. Additionally, the 24 hour 'clock' means that plants will do better with 18hr light then 6hrs dark cycles than 36hrs light 6 hrs dark, because the total cycle length should be about 24hrs.
Photosynthesis Side Effects
The following is multiple choice question (with options) to answer.
You can use what to fake sunlight for plants? | [
"love",
"a flash light",
"breathing",
"water"
] | B | a plant light is used for help plants by mimicking sunlight |
OpenBookQA | OpenBookQA-3766 | soil-science
Title: How does humanure make soil "fluffier"? This BBC article says biosolids make soil "fluffier", among other benefits. How?
Adding humanure also changes soil structure, making it more resilient, preventing erosion and balancing out moisture, says Moss. It makes dirt fluffier, so water passes through easier. Conversely, in drought conditions, this also helps it retain water. The less compact soils are also softer, enabling seedlings to take faster and grow stronger roots, producing better yields. What are Biosolids and how do they work?
a biosolid is a product of the sewage treatment processes and is a semi-solid sludge of organic matter, nutrient-rich organic compounds. Here I list several reasons as to why biosolids would make the soil 'fluffier' and and better
As I said earlier biosolids are typically made out of organic matter, organic matter is carbon-based and biosolids are usually biological material (decomposed feces, urine and et cetera).
If you are not familiar with the normal decomposition processs it is a biological material (banana, apple, feces and et cetera) that is decomposed by microbes, molds, fungi and etc
biosolids are biological and/or organic material so what I just stated above applies to biosolids as well
Think of what you flush down a toilet or what goes down a sewer drain, are those things carbon based and biological? (human feces is an organic-compound and it goes in the sewers)
So now we know that biosolids are like other organic-compounds, how does this maker the soil fluffier. When something undergoes decomposition it turns into fresh brand-new soil, and quite obviously this new soil would be much more higher-quality and better than over-used old soil.
Here it states that organic material in a landfill produce gases due to decomposition so it makes sense that the same process would happen underground where microbial decomposition can release gases in the soil thus making the soil fluffier
So I can conclude that biosolids do, in fact help soil and make it fluffier and better.
The following is multiple choice question (with options) to answer.
which one of these would make a great organic manure later on? | [
"a plastic spoon and fork",
"a white plastic chair",
"a family of raccoons",
"a plastic water bottle"
] | C | plastic is a nonrenewable resource |
OpenBookQA | OpenBookQA-3767 | development
Title: How detachment/separation works in biology? It might be a strange question, but I'm interested in the mechanics of separation/detachment during asexual reproduction, for example when an organism reproduces by budding (I don't mean cellular budding like baker's yeast). When the newly formed body is fully matured it detaches itself from the parent / original body.
It might not be caused by a specific tissue, as animals with not so differentiated bodies are (also) capable of such, but I could easily be wrong. Is this (the detachment) triggered by changes in the cell membrane? I can't really think of other explanations. Reproductive budding and what you call 'cellular budding' are really highly related processes. Budding as a form of reproduction essentially partitions protein aggregates and damaged cellular components into the host or mother and builds fresh or 'young' cells on the opposite side of a partition. To begin understanding this look at Saccharomyces cerevisiae (budding yeast) which forms protein rings (from the septin proteins) at the membrane, around the bud neck which separates the mother and daughter cells Hartwell 1971. This ring acts a partition that in part, withholds protein aggregates and certain proteins from diffusing from the mother to the daughter. This protein ring is an example of how cells limit diffusion of proteins and cellular components to the daughter cell. Another good example that comes to mind is Linder 2007, though it is done in E Coli, not budding yeast, where mother cells maintain protein aggregates and age, while the daughter cells are given fresh components and are therefore more fresh and 'young'.
Now like you mention, imagine this process in a multicellular organism to be fundamentally the same. At some point the multicellular organism will start an outgrowth of cells, while restricting what materials are given to the daughter cells to maintain their youth. And eventually a new organism will have been created. Some of the details will be different, but the fundamental process is is quite similar. In that you start with an old cell that creates a new cell from scratch, but rather than splitting all cellular components equally between mother and daughter, the daughter cells is made in peak condition while the mother cell retains much of the cell 'junk' like protein aggregates.
Hopefully that starts to answer your question.
The following is multiple choice question (with options) to answer.
Breaking free from it's cocoon is the last part it's | [
"mid-life crisis",
"mutation",
"fashion sense",
"diet"
] | B | a moth undergoes metamorphosis |
OpenBookQA | OpenBookQA-3768 | electrical-engineering, refrigeration
Title: Relative inefficiency of doorless fridges at supermarkets It appears to be a waste of electricity to keep a bank of refrigerators wide open with no doors or covers whatsoever on them.
They seem to be just blowing cold air out into the supermarket.
They are not turned off at night when the store closes. Even the "green" Whole Foods-type places do this.
But is it really that inefficient to operate them that way?
What is the relative efficiency between a refrigerator with a door and one without a door in a supermarket? The doorless models (this was the photo in the question when I answered it) aren't as inefficient as they appear to be.
Whenever someone opens a regular fridge door, its cold air pours out onto the floor and warm air replaces it inside the fridge. If the doors are opened frequently, or held open for significant time, there is a lot of waste.
On the other hand, the doorless models are designed to have a laminar flow of cold air from top to bottom. Most of the cold air emitted at the top is sucked back in at the bottom, with far less mixing with the surrounding warm air than one might think.
So for products where temperature control isn't critical, and where many people are likely to take the product or to spend a long time looking and deciding, the doorless models are a good choice.
(They're also good from a marketing perspective, as they provide an excellent view of the product and don't have doors that fog up, but that's not the question.)
The following is multiple choice question (with options) to answer.
which one of these places would a person have the least need for a clothes dryer? | [
"in the tropical rain forest",
"in a humid cave",
"in the hot desert",
"in a wet town"
] | C | a desert environment is dry |
OpenBookQA | OpenBookQA-3769 | energy, visible-light, photons, sun, interactions
Title: What are the physical processes involved in feeling warm from the sunlight? Suppose a human is lying on a beach. He/she starts to feel warm after exposing his/her skin to the sunlight. I assume that feeling is due to the ability of the human body of "measuring" the increasing in temperature of the skin.
Now I want to understand what are the physical processes involved in this increasing in temperature.
Imagine a group of photons impinging on the skin in a certain interval of time. I tried to list the possible interactions from a particle physics perspective between photons and the human tissue and I concluded that the possible interactions may be:
Photoionization
Compton scattering
Rayleigh scattering
Pair production
The first 3 seems to be reasonable, but the fourth one requires an energy threshold too high: there are no incident photons that may have that energy. I conclude that by looking at the spectrum of sunlight that actually reaches the earth's surface below the atmosphere. So I think that the pair production does not play a role in this situation.
Are there any other interaction processes between photons and tissue molecules involved in the increasing of temperature of the human tissue?
After listing the processes I wonder what actually increases the temperature: is the temperature increasing because the photons-molecules interactions lead to a transition of molecules to excited vibrational states? or maybe transitions to excited rotational states?
I thought that another possibility is that the photons interactions are increasing the kinetic energy of the water molecules in the skin or maybe are increasing the lattice vibration of other tissue (skin, bones or others). Are this processes happening simultaneously? One of this processes (for example transition to rotational excited states) is dominant over the others ?
I'm looking to a qualitative answer, without going into too much details of the Biology of the human body. I just want to create an approximate picture of this situation in my mind. I want to create a mental "video" from the instant in which a photon or a group of photons impinges in the skin to the moment in which tissue molecules are affected and the temperature starts rising up.
I thank in advance anyone who answers this question. You forgot garden-variety absorption! Here, light promotes electrons from lower energy states to higher energy states. However, skin is made of many small particles, so scattering is important as well.
Here’s the mental video:
The following is multiple choice question (with options) to answer.
in the presence heat, which of these comes about? | [
"a melted snocone at the cafeteria",
"an ice cream cone",
"a piece of gum",
"a large metamorphic rock"
] | A | adding heat to something kills viruses in that something |
OpenBookQA | OpenBookQA-3770 | mountains, rainfall
Title: Could a waterfall lashing onto a road lead to a landslide? Here is a video of a waterfall lashing on to a mountain road, with vehicles driving under it.
https://youtu.be/cHaguj--YBc
There appears to be a big hole carved out right next to the road, possibly by the force of the waterfall.
Is this a ticking time bomb for a landslide? Potentially, a landslide could occur. Whether it would be a minor slip or a major fall depends on the geological conditions at the site, the force of the water and the duration that the site is impacted by the water.
In the video in question, the rock face above the road appears competent, but there are not guarantees. The main issue would be is the water undermining the road which could cause a slip and the road to slide.
The more loose the geological material is, the easier it is to dislodge it. Once one item moves a chain of events can occur where additional items are dislodged and a slide occurs.
In addition to high pressure water dislodging material, water acts as a lubricant, making it easier for rocks and regolith to be dislodged.
To minimise the potential for a slide to occur in such a situation, the surface of the road would need to be sealed very well and a very good drainage system installed that would move the water away from the road and the slope below the road
The following is multiple choice question (with options) to answer.
If a creek is headed to the west and a stone is tossed in and sinks, but a leaf also drops in and stays on top of the water, what will likely happen? | [
"the leaf heads west",
"the stone will burn",
"the stone floats up",
"the leaf heads north"
] | A | flowing liquid can push objects |
OpenBookQA | OpenBookQA-3771 | 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 little rat startles a cat and ends up as the cat's lunch. What does that make the car? | [
"the cat is a dog",
"the cat is a bad cat",
"the cat is carnivorous or omnivorous",
"the cat loves milk"
] | C | if an animal eats another animal then that animal is a carnivore or omnivore or predator |
OpenBookQA | OpenBookQA-3772 | evolution, cell-biology, molecular-evolution
Title: can a cell evolve into a different species in the lab? A friend of mine does not believe in evolution. He claimed that we can not as humans observe a single cell evolving into a different cell. Is that possible to be observed in the lab?
Thanks in advance. First it is worth noting individuals don't evolve, populations evolve.
We can observe cells giving rise to different cells, the long term E.coli experiment is a famous and ongoing example, not only can evolution be observed but because sample cells from the population are taken and frozen periodically, it can be repeated! that is you can observe a change then set up the same line of cells under the same or under different conditions to see if the changes are different. In some cases even the exact same mutations can be observed.
https://en.wikipedia.org/wiki/E._coli_long-term_evolution_experiment
http://myxo.css.msu.edu/ecoli/
https://www.pnas.org/content/105/23/7899
The following is multiple choice question (with options) to answer.
Single cell organisms can put an animal in the | [
"funny farm",
"space program",
"emergency room",
"hall of fame"
] | C | bacteria can cause people to become ill |
OpenBookQA | OpenBookQA-3773 | thermodynamics, temperature, everyday-life, phase-transition, humidity
Title: Steam from a cup of coffee I observed that, in winter there is more visible steam from a cup of coffee than in summer. Is there any phenomenon taking place here. The amount of water that air can take up before the water creates fog or visible steam depends on temperature. The colder the air, the less water it needs to create fog/steam. It is the same principle when hot air rises, for example when pushed up a mountain and then it starts to cool down drastically --> It will rain.
For more have a look at: Relative humidity in https://en.wikipedia.org/wiki/Humidity
The following is multiple choice question (with options) to answer.
steam is a kind of water above | [
"the stove",
"373 kelvin",
"the moon",
"jupiter"
] | B | steam is a kind of water above 100 degrees celsius |
OpenBookQA | OpenBookQA-3774 | solar-system, coordinate, stellar-astrophysics
Can you see either in the sky now. Do they look the same? If yes you are in the same hemisphere you normally live in. If they look strange - upside down. You are in the hemisphere opposite to where you normally live.
You've just spent the rest of the night looking at the sky and the Sun is up. Observe the path Sun, in the sky, during the course of the day. If it is low, it winter. If it is high, it's summer. The daytime temperature will also confirm this.
The following is multiple choice question (with options) to answer.
As the earth tilts towards the sun you will see | [
"frozen glaciers",
"yards being mowed",
"blizzards daily",
"leaves being raked"
] | B | seasons cause change to the environment |
OpenBookQA | OpenBookQA-3775 | fluid-dynamics, everyday-life, water
As can be seen from these photos, the colour dye is present in the water jets which recoil off the surface of the transparent pool water. However, not all of the water in the jets is from the coloured drop. Some of the original drop is trapped in a pocket below the surface, with the rebounding 'jets' having a 'coating' of the original drop material. The way we know this is because in the experiment, the coloured drop was made from water mixed with thymol blue, an indicator which is dark orange in colour at neutral-to-acidic pH. The pool water contained 0.1% sodium carbonate (alkali), which is transparent in colour, but when the two combined, the mixture turns blue in colour.
Some fascinating insight into the phenomenon can be gained by examining some high speed video footage.
If you look at this high speed video, you will see that when the water droplet falls into the water, it appears to bounce back out!
An even better example of the 'bouncing' phenonenon can be found in this video, when the drop is released gently from close to the surface of the water, it appears that after the drop is 'coalesced' into the water, part of it 'bounces' back out as a smaller droplet, which the falls back and floats on the surface of the water.
The explanation offered is that a layer of air gets trapped beneath the droplet as it hits the surface of the water. Some of the water in the droplet gets coalesced into the pool by the water tension, releasing a smaller droplet back out.
The following is multiple choice question (with options) to answer.
A plastic toy reduced to a puddle was left on a | [
"steep mountain",
"iceberg",
"government propaganda flick",
"hotplate"
] | D | melting is when solids are heated above their melting point |
OpenBookQA | OpenBookQA-3776 | reproduction, digestion, sexual-reproduction
Hazardous components of pollen:
Trace amounts of hepatotoxic pyrrolizidine alkaloids were found in pollen of Echium vulgare, E. plantagineum, Senecio jacobaea, S. ovatus, and Eupatorium cannabinum (Boppre et al., 2008). In Middle and Northern Europe these pollens are not among the main pollen grains gathered by bees, however in Southern Europe the two Echium plants are more diffused and are gathered by bees in larger amounts (Campos et al., 1994; Serra Bonvehi, 1997). [Source 1] (Page 5)
Therefore, it should undergo tests to approve it's purity as allergies can be caused.
References:
1 : Future of bee pollen(Research gate)
2 : Pollen composition and standardisation of analytical methods(Research gate)
3 : Hollow pollen shells to enhance drug delivery(NCBI)
4 : Bee pollen: chemical composition and therapeutic application(NCBI)
5 : Biological activities of commercial bee pollens: antimicrobial, antimutagenic, antioxidant and anti-inflammatory(NCBI)
6 : Biological and therapeutic properties of bee pollen: a review(NCBI)
The following is multiple choice question (with options) to answer.
If a thing is a producer of pollen and seeds, it may be located in | [
"a cabinet",
"a bag",
"a microwave",
"a vase"
] | D | a flower produces pollen and seeds |
OpenBookQA | OpenBookQA-3777 | death
Title: What would cause crows to be attracted to a human body? On another SE site, there was a comment that told me something about biology that I already know:
"A man left murdered in the fields would soon have a flock of crows mobbing his fragrant corpse."
But I don't quite understand why. Is it the "death" part,the fact that someone was injured/bleeding or just the fact the he was immobilized,that would attract the crows?
That is suppose you tied up someone and left him on the field. Would that attract the crows?
Suppose this person fell down, was bleeding, and immobile, but not seriously injured? Or is it the death part? I think the key is "his fragrant corpse." When an animal dies and begins to rot, a number of quite smelly chemicals are given off, including putrescine and cadaverine. Crows and other carrion birds like vultures are probably very sensitive to these compounds, rather like sharks are to the smell of blood.
The following is multiple choice question (with options) to answer.
If a young tern is found in a locked box, dead, without marks on it, a the most likely cause of death was | [
"violent stabbing",
"accidental shooting",
"ceremonial burning",
"untouched asphyxiation"
] | D | an animal requires air for survival |
OpenBookQA | OpenBookQA-3778 | Case 1: (3,1,1) First choose which of the 3 pockets will get three marbles. There are 3C1 =3 ways to do this. Then, choose the number of ways we can place 3 marbles into that box from 5 marbles. There are 5C3 = 10 ways to do this. Next we must place a marble in the next to the last box. There are 2C1 = 2 ways to do this. Then there is 1C1 = 1 way to place the last marble into the last pocket. Each time we make a subsequent selection when working through a case we multiply, so there are 3*10*2*1= 60 ways to place the marbles in case 1
Case 2: (2,2,1) First we must select which two pockets get two marbles each. There are 3C2 = 3 ways to do this. Then, we must choose two marbles to go in the first of two pockets. There are 5C2=10 ways to do this. From the 3 remaining marbles, there are 3C2 = 3 ways to place two marbles in the second pocket. Finally there is 1C1 =1 way to place the last marble in the last box. Multiplying, we have 3*10*3*1 = 90 ways to place the marbles in case two.
Thus there are 60+90 = 150 ways we can place the marbles
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Re: In how many ways can 5 different colored marbles be placed in 3 distin [#permalink]
### Show Tags
04 Oct 2019, 22:44
praffulpatel wrote:
In how many ways can 5 different colored marbles be placed in 3 distinct pockets such that any pocket contains at least 1 marble?
(A) 60
(B) 90
(C) 120
(D) 150
(E) 180
Solved it a little differently than others from what I read . So will share.
I first made sure that each of the pocket has at least 1 marble.
That is 5C3 * 3!
The following is multiple choice question (with options) to answer.
Marbles in the right light make | [
"rainbows",
"thee channel change",
"demons appear",
"the sun appear"
] | A | a rainbow is formed by refraction of light by splitting light into all different colors |
OpenBookQA | OpenBookQA-3779 | biochemistry, botany, plant-physiology, photosynthesis, agriculture
The above image is an example of a "potato battery" made without the potato. Identical setup and the energy obtained is identical given everything else the same.
Potato power- er, metal power?
This experiment is supposed to demonstrate the concept of an electrochemical cell. Electrochemical cells obtain their energy from the reduction-oxidation reactions that happen between two metals with different reduction potentials. When two metals - such as copper and zinc - are placed in a medium that permits the exchange of electrons and ions, an electrical gradient is produced as electrons move from one metal to the other and ions move the other direction. This gradient can then be captured and used to do work such as powering a lightbulb or an AI.
In the potato powered example, the power comes from zinc and copper. If you want a more powerful battery, use more zinc and more copper- not a bigger potato. If that is not good enough, try replacing the zinc with something like lithium- this is what we've done with modern, rechargeable batteries.
In truth, the potato battery would be better described as a normal battery that just happens to be inserted into a potato. You'll make a better battery if you use copper pennies and aluminum foil in vinegar.
I do not mean to shoot down your idea, and I am glad you are looking into renewable energy sources- but you may be better served by a class on electricity and batteries than by asking questions on biology.SE!
EDIT: I would assume that the electrical potential of this kind would also kill the plant, given that you're essentially electrocuting it. However, I was unable to find any information on the resistance of potato plants to electrocution.
The following is multiple choice question (with options) to answer.
Which of these might use plants for an energy source | [
"television",
"station wagon",
"toy car",
"action figure"
] | B | plants are a source of biofuel |
OpenBookQA | OpenBookQA-3780 | homework, reproduction, allele
Title: Albinism inheritance problem: what are the father's alleles if he got an albino kid?
Albinism is caused by a recessive gen "c". A normal man marries an
albino woman. The first son happened to be albino. What are the
possible phenotypes of the parents? What is the chance that their
other kids will be albino?
Alright, since "c" is recessive and the woman is albino, then the woman must be "c c" right? And since the son is albino, he must be "c c" too. Hence the father must have at least one "c". But since he is normal, then the other allele must NOT be "c" too (otherwise he would be albino).
My question is, when writing the Mendel table, how do I express that allele of the father (the one that is not "c")?
$$\begin{bmatrix} & c & c\\
? & ?c & ?c\\
c & cc & cc\end{bmatrix}$$
I marked it with $?$ because I'm not sure what to put there. My first thought was "well, it could be a capital C I guess..." - but that doesn't sound right to me. A capital C would mean there is a dominant albinism allele (but I am told that albinism is recessive only...)
I can see clearly that there is a 50-50 chance of having albino kids. I just don't know how to draw that inheritance table. Super oober short answer: The father is Cc, the mother is cc, there is a 50% chance the children will be albino (as you predicted).
An explination on Mendelian genetics:
First let's look at (what a lot of people consider) the normal Mendel table from here:
The following is multiple choice question (with options) to answer.
Who is likely to receive its coloration and hairy body from its parents? | [
"Peter the Parakeet",
"Valentina the Vole",
"Terry the Tuna",
"Greta the Grouper"
] | B | the coloration of fur is an inherited characteristic |
OpenBookQA | OpenBookQA-3781 | 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.
The floating arrow on a compass always points away from the | [
"east",
"south",
"west",
"north"
] | B | the floating arrow on a compass always points towards the north |
OpenBookQA | OpenBookQA-3782 | zoology, experimental
Title: Fish "coming back to life" after being frozen I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says:
For everyone that is worried about the goldfish, it survived and was perfectly fine until we fed him and a few of his friends to our turtles. (Which is what they were bought for in the first place!)
I am wondering now as to several issues.
If the goldfish wasn't fed to the turtles and was allowed to live out its life, would it suffer any long term damages from the act?
Is time an issue here, if the fish was kept frozen for a longer time, would it suffer more damage and would it be able to be revived?
Is the size and nature of the fish's body a factor? Would a larger animal or an animal with better resistance to frost that would take more time to completely freeze have damage due to gradual freezing of body and systems?
Does the fact that fish have cold blood affect the result of the experiment? I have no idea what's the real reason for the survival of the poor fish, but I would guess this is all in the timing. I know for certain ;-) that one can submerge a hand in liquid nitrogen for a short time or in general one can pour liquid nitrogen on the skin with no harm done whatsoever.
The reason is that the difference in temperature that interface (-180 deg C or so for liquid nitrogen and 20-30 for the skin surface) is so large that nitrogen vaporizes instantly and does not penetrate/affect the tissue. The demonstrator could have pulled the fish with bare hands.
I think that for the goldfish the time was too short and while it was cooled/shocked a bit, it might have been too short to do any serious damage. But -
As a scientist, I can't help but notice that we don't really know the condition of the fish before or after the liquid nitrogen 'treatment'. We only see it flapping for a few seconds when back in water. I wonder what happened to the eyes and the mouth, both quite sensitive tissues for such a shock. Also, the water the fish was in was a factor probably, providing additional buffer between the fish and the liquid nitrogen.
Last but not least, the ethical committee quite certainly did not approve that demonstration.
The following is multiple choice question (with options) to answer.
a scuba diver startles an octopus, and suddenly the water changed color, what happened? | [
"it died and released a color",
"it was amused by the diver",
"it was trying to hide from the diver",
"it was thanking the diver"
] | C | ink is used for hiding from predators by octopuses |
OpenBookQA | OpenBookQA-3783 | ### Show Tags
23 Dec 2016, 09:03
2x+50/5x+40=4/6, find x, then don't get into decimals, approx 17.something then 2(17)+5(17)= approx 122
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9558
Location: Pune, India
Re: Two mixtures A and B contain milk and water in the ratios [#permalink]
### Show Tags
09 Nov 2017, 02:28
4
bmwhype2 wrote:
Two mixtures A and B contain milk and water in the ratios 2:5 and 5:4 respectively. How many gallons of A must be mixed with 90 gallons of B so that the resultant mixture contains 40% milk?
A. 144
B. 122.5
C. 105.10
D. 72
E. 134
Responding to a pm:
Here is the weighted average method of solving it:
Concentration of milk in the first mixture = 2/7 = 18/63 = 90/315
Concentration of milk in the second mixture = 5/9 = 35/63 = 175/315
Concentration of milk in the resultant mixture = 2/5 = 126/315
w1/w2 = (A2 - Aavg)/(Aavg - A1)
w1/w2 = (175/315 - 126/315) / (126/315 - 90/315) = 49 / 36
So 36 gallons of mixture B needs 49 gallons of A
90 gallons of B will need (49/36)*90 = 122.5 gallons
The numbers in the question are hard to work with. In most GMAT questions, the numbers fall easily in place. It is the concept that you have to focus on.
_________________
Karishma
Veritas Prep GMAT Instructor
Senior SC Moderator
Joined: 22 May 2016
Posts: 3284
Two mixtures A and B contain milk and water in the ratios [#permalink]
### Show Tags
09 Nov 2017, 11:23
1
1
bmwhype2 wrote:
Two mixtures A and B contain milk and water in the ratios 2:5 and 5:4 respectively. How many gallons of A must be mixed with 90 gallons of B so that the resultant mixture contains 40% milk?
The following is multiple choice question (with options) to answer.
A good mixture would be | [
"water and olive oil",
"coffee and almond creamer",
"salt and fresh tacos",
"sugar and frozen milk"
] | B | An example of a mixture is clay mixed together |
OpenBookQA | OpenBookQA-3784 | species-identification, zoology, marine-biology, ichthyology, bone
Title: Identification of a strange skull My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it? Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site).
I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is indeed a neurocranium.(source of the picture).
Thank you all for your help!
The following is multiple choice question (with options) to answer.
A sea cow would be most uncomfortable in | [
"a desert",
"a fjord",
"an ocean park",
"lots of water"
] | A | a desert environment is low in availability of water |
OpenBookQA | OpenBookQA-3785 | everyday-life, diffusion, navier-stokes, convection
Diffusion in still air over distances of 400m usually takes a few hours rather than seconds, so I think that advection (the bulk movement of air) is likely to have been the dominant factor in the reported cases (as you suggested). Windspeeds at 10m above ground are typically 5m/s, decreasing downwards, so a transport time on the order of 100s is reasonable. Strong winds would reduce this time, but the descriptions "within seconds" and "almost instantly" seem somewhat exaggerated.
The following is multiple choice question (with options) to answer.
Clouds flit and flow | [
"in a bank",
"on the internet",
"above our heads",
"in cloudless skies"
] | C | water vapor is found in the atmosphere |
OpenBookQA | OpenBookQA-3786 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
Which is likely to be a step in a shrub's reproductive process? | [
"a logger chops the shrub down",
"a fire ravages the shrub and its local ecosystem",
"a human makes a smoothie out of some raspberries",
"a hare eats its berries and deposits leftovers far away"
] | D | pollination requires pollinating animals |
OpenBookQA | OpenBookQA-3787 | 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.
An example of evaporation is a body of water drying up by | [
"prolonged solar expsosure",
"cooking lunch",
"taking naps",
"smiting enemies"
] | A | An example of evaporation is a body of water drying up by absorbing heat energy |
OpenBookQA | OpenBookQA-3788 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
What to humans do that causes animals to lose their habitats? | [
"make apartments",
"take walks",
"sing songs",
"eat corn"
] | A | humans moving into an environment usually causes native species to lose their habitats |
OpenBookQA | OpenBookQA-3789 | qiskit
In general, the state will collapse to one of the possible states. Then the resetted qubit state will change to become zero if it is not zero already.
The following is multiple choice question (with options) to answer.
Which is likely to disappear? | [
"the last surviving member of a population",
"a male and female rabbit",
"a male and female horse",
"a wild dandelion root"
] | A | if all members of a species cannot produce offspring then that species will likely become extinct |
OpenBookQA | OpenBookQA-3790 | physiology, ichthyology
Salmon use to deal with the NaCl fluxes driven by the gradients between the salmon and its surroundings. In their gill epithelial cells, salmon have a special enzyme that hydrolyzes ATP and uses the released energy to actively transport both Na+ and Cl- against their concentration gradients. In the ocean, these Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the salmon's blood into the salt water flowing over the gills, thereby causing NaCl to be lost to the water and offsetting the continuous influx of NaCl. In fresh water, these same Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the water flowing over the gills and into the salmon's blood, thereby offsetting the continuous diffusion-driven loss of NaCl that the salmon is subject to in fresh water habitats with their vanishingly low NaCl concentrations.
Reference
Reference
The following is multiple choice question (with options) to answer.
a fish lives in water and filters the water through its | [
"tail",
"gill slats",
"eyes",
"fins"
] | B | a fish lives in water |
OpenBookQA | OpenBookQA-3791 | homework-and-exercises, electrostatics, electric-fields, electric-current, potential
Title: Why charges does not move through the conductor here if potential at both ends of wire is same? Two conducting solid spheres are kept apart, one with charge Q1 and radius R1 and the other with charge Q2 and radius R2.
Q1=5Q2 and R1=5R2
When these spheres are connected by a conducting wire, the potential at both ends of the wire is the same.
I understand that the electrons will arrange themselves in such a way that the electric field inside the conductor will be zero.
However, electrons closer to the spheres would be attracted to them in this arrangement.
The question is why, despite being attracted to positive charges on the sphere, they (electron nearer to the surface of spheres) did not leave the wire and enter (flow through) the conductor (sphere), given that spheres are far apart
What's keeping it from happening?
A thoughtful response would be greatly appreciated.
The electric field inside the conducting wire is zero due to electron rearrangement BUT the potential on each individual sphere is not zero, the difference is zero, and the NET current is zero, so the electrons near the sphere must be attracted to it, but they did not migrate to the sphere, why?
You should not assume the wire is electrically neutral. It is not. If it were, you wouldn't have an equipotential over the whole conductive region. You'd just have exactly the same potential distribution you had before you connected the wire.
So the electrons did migrate, when you first connected the wire, from the wire onto the two spheres. Now that the system has come to equilibrium, there's no longer a potential difference along the wire to drive the electrons to move further.
The following is multiple choice question (with options) to answer.
If one electrical conductor touches another one what will flow through them both? | [
"zapping power",
"tea",
"water",
"milk"
] | A | if one electrical conductor contacts another electrical conductor then electricity will flow through both conductors |
OpenBookQA | OpenBookQA-3792 | reaction-mechanism, safety
Title: What are the consequences of mixing Ferric Chloride Solution, distilled vinegar, baking soda and water? I was attempting to etch and blade with a ferric chloride solution. I did not have enough so I filled a glass with vinegar and water (3 parts vinegar to 1 part water) then added 2 oz. of ferric chloride solution. I added baking soda later to neutralize the ferric chloride solution, but was met with a deep red foam. I quickly added more baking soda and flushed the solution down a deep sink in my basement. I rinsed out the sink and glass with water and continued to add baking soda to neutralize any ferric chloride solution that had been spread by the red foam. What reaction occurred and is this and do I need to worry about it? I suspect the red salt you are seeing is Iron (III) carbonate, which was likely created from, as you noted, the neutralization of aqueous Iron (III) chloride with Baking Soda (in excess?) per the reactions:
$\ce{FeCl3 (aq) + 3 NaHCO3 (aq)-> 3 NaCl (aq) + 2Fe(HCO₃)₃(aq)}$
$\ce{2Fe(HCO₃)₃ (aq) → Fe₂(CO₃)₃ (s) + 3H₂O (l) + 3CO₂ (g)}$
$\ce{2Fe(HCO₃)₃ + HAc (aq) → Fe₂(Ac)₃ (s) + 3H₂O (l) + 3CO₂ (g)}$
where the last reaction could also lead to Iron (III) acetate from the vinegar presence, which is also subject to further neutralization by the Baking Soda.
The following is multiple choice question (with options) to answer.
Baking soda can react chemically with what? | [
"oxidized alcohol",
"sunlight",
"dirt",
"wind"
] | A | baking soda can react chemically with vinegar |
OpenBookQA | OpenBookQA-3793 | If the question is asking for the probability that either of the two cows is 2-coloured, we have
$$P(\text {1 cow is 2-coloured | both visible sides are black}) = \frac{P(\text {1 cow is 2-coloured and other is black}) \times P(\text {the black side of the 2-coloured cow is seen})}{P(\text{both visible sides are black})}=\frac{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}}{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}+\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}}=\frac{1}{2}$$
where $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when one is 2-coloured and the other is black and $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when both cows are black (these exhaust all possibilities for both visible sides being black).
The following is multiple choice question (with options) to answer.
Incinerating half a herd of cows means there will be | [
"fewer cows",
"slightly more cows",
"more cows",
"many more cows"
] | A | harming an animal species causes that animal 's population to decrease |
OpenBookQA | OpenBookQA-3794 | electrostatics, charge, capacitance, conductors, estimation
This implies that
$$
C = 4 \pi \epsilon_0 \frac{\sqrt{c^2 - a^2}}{\cosh^{-1} (c/a)}.
$$
If we approximate a spoon as an ellipsoid of length 20 cm and diameter 2 cm, we have $c = 10$ cm and $a = 1$ cm, and we obtain $ C \approx 3.7$ pF.
As another example, if we approximate a human body as an ellipsoid with $c = 80$ cm and $a = 20$ cm, we obtain $C \approx 42$ pF. We can see that this is within an order of magnitude of estimates found elsewhere.
For an object that is better approximated as an oblate ellipsoid, with $a = b > c$, the integral is slightly different, and the capicatnce turns out to be:
$$
C = 4 \pi \epsilon_0 \frac{\sqrt{a^2 - c^2}}{\cos^{-1} (c/a)}.
$$
If a frying pan has a radius of $c \approx 15$ cm, and a thickness of about 4 cm (so $a \approx 2 cm$), then $C \approx 11.5 pF$. Still smaller than that of a human body.
Finally, note that in both cases, for a given ratio of $c/a$, the capacitance of a body scales linearly with its size. This is a general property that can (I think) be proven rigorously for bodies of arbitary shape via arguments based on the properties of Laplace's equation.
The following is multiple choice question (with options) to answer.
The size of a persons head is | [
"changed",
"calculated",
"determined by food",
"predetermined"
] | D | the shape of body parts is an inherited characteristic |
OpenBookQA | OpenBookQA-3795 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
To have a positive impact of the environment | [
"use Styrofoam plates and bowls",
"use more paper towels",
"drive a car that guzzles gas",
"salvage plastic bottles instead of throwing them away"
] | D | conserving resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-3796 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
It's easy to be crushed by rocks lounging | [
"near a sloping mountainside",
"on a frozen pond",
"on a mall escalator",
"in the middle of a peaceful cemetery"
] | A | landslides often occur on mountains |
OpenBookQA | OpenBookQA-3797 | energy, photons, semiconductor-physics, solar-cells
In down-conversion one high energy photon promotes an electron from 1 to 3, and by falling to energy level 2 and then 1, two photons can be emitted. Thus one high energy photon in and two low energy photons out.
Of course the next step would be to use a solar cell to collect the converted photons. The up and down converters themselves don't generate power.
Other approaches
There are other approaches to reaching higher efficiency. In specially engineered materials high energy photons can generate multiple electron-hole pairs which provides more current per photon than normal solar cells.
Then there are the hot-carrier approaches. If a material and maintain a thermal gradient then this provides an additional thermodynamic potential allowing higher efficiencies to be achieved.
You can even use hot-carrier materials as a spectral converters! I've worked on this approach over the last few years.
The following is multiple choice question (with options) to answer.
a solar panel converts astral radiation into electricity which charges a rechargeable battery that can go into an | [
"cupcake",
"rock",
"illuminated police baton",
"stick"
] | C | a solar panel converts sunlight into electricity |
OpenBookQA | OpenBookQA-3798 | # ONEORTWO - Editorial
Author: utkarsh_25dec
Testers: tabr, iceknight1093
Editorialist: iceknight1093
TBD
None
# PROBLEM:
There are two piles of stones: the first with X, the second with Y.
Chef and Chefina alternate moves, with Chef moving first.
• Chef can either remove one stone from both piles or remove two stones from the first pile.
• Chefina can either remove one stone from both piles or remove two stones from the second pile.
Under optimal play, who wins?
# EXPLANATION:
Note that Chef always removes at least one stone from the first pile, and Chefina always removes at least one from the second.
So, ideally Chef always wants there to be stones remaining on the first pile, while Chefina always wants there to be stones remaining on the second pile.
Intuitively, this should tell you that both players will use the “remove one stone from both piles” move as much as possible.
This fixes the set of moves of the game, and so it can be easily simulated to see who wins.
A little bit of casework should tell you that:
• If X \geq Y+2, Chef will always win.
• If X = Y+1, Chef will win if X is even and lose otherwise.
• If X = Y, Chef will win if X is odd and lose otherwise.
• If X = Y-1, Chef will win if X is odd and lose otherwise.
• If X \leq Y-2, Chef will always lose.
This can be simplified into:
• If X \geq Y+2, Chef wins
• If X \leq Y-2, Chef loses
• if |X-Y| \leq 1, Chef wins if and only if \min(X, Y) is odd
In fact, this intuition is correct, and the above cases solve the problem!
Detailed proof
Intuition is great to have, but can’t always be relied on. It’s good to get into the habit of proving your solutions.
Let’s prove the above cases by constructing a strategy for them.
The following is multiple choice question (with options) to answer.
A contractor could take the granite off your kitchen counter and | [
"break it with feathers",
"damage it with a couple ice cubes",
"destroy it in a volcano",
"make it really feel badly about itself"
] | C | being exposed to heat can cause erosion of rocks |
OpenBookQA | OpenBookQA-3799 | gravity, fluid-dynamics, pressure
Title: Swimming in a ball of water in space What would I feel if I went swimming in a ball of water in space? Would I feel greater pressure as I went deeper into the sphere? What would it be like to swim in something like that?
Also, let's say that I don't need air to survive in this scenario. Best answer is given from xkcd's what-if: https://what-if.xkcd.com/124/. It's not space, but it describes the fluid flow in lower gravity - such as how you could jump out of the pool just by performing aquadynamic maneuvers, or walk on the water. It is really a cool read.
As mentioned in the xkcd article - diving and floating, being primarily about differences of density and viscosity, wouldn't change - you'd be able to dive at about the same speed as before.
Due to the law of gravity, the ball of water would have some gravity, simply due to it's mass. By Newton's shell theorem, you would have maximum gravitational attraction near the surface, and while the pressure would go up as you dived down (proportional to the ball of water's gravity), the gravity would go down. However, this effect isn't very measurable (if you want to see why, keep reading - otherwise skip to the bottom).
Assuming an unprotected body, you wouldn't be able to go very deep, or you wouldn't have a ton of water to hold this ball of water together - you really can only go down about 50m - 100m, according to the world records
A 100m radius ball of water, as Wolfram points out, is only 3 thousandths of 1% of earth's gravity - essentially nothing. Wading through this ball would be pretty much like spacewalking, but with inertial drag to stop you.
Scale the radius up by 100000 times, and you'll feel 30% of earth's gravity, (and your ball of water would stay together) but you would feel none of the variation with depth, since you can't dive very deep.
The following is multiple choice question (with options) to answer.
a person takes a dive under the sea and feels faint, with a dart stuck to them. What might have happened? | [
"they encountered a cnidaria",
"they must have startled a shark",
"they came in contact with a whale",
"they encountered the wrath of Poseidon"
] | A | poisonous darts are used for defense by sea anemones |
OpenBookQA | OpenBookQA-3800 | astronomy, telescopes
Title: Automated telescope system I am living up north in Norway, 300 km above the Arctic Circle, which gives me six months per year of darkness and cold. I used to have a starter telescope when I was living in Spain, but I gave it away, and I want to build/buy a new system with the following requirements.
operated remotely - by cables or by Wi-Fi. I want to put it outside my house - maybe even 50 meters away and stay inside (warm) and do all the stuff from my computer: moving, viewing, zooming and saving information.
I would like the telescope to know how to track a specific star or nebula
I would like to be able to do long exposures with an attached camera for faint objects, probably hours, so I can get nice images for you :)
What gear do I need and what things may I be missing? In my experience this is entirely possible in a 'warmer' climate ie southern Britain. I can give you advice on that basis, maybe someone else will advise on dealing with the cold!
Can I suggest something like the robodome, this is an automated dome to house the scope (upto 10" aperture is suitable but tight.) which can be synced to a weather station and the telescope controls.
Operating can be done fairly simply via R232 and or USB cables, the USB will need to be powered to deal with the distance. Remote operation is no different really from a wired connection while stood next to the scope.
BUT! remeber that a scope drive will have enough power to crush fingers, mains electricity is enough to kill and if something goes wrong you could a lot of equipment at the mercy of the weather. So some kind of safety plan is needed...
Minimum list: Dome, Scope, CCD, webcam, cabling, weather station, motorised mount.
[to track add a tracking camera/on ccd chip.]
Setting up your own observatory is a lot of fun though, sitting in the warm is definitely the way to go!
The following is multiple choice question (with options) to answer.
A telescope is required for detailed observation of what? | [
"mountains",
"oceans",
"clouds",
"astral bodies"
] | D | detailed observation of celestial objects requires a telescope |
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