source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2501 | Your expression for the velocity looks right; but we have to get a few other things taken care of.
First - the center of the marble doesn't move from 0 to 2R, it moves from r to 2R-r - so the potential energy due to this is smaller than mg(2R) which is what you had in your expression.
On the other hand, you need to take account of the energy of the sphere rolling (which is stated explicitly). The moment of inertia for a solid sphere (the usual case for a "marble") is
$$I=\frac25 m r^2 \\$$
$$E=\frac12I\omega^2=\frac12\frac25 m r^2 (\frac v r)^2 = \frac15mv^2\\$$
Thus your energy equation has to be corrected to
$$\frac12 m v^2 + m g (2R-2r) + \frac15mv^2 = m g h \\$$
Also - note that the marble is moving in a path with radius R-r not radius R; you need to take that into account when you compute the limiting velocity ("fast enough to stick to the track") - you have to put R-r where you have R in your velocity equation:
$$\frac{mv^2}{R-r}=mg\\ v=\sqrt{g(R-r)}$$
Combining these:
$$\frac{7}{10}mg(R-r) +2mg(R-r)=mgh\\ h = \frac{27}{10}(R-r)$$
Note that it is sometimes said that "you can ignore the rotational energy of the marble if it is very small", but that is emphatically not true - the rotational energy for a solid sphere is always 2/5 of the (linear) kinetic energy, regardless of the size of the marble. It can therefore only be ignored for the case of a (frictionless) sliding object.
Finally - since no physics problem is complete without a diagram:
This shows clearly where the R-r term is coming from.
The following is multiple choice question (with options) to answer.
A kitten curled up against a cool marble slab will | [
"heat",
"chill",
"freeze",
"starve"
] | B | as heat is transferred from something to something else , the temperature of that something will decrease |
OpenBookQA | OpenBookQA-2502 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
Which would rely on rainfall the most to sustain life? | [
"a water feature",
"a pool",
"a water park",
"a lake"
] | D | rain is a source of water |
OpenBookQA | OpenBookQA-2503 | ethology, herpetology
The 'taping the surface they are on' seems like an attempt to induce vibrations, which is a method of communication.(2)
Some chameleon species communicate with one another by vibrating the substrate that they are standing on, such as a tree branch or leaf. Animals that use vibrational communication exhibit unique adaptations in morphology (i.e., body form) that enable them to detect vibration and use it in communication. These include unique adaptations in ear and jaw morphology that give the animal direct contact with the surface they are standing on, and enable them to detect subtle vibrations. Lizards that live on substrates that can be easily moved (such as thin tree branches or leaves) are probably more likely to use vibrational communication than lizards that live on substrates that do not transmit vibrations as easily, such as the ground or thick tree trunks.
1- https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032011000400031#:~:text=The%20most%20commonly%20reported%20mating,Bull%202000%2C%20Ribeiro%20et%20al.
2- https://en.wikipedia.org/wiki/Lizard_communication
The following is multiple choice question (with options) to answer.
A lizard has young | [
"in shells",
"frozen",
"alive",
"in corpses"
] | A | reptiles lay eggs |
OpenBookQA | OpenBookQA-2504 | visible-light, atmospheric-science, sun
Title: Why is there less UV light on earth in winter? So I have often read that, at least in e.g. northern Europe, in the colder seasons, there is not enough UV (-B) light arriving from the sun, so many people have not enough vitamin-D from that.
At first I thought it was simply due to the sun "shining" for only a much shorter period of time in winter compared to summer and hence less possible exposure (not to mention that most of the skin area is covered then).
But I just had a thought coming to my mind, thinking about that in the mornings and evenings, we mostly see red light here, the higher end of the visible spectrum not getting through.
I am not familiar with the physics behind that phenomenon, but thought that the higher-end of the spectrum like the invisible UV light may not be getting through here for even longer parts of the day towards and away from high noon, and that in winter, the part of the day where UV gets through is maybe very narrow and that's why it's said not to be enough.
Is that correct? And how exactly does this work physically? The reddening of the sun has to do with Rayleigh scattering as the sun passes through more atmosphere. (see picture). This is in a sense, related to less energy but not the primary cause.
The reason we get less solar energy per square meter is that the angle of the sun in the sky affects how spread out the light is. (see updated picture). Ignoring atmospheric effects, it's the sin of the angle times peak energy. 90 degrees or directly overhead, figuring peak solar energy is 1,369 Watts per square meter (that also varies with distance), but the energy from the sun is mostly governed by the sin of the angle.
45 degrees: 1,369 * sin(45) W/m^2 or 71% of overhead or Zenith. 20 degrees above horizon, 1,369 * sin (20), just 34% of peak solar energy. Winter corresponds with the sun being lower in the sky, sunlight is more spread out. There is measurably less energy hitting the same area when the sun is low in the sky.
Passing through more atmosphere amplifies that somewhat, but the angle of the sun is the primary cause.
The following is multiple choice question (with options) to answer.
The sun shines the least when an area has | [
"precipitation",
"blue skies",
"clear skies",
"empty skies"
] | A | as the amount of rain increases in an environment , available sunlight will decrease in that environment |
OpenBookQA | OpenBookQA-2505 | the-sun, light, rotation, planetary-atmosphere
Title: Why is twilight longer in summer than winter and shortest at the equinox I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with that all year.
While doing some research for this, I noticed something that surprised me. Check out this disparity between astronomical sunrise to civil sunrise for the solstices and equinox (the latter two adjusted for daylight saving time):
Date/Astronomical/Civil/Disparity
Dec 20: 0533 - 0640 (67 minutes)
Mar 20: 0526 - 0630 (64 minutes)
Jun 20: 0320 - 0451 (91 minutes)
To be honest, these sets of ranges surprise me for multiple reasons. I clearly don't know what I don't know, but here are some questions I can formulate:
Why would twilight be longer in summer than winter? Before seeing this data, I had assumed that since the sun makes a more perpendicular path through the horizon in summer that twilight would be shorter in summer than in winter. After all, in winter the sun takes a "slanted" path across the horizon. Wouldn't the summer's path be more direct and therefore quicker?
OK: seeing this empirical evidence I conclude that something is wrong with my premise that forms my first question. Summer twilight is longer in summer than winter. However, I still would have assumed that March 20 would have had a twilight length in between the two solstices. But it's not! Why does the equinox have the shortest twilight?
Appended 5/13/2014:
I didn't want to leave my original incorrect statement in here without flagging it. As Cheekhu points out below, the sun does not follow a more perpendicular path in summer than winter, as I had erroneously assumed and stated above. See his post for more details. See this diagram,
The following is multiple choice question (with options) to answer.
A month that is in the summer in the Northern Hemisphere directly follows which month? | [
"March",
"November",
"January",
"May"
] | D | June is during the summer in the northern hemisphere |
OpenBookQA | OpenBookQA-2506 | 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.
A plant photosynthesizing will do a more efficient job it it has | [
"thirty leaves",
"ten leaves",
"six leaves",
"one leaf"
] | A | a leaf absorbs sunlight to perform photosynthesis |
OpenBookQA | OpenBookQA-2507 | geothermal-heat, open-data, mining, canada
Title: Canadian equivalent to AMLIS database? I am interested in in situ coal fires. In furtherance of this, I am hoping to find a database of Canadian mine reclamation sites, complete with incident or status reports and descriptions of specific problems.
I've poked around a very small bit in the Federal Contaminated Sites Inventory, but I'm hoping there might be something a bit more specific or targeted out there -- something more like the equivalent of the United States' Abandoned Mine Load Inventory System (AMLIS) database.
Any pointers? Try:
Federal Contaminated Sites Inventory
as well as
Crown Contaminated Sites Database (British Columbia)
Orphaned/Abandoned Mine Site Rehabilitation (Manitoba)
Abandoned Mines Information System-AMIS (Ontario)
The following is multiple choice question (with options) to answer.
Where's the best place to mine for coal? | [
"icebergs",
"jewelry store",
"lakes",
"mountains"
] | D | coal mine is a source of coal under the ground |
OpenBookQA | OpenBookQA-2508 | 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.
Light in the evening will do what as fall approaches | [
"glow longer",
"end sooner",
"last longer",
"stay later"
] | B | when the seasons change from the summer to the fall , the amount of daylight will decrease |
OpenBookQA | OpenBookQA-2509 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
If a thing is a resource which is considered renewable, it can be used | [
"once",
"endlessly",
"only three times",
"only twice"
] | B | renewable resources can be used over again |
OpenBookQA | OpenBookQA-2510 | #### Raschedian
Thank you DaveE. Your explanation clarifies things for me a lot more.
### Physics Forums Values
We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
The following is multiple choice question (with options) to answer.
which one of these individuals would have the most optimal quality of life? | [
"a doctor who sleeps six hours daily",
"a nurse who nine hours of shut eye daily",
"a student who sleeps 2 hours daily",
"a teacher who sleeps 5 hours daily"
] | B | a human requires rest to be healthy |
OpenBookQA | OpenBookQA-2511 | human-biology, physiology, proteins, amino-acids, diet
Title: Amino Acid requirement + intake in relation to diet + meat type I was arguing with a friend:
I said: The Yulin festivals cannot be condemned by western culture, as we also kill animals in equally cruel ways.
She said: It isn't just that the killing is cruel, but it doesn't help us, as humans do not derive the same essential amino acids from consuming these less traditional meats (e.g. dogs, cats, etc) like they would from consuming more traditional meats (e.g. cow, pig, goat, etc) She cites her father, a geneticist, as her source.
Question one:
Are my friend and her father correct? Does the consumption of a less traditional meat (e.g. cats, dogs, etc) provide fewer essential amino acids than the consumption of traditional meats (e.g. cows, pigs, chickens, etc)?
Question two:
My friend also made a comment about veganism and vegetarianism (I am a vegetarian), stating that for the same reason as her and her father's above comment, people who exclude meat from their diet need to use supplements. Is this correct, or would it also be possible to just vary diet to obtain these essential amino acids? There is a difference between animals in their requirements for amino acids. For example, cats need high amounts of taurine (and can't make it) and when fed diets lacking enough can go blind. This is why vegans trying to feed vegan diets to their pets can be very bad for the pet. Animal proteins have sufficient taurine for the cat.
However, the meat of a cat or dog is just as a complete source of protein for humans as any other meat. All essential amino acids are there in sufficient ratios. Suggesting otherwise by her father suggests some confusion between the dietary needs of cat vs. the nutritional value of the cat to another predator.
Your second question is easily answered by looking up essential amino acids. Wiki is plenty sufficient to get the gist Wiki Link. In short, most plants don't contain the full complement of amino acids that humans require (and can't make on their own). So to get this full complement, it requires eating multiple plant products that together contain the required amino acids.
From Harvard School of Public Health
The following is multiple choice question (with options) to answer.
If a kitten takes in nutriment | [
"it will break down",
"it will be poisoned",
"it will be energized",
"it will get sick"
] | C | nutrients are a source of energy for living things |
OpenBookQA | OpenBookQA-2512 | botany, anatomy, plant-anatomy
Title: Plant anatomy, what are these stem like filaments growing under the flower The picture below shows what I am talking about. Each flower has one and I am just wondering what they are? Looking at this, it looks like a spur. A quite overbreed one, though.
The following is multiple choice question (with options) to answer.
To see how the plant stem works, you place a rose in what? | [
"food dye",
"Fire",
"Lava",
"Metal"
] | A | a plant stem contains a system of tubes for transporting water and nutrients to other parts of the plant |
OpenBookQA | OpenBookQA-2513 | acoustics
Title: Resonance in a 1 ft granite box
I have a granite cube made using 6 slabs of granite 1 foot square and 1 inch thick. The top and bottom slabs have a 1 inch margin around the edge. The slabs are just set together, not notched or mortared or anything.
I also have a concrete block with pipes running through it that generates a sonic pulse/compression wave from a valve closing. If this were a regular water system we'd all call it water hammer. This water hammer comes out the top of the block. It is assumed that this block is not going to self destruct from the water hammer. It pulses about 60 times per minute. There is a working example of this block that I have seen online, so I know how to build it.
The following is multiple choice question (with options) to answer.
A tone is made when a hammer makes contact with | [
"a waterfall",
"air",
"an solid object",
"a log"
] | C | tapping two objects together causes the particles in those objects to vibrate |
OpenBookQA | OpenBookQA-2514 | species-identification, botany
Title: Identification of a plant Please help me to identify this plant
The plants can be found on italian balconies and I would like to buy one, but I do not know what I should look for.
The habit of the plant is trailing. This is likely to be a stone plant (Aizoaceae), depending on habit, it could well be the ice plant (Carpobrotus edulis). Stone plants are a quite diverse family of succulents from southern Africa, but are widespread throughout the western world as stabilizers of sand-dunes and in gardens as they are very tolerant of lack of watering and high salinity.
Ice plants are very common in the Mediterranean region, having become an invasive pest on much of the coastline.
If it is ice plant, then you can sub-cultivate it by taking a small part of the plant, usually leaves with a bit of stem, but even a leaf by itself may work, and placing it in water or on sandy soil. With regular watering, it should grow roots and then be plantable.
Apparently the leaves of ice plant are edible (hence the edulis part of the name), similar to Aloe I suspect.
The following is multiple choice question (with options) to answer.
The most popular plant in Italy is | [
"Air",
"Basil",
"Apple Juice",
"Metal"
] | B | plants are the source of spices |
OpenBookQA | OpenBookQA-2515 | pie. Let \$$\mathcal X\$$ be the \$$\mathbf{Cost}\$$-category where the objects are the elements of \$$\mathbb N[S]\$$ and \$$\mathcal X (x, x')\$$ is the time it takes to turn the list of ingredients described by \$$x\$$ into the list of ingredients described by \$$x'\$$ or \$$\infty\$$ if this is impossible. Some examples: $\mathcal{X}( [\textrm{flour}] + [\textrm{water}] + [\textrm{butter}], [\textrm{crust}]) = 30$ $\mathcal{X}( [2\textrm{flour}] +2 [\textrm{water}] + 2[\textrm{butter}] + [\textrm{filling}] , [\textrm{crust}] + [\textrm{pie}]) = 120$ $\mathcal{X}([\textrm{pie}], [\textrm{pie}]) = 0$ $\mathcal{X}([\textrm{water}], [\textrm{pie}]) = \infty$ Now suppose I am a busy person who prefers to buy my pie crust from the store instead of making it from scratch. Now the set of ingredients I need to make a pie is \$$T = \\{\textrm{crust}, \textrm{filling}, \textrm{pie}\\}\$$. I can create another \$$\mathbf{Cost}\$$-category \$$\mathcal{Y}\$$ where the objects are the elements of \$$\mathbb{N}[T]\$$ and \$$\mathcal{Y}(y, y')\$$ is again given by the time it takes to make transform the ingredients of \$$y\$$ into the ingredients of \$$y'\$$. Lastly we need to define a \$$\mathbf{Cost}\$$-functor \$$F:
The following is multiple choice question (with options) to answer.
Making a pie produces a | [
"chemical reaction",
"cake",
"lots of sweat",
"fear of ovens"
] | A | cooking causes a chemical reaction |
OpenBookQA | OpenBookQA-2516 | [13]:
nutrients = pd.DataFrame(
index=[
"Vitamin A",
"Vitamin B1",
"Vitamin C",
"Calcium",
"Iron",
"Phosphorus",
"Potassium",
"Total fat",
"Carbohydrates",
"Proteins",
]
)
nutrients["DRI"] = [800, 1.1, 80, 800, 14, 700, 2000, 70, 260, 50]
nutrients["Chicken Breast"] = [0, 0.1, 0, 4, 0.40, 210, 370, 0.8, 0, 23.3]
nutrients["Milk"] = [37, 0.04, 1, 119, 0.1, 93, 150, 3.6, 4.9, 3.3]
nutrients["Pasta"] = [0, 0, 0, 22, 1.4, 189, 192, 1.4, 79.1, 10.9]
nutrients["Beans"] = [3, 0.4, 3, 135, 8, 450, 1445, 2, 47.5, 23.6]
nutrients["Oranges"] = [71, 0.06, 50, 49, 0.2, 22, 200, 0.2, 7.8, 0.7]
nutrients
[13]:
DRI Chicken Breast Milk Pasta Beans Oranges
Vitamin A 800.0 0.0 37.00 0.0 3.0 71.00
Vitamin B1 1.1 0.1 0.04 0.0 0.4 0.06
Vitamin C 80.0 0.0 1.00 0.0 3.0 50.00
Calcium 800.0 4.0 119.00 22.0 135.0 49.00
Iron 14.0 0.4 0.10 1.4 8.0 0.20
Phosphorus 700.0 210.0 93.00 189.0 450.0 22.00
Potassium 2000.0 370.0 150.00 192.0 1445.0 200.00
Total fat 70.0 0.8 3.60 1.4 2.0 0.20
Carbohydrates 260.0 0.0 4.90 79.1 47.5 7.80
Proteins 50.0 23.3 3.30 10.9 23.6 0.70
The following is multiple choice question (with options) to answer.
If I wanted to get more nutrients in my body I could consume | [
"magic",
"smoothies",
"my feelings",
"my anger"
] | B | eating food is used to get nutrients by living things |
OpenBookQA | OpenBookQA-2517 | 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.
Death begins for a leaf the second it | [
"is released",
"is eaten",
"is born",
"is burned"
] | A | if a leaf falls off of a tree then that leaf is dead |
OpenBookQA | OpenBookQA-2518 | algorithms, graphs, optimization
There is one final component of your problem we have not addressed, i.e., there is a set of books $S_1$ that MUST go into box 1 and a set $S_2$ that MUST go into box 2.
Off the top of my head, I do not see a way to fix this without incorporating a source and sink $s$ and $t$ (for box 1 and 2 respectively). The formulation I've given above is almost sufficient. If $j\in S_1$ (book j MUST go into box 1), make $p_{sj}$ arbitrarily large (much more than $W$). This ensures an arbitrarily large cost will be charged if you try to but a book that must go into box 1 into box 2. Similarly, if $i\in S_2$, make $p_{jt}$ arbitrarily large.
Assuming $S_1$, and $S_2$ are non-empty (that books are already forced into each box), $W$ can be taken as 0 (since a proper partition is enforced by $S_1,S_2$) and $p_{sj}=p_{it}$ for $j\in S_1, i\in S_2$ can be as little as $\sum_{{i,j} \in N:\ i<j} p_{ij}$ (assuming each $p_{ij}\geq 0$).
The following is multiple choice question (with options) to answer.
If waste is to be avoided, then a box should be | [
"left outside",
"burned quickly",
"thrown away",
"filled repeatedly"
] | D | An example of avoiding waste is using an object more than once |
OpenBookQA | OpenBookQA-2519 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
If the ground is fully shaded, and plants there barely grow, likely the reason is | [
"water there is clean",
"people there are silly",
"oaks there are mighty",
"birds there are fat"
] | C | large trees block sunlight from reaching the ground |
OpenBookQA | OpenBookQA-2520 | philosophy
Title: Should I use anthropomorphic language when discussing AI? The English Language is not well-suited to talking about artificial intelligence, which makes it difficult for humans to communicate to each other about what an AI is actually "doing". Thus, it may make more sense to use "human-like" terms to describe the actions of machinery, even when the internal properties of the machinery do not resemble the internal properties of humanity.
Anthropomorphic language had been used a lot in technology (see the Hacker's Dictionary definition of anthropomorphization, which attempts to justify computer programmers' use of anthromporhic terms when describing technology), but as AI continues to advance, it may be useful to consider the tradeoffs of using anthropomorphic language in communicating to both technical audiences and non-technical audiences. How can we get a good handle on AI if we can't even describe what we're doing?
Suppose I want to develop an algorithm that display a list of related articles. There are two ways by which I can explain how the algorithm works to a layman:
Very Anthropomorphic - The algorithm reads all the articles on a website, and display the articles that are very similar to the article you are looking at.
Very Technical - The algorithm converts each article into a "bag-of-words", and then compare the "bag-of-words" of each article to determine what articles share the most common words. The articles that share the most words in the bags are the ones that are displayed to the user.
The following is multiple choice question (with options) to answer.
If a thing has a certain amount of itself, then it can be described using | [
"that smell",
"that color",
"that volume",
"that taste"
] | C | the volume of an object can be used to describe the size of that object |
OpenBookQA | OpenBookQA-2521 | atmospheric-chemistry
But some researchers have argued it does make a notable contribution in the lower atmosphere, but indirectly. There doesn't appear to be a consensus on how big this effect is (and the Wikipedia reference is old and obsolete). The argument for ozone being a notable contributor is based on the following. Hydrocarbon pollution in the lower atmosphere (often from vehicle emissions) leads to a variety of undesirable reactions some of which lead to the production of ozone (as well as many other irritating components of smog). We really don't want too much smog or ozone in the lower atmosphere because it is bad for health. Some have estimated that it also adds to the warming caused by hydrocarbon emissions (exacerbating the warming potential of methane, for example).
It is hard to judge the estimates of its contribution to warming not least because they rely on models of complex reactions caused indirectly by other pollutants. Also, the big issue with emissions leading to ozone are not its contribution to warming but its contribution to pollution which causes direct harm to people in the short term. In fact regulations around emissions has been striving to reduce those emissions since before we started worrying about global warming. And, many countries have sharply reduced them (this is a major reasons why most western countries insist on catalytic converters in their vehicles). We should reduce ozone pollution by reducing the other emissions that cause it and we have been doing that for decades.
I would argue that ozone is essentially irrelevant to global warming. We should strive to reduce it in the lower atmosphere even if we were not worried by global warming. So even if we can't agree on how big its contribution to warming is (which the literature isn't clear on) we should be reducing it as much as we can for more direct reasons.
And, even if we wanted to report its contribution to warming, the best place to account for it is to add it to the contribution of other emissions (eg methane) rather than to account for it separately as we don't directly emit it from anything.
The following is multiple choice question (with options) to answer.
One way we pollute could be | [
"using solar panels on the house",
"throwing plastic in the pacific",
"using plastic to make raincoats",
"using glass bottles to make a house"
] | B | pollution is a source of pollutants |
OpenBookQA | OpenBookQA-2522 | trees, forestry
Title: Why do some trees hold their leaves through fall and winter? Why do some species of oak (Quercus spp.) retain their leaves through fall and winter? I've found that these leaves are called marcescent leaves. There must be some benefit that the tree gains from this because it seems like it would increase the possibility of limb damage due to snow accumulation on the leaves. The trait might not necessarily allow for an advantage, but a few possibilities have been proposed:
Nutrient return to the soil when needed in the spring
Less palatability to grazing animals
Source:
http://northernwoodlands.org/articles/article/why-do-some-leaves-persist-on-beech-and-oak-trees-well-into-winter
The following is multiple choice question (with options) to answer.
When an oak leaf falls to the ground, it is because of | [
"heavy poetry",
"air mass interaction",
"wishful thinking",
"the moon's gravity"
] | B | pushing an object requires force |
OpenBookQA | OpenBookQA-2523 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
A seed is dispersed when it is | [
"inside the original plant",
"beneath the original plant",
"away from the original plant",
"in the original plant"
] | C | seed dispersal is when the seeds of a plant are moved from the plant to a new environment |
OpenBookQA | OpenBookQA-2524 | cooling
Title: A question about cooling (related to a question asked by someone else) It's a simple question, but this post asking why it is that tea cools faster when it is evenly divided into two different cups, made me wonder if it's a similar case for solid food. An answer to the tea question is that the tea cools mostly by evaporation, and that there is more surface area after it has been divided.
Sometimes when I'm trying to get a batch of food to cool down, I split it into several containers because I know it will cool down more quickly than if it had remained in one large pot. I figured that it has something to do with an increase in surface area, but is there also a similar evaporation effect that happens with solid food? Heat is lost by one or more of three methods, radiation, conduction or convection. Evaporation, to me would be convection, heating the air and it rises up and away, cooling air coming in to replace it and the temperature of the food drops.
So food heat can be lost, probably mostly by a bigger surface area, (conduction) as with the tea in two or more cups to increase the surface area and by evaporation/convection as above, or, especially if its really hot, by radiation.
You probably most likely will feel radiation loss when you open a hot oven door, less likely as a heat loss source with food, if it's that hot, it's probably burnt beyond hope:).
The following is multiple choice question (with options) to answer.
A cup of hot tea next to a glass of iced tea will make which become colder? | [
"cup of noodles",
"the hot tea",
"the iced tea",
"tee in alphabet"
] | B | as heat is transferred from something to something else , the temperature of that something will decrease |
OpenBookQA | OpenBookQA-2525 | food, nutrition, energy-metabolism
Title: What are the bare minimum nutrients required to survive as a human? I am trying to determine the bare minimum nutritional requirements to survive as a human, ignoring energy (caloric) requirements. Another way to ask this question is: What elements can humans not live without? I am not inquiring solely about what nutrients are needed, but also their approximate amounts.
Imagine pills that a person can take that covers all their base nutritional needs and that after taking this pill the person can eat whatever they want to meet their caloric requirements. Hypothetically, this pill could have some amount (how much?) fat, carbohydrates, protein, fiber, minerals, and vitamins, and the person could subsequently eat any other food to meet their caloric requirements knowing their nutritional needs would already be otherwise met. Lets ignore the possibility of the person suffering from health issues due to eating too much of any specific food to meet their caloric requirements (e.g., taking the magic pills and then eating only butter).
A person in this situation could think "Ok I've got most of my bases covered, now I just need to ingest another 1000 calories of (almost) anything I want).
What nutrients are absolutely necessary for humans to survive indefinitely, and how much of these nutrients are required?
I am hoping for a complete list with approximate amounts (e.g., 20g fat, 20g carbohydrates, 1mg Vitamin X, .05mg Vitamin Y, 10mg mineral X). Essential nutrients include (NutrientsReview):
Water
9 amino acids: histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, tryptophan, threonine, valine
2 fatty acids (alpha linolenic and linoleic acid)
Vitamins: A, B1, B2, B3, B5, B6, folic acid, biotin, B12, C,
D, E and K (and choline, which is considered a vitamin-like substance)
Minerals: calcium, chromium, chloride, copper, iodine, iron,
manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc
The following is multiple choice question (with options) to answer.
Which can is depleted permanently? | [
"bright sunlight",
"corn",
"polluted water",
"coal"
] | D | fossil fuels are a nonrenewable resource |
OpenBookQA | OpenBookQA-2526 | # Is there no solution to the blue-eyed islander puzzle?
Text below copied from here
The Blue-Eyed Islander problem is one of my favorites. You can read about it here on Terry Tao's website, along with some discussion. I'll copy the problem here as well.
There is an island upon which a tribe resides. The tribe consists of 1000 people, with various eye colours. Yet, their religion forbids them to know their own eye color, or even to discuss the topic; thus, each resident can (and does) see the eye colors of all other residents, but has no way of discovering his or her own (there are no reflective surfaces). If a tribesperson does discover his or her own eye color, then their religion compels them to commit ritual suicide at noon the following day in the village square for all to witness. All the tribespeople are highly logical and devout, and they all know that each other is also highly logical and devout (and they all know that they all know that each other is highly logical and devout, and so forth).
[For the purposes of this logic puzzle, "highly logical" means that any conclusion that can logically deduced from the information and observations available to an islander, will automatically be known to that islander.]
Of the 1000 islanders, it turns out that 100 of them have blue eyes and 900 of them have brown eyes, although the islanders are not initially aware of these statistics (each of them can of course only see 999 of the 1000 tribespeople).
One day, a blue-eyed foreigner visits to the island and wins the complete trust of the tribe.
One evening, he addresses the entire tribe to thank them for their hospitality.
However, not knowing the customs, the foreigner makes the mistake of mentioning eye color in his address, remarking “how unusual it is to see another blue-eyed person like myself in this region of the world”.
What effect, if anything, does this faux pas have on the tribe?
The possible options are
Argument 1. The foreigner has no effect, because his comments do not tell the tribe anything that they do not already know (everyone in the tribe can already see that there are several blue-eyed people in their tribe).
Argument 2. 100 days after the address, all the blue eyed people commit suicide. This is proven as a special case of
The following is multiple choice question (with options) to answer.
Suzy's friends call her Bigfoot, who can she likely blame for this? | [
"her parents' intentions",
"her parents' genes",
"learned traits",
"her past life"
] | B | genes are a vehicle for passing inherited characteristics from parent to offspring |
OpenBookQA | OpenBookQA-2527 | evolution, species
Title: Reasons why living fossils exist?
A living fossil is a living species (or clade) that
appears to be similar to another species otherwise known only from fossils,
typically with no close living relatives.
A living fossil is considered as a successful organism, which has made its way through many major extinction events. Also, the morphology of living fossils resemble some species of organisms which we know only through their fossil remains.
What is the reason for a particular type of species to become a living fossil; is the engineering of this particular species extraordinary, in that it can survive any selection process encountered thus far?
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Have these organisms modified themselves, so that currently their morphology seems to be similar to a fossil organism? One part of your question betrays a serious error:
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Actually the reverse is true; constancy of form can only be maintained in the presence of continuous selective pressure. It's just that this is stabilising selection that acts to maintain the existing form rather than push the organism to new morphologies. In fact, most selection acts in this manner. This shouldn't surprise you: organisms are typically well adapted to their environments so changes are more likely to reduce fitness than increase fitness.
It's also worth noting that although living fossils show little morphological change they can continue to show change at the molecular level at rates as high as, or higher than, other organisms - e.g. (May et al 2007; Cao et al 2013).
The following is multiple choice question (with options) to answer.
A thing that now exists in fossilized form that can be put together to take a full shape is | [
"extinct theories",
"ancient beings",
"huge needles",
"large beans"
] | B | An example of a fossil is the bones of an extinct animal |
OpenBookQA | OpenBookQA-2528 | heat-transfer, energy-efficiency, heat-exchanger, engines, diesel
Cat has a nice engineering primer on engine cooling - http://s7d2.scene7.com/is/content/Caterpillar/CM20160713-53120-13199
Vehicles often use air-to-air aftercooling and oil cooling, so the aftercooler and oil cooler heat doesn't end up in the radiator. Most larger engines use jacket water for aftercooling and oil cooling, so you need to add those values to the internal jacket water heat to size the radiator.
Cat 3412 genset technical data sheet (see section titled heat rejection on page 2)
I'll try to dig up a similar sheet for mobile equipment engines later. Or someone else can ;)
The following is multiple choice question (with options) to answer.
When would you want a radiator the most? | [
"winter",
"spring",
"fall",
"summer"
] | A | a radiator is a source of heat |
OpenBookQA | OpenBookQA-2529 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
If a person wants to save the environment, a thing they can try is | [
"using more Styrofoam",
"buying more stuff",
"reusing plastic dishware",
"burning more plastic"
] | C | An example of protecting the environment is reducing the amount of waste |
OpenBookQA | OpenBookQA-2530 | climate, solar-terrestrial-physics
Title: Why is March colder than September in Northern Hemisphere? Forgive my ignorance of the subject but I was always wondered about the exact reason of this phenomenon.
Vernal equinox happens around March 20, whereas autumnal equinox happens around September 22, so wherever you are in Northern Hemisphere, the length of the day, and consequently the amount of solar energy that reaches the place should be almost the same.
However the average temperatures differ widely, for example Toronto has average temperatures of 2°C to 6°C on March 20th, and 14°C to 19°C on September 22nd. So around 12°C difference [link].
So obviously there is some sort of temperature inertia, as temperatures seem to experience a delay in responding to changes in day length.
What is the main reason for it? Is it effect of sea ice or snow-covered land albedo? Energy stored in oceans? Energy absorbed by melting snow and ice? The phenomenon is called seasonal lag.
There's a more extensive answer elsewhere on this site but the basic idea is that temperature lags behind insolation by several weeks, because it takes time to change the mean temperatures of the land, the atmospehere, and especially oceans change their mean temperature. This diagram tries to show the lag, along with various ways of reckoning the seasons:
The following is multiple choice question (with options) to answer.
You are shivering and see flurries; you remember that you are in the Northern Hemisphere. What day is it most likely? | [
"the autumnal equinox",
"the vernal equinox",
"the summer solstice",
"the winter solstice"
] | D | the winter solstice is on December 21st in the northern hemisphere |
OpenBookQA | OpenBookQA-2531 | oceanography, rivers, satellite-oddities
Title: What are these river/canyon-like carvings in the ocean? Browsing around Google Maps, I came across this off the south-west coast of Ireland
It looks very consistent with the shape rivers and their tributaries might make, but it has me puzzled since it's all underwater!
The main, most "river-like" one is in the middle-left of the picture but there are more (which look more like fjords) at the bottom.
What caused this feature? The carvings are submarine canyons, a part of the continental slope leading from the continental shelf to the continental rise and ultimately the Abyssal plains. They are a product of :
erosion through currents and
slumping of the continental shelf
Like other erosive or slumping effects, they can be self-reinforcing, leading to canyon-like structures. The highlighted canyon here is the Gollum Channel system, seen here.
The following is multiple choice question (with options) to answer.
Which was happens most near canyons | [
"the moon",
"whales",
"riverflow",
"fear"
] | C | most canyons are formed by flowing rivers through erosion over long periods of time |
OpenBookQA | OpenBookQA-2532 | inorganic-chemistry, physical-chemistry, materials
The geometric simplicity of your custom part, however, suggests that you could cut it from a plastic sheet, obviating molding and the potentially expensive equipment that goes with it.
The following is multiple choice question (with options) to answer.
You might recycle plastic by creating | [
"happiness",
"love",
"beanies",
"the sun"
] | C | An example of recycling is using an object to make a new object |
OpenBookQA | OpenBookQA-2533 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
a tree felling bulldozer goes through a wooded area, leveling it down, what happens to the trees in the ground? | [
"they will become taller",
"they will grow stronger",
"they will thrive and rise",
"they will perish right there"
] | D | if a tree is cut down then that tree will die |
OpenBookQA | OpenBookQA-2534 | thermodynamics, visible-light, lenses
I forgot to mention that you can't heat the sample beyond about $5500\,K$ (which is the temperature of a black body that best fits the spectrum we receive at sea level). Of course, you need to know what you're doing to get anywhere close to this temperature.
The following is multiple choice question (with options) to answer.
A source of heat might be | [
"rubbing noses",
"swimming in Antartica",
"touching ice",
"sitting in freezers"
] | A | a car engine is a source of heat |
OpenBookQA | OpenBookQA-2535 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
Jack rabbits move very fast to avoid | [
"squirrel",
"mice",
"snails",
"hawks"
] | D | some animals move quickly to escape predators |
OpenBookQA | OpenBookQA-2536 | evolution, biochemistry, plant-physiology, plant-anatomy, life
Title: Plants without bacteria? is it theoretically possible? I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But it is a natural way.
But is it possible to have a world with plants (without mammals or microorganisms and without bacteria) that could exist in the long term. Saying the atmosphere of these world has already enough nitrogen, oxygen and CO2, and of course there is water.
What could break this artificially created world with such conditions (say the world created not from low-level living structures)?
Could bacteria emerge in the world? This is the sort of question that should be considered from more than one perspective. Since this is speculation, take it as a given that there is a lot of 'what if' here.
I doubt most animals and plants can do entirely without bacteria - as you say most of the essential nutrients come from bacteria, who fix nitrogen. If only plants were left on earth, eventually the plants would use up all the nitrogen and they would have to find a way to fix more.
Can bacteria emerge from just a world of plants? I don't think viruses arise spontaneously, but since genomes often have viruses embedded in them, over the course of a billion years or so, its possible since bacteria and viruses continue to be impressed upon our genomes. Would it happen in time? Most would be skeptical whether that timing could work out.
In practice it would be hard to create a world like this. I would be interested to see whether you could sterilize the microorganisms off of seeds without killing the plant for instance. If you're asking about a small sterile environment with only plants, you could do it by adding the nutrients the plants need and giving them sunlight. Such self sustaining systems have been made with cyanobacteria and i'd be surprised if plants could not be included. But these are closed systems and judged by limited amounts of time, so whether this is an answer to your question is not clear. Here it looks like some water plants and fish have been done. If there was a plant that created CO₂ at an adequate rate its possible.
The following is multiple choice question (with options) to answer.
Plants are unable to grow without soil because soil is where the plants get their | [
"TV shows",
"sustenance",
"friends",
"candy"
] | B | soil contains nutrients for plants |
OpenBookQA | OpenBookQA-2537 | 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.
If a plant is in an environment with a lot of oxygen, and then oxygen levels very slightly drop, the plant will | [
"understand",
"sour",
"calibrate",
"pray"
] | C | changes in an environment cause plants to adapt to survive |
OpenBookQA | OpenBookQA-2538 | 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.
Seasons occur because long ago something huge slammed into our planet and now its axis is | [
"lazy",
"jaded",
"slanted",
"stilted"
] | C | Earth 's tilt on its axis causes seasons to occur |
OpenBookQA | OpenBookQA-2539 | meteorology, weather-forecasting, barometric-pressure
Title: Do high pressure systems draw air towards them? I refer to the this very recent article, which quotes Andrew Watkins (Manager of Climate Prediction Services at the Australian Bureau of Meteorology).
My understanding has always been that air flows away from high pressure towards lower pressure, so the following quote from the referenced article confuses me. Can anyone explain it for me?
"There's been a big high pressure system drawing air in off the ocean,
keeping it a bit cooler for Sydney," Dr Watkins said. As Fred said, it's just an unfortunate word choice that makes you think the professor is suggesting air flows towards the high.
Indeed, a surface high pressure south of Sydney would be the circumstance to have the air circulate around it in such a way as to "draw" air onshore from off the shore... even as it's actually really flowing somewhat away from the high.
There's a long-range model forecast showing exactly this setup building after a strong low potentially passes by this week... and so Sydney may be held cooler again just in time for Boxing Day:
from www.pivotalweather.com
(This is only one model's long-range forecast, and the skill in such forecasts is quite low. I present it to show this scenario, not to make any forecast as to whether it'll actually happen next week)
You can see the green arrows are bringing air onshore. This link suggests current ocean surface temperatures are around 23°C (73°F). So that would likely reduce the temperature slightly (if you explore the plots at pivotalweather.com for Australia, it currently shows a forecast high closer to 23°C for the day, rather than nearer the 30s many spots in the area see tomorrow).
The following is multiple choice question (with options) to answer.
It's June in Australia so I should make sure to wear | [
"mittens",
"shorts",
"flip flops",
"a bathing suit"
] | A | June is during the winter in the southern hemisphere |
OpenBookQA | OpenBookQA-2540 | D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E. _________________ MathRevolution: Finish GMAT Quant Section with 10 minutes to spare The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy. "Only$79 for 1 month Online Course"
The following is multiple choice question (with options) to answer.
Which of the following will most likely to be true? | [
"focused light beams like lasers can endanger pilots",
"napkins can endanger pilots",
"sweaters can endanger pilots",
"teddy bears can endanger pilots"
] | A | a laser is used for producing light |
OpenBookQA | OpenBookQA-2541 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
A deer would prefer to eat | [
"Metal",
"Cucumbers",
"Pigs",
"Chalk"
] | B | a deer lives in a forest |
OpenBookQA | OpenBookQA-2542 | 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.
If a sand grain is in a tree house unexpectedly, a likely culprit responsible for its movement is | [
"ghosts",
"gales",
"spirits",
"angels"
] | B | wind carries sand from one place to another place |
OpenBookQA | OpenBookQA-2543 | pressure, friction, material-science
Now we have a triaxial compressive stress state. If all stresses were equal, there would be no plastic deformation. But as the friction forces have a limit, the vertical stress increases until the difference to the horizontal stress is enough to deform the material (or break the roll...). That is the reason for the friction hill.
The following is multiple choice question (with options) to answer.
A load of dirt, mud, water and debris can come toppling down from a higher place if | [
"skies are clear",
"cats are playing",
"leaves are budding",
"weather is poor"
] | D | storms can cause a landslide |
OpenBookQA | OpenBookQA-2544 | death, kidney
Title: For how long can a person drink sea water? How long could a person of lets say 18 years be able to drink sea water without getting too much into trouble ? Or can a person drink it without noticing that it is a very bad idea ? I don't mean in just 1 drink session but like can one manage a day or two ? Can one drink it and go to sleep and be still healthy (although very thirsty) in the morning ?
(this is just a hypothetical question, I'm not a scientist at all, I'm not sure what tags to use actually)
Additional brainstorming:
kidney failure
any other organ failure
dying of thirst
...
(source: free.fr)
Alain Bombard
He is a french biologist who voluntarily tested how many days a man can survive drinking seawater and how?
Biologist point of view
Sea contains ~3.5% of salt$^1$. Our kidney separates the waste from water and excrete them in urine provided the salt content is less than ~2%.$^2$
So, it will take the water already present in the body. Causing excessive thirst and dehydration, eventually cause death.
Alain's Experiment
Just one spoon of seawater at 20 minute intervals, drinking very
slowly and letting the saliva in your mouth reduce the saline in the
water you have swallowed.
Though he survived 65 days (From and including: Sunday, 19 October 1952
to Tuesday, 23 December 1952, ~4,400km) of his journey and lost 25 kg of weight, this result is never successfully reproduced.
Source:
http://oceanservice.noaa.gov/facts/whysalty.html
http://paradise.docastaway.com/drinking-sea-water
The following is multiple choice question (with options) to answer.
If someone is dying of liquid needs, they can hydrate the body by | [
"high temp snow",
"catching falling ash",
"visiting a valley",
"pray"
] | A | snow falls during the winter in some environments |
OpenBookQA | OpenBookQA-2545 | fracking, clathrates
Title: Do we know how large deposits of methane clathrates were formed in permafrost regions? We can see that there are large buildups of methane clathrates in permafrost regions. This seems different to the buildups of natural gas which fracking releases, which appear to have just come from escaped gases from oil/coal deposits.
My question is: Do we know how large deposits of methane clathrates were formed in permafrost regions? Rotting vegetation generates methane, or marsh gas as it is sometimes called. The most obvious method by which clathrates were formed in Arctic regions is that many years ago during summer and autumn, rotting vegetation produced methane, which combined with water at cold temperatures to produce methane ice, otherwise known as clathrates. Extremely cold temperatures are not necessary to form clathrates. They form at the bottom of deep seas, where the temperature even in the tropics is a constant 4 or 5 C. There are huge deposits of clathrates on the deep ocean floor, and there has been talk of exploiting them commercially.
A theory to explain the Permo-Triassic extinction event of 250 million years ago hypothesises that super-eruptions in the Siberian Traps super-volcano raised temperatures enough to release vast quantities of methane from tundras and ocean beds, so that with the additional greenhouse gas the average temperature rose by about 10 C, causing the extinction of nearly 90 percent of all large animals, a greater mass extinction than the better known event at the end of the Cretaceous.
The following is multiple choice question (with options) to answer.
Natural gasses have been created by | [
"years of dead things changing composition",
"years of muddy waters churning",
"years of growing bananas",
"years of pickled flowers"
] | A | heat and pressure change the remains of prehistoric living things into natural gas |
OpenBookQA | OpenBookQA-2546 | programming, qiskit
Which will output:
┌───┐
q_0: ┤ X ├
└───┘
┌───┐┌─────┐┌───┐
q_0: ┤ H ├┤ qc1 ├┤ Z ├
└───┘└─────┘└───┘
New circuit with controlled:
q_0: ───■───
┌──┴──┐
q_1: ┤ qc2 ├
└─────┘
Decomposed new circuit:
┌────────┐ »
q_0: ┤ P(π/2) ├──■───────────────────■───────────────────────────■──»
├────────┤┌─┴─┐┌─────────────┐┌─┴─┐┌──────────┐┌─────────┐┌─┴─┐»
q_1: ┤ P(π/2) ├┤ X ├┤ U(0,0,-π/2) ├┤ X ├┤ U(0,0,0) ├┤ RY(π/4) ├┤ X ├»
└────────┘└───┘└─────────────┘└───┘└──────────┘└─────────┘└───┘»
« ┌──────┐ »
«q_0: ──────────────■──┤ P(0) ├──■────────────────■────────────────■──»
« ┌──────────┐┌─┴─┐├──────┤┌─┴─┐┌──────────┐┌─┴─┐┌──────────┐┌─┴─┐»
«q_1: ┤ RY(-π/4) ├┤ X ├┤ P(0) ├┤ X ├┤ U(0,0,0) ├┤ X ├┤ U(0,0,0) ├┤ X ├»
« └──────────┘└───┘└──────┘└───┘└──────────┘└───┘└──────────┘└───┘»
« ┌────────┐
«q_0: ┤ P(π/2) ├──■───────────────────■──────────────
« ├────────┤┌─┴─┐┌─────────────┐┌─┴─┐┌──────────┐
«q_1: ┤ P(π/2) ├┤ X ├┤ U(0,0,-π/2) ├┤ X ├┤ U(0,0,0) ├
« └────────┘└───┘└─────────────┘└───┘└──────────┘
The following is multiple choice question (with options) to answer.
a closed circuit | [
"is turned off",
"is uninterrupted",
"has multiple paths",
"incomplete"
] | B | a closed circuit has continuous path |
OpenBookQA | OpenBookQA-2547 | species-identification, botany
Title: Can you identify this (possibly waterstoring) plant? My son brought home a sapling, and after 4 years in a pot it is now about 30 cm or a foot high (from the "ground" to the top of the "stem"). It doesn't need a lot of water and can go weeks without being watered, in fact it seems to me as if it is storing water in the thicker upper part of its stem. When I water it "too much", new leaves start to grow. There are tiny "blossoms" along the stem, and every now and then small, dark brown, spherical seeds about 2 mm in diameter pop out from the "blossom" and are thrown across the room as far as a meter (about a yard) or two.
What plant is this?
I believe that it is not native to my European home but some kind of decorative plant imported and sold through a florist or imported privately, but I'm not sure. It is an Euphorbia leuconeura (Madagascar Jewel), which is native to Madagaskar. The leaves and the thick (waterstoring) stem with a narrow base is very typical.
The plant is cool in the sense that it easily produces seeds (also as potted) which it can shoot away from the plant. I've had it myself and you can sometimes hear seeds hitting the window or floor. Even if it is easy to grow and to reproduce it is actually considered threatened in its native habitat (IUCN Red-listed as Vulnerable) due to habitat loss
The flowers are very small and found directly on the stem, see below:
(picture from Wikipedia)
The following is multiple choice question (with options) to answer.
Teak can be found in | [
"glacier sheets",
"blue songs",
"groves",
"underwater trenches"
] | C | if something is a raw material then that something comes directly from a source |
OpenBookQA | OpenBookQA-2548 | environmental-protection, natural-disasters
Title: The impact of red mud near Hamburg On October 4, 2010 a disaster started at a site in Ajka, Hungary. A red mud reservoir near an alumina plant broke, and the toxic material moved through nature and on into the northern half of Devecser village and killed 10 people, injured 406 others, and destroyed a lot of trees and animals.
I calculated the area of that reservoir to be about 25 hectares using this site.
Also, I calculated the maximum length and width of the flown red mud to be about 3 miles and 1 mile respectively (using Google Maps).
On the Wikipedia page for the Ajka disaster it's also stated that the volume of red mud was about 1,000,000 m$^3$, and the total area affected was about 40 km$^2$.
That got my attention looking at a red mud reservoir near Hamburg. It has an area of about 1.45 km$^2$, and it is 28 miles far from Hamburg. Also, it's near an alumina plant in Stade.
The following is multiple choice question (with options) to answer.
Loss of resources has a negative impact on what in an area? | [
"weather",
"sunlight",
"critters",
"organism diagrams"
] | C | loss of resources has a negative impact on the organisms in an area |
OpenBookQA | OpenBookQA-2549 | electrostatics, electricity, water, everyday-life, air
Title: The Ultimate Hand Dryer I have come across many hand dryers that attempt to dry your hands really fast after you wash them. Here are two of them:
XLERATOR
http://www.exceldryer.com/
Dyson Airblade
http://www.dysonairblade.com/homepage.asp
So I guess I have a ridiculously high standard cause I think even these are too slow.
Would it be possible to create a large static electric field to attract the water molecules off of your hand? Can someone offer some ideas that would remove the water off of your hand using some type of electric field generated by charged plates or something? Water molecules don’t carry an electric charge (and if they do, you don’t want them on your hands…). The dipole moment of water molecules can only be used to rotate them in space, not to move them. Additionally, the forces that apply to water molecules on your hands also apply to water molecules in your hands. So even if you somehow managed to apply a sensible force on these water molecules, this would get rather uncomfortable. The same problem arises if you attempt to heat them up by means of electric resonance (similar to a microwave).
I therefore doubt that it would be possible to build a device based on electric fields rather than moving air, that removes water molecules from the surface of your skin.
However, it might be possible to vaporise the water on your hands using strong infrared lamps. This might lead to other problems, though, such as the focusing of infrared radiation on small areas of the skin by water drops.
The following is multiple choice question (with options) to answer.
What is going to become dryer faster? | [
"A wet shoe outside",
"A wet cloth in the fridge",
"A wet cloth in the dirt",
"A wet cloth under shade"
] | A | the sun causes water to evaporate more quickly by adding heat |
OpenBookQA | OpenBookQA-2550 | np-complete, reductions, satisfiability, integer-programming
Convert these two circuits to CNF, filling in the $a_{1j}$ variables and $b_1$ since they are given.
Repeat for all rows, but reuse the $x_j$ variables between them.
Take all the comparison bulbs and AND them together to get a single lightbulb as output. The SAT problem would now be "what inputs for all $x_j$ will make this final ANDed lightbulb light up"
The final CNF will contain all the constraints.
The following is multiple choice question (with options) to answer.
Which would likely require completing a circuit to play? | [
"tic tac toe",
"ping pong",
"hide and seek",
"PONG"
] | D | when an electrical conductor is plugged into an outlet , a circuit is completed |
OpenBookQA | OpenBookQA-2551 | botany, marine-biology, salt
Title: Mangroves and desalination of sea water I am not an expert but I guess that mangroves (or some other plants that thrive in sea water) perform some kind of desalination to extract fresh water from sea water.
Is this true? If yes, What biological mechanisms are used to remove salt from sea water?
I am interested in any research about biological desalination. This paper might be of interest to you: https://advances.sciencemag.org/content/6/8/eaax5253.
The researchers created a synthetic mangrove that actually performs desalination, using the principles of natural mangroves.
The introduction has a good overview of the main ways mangroves desalinate saline water, namely:
Physical blockage by suberin within cells walls
Selective permeability of cell membranes in root
Negative pressure caused by evaporation that acts as hydraulic pressure to cause take-up of water by roots
All these combine to turn the mangrove into a kind of natural RO (reverse osmosis) machine.
The following is multiple choice question (with options) to answer.
Desalinating water from the ocean does what to nearby fish? | [
"manipulates habitat",
"makes habitat nicer",
"helps them out",
"gives them money"
] | A | fish lay eggs |
OpenBookQA | OpenBookQA-2552 | newtonian-mechanics, momentum, conservation-laws, projectile, everyday-life
Title: When you hit a baseball, does the ball ever travel faster than the bat? It seems impossible, yet I'm thinking that maybe because the ball compresses against the bat a bit it acts a little like a spring, and DOES travel faster than the bat?
The following is multiple choice question (with options) to answer.
Bats might use what to get home | [
"a map",
"time travel",
"their voice",
"their magic"
] | C | bats can echolocate |
OpenBookQA | OpenBookQA-2553 | evolution, species
Title: Reasons why living fossils exist?
A living fossil is a living species (or clade) that
appears to be similar to another species otherwise known only from fossils,
typically with no close living relatives.
A living fossil is considered as a successful organism, which has made its way through many major extinction events. Also, the morphology of living fossils resemble some species of organisms which we know only through their fossil remains.
What is the reason for a particular type of species to become a living fossil; is the engineering of this particular species extraordinary, in that it can survive any selection process encountered thus far?
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Have these organisms modified themselves, so that currently their morphology seems to be similar to a fossil organism? One part of your question betrays a serious error:
Is there not enough selection pressure exerted on this species in order to force it to change morphologically?
Actually the reverse is true; constancy of form can only be maintained in the presence of continuous selective pressure. It's just that this is stabilising selection that acts to maintain the existing form rather than push the organism to new morphologies. In fact, most selection acts in this manner. This shouldn't surprise you: organisms are typically well adapted to their environments so changes are more likely to reduce fitness than increase fitness.
It's also worth noting that although living fossils show little morphological change they can continue to show change at the molecular level at rates as high as, or higher than, other organisms - e.g. (May et al 2007; Cao et al 2013).
The following is multiple choice question (with options) to answer.
An example of a fossil could be a | [
"dino track",
"animal eye",
"human heart",
"abandoned nest"
] | A | a nest is made of branches |
OpenBookQA | OpenBookQA-2554 | evolution, homework
Title: Can someone help me analyze this article? I need to read this article — "Beyond the rainbow" by
Marie-Claire Koschowitz et al., for an exam.
Following are some questions for which I could not figure the answer out after reading.
1) Why does this miniaturization necessitates insulation ? Following is quote from article: "For fast-growing, presumably warm- blooded animals , such miniaturization would only have been possible with sufficient body insulation. "
2) Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ? Why does the article mention reptiles before that ? Are birds reptiles ?
3) The article starts talking about how mammals develop fur and lost their highly differentiated color vision because they gave up structural color signaling. What is the direct connection between mammals and the dinosaurs ? I don't see the parallel here....why bring the mammals into the discussion ?
4) What is the connection between pennaceous feather and planar feathers ?
Any or all questions answered is welcome ! Thanks ! I will answer the questions one by one-
Why does this miniaturization necessitates insulation ?
An organism's volume determines the total amount of heat that can be stored. The loss (exchange) of heat between the body and external environment mainly occurs on the skin's surface. Hence, body volume determines how much heat is stored, while body surface determines how fast that heat is dissipated to the environment. Volume increases with a power of three with radius, while surface increases with a power of two. Hence, smaller animals have large surface-to-volume ratios, which decreases rapidly with body size. Hence, small animals will dissipate relatively more heat per unit of time.
Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ?
No, birds are the closest living relatives to dinosaurs, and birds can be said to have inherited tetrachromacy from dinosaurs - see the cladogram below.
The following is multiple choice question (with options) to answer.
If a creature is building a soft space for sitting and roosting, it is likely | [
"a chickadee",
"a rabbit",
"a ferret",
"a dog"
] | A | birds build nests in the spring |
OpenBookQA | OpenBookQA-2555 | the-moon
But, arguably, it's still less red than a sunset. Why is the moon's reddening less obvious than the sun's?
The moon is already a little reddish
I think it's important to think about what 'reddening' means. You said "the spectrum of moonlight is more redshifted than that of the sun, which should contribute to an even more intense reddening" -- but that's actually the opposite of the case. (I would not use the term "red shift" in this context; that term has a specific astronomical meaning related to relativistic speeds.)
The sun at the horizon turns red because the blue light is being scattered by the atmosphere (contributing to blue skies for the day side of the world), and the red passes straight through. Consider if the sun produced only red light -- then you would see no additional reddening near the horizon because there's no blue light to remove from it.
So if the moon's spectrum is already redder than the sun's, then we would expect its reddening to be less intense than the sun's, not more -- there's not as much blue light to remove, so the change is smaller. The moon may be as red or redder than the sun from an objective "I am measuring light frequencies" perspective, but if you take two moon photos, one at the horizon and one high in the sky, and lay them side by side, the difference will be less impressive.
How red is the sun, really?
In your question you state that the sun "turn[s] bright red when it's close to the horizon", but I don't think that's true. Not every sunset features a really red sun; a middling orange is far more common. The deep crimson is usually something you usually only see when there's a lot of particulate in the atmosphere, such as from a volcanic eruption or large fire. So I don't think the sun's color shift is as dramatic as you think, and thus the moon's less dramatic color shift matches it more closely than you're expecting. The moon does indeed turn a deep blood red when the atmospheric conditions are right for it.
The following is multiple choice question (with options) to answer.
Why is that tulip red? | [
"it's embarrassed",
"it's really yellow",
"it's sick",
"genetics"
] | D | the colors of the parts of an organism are inherited characteristics |
OpenBookQA | OpenBookQA-2556 | genetics, vision
Females who are heterozygous for red and green pigment genes that encode three
spectrally distinct photopigments have the potential for enhanced color vision, as they are effectively tetrachromats (Deeb, 2005, Neitz et al., 1991). However, sensitive color-contrast testing on 43 tetrachromats has revealed that most of these females have no deviating color-discrimination whatsoever. 8 subjects showed relatively small effects, while only one showed a clear increased sensitivity in a narrow range of frequencies. It is believed that the human visual system is not plastic enough to cope with the extra spectral input. In fact, in the group there was an overall increase in error rates on some color tests (pseudoisochromatic plates, and Nagel anomaloscope color matching) (Jordan & Mollon, 1993).
In New World Monkeys, however, the situation is different. Squirrel monkeys are basically a dichromatic species, but two-thirds of the females are heterozygous, and gain trichromatic vision by expressing two of three possible alleles coding for pigments in the middle- to long-wave range of the spectrum. X-chromosome inactivation serves to segregate the alternative allelic products in different subsets of cones. The visual system of the heterozygous female is apparently plastic enough to take advantage of the presence of three classes of cone, because heterozygous monkeys have enhanced color selectivity in the red-green range that are impossible for all males and for homozygous females. This advantage perhaps enables the heterozygote to judge better the ripeness of fruit, or to find fruit or conspecifics (Jordan & Mollon, 1993).
Note that the emergence of trichromacy in humans and some other primates was the result of the red/green gene duplication. Trichromacy in primates was evolutionary selected for likely because of the enhanced capability to discern (ripe) fruits (Lucas et al., 2003). It has nothing to do with sex-differences, because not many human females benefit from tetrachromacy in terms of enhanced color vision.
References
- Deeb, Clin Genet (2005); 67: 369–377
- Jordan & Mollon, Vis Res (1993); 33(11): 1495-1508
The following is multiple choice question (with options) to answer.
Scandinavian eye color testifies to | [
"genes have little effect at all on eye color",
"dominant alleles are more common there",
"recessive genes being more common there",
"Thor's Hammer causes it to be so"
] | C | when both a dominant and recessive gene are present , the dominant trait will be visible |
OpenBookQA | OpenBookQA-2557 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
Weathering can do what? | [
"change a sculpture to dust",
"build a steel city",
"travel to space on air",
"create a time traveling vortex."
] | A | An example of weathering is when a plant root grows into a crack in rock |
OpenBookQA | OpenBookQA-2558 | physiology, muscles
Title: Does muscle get bigger by increase in size of individual cells or increase in number? Somewhere in the back of my mind, I have the claim that a muscle never increases its amount of cells but, if the muscle gets bigger, it's simply because individual cells get bigger.
The book Anatomy Trains on page 36 cites "Changes in sarcomere length and physiological properties in immobilized muscle by Williams et al" when it makes the claim :
Stretched, a muscle will attempt to recoil back to its
resting length before giving up and adding more cells
and sarcomeres to bridge the gap.
Is that true? Do muscles increase the number of their cells in that way? The "back of your mind" is correct: "if the muscle gets bigger, it's simply because individual cells get bigger."
Growth of muscle can occur in three ways:
by an increase in muscle cell numbers
by an increase in muscle fiber diameter
by an increase in fiber length.
However, growth in cell numbers is limited to the prenatal and immediately postnatal period, with the animals and man being born with or soon reaching their full complement of muscle cells.
[G]rowth occurs by either hypertrophy of the existing muscle fibers by adding additional myofibrils to increase the muscle mass or by adding new sarcomeres to the ends of the existing muscle fibers to increase their length. Both of these mechanisms occur during the growth process. Growth in the girth of the muscle fibers... may be stimulated by development of stress creating an unequal pressure with splitting at the Z-band and development of additional SR and T-tubule systems. This adds to the diameter or girth of myofibers without any hyperplasia. The growth in length occurs at either end of the fibers and results in addition of new sarcomeres. In both cases, new myofibrillar protein must be synthesized and deposited in the muscle cells.
The following is multiple choice question (with options) to answer.
What will increase as the animal eats more food? | [
"starvation",
"trees",
"belly size",
"hunger"
] | C | as the amount of food an animal eats increases , the weight of that animal will increase |
OpenBookQA | OpenBookQA-2559 | stereo, ros-kinetic
(don't have space to post full code).
Comment by glagla on 2016-08-03:
Could you send me the code you tried by mail? @ svendxs@gmail.com please?
The following is multiple choice question (with options) to answer.
A stereo can run on converted energy through | [
"wires",
"coins",
"AAAs",
"hope"
] | C | batteries convert chemical energy to electrical energy |
OpenBookQA | OpenBookQA-2560 | 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 the most accurate statement? | [
"finches with fat beaks can eat ants in a small anthill",
"finches with narrow beaks can eat only human meat",
"finches with narrow beaks can eat ants in a small anthill",
"finches with fat beaks can eat only human meat"
] | C | a skinny beak is used for obtaining food by a bird from small spaces |
OpenBookQA | OpenBookQA-2561 | homework-and-exercises, newtonian-mechanics, forces, work, free-body-diagram
Title: Problems with work on an inclined plane
A constant force $F_a$ of magnitude $82.0N$ is applied to a $3.00 kg$ shoe box at angle $53.0^{\circ}$, causing the box to move up a frictionless ramp at constant speed. How much work is done on the box by $F$ when the box has moved a through vertical distance $h = 0.150 m$?
The following is multiple choice question (with options) to answer.
Eric is pushing a box up a ramp. He notices that it is much more difficult than it was a couple of hours earlier. This could be due to | [
"The box is a lot lighter than it was earlier",
"the box being grey",
"his box being more voluminous",
"the ramp is more high angle then it was earlier"
] | D | an inclined plane is used for raising objects |
OpenBookQA | OpenBookQA-2562 | physical-chemistry, reaction-mechanism, enthalpy, free-energy
I would think that in order to be able to go to the intermediate state, one needs to provide energy, thus that it could not be spontaneous for this reason. One needs to provide energy, for example by heating, that is increasing temperature.
How is that possible? Any comment? "Spontaneous" means different things in different contexts
Your penultimate paragraph captures a key idea. The explanation for why this is right requires a recognition of the context of the term "spontaneous".
The context of the statement at the start of the question $\Delta G=\Delta H-T\Delta S$ is negative is thermodynamic stability. But this is somewhat at variance with the more natural use of the term which implies "things happen without being pushed". This idea is closer to the idea of kinetic stability in chemistry.
You correctly identify the need to add energy to get the reaction past the transition state. Even if the reaction overall releases energy (thermodynamically spontaneous) the reaction won't just happen if there is a huge barrier to getting over the transition state. There are big kinetic barriers that stop the reaction "just happening". Oxygen and gasoline will react to release energy but this doesn't happen without the push given by the spark plug in the engine of a car.
That barrier is so low in some cases a compound will react with nearly everything with little excuse (chlorine trifluoride will set fire to asbestos). That is a spontaneous reaction in any context. Luckily, few thermodynamically spontaneous reactions are also kinetically spontaneous or humans would catch fire in air.
So when you see the term "spontaneous" ask what is the context: thermodynamic or kinetic? And don't confuse them.
The following is multiple choice question (with options) to answer.
Gasoline is unable to exist without the addition of raw materials such as | [
"air",
"water",
"sand",
"fossilized matter"
] | D | fossils are formed when layers of sediment cover the remains of organisms over time |
OpenBookQA | OpenBookQA-2563 | organic-chemistry, everyday-chemistry, experimental-chemistry, biochemistry, food-chemistry
Title: How Bread is made with yeast, sugar and luke warm milk? Materials and Apparatus:
wheat flour
sugar
dry yeast
glass bowl
covering plate
milk
Procedure:
Lukewarm milk is taken in the glass bowl and sugar is added to it. Then, yeast is added to the same.
The mixture is left undisturbed for 10-12 minutes to activate the yeast
3 cups of wheat flour are added to the bowl containing the milk mixture.
The mixture is mixed thoroughly with 100ml of added water and the dough is kneaded well
The dough is placed in a bowl, covered with a plate and left undisturbed for 2 hours.
My query/confusion:
Why is milk needed?
"activated yeast"- what's the difference?
Can yeast work without sugar or milk.
Detail out the stages of the anaerobic oxidative process which takes place as a common first step in both aerobic and anaerobic respiration.
Finally, feel free to share anything I may be missing which should be here.
If you have any confusion regarding what I want to ask, please ask in the comments. Please upvote if you are curious about it too
milk is not needed, 'pure' bread is without milk
yeast is a fungus, therefore, it is alive. Its best to work with fresh yeast, which you find as small cubes in the refrigerated section. This one does not have to be activated. non-fresh yeast is dried, so in order for it to work properly, it has to be undried by adding water, which is called activation.
and 4. As said before, milk is not needed. Sugar however is the food for the yeast, without it, it does nothing. In aerobic breathing, the yeast metabolizes the sugar as we would: sugar + oxygen -> water + CO2. Without oxygen, the yeast resorts to ethanol fermentation: sugar -> alcohol + CO2 (this is, why it is used to make beer or wine). For making bread, we have a mixture of both respirations, which does not really matter, since we are only interested in the CO2, which makes the dough fluffy =) But without sugar, there is no CO2.
The following is multiple choice question (with options) to answer.
Bread makers only run if you have | [
"an extension cord",
"adamantium claws",
"a power cord",
"dirt and gravel"
] | C | an electrical device requires electricity to turn on |
OpenBookQA | OpenBookQA-2564 | radiation
You see similar things happening here. The metal rod at the top of the lamp acts as a capacitive ground - given the very high voltage, a tiny charge will flow from the tip of the filament to the rod. There is a small amount of gas in the tube which is ionized and gives rise to the light you see. The electrons eventually bombard the metal "anode" and produce Bremsstrahlung - note that without the metal, you were getting a glow and no reading on the Geiger counter. There is a similar demonstration online which is more convincing in its use of conventional materials, but which otherwise shows many of the same phenomena.
It is almost certainly very inefficient. Most of the energy in an X-ray tube is converted to heat as the electrons burrow too deeply into the tungsten target for their radiation to escape- apart from the fact that only the most violent deceleration produces X-rays with high enough energy to penetrate the bulb and be detected.
I noticed that when the "alpha window" was removed, the reading in your video went up. Since there was also a biscuit tin and glass bulb in the way I suspect there was a lot more low energy radiation generated than was detected. Good stuff for skin cancer.
The experiment as shown should not be repeated. Not only were the HV precautions extremely poor, but so were the radiation safety precautions. Please don't try this at home...
The following is multiple choice question (with options) to answer.
Xenons use current to produce light as well as | [
"rainbows",
"thermal exchange",
"darkness",
"heat sinks"
] | B | some light bulbs convert electricity into light and heat energy |
OpenBookQA | OpenBookQA-2565 | 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? | [
"hydrogen is composed of water and oxygen",
"waiters are composed of hydrogen and oxygen",
"most of our oceans, lakes, and pond are composed of hydrogen and oxygen",
"water is composed of hydrojets and oxyclean"
] | C | the composition of something can be used to identify that something |
OpenBookQA | OpenBookQA-2566 | general-biology, habitat
Title: How does life change when you dig deeper? I've just realized that I have no idea what life / biotopes / soil looks like when you dig deeper than a few meters.
I know that in the first meter of soil you can find all sorts of live animals (like moles and rabbits), insects (like ants, but many more), plants, and single-celled organisms, of course.
But how does that change when you get to the depth of a metro station (below 30m)? When you plan to build a metro, do you have to consider that you might destroy a biotope?
I guess there is a point from which you will quite certainly not find animal/plant life in the soil anymore. This will, of course, depend on where exactly you are. But can you give a rough estimate of how deep we're talking? 50m? 100m? 1km? Extremophile bacteria and archea are living very deep beyond our imaginations. This is what you need for general composition at different depths. And this and this is for the deepest living organism known ! Following is image from (Manson et al 2010) which shows at what depth you will get bacteria
Even more deeper, Wold's single species ecosystem, Desulforudis audaxviator which can be found 3 km below sea level.
The following is multiple choice question (with options) to answer.
Moles are underground a lot of the time, and since few animals live there, they are unlikely to be | [
"dirty",
"killed by others",
"in dirt",
"near worms"
] | B | living underground can be used for hiding from predators |
OpenBookQA | OpenBookQA-2567 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
Polar bears are best suited for | [
"colder places",
"hotter regions",
"Jupiter's polar caps",
"northern desert regions"
] | A | living in an environment causes an organism to adapt to that environment |
OpenBookQA | OpenBookQA-2568 | species-identification, ornithology
Title: Help me find out what this bird is (description, no picture) A while ago I read about this bird(s) whose species status was not confirmed. This was because they had a very large distribution and birds in adjacent population could breed with each other but birds at each end of the distribution (western Europe and South Asia I think) couldn't. I am pretty sure that they were some kind of gull and from Europe to Asia their wings got lighter, from black to grey. I think I might have read about them in a Richard Dawkins book.
Does anyone know the species I'm talking about? You're describing a Ring Species: "a connected series of neighbouring populations, each of which can interbreed with closely sited related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population".
The classic ring species is the Herring Gull complex, and that's probably what you read about:
The classical example of the ring species model was originally based upon the herring gull complex (Mayr 1942). This group comprises more than 20 taxa of large gulls (Haffer 1982) which together occupy a circumpolar breeding range in the northern hemisphere. ... Mayr envisioned all taxa of the circumpolar chain to be connected by gene flow, while herring and lesser black-backed gulls in Europe, the hypothetical endpoints of the ring, have reached full reproductive isolation and now coexist as distinct species.
--The Herring Gull Complex (Larus argentatus - fuscus - cachinnans) as a Model Group for Recent Holarctic Vertebrate Radiations
However, recent genetic work shows that the situation is even more complicated than this, and it's questionable whether they really are "ring species":
Contrary to the ring-species model, we find no genetic evidence for a closure of the circumpolar ring through colonization of Europe by North American herring gulls. However, closure of the ring in the opposite direction may be imminent, with lesser black-backed gulls about to colonize North America.
--The herring gull complex is not a ring species.
The following is multiple choice question (with options) to answer.
A bird that finds itself endangered is | [
"sees others of its species in large amounts",
"friendly with many other birds",
"glad to have so much company",
"unlikely to meet more of its type"
] | D | endangered means low in population |
OpenBookQA | OpenBookQA-2569 | Note:
Depending on where, and how frequently, you round during this function, your answers may be off a few cents in either direction. Try rounding as few times as possible in order to increase the accuracy of your result.
The following is multiple choice question (with options) to answer.
Which is most accurate? | [
"the Earth revolves around a large, bright nuclear reactor",
"the sun makes magical reactions that are visible",
"the sun makes nuclear reactions that are visible instantly",
"the sun makes nuclear reactions that are visible only days later"
] | A | nuclear reactions in stars causes stars to produce light |
OpenBookQA | OpenBookQA-2570 | ocean, glaciology, ice, ecology, cryosphere
Title: Do icebergs have any impact on ecology? Are icebergs neutral actors in the environment, or do they have any impact on the local ecology. Do they have any environmental impacts that might influence any part of the biosphere? Yes, they have many impacts:
They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (here is one).
They transport sediments and nutrients into the ocean.
They provide safe rest areas for animals like seals, birds and penguins.
They impact the temperature of surface waters, specially in fjords.
They stir the sea floor in shallow waters
And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.
The following is multiple choice question (with options) to answer.
Which of the following would be the most impactful to an ecosystem? | [
"an 8.1 earthquake",
"a tree falling",
"a light rainfall",
"a minor snowstorm"
] | A | natural events usually cause changes to Earth 's surface |
OpenBookQA | OpenBookQA-2571 | cosmology, string-theory, quantum-gravity, theory-of-everything, poincare-recurrence
The timescale is vastly longer than anything we have a chance to experimentally test. Each 10 billion years or so, the linear distances between galaxies double and the density of normal matter decreases by an order of magnitude. In hundreds of billions of years, a vast majority of the currently active stars will be inactive and even "new generations" of the stars will already be gone or dying. In trillions or certainly quadrillion years, there will be nothing left to energize star-powered life as we know it, and similar "local, more modest" sources of useful energy will be diminishing in similar ways.
It is hard to imagine that there will be any intelligent beings in a quadrillion years. This is still vastly smaller than the Poincaré recurrence time. And this result of the comparison is no coincidence. Of course that things must have a chance to "destroy any pattern" before the chaos has a chance to reassemble itself into the patterns again.
The following is multiple choice question (with options) to answer.
If our globe is split in half, the innards would be | [
"stony",
"ice",
"hollow",
"gold"
] | A | Earth 's surface is made of rock |
OpenBookQA | OpenBookQA-2572 | forces, air, coriolis-effect
Title: Does Coriolis effect affect snowing? Right now, outside is snowing. No matter what window I look from, the snow constantly for last few hours tends to fall to the right close to the window, and to the left close to the building across the street, just like it would suggest the Coriolis effect on northern hemisphere.
I understand the Coriolis effect applies for air flow and the reasons for this may be in something completely different, specific to the street I am in. But in theory - could the Coriolis effect on snowing be so dramatic, it would be observable?
could the Coriolis effect on snowing be so dramatic...?
No. The Coriolis effect is only noticeable for objects traveling long distances with respect to Earth's surface for significant periods of time. For example, a ballistic missile fired hundreds of miles or a hurricaine that is hundreds of miles in diameter and lasts for days. Across the street is too small a distance for an noticeable effect.
The Rossby Number can be used to determine if the Coriolis effect is significant in a given situation.
Another way of thinking of it is: the Earth only rotates once a day, how does the phenomenon being investigated compare to this fact?
The following is multiple choice question (with options) to answer.
Geese fly south for the winter because | [
"they miss relatives",
"of a vacation",
"their following orders",
"of instinct"
] | D | migration is an instinctive behavior |
OpenBookQA | OpenBookQA-2573 | meteorology, atmosphere, geophysics, climate, geography
Finally, I have to note that I've interpreted "calmest" as the minimum mean wind speed. However, it would be sensible also to consider it as the place with the lowest maximum wind speed or some other metric, that would perhaps change the picture described above. And maybe using that metric one of the Antarctic domes could be the "calmest" place. But I won't extend the answer further with any possible interpretation for "calmest".
The following is multiple choice question (with options) to answer.
Where would one likely find the least water? | [
"in the elephant's habitat",
"in the crab's habitat",
"in the cow's habitat",
"in the cactus' habitat"
] | D | as dryness increases in an environment , the available water in that environment will decrease |
OpenBookQA | OpenBookQA-2574 | fluid-statics
Title: Is this watering with gravity concept possible with physics?
I was thinking of putting together a auto watering scheme for my plants. Main objective is to just have one place to fill water, and it will disperse to several cups equally. I might have the physics wrong but i remember some force which creates suction with gravity and keeps the containers equally filled. I tried to draw the idea, and i'm wondering if anyone have any feedback on if this is possible?
The idea here is that the gravity will bring the water from the top container which stands taller, and then fills the small containers with water. The sketch is of a high reservoir, with multiple level-controlled smaller tanks.
So, it implies that the (lower level) tanks are equipped with a valve that
shuts off the water when a target level is reached: it's just like the
shutoff mechanism in the tank of a toilet. There's a float, which operates
the valve. It doesnt equalize gallons per day, though, just level-in-a-tank.
So, you can definitely find items at a hardware store to build such a system.
If, on the other hand, you want to partition a water source to multiple
destinations based on delivered water volume being equal, the usual
approach is to use a timed valve to a pressurized manifold, and use
matched emitters (i.e. drip irrigation controlled-flow drip fittings).
The physical principle of these emitters is the Bernoulli effect, they
are fabricated so that too-fast water flow in the valve pulls the
aperture shut (this sounds hard, but it isn't). Over a range
of water pressure, the drip rate stays nearly constant. They usually
require pump pressure (or water-utility pressure) though, would clog
if you just used a few feet of gravity-driven flow.
The following is multiple choice question (with options) to answer.
When a plant is water the liquid goes from the soil area to where it is needed using what system? | [
"xylem",
"flowering pistols",
"sprinkler",
"leaves"
] | A | xylem carries water from the roots of a plant to the leaves of a plant |
OpenBookQA | OpenBookQA-2575 | phylogenetics, trees, visualization
An interesting - and new to me - point of view is given in Joseph Ahrens' answer to this Quora question:
How do you interpret ancestry in phylogenetic trees?
What slowly becomes clear to me: It's about the interpretation of straight line segments, maximal straight lines, of horizontal vs. vertical lines, and nodes (= branching points) in phylogenetic trees, especially: which of them is to interpreted as a species? Here's the issues with your well considered project:
1/ Temporal datasets to proportion trees: That's probably the most absent thing in species measurement. You'd need data sets of time for beetle species, for mammals, plants in millenia and million years. 90+% of that information is absent.
2/ Genetic proximity to arrange trees. Scientists publish their genome studies into the ToL project. There is lots of distance data to compare all animals.... Genetic distance doesn't graph easily because on the same tree, some distances can be 500 times longer than others. On a tree of 20 extant species, you will have branches 5mm long and 5 meters long, half the the species are on your screen and the other half are higher than the ceiling. It's best to represent them with another symbol, else interactive 3D trees where you can switch compact/large views and the tree zooms out crazily, it's illustrative and cool, else use a weighted proximity length which is 1+ similarity/50, that doesn't really work either. either way, I couldnt find a way of clearly displaying that info on the tree.
Phylogeny trees don't lend themselves well to being informatively measured. You start by thinking "Oh I could find a pretty way of doing that" then when you apply the datasets, your trees become uncontrollable and jumbled up because of exponential branch lengths.
I programmed phylogenetic trees based on the 81MB ToL tree of life project to represent many millions of species, to do 3D physics trees and HTTP lookups to provide wiki texts and images for all species. There is www.biostars.org a very kind and helpful bioinformatics forum for postgrads that do trees all day.
There are many (dozens) of informative tree graphics programs coded by academics, to visualizw and analyzw species data, arranged into different trees and sorting through them.
The following is multiple choice question (with options) to answer.
While studying the rings in a fossilized tree trunk, a scientist notices a group of rings that are closer together than the other. This means that | [
"the trees had more sunlight for those years",
"the trees were dead during those years",
"during those years, there was less precipitation",
"the trees had extra water those years"
] | C | as the amount of available water decreases , tree-growth rings will become narrower |
OpenBookQA | OpenBookQA-2576 | c++, console, simulation
bool keepWinOpen = true;
while (keepWinOpen) {
// 'q' to quit
int in = getch();
if (in == 'q') {
keepWinOpen = false;
}
/*------------------------------------------------------------------------------
DumbBug Behavior
------------------------------------------------------------------------------*/
for (int i = 0; i < dumbBugs.size(); i++)
{
DumbBug* b = &dumbBugs[i];
b->energy--;
b->surroundings = t.findDirectSurroundings(b->currentPos);
switch(b->act())
{
case die:
{
t.killLife(dumbBugs, i);
} break;
case layegg:
{
int r = rand() % directions.size();
if (canSupportBug(t, b->currentPos + directions[(Direction)r]))
dumbBugEggs.push_back(t.newLife(DumbBugEgg(b->currentPos + directions[(Direction)r])));
b->energy = 100;
} break;
case eat:
{
for (int j = 0; j < b->surroundings.size(); j++) {
if (b->surroundings[(Direction)j] == SMALLPLANT_SYM) {
t.changeCharAt(b->currentPos + directions[(Direction)j], EMPTY_SYM);
j = b->surroundings.size();
}
}
b->energy += 20;
} break;
The following is multiple choice question (with options) to answer.
crops need to be switched on a continual basis why? | [
"the animal habitats",
"for more pests",
"bees and birds",
"more wanted vitamins"
] | D | farming cause nutrients in the soil to decrease |
OpenBookQA | OpenBookQA-2577 | Good question. I especially liked your journey (seen through your edits) as you were grappling with this problem. I wish more questions on this site were written like this.
The very short answer is: Yes, we need to disambiguate the word "accuracy" and we also need the prior probability.
What does prediction accuracy mean?
You are right to wonder. This is not a well-defined term. When we are making predictions about a binary event (for example: cat dead or alive, or as another example: a person either has the disease or not) and we want to measure how good a prediction method is, we should use two numbers: The rate of true positives and the rate of true negatives. These are usually called sensitivity and specificity respectively. Using your notation and considering the prediction of witch $A$, these are the quantities: $P(A_L|L)$ and $P(A_D|D)$. So sensitivity (true positive rate) is the probability that witch $A$ predicts the cat alive, given that the cat is alive (or will be alive). Specificity (true negative rate) is the probability that witch $A$ predicts the cat dead, given that the cat is (or will be) dead.
You have already identified these quantities are important, and you are wondering how accuracy relates to them. The most straightforward interpretation is your first one, namely that both sensitivity and specificity are equal to the number given as "accuracy". You can view this interpretation as the prediction method being equally "accurate" both for the positive events (cat alive) and negative events (cat dead). Even though this is probably the most straightforward interpretation, the problem description should be explicit about what it means by the single quantity "accuracy".
So the takeaway message is: prediction quality is defined by two numbers (which often people presume equal and give you just one number).
The following is multiple choice question (with options) to answer.
Which is more accurate: | [
"sharks use gills to swim underwater for longer than humans can",
"humans use gills to extract carbon from the water",
"sharks use gills to extract carbon from the water",
"sharks are unable to find oxygen while underwater"
] | A | gills are used for breathing water by aquatic animals |
OpenBookQA | OpenBookQA-2578 | newtonian-mechanics, everyday-life, collision, spring
But if you pull the small block away from the large block slowly, then the large block will follow the small block, while the spring doesn't stretch terribly much. In this case, the low acceleration of the large mass takes place over a longer time, and so it can move more while the force is being exerted on it. This is the equivalent of going over a bump/pothole at low speed; since the wheels move up or down relatively slowly, the frame of the car will follow them. If you go over a bump at low speed, this means that the frame will follow the wheels (which follow the road surface), rather than moving in something resembling a straight line and possibly hitting the road surface.
The following is multiple choice question (with options) to answer.
As the car approaches a hill it will become harder to | [
"steer",
"park",
"push",
"brake"
] | C | as the resistance to something increases , how easilty that something can be done will decrease |
OpenBookQA | OpenBookQA-2579 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
Which animal might catch it's sustenance faster? | [
"Snail",
"Frigate Bird",
"turtle",
"Sloth"
] | B | if an organism 's prey moves quickly then that organism may need to move quickly to catch its prey |
OpenBookQA | OpenBookQA-2580 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
If a tiny bug needs to be closely observed, a person could enlist the use of a | [
"glass slipper",
"crock pot",
"ceramic plate",
"enlarger"
] | D | magnifying glass is used to see small things by making objects appear bigger |
OpenBookQA | OpenBookQA-2581 | newtonian-mechanics, newtonian-gravity, acceleration, collision, free-fall
Title: What would happen if when falling down you get pushed up? I know it will be a weird question, but im not a physics well informed person and I had this unsolved question for long time.
What would happen if lets say you are falling with someone else from 10meters and in the last meter that other person pushes you up?, would you lose the falling speed or decrease it enough to survive the fall damage? It depends on how hard you can push. Realistically, it would not have much effect. After all, the height at which you can throw a person is negligible compared to $10$ meters. Btw, at such heights, you can use the free fall equation and get the impact velocity of roughly $35$ km/h, so it is survivable as expected. My guess is that if the other person is trying to preserve you, his best strategy would be to hug you to cushion your fall. He can't change the impact velocity, but by lengthening the deceleration phase (which the most vital part) it might be worth it at his expense. Hope this helps.
The following is multiple choice question (with options) to answer.
If this fell on you, you would probably die | [
"a leaning tower",
"a balloon",
"a feather",
"a towel"
] | A | buildings collapsing often cause death |
OpenBookQA | OpenBookQA-2582 | human-biology, toxicology
Title: Is nicotine toxic to humans? More specifically, is nicotine in the concentrations that smokers receive when smoking cigarettes toxic? I know that in great enough concentrations it can be toxic (but then, so can just about anything else, including oxygen) and I know that in plants it is used as a defense against insects and can even be used as an insecticide. However, it has always been my understanding that nicotine is irrelevant as far as the harmful effects of smoking go.
I recently had a conversation with another biologist who had just quit smoking and had done quite a bit of research on the subject. He said that nicotine itself is in fact bad for you and, therefore, that tobacco-less alternatives to cigarettes (such as electronic cigarettes) are still harmful because of the nicotine alone.
Does anyone have any more information on this? Perhaps some references? Or, even better, a detailed explanation of the pathways involved? Again, I stress, not about nicotine's toxicity in general but about its harmful effects on vertebrates (preferably human) at the kinds of concentrations one could expect to ingest when smoking. I think its useful to say that nicotine is not very toxic to humans - cells don't die or get sick for typical smoking habits. Secondary health effects are possible, but here is a toxicological profiles.
Nicotine is a toxin in large enough quantities and nicotine has an LD50 (lethal dose for 50% of individuals) of 0.5-1 mg Nicotine / kg of body weight. So even a small spill on your skin of the chemical can be life threatening, but for smokers the nicotine itself is not dangerous.
Individuals who smoke intake about 1 mg per cigarette smoked. So a small adult (110 lbs) can smoke 25 cigarettes in a short period of time (or all at once!) and just barely get to the bottom end of that limit. Nicotine is water soluble and clears out through the urine at a fast rate though - half of the nicotine from a cigarette is cleared from your system within 2 hours, which means that 4-5 pack a day smokers are not really killing themselves (from nicotine).
That being said, children are about 5-10 times more sensitive than adults, so even 5-6 cigarettes in an hour can be toxic. That's quite a bit of smoking though.
The following is multiple choice question (with options) to answer.
If a puppy steps on a lit cigarette, it is likely | [
"happy",
"swell",
"lovely",
"pained"
] | D | burning a living thing usually causes harm to that living thing |
OpenBookQA | OpenBookQA-2583 | seismology, earthquakes, seismic-hazards, drilling
Title: Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes? The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (link)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (link)--let's assume it is 100 km.
That said, if a seismic station is installed at a depth of 50 km, and there are many of them in any given metropolitan area, then we can have a warning that is tens of seconds before the earthquake reaches the surface.
While I realize that drilling down to 50 kn is no easy task, I would have imagined that saving human life is well worth the efforts. Why hasn't this been done so far? Is it that such a short notice (10s of seconds) isn't worth it? The simple answer is that you can't drill to 50 km depth.
The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific drilling project. The very few others were oil exploration boreholes.
Drilling that deep is extremely expensive and hard. If you go and ask anyone who ever worked on a drill rig, drilling the second 100 metres is always harder than the first 100 metres. And we're talking about kilometres here! There are several problems with drilling that deep. It's extremely hot down there, and the drilling equipment just breaks and stops working. You also need to pump cooling water in and pump out the stuff you're drilling and it gets harder with depth.
This is simply not feasible. Now let's say that you did somehow manage to drill a hole to that depth. How would you put monitoring equipment inside? That equipment has to sustain heat and pressure and still keep working, while being able to transmit whatever it's reading back to the surface. This is not going to happen, not at 50 or 10 km depth.
Another problem is that not all earthquakes are that deep. Some earthquakes originate near the surface, or just several km deep. Having a monitoring station down there isn't going to help. The 2011 Tohoku earthquake (the one that triggered the tsunami at Fukushima) was only 30 km deep. Same thing for the 2004 Indian Ocean earthquake.
The following is multiple choice question (with options) to answer.
What might happen in an Earthquake? | [
"It is the start of the Olympics",
"Cats come out of the crack",
"Jimmy may need to move",
"A magical god comes out"
] | C | an earthquake changes Earth 's surface quickly |
OpenBookQA | OpenBookQA-2584 | photosynthesis
Title: What vegetation would thrive in the Martian atmosphere? Most plants require carbon dioxide for their photosynthesis, which Mars has in overabundance.
Would atmosphere composition (let's ignore temperatures for the purpose of this question) of Mars allow vegetation to grow? This is not my field by a long shot, so take what I say with a grain of salt. However, this question is very hard to answer because whether or not a plant will grow depends on a great variety of factors. Even if we ignore the temperature as you say, there are other considerations. These include, but are not limited to:
Soil composition, I doubt that Martian soil can support earth vegetation even if its atmosphere could. Plants need various nutrients, and specific pH ranges among other things.
Atmospheric pressure, I am not at all sure that the Martian atmosphere (though it is, indeed rich in CO2) would be enough to drive an earth plant's photosynthesis. Bear in mind that the atmospheric pressure on Mars averages 600 pascals (0.087 psi), about 0.6% of Earth's mean sea level pressure (source). This makes it highly unlikely that unmodified earth plants would be able to thrive there.
Water water water...
Pollinating species. Many many plants depend on other species (e.g. bees or hummingbirds) for their propagation. These would be hard to find on Mars.
Sunlight I don't know if Mars receives enough sunlight at its distance from the sun to drive an unmodified plant's photosynthesis.
Now, that said, it should theoretically be possible to start with some extremophile archaea or bacteria that would over the course of many many many years (at least hundreds, thousands more probably) terraform Mars to make it suitable for human habitation. Specially engineered plants could play a role then but I find it very hard to believe that any existing, unmodified, multicellular plant life of earth origin could survive on Mars.
The following is multiple choice question (with options) to answer.
A blackberry bush needing to photosynthesize would have difficulty | [
"under the sun",
"at night",
"in summer weather",
"in daylight"
] | B | darkness has a negative impact on photosynthesis |
OpenBookQA | OpenBookQA-2585 | reproduction, human-genetics, human-genome
I missed the "as a species" part of your question. Inbreeding will only likely have an effect within small, closed populations, though it will continue to have a lasting effect even as those populations grow and open up. Two textbook examples are French Canadians and Ashkenazi Jews. Even now, there is continued elevated risk of certain rare genetic diseases in these populations. As for the species as a whole, it is likely to be really detrimental only if the effective population size of the species becomes really low: a general rule of thumb used by conservation biologists is that the effective population size should be at least 50 to avoid the effects of inbreeding (and 500 to avoid the effects of genetic drift) (50/500 rule).
Sorry about the confusion.
The following is multiple choice question (with options) to answer.
The population of zebras is stagnant due to a lack of new baby zebras, what will happen over time to the community without support? | [
"sadness",
"resurgence",
"shrinkage",
"regrowth"
] | C | if an organism dies then the population of that organism will decrease |
OpenBookQA | OpenBookQA-2586 | virus, life, philosophy-of-science
Title: Is there any definition of life which makes viruses undeterminable? There are many different definitions of life (RNA, something that comes through evolution) but not one I have seen which could not determine wheter viruses are living things (even though there are many definitions both for YES and NO). Are there any such definitions (I'm looking for cases where it's really fundamental debate, not only struggling for the correct dictionary definition)?
Thank you. Your last sentence is the key: defining life really is just finding a dictionary definition that we can agree upon. Biology is something that defies discrete definitions at times: "What is it to be alive?" "What is a species?" maybe even "What is the wild type allele of a gene?"
I would recommend not looking at viruses as a challenge to determine if they are alive or not so much as an excellent opportunity to discuss what we think are important characteristics of life.
Life can alternately be described as:
"Comprised of self-replicating cells" (a paraphrase of the "Cell Theory of Life"
or
As things that embody at least most of the following characteristics:
1. Self-Replicating
2. Metabolizing
3. Growing
4. Showing signs of adaptation
5. Being organized
6. Respond to their environment
7. Being comprised of cells
I like to think that we should focus on extraterrestrial forms when we define life. i.e. what would we want to see in an extraterrestrial in order to call it 'life'? While some are troubled by calling viruses alive here on earth, the same people might be willing to say that we have found extraterrestrial life on another planet if it was similar (granted, it's hard to imagine this kind of life existing without a host...)
as an aside: You might also ask whether this question is fit for this stack as it can not be supported by literature references (at least none that would actually support a conclusion). So should this be posted as 'Biology' or 'Philosophy'?
The following is multiple choice question (with options) to answer.
Which of these describes a living thing? | [
"one thing doing nothing",
"large body of inanimate material",
"many small things working together",
"large lake of moving water"
] | C | a living thing is made of cells |
OpenBookQA | OpenBookQA-2587 | evolution, vision, neurophysiology
Mid-reds with mid-greens
Blue-greens with grey and mid-pinks
Bright greens with yellows
Pale pinks with light grey
Mid-reds with mid-brown
Light blues with lilac
There are reports on the benefits of being red-green color blind under certain specific conditions. For example, Morgan et al. (1992) report that the identification of a target area with a different texture or orientation pattern was performed better by dichromats when the surfaces were painted with irrelevant colors. In other words, when color is simply a distractor and confuses the subject to focus on the task (i.e., texture or orientation discrimination), the lack of red-green color vision can actually be beneficial. This in turn could be interpreted as dichromatic vision being beneficial over trichromatic vision to detect color-camouflaged objects.
Reports on improved foraging of dichromats under low-lighting are debated, but cannot be excluded. The better camouflage-breaking performance of dichromats is, however, an established phenomenon (Cain et al., 2010).
During the Second World War it was suggested that color-deficient observers could often penetrate camouflage that deceived the normal observer. The idea has been a recurrent one, both with respect to military camouflage and with respect to the camouflage of the natural world (reviewed in Morgan et al. (1992)
Outlines, rather than colors, are responsible for pattern recognition. In the military, colorblind snipers and spotters are highly valued for these reasons (source: De Paul University). If you sit back far from your screen, look at the normal full-color picture on the left and compare it to the dichromatic picture on the right; the picture on the right appears at higher contrast in trichromats, but dichromats may not see any difference between the two:
Left: full-color image, right: dichromatic image. source: De Paul University
However, I think the dichromat trait is simply not selected against strongly and this would explain its existence more easily than finding reasons it would be selected for (Morgan et al., 1992).
References
- Cain et al., Biol Lett (2010); 6, 3–38
- Morgan et al., Proc R Soc B (1992); 248: 291-5
The following is multiple choice question (with options) to answer.
An example of camouflage could be | [
"Baking a cake for a birthday",
"A sting ray covering itself in sand",
"Cleaning make up off my face",
"Going naked outside on a rainy day"
] | B | An example of camouflage is an organism looking like leaves |
OpenBookQA | OpenBookQA-2588 | friction
as expected.
So the blocks will slide over one another if
$\dfrac {F_1M + F_2m}{M+m} > Fr_{max} = \mu mg$
If $F_2 > F_1$ then a similar calculation gives the same condition.
The following is multiple choice question (with options) to answer.
Sliding off concrete and onto gravel produces higher levels of | [
"shine",
"value",
"longevity",
"chafing"
] | D | as roughness of a surface increases , friction will increase |
OpenBookQA | OpenBookQA-2589 | electricity, electric-circuits, electric-current, earth
Title: Will I get a shock when I try to use my hair-dryer under water? Occasionally people get killed in their bathtubs by having an electrical device such as a hair-dryer take the bath with them - in movies.
It seems to be a common belief that this is realistic, even though it makes no sense to me.
There are two scenarios:
The device short-circuits internally (that means entirely over either both poles of the energy supply having contact with water, or the pole under electric tension together with the earth conductor - that way, the current should not leave the devices chassis).
The device short-circuits over the pole under electric tension and the bathtub itself (earth eventually, but a different route).
In the first case (which I thought would be common, since the earth conductor is often connected to prominent large metal parts for safety reasons) I can't see what should happen: Clearly a human being wouldn't be affected from that local a current that takes place entirely in the chassis of the device - or am I mistaken?
In the second case, the question is whether the human body is more conductive (including the skin barrier) than the bathtub water. And even if it was, which I don't know, that would only make a difference if this circumstance would actually lead to a shortcut the current could take on its way to earth.
All that sounds like a lot of "ifs" to me, so I thought I put the question out here.
What do people think on the physics?
Do people have links to statistics, that is: does this at all happen?
The device short-circuits internally (that means entirely over either both poles of the energy supply having contact with water, or the pole under electric tension together with the earth conductor - that way, the current should not leave the devices chassis).
Think what the short will do: it will melt the hair drier parts and the live side of the incoming circuit will connect with the water and the water through the taps and supports of the tub to the ground. You will be holding something sparking and in contact with the water, all wet. So unless the fuse goes off there is great danger the sparks will include you too because they will be erratic. i.e. your second scenario
The device short-circuits over the pole under electric tension and the bathtub itself (earth eventually, but a different route).
The following is multiple choice question (with options) to answer.
Which would result in the worst consequences if placed in a full bathtub? | [
"a wooden duck",
"a powered toaster",
"a toy boat",
"an unpowered toaster"
] | B | water is an electrical conductor |
OpenBookQA | OpenBookQA-2590 | zoology, marsupials
Title: Do male marsupials have a pouch? Do male marsupials have a pouch, or is it a female organ only (like the womb)? In most marsupials, only the females have a pouch. However, males of the water opossum and the extinct tasmanian tiger (or thylacine) also have a pouch. The males of both the thylacine and water opposum used/use their pouch to keep their genitalia from getting entangled in vegetation.
The following is multiple choice question (with options) to answer.
When the Platypus emerges into the pouch it has been | [
"ran",
"died",
"birthed",
"flown"
] | C | mammals give birth to live young |
OpenBookQA | OpenBookQA-2591 | thermodynamics, everyday-life
Title: Why do fruits left to dry in the sun feel so much warmer to the touch than other objects outside? I have been putting preserved plums, on a rack, to sun and dry on my balcony. When I take them in at dusk, the plums are noticeably hot to the touch. They feel warmer than the bamboo and metal racks they are on, the cardboard box I put the racks on, the netting I put over the lot, and the air outside. (Note that ambient air temperature doesn't start dropping until well after I have the plums indoors.) The balcony itself, made out of a light-colored concrete-like composite, and the metal railing also feel warm, but not as much as the plums do.
I recall some relevant concepts from physics classes, but I can't tell if I'm taking into account everything at play. Here's what I have so far:
Plums are mostly water, which has a high specific heat (~4 kJ/kg/K) relative to air (~1 kJ/kg/K) and probably the other objects. I'm guessing the balcony also has a higher specific heat than air. Higher specific heat means that by the end of the day, the plums have stored more thermal energy than the cardboard box.
Water and metal are good thermal conductors, so they will feel warmer to my hands than the other objects even if they contain the same energy per unit.
Is there something else in here about the plums converting radiant energy to thermal that the other objects don't, or something about air flow? Is it a sign (which I suppose is not for Physics.SE) of fermentation? You were on track...and then missed the mark.
Higher specific heat means that by the end of the day, the plums have stored more thermal energy than the cardboard box."
Correct. You're on track...
Water and metal are good thermal conductors, so they will feel warmer to my hands than the other objects even if they contain the same energy per unit.
The following is multiple choice question (with options) to answer.
Which feels hotter? | [
"90 degrees Fahrenheit, high humidity",
"low temperature, low humidity",
"low temperature, high humidity",
"90 degrees Fahrenheit, low humidity"
] | A | humidity is the amount of water vapor in the air |
OpenBookQA | OpenBookQA-2592 | the-moon, earth, tidal-locking
Title: Earth rising and setting from moon's perspective Why the earth is rising and setting seen from the moon,
when the moon is tidally locked?
Shouldn't the earth be always on the same spot because of the tidal lock, if observed from the moon? You're quite right. The Earth is (nearly) stationary in the Moon's sky.
(I say "nearly" because the Moon is in a slightly elliptical orbit around the Earth, but rotates perfectly smoothly. This means that the Earth's motion through the Lunar sky is
a bit faster when the Moon is at perigee and a bit slower when it's at apogee. Because the Moon is tide-locked, on average they match perfectly, but during the course of the sidereal month the Earth appears to move back and forth by a few degrees. The effect isn't huge, but it's easily observable with a telescope. See the Wikipedia article on
"libration" for an OK discussion and a really great animated gif illustration of libration as viewed from Earth.)
Is it possible that you're reacting to the amazing movie from Apollo 8 showing Earthrise over the Lunar horizon? It's been int he news a lot given that this is the 50th anniversary of the flight. If so, what you saw there was not from the Moon's surface, but from orbit around the Moon and the Earthrise happened as Apollo 8 came around from behind the moon (where the Earth is not visible in the sky) and the Earth first became visible around the edge of the Moon.
The following is multiple choice question (with options) to answer.
When the moon, sun, and earth line up, tides are at their | [
"Happy",
"Max",
"Min",
"Middle"
] | B | the gravitational pull of the Moon on Earth 's oceans causes the tides |
OpenBookQA | OpenBookQA-2593 | python, object-oriented, design-patterns, flask, strategy-pattern
Title: on using the strategy pattern to switch between database layers I'd like to build an app in Flask that can switch between talking to a PostGresql and a Mongo DB. As I understand it, the Strategy Pattern is about being able to switch algorithms that are referred to by some method call on the fly. So, I think this pattern would be relevant because I want to switch out what abstract functions like create, read, update, delete do. It sounds to me like strategy would be relevant here, but I'm not quite sure how to implement it. Here's what I'm thinking:
I have this file to handle my routes:
from flask import Blueprint
from .models import Entity
api = Blueprint('api', __name__, url_prefix='/api')
from .models.EntityWrapper import Entity
@api.route('/entities', methods=['POST'])
def create_entity():
entity = EntityWrapper(label="cheese")
entity.save()
return jsonify(entity)
@api.route('/entities')
def get_entities():
entities = Entity.read()
return jsonify(entities)
The save and read methods should do different things, depending on which database is being used. The class they belong to, EntityWrapper, reads the environment variables and selects which kind of Entity class should be exported:
import os
from .Entity_mongo import Entity as MongoEntity
from .Entity_postgres import Entity as PostgresEntity
from dotenv import load_dotenv, find_dotenv
load_dotenv(find_dotenv())
DB_TYPE = os.environ.get("DB_TYPE")
Entity = None
if DB_TYPE == 'mongo':
Entity = MongoEntity
elif DB_TYPE == 'postgres':
Entity = PostgresEntity
else:
raise Exception("'DB_TYPE' improperly defined in .env")
Here's Entity_posgres.py
from .Model_postgres import PostgresModel
The following is multiple choice question (with options) to answer.
What pattern best describes most migration? | [
"west to east",
"north to south",
"east to west",
"south to north"
] | B | migration is when animals move to different locations in an annual cycle |
OpenBookQA | OpenBookQA-2594 | phase-transition, biophysics, medical-physics, glass, amorphous-solids
313 6003 pp573-5 (1985).
This outcome was identified as early as the 1960s by electron microscopy of thawed cells, which revealed many puncture holes in the membrane.
Both freezing and rethawing are opportunities for damage, as recrystallization can occur during the latter regardless of how carefully the former was performed.
Freezing into the crystalline phase of ice (and many other materials) produces sharp dendrites because some crystal orientations exhibit very fast growth kinetics. This issue doesn't arise with amorphous freezing.
For an early discussion, see, for example, Mazur's "Cryobiology: the freezing of biological systems" Science 168 3934
pp939-49 (1970) and the references within.
The following is multiple choice question (with options) to answer.
Ice wedging might create | [
"buildings",
"Beds",
"cars",
"mountainsides"
] | D | ice wedging is when ice causes rocks to crack by expanding in openings |
OpenBookQA | OpenBookQA-2595 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
some countries can be in bed and other are in the middle of the day enjoying the outdoors, why? | [
"animals",
"rotation of sun",
"planet rotation",
"ocean tides"
] | C | if it is night then the sun has set |
OpenBookQA | OpenBookQA-2596 | 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.
In order for trees to use sunlight they must | [
"their roots",
"the light switch",
"CPR",
"respire"
] | D | living things require respiration to use energy |
OpenBookQA | OpenBookQA-2597 | 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.
A car hitting a rolling boulder can cause the car to | [
"increase in value",
"wet itself",
"play the radio",
"decrease momentum"
] | D | a force acting on an object in the opposite direction that the object is moving can cause that object 's speed to decrease in a forward motion |
OpenBookQA | OpenBookQA-2598 | neuroscience, perception, senses
Fig. 1. The BrainPort converts camera images into a 'grayscale' 400 pixel electrotactile image on the tongue. It partially restores visual function in the blind. Picture source: Midday Daily
The following is multiple choice question (with options) to answer.
If I was blind I could use my hands to tell what | [
"the color of Susie's eyes",
"the color of the sky",
"the color of Bob's hair",
"the shape of Tom's nose"
] | D | the shape of an object can be discovered through feeling that object |
OpenBookQA | OpenBookQA-2599 | A. 144
B. 122.5
C. 105.10
D. 72
E. 134
Another weighted average approach, expressed a bit differently.
Track on milk. We know the desired concentration of milk in the resultant mixture.
Milk is a fraction (or percentage or concentration) of all three mixtures of milk and water. The weighted average formula accounts for water by way of volume.
This formula is easy (concentration can be a percentage or a fraction):
$$(Concentration_{A})(Vol_{A}) + (Concentration_{B})(Vol_{B})$$
$$=(Concentration_{A+B})(Vol_{A+B})$$
Let A = # of gallons of A (volume)
1) Use ratios and desired percentage to find the concentration of milk in A, B, and end mixture
(With ratios, remember to find $$\frac{part}{whole}$$)
In mixture A, $$\frac{Milk}{Water}=\frac{2}{5}$$
2 parts milk, 5 parts water, total parts = 7
So in A, milk is $$\frac{2parts}{7parts}=\frac{2}{7}$$
In the second mixture, B, milk is what fraction?
$$\frac{M}{W}=\frac{5}{4}$$
B, concentration of milk $$=\frac{5}{4+5}=\frac{5}{9}$$
Resultant mixture, desired concentration =
40% milk $$=\frac{40}{100}=\frac{2}{5}$$
The volume of B is 90 gallons.
The volume of the resultant mixture is (A + B).
What is the volume of A?
2) Use weighted average to find the unknown volume of A (steps can be combined)
$$\frac{2}{7}A + \frac{5}{9}(90)=\frac{2}{5}(A+90)$$
$$\frac{2}{7}A + 50=\frac{2}{5}A + \frac{2}{5}(90)$$
The following is multiple choice question (with options) to answer.
If milk is going to be measured, it can be measured in | [
"only a thin tube",
"only a round dish",
"any kind of shape container",
"only a square container"
] | C | Matter in the liquid phase has variable shape |
OpenBookQA | OpenBookQA-2600 | everyday-chemistry, ionic-compounds
If you don't count the proteins, epithelial cells and bacteria that normally constitute human saliva...how would this make saliva any different from a simple laboratory-prepared cocktail of sodium, potassium, magnesium, calcium, etc? Besides, ordinary (un-branded) bottled water would already contain these electrolytes; so by that logic, the water's already contaminated with your "saliva" even before you opened it!
The following is multiple choice question (with options) to answer.
Water needs to be clean in order for someone to safely drink it. Drinking polluted water is bad because it is the same as drinking | [
"poison",
"rocks",
"air",
"solids"
] | A | polluting means something poisonous is added to an environment causing harm to the environment |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.