source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-4301 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
Gloves over hands protect what from feeling | [
"the feet",
"the soul",
"nerves",
"the mind"
] | C | nerves can be used to feel heat and pressure on the skin |
OpenBookQA | OpenBookQA-4302 | earthquakes
Title: What is that spooky humming sound heard in earthquake footages? In most of the earthquake footages filmed outside during the earthquake that hit Mexico City on September 9, 2017 there was a distinctive streak of hum in rapid succession that could be heard in the background. It sounded like someone is constantly hitting the tuning forks onto a light tower like 2 times per second.
You can find numerous footages on youtube, but I picked one and fetched the audio portion covering the hums, you can listen to the audio at this link here (sorry I did not know how to upload an audio to SE).
Here is the waveform of the sound
What is that sound? What is causing this sound? If this was buildings or surrounding objects, why is there a pattern? Why is this sound heard in every footage no matter where they are filmed as long as they were filmed outside. Wailing sirens.
Examples 1, 2 where you see people come running out, i.e. exactly when you'd expect sirens, or 3, or 4 and 5 where they are explicitly mentioned.
The following is multiple choice question (with options) to answer.
When you scream in an empty room, you hear an echo due to the noise | [
"eating",
"bouncing a ball",
"nothing",
"bouncing off stuff"
] | D | echo is when sound reflects off of a surface |
OpenBookQA | OpenBookQA-4303 | photosynthesis, chloroplasts
Title: Chloroplasts in an animal cell What would happen if we inject a chloroplast organelle into an animal cell?
Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could there be photosynthesis in such a cell, or will some of the necessary mechanisms be missing? To answer your bigger question:
Yes, most of this is possible - under some conditions -, and animals and animal cells can acquire chloroplasts, and use them.
E.g.: see Elysia chlorotica whose cells actively take up chloroplasts and use them, and keep them alive (though not replicating). - Though some genes of algae are also contained in the Elysia chlorotica genome - which may be considered as partial replication.
Also there are salamanders that have replicating algae within them (since embryogenesis) - even algae (with chloroplasts) within animal cells - though here the algae might be rather understood as symbionts or "cell types", and the animal cells don't have the chloroplasts by themselves.
The following is multiple choice question (with options) to answer.
A cell can photosynthesize if it is | [
"a ferret's",
"a tern's",
"a willow's",
"a gila monster's"
] | C | animal cells can not perform photosynthesis |
OpenBookQA | OpenBookQA-4304 | threads, fasteners
Screws which form their own mating thread in another material are often two-start, as they have an additional resistance to unscrewing from the compression and roughness of the substrate they displaced around the threads. This is the case with some sheet metal screws, and also most wood screws.
The following is multiple choice question (with options) to answer.
Screws and bolts are needed to do what with a bike? | [
"eat it",
"cry",
"nothing",
"construct it"
] | D | a bicycle contains screws |
OpenBookQA | OpenBookQA-4305 | geology, geophysics, climate-change, carbon-cycle
We can see here in white numbers the most significant pre-industrial sources and sinks (at ~1000 years time scales). We can see that humans produce 9 Gigatons of carbon per year (GtC/yr), due to that extra inflow, photosynthesis is taking 3 GtC/yr more than before, and the ocean is taking an extra 2 GtC/yr as well. However, that is not enough to counteract the 9 GtC/yr we produce, and that is increasing the amount of carbon in the atmosphere at 4 GtC/yr. This means the level in the atmospheric "bath tub" is still rising.
If we were to keep those 9 GtC/yr we produce stable (i.e. not increasing production in the future). The concentration of $\ce{CO2}$ in the atmosphere will rise to a level high enough that the sinks will match the sources, for example with plants taking 5 GtC/yr and the ocean 4 GtC/yr, that would nicely balance the production. But that new equilibrium atmospheric $\ce{CO2}$ concentration would be high enough to rise Earth's temperature several degrees and force a whole reorganization of the Earth's climates.
Finally, we have to say that some of these $\ce{CO2}$ intakes, like the oceanic one, don't come for free, and have their own nasty consequences, like ocean acidification.
The following is multiple choice question (with options) to answer.
Which converts sunlight, water, and carbon dioxide to grow? | [
"a thing that flowers",
"a thing that goes around the Earth",
"a thing that flies in the sky",
"a thing that lives in caves"
] | A | a plant requires photosynthesis to grow |
OpenBookQA | OpenBookQA-4306 | biochemistry, botany, plant-physiology, photosynthesis
What are typical characteristics of different plants in this regard? I.e., how do common species of plants manage their C consumption before (and after) the development of leaves? There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which store energy in their bonds. That energy is then released when required to power other reactions, which is how a plant lives and grows. C is also incorporated into all the organic molecules in the plant.
Plants require several things to live: CO2, light, water and minerals. If any of those things is missing for a sustained period, growth will suffer. Most molecules in a plant require some carbon, which comes originally from CO2, and also an assortment of other elements which come from the mineral nutrients in the soil. So the plant is completely reliant on minerals.
Most plants, before a leaf is established or roots develop, grow using energy and nutrients stored in the endosperm and cotyledons of the seed. I whipped up a rough diagram below. Cotyledons are primitive leaves inside the seed. The endosperm is a starchy tissue used only for storage of nutrients and energy. The radicle is the juvenile root. The embryo is the baby plant.
The following is multiple choice question (with options) to answer.
What requires photosynthesis to grow? | [
"hills",
"planets",
"flora",
"people"
] | C | a plant requires photosynthesis to grow |
OpenBookQA | OpenBookQA-4307 | wasps
Title: Can wasps see under moonlight? It appears that the best time to attack a wasp nest is in the middle of the night. Their venom might terrorize us (my five-day old sting remains swollen and is starting to have red bumps in an area the size of a tennis ball), but at least our eyesight is superior. If we attack while they are asleep, or at least resting, we have our best chance of escaping unscathed—or so the online pundits claim.
The nest in question is at the edge between the wall and the roof protrusion. Because it is 8 feet off the ground rather than on the ground, it would appear to be a paper wasp nest. But because it is covered with paper and the individual cells are occluded, with the entrance at the bottom the only visible path leading inside, it may well be a yellow jacket nest.
Maybe it's futile to attack the nest in September. One might as well let them be. The nest will anyway be deserted in October when the temperature starts to freeze overnight. But it's never too early to prepare for next Spring.
I could choose a night when there is absolutely no light—not even moonlight—but then I myself would need to use a flashlight, providing them with the means of pursuing me. Or I could choose a full-moon, or near full-moon, night, and then I can see and they can, perhaps, not see.
Can wasps see under moonlight? No.... probably not... wasp cannot see at night... their scotopic vision{dim light vision} is not well develop so before sunset they return back to thier nest... so at night.. probably you can get them all together... rather then hunting for each indivisually...for reference https://sciencing.com/how-to-identify-wasps-bees-13406632.html hope it helps..
The following is multiple choice question (with options) to answer.
Nocturnal predators hunt when? | [
"sleep time",
"midday",
"morning",
"noon"
] | A | nocturnal predators hunt during the night |
OpenBookQA | OpenBookQA-4308 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
This animal thrives while the sun is down | [
"the bull shark",
"the snowy owl",
"the prairie dog",
"the spotted giraffe"
] | B | nocturnal predators hunt during the night |
OpenBookQA | OpenBookQA-4309 | biophysics, theoretical-biology, ecosystem
Systems ecology, especially with regard to energy and nutrient flow.
This type of ecology can be strongly influenced by physics. For one example see the book Theoretical Ecosystem Ecology: Understanding Element Cycles by Ågren & Bosatta (Ågren was originally a physicist)
Physical limitations to growth and transport
This can include for instance mechanical contraints on plant growth (see e.g. the book Plant Physics by Nicklas & Spatz), water transport in trees (see e.g. this BioSE question) or the biomechanics of movement (see e.g. Hudson et al (2012) on the speed and movement of cheetahs or Wikipedia: Biomechanics).
Allometric relationships between organisms, e.g. with regard to metabolism
To explain these types of relationships knowledge in physics is useful. See e.g. Kleiber's law for more.
MAXENT as a general approach to ecological patterns or to model species distributions
This is basically a tool lifted from physics that can be applied to ecological problems. There are many papers to look at, but Harte & Newman (2014) (Harte is another previous physicist) and Elith et al (2010) are two good starting points.
Dynamical modelling of populations and communities
This field use many of the same tools for analysis as physics, e.g. systems of differential equations. One of the pioneers in this field (among many) were Robert May (also started with a PhD in physics), and his classical book Theoretical Ecology: Principles and Applications is still a good starting point.
Energy harnessing and conversion by organisms
This can refer both to how organsims convert prey to energy (e.g. conversion efficiencies) and the physics of photosynthesis (which is an interesting intersection between physics and molecular biology). See Jang et al (2004) and O'Reilly & Olaya-Castro (2013) for examples of the how quantum mechanics can inform us about photosynthesis.
Hopefully this will give you a sense of some different ways that knowledge in physics can be useful for biology.
The following is multiple choice question (with options) to answer.
Which is least likely to be an ecosystem? | [
"the plains",
"the moon base",
"the desert",
"the fields"
] | B | the Earth contains many ecosystems |
OpenBookQA | OpenBookQA-4310 | evolution, botany, proteins
tl;dr: the egg contains more proteins than the seed because the chicken that made the egg ate a whole lot of seeds, and all the protein in those seeds ended up concentrated in that one egg.
EDIT: running into this much later I realized I missed a pretty vital half of the question, because there is a difference between fruits and seeds. The difference is the following: nitrogen is precious for plants so they'll try and use it for very important things. Seeds are very important to the plant, so while a seed has less protein than an egg it will still have lots of protein by plant standards. Fruits now, that's another story. Like the sugary nectar, fruits are a bribe for animals, a bit of food offered to them so that they'll spread the plant's seeds. And like with the sugary nectar, the plant has every incentive to pack that bribe full of cheap carbohydrates and as few precious proteins as it can manage.
The following is multiple choice question (with options) to answer.
Which contain seeds? | [
"mandarins",
"corn",
"carrots",
"potatoes"
] | A | fruit contains seeds |
OpenBookQA | OpenBookQA-4311 | immunology, bacteriology
Title: How do infectious bacteria determine when their numbers are high enough to attack a host? When you get sick, you generally don't contract enough bacteria at once for them to succeed in battling your immune system, right? Their numbers must gradually increase in the host's body before they know that they can attack. How does that work? I think the current answer to this for bacterial infections is quorum sensing. Quorum sensing is a signalling pathway in bacteria which senses a molecule that the bacteria themselves secrete. When the concentration of the quorum signal reaches a certain level, the bacteria interpret this as their population density reaching some threshhold.
Bacteria are always around - even infectious Staph, as described in the other answer, the bacteria are always being cleared out by the immune system, but when they find the right place where they can get critical mass, they dig in, form a biofilm and secrete toxins, which can help them divide more successfully.
This is a description of the process from a paper on Staph infection, a common bacterial infection in humans.
The following is multiple choice question (with options) to answer.
In humans, bacteria can help digest what? | [
"plastics",
"nutriment",
"copper",
"stones"
] | B | bacteria can help digest food in humans |
OpenBookQA | OpenBookQA-4312 | human-biology, physiology
Title: Why should or shouldn't we allow the human body to take its natural course? For example, when you are sick but don't feel thirsty, this could be due to baroreceptor reflex that is attempting to readjust salt and water balancing.
Why shouldn't a patient be left thirsty and let the body to adjust until he or she feels thirsty again? I am assuming that your question is: "why can a human intervention improve health?". Let me know if I misunderstood your question.
Why can a human intervention improve health?
Let's first avoid going into the details of your example. It is quite obvious that human intervention can often improve health in a way that your body alone cannot. To me, an intuitive way to classify the reasons why human intervention are important to improve health into two categories.
The body does not always react in an adaptive manner.
Example: Anaphylaxis is a serious and sudden allergic reaction that may cause death. An allergic reaction is what is happening when your immune system recognize a chemical as a infectious element while it is not. The reaction of the body is not adaptive and taking medication such as an anti-histaminic can force the body to stop this "stupid" reaction.
Note: There are reasons why the body cannot be always perfect but it is a bit long to make an overview here. There is stochasticity in the developmental processes, there is genetic variation for example due to always occurring deleterious mutations, there is also an arms race between parasites and host. This arm race leads parasites to take advantage of normal host physiological pathways. There are tons of other reasons that relate to the stochasticity and to the physic and physiological constraints of evolutionary processes.
The body sometimes cannot (physical constraint) produce the action that is required to be performed to improve health.
Example: If you have an important wound, then a human-made compression can by far improve your chance of the survival. The body is not able by itself to simulate this external compression to prevent blood to exit the body through the wound.
The following is multiple choice question (with options) to answer.
It is vital to your health to have a | [
"good time",
"jet ski",
"plane",
"colony of bacteria"
] | D | bacteria can help digest food in humans |
OpenBookQA | OpenBookQA-4313 | volcanology, volcanic-hazard, volcanic-eruption
Title: Would a Yellowstone eruption destroy global agriculture? Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither am I.)
Is that accurate?
Are there reasonable scenarios (i.e., not this) worked out for the effects of a supervolcano eruption?
I did see this question, where one of the commenters points out that such an event would be unprecedented, so our ability to predict is limited, but I'm still curious about whatever we do know at this stage. An eruption of the Yellowstone super volcano would cause agricultural disaster over a very large area. Its global effect would be significant, but not totally devastating.
The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.
But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.
Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.
Yellowstone last erupted 174 000 years ago, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.
The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is 660 ft. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.
The following is multiple choice question (with options) to answer.
An example of a change in the Earth is when a volcano, resembling a tall mountain, violently explodes and | [
"turns a deep crater into igneous rock and ice",
"gushes upward, revealing mounds of snow",
"drops downward, becoming a huge lake of lava",
"fills a deep crater with very hot water"
] | C | An example of a change in the Earth is an ocean becoming a wooded area |
OpenBookQA | OpenBookQA-4314 | human-biology, respiration
Title: Why does inert gas asphyxiation trigger unconsciousness almost immediately? According to an official safety bulletin from the U.S. Chemical Safety and Hazard Investigation Board:
"Breathing an oxygen deficient atmosphere can have serious and immediate effects, including unconsciousness after only one or two breaths."
Most people can hold their breath for at least 30 seconds and sometimes up to several minutes; clearly, breathing an oxygen-deficient inert gas will affect a person far sooner than simply holding one's breath.
An inert gas like nitrogen is not inherently toxic, so why does breathing a concentrated inert gas cause unconsciousness almost immediately? Does it replace the oxygen that would otherwise remain in the body while holding one's breath? One reason you can hold your breath for 30 or more seconds is that you are not denying your body oxygen during that time. Wikipedia says:
After exhaling, adult human lungs still contain 2.5–3 L of air, their functional residual capacity or FRC. On inhalation, only about 350 mL of new, warm, moistened atmospheric air is brought in and is well mixed with the FRC. Consequently, the gas composition of the FRC changes very little during the breathing cycle.
The following is multiple choice question (with options) to answer.
What typically occurs from a few seconds to under half of a minute? | [
"an hour",
"an earthquake",
"a television series",
"a volcano"
] | B | tectonic plates being pushed together causes earthquakes |
OpenBookQA | OpenBookQA-4315 | visible-light, reflection
Title: Why are reflected objects blurry? While this may seems like a strange question, I'll try to explain it the best I can. Like 75% of Americans, I wear glasses and contacts to correct my worsening vision. I'm not far sighted so objects in the distance appear blurry. I took my glasses off to look at my iPad. After doing so I noticed in the reflection of the glass, my lamp. The lamp is in the distance and looks blurry to me. But on my iPad's glass it was blurry unlike the rest of the objects on screen, including the glass which I could see clearly because I'm near-sighted. It is strange to me why the reflection was blurry even though it was close up. How can this be? This is simply the law of reflexion: if you trace a ray diagram for objects reflecting in your iPad screen, you are looking at light from a virtual image that is as far beyond your screen as the real source of light is from the iPad screen. So if the lamp is, say, 3 metres behind your shoulder, when you look at the iPad screen the reflected light is exactly like that from a lamp 3 metres beyond you iPad screen ahead of you. Put simply, you are looking at light diverging from a distant source, not from the iPad screen, so it will look blurry to you if a lamp that is really 3 metres beyond your iPad screen is blurry.
The following is multiple choice question (with options) to answer.
An object can be seen if it reflects light toward what? | [
"visual organ",
"eye spy",
"feet",
"brain"
] | A | if an object reflects light toward the eye then that object can be seen |
OpenBookQA | OpenBookQA-4316 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
Tendons work with what to move the bodies skeletal system | [
"wires",
"meat",
"robots",
"ropes"
] | B | muscles pull bones to move the bones |
OpenBookQA | OpenBookQA-4317 | pathology
Title: Are abrasions considered closed wounds? A closed wound is one where skin is intact and underlying tissue is not exposed to the environment.
Abrasion is an erosion of skin usually due to sheering force. In most cases the dermis is intact and the injury is superficial limited to epidermis. Abrasions heal without scarring by epithelialization.
Are abrasions considered closed wounds? I would think they are open wounds as the underlying tissue (which would be dermis in this case) are exposed to the environment. Please state the reason why they are classified into whatever group. The definition of closed and open wounds is variable. In histopathological terms (i.e. looking under a microscope) it is usually defined that a wound where the dermis is affected is open. In this case an abrasion is an open wound. This puts it in the same class as cuts (incisional/lacerations), tears and punctures. Closed wounds on the other hand are when the dermis isn't affected, such as in a haematoma (blood collection under the skin) or crush injury (extreme force typically for a long period of time) and contusions (i.e. bruises).
Medically they may be divided by management. Where open wounds are wounds which are likely to be contaminated and need thorough cleaning and may need antibiotic cover whereas closed wounds are ones that are very unlikely to be. In this case, abrasions may be considered a relatively closed wound as not all the protective layers of the skin have been breached (the dermis is not completely breached). Thus the physical barriers are relatively intact and continue to offer us defense against bacteria and organisms.
The following is multiple choice question (with options) to answer.
A scar will develop from a | [
"tap",
"slash",
"run",
"walk"
] | B | a scar is an acquired characteristic |
OpenBookQA | OpenBookQA-4318 | evolution, dna, natural-selection
It seems plausible to me that we (advanced life) could have a biological mechanism to "write" needed alterations into either our own DNA or our reproductive DNA over time, triggering the very specific evolutionary developments necessary to our survival without relying on random mutation.
My question:
Is this possible? Does any similar mechanism exist that we know of? If not, how can so many specific (advanced) evolutionary leaps be otherwise explained? This entire answer will be long, so read the short part first, then read the rest if you (or anyone else) is curious. Citations are included in the long section. I can include additional citations in the short section if needed.
Long Story Short
Your question touches on some common misconceptions about how the evolutionary process. Organisms don't "want" to evolve traits. Traits evolve through the biological processes of random mutation and natural selection.
Organisms do not "want" to evolve traits. (Well, OK, I'd love to evolve an extra pair of hands but that is not possible.) Natural selection works by modifying existing traits. Your turtle can stare all she wants at food out of reach but she will not evolve a longer neck. Instead, natural variation exists among neck lengths of the turtles because of variation of the genes that determine features related to overall boxy size. Those individuals with longer necks may be able to get a bit more food, live a little longer, and reproduce a little more. They will pass along their genes to their offspring, so perhaps more of their offspring will also have longer necks. Over many generations, the turtles may have somewhat longer necks.
A common misconception is that the traits of organisms are precisely adapted for a specific need. They are not, for a few reasons. First, natural selection occurs relative to the current environment. Adaptations that work well in one environment may not be so useful in another environment. Environments are rarely stable over evolutionary time so traits are subject to constant change.
Next, as mentioned above, natural selection can only work on what traits are present. While an extra set of arms would be handy, I am a tetrapod. My four appendages, along with the appendages of all other tetrapods, trace back to our common ancestor. The appendages of all tetrapods are modifications of that ancestral trait.
The following is multiple choice question (with options) to answer.
Which is likely to provide an undesired acquired characteristic for an organism? | [
"a light scratch on its leg",
"learning to leave the nest",
"finding a potential mate",
"dipping a foot in magma"
] | D | a scar is an acquired characteristic |
OpenBookQA | OpenBookQA-4319 | newtonian-mechanics, gravity, newtonian-gravity, acceleration, velocity
Title: Acceleration of a ball thrown into the air A ball sitting in a person's hand is at rest. The ball is thrown into the air. There must be some upward acceleration which is greater than the acceleration due to gravity, since in order for the ball to move, the upward force must be greater than the force of gravity. Since the mass of the ball doesn't change, the acceleration upwards must be greater than the acceleration downwards for the upward force to be greater than the downward force.
The instant the ball leaves the hand, what is its acceleration?
a. Acceleration of gravity, downward
b. Upward acceleration from the throw
c. Something else
The following is multiple choice question (with options) to answer.
As a soccer ball goes flying through the air, the person watching it knows that the reason is because | [
"everything is aerial",
"exerting occurred",
"balls are birds",
"soccer takes wing"
] | B | if an object is kicked then force is exerted on that object |
OpenBookQA | OpenBookQA-4320 | geochemistry, chemistry-in-fiction, minerals
Once you come up with a list of elements, you might want to ask the next questions in the Earth Science SE, not here.
The following is multiple choice question (with options) to answer.
To discover how tough a certain mineral may be, one would | [
"measure the weight of it",
"smash it to see the inside",
"attempt to leave a mark on it",
"see if it is able to be crushed"
] | C | if one mineral can scratch another mineral then that other mineral is softer than that one mineral |
OpenBookQA | OpenBookQA-4321 | Since we have $21$ terms taking $20$ possible values, there are some $0 \le i < j \le 20$ such that $S_i = S_j$. It follows that the total number of hours of study between days $i+1$ and $j$ (inclusive) is a multiple of $20$.
If it is not exactly equal to $20$ hours, then it must be at least $40$ hours. However, this is over a span of at most $20$ days. Dividing this into three periods of at most $7$ days (say the first week, second week, and third week), by averaging we find that she must have worked at least $14$ hours during one of the weeks, which is not allowed.
Thus she must actually have studied exactly $20$ hours between days $i+1$ and $j$.
• Yes, that's a little cleaner as route to Wiley's lemma.Thanks. – Joffan Jul 17 '16 at 23:05
• @Joffan, agreed. It's indeed cleaner to use 20 "holes" with 21 "pigeons" rather than separating $S_l=S_i+20$ as an individual case in my proof. Thank you, Shagnik. – Wiley Jul 18 '16 at 3:59
The proof consists of two parts.
• Part I: Prove that a period of $20$ days is enough such that there must exist some period of consecutive days during which totally $20$ hours are spent on studying.
• Part II: A counterexample which shows that $19$ days are not enough is presented.
Proof of Part I
The following is multiple choice question (with options) to answer.
24 hours is equal to one what? | [
"minute",
"day-night cycle",
"year",
"moment"
] | B | one day is equal to 24 hours |
OpenBookQA | OpenBookQA-4322 | food, decomposition
Title: Worm compost cannot have cooked food I live in the Netherlands and it is getting fashionable to compost with worms. After investigating a few websites I noticed that most websites suggested that I cannot feed the worms leftovers from citrus fruits. This seems logical. I then started noticing that people advise against feeding the worms cooked food.
I'm no biologist but I cannot imagine a reason why cooked food is bad for the worms. Could anybody explain why this might be in layman’s terms? There are a few reasons for not feeding cooked foods to worms (Eisenia spp.) in a smaller household size worm farm. It's not because the food is cooked but what it often contains.
The earthworm used in vermiculture is usually Eisenia fetida (red wigglers) though other Eisenia species are sometimes used. All Eisenia are epigeic species meaning they live in the junction of decomposing organic matter (such as leaf litter, aging manure, rotted fallen trees) and their natural food is decaying plant matter and bacteria that are also digesting the organic matter. They don't make use of small dead animals (meat and fat).
In large scale commercial vermiculture operations, leftover and past-due-date foods from restaurants, institutions, nursing homes and schools are used along with plant matter and carboard and paper. I'm not sure how they balance cooked foods but possibly much less is used than plant matter.
The fact food is cooked isn't the problem but what's in it and/or what happens to it when added to the bin. If you have leftover vegetables and fruit that's been cooked with no added salt, it's perfectly acceptable. A certain amount of sweetened cooked fruit is also fine as the worms will eat that too. But ready-made foods usually have preservatives, salt, fats and spices added. Either worms won't eat it, leading to odour caused by mouldy rotten food, or it can make them unthrifty and even killing off your worms if it's fed them repeatedly.
The following is multiple choice question (with options) to answer.
Which would likely decrease the food in an environment? | [
"gravity",
"water evaporation",
"a tree",
"time"
] | B | as available water in an environment decreases , the amount of available food in that environment will decrease |
OpenBookQA | OpenBookQA-4323 | transportation, fuel-economy, fuel
Title: Which is fuel efficient, roadways transport vs waterways transport? Which will be more efficient in term of fuel price:
Transport via roadways, say truck or motor vehicle.
Transport via waterways, say via ship or motor boat.
Assumptions:
Same caliber engines (same power) are used in either ways. Fuel is same. The distance is same for both water ways and land ways. The aim is to find which would be needing lesser Fuel, if both are travelling with same speed:
Considering real life scenarios, like considering friction on land and turbulence in water. From the European Environment Agency - Rail and Waterborne cited in Jon Arnt's answer:
Chart shows gm CO2 / tonne km.
For my preceived interpretation of the question. The best way to ship cargo on land would be rail at 24 gm, then Inland WaterWays at 33gm, which are significantly better than heavy goods vehicles at 137gm.
But for shear mass of cargo the best way is via ships. 7gm would correspond to container ships.
From EEDI Explained
Even generic cargo vessels >400 gt produce less than 30 gm CO2 / tonne nautical mi. 1 nautical mi = 1.852 kms. Larger the vessel the less polution is produced per tonne of cargo.
Carbon Calculator Emission Factors from CN (Canadian National) railway report: 2.5-6 gm CO2e/tonne-km for bulk carriers; 8.3 gm CO2e/tonne-km for containerships; 12.1 gm CO2e/tonne-km for rail; and 63.4 gm CO2e/tonne-km for trucks.
If there is a water path, cargo transport consumes significantly less fuel than a road path.
The following is multiple choice question (with options) to answer.
which form of transportation has zero emissions? | [
"motorbikes",
"speed boats",
"hybrid cars",
"pedal bikes"
] | D | riding a bike does not cause pollution |
OpenBookQA | OpenBookQA-4324 | humidity, air-pollution
Title: Does usual city pollution have effects on relative humidity? I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity? By way of reference, "humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature".
From the information you have supplied in your comments. There are waters in Bucharest and forests in the suburbs, but no waters or forests where the country house is located.
From your information, Bucharest has a number of sources of atmospheric water vapour, the river that flows through it (evaporation of water) and the forests in the suburbs (transpiration of water). Additionally, motor vehicle exhausts will increase the humidity as water vapour is one of the products of the combustion of hydrocarbons.
The warmer the air, the greater its capacity to hold moisture. Cities tend to be warmer than rural areas due to the heat island effect, which is the result of modifying land surfaces and the generation of waste heat.
Humidity in the rural location will arise from evaporation of water in the soil and transpiration from crops or grasses. Such transpiration will produce less water vapour than forests. Additionally, the rural location will have significantly fewer cars producing water vapour in their exhausts. Consequently, the rural location will be less humid than the city.
The reason why Bucharest is more humid that the rural location has more to do with the greater availability and vaporization of water in Bucharest and the temperature of Bucharest than the amount of pollution in Bucharest.
The following is multiple choice question (with options) to answer.
Which of these is less likely to cause pollution | [
"mountain bike",
"motor bike",
"dirt bike",
"chopper"
] | A | riding a bike does not cause pollution |
OpenBookQA | OpenBookQA-4325 | ecology
Title: Do invasive species cause long-term damage to ecosystems they invade? Growing up in the U.S., I was warned at various times of the dire consequences of a variety of introduced pests (usually insects).
Japanese beetles, gypsy moths, and most recently the brown marmorated stink bug are all introduced pests that, at various times, were described as serious threats to our ecology.
These threats aren't confined to arthropods, either. The giant African land snail is causing a stir in Florida (indeed, Florida seems to suffer from an excessive variety of introduced species.
"Lack of native predators" is frequently cited as the primary reason many invasive species are considered such a risk to the ecology.
I understand that these introduced species can place tremendous pressure on native species that fill similar ecological niches, and may even push these species out of the region due to competition for food and habitat. However, do the overall ecologies that these species are introduced to adjust over long periods of time?
The numbers of Japanese beetles and gypsy moths don't seem anywhere as high as when I was a child. Has the ecosystem adjusted, or has the overpopulation self-corrected as the species ran low on food through over-consumption? Or are the populations still just as problematic now as they were 30 years ago, and I just am not seeing the bigger picture?
What is the long-term impact that we've seen from invasive, introduced species? Is there a significant difference on the long-term impact between introduced flora, arthropods, or mammals? The answer really depends on how you think of invasive. One extreme answer is to say that all things are relative, and that the concepts of local and invasive are all relative. This matters to a certain extent because ecologists draw a fuzzy line between invasive and naturalized. You could start with some basic species that we all think of as either good, local, or neutral. Take the earthworm. Most people think of it as a common native species, but the earthworm is actually an invasive species that has radically changed much of North America that came over with the Europeans. Similarly, brown trout are also invasive, coming to the US in the 1800's.
The following is multiple choice question (with options) to answer.
Which would likely be to blame for removal of habitats? | [
"a zoo",
"a mall",
"a wildlife charity",
"a rabbit"
] | B | if a habitat is removed then that habitat is destroyed |
OpenBookQA | OpenBookQA-4326 | evaporation, humidity
Title: Confusion understanding relative humidity levels I have difficulty in understanding how can the relative humidity of a mixture of air and water can be 100%. I understand that places like where i live have high relative humidity, so the place is more humid (rain forest) than deserts, for exemple. But an evaporator, in an air conditioning system, removes the water from the air passing in and elevates the relative humidity of it. So why does a mixture containing, for example, 50% of relat. humidity can lose water mass from it and have a highier relat. humidity level?
Thanks :) For a given temperature and pressure, there is a maximum amount of water vapor which can exist in gaseous form. Any greater concentration will cause some of the vapor to condense. Measuring the absolute amount of vapor in the air produces absolute humidity, which is not expressed in per cent.
Relative humidity, however, is the amount of water vapor relative to the theoretical maximum at that temperature and pressure - that's why it's called relative. It is defined as the ratio of the two concentrations expressed as a percentage. So if the air contains the maximum amount of water vapor that it can hold without any condensing, the relative humidity is, by definition, 100%.
The following is multiple choice question (with options) to answer.
moist means high in what? | [
"rock",
"solids",
"watery",
"heat"
] | C | moist means high in moisture |
OpenBookQA | OpenBookQA-4327 | newtonian-mechanics, inertia
Title: How would I move if I grew by a factor of 3 in each physical dimension? Suppose, for the sake of this thought experiment, I am structurally identical to an average human, with the only difference being that my body is scaled in all directions by factor of 3. This would result in me having 27x more mass than a normal human.
In cinema, giants tend to move very sluggishly, and that seems to match our expectation of creatures of that size--after all, most people think of whales and elephants as being very large, slow-moving creatures.
However, I now also have 27x more muscle mass... Wouldn't my much larger muscles provide the necessary force to counteract the increase in inertia?
Barring a slight increase in air resistance, wouldn't my body movements (walking, running, moving my arms) be indistinguishable from that of a normal-sized human, and not sluggish as depicted in movies? Assuming for a moment that your bones are proportionately stronger... (because you are asking about motion, not strength: but see for example this question about scaling in nature) That still leaves us with some physics that "doesn't scale well".
First, there is the issue of muscle mass: assuming your muscles are made of the same fibers, their strength (ability to exert a force) goes as the cross sectional area, while their power (force times velocity) scales with the total volume (if each element of muscle contracts by some amount, the total contraction of the muscle, and thus the velocity, depends on the length; and since the force depends on the cross section, the power scales with the volume; this also makes sense from an energy balance perspective, assuming that each cell expends a certain amount of energy per unit time, the total power will scale with the number of cells). So you are not actually "27 times stronger" when you are scaled up - your ability to accelerate yourself is less than if you were your normal size.
The following is multiple choice question (with options) to answer.
Why would a bear eat so much that his fat wobbles when he walks? | [
"so that other animals can have fun jumping on his belly",
"because he feels depressed",
"to be a bigger target for hunters",
"to prepare for the snowy season"
] | D | fat is used to keep animals warm |
OpenBookQA | OpenBookQA-4328 | 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.
Which of these animals could keep itself warmest? | [
"a squirrel",
"a whale",
"a chihuahua",
"a cat"
] | B | fat is used to keep animals warm |
OpenBookQA | OpenBookQA-4329 | botany
Title: Do plants absorb toxins from the soil? Consider a plant like Aloe Vera that grows up in a toxic environment where the concentration of pesticides, and materials like lead, mercury, cadmium, arsenic etc is very high(e.g. Marshland dumping yard ). Would that mean that the extract from these plants would contain all these toxic elements. Not "all of them". But yes, plants suck up water from the soil, with everything dissolved in this water - nutrients, heavy metals, poisons. And also they breathe air, and absorb stuff via this route.
There probably are some toxins which will not enter the plant, because their molecules are too large and/or fragile. For example, should a plant root come in contact with snake venom, I cannot imagine that any venom will end up stored in the plant leaves.
Plants also have their own metabolism, so they will change/deactivate some toxins. I've seen claims that some plants "purify" formaldehyde, although I don't trust the sources enough to be sure of that.
But the smaller the poison molecule, and the less similar to stuff which is usually digested in nature, the more likely that it will enter the plant and stick around instead of being broken down. The heavy metals you mentioned are prime candidates. If they are present in the groundwater - or also lead from air pollution, before we banned leaded gasoline - they end up in plants, including food plants. And mushrooms are even more at risk.
Growing food near waste dumps is a known problem in farming, and sometimes makes the news, for example here:
http://bigstory.ap.org/article/mafia-toxic-waste-dumping-poisons-italy-farmlands
The following is multiple choice question (with options) to answer.
Plants expel a gas that | [
"is poisonous to humans",
"is used to make balloons rise into the air",
"humans exhale as well",
"our circulatory system spreads to our body from our lungs"
] | D | the circulatory system brings oxygen from the lungs to the rest of the body |
OpenBookQA | OpenBookQA-4330 | zoology, circulatory-system, heart-output, amphibians
I would add to this my notes from when I was a biochem student (but studied Zoology), mentioning the arterial cone and a spiral valve. This is better described in Britannica:
The conus arteriosus is muscular and contains a spiral valve. Again, as in lungfishes, this has an important role in directing blood into the correct arterial arches. In the frog, Rana, venous blood is driven into the right atrium of the heart by contraction of the sinus venosus, and it flows into the left atrium from the lungs. A wave of contraction then spreads over the whole atrium and drives blood into the ventricle, where blood from the two sources tends to remain separate. Separation is maintained in the spiral valve, and the result is similar to the situation in lungfishes. Blood from the body, entering the right atrium, tends to pass to the lungs and skin for oxygenation; that from the lungs, entering the left atrium, tends to go to the head. Some mixing does occur, and this blood tends to be directed by the spiral valve into the arterial arch leading to the body.
The following is multiple choice question (with options) to answer.
Which likely is using its circulatory system? | [
"a tree standing in the woods",
"a horse after a race",
"a car during an auto meet",
"a rock down to the molecular level"
] | B | the circulatory system brings oxygen from the lungs to the rest of the body |
OpenBookQA | OpenBookQA-4331 | water-resources
Location
This plant requires a hot location with large area of cheap land by the ocean and a relatively consistent wind.
Stage 1 - Wave Pump
A wave-powered pump raises sea water into a large lake on land. Here is an example of a direct wave-powered pump, other types of wave power harnessing typically convert mechanical motion into electricity. However, that motion can be easily used to directly drive a pump.
Stage 2 - Evaporation Lake
The evaporation lake is a large shallow area, covered in a greenhouse-like way to aid evaporation. The sea-water flows away from the ocean along channels in the lake-bed then back again towards the ocean in the next adjacent channel where it drains back into the sea. This prevents the build-up of deposits as the returning sea-water will take them with it and return to the sea more concentrated. The roof may contain Fresnel lenses or other solar concentrators to help evaporation.
A wind-catching tower blows air across the lake to lower air pressure and aid in evaporation. This tower could be like those used in Masdar City, or a standard wind turbine tower with either electrical or direct transmission to a series of fans. The result is a continuous airflow across the lake which carries the water vapor to the far side where it is channeled up a wide column into the next stage.
Stage 3 - Condensing Tower
The water vapor is channeled up a large column to a condensing chamber high on the tower. Here, a series of fins are cooled by a heat-pump driven directly by a wind-turbine on top of the tower. the water condenses on the fins and drains into a fresh-water tank near the top of the tower.
Stage 4 - Power Generation
The water from the condensing tower is lowered to a height suitable for a standard water-tower through one or more water turbines to generate power.
Stage 5 - Filtering and treatment
The salty sea-air will also condense on the fins, and there may be small airborne particles and particles from wear on stages within this process that get into the water, so it will probably need further filtering and treatment to make it drinkable. Some of the power from the water turbine may be used for this.
There you have it, you have clean water, above ground level so pressure is already available, and hopefully some excess electricity and cool dry air as by-products.
The following is multiple choice question (with options) to answer.
Where's the best place to use water to power a lighthouse? | [
"the tundra",
"the ocean",
"the desert",
"the mountains"
] | B | tidal energy can be used to produce electricity |
OpenBookQA | OpenBookQA-4332 | food, nutrition, energy-metabolism
Title: What are the bare minimum nutrients required to survive as a human? I am trying to determine the bare minimum nutritional requirements to survive as a human, ignoring energy (caloric) requirements. Another way to ask this question is: What elements can humans not live without? I am not inquiring solely about what nutrients are needed, but also their approximate amounts.
Imagine pills that a person can take that covers all their base nutritional needs and that after taking this pill the person can eat whatever they want to meet their caloric requirements. Hypothetically, this pill could have some amount (how much?) fat, carbohydrates, protein, fiber, minerals, and vitamins, and the person could subsequently eat any other food to meet their caloric requirements knowing their nutritional needs would already be otherwise met. Lets ignore the possibility of the person suffering from health issues due to eating too much of any specific food to meet their caloric requirements (e.g., taking the magic pills and then eating only butter).
A person in this situation could think "Ok I've got most of my bases covered, now I just need to ingest another 1000 calories of (almost) anything I want).
What nutrients are absolutely necessary for humans to survive indefinitely, and how much of these nutrients are required?
I am hoping for a complete list with approximate amounts (e.g., 20g fat, 20g carbohydrates, 1mg Vitamin X, .05mg Vitamin Y, 10mg mineral X). Essential nutrients include (NutrientsReview):
Water
9 amino acids: histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, tryptophan, threonine, valine
2 fatty acids (alpha linolenic and linoleic acid)
Vitamins: A, B1, B2, B3, B5, B6, folic acid, biotin, B12, C,
D, E and K (and choline, which is considered a vitamin-like substance)
Minerals: calcium, chromium, chloride, copper, iodine, iron,
manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc
The following is multiple choice question (with options) to answer.
What requires energy for survival? | [
"air",
"giraffes",
"rocks",
"sand"
] | B | living things all require energy for survival |
OpenBookQA | OpenBookQA-4333 | photosynthesis, respiration, ecosystem, decomposition
Maybe you should study the metabolic processes of plants and life in general to better understand this. All life consists of chemical reactions that build up structures; in order to build them up you need energy (because of the second law of thermodynamics), and all living things create that energy by breaking down complex molecules into simpler ones. (as such it would be more accurate to say that all life consists of chemical reactions that build up and break down various structures). You might be wondering "but what about the difference between autotrophs and heterotrophs I heard about"; the difference between those is where they get the complex molecules from in the first place. Autotrophs use a different source of energy to build them up while heterotrophs get them from their environment. As such, you can think of every living thing as being made of two kind of molecules: those that actually form their structure (in humans, the molecules that make up cell membranes, bones, muscles, etc) and those that are stored in order to be broken down to power the whole system (in humans that's fat, glycogen, glucose, etc). Of course a molecule can do both; if you're starving your body may start to break down structural molecules for power. There are many different ways of breaking down those big molecules for power; the most efficient one, that starts with a big chain of carbon atoms and cuts it down into individual CO2 molecules using O2 molecules, is called aerobic respiration (i.e. respiration that uses oxygen).
Because those complex molecules are required to power all life, autotrophs (the organisms that actually make them) are very important, and the processes they use to make them are very important too. The process that makes almost all of the molecules that power almost all life on earth is photosynthesis, which uses the energy from the sun to power a reaction that converts CO2 from the atmosphere into big carbon-based molecules we'll call carbohydrates. This is called "fixing carbon", since the carbon atom is the most important one; measuring how much photosynthesis is happening is another way of measuring how many carbon atoms move from being part of a CO2 molecule to being part of a plant.
The following is multiple choice question (with options) to answer.
Living things all require energy for what? | [
"dying",
"observing",
"staying perky",
"decaying"
] | C | living things all require energy for survival |
OpenBookQA | OpenBookQA-4334 | genetics, botany, reproduction, dendrology
So why I don't get the apple-tree of the scion kind if I plant the seeds from an apple which has grown on such a tree? I would expect that the genes in the apple seeds must be the same. However if I plant the seeds, I have to graft the new seedling again. The reason most apples are produced from grafted trees is that apples don't breed true.
In a large number of crops, you have "lines" of crops. Basically, if you breed two plants of the same cultivar together, their offspring are similar enough to both parents that it performs like the parents. The reason for this is that these crop lines have been interbreed with each other for long enough that the population is self consistent, and the important alleles are present in frequencies that mean all progeny are likely to inherit them.
However, the types of apples which are sold commercially are not from these sorts of cultivar lines. Instead, they've been obtained from "sports". That is, the chance production of either a particular hybrid gene set, or sometimes from random mutations that happened on an adult tree of another apple variety. For example, the Granny Smith occurred from a chance seedling which was discovered by Maria Ann Smith.
These apples don't necessarily have "consistent" alleles. For example, it may be heterozygous for certain genes. If you have Aa alleles at one gene, if you self-pollinate the plant, you're going to get a mix of AA, Aa and aa genes in the offspring, the last of these isn't going to be the same phenotype as the parent. Now recognize that this is happening at multiple genes across the entire genome, so there are many chances to get non-parent-like allele combinations. Add to this the issue of co-dominance, where the heterozygote has a different phenotype than either homozygote (that is, BB isn't like Bb), and the chances that an offspring has a gene with a non-parent like allele combination is pretty high.
There's a further complication that some apple varieties like Honeycrisp are self-sterile. Even if Honeycrisp could theoretically breed true, there's no way for it to fertilize itself, meaning that all fertilization events are hybridizations.
The following is multiple choice question (with options) to answer.
If a bean is a mile away from where it originated , and then it develops into a plant which produces more beans, then that original bean most likely | [
"was flat",
"was built",
"was honest",
"was transported"
] | D | plant requires seed dispersal for reproduction |
OpenBookQA | OpenBookQA-4335 | reproduction, asexual-reproduction
Title: can self-fertilization in flowers be called asexual reproduction? Suppose a flower having both male and female reproductive parts is self-fertilized then can this be called asexual reproduction...?I'm quite confused cause in this case the fusion of male and female gametes do take place but again the gametes are from the same parent....please help. According to this article from Berkeley, asexual reproduction is:
Any reproductive process that does not involve meiosis or syngamy
Using this definition of asexual reproduction and knowing self-fertilization involves meiosis and syngamy, it is not asexual.
The following is multiple choice question (with options) to answer.
Reproduction occurs when? | [
"infancy",
"childhood",
"youth",
"physically prepared"
] | D | reproduction occurs during adulthood |
OpenBookQA | OpenBookQA-4336 | meteorology, tropical-cyclone, extreme-weather
Title: Why would Google's map of areas affected by Hurricane Harvey have advisories for the west coast and other far away areas?
What behavior of this hurricane would lead to advisories for the west coast and even parts of Canada and Alaska, when the hurricane is in the South?
I have little experience in meteorology or any of the earth sciences really, so I am interested in how this would affect the weather or other conditions far away from where the hurricane is severe. It seems like there is more than just a hurricane going on. According to the National Weather Service there are excessive heat advisories, gale warnings, etc.
The following is multiple choice question (with options) to answer.
Which is likely true of hurricanes? | [
"a category 50 hurricane becomes a category 1 hurricane over land",
"a category 5 hurricane becomes a category 11 hurricane over land",
"a category 5 dies over land",
"a category 0 hurricane becomes a category 1 hurricane over land"
] | C | when a hurricane moves over land , that hurricane will decrease in strength |
OpenBookQA | OpenBookQA-4337 | visible-light, everyday-life, shadow
This is simple to tackle mathematically. When the sun is directly behind/in front of the turbine, the coordinates of a particular blade are transformed as follows when projected onto the ground:
$$ R(\cos(\theta),\sin(\theta))\mapsto R(\cos(\theta)/\tan(\alpha),\sin(\theta)) $$
as is shown above. The elongation is even greater when the sun is at a horizontal angle with respect to the normal of the blades, but I shall ignore this effect for simplicity.
While the velocity of an actual blade ($R\dot{\theta}$) is constant, its projection has a velocity that depends on the angle $\theta$,
$$ v=R\dot{\theta}\sqrt{\frac{\sin^2(\theta)}{\tan^2(\alpha)}+\cos^2(\theta)} $$
and so it follows that the shadow speed varies.
For example, here is a plot of the relative tangential velocity of the shadow as a function of $\theta$ when the sun is relatively low in the sky ($\alpha=\pi/6$):
The following is multiple choice question (with options) to answer.
as a source of light moves directly overhead of an object , the size of the shadow of that object will do what? | [
"increase",
"plummet",
"rise",
"grow"
] | B | as a source of light moves directly overhead of an object , the size of the shadow of that object will decrease |
OpenBookQA | OpenBookQA-4338 | electrical-engineering, ethics, sales, safety
But all of those steps are going way above and beyond what you're obligated to do in this particular case. This is especially so when there is a safe usage for the product along with an unsafe approach. And any of those actions are likely to irreparably damage your relationship with that client. Damaging the relationship will impair your credibility with them and make it less likely that they'll listen to your concerns.
So your obligation is to lay it out to them in unambiguous terms that you believe they need to stop using the product in their "preferred" manner and that your firm will no longer provide any support whatsoever regarding future use of that product in that configuration.
The following is multiple choice question (with options) to answer.
If someone wants you to stop, they want you to | [
"be fast",
"eat cheese",
"be slow",
"be still"
] | D | stopped means no speed |
OpenBookQA | OpenBookQA-4339 | physical-chemistry, thermodynamics, polymers
Title: Is temperature of crystallisation same as melting point temperature for polymers? Melting point tends to be a temperature range. Is it true that the temperature of crystallisation is the highest temperature at which the polymer melts and thus there is some distinction between temperature of crystallisation, Tc and temperature at melting point, Tm?
Is temperature of crystallization same as melting point temperature for polymers?
In a word: NO.
If you undrestand what the glass transition, crystallization and melting temperatures are it will make sense why they are not the same. This paper does an excellent job at explaining the three concepts but I will summarize.
The glass transition temperature is the temperature where polymer chains become sufficiently mobile that the material transforms from being brittle to being soft and plastic (neither exo- nor endothermic, but does the heat capacity does increase). The crystallization temperature is the temperature where the molecules are mobile enough to rearrange into ordered arrangements (crystallize not decrystallize; this is an exothermic process; see plot below). The melting temperature is where the polymer chains can freely move and ordered arrangements are disrupted (this annihilates any prior crystallization; an endothermic process).
Source: Plastic Technology Laboratories
The following is multiple choice question (with options) to answer.
Melting point means temperature at which a solid does what? | [
"flys",
"gets melty",
"floats",
"sinks"
] | B | melting point means temperature at which a solid melts |
OpenBookQA | OpenBookQA-4340 | The bit of ejected fuel carries some momentum from the vehicle. The mass, inertial observer velocity, and momentum of the exhaust are
$$\Delta m_e(t) = \dot m_f(t)\,\Delta t$$
$$\vec v_{e_{\text{inertial}}}) = \vec v_r(t)+\vec v_e(t)$$
$\Delta \vec p_e(t+\Delta t) = \dot m_f(t)\,\Delta t\, (\vec v_r(t)+\vec v_e(t))[/tex] The momentum of the rocket+exhaust at the end of the time interval is thus $$\vec p_{r+e}(t+\Delta t) = (m_r(t) -\dot m_f(t)\,\Delta t)\, (\vec v_r(t)+\Delta \vec v_r(t)) + \dot m_f(t)\,\Delta t\, (\vec v_r(t)+\vec v_e(t))$$ Dropping the second-order term [itex]\Delta t \Delta \vec v_r(t)$ and simplifying,
$$\vec p_{r+e}(t+\Delta t) = m_r(t)\,\vec v_r(t)+ m_r(t) \, \Delta \vec v_r(t) + \dot m_f(t)\,\Delta t\, \vec v_e(t)$$
The following is multiple choice question (with options) to answer.
A rocket's movement is most like a | [
"rock",
"house",
"bag of gas",
"stone"
] | C | a rocket engine is used to produce thrust by pushing gases out at a high speed |
OpenBookQA | OpenBookQA-4341 | species-identification, zoology, marine-biology, ichthyology, bone
Title: Identification of a strange skull My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it? Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site).
I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is indeed a neurocranium.(source of the picture).
Thank you all for your help!
The following is multiple choice question (with options) to answer.
One of tunas favorite prey is the | [
"shark",
"hummingbird",
"cat",
"sardine"
] | D | tuna eat fish |
OpenBookQA | OpenBookQA-4342 | experimental-chemistry
Pouring the copper sulfate solution into the beaker resulted in a vigorous reaction and quite a bit of heat. I stirred the reaction mixture and let it go to completion. The magnet still stuck strongly to the bottom of the beaker, indicating that there was still substantial powdered iron remaining.
The mixture was decanted to another beaker, with some mostly useless filtering (no good filter paper at hand), and allowed to settle for about an hour. The copper particles produced in the reaction are very small and settle out very slowly. Some of the supernatant solution was transferred to a sample cell, illuminated from the left via an LED flashlight and photographed. This is shown in the next figure:
Despite the light scattering, the green color of the ferrous sulfate solution is evident. The photo will be updated after more particulate has settled out.
The following is multiple choice question (with options) to answer.
Iron sticks to | [
"a ceramic throne",
"a fridge",
"a vitamin",
"a beanie baby"
] | B | if something contains a large amount of magnetic material then that something will attract magnets |
OpenBookQA | OpenBookQA-4343 | electromagnetism, electricity, electrons, atoms, voltage
1Actually, electrons are also small magnets themselves (they have an instrisic quantum-mechanical spin) and therefore are attracted to inhomogenic magnetic fields, but that's quite another issue.
2Actually, it would... but that's mostly relevant in the high-frequency-regime, i.e. bound electrons that jiggle back and forth very quickly.
The following is multiple choice question (with options) to answer.
Which of these objects would attract a magnet? | [
"a door handle",
"a light bulb",
"a pillow",
"a baseball"
] | A | if something contains a large amount of magnetic material then that something will attract magnets |
OpenBookQA | OpenBookQA-4344 | gravity, fluid-dynamics, education, popular-science, bubbles
Now if the bubble becomes smaller, the air molecules will push it out again. If the bubble becomes bigger, the water molecules will push it in again. So the bubble can't change shape. You can see this in a balloon (thanks to Bobson). Take an empty balloon. It is very small because the rubber is pulling the balloon together, and there is no air in the balloon to push it out. Now if you inflate the balloon, more and more air will get inside. So the air will push out harder and harder, making the balloon bigger. If you poke the balloon, you can feel the air pushing against your finger. And if you take your finger away again, the air pushes the balloon back into shape. This is exactly the same as in a bubble. Except the water will 'break' much easier then the rubber in the balloon. So you can't really poke it.
So just like the die, the bubble and the balloon want to be in a specific shape. This means the bubble can only move as a whole. The die couldn't slide off your hand because of friction. With the bubble something similar is happening:
Hold your hands in a cup and throw some water in. Now open your hands. The water flowed off your hands, but some of the water is still sticking to your hand. This is because the molecules in the water and the molecules in your hand are pulling on each other too. It's called adhesion. Because of this adhesion between the water at the bottom of the bubble and your hand, the bubble can't slide off your hand, just like the die.
The following is multiple choice question (with options) to answer.
If you flick an empty glass of water with your finger it will | [
"fill up",
"burst in flames",
"make a sound",
"evaporate"
] | C | vibrating matter can produce sound |
OpenBookQA | OpenBookQA-4345 | python, skyfield
Now the problem is that t0 is set on November the 1st, but the rises_and_settings function does not return any result before the Novembre 4th.
Why is that? The rising-setting search routine is currently optimized for objects near the celestial equator, like the Sun, Moon, and planets, that spent about half the day in the sky. This assumption lets it search in ¼-day increments, making it more efficient for such objects.
But the Andromeda galaxy and your observer position are both far to the north of the ecliptic, such that the galaxy spends only (if I'm doing the math in my head correctly, given the output you posted) about 4 hours below the horizon each day. It's easy for Skyfield to miss that 4 hour window when it’s stepping forward in ¼-day = 6 hour steps looking for the galaxy to be below the horizon.
Maybe Skyfield should someday have more intelligence around risings and settings! For now, you can tell it to search a tighter collection of points:
rise_set.step_days = 0.1
If you put that before your call to almanac.find_discrete(), I believe you will find that it computes all of the galaxy’s risings and settings!
The following is multiple choice question (with options) to answer.
What rises and sets causing cycles of day and night? | [
"the closest gas giant planet",
"another galaxy near ours",
"the closest planet to earth",
"the closest yellow dwarf star"
] | D | the sun rising and setting causes cycles of day and night |
OpenBookQA | OpenBookQA-4346 | the-moon, the-sun
Title: Sunrise and Moonrise time are same I checked an app and saw that today, the sunrise and moonrise time are almost same. The sunset and moonset time are also same.
Why does this happen?
I have always known that moon rises at night and sets at dawn. That's called New Moon and happens roughly once a month.
It's when (viewed from earth) the moon, circling the earth, is in the same direction as the sun. So, by rotation of the earth, both become visible (sunrise/moonrise) and invisible (sunset/moonset) at roughly the same time.
Moon is then hardly visible for two reasons:
The back side of the moon is lit by the sun, the side facing to us does not get sunlight.
The moon is visibly rather close to the sun, so sunlight will blind the human eye when looking in that direction.
Two weeks later, we have Full Moon, the moon is opposite to the sun, it rises when the sun goes down and goes down when the sun rises, meaning that it's visible at night. And the side facing us gets full sunlight, so the moon becomes a very bright object on night sky.
The following is multiple choice question (with options) to answer.
When the sun rises, there is light and it is daytime. When is it night time? | [
"when its blue and Pink",
"when its down and lightless",
"when its seven and eight.",
"when its dead and gone"
] | B | the sun rising and setting causes cycles of day and night |
OpenBookQA | OpenBookQA-4347 | organic-chemistry, spectroscopy, analytical-chemistry, nmr-spectroscopy
Obviously there is some guess work in here and if it was an important project I'd do some further experiments and look for some additional model compounds in order to confirm these assignments and remove the discrepancies, but this is a good start.
The following is multiple choice question (with options) to answer.
It's important to do this if you want your lab experiment to be performed correctly. | [
"do the experiment blindfolded",
"comprehend all the steps that will be involved beforehand",
"forget about rules and wing it",
"do all the steps in a random order"
] | B | performing lab expiriments accurately requires understanding all directions beforehand |
OpenBookQA | OpenBookQA-4348 | statistics
Title: The danger of "amplifying noise" A data scientist cautioned me against "just amplifying noise" in a data analysis. What did he mean? Can you explain and/or point to resources explaining the problem? There is very little information in this question. I will try to answer this in the most generic sense. Let's start by defining Noise. Noise here as you probably know is unwanted data. Any data which you are not looking for while evaluating a problem or scenario can be considered as noise.
Examples for amplifying noise:
Amplifying noise might occur in cases and scenarios where there is a small data set and you are trying to supersample the dataset or another example could be while working with waveforms. In order to detect weaker signals.
Disadvantages of Amplifying noise
The biggest disadvantage of amplifying noise from a data science perspective is that the model used to perform various operations on the data such as Regression, Classification etc will be less efficient. For example having noise based on supersampling in Classification may affect the model. If we were to use decision trees for classification you might create a bias in the algorithm which just pertains to noise while training. So your accuracy for classification also decreases. Similarly, in regression when you train with noise you might choose a wrong model because the noise alters the goodness of the fit.
The following is multiple choice question (with options) to answer.
An unwillingness to listen to guidelines leaves data completely | [
"noble prize winning",
"faulty",
"repeatable",
"perfect"
] | B | performing lab expiriments accurately requires understanding all directions beforehand |
OpenBookQA | OpenBookQA-4349 | identify-this-object
Title: How to figure out what something in the sky is? A while ago I saw something in the sky early in the evening. At first, I thought it was a plane since it seemed far too bright to be a star - no other stars could be seen. However, it didn't move, so I ruled out that possibility.
It seemed to be relatively close to the horizon so I considered if it was a very high pole with some sort of light at the top, but after I walked for a few kilometres it was still at the same location.
During the few hours I looked at it, it moved a bit across the sky.
I considered a satellite, but it didn't seem to move quite enough of what I anticipated a satellite would move.
Since then, I have seen it every evening when I remember to look for it.
Apart from this object only the moon could be seen. To me, it seemed like the moon moved in the same arched way across the sky as the object, but I could be wrong on the.
I have seen several questions on this site where someone asks "what was it?" which has been closed with "too broad". So I am not going to ask what it was.
Instead I am curious about what I can do to figure out what it is? Which observations is relevant to make when looking at such objects? As someone who is curious about the sky, but does not have any instruments for doing any actual measurements can I actually do anything?
The first picture shows the object in the sky.
The second picture shows the same object, but where I have indicated the arch the object moved in as well as the moon and how that moved. It could be Venus or Jupiter.
To help you identify the object, you could install Stellarium, an open source planetarium.
You could also try to record the azimuth with a compass as well as the exact time.
A compact camera with a good zoom should be able to show the phase of Venus. If it looks like a very small waxing moon, it is Venus. If it's a full disk, it's probably Jupiter. These guidelines are only valid now, and will change over time. Stellarium will help.
The following is multiple choice question (with options) to answer.
This white object is visible due to being close to earth | [
"Venus",
"Mars",
"Neptune",
"our Moon"
] | D | the moon is the celestial object that is closest to the Earth |
OpenBookQA | OpenBookQA-4350 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
What's used by migrating animals to find locations? | [
"global positioning system satellites",
"a sense of smell",
"our planet's magnetic patterns",
"the stars in the night sky"
] | C | Earth 's magnetic patterns are used for finding locations by animals that migrate |
OpenBookQA | OpenBookQA-4351 | 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.
A seismometer would be ineffective | [
"on dry land",
"on a star",
"on the coast",
"on a continent"
] | B | a seismometer is used to measure the strength or magnitude of an earthquake |
OpenBookQA | OpenBookQA-4352 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
A person stranded in the tundra is likely to | [
"overheat",
"feel warm",
"fly.",
"perish"
] | D | if a living thing becomes too cold then that living thing will die |
OpenBookQA | OpenBookQA-4353 | climate, seasons, ice-age, axial-obliquity
Image originally from The Petroleum System Blog
Using that formula, the temperature at the poles (reduced to sea level) would be -16.8 °C (from the figure actual data points it can be seen that in real life the south pole is much colder than the north pole).
Now, the previous assumptions contradicts the requirement of "equilibrium", because the above scenario is far from steady state.
So now I will go on to try to describe what would happen to Earth's climate in your hypothetical scenario:
One thing that we learned by studying how the Milankovitch cycles trigger and reverse Pleistocene ice ages, is that to initiate an ice age cold winters are not necessary, what is needed are cold or mild summers.
Currently, the inclination of Earth axis (a.k.a. obliquity) varies between 22° and 24.5° , with a mean period of 41,040 years. When the inclination is 22°, mild summers occur and, therefore, the perfect condition to initiate an ice age (specially when combined with other ad-hoc orbital conditions). The permanent equinox situation you propose, is equivalent to an obliquity of 0°, that would lead to the coldest possible summer (this is, no summer at all). Therefore, such condition would set the Earth on track for an intense and never-ending ice age.
Let me explain how this could work: Using the formula above, the temperatures would be permanently below zero between the poles and latitudes 58.3°. Therefore, snow would start to accumulate in those areas, building an ice sheet and once the ice sheet gets thick enough it would start flowing outwards.
Figure from Lumen Learning.
The ice sheet then becomes self-sustaining due to two positive feedbacks:
Due to its high albedo, it would reflect most of the solar radiation back to the space, cooling down the Earth.
As the ice sheet advance, its thickness adds to the elevation of the terrain, therefore the surface is higher and colder, allowing snowfall beyond the 58.3° of latitude. The thicker it grows the more it can advance towards the equator.
The following is multiple choice question (with options) to answer.
Which likely would suffer in the arctic? | [
"a polar bear",
"a lion",
"a penguin",
"a walrus"
] | B | if a living thing becomes too cold then that living thing will die |
OpenBookQA | OpenBookQA-4354 | thermodynamics, temperature, estimation, fusion, explosions
I'll keep this around for the next time I need to scare someone into checking their sources ─ it's a monument to academic carelessness, if you will ─ because it's such a good example of how things fall apart if you don't look carefully enough. The claim, in its original context, is roughly reasonable - but the Vsauce claim falls flat under even mild scrutiny.
The following is multiple choice question (with options) to answer.
To destroy embarrassing evidence you can | [
"clobber it with a whale",
"post it on a social network",
"discard it in a rubbish bin",
"flick it into lava"
] | D | high temperatures can cause an object to combust |
OpenBookQA | OpenBookQA-4355 | java, role-playing-game
//This is where the critter attack goes
/*
* d100();
*
* if (d100Result >= 0 && d100Result <= 20) {
*
* } else if (d100Result >= 21 && d100Result <= 40) {
*
* } else if (d100Result >= 41 && d100Result <= 100) {
*
* } else {
* System.out.println(there is an error here!");
* }
*
*/
d3();
switch (d3Result) {
case 1:
critterOffensive = true;
critterDefensive = false;
critterEvasive = false;
System.out.println("The " + critterName + " charges!");
System.out.println("Your children and the " + critterName + " are evenly matched!");
break;
case 2:
critterDefensive = true;
critterOffensive = false;
critterEvasive = false;
System.out.println("The " + critterName + " protects itself!");
System.out.println("Your children crush the " + critterName + "'s defenses!");
System.out.println("The " + critterName + " takes damage!");
critterHealth -= 1 * missionWorkerDrones + (missionWarriorDrones * 2);
break;
case 3:
critterEvasive = true;
critterDefensive = false;
critterOffensive = false;
System.out.println("The " + critterName + " moves quickly!");
System.out.println("Your children are outflanked by the " + critterName + "!");
System.out.println("One of your drones falls from it's wounds!");
d2();
switch (d2Result) {
case 1:
if (missionWarriorDrones > 0) {
killWarrior();
} else if (missionWarriorDrones <= 0) {
killWorker();
}
break;
case 2:
The following is multiple choice question (with options) to answer.
A gila monster will likely have to interact negatively with | [
"trees",
"eagles",
"snails",
"sharks"
] | B | hawks eat lizards |
OpenBookQA | OpenBookQA-4356 | machine-learning, correlation
Title: How do I determine which variables/features have the strongest relationship with each other? This is my problem:
I have 10 variables that I intend to evaluate two by two (in pairs). I want to know which variables have the strongest relationships with each other. And I'm only interested in evaluating relationships two by two. Well, one suggestion would be to calculate the pairwise correlation coefficient of these variables. And then list the pairs with the highest correlation coefficient to the lowest correlation. That way I would have a ranking between the most correlated to the lowest correlated pairs.
My question is: Is there anything analogous in the world of artificial intelligence to the correlation coefficient calculation? That is, what tools can the world of AI / Machine Learning offer me to extract this kind of information? So that in the end I can have something like a ranking among the most "correlated" pairs from the point of view of AI / Machine Learning?
In other words, how do I know which variable among these 10 best "relates" (or "correlates") with variable 7, for example? It sounds like you have a series of data points, each with 10 related measurements, and you want automatically assess which of the measurements are most closely related to each other.
You are right that the correlation coefficient is a good choice for this.
Other techniques used in some AI algorithms include the Information Gain measurement (where you measure the reduction in entropy of one variable that follows from partitioning on another one), and embedded feature selection approaches, like the one in this paper.
The following is multiple choice question (with options) to answer.
Which relationship is most true? | [
"hawks EAT lizards EAT beetles EAT grass",
"hawks EAT bears EAT beetles EAT dogs",
"hawks EAT cats EAT beetles EAT air",
"bears EAT lizards EAT horses EAT grass"
] | A | hawks eat lizards |
OpenBookQA | OpenBookQA-4357 | biochemistry, bacteriology, food, toxicology
The Food and Nutrition Board of the U.S. Institute of Medicine indicates that Tolerable Upper Intake Levels (known as ULs) for iron is 45 mg/day. [Source].
Note: Tolerable upper intake level (UL) is the highest level of daily nutrient consumption that is considered to be safe for, and cause no side effects in, 97.5% of healthy individuals in each life-stage and sex group.
The World Health Organization (2003) suggests:
The average lethal dose of iron is 200–250 mg/kg of body weight, but death has occurred following the ingestion of doses as low as 40 mg/kg of body weight
Of course, one can get iron poisoning due to an acute overload of Fe.
Toxic effects begin to occur at doses above 10–20 mg/kg of elemental iron.
Ingestions of more than 50 mg/kg of elemental iron are associated with severe toxicity
See Abhilash et al. (2013) for an example study examining fatail Fe overdoe in adults.
Note: inhalation of Iron Oxide dusts is complicated but potentially dangerous, but should be of no concern to you.
However, outside of trying to OD on iron supplements, it's not easy to consume that much iron. So even given all tose nasty numbers, I wouldn't be too concerned
According to 2 citations (Greentree & Hall 1995 and Goyer 1996) in The toxicity of iron, an essential element:
Because iron must be ionized to be absorbed, metallic iron and iron oxide (rust) are not generally of concern when they are ingested.
Even when iron is heated (and supposedly ionized) very little becomes available for ingestion:
This source cites a 1986 study that found that cooking in a cast iron skillet added typically 1-4 mg (though as high as 7 mg) of iron into the food (well below dangerous levels)
Besides, iron oxide is already present in most drinking water.
Concentrations of iron in drinking-water are normally less than 0.3 mg/L [source] and is seldom found at concentrations greater than 10 mg/L or 10 ppm [source].
Bacteria connection:
There are bacteria associated with rust:
Iron-oxidizing bacteria are chemotrophic bacteria that derive the energy by oxidizing dissolved ferrous iron
The following is multiple choice question (with options) to answer.
Much iron is in | [
"Earth's second layer",
"cups of coffee",
"the sky",
"empty"
] | A | the mantle is located just below Earth 's crust |
OpenBookQA | OpenBookQA-4358 | pressure, everyday-life, physical-chemistry, vacuum
Extra: Is this (your answer) also a reason for not semi-compressing half-full flexible plastic cola bottles before closing them? Creating a vacuum above carbonated drinks causes the CO2 to outgas faster--simply because there is no CO2 above the drink to diffuse back into the liquid. In physical terms this means there is no vapor pressure of CO2 above the liquid, so net movement of CO2 is from the drink to the space above it. If you leave a closed carbonated drink bottle long enough, the partial pressure of CO2 in the drink and in the space above the drink are the same--rate of gas that escapes the drink is equal to the rate that dissolves back into it--equilibrium.
Note that it is not solely about gas pressure but partial pressure of the gas you are interested in. Pressurising your champagne bottle with pure air to above atmospheric and sealing it wont extend the bubblyness. You need to pressurise with CO2 gas. For soft drinks you need 2 bar CO2 (in a typical coke bottle left alone for awhile, the space above the drink is almost pure CO2 and is at 2bar).
Your question about PET bottles is a good one. As mentioned, without a CO2 pump you cant extend the life of your sodas. Squeezing a half full bottle and sealing it removes the volume of available space above the drink, so when CO2 inevitably escapes the liquid to form equilibrium vapor pressure above it, less CO2 is required for this to happen--if the bottle doesnt expand back. The problem is that the bottle has structurual integrity and is designed to spring back. This creates low pressure in the bottle, causing CO2 to outgas faster than if you hadn't done all this in the first place. The upside is that equilibrium is the same--you lose the same amount of CO2 from the drink as if you had not done this. To really save gas, when you squeeze the bottle and seal it, you have to find a way to keep the bottle from springing back. Or just store unfinished soda in bottles where there is very little space for CO2 to outgas into.
The following is multiple choice question (with options) to answer.
Drinking cola daily removes layers from the surface of | [
"enamel on molars",
"spoons",
"porcelain",
"the coffee pot"
] | A | An example of a chemical change is acid breaking down substances |
OpenBookQA | OpenBookQA-4359 | measurements, metrology, time
Title: How is a second measured? And why is it measured that way? The earth's rotation around itself (one rotation around Earth's own axis) doesn't take exactly 24 hours. It off by some seconds which becomes somewhere around 6 hours per year and 1 day in 4 years(leap year), which brings the question why didn't we modify the measurement of 1 second ever so slightly so as to avoid leap years altogether.
Well how is 1 second measured exactly? Wikipedia says
the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. [1]
Well, why is it measured that way? Is there any technical reason like it is easy to measure and can be standardized easily? Or is it really possible to modify the measurement of time?
why didn't we modify the measurement of 1 second ever so slightly so as to avoid leap years altogether.
The rotation of earth and the revolution of earth around the sun is not at all synchronized. The Earth really rotates 365.24219647 times during each revolution (in 1992, this ratio changes slightly every year, the tropical year gets roughly a half second shorter each century); so even if we fixed the definition of time to the revolution of earth around sun, we will still need a leap year every 4 years (what we wouldn't need would be leap seconds).
Another reason is because precise time measurement would become incomparable. Since the period of revolution of earth (i.e. the tropical year) isn't constant, if we used the definition of second to exactly match the period of revolution, then whenever you want to specify a precise duration of time, you'll also have to specify which year that definition of second is taken from, and you'll need a table that records the length of second of each year.
Is there any technical reason ... ?
Yes, because with the proper equipment anyone, anytime can take a caesium-133 atom, put it under the specified condition and measure the same second, and it won't have yearly change like the second from earth rotation/revolution would. As far as we know, the frequency of caesium-133 in the 1978 should be the same as the frequency of another caesium-133 in 2049.
The following is multiple choice question (with options) to answer.
Seconds are used to measure | [
"height",
"passing of time",
"time of day",
"seconds of food"
] | B | seconds are used to measure time |
OpenBookQA | OpenBookQA-4360 | atmosphere, atmospheric-chemistry, evaporation
Title: Does evaporated hand sanitizer pollute the environment? With all the COVID-19 stuff going on, I feel the usage of alcohol-based hand sanitizers has increased many fold.
I wonder what happens to all that evaporated alcohol in the atmosphere.
How soon does alcohol react in environment and what other substances are formed? Assuming you are talking about ethanol: it is a common chemical substance, generated naturally from e.g. rotting fruits. So any pollution from hand sanitizers should be negligible.
What happens to the alcohol in the atmosphere is an interesting sequence of reactions. I took the info below from an article (see link below).
In the air, ethanol is oxidized quickly (half-life is a few days) into acetaldehyde $CH_3CHO$, which is further oxidized into other compounds, most of which are harmless. However, if the air contains nitrogen dioxide $NO_2$, it can form peroxyacetyl nitrate $CH_3C(O)OONO_2$, which is dangerous.
Source
The following is multiple choice question (with options) to answer.
As Ethanol burns it expels what into the ozone | [
"radiation",
"lightning",
"CO2",
"nitrogen"
] | C | biofuel releases carbon dioxide into the atmosphere |
OpenBookQA | OpenBookQA-4361 | organs, lifespan
Title: Organs lifespan out of the body What organ can be conserved outside of the body for the longest time and still function when reimplanted? Depends what you consider an organ. Typically though it's the cells which require the most metabolic activity which have the shortest life span. The kidney is the most of the major internal organs with up to 36 hours with liver coming second at up to 16 hours.
The following is multiple choice question (with options) to answer.
When a human's organs stop working and he stops breathing, that person | [
"goes to Mcdonalds",
"perished",
"dances",
"plays"
] | B | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-4362 | evolution, mammals, marine-biology
The question remains: why? The most likely explanation is that cetaceans evolved to exploit an unfilled ecological niche or adapted to new niches that formed as a result of plate tectonics or other types of environmental changes that occurred 50-55 million years ago. The niche describes all of the living and non-living resources needed by an organism to survive. Although land-based mammals were increasing in diversity, few or none were present in the oceans. The basic hypothesis is that the early whale-like artiodactyls, like Indohyus and Pakicetus were land-based (terrestrial) mammals that spent most of their time near the water's edge. Over time, they adapted to the niches in the ocean. Fossils like Ambulcetus and Rodhocetus showed clear evidence of swimming ability, with flattened tails and the enlarged rear feet. In addition, the nostrils shifted from the front of the face to the top of the head, which we recognize as the blowhole.
The shift to the aquatic habitat allowed these species to exploit resources that were not available to land-based mammals, thereby reducing competition for the resources. Reduced competition allows more individuals to survive and reproduce.
Similar scenarios are very likely for other marine mammals, such as seals or manatees. They evolved to take advantage of ecological niches that were not filled by other organisms. This basic concept, evolving to fill available niches, is a common outcome of the evolutionary process.
The of adaptation of cetaceans and other mammals to the oceans may be similar to that of the hippopotamus. Hippos spend most of their time in the water, and they show many adaptations that allow them to live in the aquatic environment. The eyes and nostrils of the hippo are high on the head, which allows them to remain almost entirely submerged but still see and smell, as shown below.
(Hippo photo by Johannes Lunberg, Flickr Creative Commons.)
Hippos feed underwaters, they are heavy enough to walk on the bottom of the river, and the mate and give birth underwater. The young can suckle underwater. Clearly, hippos seem to be another mammal that is "returning to water." Similar types of processes must have occurred in cetaceans for them to adapt to the marine habitat.
The following is multiple choice question (with options) to answer.
When the Platypus emerges and new life into the pouch it has been | [
"died",
"birthed",
"flown",
"ran"
] | B | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-4363 | telescope, earth, optics
If $S$ is the distance to the satellite then the angular size is
$$\frac{h_i}{S} \approx \frac{h_o}{d_o}\frac{f}{S} = \frac{h_o}{d_o}\frac{r}{2S} \approx \frac{1.4\times10^6}{150\times10^6}\frac{6.4\times10^3}{2\times 1.6\times 10^6}\approx 1.8 \times 10^{-5}$$
where distances are in km. (We have also ignored that the image is $\frac{R}{2}$ closer to the satellite than is the Earth's center.)
On a more descriptive note, the reflection on perfectly smooth water would look like a very bright spot about 29 km in diameter. It is blurred out (due to sea waves) to about ten times that diameter on the image. It would be interesting to calculate the brightness (per area) of the (unblurred) spot compared to the brightness of the sunlit Earth's surface.
The following is multiple choice question (with options) to answer.
The topography of our only natural satellite's surface is | [
"smooth",
"made of cheese",
"full of gold",
"mountainous"
] | D | the moon 's surface contains highlands |
OpenBookQA | OpenBookQA-4364 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
A thing which is a producer in the food chain is most likely to be a | [
"squid",
"clover",
"mouse",
"hawk"
] | B | producer is a kind of role in the food chain process |
OpenBookQA | OpenBookQA-4365 | zoology, ethology, behaviour, psychology, death
I can't prove it to you, but I know that my Beagle had a rich emotional life. I know this because I spent huge amounts of time with him. He was a close friend of mine. I would just as soon question whether my wife has real emotions as my dog. I can't prove that my wife's emotions are real either, but I don't have to. It would be silly to assume that everything she shares with me is some sort of evolutionary programming, and not real emotion. Now, when I extend this to cetaceans, I must admit that I don't have any friends in those circles. So I can only guess.
The following is multiple choice question (with options) to answer.
Jerry noticed that his dog was leaving a lot more fur on his couch than he did a month earlier. That might be because | [
"the seasons are changing from fall to winter",
"the dog is a hairless breed",
"the seasons are changing from winter to spring",
"the moon is full"
] | C | some animals shed fur in warm weather |
OpenBookQA | OpenBookQA-4366 | thermodynamics, thermal-radiation, thermal-conductivity
Title: What can I do to be invisible for the IR-camera on board of a police helicopter? I think we all have seen the images of crime suspects, running in the dark of the night to escape the police, made with the help of infrared cameras. What can I do to be invisible to these cameras when I run from a bank I just robbed, through gardens, jumping over fences, but not running through long tunnels, or through woods with densely packed trees? When I run without having done anything (except robbing the bank) I show up on the screens connected to these cameras as a highlighted "blob" looking remotely human.
Should I wear a suit filled with ice, enclosing my entire body? Or would that also be visible, because in that case, I can imagine you see a dark human blob on the screen because the temperature of that suit is lower than my surroundings (unless it's a cold winter night, but let's assume it's a normal summer night or winter night if I lived on the southern hemisphere).
Should I wear a suit with excellent heat-isolation enclosing my body and which I've prepared in such a way that it has the same temperature as the air that night?
Keeping something (a big heat-isolating plate) above my head seems unpractical to me, and some parts of my body will certainly show up on the screen helicopter with the cops in it.
What else can I do to be invisible while still being able to run freely?
By the way, I'm not planning anything... Military gear is typically pretty good at trumping police gear. BAE systems recently came out with an adaptive camouflage system that can make a tank's IR signature look like anything they please
The next best approach is probably confusion. There's a long history of using Craigslist to put a "want ad" for people dressed exactly like you, then you rob a bank and the police don't know who to go after.
Failing that, an IR camera picks up heat, so anything highly insulative will be effective. My recommendation is something fuzzy, or made of foam. The fuzzy things tend to stay very close to room temperature
What could possibly go wrong.
The following is multiple choice question (with options) to answer.
In May I have a black cat what might I be unable to wear? | [
"dark purple",
"yellow",
"dark grey",
"black"
] | B | some animals shed fur in warm weather |
OpenBookQA | OpenBookQA-4367 | climate-change, glaciology, ice-sheets
Title: Can ice caps reform if they disappear? Excuse my ignorance. I'm under the impression that there are various types of ice at the poles, but I don't know the difference or the significance of each type, so, in terms of whatever is actually melting in these areas as a result of climate change, is it possible that it could come back if greenhouse gas emissions were eliminated or something like that? Basically, I'm assuming that the ice caps are necessary in order to maintain the habitability of the planet for humans, so is there some sort of threshold of melting that would essentially count as a point of no return or is there always the possibility of seeing the ice caps return to safe levels? Yes, polar ice can melt -- significantly, if not completely, with substantial effects on human civilization. And it can stabilize and recover, but the question is at what pace relative to human civilization.
There are generally three types of polar ice:
Ice sheets: "An ice sheet is a mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). The two ice sheets on Earth today cover most of Greenland and Antarctica."
Ice shelves: "Permanent floating sheets of ice that connect to a landmass."
Sea ice: "Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land."
Sea ice is usually 1-2 meters thick; shelf ice is 100-200 meters thick; sheet ice is one to several kilometers thick.
The poles differ significantly. It's often pointed out that the Arctic is an ocean surrounded by land and the Antarctic is land surrounded by ocean. The North Pole is occupied by sea ice, about half of which melts every summer and reforms every winter.
At the other extreme are the ice "caps," more or less the ice sheets in Greenland and Antarctica that extrude ice in the form of glaciers and ice shelves that continuously flow into the ocean, breaking apart and melting.
To take just Greenland: Greenland has had some degree of glaciation for ~38 million years, but lost much or almost all of its ice during a warming period about 400,000 years ago, suggesting that the current ice sheet was created in that time.
The following is multiple choice question (with options) to answer.
Ice melting erodes | [
"clouds",
"plants",
"granite",
"rivers"
] | C | water causes the most soil and rock erosion |
OpenBookQA | OpenBookQA-4368 | optics, visible-light
Title: Why is blue the last colour to disappear underwater? I have been told for years about how red is the first colour to "disappear", or apparently become unobservable, when diving to a significant depth beneath water.
When I recently did some diving myself, I noticed this vividly, seeing the blood of my nails and hand become apparently blue... Why does this occur? (I understand that this is a scattering effect but would appreciate a more in-depth explanation, e.g. whether this could happen in air...)
On a similar note, my father recently pointed out to me that during sunsets, blue flowers become seemingly more vivid in their colours - I assume that this is a similar scattering effect (related to Rayleigh scattering?), but what is it? The reason is that red light is more readily absorbed by water than blue light (by orders of magnitude). The physical reason for the absorption is molecular transitions - in particular overtones of vibrational bands. It has nothing to do with Rayleigh scattering, which is more effective at shorter wavelengths, but is quite negligible here.
Since there are fewer red photons when you are below a depth of water, then everything will appear bluer than it does above the water.
Some more details about the water absorption spectrum can be found here.
The following is multiple choice question (with options) to answer.
Why would something appear blue? | [
"it reflects the same wavelength as fire",
"it reflects the same wavelength as coal",
"it reflects the same wavelength as the sun",
"it reflects the same wavelength as the sea"
] | D | if an object is blue then that object reflects only blue light |
OpenBookQA | OpenBookQA-4369 | homework-and-exercises, forces
Title: Newton's third law confusions According to Newton's third law of motion, if body A exerts a force on body B, then body B exerts a force on body A that is equal in size but opposite in direction, then how do things move? Bodies move because there are two equal and opposite forces on two different bodies, not on the same one.
The following is multiple choice question (with options) to answer.
if two equal forces in opposite directions act on an object then that object will stay where? | [
"360 degrees apart",
"opposite",
"split",
"between them"
] | D | if two equal forces in opposite directions act on an object then that object will stay in the same place |
OpenBookQA | OpenBookQA-4370 | homework-and-exercises, kinematics, reference-frames, projectile, drag
Publicly available solution states that
What does $t_{air}$ represent? Why is it different from $t$? If the ball's lateral displacement isn't proportional to time, then why isn't $u$ something like $u_{air}$? Also how is the displacement of the moving(which is that?) frame $s$?
P.S. I've also seen the solution video on YouTube that states that the balls trajectory in the wind's reference frame is a straight line? How? This problem nicely teaches the solver the importance of choosing a situation-appropriate coordinate system. Indeed, when looked at from the right perspective, the situation at hand turns into a simple problem of kinematics and does not require any complicated modelling of the ball's drag.
The key insight is that in the air's rest frame, the drag force is always directed opposite to the ball's instantaneous velocity vector. Since the only other force acting on the ball, gravity, merely changes the vertical component of the velocity vector, we can observe that there is no force that could change the velocity vector's horizontal orientation: in the rest frame of the air, the ball's trajectory is a straight line when viewed from above and is parallel to the initial velocity vector. Viewed from the side, we would see an air-restistance-modified parabola but we purposefully look away from this complication.
Let's choose the air rest frame coordinate system such that the footballer is at the origin at $t=0$, and the initial velocity has the components $\boldsymbol v_0= v\cos \alpha\ \boldsymbol{e}_x - u\ \boldsymbol{e}_y + v\sin\alpha\ \boldsymbol{e}_z$, where $\alpha = \arccos 0.8$, $v=25\,\mathrm{m}/\mathrm{s}$ the initial ball speed, and $u=10\,\mathrm{m}/\mathrm{s}$ the wind speed. As the initial velocity and the ball's trajectory are parallel (when viewed from above), the following two triangles are similar,
The following is multiple choice question (with options) to answer.
Air is blowing a ball equally from east and west, the ball will do what? | [
"Move east",
"Move west",
"Move north",
"Move nowhere"
] | D | if two equal forces in opposite directions act on an object then that object will stay in the same place |
OpenBookQA | OpenBookQA-4371 | photosynthesis, botany
Title: Photosynthesis - Light Intensity Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis? The rate of photosynthesis varies from plant to plant. Some plants require more light and some require less. If you move light closer to the plant, in most scenarios the rate of photosynthesis is likely to be increased. For some plants a minimal light is enough for their photosynthesis, so for those plants, moving light source closer or further will have less effect.
The following is multiple choice question (with options) to answer.
Which of the following items can perform photosynthesis? | [
"a flying wasp",
"a speedy cheetah",
"wet dirt",
"a yellow tulip"
] | D | plant cells can perform photosynthesis |
OpenBookQA | OpenBookQA-4372 | biochemistry, botany, plant-physiology, photosynthesis
What are typical characteristics of different plants in this regard? I.e., how do common species of plants manage their C consumption before (and after) the development of leaves? There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which store energy in their bonds. That energy is then released when required to power other reactions, which is how a plant lives and grows. C is also incorporated into all the organic molecules in the plant.
Plants require several things to live: CO2, light, water and minerals. If any of those things is missing for a sustained period, growth will suffer. Most molecules in a plant require some carbon, which comes originally from CO2, and also an assortment of other elements which come from the mineral nutrients in the soil. So the plant is completely reliant on minerals.
Most plants, before a leaf is established or roots develop, grow using energy and nutrients stored in the endosperm and cotyledons of the seed. I whipped up a rough diagram below. Cotyledons are primitive leaves inside the seed. The endosperm is a starchy tissue used only for storage of nutrients and energy. The radicle is the juvenile root. The embryo is the baby plant.
The following is multiple choice question (with options) to answer.
The cell of a plant when photosynthesizing may most require | [
"access to roofless space",
"a complete vacuum in space",
"a room with blackened windows",
"dark basement living quarters"
] | A | plant cells can perform photosynthesis |
OpenBookQA | OpenBookQA-4373 | newtonian-mechanics, forces, energy-conservation, work, free-body-diagram
Title: Pulling yourself upward with a pulley — How is this consistent with energy conservation? Suppose you are in a cage suspended by a massless rope that goes around an ideal frictionless pulley. You are supposed to pull yourself up using the rope. You and your cage together are of mass $m$. Let's say you are pulling yourself up at a constant velocity, so the acceleration is zero. We can solve for the force $T$ you have to apply to the rope.
The following is multiple choice question (with options) to answer.
A pulley is used to lift what on a flagpole? | [
"shirts",
"red cards",
"national symbols",
"underwear"
] | C | a pulley is used to lift a flag on a flagpole |
OpenBookQA | OpenBookQA-4374 | explosions
Title: What will happen to you if you're standing near exploding TNT bomb near 20meter away in Vaccum? What I think here could be ,that we'll feel less powerful shock wave as there is no medium of air through which gases can travel . If their is any other possibilities than please suggest ! You'll want to add some numbers to your question if you want someone else to do some calculations.
For a simple answer:
In a vacuum
Sound does not travel so you wouldn't suffer overpressure damage to the same extent, though depending on the size of the explosion it could fill the vacuum and increase the pressure enough to kill or injure you.
Any shrapnel will travel faster in a vacuum, doing more damage.
" ... Outer space explosions tend to manifest a spherical 'cloud', reminiscent of other space-based explosions ...".
Underwater (opposite situation)
Sound travels far, and pressure a short distance, resulting in a bubble pulse.
Shrapnel won't travel very far.
Direct contact of an exploding device enhances the explosion because the pressure of the water helps direct the explosion towards the most forgiving direction (you, or a sub).
In your case the combination of air and vacuum is closer to the 'all vacuum' example rather than the opposite 'underwater' example. It depends upon what numbers we are talking about whether 20 meters makes a difference, as does the extent of the vacuum and composition of the container.
A huge explosion will create plenty of vacuum. Small explosions are used to protect against explosions in the Iron Curtain or explosive reactive armor methods of tank protection.
The following is multiple choice question (with options) to answer.
Explosions can cause harm to what? | [
"clouds",
"radio waves",
"ground crawlers",
"airflow"
] | C | explosions can cause harm to an organism |
OpenBookQA | OpenBookQA-4375 | bacteriology, food, hematology, toxicology, parasitology
Title: Blood consumption Is consumption of blood more "dangerous" compared to meat?
There was a news-article about unnatural chemicals found in the blood of mothers. This reminded me about a question I have pondered upon from time to time. Now, I am not a vampire, but curious as to the nature of blood vs meat in animals. More specifically unhealthy components.
There are various examples of viruses being in danger of spreading by consumption of raw blood like ebola, H5N1 etc. (But then also meat etc.)
Perhaps easier if I throw out some questions to show what I am asking:
Are there more of such in blood then meat?
Are there other things that can be worse in blood even after preparing? Like cooking, conservation etc.
Are parasites etc. more frequently found in blood?
Are there organisms that are highly resilient to heat treatment found in blood?
Are there more heavy metals in blood then meat? (Which I assume cooking does not give much of a difference.)
Other toxins?
Some references:
http://www.eufic.org/article/en/food-safety-quality/animal-health/expid/review-animal-diseases/
http://www.fao.org/avianflu/en/qanda.html
Is consumption of blood more "dangerous" compared to meat?
Actually yes, a simple high dose of blood is enough to kill. The cause is, though it is most important thing to live when flowing the vessel, it's highly toxic when consumed. There are high chances of getting haemochromatosis or Iron overload.
Source and More on this:
http://www.livescience.com/15899-drinking-blood-safe.html
Composition of Blood
(source: snmjournals.org)
The following is multiple choice question (with options) to answer.
Which is likeliest to harm an organism? | [
"cookies",
"drinking",
"eating",
"a car explosion"
] | D | explosions can cause harm to an organism |
OpenBookQA | OpenBookQA-4376 | the-moon, night-sky
And another useful reference at planetarium.madison.k12.wi.us:
At the beginning of Winter, when it's nighttime all of the time, the moon would be in the sky for the 2 weeks closest to Full Moon, and then below the horizon for the next 2 weeks. And at the beginning of Spring (click on the graphic), when the sun is at sunrise all of the time, the moon would be up in the sky for the 2 weeks closest to First Quarter (waxing), and then below the horizon for the next 2 weeks.
The animated graphic above shows what we would see from the North Pole if we went out every day at noon, for 14 days in a row, from March 1st to March 14, 2006. We start with a thin crescent moon near the horizon, and end with a full moon near the horizon. Halfway through, the First Quarter moon would be when the moon is highest above the horizon.
Keep in mind, that if you were observing the moon constantly, throughout a 24 hour period, the moon would seem to move to the right in the sky along with the sun, stars, and planets due to the Earth's rotation. Nothing would seem to rise and set: they would just seem to circle around you.
The following is multiple choice question (with options) to answer.
If you missed the rising moon today you will have to wait till when to see it again | [
"30 years",
"10 months",
"10 minutes",
"24 hours"
] | D | the moon rising occurs once per day |
OpenBookQA | OpenBookQA-4377 | 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.
All the plants in an area have died from a fire. Why would carnivores like foxes be less abundant as a result? | [
"the wolves left the area",
"the foxes were bored without any live trees to climb",
"the foxes normally eat only plants",
"the rabbits and mice in the area needed the plants"
] | D | as the supply of food in an environment decreases , the population of animals in that environment will decrease |
OpenBookQA | OpenBookQA-4378 | c#, performance, programming-challenge, dynamic-programming
//the amount of water is the minimal between left and right height.
// and we need to remove the height of the cell, think of this
// like where the ground starts
for (int i = 1; i < size - 1; i++)
{
ans += Math.Min(leftMax[i], rightMax[i]) - height[i];
}
return ans;
}
} There is no reason to use lists instead of arrays, new int[size] will give you an array full of 0s without any overhead.
You can get away with creating only one array (leftMax) and then while computing the values of rightMax, instead of saving them into an array, complete the full calculation of how much to add to ans. Like this:
public int TrapDynamicProgramming(int[] height)
{
if (height == null || height.Length == 0)
{
return 0;
}
int ans = 0;
int size = height.Length;
int[] leftMax = new int[size];
leftMax[0] = height[0];
for (int i = 1; i < size; i++)
{
leftMax[i] = Math.Max(height[i], leftMax[i - 1]);
}
int rightMax = height[size - 1];
for (int i = size - 2; i >= 0; i--)
{
rightMax = Math.Max(height[i], rightMax);
ans += Math.Min(leftMax[i], rightMax) - height[i];
}
return ans;
}
The following is multiple choice question (with options) to answer.
Which only needs sparse water? | [
"fish",
"frogs",
"whales",
"chuckwallas"
] | D | some lizards live in desert habitats |
OpenBookQA | OpenBookQA-4379 | rainfall, tropical-cyclone
Title: How can a storm drop 40 inches (1 metre) of rain? Hurricane Harvey dumped more that 20 inches (500 mm) of rain over a large region, with 40+ (>1000 mm) in some spots... and much more expected.
How is that possible?
Does the atmosphere really hold that much water?
Or is it getting repeatedly evaporated from the ocean and dropped onto the land by the circular winds, implying an enormous evaporation rate while over water? You were right to question whether the atmosphere really held that much water. It comes nowhere close! We use precipitable water to track this, which is the measure of all moisture in the entire column of air in the troposphere. We can get good widespread estimates from remote observations. This animation shows current amounts of precipitable water levels across the US from satellite. Here is a still from this afternoon (Sunday, August 27) during the Harvey event:
75 mm is less than 3 inches.
We also get in-situ exact measurements worldwide from twice daily radiosonde balloon launches. Unfortunately none are located right near the locations receiving excess rainfall. But you can check US sites of current precipitable water measurements any time by going to SPC's sounding page and looking for the PW value in the left side of the bottom table. SPC also maintains a climatology page for precipitable water and other values. You can see there that 3 inches (76 mm) of moisture in the sounding is extremely rare, and no US site has ever had 4 inches (102 mm) of precipitable water.
However, the answer is also not truly found in evaporation rates. The conditions in strong hurricanes do greatly enhance evaporation rates due to the high wind speeds and warmer waters. Measurements are actually a bit difficult to come by in such extreme conditions, with challenges in isolating evaporation effects from spray as well as in getting the instruments positioned into such environments (new field campaign: who wants to take the research ship out into the category 5 hurricane!?!). As this 2007 study by Trenberth et al. noted:
We are unaware of reliable estimates of evaporation in hurricanes, and published measurements do not exist in winds above about 20 m s−1 although some progress has been made in the Coupled Boundary Layer Air-Sea Transfer Experiment (CBLAST)
The following is multiple choice question (with options) to answer.
A storm moving over the earth will dump more rain on a | [
"meadow",
"sandy area",
"arctic",
"desert"
] | A | some lizards live in desert habitats |
OpenBookQA | OpenBookQA-4380 | ocean, paleoclimatology, rivers
Title: How has river to ocean flux changed over the last 500 million years? Do we have any rough indices of how this flux has changed? I'm particularly interested in knowing whether the flux was higher or lower during the time of Pangaea, or during the time of the unusually warm Eocene (or at least up to the earliest time that this flux can been measured from). There is no direct answer. One way to think about this is to consider the water cycle. Water evaporates from the oceans and is precipitates over land. Distance from the ocean affects the amount of precipitation so at the center of a large contintent you may have less precipitation than over a smaller one. Mountains also drain moisture out of the air as it is heaved. hence the topography of the continents affect this effect. A Pangea directly after collisions will likely have more and higher mountains than a later stage when break-up is imminent. Location on the earth's surface is a third factor since we have larger scale circulation belts that affect the atmospheric conditions so that we have a tropical belt (the Intertropical Convergence Zone) around the equator, a drier zone north and south of the ITCZ, followed by temperate and polar zones towards the poles. Hence the location of the continent(s) and their topography will affect the zones and the zones will will determine which parts receive more or less precipitation. Furthermore the movement of the continent(s) through these climate zones change conditions as well.
In summary, we can be sure it is not constant over geological times. The only possible way to get some relative handle on the question would be to try to apply a global circulation model to past continent configurations, including topographical effects and see what comes out, being aware of all uncertainties and comparing with geological evidence.
The following is multiple choice question (with options) to answer.
What is the effect of erosion on a river? | [
"More Volume",
"unchanged",
"Dries up",
"Less Volume"
] | A | erosion causes a river to become deeper and wider |
OpenBookQA | OpenBookQA-4381 | thermodynamics, fluid-dynamics, pressure, water, climate-science
Title: Would pumping warm humid air through a pipeline up to the top of a mountain produce a lot of fresh water? I have been doing a lot of research on the Internet lately about desalination processes and desalination plants and this led me to studying mountain weather and the orographic effect or orographic lifting.
The thought then occurred to me about whether a lot of fresh water could be produced by creating an artificially-produced orographic effect by pumping warm, humid coastal air through a pipeline that would lead to the top of a coastal mountain.
Orographic Effect:
I then made a conceptual drawing in MS Paint on how this could be done:
The temperature of the metal pipe will decrease as it ascends up the coastal mountain and this colder metal should cause the water vapor within the pumped air to condense on the inner wall of the pipeline forming water droplets. These water droplets will then be pulled down by gravity and should fall into a pipe leading to a water storage tank.
In the case that one air pumping plant cannot produce enough air pressure to push the air all the way up a mountain, then perhaps another air pumping plant would need to be stationed at the top of the mountain to assist with transporting the air upwards through the pipeline.
These air pumping plants would need to have a large volume industrial centrifugal blower fan like the ones built by Elektror Airsystems pictured here:
The following is multiple choice question (with options) to answer.
Erosion can make a source of H2O | [
"stay exactly the same",
"remain static over time",
"calibrate from its previous capacity",
"begin hosting underwater birds"
] | C | erosion causes a river to become deeper and wider |
OpenBookQA | OpenBookQA-4382 | geophysics, climate-change, glaciology
As we can see from the chart, there's been a pretty steady drop in CO2 PPM over the last 15 million years or so. As the ocean grows colder it can store more CO2 so there may be a correlation between falling temperature and falling CO2 PPM - one of the primary climate feedback mechanisms, but predicting future CO2 levels - I wouldn't even know what to guess. Certainly low enough CO2 PPM could lead to further ice ages, even after Antarctica drifts off the south pole, so, there's the problem - too many unknowns. This question has no answer.
A 4th possible key driver would be ocean currents, as indicated by the theory that the formation of the Isthmus of Panama may have been a key driver in the current ice age cycle, but predicting ocean current changes millions of years into the future is above my pay grade.
The 3 primary drivers do seem to fit past ice ages.
The the Andean-Saharan ice age period 425-450 million years ago, CO2 levels were much higher but that long ago the sun was perhaps 3%-4% less luminous and much of the land was over the antarctic circle.
The Karoo ice age period is associated with a drop in CO2 and an increase in O2 (Source)
That probably long and rambling and needs more than a little clean-up and I invite counterpoints, but I think that's the gist of estimating when ice ages will end. A precise answer isn't possible.
The following is multiple choice question (with options) to answer.
With the decrease in size of Antarctica Fiji will soon be | [
"gone",
"better for fishing",
"richer",
"colder"
] | A | as the level of water rises , the amount of available land will decrease |
OpenBookQA | OpenBookQA-4383 | glaciology, antarctic, sea-ice
Fan et al. (2014) (3) describe an earlier idea that the increase in greenhouse gases and ozone depletion may cause an increase in the increased westerly winds, there is considerable uncertainty in the interaction between these factors (4).
Models from Holland et al. (2014) (4) suggest a link between Antarctic-wide ice thickness and area trends contributing to overall sea ice trends.
Related to the models above, several papers suggest that the mechanism is related to increases in meltwater fluxes from the Antarctic continent itself (2)(3). The meltwater flux is modelled to have increased during the southern summer, depositing greater amounts of cool freshwater into the surface layers of the surrounding Southern Ocean, resulting in cooler SSTs in the southern summer, potentially causing the increase in summer sea ice extent trend.
However, most critically, Holland et al. (2014) (4) note that the freshwater 'extraction' by sea ice is a small percentage of the actual fresh meltwater flux. Instead they model that instead of freshwater flux, the driver is based on trends of Antarctic ice thickness and area.
This means that the increase in sea ice is not a 'counter balance' for the ice melted from the continental ice sheets, but rather, according to the models, the increasing sea ice extent appears to be a symptom of the continental ice sheet melting.
References
(1) Simmonds 2015 Comparing and contrasting the behaviour of Arctic and Antarctic
sea ice over the 35 year period 1979–2013 Annals of Glaciology
(2) Bitanja et al. 2015 The effect of increased fresh water from Antarctic ice shelves on
future trends in Antarctic sea ice Annals of Glaciology
(3) Fan et al. 2014 Recent Antarctic sea ice trends in the context
of Southern Ocean surface climate
variations since 1950 Geophysical Research Letters
(4) Holland et al. 2014 Modeled Trends in Antarctic Sea Ice Thickness, Journal of Climate (Full text here)
The following is multiple choice question (with options) to answer.
Which is the most likely factor for the amount of available ocean space increasing? | [
"glaciers cooling down vastly",
"glaciers getting much hotter",
"land space increasing tenfold",
"land shrinking over time due to cold"
] | B | as the level of water rises , the amount of available land will decrease |
OpenBookQA | OpenBookQA-4384 | Yes ;)
- 3 months, 3 weeks ago
That was easy.. $2^{16}$
- 3 months, 3 weeks ago
So, the question which I gave is of no use?
- 3 months, 3 weeks ago
The problem hasn't got a unique solution. A more interesting problem would be: How many solutions are there? But I think this is a very time expensive problem (at least if you don't want to program it).
- 3 months, 3 weeks ago
I don't know programming :(
- 3 months, 3 weeks ago
I think it's possible that I don't understand the question. (edit: Narrator: "He didn't understand the question.")
The lowest composite number I can generate with $2$ distinct factors is $2 \times 3 = 6 ( = 3! )$
The lowest composite number I can generate with $3$ distinct factors is $2 \times 3 \times 4 = 24 ( = 4! )$
...
The lowest composite number I can generate with $n$ distinct factors is $(n+1)!$
...
The lowest composite number I can generate with $28$ distinct factors is $29! = 8841761993739701954543616000000$. This has a lot more than 6 digits. What is it that I don't understand here?
(Additional, just for laughs, if I insist that the $28$ factors are prime factors, I get: $2566376117594999414479597815340071648394470$.)
- 3 months, 3 weeks ago
@Stef Smith, Sir, I did not understand what you mean. Please elaborate!
- 3 months, 3 weeks ago
A misunderstading of how factors work. Some days my brain doesn't work so well. :)
- 3 months, 3 weeks ago
Oh no problem then :)
- 3 months, 3 weeks ago
Hey Stef, The number 24 has more than 3 factors. It has 8 factors: 1, 2, 3, 4, 6, 8, 12, 24. Therefore, applying the factorial function does not work because 29! factorial has way more factors than 29.
I hope this helps :)
- 3 months, 3 weeks ago
Ah... I understand. Thanks.
The following is multiple choice question (with options) to answer.
A new what occurs once every 3 months? | [
"city",
"climatic term",
"hill",
"wave"
] | B | a new season occurs once per three months |
OpenBookQA | OpenBookQA-4385 | cell-biology, proteins, transcription, cell-signaling, intracellular-transport
Time is in minutes, and zeroed at first contact between the two cells. I've put a red dot on the T-cell and a blue one on the APC in the DIC images (left panes); hopefully that proves more informative than annoying. The right panes show GFP fluorescence and thus CD3 localization. As time progresses, CD3 is re-localized from one part of the membrane to another (the synapse). There is supposedly a video of this is in the supplementary information of the article, though I was unable to open it.
The rate and directionality of the movement implies that an active process is occurring, rather than simple diffusion. However, they did not find the actual mechanism for movement and I haven't found any follow-up papers in a brief search (though many subsequent papers implicate the cytoskeleton in this movement). Just to show that movement of transmembrane proteins can, in fact, be actively directed by the cytoskeleton, I refer you to this paper:
Grabham PW, Foley M, Umeojiako A, Goldberg DJ. 2000. Nerve growth factor stimulates coupling of beta1 integrin to distinct transport mechanisms in the filopodia of growth cones. J Cell Sci 113:3003-3012.
They show that membrane-spanning integrins are moved along actin filaments of the cytoskeleton by myosin motor proteins. Expectedly, the abstract does a good job of summarizing the paper:
The cycling of membrane receptors for substrate-bound proteins via their interaction with the actin cytoskeleton at the leading edge of growth cones and other motile cells is important for neurite outgrowth and cell migration. Receptor delivered to the leading edge binds to its ligand, which induces coupling of the receptor to a rearward flowing network of actin filaments. This coupling is thought to facilitate advance... [T]ransport was dependent on an intact actin cytoskeleton and myosin ATPase...
The following is multiple choice question (with options) to answer.
A thing with cells is going to expand, but first requires | [
"revolving",
"mackerel",
"sweets",
"nourishment"
] | D | a living thing requires nutrients to grow |
OpenBookQA | OpenBookQA-4386 | 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.
A living thing requires what to grow? | [
"support",
"nutriment",
"toys",
"plastic"
] | B | a living thing requires nutrients to grow |
OpenBookQA | OpenBookQA-4387 | javascript, css, ecmascript-6, event-handling, to-do-list
updateCount()
// Toggle Status
document.querySelectorAll('.todo-list li').forEach(item => {
const toggleCheckbox = item.querySelector('input.toggle')
toggleCheckbox.addEventListener('click', event => {
toggleTaskStatusEvent(event.target)
})
})
// ToggleTaskStatus
function toggleTaskStatusEvent(e) {
const liParent = e.closest('li')
liParent.classList.toggle('completed')
updateCount()
}
clear.addEventListener('click', function() {
document.querySelectorAll('.todo-list li.completed').forEach(item => {
item.remove()
})
})
// FiltersButtons
document.querySelectorAll('ul.filters li').forEach(item => {
const filterButton = item.children[0];
filterButton.addEventListener('click', event => {
runFilter(event.target)
})
})
// Function Filter
function runFilter(item) {
const notCompletedItemsFilter = document.querySelectorAll('.todo-list li:not(.completed)')
const completedItemsFilter = document.querySelectorAll('.todo-list li.completed')
const allItemsFilter = document.querySelectorAll('.todo-list li');
var href = item.getAttribute('href')
href = href.split('#/')[1]
const activeButton = document.querySelector('ul.filters a.selected')
activeButton.classList.remove('selected')
item.classList.add("selected")
if (href == 'active') {
The following is multiple choice question (with options) to answer.
Which can be fully toggled back and forth | [
"steam and rain",
"batter and cake",
"wood and ash",
"food and feces"
] | A | a phase change is when matter changes from one state into another state |
OpenBookQA | OpenBookQA-4388 | metabolism, ecology, photosynthesis
Title: Why isn't phosphorus or nitrogen a limiting nutrient for animals? Nitrogen and Phosphorus are usually the limiting nutrient for plants, especially for algae. Phosphorus is used for DNA, ATP and phospholipids, and Nitrogen is used for pretty much every protein a cell might want to produce. That is, their need for biological processes is not tied specifically to photosynthesis: anything that lives is going to need them, pretty much for anything it might want to do. It would make sense for them to be a limiting nutrient for almost anything that's trying to grow, plant or animal.
Yet for animals the limiting "nutrient" seems to always be energy, ie: food. Why aren't animals limited by lack of nutrients in the same way that plants are? Obviously animals need these nutrients, too. Or to reverse the question, why do plants need so much more phosphorus/nitrogen than animals do?
My best guess is that an animal's digestion of plant material is relatively inefficient energy-wise but relatively efficient nutrient-wise. So for an animal to eat enough food to have sufficient energy to survive, it's probably eaten more than enough Nitrogen and Phosphorus for its needs. But I'm just guessing and I can't find any data that would back up that guess. Phosphorus
Your suggestion that if we are meeting our calorific requirement we will be getting enough is true for phosphorus.
Most foods contain lots of phosphorus. The maximum dietary requirement occurs during adolescent growth, estimated at 1250 mg per day. Assuming a calorie intake of 2500 kcal we can calculate a 2500 kcal equivalent phosphorus content for various foods:
skimmed milk contains 7,400 mg phosphorus per 2500 kcal
roasted chicken breast contains 7,500 mg phosphorus per 2500 kcal
cooked white rice contains 3840 mg per 2500 kcal
(Calculations are based upon values obtained via this site.)
Nitrogen
Our requirement for nitrogen is met by our protein intake: inadequate protein intake manifests as kwashiorkor which is essentially due to a dietary deficiency of essential amino acids. In other words, the only way to achieve a nitrogen-deficient diet is to not eat protein, and this would not be alleviated by any inorganic source of nitrogen, even if we could consume enough of such a N source.
The following is multiple choice question (with options) to answer.
What does a four leaf clover need to feed itself? | [
"Irish",
"luck",
"the sun",
"ibex"
] | C | photosynthesis means producers convert from carbon dioxide, water, and solar energy into food for themselves |
OpenBookQA | OpenBookQA-4389 | geology, fossil-fuel, petroleum
For some transport applications, the energy density is still a winning attribute of hydrocarbons: most notably, powered flight for freight and travel.
We already have two routes to non-fossil hydrocarbons: biological sources, and direct chemical synthesis. Each involves capturing atmospheric CO2, and combining with water, to generate a blend of hydrocarbons.
Now, we already have means of creating hydrocarbons suitable for flight (e.g. Jet-A and Jet-A1 fuels). And there are already demonstration plants that have closed-loop generation of synthetic hydrocarbons, for use in electricity-grid-balancing, by using surplus electricity to synthesise methane, which is then burnt in gas turbines when required. Similarly, Tony Marmont's team have been synthesising petrol (gasoline) from air, water, and electricity.
However, none of those things mean that hydrocarbons necessarily have much of a future, beyond plastics production. Because hydrocarbon-powered aviation has a lot of environmental problems beyond just CO2 emissions, in particular it makes other contributions to exacerbating global warming. And there are lots of options for energy storage within the electricity supply chain.
The following is multiple choice question (with options) to answer.
Scientists are experimenting to develop microbes that can live off surplus electricity and CO2 to produce | [
"organic products, such as methane, acetate and butanol as economic biofuels",
"less electricity and more CO2",
"solar energy and biofuels in the laboratory",
"fewer biofuels like butanol and less CO2"
] | A | photosynthesis means producers convert from carbon dioxide, water, and solar energy into food for themselves |
OpenBookQA | OpenBookQA-4390 | paleontology, taphonomy
Title: How are organic walled microfossils preserved in the fossil record? Organic walled microfossils have no hard mineralised parts, how are they preserved in the fossil record? Organic-walled microfossils (wether they be dinoflagellates, pollens, spores or "acritarchs") all have in common to contain an organic compound known as sporopollenin (for the spores and pollens) or dinosporin (for dinoflagellates and, I believe, acritarchs as well). Both compounds have chemical and structural similarities but have appeared independently.
Those compound are incredibly resistant. To give you an idea, to collect siliceous microfossils we first dissolve the sediments with HCl (hydrochloric acid) to get rid of carbonate microfossils. Palynologists (who study such organic-walled microfossils) uses HF (hydrofluoric acid) to get rid of both carbonate and siliceous microfossils (e.g. Doher 1980). Sporopollenin therefore resist to HF, which has a pH of ca. 3. In addition to this, they are also unusually resistant to microbiological degradation (e. g. Gunnison & Alexander 1975).
They are however not resistant to oxydation, hence, probably, why we don't find more of them in the sediments. Additionally, to break sporopollenin walls (in order to study the inner side of those walls) ultrasound can be used (e. g. Lennie 1968).
"Organic-walled" doesn't mean no hard part, it just means no "mineral" hard part.
Sources:
Doher, I., 1980. Palynomorph preparation procedures currently used in the paleontology and stratigraphy laboratories, U.S. Geological Survey. Geological Survey circular, 830: 1-29.
Gunnison, D., Alexander, M., 1975. Basis for the resistance of several algae to microbial decomposition. Applied Microbiology, 29: 729-738.
Lennie, C. R., 1968. Palynological Techniques used in New Zealand. New Zealand Journal of Geology and Geophysics, 11: 1211-1221.
The following is multiple choice question (with options) to answer.
What is the use of organisms preserved in sedimentary rock? | [
"clothing",
"water",
"food",
"fuel"
] | D | organisms can be preserved in sedimentary rock |
OpenBookQA | OpenBookQA-4391 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
In the natural world, camouflage is used by animals to | [
"stand out among their piers",
"avoid being a meal",
"look stylish for others",
"stay warm in the winter"
] | B | camouflage is used for hiding by animals against predators |
OpenBookQA | OpenBookQA-4392 | homework, plant-physiology, plant-anatomy
and 'Vascular Plants = Winning! - Crash Course Biology #37'
https://youtu.be/h9oDTMXM7M8?t=373
[5] Osmosis (water compensating solutes) "In Da Club - Membranes & Transport: Crash Course Biology #5"
https://youtu.be/dPKvHrD1eS4?list=PL3EED4C1D684D3ADF&t=148
Ian (and dad <= all errors and approximations are his :) ).
The following is multiple choice question (with options) to answer.
Plants use the water for their | [
"heart ache",
"emotions",
"buddies",
"fare"
] | D | sugars are transported from the leaves to the roots of a plant |
OpenBookQA | OpenBookQA-4393 | 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.
With wind gusts and green skys you should pack | [
"golf clubs",
"a picnic basket",
"a lightning rod",
"an umbrella"
] | D | if weather is stormy then there is a greater chance of rain |
OpenBookQA | OpenBookQA-4394 | forces, water, surface-tension
Now, if we suddenly boost up this adhesion a billion times stronger (limit: imagination) from what is the real and cohesion stays same, then it's gonna suck. Literally. Everything the water or any liquid comes to contact with, it will immediately start to evenly spread out, clothing every nooks and cranny on that surface of that object. It'd be much like when we spill water on the floor. But now it'd be happening EVERYWHERE, on the sides and on the roofs. The rivers, lakes and oceans start allowing a layer of water to swallow everything up, and a carpet of water will cover the world. Trees and plants burst as there is an immense rush of water inside them. The large droplets of water we adored will never form, a droplet release in the air will torn into tiny minuscule droplets, that we can't see. Maybe into water vapor. And Life? I wonder... ;)
Hope that helped. Went a little overboard. :D
The following is multiple choice question (with options) to answer.
Your clothes likely will be soaked if the skies are | [
"sunny without clouds",
"light blue",
"black",
"clear"
] | C | if weather is stormy then there is a greater chance of rain |
OpenBookQA | OpenBookQA-4395 | velocity
Title: Special Relativity Question: Massive particle racing light I'm a bit rusty on my special relativity and have been thinking about this problem recently:
Suppose that a massive projectile (i.e. something large enough that we could see with a telescope) is ejected from the Sun towards the Earth at 0.9c at $t=0$, for example. Let's approximate that the distance between the Sun and Earth is such that light takes 10 minutes to reach the Earth from the Sun.
After 10 minutes have passed on the Earth, the light from the ejection event reaches the Earth at $t=10$. However, during these 10 minutes, the projectile has traveled 90% of the distance from the Sun to the Earth (i.e. if $d=0$ at Sun and $d=10$ on Earth, then $d=9$ for the projectile at $t=10$ in the Earth's frame). It seems to me that in another 1/0.9 minutes, the projectile will hit the Earth. However, at $t=10$, we will have just seen the projectile leave the Sun. Thus, will it appear as if the projectile travels from the Sun to the Earth in only 1/0.9 minutes? This seems to violate the principle that nothing travels faster than the speed of light. I know that this must be incorrect, but I can't seem to figure it out without dredging up years-forgotten SR. Could anyone point me in the right direction for rectifying this seemingly paradoxical situation? I believe
Thus, will it appear as if the projectile travels from the Sun to the Earth in only 1/0.9 minutes
is a correct statement. (Appear being the key word here). Nothing in this situation actually traveled faster than the speed of light, and the appearance of the object traveling so quickly is an illusion.
A similar illusion and thought-experiment is flicking a laser beam across the surface of the moon, as described and explained here: https://www.universetoday.com/109147/how-a-laser-appears-to-move-faster-than-light-and-why-it-really-isnt/
The following is multiple choice question (with options) to answer.
Which does light from the sun arrive at in final time length? | [
"Uranus",
"Mars",
"Pluto",
"Earth"
] | C | pluto has not cleared its orbit |
OpenBookQA | OpenBookQA-4396 | astronomy, definition, planets, moon
Title: Is there any moon without its planet? Is there any planet without its star?
Is there any moon or any planet wandering in outer space without a definite orbit?
(The name moon or planet used here serves only for size and spherical shape notion.)
João Bosco asked: Is there any planet without its star?
They are called rogue planets, and of course there can also be rogue moons: for example, a regular planet can lose its moon when a rogue planet comes too close and disrupts the system the moon can be ejected.
The following is multiple choice question (with options) to answer.
The last celestial body in our solar system without an orbit is | [
"Saturn",
"Jupiter",
"a meteor",
"Uranus"
] | C | pluto has not cleared its orbit |
OpenBookQA | OpenBookQA-4397 | species-identification, zoology, bone-biology, bone
Title: What is this bone from? This object showed up on my fire escape in New York city. It appears to be some kind of bone. It's a bit smaller than an adult human hand. What animal is it from? Given the size and thin/elongated ilia as well as the urban location, I think a domestic cat and/or a raccoon are likely candidates. I'm leaning toward cat.
Cat pelvis:
VCA Hospitals
Ventral view of domestic cat pelvis; Source: BoneID
Raccoon Pelvis
Anterior view of raccoon pelvis; Source: BoneID
I'm not an expert in differentiating these two species' bones. I will note that your specimen is more or less in between the sizes of these two species. Your size is probably closer to the raccoon, but a cat is just more likely given the location.
The most noticeable trait that stands out to me is the size/pointedness of the ischial tuberosity, which better matches that of the cat.
The following is multiple choice question (with options) to answer.
A proper meal for a raccoon could be | [
"old taco meat",
"a wooden sign",
"a taco truck",
"a soft pebble"
] | A | raccoons eat waste |
OpenBookQA | OpenBookQA-4398 | 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.
raccoons eat what? | [
"debris",
"people",
"fire",
"dirt"
] | A | raccoons eat waste |
OpenBookQA | OpenBookQA-4399 | mechanical-engineering, structural-engineering, metal-folding
Title: How to form steel truck fenders I want to set up steel truck fenders production line, but have no idea how to do that. Something like this picture.
Edit1:
I have two plans to form final curved shape , using a hydraulic press or using a customized rolling machine .
Final products must have no riples . Your raw material will come in the form of a large spool of sheet metal containing a strip of steel hundreds of meters long. You will need an unspooler to feed steel off the spool and a straightener to take the curvature out of the steel strip. Then you need either a punch press or a shear to cut the sheet metal blanks to size and trim their corners. To put ripples or corrugations into the cut blanks, you will need a roller die or a rolling mill. To put a folded edge onto the sides of the blank you will need either a bending brake or a set of progressive dies. To bend the fenders into their final curved shape you will need a sheet metal press and to smooth out any resulting ripples you will need an ironing press.
To attach the mounting brackets you will need an electric spot welder. Finally, you will need either an electrostatic spray booth to paint them or a powder coating rig.
The following is multiple choice question (with options) to answer.
If you wanted to make a metal bed frame, where would you start? | [
"search for rocks",
"make dinner",
"slice bread",
"dump out water"
] | A | alloys are made of two or more metals |
OpenBookQA | OpenBookQA-4400 | geomorphology
Title: What causes these mound-like ground formations? Whilst riding on Mam Tor in Castleton, England I came across this scene (not my photo) and I would like to know what causes the formations which I have ringed in red. They look like piles of earth have been deposited a long time ago, but clearly that can't be the case, so what causes them?
Another image of these mounds They're landslide deposits; Mam Tor gets its name, which translates as "mother hill", from the regular landslides that come off the higher slopes and form hillocks further down into the valley.
The following is multiple choice question (with options) to answer.
What causes erosion? | [
"salads",
"concrete",
"gales",
"cars"
] | C | wind causes erosion |
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