source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-4701 | homework-and-exercises, pressure
Title: Necessary air pressure in flexible vessel to lift a certain mass I have the following situation in mind:
A big airtight bag of arbitrary shape with a person standing on it. The bag gets inflated with air to lift the person.
Assuming that the bag is much larger than the persons footprint, how do I find the minimal overpressure in the bag that I need to lift the person of the ground?
I was thinking of just dividing the normal force of the standing person by the footprint area, but I am not sure on that approach
$$F_n = 80×9.81 = 784\text{ N}$$ $$P_n = \frac{784}{0.2×0.3} = 13066\text{ Pa}$$
I have the feeling that the bag dimensions play a role as well, as intuitively I would say that to do this, a small bag would work better than a big bag, but again I'm not sure... It is just as simple as you suggest. At the moment my feet are exerting a pressure on the ground of my weight divided by whatever the area of my shoes is and the pressure exerted by the ground on me is what keeps me stationary. Exactly the same applies to your air bag. once the air pressure is the same as the pressure you exert on the bag it will support you.
But there are a couple of extra things to consider. When you stand on the bag you will compress the air in it and you'll sink until the air is compressed enough to match the pressure of your shoes. So the initial pressure can be lower than your shoe pressure and the bag can still keep you off the ground.
You mention the bag size, it's probably easier to compress the gas a lot in a small bag than in a large bag, so a small bag would probably work better. There's nothing especially fundamental about this; it's just that a large bag allows more room for the air to move into as your feet compress it.
The following is multiple choice question (with options) to answer.
Standing on a plastic tote will | [
"vaporize it",
"deform it",
"levitate it",
"melt it"
] | B | if a flexible container is pushed on then that container will change shape |
OpenBookQA | OpenBookQA-4702 | classical-mechanics
Finally, raw force is probably the dominant factor here. Pushing allows you to use the full strength of your muscle, which is probably somewhere around your weight (with a rather large spread). On the other hand, hitting allows you to accumulate the strength of your muscles over the duration of the swing, allowing you to impart much bigger forces than would be possible with just pushing. Try driving nails just by pushing the hammer, and you'll see the difference rather easily - the only benefit you'll get from using a hammer is that you're not going to feel as much pain as when pushing against the much smaller nail head.
The following is multiple choice question (with options) to answer.
Pushing a little kid on a swing is easy because they are light. It will require more strength to push when | [
"when he loses weight",
"when he eats chicken",
"seventy four plus five",
"he's older and heavier"
] | D | as the mass of an object increases , the force required to push that object will increase |
OpenBookQA | OpenBookQA-4703 | 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.
Which of the following would be reason for animals to leave their environment? | [
"Hurricane",
"Temperature",
"Predators",
"Illness"
] | A | natural disasters can cause animals to leave an environment |
OpenBookQA | OpenBookQA-4704 | planet, orbit
Title: Do the orbits of planets change sometimes? Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it? Yes, the orbits change massively over time. For example, Earth's eccentricity (how close to a circle the orbit is), its axial tilt (what causes seasons), and precession (which direction the Earth's spin axis points) change on these huge cycles, tens of thousands to hundreds of thousands of years long. They are caused by the pull of the other planets, mainly Jupiter and Saturn (since they are so huge), as well as the physics of inertial reference frames. These are known as the Milankovitch cycles. Here is a neat video explaining what each of the cycles are in detail. That video is about Earth, but the same concepts apply to all the other planets too, just on different amounts and timescales.
An asteroid hitting a planet would technically change its orbit, however how much is questionable. An asteroid a couple km across would barely nudge the Earth since the Earth is bigger by many orders of magnitude. It would also destroy everything on the planet, but thats another story. Way back in the solar system's formation, when Thea hit Earth (theoretically) it was much closer in size than the Earth, so no doubt that it caused a much more significant shift in orbit.
The following is multiple choice question (with options) to answer.
What entity does the earth orbit that causes the seasons to change? | [
"mercury",
"venus",
"pluto",
"plasma star"
] | D | planets orbit stars |
OpenBookQA | OpenBookQA-4705 | atmosphere, carbon-cycle
Title: For a tree over its entire existence, does it actually have a net negative effect on atmospheric CO2? A tree while alive converts CO2 + water -> carbohydrates + O2. However, once the tree dies, it decays, releasing CO2 back into the atmosphere. My question is, over an individual tree's overall existence, does a tree actually contribute to a reduction in atmospheric CO2?
I'm aware there's other pathways a tree could end up as a more long term carbon store (carbonaceous rocks), but mostly interested in if a tree were to die and fall in a forest, decay in 50-150 years, would it have contributed to a net reduction in CO2, or does a tree typically act as more of a temporary 100+ year store of CO2? A brief review of recent non-paywalled available literature indicates that such an effect likely exists but that it is difficult to quantify based on currently available data.
Some amount of carbon from trees can be sequestered in the soil for periods time significantly longer than the typical above-ground decomposition time of organic matter, potentially for millennia. This clearly lengthens the carbon cycle time, but it is not clear to me whether this represents carbon storage, as there does not seem to be a well established minimum cut-off time for this. The primary source for soil-sequestered carbon are tree roots, with leaf litter constituting a secondary source.
The following paper (preprint online) addresses the question in the specific context of agroforestry, i.e. cropland interspersed with trees. The paper notes multiple times that the processes involved in soil sequestration are not well understood and that quantitative measurements and estimates vary widely, as one would expect based on differences in climatic and soil condition. Note on units: A Mg corresponds to a metric ton.
Klaus Lorenz and Rattan Lala, "Soil organic carbon sequestration in agroforestry systems. A review." Agronomy for Sustainable Development, Vol. 34, No. 2, April 2014, pp. 443-454.
The following is multiple choice question (with options) to answer.
Plants and trees suck up carbon dioxide, so if trees are cut down, carbon levels will | [
"cry",
"fly",
"escalate",
"go down"
] | C | as the population of plants decreases , carbon in the atmosphere will increase |
OpenBookQA | OpenBookQA-4706 | zoology, behaviour, mammals, rodents
Title: Why do Guinea Pigs chirp / sing? Ok, so this appears to be quite a mystery. Me and my girlfriend have 2 Guinea Pigs, 1 male and 1 female.
My girlfriend once picked up the female one and took her outside into our garden. The Guinea got scared for some unknown reason and jumped out of my girlfriend's arms and fell down hard.. That night, the female Guinea woke us up with some very strange sounds. She sounded like a chirping bird.
Since then, she sometimes repeats these sounds (most often at night, but not always). Mostly, we are puzzled as to why as there is often no apparent reason for her sounds. Also, when she makes the sounds, she appears to be in a trance-like state, making no movements at all.
Looking for the answer online I found many discussions on the subject like this one or this one. Mostly, the sounds (and the often mentioned trance like behavior) appear to be interpreted as either (1) alarm sounds, (2) loneliness sounds or (3) happiness sounds.
There are also recordings of it one Youtube, like this one.
What I was wondering:
Does anybody know about some actual research that has been committed on this subject? If so, what were the results?
I'm just so very curious to find out! I found this question very interesting so I did some research. Here's a brief summary of what I've found:
Researchers have found that there are 11 different call types. Some of these include a "sharp alarm cry", "sociable clucking", chutter, whining, purring etc. Using body position and behaviour, researchers attempted to associate these vocalizations with behaviour. Some vocalizations had no apparent associated action including what researchers designated the "chirrup" ( I think this is similar to what your guinea pig might have emitted.)
For more information you can read the results section of this paper by Berryman. You can find a full description of each of the 11 calls and their assumed cause or purpose. Some involve social interaction, reproduction, and distress. Much of the research regarding Guinea pig vocalization involves communication and response between mothers and pups.
In short, it seems as though this chirping behaviour your Guinea pig is exhibiting is normal, but not of any known cause.
The following is multiple choice question (with options) to answer.
Which is likeliest to make noises from its mouth? | [
"a fish",
"a truck",
"a chicken",
"an ant"
] | C | chickens cluck |
OpenBookQA | OpenBookQA-4707 | volcanology, volcanic-hazard
Title: How long will red hot lava from the Sundhnúkur eruption in Iceland be visible? I'll be in Iceland in a few weeks and would love to see glowing red hot lava, however, the recent Sundhnúkur eruption just ended, after erupting for three days. So no new lava is being pumped out, I guess, but I imagine it'll take the lava that's already come out some time to cool.
My question is... how long will it take for the lava to cool such that it's not glowing red? I have experienced a similar situation two years ago. I visited the site of the 2021 Fagradalsfjall eruption on November 18, 2021, exactly two months after the last emission of lava (and one month before the Icelandic Met Office declared the eruption officially over on December 18). We walked on top of the solidified crust of the lava pond to reach the main vent (don't do it, see below). There were some fissures in the crust, like this one, about 20 cm wide:
And if you looked inside the fissure, you could actually see some red glowing lava at the bottom, maybe 3 meters deep:
Nothing impressive, and maybe not what you had in mind, but it definitely qualifies as "red hot lava", two months after the magma supply had ended. That being said, here are some thoughts about your trip plans:
The eruption may be over, but the area is still closed for the time being. Here is the current hazard map, valid until December 29 (check for updates to see how the situation evolve).
Compared to other countries, Icelanders usually have very relaxed
rules regarding access to eruption sites (the freedom to access
private lands is a cultural thing called almannaréttur and is even
written in law). So if the access is forbidden, it means Iceland
authorities have very good reasons to do it.
Indeed, there is still ground inflation measured in the area, below the Svartsengi geothermal plant. It means that magma accumulation has resumed and another eruption is already on its way, although it could take weeks or months. It could be during your stay if you're lucky—and if access is allowed...
The following is multiple choice question (with options) to answer.
A bunch of lava that is sitting somewhere could create on its own | [
"an icy, frozen villa",
"a flat raised area",
"a new oak tree",
"a happy landscape portrait"
] | B | a plateau is formed by a buildup of cooled lava |
OpenBookQA | OpenBookQA-4708 | 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.
A typhoon can potentially cause | [
"diminished lakes",
"overflowing wetness",
"population floods",
"rivers drying"
] | B | heavy rains cause flooding |
OpenBookQA | OpenBookQA-4709 | homework-and-exercises, newtonian-mechanics, energy, energy-conservation, work
Title: Change of kinetic energy of a rock lifted by a force greater than its weight
A rock is lifted for a certain time by a force $F$ that is greater in magnitude than the rock’s weight $W$. The change in kinetic energy of the rock during this time is equal to the
A. work done by the net force ($F - W$)
B. work done by $F$ alone
C. work done by $W$ alone
D. difference in the potential energy of the rock before and after this time.
The correct answer is A. I understand why this is so: The work–energy theorem states that the net work done on an object is equal to its change in kinetic energy.
What I’m having trouble understanding is why answer choice D is incorrect. If a rock is falling from a given height, the rock’s change in kinetic energy (which goes from $0$ to $\frac{1}{2}mv^2$) is equal to its change in potential energy (which goes from $mgh$ to $0$). What is different about the scenario presented in the problem that doesn’t make D correct? In this question the rock is the system which you are asked to consider and the rock by itself does not have gravitational potential energy.
It is the rock and Earth system which possesses gravitational potential energy.
When a rock falls and you are treating the rock as the system the gravitational force of attraction on the rock by the Earth is an external force which is doing work on the rock.
Having the rock and the Earth as the isolated system there are no external forces acting on the system.
The gain in kinetic energy of the system (rock and Earth) is equal to the loss if gravitational potential energy of the system.
The gain in kinetic energy of the Earth is usually neglected because it is so small compared with the gain in kinetic energy of the rock.
The following is multiple choice question (with options) to answer.
Even items such as rocks mass can be changed due to which process? | [
"Weathering",
"Climate",
"Weatherization",
"Weather"
] | A | weathering means breaking down surface materials from larger whole into smaller pieces by weather |
OpenBookQA | OpenBookQA-4710 | matter
When a solid is dissolved in a liquid, is it still a solid
I want to touch on this too, because there's a useful subtlety here.
When you put salt in hot water, it dissolves. In this case the energy from the water is enough to overcome the attraction between the atoms, and it is pulled off the crystal to mix with the water. So you don't have water and salt any more, you have a mixture of Na ions, Cl ions, and water molecules. Or saltwater.
Now compare this to what happens when you salt and sugar. In this case the two happily sit together as a mixture, but they are not changed in form. They're also quite tasty, as salted caramel attests. If one of the two you mix is a liquid, like powder in water, then you have a suspension. In these cases the original materials remain in their original forms, just mixed together. This is different than the saltwater case, which is not simply salt and water in the same bottle.
The following is multiple choice question (with options) to answer.
sugar dissolves in what when they are combined? | [
"dirt",
"ocean liquid",
"honey",
"air"
] | B | sugar dissolves in water when they are combined |
OpenBookQA | OpenBookQA-4711 | thermodynamics, pressure, atmospheric-science, density, air
Title: Why does air pressure decrease with altitude? I am looking to find the reason: why air pressure decreases with altitude? Has it to do with the fact that gravitational force is less at higher altitude due to the greater distance between the masses? Does earth’s spin cause a centrifugal force? Are the molecules at higher altitude pushing onto the molecules of air at lower altitudes thus increasing their pressure? Is the earths air pressure higher at the poles than at the equator? The air pressure at a given point is the weight of the column of air directly above that point, as explained here. As altitude increases, this column becomes smaller, so it has less weight. Thus, points at higher altitude have lower pressure.
While gravitational force does decrease with altitude, for everyday purposes (staying near the surface of the Earth), the difference is not very large. Likewise, the centrifugal force also does not have significant impact.
The following is multiple choice question (with options) to answer.
As altitude increases air pressure will do what? | [
"increase",
"rise",
"fly",
"plummet"
] | D | as altitude increases , air pressure will decrease |
OpenBookQA | OpenBookQA-4712 | general-relativity, forces, gravity, earth, atmospheric-science
Title: How does Earth hold its atmosphere? According to Einstein's theory of relativity, gravity is not pulling us down but space is pushing us down. This mean there is no gravity and its an illusion. So, in this scenario how does Earth hold its atmosphere? Since there is no force to pull it down.
This mean there is no gravity and its an illusion
This is a very common statement in popular science accounts of general relativity, and while it's true it's also misleading.
If you release an object above the Earth then that object will immediately start accelerating towards the Earth. Isaac Newton would say this is because there is a force pushing the object towards the Earth and that's what we mean by the gravitational force. Albert Einstein would say there is no force pushing the object towards the Earth and the object accelerates towards the Earth due to the curvature of spacetime. It is in this sense that we say gravity isn't really a force.
But in both cases the object accelerates towards the Earth, and if the object is an air molecule then that air molecule accelerates towards the Earth. So the Earth's atmosphere stays with the Earth because the air molecules that make up the atmosphere are all individually accelerating towards the Earth just like any other object does. The fact the atmosphere is bound to the Earth is no more surprising than the fact you and I are also bound to the Earth.
I suppose the surprising thing is why the atmosphere doesn't all fall immediately to the Earth's surface to form a thin dense layer of air molecules. The reason this doesn't happen is that air molecules are all whizzing around at surprisingly high speeds - typically hundreds of metres per second depending on the temperature. The air molecules bash into each other and knock each other around, and the air molecules near the ground bash into the air molecules above them and stop them falling down.
The following is multiple choice question (with options) to answer.
As the pull of gravity decreases air molecules | [
"explode",
"disperse",
"crowd together",
"party"
] | B | as altitude increases , air pressure will decrease |
OpenBookQA | OpenBookQA-4713 | evolutionary-game-theory
Title: What are examples of genes succesfully reproducing in ways that is in conflict with helping the individual creating offspring Most of the time, our genes have common interests with our "self".
We reproduce well if and only if our genes reproduce well.
In some cases, like in bees, the haploid bees can survive better if they help their queen reproduce.
In humans and other species, are there samples that give individuals "incentive" to help non family member to reproduce for the sake of their genes.
So
No filial altruism
No reciprocal altruism
So I need a sample between individual based evolution and gene base evolution.
For example, many genocide are done against the best and brightest. I wonder what sort of genes encode "kill the best and brightest" and how does that kind of gene survive well in the gene pool? The prototypical example of this is t, whose existence was predicted by Robert Trivers and featured prominently in the Selfish Gene. The current dominant point of view in evolutionary biology is that genes act in their own interest and even the 'self' is just a manifestation of the gene's reproductive properties.
t is a locus in some male mice. The t gene characterizes very well the selfishness of a selfish gene. While most paternal genes are found in 50% of offspring, t is found in over 3/4 of offspring. Somehow it manages to reproduce at the expense of the other loci in the male mouse. t itself is not known to convey any advantages to its host organism. the males tend to be smaller and sometimes even reproductively disadvantaged.
Does that go some way to answering this question?
Animal behavior such as cheating or adopting are often interpretable as reproductive advantages. Killing the best and brightest definitely are to the advantage of those who are doing the killing. This SNL Skit has always said it best to me. "... and now I am smart!". Such kill offs so rarely include killing one's own offspring. I'm not sure they can be called in conflict with reproductive advantage. EO Wilson's essay "On Human Nature" does a reasonable case for saying that wars and famines are in fact produced by evolutionary advantage, however cruel and ugly they may be.
The following is multiple choice question (with options) to answer.
An example of an offspring receiving a gene is | [
"cooking",
"driving",
"cartwheels",
"moles"
] | D | offspring receive genes from their parents through DNA |
OpenBookQA | OpenBookQA-4714 | everyday-chemistry, experimental-chemistry
Title: Confusing definition of the term precision According to the textbook, we say a measurement is precise when series of measures are close to each other.
But in real use, I feel like the term is used in a different meaning.
For example, scale A weighs to cube of lead and displays 10.5g while scale B displays 10.4977g.
In this case, one say the measurement made by scale B is more precise than that of A. That is, scale B can distinguish more fine weights than A.
Isn't this usage of the word precise different from textbook definition? Please explain clearly the real usage of the term precise. In colloquial English, precision is synonymous with accuracy. If you look it up on Google, the first definition is:
the quality, condition, or fact of being exact and accurate.
In the field of science, however, it takes on another meaning:
the degree to which repeated measurements under unchanged conditions show the same results
There is also measurement resolution:
the smallest change [an instrument] can detect in the quantity that it is measuring
Which is similar to the definition precision takes on in numerical analysis:
the resolution of the representation, typically defined by the number of decimal or binary digit
In short, precision can take on different meanings depending on how you choose to apply it. If you talk about the precision in a set of measured data, you will be using the scientific definition; if you talk about the precision of an instrument, you will be using the numerical analysis definition.
The following is multiple choice question (with options) to answer.
A scale is used to measure what? | [
"tallness",
"height",
"length",
"fatness"
] | D | a scale is used for measuring weight |
OpenBookQA | OpenBookQA-4715 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
Wind is a resource we can renew because there is an | [
"seven",
"endless supply",
"nothing",
"limited supply"
] | B | wind is a renewable resource |
OpenBookQA | OpenBookQA-4716 | organic-chemistry, combustion, environmental-chemistry, atmospheric-chemistry
I'm suspicious this may just be ethanol, but the manufacturer swears it isn't.
The advertised ratio is 1 oz to 12.5 gallons of fuel which is less than 0.1% (I believe they used double that in the tests). Too low to be ethanol anyway, right?
Follow-up:
I have confirmed that I was originally mistaken in that all measurements are ppm. I received a new copy of the original results, and $\ce{CxHy}$ and $\ce{CO2}$ are indeed measured in percent, rather than ppm. It was incorrectly rewritten in the report. The numbers are the same, though. With reference to the discussion in the question comments, this product does not appear to appreciably reduce carbon emissions in total. It does however appear to reduce carbon monoxide emissions. As carbon monoxide is a product of incomplete combustion, it is plausible that the additive is helping the fuel burn more completely. Broadly speaking, you would hope that the majority of the carbon in your exhaust gas would come out as carbon dioxide, which is 'merely' a greenhouse gas and not truly nasty like CO or PAHs. Prior to the advent of catalytic converters, carbon monoxide poisoning by vehicle exhaust was a much greater risk.
It should be noted that conservation of mass tells us some powerful things about what to expect from an engine - namely that the carbon that goes in to the engine as a component of fuel must come out as exhaust gasses, particulates, polycyclic aromatic hydrocarbons etc., or else be sequestered inside the engine (though the latter is achievable by putting a banana into the exhaust pipe, it is generally done as a prank).
Reduction of carbon emissions in general is achieved through obtaining more work per mass of fuel burnt, which, when coupled with the mass and other design features of the car confers the fuel efficiency. Unfortunately, the data provided don't tell us anything about that. The more complete burning of the fuel, evinced by the reduction of CO concentration in the exhaust gas does imply some increase in efficiency, however CO is a very small component of exhaust gas, indicating alongside the low concentration of unburnt hydrocarbons that the fuel is already burning virtually to completion.
The following is multiple choice question (with options) to answer.
Ethanol sometimes might be | [
"concocted",
"love",
"magic",
"affection"
] | A | ethanol sometimes is made of corn |
OpenBookQA | OpenBookQA-4717 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Other than sight bloodhounds can find a meal by | [
"social media",
"their phone",
"the internet",
"stench"
] | D | smell is used for finding food by some animals |
OpenBookQA | OpenBookQA-4718 | ocean, ocean-currents, tides
Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.
The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals) and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.
A good review of possible effects on benthic organisms is provided by Shields et al (2011). These may include,
The following is multiple choice question (with options) to answer.
As water increases in an environment the number of aquatic animals such as zooplankton, nekton, and benthos will | [
"on the up",
"fall",
"stagnate",
"face extinction"
] | A | a body of water is a source of water |
OpenBookQA | OpenBookQA-4719 | entomology, ethology, parasitology, ant, parasitism
Title: The emergence of Phengaris butterflies from ant nests The butterflies of the Phengaris genus (also known as Maculinea) are known to be brood parasitic. During the fourth instar, the caterpillars leave their food plant and mimic ant larvae, causing the ants to take them back to their nest as if they were ant larvae that had escaped.
While in the nest, the caterpillars mimic ant larvae by means both of surface chemicals and acoustic mimickry (including, I understand it, mimicking sounds made by queens!) After pupating, the pupa continues to engage in acoustic mimickry, although I can't find any reference to whether it does (or even could!) engage in continued chemical mimickry.
But I can't find anything in the literature regarding the adult butterfly's emergence from the pupa and exit from the ant nest. A non-academic book and some web pages claim that the alcon blue (Phengaris alcon) and mountain alcon blue (Phengaris rebeli) adults are no longer engaged in any form of mimickry at this point, and may be attacked by the ants. These accounts differ as to how likely an attack is, how much danger the butterfly is in, and the level of protection afforded by the butterfly scales.
The webpages I mention belong to a University of Copenhagen researcher (Dr. David Nash) who has published work in this field. This suggests that the claim is probably correct.
That said, none of the peer-reviewed publications coauthored by him appear to mention it, and each of the two webpages creates a different impression as to the level of danger involved:
"If an ant tries to bite the butterfly it will only get a mouthful of scales." states one, suggesting that there is little the ants can do to harm or hinder the butterfly. But the other states "The adult has to get out of the ant nest quickly to prevent the ants killing it."
The book is written by someone else. It cites three papers, which do discuss the larvae/pupae and ants. But none of these have any information regarding this specific topic.
The following is multiple choice question (with options) to answer.
mimicry is used for avoiding predators by animals by camouflaging as what kind of animal? | [
"frightful",
"weak",
"tame",
"vulnerable"
] | A | mimicry is used for avoiding predators by animals by camouflaging as a dangerous animal |
OpenBookQA | OpenBookQA-4720 | entomology, sensation
Title: Do butterflies see behind? Butterflies, like many other insects, understand that I am getting near from behind. How do they feel this - through vision, hearing, or some other sense? Short answer
Butterflies can see behind them.
Background
Merry et al. (2006) have estimated the field of view of the butterfly, by investigating the Orange Sulphur butterfly (Colias eurytheme):
Colias eurytheme. Source: Massachusetts Butterfly Club
The authors found that this butterfly has a very large visual field, encompassing
93% of the spherical space around the animal. There was a small blind spot behind the head not seen by either eye. Another study by the same group showed similar results in another species of butterfly, the Empress Leilia (Asterocampa leilia). Here is a picture of the estimated binocular field of view of the Orange Sulphur, revealing that the animals' vision is virtually spherical, with only a small blind spot at the back (the white area):
Source: Merry et al., 2006. Grey is the field of view, white the blind spot posteriorly. Cardinal directions are indicated (Dorsal, Ventral, Posterior, Left and Right).
Here are a few pictures of other species of butterfly that show the protruding compound eyes covering a large field of view:
Sources: Alex Sukonkin and PhotographersDirect
The feature of large visual fields in insects is, however, not restricted to butterflies (Lutowski & Warrant, 2002). Another insect I often try sneak upon to take pictures are dragon flies, and more often than not they fly away regardless of the angle I approach them. They too have these large compound eyes with a field of view extending to the back:
Source: Nature North
References
- Lutowski & Warrant, J Comp Physiol 2002;188:1-12
- Merry et al., J Insect Physiol 2006;52:240–8
The following is multiple choice question (with options) to answer.
Butterflies will often times have coloring that at look like eyes on their wings for | [
"to look pretty",
"fun",
"to see flowers",
"protection"
] | D | mimicry is used for avoiding predators by animals by camouflaging as a dangerous animal |
OpenBookQA | OpenBookQA-4721 | thermodynamics
Title: Does a gas condenses above its dew point? We all know that at temperatures much below the boiling point, evaporation occurs and liquid/vapor equilibrium exists.
So if we have steam at temperature greater than dew point, does it undergoes condensation at that temperature? Let's, for simplicity, consider a closed container with a liquid. In such closed system, evaporation and condensation happen simultaneously.
The rate of evaporation increases with temperature. The rate of condensation, which happens when vapor molecules hit the surface of the liquid, depends on the vapor pressure.
At equilibrium, the rates of evaporation and condensation are the same and the temperature is a dew point, by definition.
If the temperature is raised above that point, the rate of evaporation will exceed the rate of condensation, but, the condensation will still occur. This will continue until the new equilibrium is achieved, with the new temperature becoming a new dew point.
So, for a closed system, condensation does happen at temperatures above the dew point.
In an open environment, when the vapor does not come in contact with liquid, the condensation, generally, should not occur above the dew point.
The following is multiple choice question (with options) to answer.
condensation is a stage in what cycle process? | [
"h2o",
"space",
"solar",
"fire"
] | A | condensation is a stage in the water cycle process |
OpenBookQA | OpenBookQA-4722 | fusion, renewable-energy
An energy "breakthrough" would be a loaded development. We already use lots of energy, and if we found it economic to use more we probably would. The last breakthrough shift in our ability to exploit energy resources rocketed the entire planet into a new geological era, the Anthropocene. We called this change the industrial revolution. Some obscure project that ARPA-E funded with $500,000 could cause the next industrial revolution. The implications of such a change would probably be beyond any of our imaginations.
The following is multiple choice question (with options) to answer.
Which would mandate replacing natural resources? | [
"camping",
"a national park",
"overlogging",
"a garden"
] | C | An example of replacing a natural resource is planting new trees where a forest once stood |
OpenBookQA | OpenBookQA-4723 | java, random, io, generator
public ArrayList<String> draftPlayers(ArrayList<String> players){
for (int i=0; i<players.size(); ++i){
String pick = JOptionPane.showInputDialog("Pick #" + (i+1) + ": \nEnter your draft selection for the " + players.get(i));
if(pick != null){
picks.add(pick);
}
else {
break;
}
}
return picks;
}
public ArrayList<String> createDraft(ArrayList<String> order, ArrayList<String> picks) {
for (int x=0; x<picks.size(); ++x) {
if((order.get(x)!= null) && (picks.get(x)!= null)) {
draft.add((x + 1) + ". " + order.get(x) + ": " + picks.get(x));
}
}
return draft;
}
public void printDraft(ArrayList<String> draft){
if (numRounds == 0) {
System.out.println("Draft cancelled!");
}
if (numRounds >= 1) {
System.out.println("\nRound 1: \n");
for (int x = 0; x < 30; ++x) {
System.out.println(draft.get(x));
}
}
if (numRounds >= 2) {
System.out.println("\nRound 2: \n");
for (int x = 30; x < 60; ++x) {
System.out.println(draft.get(x));
}
}
if (numRounds >= 3) {
System.out.println("\nRound 3: \n");
for (int x = 60; x < 90; ++x) {
System.out.println(draft.get(x));
}
}
The following is multiple choice question (with options) to answer.
At the end of their season lumberjacks will seed a new | [
"batch of chickens",
"track of land",
"popcorn machine",
"home garden"
] | B | An example of replacing a natural resource is planting new trees where a forest once stood |
OpenBookQA | OpenBookQA-4724 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
You find a furry creature walking around. What feature would also describe this animal? | [
"dead, cold-blooded, and scaly",
"cold, cold-blooded, hungry, alive",
"horned, warm-blooded, hungry, alive",
"warm, warm-blooded, and also dead"
] | C | a mammal is warm-blooded |
OpenBookQA | OpenBookQA-4725 | 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.
What is part of an ecological system? | [
"waterfalls",
"pulsars",
"black holes",
"asteroids"
] | A | an ecosystem contains nonliving things |
OpenBookQA | OpenBookQA-4726 | biochemistry, microbiology, microbiome
„the higher the potential, the higher the dissolved oxygen in medium“.
I think the wording is misleading, since high redox potential is a consequence of oxygen being present, not the other way around (as that would imply something like high redox potential attracting atmospheric oxygen into water). I speculate that the author meant that dissolved (organic) compounds tend to release $O_2$ (or rather any reactive oxygen species (ROS)) more often in an oxidative milieu.
The following is multiple choice question (with options) to answer.
If something is in an ecosystem, it could be | [
"invisible",
"vacuum of space",
"lacking life",
"alien"
] | C | an ecosystem contains nonliving things |
OpenBookQA | OpenBookQA-4727 | Here is one solution in $12$ pieces.
• Six of the pieces here only have crust on one corner, but didn't the problem say absolutely none? – Trejkaz Sep 2 '13 at 5:29
• @Trejkaz: The requirement is only that the measure of crust included in some piece $A_i$, i.e. $\lambda(A_i \cap \partial D)$, be 0. A single point of idealized zero-thickness crust is OK since that has measure 0. – The_Sympathizer Sep 2 '13 at 5:43
• Someone has to ask this: What if we really require $A_i\cap \partial D = \emptyset$ for at least one $i$, that is at least one piece, including its boundary, must lie entirely in the interior of the disk? – Jeppe Stig Nielsen Sep 2 '13 at 21:48
• @JeppeStigNielsen: that appears to be an open problem – Robert Israel Sep 2 '13 at 22:22
• @mike4ty4 It's fair enough to have ideals, but someone who is thinking more about the pizza than the semantics will probably consider a 0-width crust to be less than ideal. Illustrating the danger of stating mathematical problems in real-world terms which people might relate with. :D – Trejkaz Sep 3 '13 at 6:45
If this violates the parameters in a clear way, consider this a teaching opportunity. Would this count:
The following is multiple choice question (with options) to answer.
The crust is made of different kinds of | [
"flour",
"pastries",
"stars",
"stone"
] | D | Earth is made of rock |
OpenBookQA | OpenBookQA-4728 | reproduction, human-genetics, human-genome
I missed the "as a species" part of your question. Inbreeding will only likely have an effect within small, closed populations, though it will continue to have a lasting effect even as those populations grow and open up. Two textbook examples are French Canadians and Ashkenazi Jews. Even now, there is continued elevated risk of certain rare genetic diseases in these populations. As for the species as a whole, it is likely to be really detrimental only if the effective population size of the species becomes really low: a general rule of thumb used by conservation biologists is that the effective population size should be at least 50 to avoid the effects of inbreeding (and 500 to avoid the effects of genetic drift) (50/500 rule).
Sorry about the confusion.
The following is multiple choice question (with options) to answer.
If a species of animal is endangered or going extinct, it's because too many of them have stopped | [
"mating",
"hugging",
"nothing",
"dying"
] | A | if members of a species are born then the population of that species increases |
OpenBookQA | OpenBookQA-4729 | thermodynamics, phase-transition, metals, liquid-state
A correct microscopic picture of the melting transition
The different behavior of many observables characterizes crystalline solids and liquids. However, we should not forget that amorphous solids exist, blurring many possible characterizations of the transition based on the concept of spatial order or, on average static quantities. Dynamical properties remain a much clearer indication of the passage from a solid to a liquid phase. In particular, the apparently simple concept that liquid flow and solid don't is a good starting concept to build intuition on the melting process.
Here, I'll try to underline a few (correct) ideas one can connect to the fact that liquids flow.
The following is multiple choice question (with options) to answer.
Which is an example of solid matter | [
"an egg in a carton",
"molten copper in a vat",
"water in a glass",
"mercury in a thermometer"
] | A | Matter in the solid phase has definite shape |
OpenBookQA | OpenBookQA-4730 | Unfortunately there are two different types of clock. In one type, the minute hand moves smoothly with the second hand. Lets consider this case first.
After 60 seconds the minute hand has moved to position 1. This means that after 60 seconds there has still only been 1 counted coincidence (the starting position). After 120 seconds there has been a second counted coincidence, and the minute hand has moved to position 2. This pattern continues for 3540 seconds without deviation and we have 59 counted coincidences, with the minute hand on the 59th position and the second hand on the 0th position. We note that in 60 more seconds we will have the starting condition again; so after a second iteration of the above, we will have 118 counted coincidences, with the minutes hand on the 59th position and the second hand at the 0th position. After 60 more seconds, we have our final coincidence at exactly 4pm, and the final count is 119.
However, there is a second type of clock where the minute hand stays perfectly still until the second hand strikes the 0th position, after which point, the minute hand jumps to the next position. On this type of clock, the two hands coincide at the 0th second, then the minute hand jumps to position 1, and the two hands coincide again at the 1st second. We then follow the logic of the previous case, and we find that each iteration offers exactly one more coincidence. Since we have two iterations to consider, we have a final count of 121. (And at 4pm and 1 second we would have a count of 122, but this is outside of the range of counts). If your book offers 121 as an answer, it is probably thinking about this style of clock.
PS. It also depends on what is meant by 'between': usually this either includes both endpoints or it doesnt. If the coincidences at exactly 2pm and 4pm are disallowed, then either 117 or 119 are acceptable, depending on the type of clock.
We want the angles of each hand to line up, and we want to count how many times this happens after 2pm until 4pm. This solutions uses the concept of radians, period, and angular velocity to tackle this.
The following is multiple choice question (with options) to answer.
What typically occurs between a sixth and a half of a minute? | [
"a volcano",
"a television series",
"an hour",
"an earthquake"
] | D | a tectonic plate moves along a fault line |
OpenBookQA | OpenBookQA-4731 | evolution, ecology, natural-selection, adaptation
Title: What are Some Classical Examples of Local Adaptation? Question
Can you please give a list of classical (textbook) examples of local adaptations?
How to answer
Examples don't necessarily need to include what evidence supports this specific example of local adaptation. A simple description of the local adaptation (e.g. coat colour changes from black on dark soil to white on light soil) and an brief explanation of the reason (e.g. because being nicely camouflaged prevents from predation from hawks) is enough.
I think a list of 10 or more such examples would be great.
Definition of local adaptation
Note that I define here local adaptation as differentially adapted subpopulation of a single species (with existing gene flow between subpopulations especially for sexually reproducing species).
Justification for the question
I found surprisingly complicated to find such list online. I think it could be a valuable post for many.
Examples
Examples of local adaptation (that you are free to add in your answer with a description) include beach mice camouflage, altitude adaptation in tibetans and peppered-moth camouflage. Adaptation is a change in a trait as a response to selection. As you ask for local adaptation I assume you want examples where sub-populations have either come under different selection and adapted differently, or cases where sub-populations have come under similar selection but not all have had the necessary genetic variation to evolve, i.e. selection has caused differentiation between sub-populations. Local adaptation can lead to varying degrees of divergence, so some for some examples it may be worth exploring speciation events. Here's some examples:
Galapagos Tortoises
There are two general shapes to the shell of tortoises on the Galapagos Islands. On islands with little low-lying vegetation the tortoises seem to have evolved long necks & limbs and different shell shapes which allow them to reach up more easily.
"The shell distortion and elongation of the limbs and neck in saddlebacks is probably an evolutionary compromise between the need for a small body size in dry conditions and a high vertical reach for dominance displays."
The following is multiple choice question (with options) to answer.
An example of camouflage is when an organism looks like what? | [
"clouds",
"local flora",
"buildings",
"oceans"
] | B | An example of camouflage is when an organism looks like its environment |
OpenBookQA | OpenBookQA-4732 | 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.
This animal is able to blend into its environment by changing its appearence | [
"an Elephant",
"a Bottlenose dolphin",
"a Phyllomimus",
"a Hammerhead shark"
] | C | An example of camouflage is when an organism looks like its environment |
OpenBookQA | OpenBookQA-4733 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
A cougar eats | [
"unwary dandelions",
"clouds",
"carrots",
"voles"
] | D | if an animal eats another animal then that animal is a carnivore or omnivore or predator |
OpenBookQA | OpenBookQA-4734 | thermodynamics, energy, power
Toyota Corolla, 13 gallon tank, 20% efficiency, 103 kWh usable energy
Tesla Roadster, 56 kWh battery capacity
Chevy Volt, 16 kWh battery capacity
If we compare a liquid Nitrogen car to the Chevy Volt it might not be so bad. But why would we do that? That car can still augment its range with gasoline. A part of the argument for electric cars is that you don't have the same energy loss from idling. Would that be true for a liquid Nitrogen car? There is no reason to believe that.
Let's say we assume a reasonable efficiency of half the isothermal process, which is illustrated in Figure 2 of the reference. Let's also say we'll hold 50 kWh of usable energy in the tank (even though this could still cause range problems). We've increased the tank size by a factor of 4 and the weight of the full tank is now around $1000 kg$. This is close to what many cars weigh.
The energy content relative to gasoline, as well as the alternatives, kills the idea. It would seem to require extremely optimistic assumptions to make it a reasonable proposal before we even get into the discussion about infrastructure needed to make it happen. The most fair comparison would be to other cars that also use alternative fuels, but it fails there too. EVs seem to have better viability on the basis of simple energetics. Maybe you're concerned that we'll run out of Lithium. A vehicle powered by compressed natural gas (not even the super-high pressure tanks that many have hope in) would blow it away, and the tank would be more manageable. Plus the fuel would be (dramatically) cheaper. Plus the infrastructure would be there. Plus, the engine is a proven design. We could do better with coal-to-liquids, we could probably do better with biofuels.
The following is multiple choice question (with options) to answer.
People are switching to electric cars because cars that use gas | [
"dirty the air",
"cry",
"nothing",
"cleans the air"
] | A | electricity causes less pollution than gasoline |
OpenBookQA | OpenBookQA-4735 | thermodynamics, energy, power
Toyota Corolla, 13 gallon tank, 20% efficiency, 103 kWh usable energy
Tesla Roadster, 56 kWh battery capacity
Chevy Volt, 16 kWh battery capacity
If we compare a liquid Nitrogen car to the Chevy Volt it might not be so bad. But why would we do that? That car can still augment its range with gasoline. A part of the argument for electric cars is that you don't have the same energy loss from idling. Would that be true for a liquid Nitrogen car? There is no reason to believe that.
Let's say we assume a reasonable efficiency of half the isothermal process, which is illustrated in Figure 2 of the reference. Let's also say we'll hold 50 kWh of usable energy in the tank (even though this could still cause range problems). We've increased the tank size by a factor of 4 and the weight of the full tank is now around $1000 kg$. This is close to what many cars weigh.
The energy content relative to gasoline, as well as the alternatives, kills the idea. It would seem to require extremely optimistic assumptions to make it a reasonable proposal before we even get into the discussion about infrastructure needed to make it happen. The most fair comparison would be to other cars that also use alternative fuels, but it fails there too. EVs seem to have better viability on the basis of simple energetics. Maybe you're concerned that we'll run out of Lithium. A vehicle powered by compressed natural gas (not even the super-high pressure tanks that many have hope in) would blow it away, and the tank would be more manageable. Plus the fuel would be (dramatically) cheaper. Plus the infrastructure would be there. Plus, the engine is a proven design. We could do better with coal-to-liquids, we could probably do better with biofuels.
The following is multiple choice question (with options) to answer.
Why are electric cars better for the atmosphere than traditional cars? | [
"they have Bluetooth",
"more breathable air",
"they go faster",
"they are bigger"
] | B | electricity causes less pollution than gasoline |
OpenBookQA | OpenBookQA-4736 | herpetology, poison
Title: Poisonous Snakes consuming poison (chemical) While travelling with my Son to a religious shrine, we saw a dead snake lying on the road.
My Son asked a curious question to me "Dad, if Poisonous snakes consume poison (Chemical), Will they die"?
I feel the answer is depends upon the type of poisonous snake viz Cobra, Python etc and how much the reptile has consumed the poison. i.e. quantity.
What is the correct answer? If any living thing consumes enough of a poison it will die. But I feel that is not what you want to ask.
Perhaps you meant to ask if a snake will die if it drinks its own venom? That would make more sense as a question.
In English, venom and poison mean different things when talking about a toxic chemical produced by an animal.
Poison is a toxic chemical produced by an animal that is meant to be ingested/eat/drink.
Venom is a toxic chemical produced by an animal that is meant to be injected into the bloodstream.
So a snake bite has venom, but a colourful tree frog has poison on its skin.
Venom is typically not nearly as harmful if ingested, even if by a different animal, because it is meant to act directly in the bloodstream
The following is multiple choice question (with options) to answer.
Poison causes harm to what things? | [
"vibrant",
"mineral",
"dead",
"decaying"
] | A | poison causes harm to living things |
OpenBookQA | OpenBookQA-4737 | herpetology, poison
Title: Poisonous Snakes consuming poison (chemical) While travelling with my Son to a religious shrine, we saw a dead snake lying on the road.
My Son asked a curious question to me "Dad, if Poisonous snakes consume poison (Chemical), Will they die"?
I feel the answer is depends upon the type of poisonous snake viz Cobra, Python etc and how much the reptile has consumed the poison. i.e. quantity.
What is the correct answer? If any living thing consumes enough of a poison it will die. But I feel that is not what you want to ask.
Perhaps you meant to ask if a snake will die if it drinks its own venom? That would make more sense as a question.
In English, venom and poison mean different things when talking about a toxic chemical produced by an animal.
Poison is a toxic chemical produced by an animal that is meant to be ingested/eat/drink.
Venom is a toxic chemical produced by an animal that is meant to be injected into the bloodstream.
So a snake bite has venom, but a colourful tree frog has poison on its skin.
Venom is typically not nearly as harmful if ingested, even if by a different animal, because it is meant to act directly in the bloodstream
The following is multiple choice question (with options) to answer.
If a person dies from a snake bite, the person was probably bitten by a | [
"bull snake",
"python",
"black mamba",
"boa."
] | C | poison causes harm to living things |
OpenBookQA | OpenBookQA-4738 | 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 lion with bones protruding from underneath its fur has been | [
"in a wardrobe",
"overfed",
"animated",
"underfed"
] | D | as the amount of food an animal eats decreases , that organism will become thinner |
OpenBookQA | OpenBookQA-4739 | biochemistry
Specific Force Deficit in Skeletal Muscles of Old Rats Is Partially
Explained by the Existence of Denervated Muscle Fibers
Association of adiponectin and resistin with adipose tissue
compartments, insulin resistance and dyslipidaemia
Shifts in the Distribution of Mass Densities Is a Signature of
Caloric Restriction in Caenorhabditis elegans
The following is multiple choice question (with options) to answer.
If your dog is getting noticeably skinnier, you need to | [
"increase its food intake",
"play some video games",
"feed it less food",
"Make it fly away"
] | A | as the amount of food an animal eats decreases , that organism will become thinner |
OpenBookQA | OpenBookQA-4740 | 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.
Dead organisms are the source of what for decomposers? | [
"nutriment",
"pride",
"oceans",
"people"
] | A | dead organisms are the source of nutrients for decomposers |
OpenBookQA | OpenBookQA-4741 | quantum-mechanics, operators, quantum-information, quantum-computer, linear-algebra
For a given $x\in\mathcal H$, the decomposition in (2) is given by $x = u + v$ where $u = P(x)$ and $v = x-P(x)$. Note that $U=Ran(P)$ and $V=Ker(P)$.
The following is multiple choice question (with options) to answer.
What is decomposed in decomposition? | [
"living creatures",
"lifeless life forms",
"plastics",
"metals"
] | B | dead organisms are the source of nutrients for decomposers |
OpenBookQA | OpenBookQA-4742 | thermodynamics, temperature, everyday-life, phase-transition, humidity
Title: Steam from a cup of coffee I observed that, in winter there is more visible steam from a cup of coffee than in summer. Is there any phenomenon taking place here. The amount of water that air can take up before the water creates fog or visible steam depends on temperature. The colder the air, the less water it needs to create fog/steam. It is the same principle when hot air rises, for example when pushed up a mountain and then it starts to cool down drastically --> It will rain.
For more have a look at: Relative humidity in https://en.wikipedia.org/wiki/Humidity
The following is multiple choice question (with options) to answer.
When is fog most likely to occur | [
"3 p.m.",
"midnight",
"6 p.m.",
"noon"
] | B | fog is formed by water vapor condensing in the air |
OpenBookQA | OpenBookQA-4743 | waves, acoustics, atmospheric-science, weather
Even with the question of attenuation - when visibility is reduced to 40 ft, echolocation will probably beat it handsomely at intermediate distances. There are a couple of other interesting things you can do to improve your ability to see in fog.
1) Yellow "driving glasses". These work because they cut out the blue components of light. When fog droplets are very small, light scattering is in the Rayleigh regime - that is, scatter probability goes as the inverse fourth power of the wavelength, and blue (400 nm) light is 16x more scattered than red (800 nm) [note - using round numbers...]. By cutting out the blue component, you reduce the amount of scatter that reaches the eye and improve the contrast. Skiers also use yellow "fog glasses".
2) Scanning light source. This is one of those magical things that ought not to work but does. With normal (flood) illumination, light scatters "from everywhere to everywhere". If instead you look along the line of (say) a laser shining into the fog, then the only scattered light you see is the light that scatters exactly 180 degrees back at you - which is a small fraction of all the scattered light. If you scan the light source and detection system in sync, and very quickly, you can build up an "almost scatter free" image. This raster scanning technology is used in some underwater search applications and can penetrate about 6 "attenuation lengths". As was discussed in the comments, this method actually works best when the viewing angle is not exactly 180 degrees - not only is the back scatter from the fog weaker (there is a curious doubling of scatter intensity that happens at exactly 180) but also, by looking at a slight angle, you are able to eliminate the back scatter from the closest fog - greatly improving penetration.
More recently researchers in Israel have come up with a way to image through thin layers of scattering material - as you can see in the link, they are also able to see "through fog" (although it was not clear to me whether their technique can apply to actual imaging in fog).
The following is multiple choice question (with options) to answer.
It's too foggy to see more than two feet on a highway. This is because of | [
"ash from a volcano",
"vapor of H2O condensed in the air",
"helium vapor in the air",
"a forest fire nearby"
] | B | fog is formed by water vapor condensing in the air |
OpenBookQA | OpenBookQA-4744 | newtonian-mechanics, drag, relative-motion
Title: Relative motion-Acceleration My first post here and I'm a complete beginner on this. So please excuse if I'm asking too-basic a question. This question is about the classical boat and river problem.
Say a boat travels at 10 m/s in a water channel.
the water speed relative to ground is 0.
so the boat travels at 10 m/s relative to the ground.
now suddenly, the water in the channel has started to flow at 10 m/s in the opposite direction. (say this happened in 10 seconds so the acceleration is 1 m/s^2).
As after a while the boat speed relative to ground has become 0,
then from the ground-based observer's point of view, the boat has undergone a deceleration.
My question is;
Is this deceleration always necessarily equal to minus the water acceleration?
In other words whats the velocity of the boat with respect to the ground, infinitesimal time dt after the water has started to accelerate ?
PS: What I'm trying to understand is what happens when an aircraft or watercraft gets hit by a gust or similar disturbance?
My question is; Is this deceleration always necessarily equal to minus the water acceleration?
The answer is no. Acceleration/deceleration is controlled by the fluid-resistance $f$. Typically:
$$f=kv\qquad \text{ for low speed}\\
f=kv^2\qquad \text{ for high speed}$$
where $v$ is speed of the object (boat, airplane, car ...) relative to the fluid and $k$ a coefficient.
The following is multiple choice question (with options) to answer.
As an airboat moves from grass to water it will | [
"blow up",
"sink",
"speed up",
"slow down"
] | C | as the smoothness of something increases , the friction of that something will decrease when its surface moves against another surface |
OpenBookQA | OpenBookQA-4745 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
A cat and a snake are both predators for several of the same animals. If there are only seven mice in a habitat shared by a cat and a snake, there will be | [
"a shared meal between them",
"a war between mice and cats",
"pressure on them to get the mice before the other does",
"enough for each of them to have ten mice"
] | C | if two animals have the same food source then those two animals compete for food |
OpenBookQA | OpenBookQA-4746 | Best Japanese Brown Rice, Air Fryer Burgers And Fries, østfold University College Vacancies, Band T-shirts Walmart, How To Become An Anglican Priest, Too Much Fennel Taste, Porter Cable Circular Saw Cordless, Utmb My Chart, Iams Large Breed Dog Food Nutrition Facts,
The following is multiple choice question (with options) to answer.
Which are in opposition for similar chow? | [
"cats and mice",
"dogs and sycamores",
"bears and salmon",
"lions and hyenas"
] | D | if two animals have the same food source then those two animals compete for food |
OpenBookQA | OpenBookQA-4747 | meteorology, snow, radar
Also note that winter precipitation adds an extra complication because the particles are lighter in weight and can thus be blown about more by vertical and horizontal winds. Raindrops (and hail) are quite likely to fall unless extreme updrafts exist because they are heavy. But drizzle, snow, and sleet may be blown around quite a bit. Without a time-intensive dual-Doppler analysis, you cannot know the wind motion in the storm thoroughly, and therefore will have varying results at times.
And finally, the big wrench is unfortunate inherent to how radars work. They measure the percentage of their sent energy that is reflected back to them. That's great because that's directly connected to the diameter of the item falling (to the 6th power). But unfortunately the grand problem is that in a storm, there is a huge variety of drop/flake sizes mixed together at once... such that we can't extract which combination of particle sizes created it (and thus can't calculate volume to actually know the rain/snow amount that falls). It could be like 6 medium size flakes causing the 10 dBZ echo... or 2 large flakes and 10 small flakes... and each combination is a different volume/snow total. (to see the nitty-gritty math details on this, read more here.) So we can never know for sure the exact rain/snow falling using just radar. The good news is we've at least done lots of experiments and come up with some fairly useful best-practice formulas for using the Z-R ratio in different scenarios. Good, but not perfect.
The following is multiple choice question (with options) to answer.
Snowy means a large amount of what? | [
"roads",
"rivers",
"ice particles",
"winds"
] | C | snowy means a large amount of snow |
OpenBookQA | OpenBookQA-4748 | forces, air, coriolis-effect
Title: Does Coriolis effect affect snowing? Right now, outside is snowing. No matter what window I look from, the snow constantly for last few hours tends to fall to the right close to the window, and to the left close to the building across the street, just like it would suggest the Coriolis effect on northern hemisphere.
I understand the Coriolis effect applies for air flow and the reasons for this may be in something completely different, specific to the street I am in. But in theory - could the Coriolis effect on snowing be so dramatic, it would be observable?
could the Coriolis effect on snowing be so dramatic...?
No. The Coriolis effect is only noticeable for objects traveling long distances with respect to Earth's surface for significant periods of time. For example, a ballistic missile fired hundreds of miles or a hurricaine that is hundreds of miles in diameter and lasts for days. Across the street is too small a distance for an noticeable effect.
The Rossby Number can be used to determine if the Coriolis effect is significant in a given situation.
Another way of thinking of it is: the Earth only rotates once a day, how does the phenomenon being investigated compare to this fact?
The following is multiple choice question (with options) to answer.
If you hear that its snowy outside, you can expect there to be | [
"an abundance of fire",
"Absolutely zero snow outside",
"a plethora of snow",
"frogs falling from sky"
] | C | snowy means a large amount of snow |
OpenBookQA | OpenBookQA-4749 | geology, rocks, sedimentology, geomorphology, terminology
Title: What do you call boulders of non sedimentary rock that were lithified into sandstone? I'm convinced there is a word for this. I was in the Hoodoos at Writing on Stone this weekend and kept noticing what looked like reddish quartzite boulders laying around in the sand, or sometimes sticking partially out of the hoodoos.
When a non-sedimentary rock gets washed out into silt which later lithifies, what's it called? It's kind of like a conglomerate, except there's only a couple of really big rocks, which eventually fall out out the rock because all the sandstone around them eroded away. The technical term for a sedimentary rock that has a lithified fine-grained sediment with larger pieces of rocks suspended in it upon lithification is a conglomerate. The fine-grained interstitial part is called the matrix, and the large pieces suspended in it are called clasts. Clasts can range from gravel- to boulder-size. These are technical terms used by sedimentologists.
It is tempting to refer to these fragments as xenoliths but as that word has a very specific meaning in igneous petrology, it is best to avoid it to remove any confusion.
The following is multiple choice question (with options) to answer.
If a rock is sedimentary then | [
"sediment was fused with lava",
"sediment was packed into tummies",
"sediment was watered with salt",
"sediment was packed tightly"
] | D | sedimentary rocks are formed from sediment compacting together |
OpenBookQA | OpenBookQA-4750 | geology, rocks, mineralogy
Title: What is this Lake Michigan rock? Rock found along northern Lake Michigan, (Charlevoix, MI). Made up of very thin crystalline layers. There are small, round bubble like bumps that protrude from the surface. Doesn't show well in the picture, but the rock has a sugary appearance. I can't be definite but my three best guesses are Travertine, Agate and maybe Halite, if it fizzes in mild acid it's Travertine, a form of Limestone, if it dissolves in hot water it's Halite, or Rocksalt, otherwise if it's more or less inert it's probably Agate, an amorphous silicate. I find Halite unlikely, the other two are probably pretty equally likely in that location.
The following is multiple choice question (with options) to answer.
At the beach you are likely to find this type of stone: | [
"rock that is compacted from other rock",
"rock that is formed of plastic",
"rock that is formed of water",
"rock that is compacted trash"
] | A | sedimentary rocks are formed from sediment compacting together |
OpenBookQA | OpenBookQA-4751 | botany, ecology, energy
Title: Why do plants create enough energy for the entire ecosystem? In my environmental class, we were recently learning about the $10\%$ law that basically says only $10\%$ of the energy goes from one trophic level to the next.
This got me thinking about why energy flows from one level to the next. Specifically, why do plants create enough energy for the entire ecosystem? Wouldn't they do fine without us, and wouldn't that save them the work of creating all that excess energy? Plants collect energy for themselves via photosynthesis, not for others.
It is used for it's own growth and survival.
It's energy is then redistributed to other organisms when either the plant dies and decomposes or when it is consumed. Many organism cannot collect their energy like plants do, and thus must feed on organisms (like plants) that are able to collect and store energy. This is in many cases detrimental to the plant (it should be intuitive why being eaten might be bad), and many, many plants do have traits to discourage other organisms from eating them (plants with toxins, thorns, etc.).
The following is multiple choice question (with options) to answer.
If a plant is being nourished throughout all of itself, the reason is most likely | [
"plastic tubes",
"internal tubes",
"interior walls",
"metal tubes"
] | B | phloem transports materials through the plant |
OpenBookQA | OpenBookQA-4752 | species-identification
Title: What is this (water-loving) bug? For some time we've been finding these little fellows in our apartment:
They seem harmless enough, but finding them is a bit... annoying. I found the fellow above in the bathtub, and it's not uncommon to find more than one.
Unfortunately, some started to appear near the kitchen sink as well. Or outside of the bathroom on the floor (at least that's where we noticed them).
I think this thing prefers darkness over light, and seems to be drawn towards wet places or just water. These critters are also surprisingly fast.
What is it? Should we be concerned about a pest problem, or is this just a minor, unwelcome guest?
PS. We live in Poland. It is a Lepisma saccharina or silverfish.
It is rather common and yes, it's harmless.
The following is multiple choice question (with options) to answer.
Some humans live in what? | [
"lakes",
"trees",
"oceans",
"homes"
] | D | some humans live in houses |
OpenBookQA | OpenBookQA-4753 | everyday-life, biophysics
Title: What's Optimal About Six Legs According to Physical Laws? In many respects the insects can be regarded as the most successful class of animals in evolutionary terms. And one of the most common features of insects is that they (mostly) all have six legs.
Not discounting other traits, is there something about six legs that has helped insects achieve this success?
Can we use physical laws to analyze and determine an optimality of having six legs - perhaps such as stability? I can think of two possible reasons: first, you can have half your legs up in the air at one time (as in walking - two on one side and one on the other, then change) and still be perfectly stable (3 legs = most stable, like a tripod); and second, if a predator chews off a leg on either side, you still have two legs (so you can still walk). I think those arguments are borderline biomechanical, rather than physical...
The first argument has some solid scientific backing - see for example http://web.neurobio.arizona.edu/gronenberg/nrsc581/powerpoint%20pdfs/cpg.pdf . It doesn't take a lot of brains to walk with six legs... I fact it can be done almost entirely with "local" neurons. That's a good thing when you don't have a lot of brains.
Quoting from https://answers.yahoo.com/question/index?qid=20090418111020AA75mgR :
Generalizing, insects walk with a metachronal gait and, with speed, a tripod gait - which involves a tripod stance - 2 legs on one side of the body and one on the other remain stationary while the other legs move forward, then the stationary legs walk as the others take a stance. In this way, walking involves maximum stability with a minimum of neural coordination. In fact, ganglia and other nerves and sensors located on each leg may contribute as much to the actual walking movement as the brain does. It's a very easy, stable and adaptable locomotory system which evolved from the basic arthropod body plan with 2 pairs of limbs on each body segment.
The following is multiple choice question (with options) to answer.
If a biped which uses tools is in an ideal habitat, there will be within it | [
"sharks",
"glaciers",
"potholes",
"rooms"
] | D | some humans live in houses |
OpenBookQA | OpenBookQA-4754 | food-chemistry
popcorn (kernels)
honey (jar of)
sugar (most forms)
alcohol (spirits like vodka, whiskey)
dried beans, dried lentils
I would not be planning to eat any of these stored for 25 years myself. And in general I'd suggest testing the items before trying them after 25 years or more (if you feel you must).
I would not expect cans or glass or plastic bottles of soda to be in good shape after anything like 25 years. The plastic might not survive without degrading. The can and plastic might react with the liquid over that timescale and the glass would survive but I'd be less optimistic about a sugar laced chemical soup like soda or cola not undergoing some changes. Hard to say.
If you want more info on this try this website.
Will it be ok to drink it, if it won't explode?
I would not try it. At best it soda would be flat and possibly not taste the same (chemical changes over that timescale ?) and at worst it could actually be harmful.
Exploding seems very unlikely.
Also, what about Snickers or a hamburger in a ziploc package with air sucked out of it with vacuum cleaner?
Air isn't the issue. There are bacteria that will happily live (and increase in numbers) on what's in the food. Well, it is food, after all. There are bacteria that will survive refrigeration as well. Over the timescale you're talking about I'd say it's all bets are off territory.
So: will Snickers, Hamburger in a ziploc, Bottle (or can) of Cola, all not opened, go crazy in 25 years? In 50 years?
All of those could be dangerous over such a long time period, IMO. At the very least they'd taste bad and at worst they'd kill you if you consumed them.
If so, can they go out of their packages and ruin the contents of the time capsule? If not, will it be safe to consume one of them?
Depends on the packaging. Glass would last indefinitely baring physical force or extreme of hot and cold (which might possibly cause fatigue cracking). The other wrappers would last pretty well (structurally), but 25 years is way past their design intentions. It would be a dice throw.
The following is multiple choice question (with options) to answer.
Consuming from an aluminium container, a human is likely enjoying | [
"a melted down liver enzyme",
"a strange liquid metal",
"a makeshift type of pasta",
"a crisp beverage with cold bubbles streaming throughout it"
] | D | a soda can is made of aluminum |
OpenBookQA | OpenBookQA-4755 | energy-conservation, electrical-resistance, potential-energy, capacitance, dissipation
Title: Is the overall energy conserved in this situation? Imagine a fully charged capacitor.
This will create an electric field, and if a fixed charged particle is nearby, it will possess some amount of electric potential energy.
But what happens to the potential energy if one discharges the capacitor?
The potential energy must be converted into other forms of energy, but I can't understand how. If totally discharged the energy will have been dissipated as heat in cicuit resistance. If partially discharged, part of the energy is dissipated as heat, part stored somewhere else in the circuit, and part retained by the capacitor. In all cases the total energy is conserved.
All circuits have resistance (except supercooled conductors) so when a capacitor discharges at least part of its potential energy is dissipated as resistance heating. If the circuit consists only of resistance, all the energy will be dissipated as heat.
But if there’s other energy storage devices in the circuit some of the discharge energy can be stored in those devices. For example if there are other capacitors in the discharging circuit some of the discharge energy can be stored as electrical potential energy in those other capacitors. If there are rechargeable batteries in the circuit, part of the discharged energy may be stored as chemical potential energy in the batteries. The same would apply to any other electrical energy storage devices.
The above neglects a small amount of electromagnetic energy that may be radiated away from the circuit.
Hope this helps.
The following is multiple choice question (with options) to answer.
This is most likely to be conserved: | [
"CO2",
"toilet paper",
"a soda can",
"styrofoam"
] | C | a soda can is made of aluminum |
OpenBookQA | OpenBookQA-4756 | automotive-engineering
Title: What's so special about Tesla's all-electric automobiles, compared to other car manufacturers'?
Why haven't car manufacturers caught up with Tesla's automobiles?
E.g. why haven't the Chevy Bolt, Nissan Leaf, VW e-Golf driven (pun intended) TSLA out of business?
I list TSLA's advantages that don't appear grueling or covert or confidential to mimic, like its exterior appearance. Yet u/skogoa wrote that "Tesla is very good at marketing. Their technology isn't all that special but they have managed to build quite a lot of hype."
i_start_fires. 62 points 5 years ago
Well, they're the only company producing cars that can run 250+ miles on electric power alone. They are single-handedly building a network of charging stations in the US making cross-country electric travel a viable reality for the first time. They recently released their entire patent portfolio into the public domain, allowing any company to use their electric car, battery, and charger designs for free.
Turtlecupcakes. Aug 25 2013.
Their range nearly competes with gas (2-300 miles, I believe)
They look like high-end vehicles, not some pile of plastic that runs on batteries.
The entire in-car dashboard and computer system is built from the ground up so that software can control nearly every single motor, display, relay, and so on. This means that all sorts of functionality can be added at any point through firmware updates. Most existing car manufacturers just build new cars on the old computer systems that were basically hardwired to perform specific function. (So even though the AC is digitally controlled, the only way to change its behavior is to basically take the car apart, pull out the microcontroller, and reprogram it.)
NiceTryNSA. 26 points. Aug 26 2013.
The following is multiple choice question (with options) to answer.
Electric cars can have _______ and still run | [
"feelings",
"digestive tracts",
"empty juice",
"hairy bodies"
] | C | an electric car uses less gasoline than a regular car |
OpenBookQA | OpenBookQA-4757 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
Which would be most useful in determining an areas climate? | [
"Average daily temperatures for five years",
"A flood report from three years ago",
"Last year's rainfall totals",
"A report of a tornado"
] | A | climate is the usual kind of weather in a location |
OpenBookQA | OpenBookQA-4758 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
The usual kind of weather in a location is called what? | [
"warmth",
"fog",
"zone conditions",
"visibility"
] | C | climate is the usual kind of weather in a location |
OpenBookQA | OpenBookQA-4759 | electric-circuits, potential, electrical-resistance, conductors
These analogies are not exact and are only intended to give you a better feel as to what is happening.
Hope this helps.
The following is multiple choice question (with options) to answer.
An example of an electrical conductor could be | [
"wood",
"ice",
"coin",
"rubber"
] | C | An electrical conductor is a vehicle for the flow of electricity |
OpenBookQA | OpenBookQA-4760 | power-engineering, inductive-charging
Title: Efficiency of wireless charging for moving cars The UK is about to start trials of wireless charging for moving cars.
What kind of power transfer efficiency is likely to be achievable in such a system, compared to just plugging in the car directly? This is not exactly a comprehensive answer, but I found an interesting article on The Institution of Engineering and Technology's website. It is fairly interesting, if not incredibly technically detailed, and I encourage you to check it out for projects to learn more about. I'll talk about the most interesting parts here.
It has many interesting projects listed. Some are for bus routes, and rather than charging along the whole route, they use 'opportunistic charging' to charge at key places (presumably bus stops and traffic lights) to rapidly transfer energy. This is intended to minimize the disruption and possibly cost of construction (imagine having to dig up an entire busy road to add charging coils). This is called "semi-dynamic charging" by Transport Scotland, who are working on one such project.
However, it sounds like in Korea, a more full route system has been operating.
[T]he Korea Advanced Institute of Science and Technology (KAIST) is running two online electric vehicle (OLEV) buses on a 12km continuous charging route in the city of Gumi. It claims 85 per cent maximum efficiency in power transfer.
You're question is focused on the pure efficiency of the charging capacity, but I think also interesting to consider (or possibly implied in the question) is for what cases these technological limitations make actual use a practical exercise. On that note, I will add that this technology may prove of more usefulness on highways, where range is of particular concern in the arena of electric vehicles, leading to projects going to great lengths to provide very close charging stations (25 to 50 miles) like West Coast Green Highway.
The following is multiple choice question (with options) to answer.
What is a vehicle for the flow of electricity? | [
"a metal sword",
"a wooden chair",
"a plastic ring",
"a dry towel"
] | A | An electrical conductor is a vehicle for the flow of electricity |
OpenBookQA | OpenBookQA-4761 | # Help me understand events/sample space
## Homework Statement
1.
Suppose that A, B, and C are 3 independent events such that Pr(A)=1/4, Pr(B)=1/3 and Pr(C)=1/2.
a. Determine the probability that none of these events will occur.
Is it just:
(1-P(a))(1-P(b))(1-P(c)) = 3/4 * 2/3 * 1/2 = 1/4
## The Attempt at a Solution
I tried to do 1. another way:
The probability that all theses events will occur: 1/4 * 1/3 * 1/2 = 1/24
1-(1/24) = 23/24
Obviously this is wrong. Is the reason it is wrong, because: the complement of "all of these events will occur" is that "not all of these events will occur," meaning, it is not "none of these events will occur."
None of these events will occur is included in the compliment 1-(1/24), but so is that 1 of the events occur, and that 2 of the events occur, etc.
Am I right in my reasoning?
PeroK
the (1) is correct.
for reference, in general the answer can be found by calculating multinomial distribution.
in (3), the 23/24 probability is sum of "no events", "A only", "B only", "C only", "A&B", "A&C", "B&C".
PeroK
Homework Helper
Gold Member
2020 Award
## Homework Statement
1.
Suppose that A, B, and C are 3 independent events such that Pr(A)=1/4, Pr(B)=1/3 and Pr(C)=1/2.
a. Determine the probability that none of these events will occur.
Is it just:
(1-P(a))(1-P(b))(1-P(c)) = 3/4 * 2/3 * 1/2 = 1/4
## The Attempt at a Solution
I tried to do 1. another way:
The probability that all theses events will occur: 1/4 * 1/3 * 1/2 = 1/24
The following is multiple choice question (with options) to answer.
Which three events are likely to occur once per day? | [
"3 cycles of day, 3 cycles of night, and birds chirping as the sun rises",
"a cycle of day, a cycle of night, and a motorcycle",
"a cycle of day, a cycle of night, and birds chirping as the sun rises",
"a cycle of day, a cycle of night, and birds flying"
] | C | cycles of day and night occur once per day |
OpenBookQA | OpenBookQA-4762 | biochemistry, biophysics, cell-membrane, literature
Title: How does membrane potential vary between intraceullar membranes and the cellular membrane? Question
Does each type of membrane have a different membrane potential? I'm especially interested in answers that can cite academic papers that have attempted to measure membrane potentials.
Discussion
I've asked about the composition of membranes before , and although I recieved some information, I didn't get all the information I was after. This isn't a problem with our community but rather with the field at large: the popular thinking is membranes are membranes are membranes (mostly due to the difficulties in studying membrane biophysics experimentally).
This is how wikipedia defines membrane potential:
Membrane potential (also transmembrane potential or membrane voltage)
is the difference in electric potential between the interior and the
exterior of a biological cell. - Wikipedia
This isn't strictly true. Intracellular membranes also have membrane potentials as one can imagine, and there is some unverified information regarding compartmental pH values. This is why I am interested to find out if there have been studies attempting to quantify this across the cell membrane, and across different subcellular membranes. Yes, various intracellular membranes do have potential differences, but as you can imagine they are more difficult to measure experimentally, so in general data on this is scarce.
Summary
Mitochondrial membrane: 150mV-180mV with negativity on the matrix side. Seth et al 2011
Endoplasmic reticulum membrane: 75-95mV with negativity in the ER. Qin et al 2011, Worley et al 1994
Golgi: No notable membrane potential. Schapiro & Grinstein 2000
Lysosomal: 20mV with more negativity on the cytosolic side. Koivusalo et al 2011
The following is multiple choice question (with options) to answer.
If something has a membrane within another thing, it is likely | [
"a marker",
"a dark hole",
"a house",
"able to cry"
] | D | the cell membrane provides support for a cell |
OpenBookQA | OpenBookQA-4763 | friction, statics
Title: Why is skidding considered kinetic friction when braking on a car? So according to my textbook applying the brakes hardly to essentially lock up the wheels causes skidding which is kinetic friction so the breaking distance is longer. However, if the brakes were "pumped" the card would not skid and it will be considered static friction so the braking distance is shorter. I UNDERSTAND that the coefficient of static friction has a greater magnitude than kinetic friction, so it makes sense as to why static has a greater deceleration and shorter brake distance. HOWEVER, I do not understand why skidding is considered kinetic friction and not static friction; and why "pumping" the brakes causes static friction. Can someone please explain to how they are so? Kinetic friction is all about trying to stop one surface from skidding against another surface. When you have two things such as the wheel and the ground sliding against each other, this is kinetic friction. However, when the wheels are rotating, there is static friction between the ground and the wheel. This is because the wheel is rolling and not sliding against the ground. A point on the wheel only contacts the ground for a very very small instant per revolution, so this is static because there isn't sliding between the ground and the wheel.
The following is multiple choice question (with options) to answer.
Skidding causes friction, as seen in | [
"rolling a car",
"riding a rhino",
"running a track",
"Nascar races"
] | D | skidding causes friction |
OpenBookQA | OpenBookQA-4764 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
Weathering is the eventual reason that | [
"ferns can have sustenance",
"lighthouse make visible light",
"dogs always eat homework",
"cats can hunt prey"
] | A | soil is formed by weathering |
OpenBookQA | OpenBookQA-4765 | mountains, rainfall
Title: Could a waterfall lashing onto a road lead to a landslide? Here is a video of a waterfall lashing on to a mountain road, with vehicles driving under it.
https://youtu.be/cHaguj--YBc
There appears to be a big hole carved out right next to the road, possibly by the force of the waterfall.
Is this a ticking time bomb for a landslide? Potentially, a landslide could occur. Whether it would be a minor slip or a major fall depends on the geological conditions at the site, the force of the water and the duration that the site is impacted by the water.
In the video in question, the rock face above the road appears competent, but there are not guarantees. The main issue would be is the water undermining the road which could cause a slip and the road to slide.
The more loose the geological material is, the easier it is to dislodge it. Once one item moves a chain of events can occur where additional items are dislodged and a slide occurs.
In addition to high pressure water dislodging material, water acts as a lubricant, making it easier for rocks and regolith to be dislodged.
To minimise the potential for a slide to occur in such a situation, the surface of the road would need to be sealed very well and a very good drainage system installed that would move the water away from the road and the slope below the road
The following is multiple choice question (with options) to answer.
A landslide may bring immense problems to | [
"living regions",
"time travel",
"space",
"Jupiter"
] | A | a landslide is when gravity rapidly moves rocks or soil downhill especially after a rain storm |
OpenBookQA | OpenBookQA-4766 | electricity, electric-circuits, electrons
Title: Do electrons coming out of a lightbulb (and going back into the circuit) slow down? Do electrons coming out of a lightbulb (and going back into the circuit) slow down?
The electrons enter the light bulb filament with relatively high kinetic energies. As they travel through the filament they collide with metal atoms transferring much of their kinetic energy to the metal. This energy raises the temperature of the metal. The metal in turn radiates this energy as electromagnetic waves, many in the visible spectrum.(Source 1)
and
Each light bulb results in a loss of electric potential for the charge. This loss in electric potential corresponds to a loss of energy as the electrical energy is transformed by the light bulb into light energy and thermal energy. (Source 2)
The following is multiple choice question (with options) to answer.
Which is a byproduct of a lightbulb? | [
"taste",
"death",
"warmth",
"sound"
] | C | an incandescent light bulb converts electricity into heat by sending electricity through a filament |
OpenBookQA | OpenBookQA-4767 | asteroids, chicxulub, sound
So let us approach it the other way round: What is the loudest possible sound?
Strictly speaking, the loudest possible sound in air, is 194 dB. The “loudness” of the sound is dictated by how large the amplitude of the waves is compared to ambient air pressure. A sound of 194 dB has a pressure deviation of 101.325 kPa, which is ambient pressure at sea level, at 0 degrees Celsius (32 Fahrenheit). Essentially, at 194 dB, the waves are creating a complete vacuum between themselves.
You can go louder than 194 dB, but that’s not technically a “sound” anymore. The extra energy starts distorting the entire wave, and you end up with something that’s more a shockwave and less a soundwave. At that level, sounds don’t pass through air — they push the air along, producing pressurized burst (shockwaves).
On the shockwave of Chicxulub, I found the page at the Lunar and Planetary Institute insightful:
The Chicxulub Impact event produced a shock wave and air blast that radiated across the seas, over coastlines, and deep into the continental interior. Winds far in excess of 1000 kilometers per hour were possible near the impact site, although they decreased with distance from the impact site. The pressure pulse and winds would have scoured soils and shredded vegetation and any animals living in nearby ecosystems. An initial estimate of the area damaged by an air blast was a radius 1500 kilometers. There are several factors that can affect this estimate, so the uncertainty might be better reflected in a range of radii from ~900 to ~1800 km. The travel times are quite short, so this effect would have occurred in advance of any falling debris ejected from the Chicxulub crater.
Equipped with all this, we can now try to answer "How loud was the Chixculub explosion?" even if you did not specify where you measure loudness: At the radius of $\approx 1\,500 {\rm km}$ from the epicenter, the shockwaves "fades" out to become the loudest possible sound of 194dB.
The following is multiple choice question (with options) to answer.
Which is loudest? | [
"a soft kiss",
"a flea fart",
"a whisper",
"a motor"
] | D | matter vibrating can cause sound |
OpenBookQA | OpenBookQA-4768 | organic-chemistry, alcohols, organophosphorus-compounds
Animal studies are consistent in reporting a decrease in the body weight of rats receiving ethanol solutions as the only source of liquids. Concentrations of ethanol as low as 5% (v/v), which are similar to the ethanol content of a Brazilian beer, or as high as 40% (v/v), solution similar to spirit drinks, are related to decreased body weight gain (9). Similar results have been reported for 20% (v/v) ethanol solution (10).
Different results have been obtained for malnourished animals. Da-Silva et al. (11), studying rats which had been treated with ethanol for 90 days, reported a significant weight gain by malnourished rats (50% food restriction) drinking a 20% (v/v) ethanol solution when compared to malnourished rats drinking water. A more recent study (12) reported improvement in somatic and motor development and a decrease in the mortality rate of the offspring of malnourished rats drinking low doses of ethanol (5%, v/v). These data suggest that malnourished rats can benefit from ethanol calories.
In summary, in spite of the large number of studies on the effects of ethanol in well-nourished animals and humans, there is still controversy about how well ethanol-derived calories can be utilized. Fewer studies are available about special physiological conditions such as malnutrition. Over the last few years, scientific research has mainly focused on obesity, an increasing problem in developed countries, which led us to the false belief that malnutrition was no longer a problem worth investigating. However, there are still 800 million malnourished people in the world (13). The decreasing interest of the scientific community in problems related to malnutrition has left many questions without an answer. Ethanol consumption and its consequences on the malnourished organism are among them.
In view of the importance of malnutrition in Brazil - 22% of the population or 40 million people are malnourished (14), as well as ethanol consumption and alcoholism - 11% of Brazilian population are alcoholics (15), the aim of the present study was to assess the use of ethanol calories in a dose/effect model by evaluating body weight before and after the installation of malnutrition.
The following is multiple choice question (with options) to answer.
Food is less risky to consume when | [
"spoiled",
"fully cooked",
"defecated on",
"rotted"
] | B | reducing bacteria in food prevents illness in people |
OpenBookQA | OpenBookQA-4769 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
Illness is prevented in people by reducing what in food? | [
"fiber",
"dangerous bugs",
"protein",
"fat"
] | B | reducing bacteria in food prevents illness in people |
OpenBookQA | OpenBookQA-4770 | python, beginner, python-3.x
while True:
self.fertilizer = int(input("Please enter the amount of fertilizer (scale 0-10): "))
if self.fertilizer not in range(11):
print("***NOT A VALID AMOUNT***")
continue
if self.fertilizer == self.Plants.preferred_fertilizer:
self.fertilizer_score = 10
break
elif self.Plants.preferred_fertilizer - 2 <= self.fertilizer <= self.Plants.preferred_fertilizer + 2:
self.fertilizer_score = 7
break
else:
self.fertilizer_score = 4
break
# Automated weed removal: random score
count = 0
while self.weed == True:
x = 1* random.random()
count += 1
if x < 0.3:
self.weed == False
print("You have removed the weeds", count, "times to help the plant grow. Good job!\n")
break
if count <= 3:
self.weed_score = 10
else:
self.weed_score = 5
# Calculate probability of fruit growth. Weight of parameters: water 30%, fertilizer 30%, soil type 10%, - user selection
# weed 20%, temperature 10% - random
self.probability = 0
if self.Environment.soil_type == self.Plants.preferred_soil:
self.probability += random.uniform(0.7, 0.9) * 0.1
else:
self.probability += random.uniform(0.3, 0.5) * 0.1
if self.Environment.temp_return == self.Plants.preferred_temp:
self.probability += random.uniform(0.7, 0.9) * 0.1
else:
self.probability += random.uniform(0.3, 0.5) * 0.1
The following is multiple choice question (with options) to answer.
A farmer is getting a worse crop yield every year, what method might be causing this? | [
"Switching to Sustainable Farming",
"Growing nothing but corn",
"Raising Livestock and crops",
"Using Hydroponics in farming"
] | B | crop rotation has a positive impact on soil quality |
OpenBookQA | OpenBookQA-4771 | 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 traits could be pass along using reproduction and genetic material? | [
"habits.",
"money",
"nose",
"thoughts"
] | C | reproduction is a stage in the life cycle process |
OpenBookQA | OpenBookQA-4772 | evolution, taxonomy, phylogenetics, history
You could argue that a (dead) llama is a big animal, but one can describe an animal using just its bones, or even just some of its bones. Besides that, it's worth mentioning that Owen received a whole mammoth in UK to study and describe! So, sometimes, size is not a problem.
Answering your second and third questions, a good deal of the animals he described he never actually saw in the wild or alive. Estimating the precise fraction is way more complicated. The same may be said regarding plants, but I guess that the fraction here is smaller: live plants are easier to maintain, seeds are easy to be transported and sown etc. Besides that, botany was Linnaeus' area of expertise. The same link above says...
Linnaeus was also deeply involved with ways to make the Swedish economy more self-sufficient and less dependent on foreign trade, either by acclimatizing valuable plants to grow in Sweden, or by finding native substitutes. Unfortunately, Linnaeus's attempts to grow cacao, coffee, tea, bananas, rice, and mulberries proved unsuccessful in Sweden's cold climate. His attempts to boost the economy (and to prevent the famines that still struck Sweden at the time) by finding native Swedish plants that could be used as tea, coffee, flour, and fodder were also not generally successful.
... which shows us that he dealt with live exotic plants.
Regarding your fourth question ("did he name species based on other people description but without ever seeing one dead or alive?"), the answer is yes, specially for plants and insects: there are several specimens that Linnaeus described based just on drawings or paintings (which may be considered other people's description), without ever seeing the actual organism. Two examples are Dysdercus andreae (an animal) and Porella (a plant).
PS: Not related to this question or to biology, but this is (unfortunately) quite common in sciences: some of Freud's patients, among them his most famous cases (Anna O., little Hans, etc...), he never actually met or even saw at the distance! He "diagnosed" them using just descriptions and hearsay...
✻ According to RHA comment below, there is a third way: sending people to collect the specimens for you.
The following is multiple choice question (with options) to answer.
A creature that is lacking domestication, and is also lacking a wild space, perhaps occupies | [
"a wild time",
"a distant planet",
"a small crater",
"a displayed habitat"
] | D | some animals live in zoo exhibits |
OpenBookQA | OpenBookQA-4773 | Decide the seating order of the people, starting from one of the brothers, say Ivan. Then position the other brother, Alexei, in one of the two slots (fourth and fifth) that fulfill the "separated by two others" condition - $2$ options. Then with Ivan and Alexei resolved, order the remaining five people in one of $5!=120$ ways. Finally add the empty chair to the right of someone, $7$ options, giving $2\cdot 120\cdot 7 = 1680$ options.
$\underline{Get\;the\;bothersome\;empty\;chair\;out\;of\;the\;way\;\;as\;a\;marker\;at\;the\;12\;o'clock\;position}$
• Brother $A$ has $7$ choices of seats
• Brother $B$ now has only $2$ choices (one clockwise and one anticlockwise of $A$ )
• the rest can be permuted in $5!$ ways
• Thus $7\cdot2\cdot5!\;$ways
The following is multiple choice question (with options) to answer.
Some people have an | [
"tubs for skin",
"extra rib",
"snakes for hair",
"magic"
] | B | skeletal system is made of bones |
OpenBookQA | OpenBookQA-4774 | classical-mechanics
Finally, raw force is probably the dominant factor here. Pushing allows you to use the full strength of your muscle, which is probably somewhere around your weight (with a rather large spread). On the other hand, hitting allows you to accumulate the strength of your muscles over the duration of the swing, allowing you to impart much bigger forces than would be possible with just pushing. Try driving nails just by pushing the hammer, and you'll see the difference rather easily - the only benefit you'll get from using a hammer is that you're not going to feel as much pain as when pushing against the much smaller nail head.
The following is multiple choice question (with options) to answer.
Which of these is more likely to cause a fracture from swinging | [
"foam bat",
"steel wire",
"a mace",
"metal spoon"
] | C | skeletal system is made of bones |
OpenBookQA | OpenBookQA-4775 | theoretical-biology, hematology, red-blood-cell
**As an intern, I once had the very sorrowful experience of admitting an healthy appearing, exuberant 4 year old child to the pediatric surgical service. The only presenting symptom was that the child started squatting during exertion (not good), and on exam, had a murmur which was caused by aortic stenosis. This was long before imaging studies were as sophisticated as they are now. The pediatric cardiac surgeon took him to the operating room (OR) to replace the valve, but there was so much atherosclerotic aortic damage that there was no healthy tissue which could hold sutures in place. The child died in the OR. I don't know what would have been done today, but had the child stayed home, they might have had a couple more years with the parents, who hoped for an uneventful procedure. So the exercise involved in this answer was fun, but the memory it brought back is still quite sad.
The following is multiple choice question (with options) to answer.
A child will only grow if they are provided with | [
"energy",
"education",
"inspiration",
"a bed"
] | A | an animal requires energy to move |
OpenBookQA | OpenBookQA-4776 | 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.
Animals adapt to their what? | [
"appearance",
"feet",
"skin",
"nature places"
] | D | animals adapt to their environment |
OpenBookQA | OpenBookQA-4777 | botany, marine-biology, salt
Title: Mangroves and desalination of sea water I am not an expert but I guess that mangroves (or some other plants that thrive in sea water) perform some kind of desalination to extract fresh water from sea water.
Is this true? If yes, What biological mechanisms are used to remove salt from sea water?
I am interested in any research about biological desalination. This paper might be of interest to you: https://advances.sciencemag.org/content/6/8/eaax5253.
The researchers created a synthetic mangrove that actually performs desalination, using the principles of natural mangroves.
The introduction has a good overview of the main ways mangroves desalinate saline water, namely:
Physical blockage by suberin within cells walls
Selective permeability of cell membranes in root
Negative pressure caused by evaporation that acts as hydraulic pressure to cause take-up of water by roots
All these combine to turn the mangrove into a kind of natural RO (reverse osmosis) machine.
The following is multiple choice question (with options) to answer.
Desalinating water from the ocean does what to nearby fish? | [
"helps them out",
"makes habitat nicer",
"gives them money",
"demolishes habitat"
] | D | oceans cover 70% of the surface of the earth |
OpenBookQA | OpenBookQA-4778 | entomology, ethology, parasitology, ant, parasitism
Title: The emergence of Phengaris butterflies from ant nests The butterflies of the Phengaris genus (also known as Maculinea) are known to be brood parasitic. During the fourth instar, the caterpillars leave their food plant and mimic ant larvae, causing the ants to take them back to their nest as if they were ant larvae that had escaped.
While in the nest, the caterpillars mimic ant larvae by means both of surface chemicals and acoustic mimickry (including, I understand it, mimicking sounds made by queens!) After pupating, the pupa continues to engage in acoustic mimickry, although I can't find any reference to whether it does (or even could!) engage in continued chemical mimickry.
But I can't find anything in the literature regarding the adult butterfly's emergence from the pupa and exit from the ant nest. A non-academic book and some web pages claim that the alcon blue (Phengaris alcon) and mountain alcon blue (Phengaris rebeli) adults are no longer engaged in any form of mimickry at this point, and may be attacked by the ants. These accounts differ as to how likely an attack is, how much danger the butterfly is in, and the level of protection afforded by the butterfly scales.
The webpages I mention belong to a University of Copenhagen researcher (Dr. David Nash) who has published work in this field. This suggests that the claim is probably correct.
That said, none of the peer-reviewed publications coauthored by him appear to mention it, and each of the two webpages creates a different impression as to the level of danger involved:
"If an ant tries to bite the butterfly it will only get a mouthful of scales." states one, suggesting that there is little the ants can do to harm or hinder the butterfly. But the other states "The adult has to get out of the ant nest quickly to prevent the ants killing it."
The book is written by someone else. It cites three papers, which do discuss the larvae/pupae and ants. But none of these have any information regarding this specific topic.
The following is multiple choice question (with options) to answer.
A caterpillar is a part one of the mundane four stage life cycle of | [
"a machine",
"a company",
"an engine",
"a colorful invertebrate"
] | D | metamorphosis is when an animal changes from an immature form to an adult form |
OpenBookQA | OpenBookQA-4779 | newtonian-mechanics
I should add that the above is simply what I, as a physicist with a fairly long experience, suspect is what is going on. It is not something I have read about and I am sure there is somewhere a more thorough discussion. So I hope I am right; I think I have a good argument. As I have described it above, I have in mind mainly the last part of the process where the wood only moves a little relative to the metal. In the earlier part, when the wood moves through a larger distance, it is inertia that is the main consideration, just like in the party trick where you abruptly whisk away a table cloth and the dishes on the table stay where there are. The more abrupt the better.
Added remark
It occurred to me that there is another thing worth mentioning here, that makes this method preferable to resting the axe head on something, or supporting the handle on a work top and hitting the head. It is that by hitting the end of the handle, with the head just hanging, you are going to deliver the force more accurately at the join, because it travels along the handle in exactly the direction you want. If instead you strike the head then there is a danger it will be knocked slightly obliquely, introducing a random tilt with each blow, which is liable to deform the wood and thus loosen the fit.
The following is multiple choice question (with options) to answer.
A thing which has something firmly raked over it may | [
"lose a pebble",
"be built up",
"lose a portion",
"grow larger"
] | C | scraping an object may cause small particles to break off of that object |
OpenBookQA | OpenBookQA-4780 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
A mouse will most likely be hunted by an animal with | [
"a long neck",
"pointed teeth",
"dense fur",
"webbed feet"
] | B | carnivores are predators |
OpenBookQA | OpenBookQA-4781 | zoology, ecology, population-biology, ecosystem, predation
Title: Predator prey interaction I went through a line in my textbook which read:
"But for predators, prey species could achieve very high population densities and cause ecosystem instability."
I was not able to understand the meaning 'but for predators'. Can anyone please help me to interpret it's meaning?link to page where this line is mentioned
Edit: In terms of biology, I was unable to understand the meaning of the sentence, and I wanted to make sure that I don't misunderstand things... And this is why I posted the question.. I feel that the answer given is correct and in case, you find better explanation, please do post. I disagree with GForce's explanation; the meaning is not that growth of prey populations causes instability in predator species.
The sentence is merely saying that without predation, prey population growth is more likely to be at a level which leads to ecosystem instability. The term "but for predation" means "if it wasn't for the effects of predation". In other words:
"Ecosystem instability can occur when population growth of some species goes unchecked by predation."
See here for more explanation, where this example comes from in which it says that running a red light caused a crash:
"but for running the red light, the collision would not have occurred"
Biologically this makes sense in the sentence you show; without predators a species is limited by its supply of resources, and it can use these resources at an unsustainable level, whereas if you add predators to the mix there is additional extrinsic effects on population size, not determined by ecosystem properties such as space or nutrients.
The following is multiple choice question (with options) to answer.
What are predators? | [
"herbivores",
"plant eaters",
"meat devourers",
"peaceful"
] | C | carnivores are predators |
OpenBookQA | OpenBookQA-4782 | c, reinventing-the-wheel
/*
* e_emit_str: prints a string "str" according to "data->out.mode" and returns
* the length of the string, or "E_PRINT_ERROR" on error.
*
* Mode can be:
* * "E_OUTPUT_NONE": the string is not printed;
* * "E_OUTPUT_STREAM": the string is written on an open stream;
* * "E_OUTPUT_STR": the string is written on an array and then is
* added the null terminator "\0", make sure that the array is large
* enough!
*
*/
static int e_emit_str(struct e_print_data *data, char *str)
{
int length;
assert(data != NULL && str != NULL);
length = strlen(str);
if (data->out.mode == E_OUTPUT_NONE)
return length;
if (data->out.mode == E_OUTPUT_STREAM)
return fputs(str, data->out.file) == EOF ? E_PRINT_ERROR : length;
/* E_OUTPUT_STR */
strcat(data->out.str_ptr, str);
data->out.str_ptr += length;
return length;
}
/*
* e_emit_char: prints a character "chr" according to "data->out.mode" and
* returns 1, or "E_PRINT_ERROR" on error.
*
* Mode can be:
* * "E_OUTPUT_NONE": the string is not printed;
* * "E_OUTPUT_STREAM": the character is written to an open stream;
* * "E_OUTPUT_STR": the character is written to an array and then is
* written the null terminator "\0", make sure that the array is large
* enough!
*
*/
static int e_emit_char(struct e_print_data *data, char chr)
{
assert(data != NULL);
if (data->out.mode == E_OUTPUT_NONE)
return 1;
The following is multiple choice question (with options) to answer.
Charring is a result of | [
"open flames",
"the sun",
"the moon",
"ice"
] | A | fire causes burning |
OpenBookQA | OpenBookQA-4783 | telescope, optics
Title: Shouldn't this cause a fire? This website shows a telescope projecting the sun onto a blackboard: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun.21/
Why isn't the board catching fire? You can easily start a fire on a sunny day by targeting the focal point of a magnifying glass onto something flammable. Why isn't the telescope in this picture doing the same thing?
Photo by Luis Fernández García It could start a fire if the screen is at the focal point of the optical system. That is how you light fires with a magnifying glass.
Here, the blackboard is likely away from the focal point, so you can see the shape of the eclipse (and you get a bigger image) without setting things on fire.
Although this is fairly safe, there are a few things to pay attention to:
If you do this, make sure nobody can walk between the telescope and the screen, because if they go near the focal point, they could get very hot.
Doing this will cause your telescope to heat up. If there are any plastic parts, they can melt.
The telescope in the picture seems to have a small opening. Don't do this with a big telescope. You don't need to collect a lot of light.
Not an answer to the question, but an important note: Observing the Sun is the most hazardous thing you can do in astronomy. Make sure you know what you are doing before you try.
The following is multiple choice question (with options) to answer.
Which would a fire likely be the cause of? | [
"an ice formation in the ocean",
"a cat's unique fur pattern",
"a person eating a bowl of cereal",
"a scar on the back of a tiger"
] | D | fire causes burning |
OpenBookQA | OpenBookQA-4784 | adaptation
Title: How do longleaf pine trees adapt to the florida keys rainforest? I know that longleaf pine trees can be found in rainforests, but I can't find anything. This is sort of a too broad question but here are a few ideas. The second most fragile part of plants are the leaves. In the latitudes and elevations that experience freezing, plants have learned to abscise their leaves and go dormant for the winter season. Conifers have thick, waxy, very thin leaves that most conifers do not need to shed.
In a rainforest there is no danger of too cold temperatures. That is why there is an abundance of broadleaf trees and plants in the rainforest. Most of our indoor plants are tropical rainforest species.
There is also an awful lot of rain in a rainforest. There is a problem with leaves covered with water, as it inhibits the absorption of CO2. Beneath the leaf, O2 is released as a by-product of photosynthesis. Broad leafed plants that have adapted to an environment with lots of rain, little wind, and being crowded together have leaves designed to 'wick' the rain water off the leaf to run down the midrib and off the pointy tip or lobed or curled under leaf margins. This clears off the water and allows the plant to take up CO2, or it would not be able to do photosynthesis to make its own food for energy.
The other cool thing I can remember, is that broad leafs of plants are able to 'adjust' to the light. Similar to a 'solar sail' in outer space. If in full sun, those leaves get thick and stay smaller. If in shade, very normal in a rainforest, those leaves can thin and get larger in order to capture as much light as possible.
A better wording for your question would be, 'why is there an abundance of broad leaf species versus conifers in a rainforest'? If I've been able to translate your question correctly?
Hope this helps.
The following is multiple choice question (with options) to answer.
Pines will continue to grow making them | [
"toxic",
"endangered",
"reuseable",
"shorter"
] | C | wood is a renewable resource |
OpenBookQA | OpenBookQA-4785 | combustion, temperature, fuel
Of course a lot of other factors are involved but this crude picture gives at least some useful insight. This was discovered experimentally in the early days of engine design as the designers observed that different extracts from oil had different combustion properties in engines and refined the way oil was distilled to give them the behaviours they wanted in their engines.
The following is multiple choice question (with options) to answer.
The world is starting to use oil less and less because it is unable to | [
"be used in cars",
"be used one time",
"be used multiple times",
"be used in homes"
] | C | a renewable resource can be renewed |
OpenBookQA | OpenBookQA-4786 | newtonian-mechanics, classical-mechanics, material-science
Title: Mechanical Property Responsible for Folding I was wondering on which property does a material's tendency to fold depends upon.
When we push a metal plate, it seems to move forward. However a rug would start to fold and form crests. A piece of paper moves forward but folds very easily when an obstacle is present in its path.
This tendency to fold seems to be dependent on dimensions of object as well. A very large metal plate would fold in presence of a 'push' force.
This tendency also seems primarily dependent on friction and any other component of force towards the opposite direction( opposite to direction of movement).
Can this tendency be quantified? If such a topic of discussion already exists then please share the link or name of book. Yes. It's compressive failure. There are three main strengths considered in evaluating material strength; tensile (stretching), compressive (opposite of stretching), and shear (cutting).
What you are calling "folding" is usually called "buckling" or the sudden sideways deflection of a structure.
Think of your paper as a sideways column. Load is applied until it exceeds the compressive strength of the column, at which point the column buckles. Continued application of load will result in further deformations.
The following is multiple choice question (with options) to answer.
Which are all likely enabled by rock folding? | [
"oak trees, waterfalls, TVs",
"rivers, lightning bolts, fire",
"the Himalayas, spelunking, and valleys",
"cats, prairies, dogs, birds"
] | C | the Himalayas were formed by rock folding |
OpenBookQA | OpenBookQA-4787 | If the question is asking for the probability that either of the two cows is 2-coloured, we have
$$P(\text {1 cow is 2-coloured | both visible sides are black}) = \frac{P(\text {1 cow is 2-coloured and other is black}) \times P(\text {the black side of the 2-coloured cow is seen})}{P(\text{both visible sides are black})}=\frac{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}}{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}+\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}}=\frac{1}{2}$$
where $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when one is 2-coloured and the other is black and $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when both cows are black (these exhaust all possibilities for both visible sides being black).
The following is multiple choice question (with options) to answer.
A cow would prefer | [
"birds",
"metals",
"sushi",
"cucumbers"
] | D | cows only eat plants |
OpenBookQA | OpenBookQA-4788 | earthquakes, soil-science, bedrock
Title: Question regarding underground man-made facilities Why is it that underground facilities (or underground military bases) are almost always built into hollowed out mountains? Examples of (publicly known ones anyway) are Cheyenne Mountain Complex and Mount Weather government/ military facilities. Is having a highland/mountain a prerequisite for construction of military/government facilities? Is is not possible to construct facilities beneath lower ground, plains, dessert or under cities, besides subway stations and tunnels? Say if we wanted to build NORAD bunker somewhere deep beneath San Jose population centers, is this possible discounting the fault lines and permits for now? This question is not about earth science. If anything, it has more to do with engineering.
Strategic or critical defense or government infrastructure needs to be protected against explosive attacks, particularly nuclear attacks. A mountain offers a sizeable protective cap/roof to an underground installation. Similar levels of protection can be provided in flat ground, but the underground installation would need to be significantly deeper.
Critical parts of the installation would not be established within the mountain above the level of the ground surrounding the mountain; it would be established below.
Additionally, many mountains are composed on igneous rock: rock that solidified from a molten mass. Such rock, such as basalt or dolerite (diabase), is typically stronger than sedimentary rock and can thus offer better blast protection than sedimentary rock.
Also, if the installation is established igneous rock, the same strength parameters can also mean reduced geotechnical and subsequent ground support measures would be required for the underground voids that if they were established in sedimentary rock.
Cheyanne Mountain is composed of granite, and igneous rock that solidified while still underground. The NORAD installation within Cheyanne Mountain "was designed to ride out a nuclear attack". Having been completed in 1966, when tunnel boring machines were not a consideration, it was established using drill and blast methods and consumed 500 tons of explosives.
The following is multiple choice question (with options) to answer.
The Norwegian government maintains a special storage chamber 800 miles from the Arctic Circle for use in the event of a man-made or natural disaster. The storage structure is built in Arctic permafrost and holds | [
"seeds that are growing now",
"seeds for the Arctic animals",
"seeds that spread the permafrost",
"preserved seeds for reproducing edible crops"
] | D | arctic animals live in an arctic environment |
OpenBookQA | OpenBookQA-4789 | Kudos [?]: 4 [2] , given: 0
Re: Good set of PS 2 [#permalink] 19 Oct 2009, 08:02
2
KUDOS
Bunuel wrote:
4. A contractor estimated that his 10-man crew could complete the construction in 110 days if there was no rain. (Assume the crew does not work on any rainy day and rain is the only factor that can deter the crew from working). However, on the 61-st day, after 5 days of rain, he hired 6 more people and finished the project early. If the job was done in 100 days, how many days after day 60 had rain?
(A) 4
(B) 5
(C) 6
(D) 7
(E) 8
This one was solved incorrectly:
Days to finish the job for 10 people 110 days.
On the 61-st day, after 5 days of rain --> 5 days was rain, 55 days they worked, thus completed 1/2 of the job, 1/2 is left (55 days of work for 10 people).
Then 6 more people was hired --> speed of construction increased by 1.6, days needed to finish 55/1.6=34.375, BUT after they were hired job was done in 100-60=40 days --> so 5 days rained. They needed MORE than 34 days to finish the job, so if it rained for 6 days they wouldn't be able to finish the job in 100(40) days.
I solved in a more easier way I think:
1) 10 man 110 days --> need for 1100 man.days
2) 55 days with 10 men --> 550 man.days
3) 40 days with 16 men --> 640 man.days
--> total man.days equals 1190 vs need for 1100 --> days of rain equals 90/16 max --> 5.625 --> rounded to 5
Senior Manager
Joined: 31 Aug 2009
Posts: 420
Location: Sydney, Australia
Followers: 6
Kudos [?]: 165 [1] , given: 20
The following is multiple choice question (with options) to answer.
To replenish the shade in a city that had been provided by trees that were felled by a storm: | [
"grow gills and live on a raft",
"use a large lawn mower",
"get out your weed whacker",
"introduce replacement timber items"
] | D | timber companies cut down trees |
OpenBookQA | OpenBookQA-4790 | astronomy
Title: Can anything be seen from the center of the Boötes void? How dark would it be? Let's say I was at the very center of the enormous Boötes void, way out in deep, deep space. What could I see with the naked eye? I assume I could see no individual stars, but could I resolve any galaxies? If I gazed in the direction of a super-cluster of galaxies would it seem brighter than other directions? How dark would it be compared to, say, the far side of the moon when it is a full moon on earth?
I am told there are, in fact, a few galaxies in the void. So let's say I pick a spot in the void that is as far from any of those galaxies as possible. Individual sources
The number density of galaxies in a void is typically an order of magnitude lower than the average in the Universe (e.g. Patiri et al. 2006). In this astronomy.SE post, I estimate the number density of galaxies of magnitude $M=-17$ or brighter in the Boötes Void to be $n \sim 0.004\,\mathrm{Mpc}^{-3}$, or $10^{-4}\,\mathrm{Mlyr}^{-3}$ (i.e. "per cubic mega-light-year"). Hence, the typical distance to a galaxy from a random point in the Boötes Void is
$$
d = \left( \frac{3}{4\pi n} \right)^{1/3} \simeq 13\,\mathrm{Mlyr}.
$$
Although some galaxies will be brighter than $M=-17$, the number density declines fast with brightness; for instance, galaxies that are 10 times brighter are roughly 100 times rarer, meaning that they're on average 5 times more distant and hence appear 25 times fainter. On the other hand, the number density of galaxies fainter than $M=-17$ doesn't increase that fast (in astronomish: $-17$ is close to $M^*$; "M-star").
The following is multiple choice question (with options) to answer.
Which area would be brightest, if you woke up there? | [
"rainy environments",
"underwater environments",
"forest areas",
"frozen areas"
] | D | cold environments are usually white in color from being covered in snow |
OpenBookQA | OpenBookQA-4791 | zoology, digestive-system, pets
Title: Is it safe to feed an adult fire salamander with slime maggots? As a reminder, maggots feed of a flesh, while fire salamander consumes his prey alive, without killing it.
Can it happen that the maggot will start eating the salamander from the inside? Although I am afraid I don't know much about fire salamanders specifically, it is certainly possible for ingested fly larvae (or larvae hatching from ingested eggs) to survive ingestion and subsequently cause intestinal damage. Parasitic infestation by fly larvae that grow inside the host while feeding on its tissue is called myiasis. Enteric myiasis (also called gastric, rectal, or intestinal myiasis to indicate the affected part of the digestive system) occurs occasionally in humans following the ingestion of cheese infested with cheese fly maggots. Casu marzu, a traditionally produced Sardinian cheese, is supposed to have live cheese fly maggots in it, and cases of bloody diarrhoea following its consumption are known. If they're dead the cheese is considered unsafe to eat (although personally I'd correct that to 'more unsafe').
The following is multiple choice question (with options) to answer.
This creature eats cheese and is unable to lay eggs | [
"a fish",
"a bunny",
"a crab",
"a mouse"
] | D | a mouse gives birth to live young |
OpenBookQA | OpenBookQA-4792 | morphology, dinosaurs
Title: Based on morphology alone, what type of claw does the Tyrannosaur have? I understand that the exact use of Tyrannosaur Rex's claw is a mystery, or at least debated. I also understand that claws can be used for a variety of different purposes, selective pressure adapts their morphological to be better optimized for certain tasks. Some are used for hunting and killing, like large cats' claws, some are used for digging, like bear's claws, while others are used for climbing, like squirrel's claws.
My question is, all other clues and bits of information about if and how T. Rex might have used its arms, what 'type' of claws did it possess? I'm not asking, in this question, about its arm, the arm's musculature, its mouth or jaw, or about any of the rest of the animal. Based on the morphology of the claw alone, and comparing it to known uses of similarly shaped claws, what types of tasks were the claws geared towards? unfortunately they have fairly generic claws, they are not specialized enough to point to a use. They are curved enough to be used to grasp something but that is true for their ancestral line too so there is no sign of a specific directional selection.
The following is multiple choice question (with options) to answer.
a hawk will use their claws to touch which of the following? | [
"mouse entity",
"nuts and berries",
"lion",
"rhino"
] | A | a mouse gives birth to live young |
OpenBookQA | OpenBookQA-4793 | javascript, object-oriented, design-patterns, simulation
draw() {
const imageData = this.ctx.getImageData(0, 0, this.ctx.canvas.width, this.ctx.canvas.height);
const data = imageData.data;
for (let x = 0; x < this.width; x++) {
for (let y = 0; y < this.height; y++) {
let i = 4 * (y * this.width + x);
if (this.array[y][x] == null) {
// white water
data[i] = 255;
data[i + 1] = 255;
data[i + 2] = 255;
data[i + 3] = 255;
} else if (this.array[y][x].species === 'fish') {
// yellow fish
data[i] = 255;
data[i + 1] = 255;
data[i + 2] = 0;
data[i + 3] = 255;
} else if (this.array[y][x].species === 'shark') {
// red sharks
data[i] = 255;
data[i + 1] = 0;
data[i + 2] = 0;
data[i + 3] = 255;
}
}
}
this.ctx.putImageData(imageData, 0, 0);
document.getElementById('chrononText').innerHTML = this.chronon;
document.getElementById('fishText').innerHTML = this.numFish;
document.getElementById('sharksText').innerHTML = this.numSharks;
}
tick() {
this.chronon++;
for (let x = 0; x < this.width; x++) {
for (let y = 0; y < this.height; y++) {
if (this.array[y][x] == null) {
// do nothing
} else {
this.array[y][x].tick(this.chronon);
}
}
}
}
}
The following is multiple choice question (with options) to answer.
Swords are drawn to | [
"the devil",
"magnets",
"people",
"trees"
] | B | carbon steel is always magnetic |
OpenBookQA | OpenBookQA-4794 | meteorology, atmosphere, temperature
So, the temperature is falling over night after the sunset, but rises again after the sunrise. Thus, the temperature is at its lowest point in the morning.
Appendix for all you loving calculations:
Note: Simplified to toy model, no atmosphere
The cooling rate of the Earth is approximatelly given by the Stefan-Boltzmann equation:
$$j_E=\sigma\cdot T^4=5.670 \cdot 10^{-8} \frac{W}{m^2 K^4} \cdot (288.15 K)^4 = 390 \frac{W}{m^2}$$
The maximum heating rate of Sun in the zenith is $j_{\text{S max}}=1361 \frac{W}{m^2}$. So, the heating rate of Sun at altitude $\alpha$ is:
$$j_S=j_{\text{S max}}\cdot \sin{\alpha}=1361 \frac{W}{m^2}\cdot \sin{\alpha}$$
When is the heating rate equal to zero?
$$0=j_S-j_E=1361 \frac{W}{m^2}\cdot \sin{\alpha} - 390 \frac{W}{m^2}$$
$$1361 \frac{W}{m^2}\cdot \sin{\alpha} = 390 \frac{W}{m^2}$$
$$\alpha = 17 °$$
So, with our calculations, the minimum temperature is at the time when the altitude is equal to 17°.
The following is multiple choice question (with options) to answer.
The best time to have an all-day BBQ in the northern hemisphere is | [
"December 21st",
"the winter solstice",
"end of June",
"sometime in January"
] | C | the amount of daylight is greatest on the summer solstice |
OpenBookQA | OpenBookQA-4795 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
The main reason people want to use wind as an energy source is because there is | [
"make cookies",
"Sing songs",
"smile",
"an everlasting supply"
] | D | wind is an inexhaustible resource |
OpenBookQA | OpenBookQA-4796 | formal-grammars
Title: Useless production Kindly consider the following productions. How can I identify a useless production?
S->aS|A|C
A->a
B->aa
C->aCb
Somebody please guide me.
Zulfi. Starting from $S$ it is impossible to generate a sentential form that contains the nonterminal $B$.
This is easy to see since:
$S$ only has productions whose body contain $S$ itself, $A$ or $C$.
$A$ has no nonterminals in the body of its productions.
$C$ has only $C$ itself in the body of its productions.
This means that the production $B \to aa$ is useless.
The following is multiple choice question (with options) to answer.
The producer makes its own: | [
"body",
"sustenance",
"air",
"grass"
] | B | a producer is a source of sugar in an ecosystem |
OpenBookQA | OpenBookQA-4797 | Just to answer you, that is the third time someone told me that joke is supposed to be ten, yes, I know. But the joke it that it is not.
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The following is multiple choice question (with options) to answer.
It's wrong to | [
"pet a dog",
"cuddle a dog",
"love a dog",
"stomp a puppy"
] | D | harming something has a negative effect on that something |
OpenBookQA | OpenBookQA-4798 | theoretical-biology, hematology, red-blood-cell
**As an intern, I once had the very sorrowful experience of admitting an healthy appearing, exuberant 4 year old child to the pediatric surgical service. The only presenting symptom was that the child started squatting during exertion (not good), and on exam, had a murmur which was caused by aortic stenosis. This was long before imaging studies were as sophisticated as they are now. The pediatric cardiac surgeon took him to the operating room (OR) to replace the valve, but there was so much atherosclerotic aortic damage that there was no healthy tissue which could hold sutures in place. The child died in the OR. I don't know what would have been done today, but had the child stayed home, they might have had a couple more years with the parents, who hoped for an uneventful procedure. So the exercise involved in this answer was fun, but the memory it brought back is still quite sad.
The following is multiple choice question (with options) to answer.
Something that may effect a child negatively could be | [
"unicorns",
"magic",
"time travel",
"punching"
] | D | harming something has a negative effect on that something |
OpenBookQA | OpenBookQA-4799 | electromagnetism, experimental-physics, kinematics, magnetic-fields
Title: What is quartz, and how does it work in watch and electronic circuits? How does it helps in watch and electronic circuit broad?
Is there any material to refer? Quartz is silicon dioxide (SiO2); the crystal form called 'alpha-quartz'
is a hexagonal crystal (which you have probably seen, because it is a
common and rather attractive mineral). In that crystal form, the
application of stress will slightly polarize the material (cause electric
charge to move), and the inverse effect also holds (electric charge applied
to the crystal will cause it to change shape).
The final piece of the puzzle, is that quartz is acoustically 'live', i.e.
it rings like a bell. Like a bell, the acoustic pitch depends on shape
and size, so it can be shaped and sized for a
wide range of different frequencies of oscillation.
A sculpted piece of crystal can be used in an oscillating electric circuit to selectively
generate an accurate frequency. Tuning of radios was an early application, and many others followed. Networked data, like radio, requires accurate timing at multiple locations. Clocks, too, benefit from the mass-production of time standards in quartz crystal form.
The following is multiple choice question (with options) to answer.
Quartz are in | [
"affection",
"hollow spaces",
"love",
"spices"
] | B | a quartz is made of six-sided transparent crystals |
OpenBookQA | OpenBookQA-4800 | visualization
equating "relationship wealth" with "proportion of people of the opposite gender attracted"
the more a person is attractive the more they go for the top attractive people of the opposite gender,
Then for each gender the average number of likes received by level of attractiveness is calculated, for example:
In average a woman who has say 50% of attractiveness "likes" only 10% of the men, and we assume that she's going to like only the top 10% attractive men. Since this implies that the top 50% women are interested only in the top 10% men, it can be deduced by contrapositive that only the other 50% least attractive women can be interested by the 90% remaining (least attractive) men.
Another example from the other side: a man who has a level of 50% attractiveness likes all the women with more than 5% attractiveness in average. Again it is assumed that a woman who can attract a man in the top 50% will not be interested in the top bottom 50%, therefore the bottom 50% men can only "access" the bottom 5% of the women.
The whole graph is based on this assumption: if somebody at a particular level of attractiveness can attract the N% most attractive of the opposite gender, then anybody below this level of attractiveness is stuck with the remaining proportion. In other words it's not about how many people of the opposite gender one likes, it's about which level of attractiveness one can "afford" given their own level of attractiveness. That's what the graph shows: for example the 80% least attractive men can only afford the 22% least attractive women. By contrast the 78% most attractive women can afford to take their pick among the 20% top attractive men.
Beyond the caveats, my personal conclusion is: all you need is love... but can you afford it?
The following is multiple choice question (with options) to answer.
Self-absorbed people most love | [
"engaging in empathy",
"a lake's reflection",
"putting others first",
"thinking of others"
] | B | when light hits a reflective object , that light bounces off that object |
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