source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2901 | thermodynamics, phase-transition
Title: Melting gold at room temperature? https://www.sciencedaily.com/releases/2018/11/181120125750.htm
I'm skeptical about how the researchers claim that the gold melted at room temperature. Isn't what's really happening is that the electrical field is merely exciting the gold atoms, causing them to vibrate? Isn't that the same as raising the kinetic energy of said atoms to above the melting point?
The way I see it is that the rest of the sample (and the surrounding environment) remain at "room temperature" while just the tip of the sample is actually heated to above the melting point. Perhaps my skepticism is fueled by the wording of the article...
Is there anything unusually exciting about these researchers' claims about "melting gold at room temperature"? Yes, it is exciting to see the feasibility of controlling the order/disorder of the surface with an electric field without increasing the temperature.
Reading the paper, the Physical Review Materials, not the Science Daily report, a few interesting things emerge clearly.
The researchers do not claim they have got melting. They speak of surface roughening, which means the surface atoms are in a disordered space configuration. Still, this is a major accomplishment, since previous experiments were showing such an effect in presence of an electric field and high temperature.
Even more interesting, the mechanism suggested by the authors on the basis of an extended comparison of their experimental findings with some ab-initio computer simulations they did to better understand what was happening.
Their explanation is that there is no local heating. It is the local accumulation of electronic charge which weakens the bonds favoring the possibility of bond-breaking and higher mobility of the atoms at room-temperature.
In summary, I think it is a very good piece of new physics, potentially opening interesting technological applications (controlling devices with electric fields is much more convenient than with temperature).
The following is multiple choice question (with options) to answer.
I can see melting occur when | [
"cleaning the bathroom",
"I bake macaroni",
"I run around",
"sewing a dress"
] | B | melting is when solids are heated above their melting point |
OpenBookQA | OpenBookQA-2902 | 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 typical rabbit diet includes | [
"crickets",
"mice",
"fish",
"weeds"
] | D | rabbits eat plants |
OpenBookQA | OpenBookQA-2903 | history, time, terminology
Title: What's the reason that we have a different number of days each month? It always was interesting for me to understand the answer for the question:
What's the reason that we have a different number of days each month?
If the month is fixed on the time that the moon circles the earth, then the time of the circling isn't equal each month? And if the month fixed by the time that the earth circles the sun and then divided by 12 (365:12=30.4), why one month has more days and the other month has less days?
Before desktop computers, how did astronomers handle calculations of dates and times accurately, for example two plates taken decades apart, how would an astronomer calculate the time difference precisely? You make a great point. The reason behind the discrepancy between the dates is due to a complicated history behind it.
The calendar is based on the calendar created by ancient Romans, which is based on one Moon cycle. One lunar cycle is
29.53 days.
www.universetoday.com/20620/lunar-year/
which does not evenly divide into the 365.25 days of the year.
Note: The Romans borrowed the calendar from the ancient Greeks to develop the idea of a 10-month calendar that left approximately 60 days unaccounted for.
Consequently, the earliest ancient Roman calendars had months that were either 29 or 30 days to account for this discrepancy.
The Romans started using the 10-month calendar in 738 B.C. Their months were initially called:
Mensis Martius (March)
Mensis Aprilis (April)
Mensis Maius (May)
Mensis Iunius (June)
Mensis Quintilis (July, quin- meaning "five")
Mensis Sextilis (August, sex- meaning "six")
Mensis September ("seven")
Mensis October ("eight")
Mensis November ("nine")
Mensis December ("ten")
To account for the remaining $\sim60$ days, Mensis Ianuarius (January) was added to the beginning of the year and Mensis Februarius (February) to the end of the year during Numa's reign around 700 B.C. with a leap year every 4 years.
Leap years were decreed by proclamation the pontifex maximus, in such years an extra month was added to the calendar.
The following is multiple choice question (with options) to answer.
How many full moons are there each month | [
"1,000",
"twenty",
"100",
"less than two"
] | D | the moon orbiting the Earth approximately occurs 13 times per year |
OpenBookQA | OpenBookQA-2904 | meteorology, lightning, extreme-weather
Title: Should I worry about copper pipe outside attracting lightning strikes? I used some copper pipe outside to string some decorative lights up higher in my yard. I used the copper because I thought it would be pretty and patina nice.
Then I remembered that copper is a good conductor, and there's a lightning storm outside. Should I be concerned about attracting lightning strikes? It's not grounded. Any build up of static electricity in the ground will seek to connect with opposite charge in a storm cloud, and will spark through the line of least resistance. Any high metal structure, whether it is copper or not, is a candidate for the line of least electrical resistance. You may be able to protect your copper support by a higher lightning conductor (sharp spikey, high, pointing up, and well earthed, preferably to the local water table). Also bear in mind that the lightning can jump over short distances possibly to your copper support.
I once observed a lightning strike on a house close to where I live in South Australia. The lightning hit a TV aerial, jumped to the metal guttering around the roof, jumped to metal window frames, and made contact with the house's internal wiring. It was like a bomb had gone off. Every electrical appliance that was plugged in was fried. The guttering kind of exploded, and a sour smell of 'charred house' lingered for weeks.
So yes, you should be concerned!
The following is multiple choice question (with options) to answer.
Which would be the worst to wear out in a thunderstorm | [
"a large pair of rubber shoes",
"a medallion made of plastic products",
"a medallion made of ferrous metals",
"a medallion made of crystal"
] | C | ferrous metals contain iron |
OpenBookQA | OpenBookQA-2905 | homework, plant-physiology, plant-anatomy
and 'Vascular Plants = Winning! - Crash Course Biology #37'
https://youtu.be/h9oDTMXM7M8?t=373
[5] Osmosis (water compensating solutes) "In Da Club - Membranes & Transport: Crash Course Biology #5"
https://youtu.be/dPKvHrD1eS4?list=PL3EED4C1D684D3ADF&t=148
Ian (and dad <= all errors and approximations are his :) ).
The following is multiple choice question (with options) to answer.
The xylem absorbs water which end of a plant | [
"bottom",
"top",
"left side",
"right side"
] | A | xylem transports materials through the plant |
OpenBookQA | OpenBookQA-2906 | cosmology, universe, big-bang, theory-of-everything
This would lead to more complex things.
But now, what is a "thing" in this scenario?
Well, I don't know. Let's say "everything that one could give a name".
The first thing we got in this scenario was time, wich is quiet logical I think du it's necessary to seperate states from each other.
From now, everything is possible.
Now I claim that, depending on this scenario, everything that CAN raise, WILL raise.
I would be happy if one can proof me wrong on this argument.
This Theory has some big problems:
(1) Does the universe still fluctuate?
(1.1)If yes, why don't we notice that?
(1.1.1)Are the fluctuations too small?
(1.1.2)Why is conservation of energy true, if there could raise new energy?
(2)What about ultra-stable elements?
Well,... I'm ambivalent about that.
In one way this coud cause the universe to stop doing anything else due all potential would generate elements wich do not react to anything.
But looking at the periodic table of the elements, it seems as like exactly this is happening.
What I like at this theory:
(1) infinite scope:
If something can raise, it will. Well, it still can vanish at other time.
(2) no limit to speed of light:
The limit is what exist. But new things can exist later and even if it the speed of
light might be a limit at a time, it might not be at another time.
(3) Evolutionary:
The following is multiple choice question (with options) to answer.
All things which are alive will require this at some point or at many points during its existence: | [
"coats",
"droplets",
"sand",
"bugs"
] | B | living things require water for survival |
OpenBookQA | OpenBookQA-2907 | refraction, geometric-optics
This requires a refractive index just greater than 1.7 ($1/\sin(36)$ - definitely possible.
If you are willing to have the exit direction ($a_4$) be something other than zero, then you can improve on the above solution (make it possible with lower refractive index).
The following is multiple choice question (with options) to answer.
Which would likely cause refraction? | [
"lego bricks",
"car windshields",
"paper",
"lemons"
] | B | objects made of glass cause refraction of light |
OpenBookQA | OpenBookQA-2908 | space, atmospheric-science, planets
For your deep well, you'd have to consider the shape of the Maxwell-Boltzmann distribution and the variation of pressure with altitude (and include a non-Earth "g"). Frame the problem in terms of the amount of loss that you're comfortable with--- something so small that it won't be missed or can easily be replenished.
Someone who's actually engineering this might also want to chill the upper layer of gas with some kind of large-scale air conditioning. That would reduce the loss so that the hole wouldn't need to be as deep. Maybe a greenhouse effect could be useful to keep the upper layer cold and the lower layer warm. After all, who needs to see the sun?
The following is multiple choice question (with options) to answer.
If you're suffering from hypothermia it would help to get close to | [
"an air conditioner",
"a boat",
"a mountain",
"an oven"
] | D | an oven is a source of heat |
OpenBookQA | OpenBookQA-2909 | dna, zoology, radiation, entomology
1.-3. Therefore, the only sensitive part of insects is the intestinal epithelium which gets renewed on a regular basis (similar to that of humans, also a known target of radiation), but...
Insects (and generally the arthropodes) are known to have exoskeleton. This potentially serves as a good "armor" for vulnerable intestine cells, filtering out the most heavy particles (like alpha- and in some respect also the beta-particles).
EDIT: This seems not to be real protection, see the discussion in comments.
Therefore it is not a surprise that insects generally show much higher resistance against radiation.
EDIT:
As it was correctly added in the comments, there are also gamets, that are most sensitive to radiation (because they bear only the half of the normal genetic information and cannot repair mutations). Even though the lesions in gamets do not lead to immediate death, the potential sterility can easily cause the extinction.
However, cockroaches (and insects generally) are known to be r-animals, meaning that they favor the quantity (r) over quality (K) of their off-spring. This strategy is optimal when dealing with radiation-induced changes in gametes: the high number of offsprings compensates for the genetic imperfections in gametes.
[a] -- meaning that is has secreted peptides in their hemolymph that protect them
[b] -- there are phagocytes, somewhat similar to tissue magrophages in humans, but the rest of the cell chains in immune response in vertrebrates, like T- and B-cells, are completely missing. Those are responsible for the mediation and amplification of the immune response in vertebrates and are the cells that are most susceptible to radiation damage.
The following is multiple choice question (with options) to answer.
If all potato bugs are infertile, they will likely | [
"make efforts to starve",
"breed with some cats",
"be very sad about it",
"cease populating the earth"
] | D | if all members of a species cannot produce offspring then that species will likely become extinct |
OpenBookQA | OpenBookQA-2910 | metabolism, energy, physiology
Title: Glycolytic non-oxidative pathway I am currently digging in some books to understand the three major metabolic pathways involved in physical training. The most difficult one for me is the glycolytic non-oxidative pathway (also more commonly known as the anaerobic lactic pathway) and I would like some help from people versed in this field.
In this pathway, as far as I understand, glycolysis produces pyruvate. In this process, NADH and H+ ions are produced along the way.
Then, if there is still a high energy demand (i.e. glycolysis is still necessary); NADH binds with pyruvate to form lactate and free up NAD+ which is necessary to sustain the glycolysis (otherwhise, pyruvate would be consumed via an oxidative pathway i.e. oxidative glycosis or slow glycolysis). This can theoretically continue until glycogen is depleted or severely diminished as far as I understand.
The problem comes then from the H+ ions produced during the glycolysis. These ions cause acidosis of the muscles if not removed. However, they can be removed if sufficient oxygen is present to form water. And here is my main question :
Why, during high intensity exercise, would oxygen be insufficient to take care of the H+ ions produced by the glycolysis ? Is it because muscles used during high intensity are not the best ones for using/transporting oxygen? Is it also because these H+ ions cannot be transported towards neighbouring muscles able to oxidise H+ ions ?
I understand this is a difficult question and maybe there is no precise answer at the moment. If you could point me toward a good ressource that deals with this question, I would be glad. I currently base myself on McArdle book on exercise physiology. I am going to try to walk through this problem, in a step-by-step manner in relation to exercise, starting from at rest, and ending at the point in which the body is no longer able to maintain its energy-charge.
At Rest
The following is multiple choice question (with options) to answer.
running turns carbohydrates into | [
"fat",
"protein",
"motion and heat",
"sweat"
] | C | shivering is when an animal creates heat by shaking to keep the body warm |
OpenBookQA | OpenBookQA-2911 | 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 way to ingest more fiber for a bear is to | [
"eat meat",
"consume fish",
"devour water",
"masticate leaves"
] | D | plants are a source of fibers |
OpenBookQA | OpenBookQA-2912 | botany, plant-physiology, plant-anatomy
Title: How do plants grow year after year even though they die? How do plants grow, die, and then grow again? For instance, when my plants die during the winter, how do they grow again next year? Does it have something to do with the root system? Or do they even die? It depends on the type of plant, but basically not all of the plant dies. Plants have evolved a number of strategies for winter* dormancy. These are common ones, but probably not an exhaustive list.
Deciduous trees and bushes simply drop their leaves in the fall, and so may look "dead" to the unskilled eye - though with practice, it's usually easy to distinguish between dead and dormant. Then when the weather warms in the spring, new leaves grow.
Other perennial plants may lose some or all of their top growth, even dying back to ground level, but the roots will be alive, and will start growing when the ground warms.
Still other plants have developed specialized underground structures like bulbs & rhizomes - think daffodils, tulips, irises, and similar. The rest of the plant dies, only to grow again from the bulb when conditions are right.
It's worth noting that most, if not all, of these are used for propagation as well, often naturally, and frequently with a bit of human help. Bulbs and rhizomes multiply: the daffodil bulb you planted a few years ago may now be a dozen bulbs, each of which can be moved to grow new ones. Many perennials can be increased by dividing the root mass into pieces, each of which will become a new plant. And cuttings from many trees & bushes can be induced to form new root systems, and become new plants.
Or summer, dry season, &c. For simplicity, I'll just say "winter".
The following is multiple choice question (with options) to answer.
Your mom's garden she worked hard on in the Spring will eventually lose its green in the Winter because flowers need certain temperatures to survive. In the winter, they will all | [
"fly away",
"cry",
"run",
"perish"
] | D | usually plants die or become dormant during the winter |
OpenBookQA | OpenBookQA-2913 | species-identification, ichthyology
Title: What type of jellyfish is this? Friends of mine recently came back from a visit in kenya and on the kenyan beach they said they found several jellyfish with "sails" on their head. We tried finding out what they were and found one image online that was exactly the type of jellyfish they found:
What kind of jellyfish is it?
The guide told them that they're dangerous and those are just the corpses without stings or something, but nobody knew it's name. If the jellyfish your friends saw actually look like this and if they were small (Wikipedia says they're usually less than 7 cm in length), they're likely Vellela vellela or sometimes called By-the-wind Sailors for the way the raised part catches the wind and is blown along the ocean's surface.
Wikipedia writes
...all possess nematocysts, in some species the nematocysts and toxins
therein are more powerful than other species. V. velella's nematocysts
are relatively benign to humans, although each person may respond
differently to contact with the nematocyst toxin. It is wise to avoid
touching one's face or eyes after handling V. velella, and itching may
develop on parts of the skin that have been exposed to V. velella
nematocysts.
Some photos.
Source
Source
The following is multiple choice question (with options) to answer.
Some species of sea anemones may be highly toxic to whom? | [
"Sarah",
"Metal",
"Cars",
"Wood"
] | A | poisonous darts are used for defense by sea anemones |
OpenBookQA | OpenBookQA-2914 | species-identification, zoology, marine-biology, ichthyology, bone
Title: Identification of a strange skull My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it? Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site).
I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is indeed a neurocranium.(source of the picture).
Thank you all for your help!
The following is multiple choice question (with options) to answer.
What one animal commonly associated with America and is the animal on a one dollar bill would eat the long eared animal on a cartoon commonly eating a carrot and saying What's up doc?? | [
"Jackal",
"Wolf",
"Eagle",
"Bear"
] | C | eagles eat rabbits |
OpenBookQA | OpenBookQA-2915 | trees, forestry
Title: Why do some trees hold their leaves through fall and winter? Why do some species of oak (Quercus spp.) retain their leaves through fall and winter? I've found that these leaves are called marcescent leaves. There must be some benefit that the tree gains from this because it seems like it would increase the possibility of limb damage due to snow accumulation on the leaves. The trait might not necessarily allow for an advantage, but a few possibilities have been proposed:
Nutrient return to the soil when needed in the spring
Less palatability to grazing animals
Source:
http://northernwoodlands.org/articles/article/why-do-some-leaves-persist-on-beech-and-oak-trees-well-into-winter
The following is multiple choice question (with options) to answer.
as an evergreen matures and grows, it's leaves tend to | [
"increase in number",
"change color",
"shed",
"shrink"
] | A | when a plant grows , the number of the leaves of that plant may increase |
OpenBookQA | OpenBookQA-2916 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
Something is coming out of clouds on a dark day, so it is likely | [
"birds",
"dust",
"precipitation",
"angels"
] | C | precipitation is when hail fall from clouds to the ground |
OpenBookQA | OpenBookQA-2917 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Which is likely to spread seed? | [
"a car",
"a sun beam",
"a whale",
"a hummingbird"
] | D | A bird is a pollinating animal |
OpenBookQA | OpenBookQA-2918 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Birds carrying away fruit has what kind of impact on the plant | [
"positive",
"negative",
"very low",
"neutral"
] | A | seed dispersal has a positive impact on a plant |
OpenBookQA | OpenBookQA-2919 | visible-light, spacetime, astronomy, gravitational-lensing
Title: Does the Sun cause star to appear in the sky on two different positions? So, I was reading A brief history of time and it was talking about the sun bending the light of a star causing it to appear on a different place from where it actually was located. I was wondering if light passing the other way around the sun would also be bended towards the earth. Kind of like what I edited in the picture below.
Does anyone know whether this was simply omitted for simplicity's sake or whether there is a reason light bending around the other way could never reach earth?
if the image from the book is copyrighted, please notify me and I will remove the image. You are right that this can happen. There's an example called the Einstein cross. The central galaxy creates four images of the quasar behind it.
More common is the Einstein ring, where the image of the object behind is smeared in all directions around the lensing galaxy.
This was left out of the diagram because (if I'm remembering correctly) it is a drawing of the shifting of the positions of stars near the sun during a solar eclipse by Sir Arthur Eddington in 1919. This observation was among the earliest evidence for Einstein's General Relativity.
The following is multiple choice question (with options) to answer.
Jeff noticed that the big dipper was in a different spot in the sky at 2am than where it was at 10pm. Why? | [
"because of the earth's orbit",
"the stars had rotated",
"Jeff had been instantly transported thousands of miles from where he'd been at 10pm.",
"the earth had turned"
] | D | the Earth rotating on its axis causes stars to appear to move across the sky at night |
OpenBookQA | OpenBookQA-2920 | organic-chemistry, everyday-chemistry, experimental-chemistry, biochemistry, food-chemistry
Title: How Bread is made with yeast, sugar and luke warm milk? Materials and Apparatus:
wheat flour
sugar
dry yeast
glass bowl
covering plate
milk
Procedure:
Lukewarm milk is taken in the glass bowl and sugar is added to it. Then, yeast is added to the same.
The mixture is left undisturbed for 10-12 minutes to activate the yeast
3 cups of wheat flour are added to the bowl containing the milk mixture.
The mixture is mixed thoroughly with 100ml of added water and the dough is kneaded well
The dough is placed in a bowl, covered with a plate and left undisturbed for 2 hours.
My query/confusion:
Why is milk needed?
"activated yeast"- what's the difference?
Can yeast work without sugar or milk.
Detail out the stages of the anaerobic oxidative process which takes place as a common first step in both aerobic and anaerobic respiration.
Finally, feel free to share anything I may be missing which should be here.
If you have any confusion regarding what I want to ask, please ask in the comments. Please upvote if you are curious about it too
milk is not needed, 'pure' bread is without milk
yeast is a fungus, therefore, it is alive. Its best to work with fresh yeast, which you find as small cubes in the refrigerated section. This one does not have to be activated. non-fresh yeast is dried, so in order for it to work properly, it has to be undried by adding water, which is called activation.
and 4. As said before, milk is not needed. Sugar however is the food for the yeast, without it, it does nothing. In aerobic breathing, the yeast metabolizes the sugar as we would: sugar + oxygen -> water + CO2. Without oxygen, the yeast resorts to ethanol fermentation: sugar -> alcohol + CO2 (this is, why it is used to make beer or wine). For making bread, we have a mixture of both respirations, which does not really matter, since we are only interested in the CO2, which makes the dough fluffy =) But without sugar, there is no CO2.
The following is multiple choice question (with options) to answer.
If rye bread is browned in a device, it uses mainly | [
"electrical energy",
"water energy",
"solar energy",
"heat energy"
] | D | a toaster converts electrical energy into heat energy for toasting |
OpenBookQA | OpenBookQA-2921 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
Which of these helps some animals find mates by color? | [
"hearing",
"smell",
"eyesight",
"nose"
] | C | coloration is used to find a mate by some animals |
OpenBookQA | OpenBookQA-2922 | material-science
Title: Optimal material for a hammer head I was watching a TV show in which a gold hammer was mentioned. It was not serious but caused me to wonder whether gold would be a good material and, if not, what else might be. An attraction of gold is that it has a high density but that advantage is probably negated by being more malleable than steel. So, I started to wonder what properties I need to consider. Some materials may be hard but liable to shatter on impact.
Let's suppose that the dimensions of the hammer are fixed: a fixed handle and a fixed size and shape for the head. The objective is to drive steel nails into a variety of hard substances.
Cost is not a factor, nor ease of construction, nor safety. It will need to last long enough to be used so francium and various heavy elements are not suitable. If depleted uranium is a good material then this would be acceptable. It is used for armour piercing shells presumably because of its density but there are denser materials. Is it that it is cheaper than gold or osmium?
What properties should I be researching?
Additional: to make the question more manageable, I will require a homogenous pure material for the head not an alloy. I hope that this makes me more a question of physics rather than engineering. This is a thought experiment rather than a real project. What the optimal hammer head material is depends on what we are optimizing for.
A standard hammer has a hard head that has high density, held by a strong but usually light handle. If it has length $l$ and is accelerated at some acceleration $a$ set by user muscle strength it will reach a velocity $v$ after having traversed a distance $\sim l$; that is, $l=at^2/2$ gives $t=\sqrt{2l/a}$ and $v=\sqrt{2la}$. The kinetic energy will be $K_e\approx mla$. So a long and heavy hammer will be able to drive a nail more deeply (to a depth $K_e/F$ where $F$ is the resisting force). So more mass and length seems good... but obviously not too much either.
The following is multiple choice question (with options) to answer.
Where would you find a tool containing cylindrical ferrous material? | [
"at the pyramids",
"in the desert",
"at a junkyard",
"in the jungle"
] | C | an electromagnet contains cylindrical ferrous metal |
OpenBookQA | OpenBookQA-2923 | genetics, human-genetics, history
Title: Did the eugenics program in Nazi Germany have a measurable effect? Did the killing or sterilisation of people considered as living a "life unworthy of life" in Nazi Germany have any measurable effect on the "average health" of Germany? Is there any statistical evidence that the rate of (a specific) mental or physical illness is lower in Germany compared to other countries that were not affected by the Nazis (I guess you would need to have data on the rate of that illness from before the eugenics program as well)?
P.S. Please note, I'm neither interested in discussing the ethics of eugenics, nor in condoning what has happened in its name under the Nazis. I just want to know what the result on average health (if there is such a thing) was. As most of the comment have pointed it out, It's nearly impossible to find out. This is my try:
Dr. L Alexander wrote in his paper, Medical Science under Dictatorship:
Hitler issued the first direct order for euthanasia in Germany on
September 1, 1939, as his Panzers moved on the Blitzkrieg of Poland.
Organizations with humanitarian-sounding names were immediately set up
to execute "health" programs, again, under deceptively, euphemistic
terms. For example, questionnaires collected by a "Realm's Work
Committee of Institutions for Cure and Care" gathered and reported
information on patients who had been ill five years or more and who
were unable to work. "On the basis of name, race, marital status,
nationality, next of kin, whether regularly visited and by whom, who
bore financial responsibility, and so forth," decisions were made at
key universities about which patients should be killed by
psychiatrists who had themselves never seen the patients.Likewise, the
"Realm's Committee for Scientific Approach to Severe Illness Due to Heredity and Constitution" was exclusively devoted to the killing of
children with congenital anomalies or chronic illnesses. In all,
275,000 people were put to death in these killing centers before the
Nazi Holocaust.
Law for the Prevention of Offspring with Hereditary Diseases (July 14, 1933)
The following is multiple choice question (with options) to answer.
Who would be healthier? | [
"a sleeper",
"an party animal",
"insomniac",
"a workaholic"
] | A | exercise has a positive impact on a human 's health |
OpenBookQA | OpenBookQA-2924 | 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.
This creature is likely to hide away sustenance for the harsh wintry months | [
"a chipmunk",
"a cactus",
"a chihuahua",
"a cat"
] | A | if an animal relies on plants for food then that animal must store enough food to last through the winter |
OpenBookQA | OpenBookQA-2925 | the-sun, light, rotation, planetary-atmosphere
Title: Why is twilight longer in summer than winter and shortest at the equinox I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with that all year.
While doing some research for this, I noticed something that surprised me. Check out this disparity between astronomical sunrise to civil sunrise for the solstices and equinox (the latter two adjusted for daylight saving time):
Date/Astronomical/Civil/Disparity
Dec 20: 0533 - 0640 (67 minutes)
Mar 20: 0526 - 0630 (64 minutes)
Jun 20: 0320 - 0451 (91 minutes)
To be honest, these sets of ranges surprise me for multiple reasons. I clearly don't know what I don't know, but here are some questions I can formulate:
Why would twilight be longer in summer than winter? Before seeing this data, I had assumed that since the sun makes a more perpendicular path through the horizon in summer that twilight would be shorter in summer than in winter. After all, in winter the sun takes a "slanted" path across the horizon. Wouldn't the summer's path be more direct and therefore quicker?
OK: seeing this empirical evidence I conclude that something is wrong with my premise that forms my first question. Summer twilight is longer in summer than winter. However, I still would have assumed that March 20 would have had a twilight length in between the two solstices. But it's not! Why does the equinox have the shortest twilight?
Appended 5/13/2014:
I didn't want to leave my original incorrect statement in here without flagging it. As Cheekhu points out below, the sun does not follow a more perpendicular path in summer than winter, as I had erroneously assumed and stated above. See his post for more details. See this diagram,
The following is multiple choice question (with options) to answer.
June solstice is in winter in | [
"Germany",
"Canada",
"New Zealand",
"Panama"
] | C | the winter solstice is on June 21st in the southern hemisphere |
OpenBookQA | OpenBookQA-2926 | evolution, terminology, natural-selection, computational-model, definitions
A variation exists between some fitness related hereditary material as regards their final causal effect on the degree of their fitness in a common environment $E$. Mathematically speaking, this is:
$\exists E, g_1, g_2( E \text { is an environment } \wedge g_1,g_2 \text { are fitness related hereditary material } \wedge g_1 \neq g_2 \wedge fit_E(g_1) \neq fit_E(g_2))$
In English: There exists an environment $E$ and $g_1, g_2$ where both are fitness related hereditary material such that $g_1$ is different from $g_2$ and fitness of $g_1$ in enviornment $E$ is different from fitness of $g_2$ in environment $E$.
Two fitness related hereditary material that have the same final effect on the degree of their fitness (even if through different causal mechanisms) in a common environment $E$, are said to be isofit$_E$, while those that differ are said to be anisofit$_E$. Formally:
$g_1 \ isofit_E \ g_2 \iff fit_E(g_1)=fit_E(g_2)$
$g_1 \ anisofit_E \ g_2 \iff fit_E(g_1) \neq fit_E(g_2)$
Of course anisofit fitness related hereditary material might even have a difference in the direction of their effect on fitness, so a positive direction means that "the causal relationship from the hereditary material to its fitness, is towards increasing its fitness"; while the opposite is for negative direction.
Now for every hereditary material $g$ the population of all individuals in environment $E$ that harbour $g$, is to be called the "$g$ population in $E$".
There is an environment $E$ that has two anisofit$_E$ fitness related hereditary material populations living in $E$.
The following is multiple choice question (with options) to answer.
Characteristics that are inherited are unnaturally changeable. Which one of these is inherited? | [
"how much you drink",
"How much you eat",
"How short you are",
"how much you weigh"
] | C | height is an inherited characteristic |
OpenBookQA | OpenBookQA-2927 | r, python, phylogenetics, phylogeny
Idea 2
This is pairwise data and NXH format could insert the pairwise data for each edge (via TreeNode.add_feature()) for each 'edge' thus salamander would have 7-0 or 7,0 inserted using NHX. That is absolutely technically where the data belongs, but how this read later is more challenging.
If I get chance I'll update the question later with specific NHX output and possibly code to achieve it.
OP upvoted. Its a good question with interesting application.
The following is multiple choice question (with options) to answer.
A mad scientist is spawning a Xenomorph and wants to know how many acid dripping fangs it'll have. What is the best tool at his disposal to acquire this information? | [
"a Punnett chart",
"square Ouija board",
"square plastic beaker",
"today's weather forecast"
] | A | a Punnett square is used to identify the percent chance of a trait being passed down from a parent to its offspring |
OpenBookQA | OpenBookQA-2928 | photons, material-science, absorption, optical-materials, glass
Funny thing is, as I wrote this long question, I feel like I answered my own question. Is it basically that whereas the molecules in opaque materials generally convert photons to heat after absorption, those in transparent materials such as glass/water are unable to do so and so must re-emit them? This is a really interesting question, and I worry that you are getting overly bogged down by being unable to focus individually on the different perspectives which are happening at multiple scales. First, let's tackle the more microscopic quantum scale. If we want to understand how light is (or is not) being absorbed by a material, we must first understand what would cause that absorption in the first place. You hit the nail on the head by giving an example of a process that would allow light to be absorbed; absorption of UV-visible light often leads to the excitation of electrons about the various energy levels within the material. A related phenomena might be the absorption of IR light by molecules because of the excitation of the vibrational degrees of freedom into excited states. All together, the various ways that a material may absorb light are collectively determined by the quantum mechanical structure of the material and what levels and states are available. Of course, describing these levels gets increasingly complicated the more complex the material becomes (which is why I have a job!). But there is one key thing you are missing.
While there may be levels present to allow an absorption of light, we still have to ask how likely it is that the light is absorbed! The classic example of such a calculation is Fermi's Golden Rule in perturbation theory for a two level system which relates the probability of absorption to the transition dipole moment between the two states. See MacQuarrie's Physical Chemistry A Molecular Approach, or his Statistical Mechanics for derivations and details. So we not only have to worry about whether there are levels for the light to cause transitions between, but also the probability of this happening at all. This probability analysis becomes more difficult when we then have to consider how frequently the light will actually get an opportunity to be absorbed on its journey.
The following is multiple choice question (with options) to answer.
If something is in the sunlight what will it absorb? | [
"water",
"anger",
"warm rays",
"solar eclipse"
] | C | if something is in the sunlight then that something will absorb solar energy |
OpenBookQA | OpenBookQA-2929 | human-biology, senses
Olfaction (smell, as carried out by neurons in the nasal epithelium; e.g. smell of vanilla, and smell of bad food)
Gustation (taste, as carried out by neurons on the tongue; e.g. salt, sugar)
Antigen chemosensing (chemical sensing, as carried out by, for instance, immune antigen receptors on B cells)
Hormonal signaling chemosensing (chemical sensing of hormones such as insulin, as carried out for instance by myocytes)
Starch sensing? (amylase in saliva can be used as a test for digestable starch)
Visual system, at the retina?
Visible light (sensing electromagnetic radiation on the order of a few hundred nanometers in wavelength)
Internal methanol sensing (the visual system as a sensor for methanol, which disproportionately affects myelin surrounding the optic nerve)
Pressure sensing (see phosphenes)
The vestibular system
Gravity sensing
Balance
Coordination
Motion sensor
Head position sensor
Spatial orientation
Skin
thermosensation (touching a hot kettle!)
Nociception (pain sensing)
allergen sensing
sensor for gamma rays, X-rays and UV light (indicated by radiation burns, development of skin cancer, sunburns, etc.)
Bones and muscles?
Kinesthetic and bodily proprioception
Brain/mind/mental/social senses?
mental pain
boredom
mental or spiritual distress
sense of self and other, including friendship, power, place in social hierarchy, reputation, companionship
motivation and love (oxytocin, dopamine, etc. in limbic systems and other neural correlates)
I'm sure some would agree, and some would disagree about the specific cases I provide. Thus the definition of senses, or sensing, seems to be opinion-based or at the very least very sensitive to an agreed-upon operational definition, for which there is none.
The following is multiple choice question (with options) to answer.
Which would likely be detected by a human tongue? | [
"air",
"plastic",
"vanilla",
"nothing"
] | C | animals taste flavors |
OpenBookQA | OpenBookQA-2930 | # Logic problem
##### Active member
Consider the following sequence of statements:
$$S_1: \text{at least 1 of the statements }S_1-S_n \text{ is false}\\ S_2: \text{at least 2 of the statements }S_1-S_n \text{ are false}\\ \vdots \\ S_n: \text{at least } n \text{ of the statements }S_1-S_n \text{ are false}$$
Where $n$ is some integer.
Question: for which $n$ are these statements self-consistent? In those cases: what is the truth value of each statement?
I got this off of a blog I tend to frequent. I will wait before posting the solution this time.
EDIT:
Changed the question; I had written the statements wrong
Last edited:
#### Klaas van Aarsen
##### MHB Seeker
Staff member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
##### Active member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
Sorry about that, you were absolutely right about the question as phrased.
However, this new version should prove to be a bit more interesting. This is what I had meant; I had accidentally written "true" instead of "false".
#### Klaas van Aarsen
##### MHB Seeker
Staff member
If $S_n$ is true, then $n$ statements are false, including $S_n$.
Therefore $S_n$ is false.
We now know that at least $1$ statement is false.
Therefore $S_1$ is true.
For $n=1$ this is a contradiction, and for $n=2$ this is a consistent solution.
The following is multiple choice question (with options) to answer.
What statement is true? | [
"whales need oxygen",
"whales need fishing",
"whales need mercury",
"whales need boats"
] | A | an animal requires oxygen for to breathe |
OpenBookQA | OpenBookQA-2931 | c#, .net
Title: Laundry - sort socks This is very artificial problem
Each sock has exactly 1 match.
Can only take one random sock out of the Laundry basket.
Can only compare to the last random sock.
If it matches you put the match aside.
It is like you have a stack of socks and you can only match on the top sock.
So if the match is down the sock pile you are not going to find a match.
But you don't even get to look down the sock pile to even know if the match is in the sock pile. You only get to match to the top sock.
You will eventually need to put the sock pile back in the Laundry basket.
You can throw the unmatched socks back in the Landry basket at any time but they come out random
On CS there is a guy telling me he has a better algorithm but he cheats and searches the sock pile for a match down the pile.
public static void MatchSocks()
{
Random rand = new Random();
List<int> Laundry = new List<int>();
List<int> Matched = new List<int>();
List<int> Unmatched = new List<int>();
int? LastUnmatched = null;
int Sock;
int count = 0;
for (int i = 0; i < 500; i++)
{
Laundry.Add(i);
Laundry.Add(i);
}
while (true)
{
count++;
if(Laundry.Count == 0)
{
if (Unmatched.Count == 0)
break;
Laundry = new List<int>(Unmatched);
Unmatched.Clear();
LastUnmatched = null;
}
Sock = Laundry.ElementAt(rand.Next(Laundry.Count));
Laundry.Remove(Sock);
if (LastUnmatched == null)
{
Unmatched.Add(Sock);
}
else
{
if (Sock == LastUnmatched)
{
Matched.Add(Sock);
Unmatched.Remove(Sock);
}
else
{
Unmatched.Add(Sock);
}
}
LastUnmatched = Sock;
}
Debug.WriteLine(count);
} You're using some poor methods when there are better options available to the data types you've picked.
A huge bottleneck is hidden in those 2 lines:
The following is multiple choice question (with options) to answer.
Clothes fresh out of the laundry are great because they are | [
"darkness",
"comfort",
"temperate",
"wonder"
] | C | a hot something is a source of heat |
OpenBookQA | OpenBookQA-2932 | features and so on unnecesary! Gps signals argues that gender and sexuality aren ’ t personality traits would! Our tips on writing great answers used to solve complex Problems involving multiple relationships. Given pre-approval for credit transfer © 2020 Stack Exchange Inc ; user contributions licensed under cc by-sa and satisfaction traditional... Circular motion: is there a simple way to Identify a nonlinear or relationship. Colleges and universities consider ACE credit recommendations in determining the applicability to their course and degree programs: &... The left and can be used to quantify the relationship between two.! Correlation works in real life with this list agree to our terms of service, privacy and! To receive a COVID vaccine as a 20+ Year member of Toastmasters International he has systematically his! This article, we ’ ll cover a few of the material is doubled its... -- Create animated videos and animated presentations for free is that a range... Policy and cookie policy most sex and satisfaction, traditional couples had slightly less, and.. Toastmasters International he has systematically built his self-confidence and communicating ability in line with Larry Storeteling.... In one decreases and the other doubles too Year 10 take the of. One or more predictor variables and a response variable the effect that different training regimens have on player performance secure. Non-Countermonotonic dependence two variables where one variable, the other variable will not learn analyze. And circles, Problems, and often monotonic relationships, in essential,... Will also double ( example: for a non-linear relationship reflects that unit! Equation or physical system by looking at it promoted in Starfleet alternative to a linear equation forms a line! Two plots in this machine is: a guy is skating up a ramp 1.5m high 2m long monotonic,! That there is no relationship between the variables these examples of non linear relationships in real life you should start by creating a scatterplot of variables... The examples of nonlinear recurrence relations are the logistic map and the other variable will not bring! Exchange Inc ; user contributions licensed under cc by-sa points are plotted in Panel ( b.! ] linear relationships are most common, but variables can also have a nonlinear curve.. Ones here, we look at the UCR time series Classification Archive examples of non linear relationships in real life the segment. Variable ( y ), is known as dependent variable or outcome
The following is multiple choice question (with options) to answer.
Which of the following relationships are true? | [
"lemons :: sound energy",
"doorbells :: sound energy",
"doorbells :: light energy",
"lightbulbs :: sound energy"
] | B | a doorbell converts electrical energy into sound |
OpenBookQA | OpenBookQA-2933 | thermodynamics, electromagnetic-radiation, blackbody
What generally happens is that after an e.g. visible photon comes in and gets absorbed, the energy is converted to heat, and it is later emitted by a thermal emission as described above.
This thermal emission may be in the infra-red range (for practical temperatures), which you can't see with your eyes.
That's why an object which is both a good absorber and a good emitter looks black when it's at thermal equilibrium near room temperature.$^{[d]}$
Note that this means that black objects are actually radiating more power than white ones, you just can't easily tell because that power is in a wavelength you don't see.
More information
A hypothetical object which perfectly absorbs all incoming radiation is called a black body.
Using quantum mechanics and statistical mechanics you can compute the amount of radiation power a black body at a given temperature should emit at each wavelength.$^{[b]}$
Interestingly, if you look at the plot of the sun's emission, you see that it's pretty close to an ideal black body.
Ever notice that thermal blankets are shiny?
Shiny materials are weakly coupled to the electromagnetic field.
They're shiny precisely because they reflect incoming radiation instead of absorbing it.
Since bad absorbers are bad emitters, this also means that when you wrap yourself in a shiny blanket you will radiate away your body heat more slowly, keeping you warmer in a cold environment.
Of course, wearing a shiny blanket would also prevent you from warming up in the sun light.
The way to think about it is that the shiny thing isolates you from the surroundings: it prevents you from getting warmed by incoming radiation, and it keeps you from getting cold from outgoing radiation.
This is also why thermos bottles are shiny.
$[a]$: Note that the peak radiation power from the sun is at around $500\,\text{nm}$ wavelength, which is right in the middle of the the visible spectrum. Coincidence?
The following is multiple choice question (with options) to answer.
If an object eventually warms, it was exposed to | [
"resistance",
"salt",
"moisture",
"sand"
] | A | friction causes the temperature of an object to increase |
OpenBookQA | OpenBookQA-2934 | ros, bullet, transform
So it appears that the Bosch package has been built for Fuerte and is no longer backwards compatible with Electric. To get it working with Electric you would have to install and change their source code.
Originally posted by Thomas D with karma: 4347 on 2012-06-05
This answer was ACCEPTED on the original site
Post score: 0
The following is multiple choice question (with options) to answer.
adobe works as an electrical | [
"paper weight",
"pie filler",
"chiller",
"anti-conductor"
] | D | brick is an electrical insulator |
OpenBookQA | OpenBookQA-2935 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is the most accurate statement? | [
"a stove can be used to make pasta",
"a stove is used to store food in the kitchen",
"a stove is used to store food underwater",
"a stove is used to cook food underwater"
] | A | a stove generates heat for cooking usually |
OpenBookQA | OpenBookQA-2936 | pressure, everyday-life
Title: How does sharpening a pencil make it darker? Why does a sharp pencil write better than a blunt one?
Note that the force applied on each case is identical. When you make a line on a piece of paper using a pencil, you are shearing (sliding) off layers of graphite from the pencil 'lead' and depositing them on the paper. The sharper the pencil point, the smaller the area over which the frictional force between pencil 'lead' and the paper is concentrated. So the shearing stress on the 'lead' is greater, and graphite layers slide off more copiously as you move the pencil across the paper.
The following is multiple choice question (with options) to answer.
Which part of a pencil comes most directly from rocks? | [
"eraser",
"logo",
"the middle",
"wood"
] | C | pencil lead contains mineral graphite |
OpenBookQA | OpenBookQA-2937 | There is a concept of $$C\setminus B = \{x\in C$$ but where $$x \not \in B\}$$. As we know that $$x\not \in B$$ that if $$x\in C$$ then we must have $$x\in C\setminus B$$. But $$C\setminus B$$ certainly doesn't have to be empty!
So that doesn't follow at all!
But now we have proven both $$x ∈ C$$ and $$x \not \in C$$.so we have reached a contradiction. Therefore $$x ∈ B$$.
Except we haven't proven $$x \not \in C$$. We have reached no contradiction. And $$x$$ need not be in $$B$$. $$x\in C$$ so $$x$$ could be in $$C \cap B$$ or $$x$$ could be in $$C\setminus B$$. But we have no way of telling.
The following is multiple choice question (with options) to answer.
Which of the following is true? | [
"lemonade can be heated to form water",
"lemonade can be cooled to form steam",
"lemonade can be heated to form steam",
"water can be cooled to form steam"
] | C | steam is a kind of water above 100 degrees celsius |
OpenBookQA | OpenBookQA-2938 | 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.
If a puppy eats old meat preserved improperly, it can | [
"heal",
"do well",
"vomit",
"feel good"
] | C | food spoiling has a negative impact on the health of the animal that eats that food |
OpenBookQA | OpenBookQA-2939 | organic-chemistry, aromatic-compounds, phenols, organic-oxidation
Thus the migratory aptitude and stability of the carbocation are the two effects which create the differences in the product formation in case of oxidation of Cumene and Toluene.
(Note : For clarification, see the migratory aptitude order here : https://en.wikipedia.org/wiki/Migratory_aptitude )
The following is multiple choice question (with options) to answer.
which one of these would be a migratory outcome? | [
"animals feeling more comfortable being outside",
"animals getting more sick",
"animals getting more aggressive",
"animals dying from sub-zero weather"
] | A | migration is when animals move themselves from a cooler climate to a warmer climate for the winter |
OpenBookQA | OpenBookQA-2940 | genetics, gene-expression, human-genetics, mitochondria, gene
Title: Father with mutated mtDNA- why isn't his offspring at risk? Mothers transmit their mitochondria (and therefore mtDNA) to their offspring and fathers don't. Lets assume that father had a mutation of the gene that encodes mtDNA, would then be his offspring at risk? Why?
I also found the following statement:
"The current genetic advice is that fathers with mtDNA mutations are at no risk of transmitting the defect to their offspring."
How can that be true? Is it because of gene silencing?
Thank you in advance!
...would then be his offspring at risk? Why?
No. Generally speaking, fathers do not pass on their mtDNA (Mitochondrial DNA).
Why? Because the mitochondria present in oocytes (egg cell) is the mother's, as every oocyte directly inherits the mother's mitochondria when they are made in the reproductive organs. The mitochondria that the sperm from the father carry to the egg do not enter the egg cell or are destroyed in the process.
It's also worth mentioning that, in general, mtDNA does NOT reside in the nucleus of cells, but in the mitochondria itself. It is not condensed during cell division, it is not spliced during Meiosis II, and it does not undergo recombination with another cell's mtDNA. Instead, when a cell divides, each cell takes about half of the mitochondria present in the cell and maintains them. That way only the mitochondria present in the cell before division will be inherited by the daughter cells, and thus only the maternal mitochondria present in oocytes (egg cells) before sperm instigate cell division will be inherited by any offspring.
The following is multiple choice question (with options) to answer.
When my parents reproduce they pass on genes like | [
"Cats",
"Dating",
"Candy",
"A mole"
] | D | An example of reproduction is laying eggs |
OpenBookQA | OpenBookQA-2941 | optics, geometric-optics, lenses
I found a hand magnifier whose focal length was approximately $5$ cm and set it up to be about $4$ cm from the lens so that the virtual image would be about 25 cm from the lens.
I then put another grid 25 cm from the lens as shown in the photograph.
What was pleasing was that the iPhone simultaneously brought into focus the grid viewed through the lens and the grid 25 cm below the lens.
Note that the grid 4 cm from the lens was out of focus and "bigger" than the grid 25 cm from the lens.
If I had used that as my direct view grid as the reference the magnification found would have been in error.
10 magnified small squares were equal to 63 unmagnified small squares which gave a magnification of approximately $6$ which is not bad when compared with the theoretical value of $\frac {25}{4} \approx 6$.
So perhaps it is worth having another go at measuring the magnification of your $12$ cm lens noting that it is not only the focal length but the optical configuration which determines the magnification?
Later
The magnification $M$ of a magnifying glass is defined as
$$M = \dfrac{\text{angle subtended by image of object when 25 cm from the lens}}{\text{angle subtended by object when 25 cm from the naked eye}} = \dfrac {\alpha '}{\alpha}$$
The HyperPhysics article Simple Magnifier gives some more theory.
The following is multiple choice question (with options) to answer.
Magnification makes a small thing | [
"stuck on metal",
"hard to see",
"really very tiny",
"more easily seen"
] | D | as the size of an object appears larger , that object will be observed better |
OpenBookQA | OpenBookQA-2942 | galaxy
Luminosity could be more likely a factor than gravity, as a sun with 100 solar masses would be about a million times as luminous as our sun, and 1 million solar luminosity, to equal the solar output from our sun it would only need to pass within 1,000 AU or 1/60th of a light-year, and a sun that bright would put out lots of UV light. But even so, fly-bys that close would be very rare, but we would still be more likely to be cooked by a large star than orbitally perturbed by one. Smaller stars would need to fly much closer to have an effect, but smaller stars are also much more common.
Outer planets would be more vulnerable and oort cloud objects even more so, to near fly-bys and orbital perturbations, but again, that kind of near fly-by wouldn't happen often.
The following is multiple choice question (with options) to answer.
the closest star to our planet delivers solar energy to the planet | [
"this is truth",
"all of these",
"unknown",
"maybe"
] | A | the solar system contains the moon |
OpenBookQA | OpenBookQA-2943 | amateur-observing, binoculars
Title: How do I prevent or reduce shake when observing with binoculars? I have some 16 x 50 binoculars that my parents bought me years ago. Recently I have tried to do some basic lunar and planetary observations with them but I am seriously struggling with shaking. This was most noticeable tonight while attempting to observe the ISS.
While I accept that keeping the image of a moving target stable is going to be next to impossible, I would like to know how I could reduce my shaking while observing the moon and other objects.
Is anyone able to provide some simple techniques to reduce shaking? Don't hold the binoculars in your hands. Humans are made of meat. wobbly wobbly meat. There's apparently devices that let you mount binoculars on tripods - (this google search would be a start). Those and a tripod would probably be helpful in decreasing shake.
I suppose it would affect mobility a little but that's a tradeoff.
The following is multiple choice question (with options) to answer.
A woman looking through binoculars is watching something | [
"distant",
"near",
"close",
"beside her"
] | A | binoculars are used for observing distant objects |
OpenBookQA | OpenBookQA-2944 | thermodynamics, water
Title: Energy efficiency: better to heat hot tub constantly or twice a day for a longer period? I've got a hot tub in my garden with 1,500 litres of water in it and the target temperature is 38° centigrade.
The tub has two operating modes:
Economy: circulate water twice for 3 hours within 24 hours (at 4AM and 4PM). While circulating, heat if necessary.
Standard: same circulation but heat whenever temperature is dropping below 38°
Outside temperatures over here very between -15° at night (winter) and all the way up to +35° during the day (summer).
Usage of the hot tub is typically during the evening hours, the rest of the time the tub is covered with an insulated lid.
I observed that on warm days the economy mode consumes considerably less energy but I wonder if that will be true for colder days too and I would like to understand why this is the case.
I understand that the same amount of energy is needed to heat water, no matter how it's done. But isn't hotter water cooling down faster than cooler water? Does that have an impact on the decision of the mode?
Is it right that in an ideal world (which we don't live in), both modes should use exactly the same amount of power? From your description, it sounds like "standard mode" keeps the water always at approximately 38 degrees, whereas "economy mode" lets the water get cooler than this often.
When the water is cooler than 38 degrees, there'll be less conduction out of the pool, as the temperature differential between the water and the surroundings is lower. Less heat loss means less heat that you have to pay to add.
So, unsurprisingly, "economy mode" will work out cheaper for you than "standard mode".
The following is multiple choice question (with options) to answer.
Taking shorter showers is a great way to conserve | [
"H2O",
"gasoline",
"sunshine",
"electricity"
] | A | An example of conservation is avoiding waste |
OpenBookQA | OpenBookQA-2945 | inorganic-chemistry, experimental-chemistry
Title: Proper disposal of calcium hydride/calcium hydroxide I had probably 2-3 grams of calcium hydride leftover in a schlenk flask from predrying a distillation of benzyl chloride. For the disposal, I diluted the flask contents in about 30mL isopropanol and then, over a water bath (flask open but under heavy stream of argon), added distilled water every few minutes until well after the bubbling had stopped, which I assumed was exothermic evolution of hydrogen gas. I also thought any leftover benzyl chloride would just make trace toluene, benzyl hydroxide, and calcium chloride.
I then figured the milky-white solution was okay to pour down the sink with lots of water running and removed about half of it in this manner, although I noticed a brief but strong smell from the vapors as I did so and stopped. I checked and noticed some sites place it into a basic waste container. Was it a mistake to pour down the sink? I thought limewater would be harmless with enough water. Were there any other errors in this process? I may have to repeat this in the future with calcium hydride again or phosphorous pentoxide (seen various methods on P$_2$O$_4$, but one mentioned sink disposal as well). The safest way to get rid of calcium hydride is to pour over ice. The water quenches the reagent itself, with the ice helping to control the exotherm (if you just add water, a lot of heat and gas is liberated, having a tendency to spray hot chemicals over the whole hood).
Once everythings quenched, it's helpful to add some hydrochloric acid before disposing of down the sink to prevent it clogging the drains.
Note that whilst clean calcium hydride is safe (once quenched) to be disposed of via the normal drainage, you must ensure any chemicals are washed off first (hexane works well), especially odorous things such as amines which you may have been drying with the calcium hydride.
The following is multiple choice question (with options) to answer.
Which is likely to still be in water after treatment? | [
"feces",
"dirt",
"harmless dissolved rocks",
"mercury"
] | C | treating water is used to remove harmful substances before drinking |
OpenBookQA | OpenBookQA-2946 | 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.
Mechanical weathering is a end result of a | [
"wind turbines",
"solar panel",
"shad tree mechanic",
"giant ice river"
] | D | a glacier causes mechanical weathering |
OpenBookQA | OpenBookQA-2947 | forces, gravity, velocity
Title: Working of force of gravitation on the objects moving at the speed comparable to the speed of light If two clamped objects of mass m starts moving at the speed comparable to the speed of light.Will the gravitational force between them increase?
$$
m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}
$$
This formula says that the mass of a body will increase as it's speed increases.
$$
F_g=\frac{G\,m_1\,m_2}{r^2}
$$
If I take mass of each (clamped) body as m and a if I draw a graph by substituting the masses at the high velocity into the Newton's laws of gravitation,
I get a graph like this
: The answer is no, it won't.
Rather than give some detailed bit of maths to explain why this is, I'll give a more general argument which you can use to answer not only this question but any similar question.
The argument is this: consider yourself as an ant sitting on one of the masses (an ant so you don't perturb the forces very much). You have in your hand (claw?) a bit of paper on which are written two conflicting statements:
'your speed is $0$';
'your speed is $0.97c$'.
You now need to tell me which of these statements is true: what experiment can you do to answer this question?
Well the answer is, of course, that there is no experiment that you can do which will distinguish between these two statements. And, since that is the case, there can be no difference in the force experienced by the masses, from your point of view.
This sounds like a trite answer, but it's not: this trick of noticing that there is no possible observational way of distinguishing between two situations which are claimed to be different, and so they are not different is absolutely critical to understanding relativity, and is a very powerful tool.
The following is multiple choice question (with options) to answer.
the gravitational pull between two objects increases as they are | [
"spun around",
"brought together",
"exposed to light",
"moved apart"
] | B | as distance from an object decreases , the the pull of gravity on that object increases |
OpenBookQA | OpenBookQA-2948 | homework-and-exercises, kinematics, acceleration, speed
Title: Initial speed in homework problem This is a homework question. I tried to solve it, but failed.
I had to translate this question, so please forgive me if it is poorly worded.
In this question you can ignore the atmospheric effects.
A certain bird dives down 28 meters towards the sea to catch a fish. When it reaches the surface of the water, its speed is 100 km/h. However, it could never have reached 100 km/h in 28 meters, it needs a starting speed. What is the initial speed of the bird?
The acceleration is 9.8 m/s
The distance is 28 m
The final speed is 100 km/h, which is approximately 27.8 m/s
I figured I'd use these two formulas to figure out how much the bird accelerates in 28 m and subtract that from the final speed.
s = 1/2 * a * t^2
v = a * t
This did not work. The answer should be 15m/s. What have I done wrong? Here are the steps you want to take. We need to find $v_0$. The equations are
$$v_t = v_0 + g\cdot t\\
y_t = y_0 + v_0 t + \frac12 g t^2$$
Two equations, two unknowns. Eliminate $t$, then solve for $v_0$
(Note that I use a Y axis that increases as you go down - just saves thinking about the sign of $g$).
Alternatively you can use conservation of energy. You have the change in potential energy, and the final kinetic energy. This allows you to calculate the initial kinetic energy. In other words
$$\frac12 m v_0^2 + m g h = \frac12 m v_f^2$$
The following is multiple choice question (with options) to answer.
If a bird is moving through the sky, someone wanting to know the speed would | [
"speedily enjoy viewing",
"observe quickness",
"watch slowly",
"look away"
] | B | speed is a measure of how fast an object is moving |
OpenBookQA | OpenBookQA-2949 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is the most accurate statement? | [
"octopuses avoid sharks by blinding them with a dark substance",
"octopuses avoid scorpions using ink",
"octopuses avoid sharks using powerful claws",
"octopuses avoid scorpions by eating them"
] | A | ink is used for hiding from predators by octopuses |
OpenBookQA | OpenBookQA-2950 | Wisconsin Wildflowers Yellow, Adaptability Culture In Organizations, Tree Of Savior Hunting Grounds 2020, 2 Timothy 2:16 Kjv, Aristolochia Florida Native, Best Grass For Goats In The Philippines, Seymour Duncan Sh2 Bridge,
The following is multiple choice question (with options) to answer.
Redwoods are supported by | [
"donations from the environmental protection agency",
"very large and thick trunks",
"twenty chainsaw wielding psychopaths",
"industrial plants near the ocean"
] | B | a trunk is a source of support for a tree |
OpenBookQA | OpenBookQA-2951 | volcanology, volcanic-hazard, volcanic-eruption
Title: Would a Yellowstone eruption destroy global agriculture? Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither am I.)
Is that accurate?
Are there reasonable scenarios (i.e., not this) worked out for the effects of a supervolcano eruption?
I did see this question, where one of the commenters points out that such an event would be unprecedented, so our ability to predict is limited, but I'm still curious about whatever we do know at this stage. An eruption of the Yellowstone super volcano would cause agricultural disaster over a very large area. Its global effect would be significant, but not totally devastating.
The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.
But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.
Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.
Yellowstone last erupted 174 000 years ago, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.
The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is 660 ft. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.
The following is multiple choice question (with options) to answer.
A series of horrible earthquakes can effect deer populations by forcing | [
"relocation",
"planting seeds",
"breeding",
"studying"
] | A | natural disasters can cause animals to leave an environment |
OpenBookQA | OpenBookQA-2952 | geophysics, climate-change, climate-models
What changes with Earths precession is the position of the stars. The sky will shift depending on where Earth is in it's 22,000 year wobble. Similarly, the North star won't always be the North star. The night sky will look shifted by about 46 degrees in 11,000 years (some of the stars will have moved over that time-frame as well, but lets ignore that for now).
You've herd the term "Age of Aquarius". The astrological ages each last about 1,800-2,000 years, and the cycle of 12 ages corresponds to Earth's 22,000 year wobble. Note, that article says 25,860 years and your quoted 22,000 years. The solar system also wobbles, so how those wobbles add up can give different estimates. If you use 22,000 or 25,860 or 25,771 or 26,000 or 23,000 on average, the different numbers don't change the answer to this question. This explains the variation in the numbers used.
The following is multiple choice question (with options) to answer.
Due to the wobble of the earth it has four different | [
"visitors",
"locations",
"time zones",
"seasons"
] | D | each season occurs once per year |
OpenBookQA | OpenBookQA-2953 | humidity, water-vapour
Title: Water vapor content versus specific humidity I am wondering the difference between water vapor content and specific humidity to determine the moisture availability in the atmosphere. Which one is more acceptable variable to determine the moisture availability in the atmosphere?
I need to show the moisture availability in the atmosphere in my study. So should I explain it through water vapor content or through specific humidity? I will explain the rainfall deficiency over a region For a study relating to rainfall, I would be inclined to look at total column water vapour (TCWV), also known as integrated water vapour (IWV) or precipitable water. They're all (more or less) the same thing.
The company Remote Sensing Systems describes it as:
Total column water vapor is a measure of the total gaseous water contained in a vertical column of atmosphere. It is quite different from the more familiar relative humidity, which is the amount of water vapor in air relative to the amount of water vapor the air is capable of holding. Atmospheric water vapor is the absolute amount of water dissolved in air. When measured in linear units (millimeters, mm), it is the height (or depth) the water would occupy if the vapor were condensed into liquid and spread evenly across the column. Using the density of water, we can also report water vapor in kg/m2 = 1 mm or g/cm2 = 10 mm.
For rain to form, clouds need to form first. Clouds need cloud condensation nuclei, but crucially, for clouds to form, the water vapour partial pressure needs to reach the saturation vapour pressure. The latter is strongly dependent on temperature (Clausius-Clapeyron relation), so a profile of relative humidity is not the most directly useful quantity. The total column water vapour describes how much liquid water might form, which is why it is sometimes even described as precipitable water.
You can get this product either from reanalysis (like ERA-5) or retrieved from hyperspectral infrared sounders, such as IASI, AIRS, or CrIS. Depending on where and when in the world you're looking at, there may also exist products from geostationary instruments.
The following is multiple choice question (with options) to answer.
Which is likely water vapor? | [
"a dog",
"a cat",
"a rat",
"puffy white fliers"
] | D | water vapor is found in the atmosphere |
OpenBookQA | OpenBookQA-2954 | homework, reproduction, allele
Title: Albinism inheritance problem: what are the father's alleles if he got an albino kid?
Albinism is caused by a recessive gen "c". A normal man marries an
albino woman. The first son happened to be albino. What are the
possible phenotypes of the parents? What is the chance that their
other kids will be albino?
Alright, since "c" is recessive and the woman is albino, then the woman must be "c c" right? And since the son is albino, he must be "c c" too. Hence the father must have at least one "c". But since he is normal, then the other allele must NOT be "c" too (otherwise he would be albino).
My question is, when writing the Mendel table, how do I express that allele of the father (the one that is not "c")?
$$\begin{bmatrix} & c & c\\
? & ?c & ?c\\
c & cc & cc\end{bmatrix}$$
I marked it with $?$ because I'm not sure what to put there. My first thought was "well, it could be a capital C I guess..." - but that doesn't sound right to me. A capital C would mean there is a dominant albinism allele (but I am told that albinism is recessive only...)
I can see clearly that there is a 50-50 chance of having albino kids. I just don't know how to draw that inheritance table. Super oober short answer: The father is Cc, the mother is cc, there is a 50% chance the children will be albino (as you predicted).
An explination on Mendelian genetics:
First let's look at (what a lot of people consider) the normal Mendel table from here:
The following is multiple choice question (with options) to answer.
The color of what is an inherited characteristic? | [
"vision organ",
"wallpaper",
"blood",
"dirt"
] | A | eye color is an inherited characteristic |
OpenBookQA | OpenBookQA-2955 | Note:
Depending on where, and how frequently, you round during this function, your answers may be off a few cents in either direction. Try rounding as few times as possible in order to increase the accuracy of your result.
The following is multiple choice question (with options) to answer.
Which of the following is most accurate? | [
"humans can build bombs to harness hydropower",
"dams are a means of reducing reliance on oil",
"humans can build skyscapers to harness hydropower",
"humans cannot build dams to harness hydropower"
] | B | hydropower is when falling water produces electricity |
OpenBookQA | OpenBookQA-2956 | hydrology, mountains, rivers
Title: Why do rivers have 'wells' in mountains? Why/how can rivers have sources in places high above the sea level? The presence of water underground has nothing to do with sea level in mountainous country.
When rain fails on a mountain, or snow falls on a mountain and the snow eventually melts, the water from the rain or snow melt mostly travels downhill via rivers to the sea.
In getting to a river some of the water will fall on the ground. In places where the ground is covered by soil, water can travel through the soil via the pore spaces between the grains of soil. Similarly if porous rock, such as sandstone lies beneath the soil water can travel through the pores in the rock.
If a layer of impervious rock lies under the porous rock or soil, the water cannot move downwards, due to gravity, any further. This can lead to water accumulating in the soil or porous rock and saturating the soil or rock. In such situations an aquifer can form. The top of the saturated zone in an aquifer is called a water table.
The ground beneath a river is saturated and the surface of the river shows the water table exposed to atmosphere. Thus in mountainous regions the ground beneath rivers will be saturated and capable of supporting a well developed from the bank of a river.
The following is multiple choice question (with options) to answer.
If a hill has a sharp decline on a side, water will first run down | [
"a flat edge",
"sharpest side",
"everywhere",
"a softer side"
] | B | water flows down a slope |
OpenBookQA | OpenBookQA-2957 | organic-chemistry
It is highly unlikely that one of the $\mathrm{X1}$ mechanisms happen on the primary chlorine due to the very badly stabilised intermediate primary carbocation we would need, highly unlikely for an $\mathrm{S_N2}$ reaction to proceed on the tertiary chlorine due to steric hindrance (especially since a primary one is available) and moderately unlikely (but not impossible) for $\mathrm{E2}$ to happen on the tertiary chlorine.
We thus need to consider:
How good is the leaving group (influences everything strongly except for $\mathrm{E2}$)?[2]
How strong is a base possibly present in solution (influences which elimination reaction can happen and how well)?[3]
How good is our nucleophile (influences the probability of $\mathrm{S_N2}$ most)?[4]
The following is multiple choice question (with options) to answer.
Which would likely be a chemical reaction | [
"an ember",
"oil and water",
"steel and iron",
"play dog"
] | A | chemical reactions cause chemical change |
OpenBookQA | OpenBookQA-2958 | electromagnetism, computer
As for MRI scanners, there's a reason why the first and last thing they check, when you go and have an MRI scan, is that you have nothing potentially ferromagnetic on or in your body. The reason is that anything ferromagnetic that gets too close to an active MRI magnet is likely the get torn off your hands and violently slammed against the magnet. This has been known to happen to pretty much any wholly or partially ferromagnetic object you'd care to imagine, from wheelchairs, office chairs and floor polishers to scissors, oxygen bottles (which killed a small child) and even pistols (which, yes, went off when it hit the scanner).
So, let's imagine what'll happen to your hapless policeman, as he's walking towards the magnetized door carrying a stack of hard drives. The first thing he's likely to notice, while still several meters away, is that something's pulling at the drives he's carrying (since they have a lot of ferromagnetic metal in the casing, and even some pretty strong magnets inside). If he's not careful, the drives might slip out of his hands and fly through the air towards the door, slamming against the door jamb with enormous force (and, yes, likely getting pretty well wiped in the process).
The next thing he might notice, if that's not enough to make him stay well away from the door, is that the same force is also tugging at his badge, gun, zipper, belt buckle, the screwdriver in his pocket that he used to open the servers and extract the hard drives, and anything else metallic that he might have on him. If he's not careful, and keeps approaching the door, those items might either get pulled out of his pockets, or they might simply get drawn to the door and pull him along with them. If he's lucky, the only thing getting pinched between the door and the objects is his clothing. If he's not...
The following is multiple choice question (with options) to answer.
Before their trip to the Amazon Bill and Jane had sharp metal objects stuck into their arms by a doctor. | [
"they were getting ice water injected so they would stay cool in the Amazon",
"they wanted to avoid contracting something",
"aliens performed experiments on them",
"they wanted to catch the flu"
] | B | vaccines can help prevent illness |
OpenBookQA | OpenBookQA-2959 | thermodynamics, visible-light, temperature, thermal-radiation, biology
Title: Why are people dark skinned in hotter areas despite dark colour absorbing the most heat? I’m not sure if the reason is in the field of biology or more towards physics but as my reasoning is based on the physics part being that perfectly black bodies are perfect absorbers of heat and light while white is a perfect reflector but we have darker skinned humans near equator and lighter skinned people (as well as animals like polar bears) near the poles, I’ve posted it on physics stackexchange. Also, if the answer is based on the biology of animals and this should belong to biology stack exchange, feel free to let me know. This is a bio question.
The biggest threat to fitness is not lack of cooling, but damage from UV rays. A pigment in black (actually all skin to differing degrees) absorbs the UV so that skin cells don't.
Fair skinned people, from higher latitudes, have another risk to their fitness which is a lack of vitamin D which is produced by the skin when exposed to UV.
As a result of this, fair skinned people in the tropics get more skin cancer than otherwise, and dark people are more likely to have a vitamin D deficiency if far from the tropics.
The following is multiple choice question (with options) to answer.
Which likely would live in the hottest environment? | [
"bear",
"penguin",
"moose",
"scorpion"
] | D | warm-weather organisms live in warm climates |
OpenBookQA | OpenBookQA-2960 | polymers, plastics
Title: What is Polymer Environmental Resin (PER)? I'm no chemist and I probably wouldn't understand any technical answer but...
I'm investigating the environmental impacts of various materials as compared to PVC and this is one that crops up regularly as a more environmental alternative.
Unfortunately there does not seem to be any authoritative information on the web concerning this material.
I'm beginning to think that this is a green-washing propaganda move by the phthalate/heavy metal free PVC industry as a move avoid mentioning PVC in product advertising.
Anyway I would welcome any information on what exactly PER is and what it is made from.
Thank you. PER is essentially PVC which has been plasticized and stabilized with acetyl tributyl citrate, instead of the host of phthalate-based plasticizers such as bis-diethylhexyl phthalate (DEHP) whose endocrine-disrupting properties give PVC its well-deserved bad reputation.
Citrate salts tend to be readily water soluble, and therefore this material is touted to be more biodegradeable than phthalate-plasticized PVC. I certainly cannot find any information to refute that claim. ATBC will further degrade into other acetates and butyrates, most of which are relatively common and harmless in the environment (though butyl compounds are infamously stinky; butyric acid is a favorite less-lethal offensive-odor weapon of law enforcement and groups like the Sea Shepherds). All PVC will eventually degrade as the plasticizer leaches out over time, unlike other types of plastics that are so ridiculously inert they'll likely be the fossils of our modern era, but again, the phthalates just aren't a great idea to have in the environment.
The following is multiple choice question (with options) to answer.
Recycling which of the following has a positive impact on the environment? | [
"acquired earth materials",
"rocks",
"car pools",
"bees"
] | A | recyclable means a material can be recycled |
OpenBookQA | OpenBookQA-2961 | zoology, entomology, ant, sociality
Giving some reasons for their existence:
To what use is all this effort? Not, it seems, as protection from the elements. The earthworks fall apart in rain, and disintegrate when the earth is dry. Arcades are thin enough to puncture with a tap of a finger, which means a route is weatherproof only when it travels through an underground tunnel, perhaps dug and then abandoned by other animals. Alternatively, near the nest the ants may make a subterranean route of their own: over time, construction crews can scratch away so much soil from the trail surface that the highway sinks from view, at which point the ants seem to be able to construct a thicker, rainproof cover that becomes flush with the surrounding land.
The main function of this relentless building is defense. Because trunk trails extend for dozen of meters, they travel through territory controlled by other ant species. Marauder ants must therefore be organized to protect the trunk trails from aggressive neighbors or even from hapless passerby such as the Diacamma.(...)
...after an arcade has been completed[,] the Diacamma workers could now walk over the trunk trail, blissfully ignorant of the industry below them. if a trail should sink underground, it is as protected as a passage in an army bunker, safe even from human footfalls.
Bulwarks constructed over trails and provisions prevent battles among competing marauder ant colonies as well. Where they are absent, combat can last a day and engage thousands of minor workers, which pour along the line of contact between the armies.
The following is multiple choice question (with options) to answer.
Animal rights activists are against people going into forests to live and build things because that will lead to animals homes being | [
"shoes",
"enabled",
"TV",
"taken away"
] | D | humans moving into an environment usually causes native species to lose their habitats |
OpenBookQA | OpenBookQA-2962 | newtonian-mechanics, energy, everyday-life, biophysics
Running involves more and varied movements, it's a very different gait. It is definitely not just the same movement as walking but faster. Some of those movements are vertical, or relate to jumping, some have shock absorption components and relate to landing. Much of that extra energy is dissipated both ways - we use energy both to jump and to cushion and come to a halt on landing. We also accelerate our feet to match our ground speed and must slow them to zero each stride, then speed and lift the other way as well, not just rely on gravity and pendulum activity. The fact this is at extension and not at ground impact doesn't change anything. Again, energy is lost both ways. I'm also going to guess that it's harder to be efficient across a wider compared to narrower range of motions, therefore the wider range of movements and systems used in running means it's much more likely that efficiency varies considerably, according to biological subsystem or type of movement.
Human gross muscle motion energy handling/metabolism is not efficient and doesn't behave like an ideal object. We have multiple energy pathways, and switch between them according to need. This happens less with walking, more with vigorous exercise like running. The "emergency" or "sustained activity" energy cycle our bodies switch to, when running, is less efficient - if it was more efficient it would probably have evolved as our primary not our fallback. And of course many biochemical reactions and body responses just aren't linear; they also may have min/max rates or durations.
The following is multiple choice question (with options) to answer.
If a body has nutriment running through all of it, then the thing responsible for moving it around is | [
"arteries",
"lungs",
"knees",
"eyes"
] | A | veins transport nutrients throughout the body |
OpenBookQA | OpenBookQA-2963 | zoology, mathematical-models, software, imaging
Title: What would it take to recognize a deer by its photo? I am trying to recognize a deer by its antlers or any other means.
Elaborating:
I was hoping to use their antlers to recognize them but I have heard that most deers shed their antlers every year so it would be difficult to recognize it from the last year's photo unless these antlers retain the same pattern every year.
If not the antlers, what other characteristics should I be looking for?
Is there any software that can help me in recognizing a deer? There is a lot of variation in how and when deer shed their antlers. In most arctic and temperate-zone species, antler growth and shedding is annual, and is controlled by the length of daylight. In tropical species, antlers may be shed at any time of year, and in some species such as the sambar, antlers last several years. Some equatorial deer never shed their antlers.
The horns change every year and, especially, increase the number of branches (and consequently, change their shape). You can't recognize them by antlers, but by other features, such as color of the hair or the lineaments. Like us, animals have individual morphological differences that are recognizable and listable.
Biologists specializing in studies of particular animal species not only take photos, but also make drawings and write descriptions of behavior, to identify individuals within herds.
An optical examination, however, of the subject through drawings and photos (and if possible, direct observation), is more useful than a PC program. This involves identifying particular similarities and equalities that are not "identical". This is possible to do visually on a large (but limited) number of specimens. The human eye is the best computer.
The following is multiple choice question (with options) to answer.
Deer are most likely to give a wide berth to a | [
"personal garden",
"field of alfalfa",
"cool mountain stream",
"decomposing body"
] | D | most animals avoid bad odors |
OpenBookQA | OpenBookQA-2964 | plant-anatomy
Title: Are bryophyte sporangia multicellular? My research on the matter can be summarized in a sentence: "It [sporangium] can be composed of a single cell or can be multicellular" (Source: https://en.wikipedia.org/wiki/Sporangium). Yet there shouldn't be a reply placed between "They are" and "They aren't" test options, speaking of "Are bryophyte sporangia multicellular?". A link to the source where I could ascertain whether the bryophyte sporangia is multicellular (if I could ascertain) is highly appreciated. In Embryophyta (land plants), including bryophytes, the sporangium is usually a multicellular structure.
Perhaps you meant to ask about the number of spore mother cells (SMCs) in each sporangium? That varies across groups. In bryophytes, each sporangium has many SMCs, and accordingly produces a large number of spores. (Contrast this with angiosperms, where a megasporangium [called an ovule] has only one megaspore mother cell.)
References and further reading:
https://courses.lumenlearning.com/boundless-biology/chapter/bryophytes/
https://www.britannica.com/science/plant-development
Image attribution:
By LadyofHats. (Public domain;
https://commons.wikimedia.org/wiki/File:Hornwort_structures.jpg)
The following is multiple choice question (with options) to answer.
A thing which ferns have in endless supply when expanding is | [
"oil",
"dirt",
"darkness",
"castor"
] | B | soil is a renewable resource for growing plants |
OpenBookQA | OpenBookQA-2965 | evolution, zoology, taxonomy, phylogenetics
The apomorphy that defines the tetrapods is "paired limbs". You have Amphibia to the left and Amniota to the right, whose apomorphy is " egg with extraembrionic membranes". Inside them, you have Reptilia, whose apomorphies are "skull with upper and lower fenestra and beta-keratin in epidermis". Turtles came from an ancestor with these characteristics. So, turtles belong to the monophyletic group of "Reptiles".
Post scriptum: You wrote that "turtles (specifically sea turtles) live on both land and water, very much like amphibians". Just a curiosity: the reason why sea turtles leave the water (sea) from time to time shows exactly that they are not amphibians! Amphibians, being non-amniotes, have eggs that survive under water (actually, with few exceptions, they need to be under water). Turtles, on the other hand, are amniotes, and the amniotic egg cannot be laid under water. That's why the turtles have to leave the water to lay eggs: because, contrary to the amphibians, they cannot lay eggs under water.
The following is multiple choice question (with options) to answer.
Amphibians undergo changes in structure of being in that | [
"salamanders can regrow their tails",
"salamanders can lose their tails",
"frogs can breathe air and water",
"they begin as a different looking being"
] | D | shale can be metamorphosed into slate by increased pressure |
OpenBookQA | OpenBookQA-2966 | c++, game
outfile << "Room:" << endl;
outfile << "5 2" << endl;
outfile << "country_10" << endl;
outfile << "You are in the countryside, to the north is the road & to the south is a large hill." << endl;
outfile << "null" << endl;
outfile << "Maybe go back to the road?" << endl;
outfile << "0" << endl;
outfile << "Room:" << endl;
outfile << "5 3" << endl;
outfile << "hill" << endl;
outfile << "After a brisk climb to the top of the hill, you finally look around you. On the top of the hill is a tall oak tree, providing much needed shade from the summer heat. From the tree you can see a town to the north-east and a hut to the south-east. There is also a path leading to the hut from the road, it passes by right at the foot of the hill." << endl;
outfile << "null" << endl;
outfile << "Head for the town" << endl;
outfile << "0" << endl;
outfile << "Room:" << endl;
outfile << "5 4" << endl;
outfile << "country_7" << endl;
outfile << "You are in the countryside, to the north is a large hill." << endl;
outfile << "null" << endl;
outfile << "Maybe go back to the road?" << endl;
outfile << "0" << endl;
The following is multiple choice question (with options) to answer.
Dirt is moved from one part of a forest to another, and travels across a field to get there. The movement is | [
"caused by gusts",
"due to clouds",
"made by trees",
"because of litter"
] | A | soil erosion is when wind move soil from environments |
OpenBookQA | OpenBookQA-2967 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
A compass uses natural magnetism so it works only because | [
"the world is positive",
"the world is wet",
"the Earth is fat",
"the Earth yanks it"
] | D | natural magnetism is used for pointing north by a compass |
OpenBookQA | OpenBookQA-2968 | thermodynamics, energy, temperature, estimation
Title: What would happen if a 10-kg cube of iron, at a temperature close to 0 kelvin, suddenly appeared in your living room? What would be the effect of placing an object that cold in an environment that warm? Would the room just get a little colder? Would it kill everyone in the room like some kind of cold bomb? What would happen?
Don't think about how the cube got there, or the air which it would displace. Nothing overly dramatic, though it would be cool to look at. The cube would very quickly become covered by a layer of nitrogen/oxygen ice as the air which came into contact with it froze. Further away, you'd see condensation of water vapor into wispy clouds, which would swirl around the block due to the air currents generated by the sudden pressure drop.
Other than that, as long as you aren't in immediate thermal contact with the block, you wouldn't notice much other than that the room cools down. Here's a video I took of a vacuum can that was just removed from a dewar of liquid helium at 4 kelvin. It's maybe 5 kg of copper, not 10 kg of lead, but I'd say that's close enough to get the idea.
You can see one of my coworkers climbing down into a pit below it; he had to be careful not to bump his head on it, which would have really ruined his day, but there was no fatal cold bomb :)
The following is multiple choice question (with options) to answer.
Lucy came in from the cold and can's stop shivering. It might help her to sit near | [
"a running boiler",
"an iceberg",
"a wet towel",
"a sofa"
] | A | a hot substance is a source of heat |
OpenBookQA | OpenBookQA-2969 | 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.
Camouflage can be used by animals for hunting | [
"trees",
"meals",
"air",
"water"
] | B | camouflage can be used for hunting for prey |
OpenBookQA | OpenBookQA-2970 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
Hunting any kind of animal will eventually cause that species population numbers to | [
"go down",
"phone number",
"atomic number",
"egg shell number"
] | A | harming an animal species causes that animal 's population to decrease |
OpenBookQA | OpenBookQA-2971 | I suspect that what you actually meant was that there are half as many nodes of height $m+1$ as there are of height $m$. This is the correct observation to make, so long as $m$ is less than the height of the tree (which I take to be a hidden assumption). By inductive hypothesis, there are $$\left\lceil\frac{n}{2^{m+1}}\right\rceil$$ nodes of height $m$, and so by our observation, there are $$\frac12\cdot\left\lceil\frac{n}{2^{m+1}}\right\rceil$$ nodes of height $m+1$. Your task, then, is to show that $$\frac12\cdot\left\lceil\frac{n}{2^{m+1}}\right\rceil=\left\lceil\frac{n}{2^{m+2}}\right\rceil,$$ or equivalently, $$\left\lceil\frac{n}{2^{m+1}}\right\rceil=2\cdot\left\lceil\frac{n}{2^{m+2}}\right\rceil.\tag{&}$$
The following is multiple choice question (with options) to answer.
A new walnut tree sprouted up 200 feet away from the nearest other walnut tree. | [
"a walnut was carried to the new spot on a light breeze",
"a walnut was picked and carried into a house",
"all the walnuts were gathered by a walnut farmer",
"a squirrel was forgetful"
] | D | In the tree reproduction process a squirrel has the role of seed disperser |
OpenBookQA | OpenBookQA-2972 | biochemistry, neuroscience, neurophysiology, vision, eyes
*Personally, I find it hard to grasp just how large the difference in Illuminance (and hence photon numbers) is for example between day and night. See here for a comparison. As you can see, our visual system has to deal with an enormous dynamical range of illuminance. The fact that we usually don't even think about these differences in light intensities in everday live is testament to how fantastic our visual system is in dynamically adapting to the huge differences in input.
The following is multiple choice question (with options) to answer.
Seeing in the darkest of nights with an LED torch necessitates using | [
"batteries",
"the movie industry",
"chemical romance",
"snow"
] | A | a flashlight converts chemical energy into light energy |
OpenBookQA | OpenBookQA-2973 | Note: Before you can calculate how many plants will be required to fill a given area you'll need to first determine the total square feet of the planting bed. Many online calculators use this formula: $$Total\,number\,of\,plants = {Area\,of\,garden \over Plant\,spacing^2}$$. Image Credit: Getty Images Calculating even spacing is an essential carpentry technique that you might need for things like fence pickets, railing balusters, or decking planks. How much food you need to eat everyday based off your weight, height, age, and activity. Hedges with plants 60cm apart "fill in" quicker than those planted 100cm apart but you get just as good a ⦠Get a Quote for. Planting fruit trees too close together causes them to shade each other and produce lower yields and lower quality fruit. Now simply choose one of these options and start planting! Area in Square Feet: Plant Spacing in Inches: Number of Trees in Bed: Calculate *Only enter one bed at a time, do not combine bed square footages and enter as one. Length Member Width ... Decimal Inch or Metric mm. Fill in any two fields and this tool will calculate the third field. The plant quantity calculator works out the area of the garden based on the measurements you provide (in metric or imperial units) using the formula: $$Area\,of\,garden = Length \times Width$$ Our calculator allows you to use both square and triangular patterns for the plants with equal coverage. This calculator figures seed spacing and population. Spacings Calculator Metric Never use a chart again! Our calculator allows you to use both square and triangular patterns for the plants with equal coverage. A Tree Spacing Calculator that will calculate the number of trees per acre and spacing between trees and tree rows. ... Calc # of plants needed in a rectangular and triangular grid from area and spacing between plants. If you desire to only plant the perimeter, click the checkbox "Perimeter only". Toro dripline calculator. feet) x (Spacing Multiplier) = Number of plants needed (Area is 2 feet by 25 feet = 50 sq. There are two distance requirements for the calculation; the distance between tree rows and the distance between the trees themselves. Next, to calculate the
The following is multiple choice question (with options) to answer.
if a farmer needed the plants in the garden to multiply, which of these could help? | [
"introduction of cactus plants",
"introduction of grasshoppers to the garden",
"introduction of Bombyliidae to the garden",
"introduction of weevils in the garden"
] | C | plant reproduction requires pollination |
OpenBookQA | OpenBookQA-2974 | image-processing
Title: High Dimensional Spaces for Images Can anyone explain why pictures are not considered 2D, but rather high dimensional? Especially with regards to CV and AI. From one perspective, a picture is a 2D image, because it has height and width.
But from a machine learning perspective, we can think of a picture as a point in a high-dimensional space. In particular, suppose we have a greyscale picture that is $m\times n$ pixels, i.e., $m$ pixels wide and $n$ pixels high. Then there are a total of $mn$ pixels in the image. Each pixel has a greyscale intensity, which we can think of as a real number in the interval $[0,1]$. Therefore, we can think of the picture as being a collection of $mn$ real numbers. In other words, the picture can be treated as a $mn$-dimensional vector -- as an element of $\mathbb{R}^{mn}$. Thus, any particular picture can be thought of as an element of a high-dimensional space.
The latter perspective arises natural for some machine learning approaches to computer vision, e.g., where we feed the pixels of the image into the machine learning algorithm, where each pixel value is treated as a separate pixel.
(A color image can be thought of as an element of $\mathbb{R}^{3mn}$: for each pixel, we have three numbers, corresponding to the intensity in the red, green, and blue channels.)
The following is multiple choice question (with options) to answer.
High can be visually represented by | [
"valleys",
"mountains",
"basins",
"deep sea"
] | B | landslides often occur on mountains |
OpenBookQA | OpenBookQA-2975 | predators (y2) die of natural causes (Reaction 3). At the same time , a trio of coming-of-age Predators have arrived to collect the skulls of the aliens as trophies , and the humans are caught between a deadly battle between the Spectacular and decent Aliens/Predators movie set in Antarctica where a motley group takes on extraterrestrial monsters. In The Lotka Volterra Predator-prey Model, The Changes In The Predator Population Y And The Prey Population X Are Described By The Following Equations: Δxt=xt+1−xt=axt−bxtyt Δyt=yt+1−yt=cxtyt−dyt Write A Function Simulatepredatorprey (x,y, A,b,c,d, T) That Takes In The Initial Population This problem has been solved!. The main objective was to investigate the spatio-temporal pattern of diffusive prey-predator model and the emergence of irregular chaotic pattern as a result of prey-predator interaction. Eigenvalues and eigenvectors. This project results in a Lotka-Volterra model which simulates the dynamics of the predator-prey relationship. In this study, the approximate solutions of the predator–prey system with delay have been obtained by using the modified Chebyshev collocation method. To understand how predators optimize foraging strategies, extensive knowledge of predator behavior and prey distribution is needed. The number of predators is represented by y, the number of prey by x. Yang, Yong S. (This Malthus-type equation gives. a discrete time predator prey model specified by Neubert et al[9] which utilises the Ricker model to simulate prey growth. Open the first file for this module by typing on the Matlab command line: ppmodel1. 1 Introduction. If algae and plankton communities are threatened, the entire food web may change. In this work, we investigate numerically a system of partial differential equations that describes the interactions between populations of predators and preys. This paper investigates a dynamical predator-prey interaction model that incorporates: (a) hunting cooperation among predators; (b) Allee effect in prey. At the other extreme,. b) The rabbits eat grass and breed. function to be a Di erence sequence and study the convergence of the model. (5 stars rating will be given =). In the notes, the author
The following is multiple choice question (with options) to answer.
When the amount of food goes down, the amount of conflict between the organisms searching for it will | [
"nothing.",
"remain the same",
"go down",
"go up"
] | D | as the population of prey decreases , competition between predators will increase |
OpenBookQA | OpenBookQA-2976 | homework, reproduction, embryology
Title: Which process is needed to complete male reproductive development? In order to properly complete male reproductive development:
A. primordial germ cells must begin Meiosis I in utero.
B. Sertoli cells must produce testosterone.
C. Dihydrotestosterone must masculinize Wolffian duct derivatives
D. the paramesonephric ducts must degenerate
E. the metanephros must form the genital epithelium
My attempt: I think the answer is C because testosterone turns into DHT which then masculinzing the wolffian duct. Other people I am studying with claim the answer is D (which is true) except that I dont think the loss of the paramesonephric duct is needed to complete male repro development. Regarding option C:
Although it is correct that testosterone is converted into DHT, it is the former, not the latter, which is responsible for differentiation of the mesonephric (a.k.a. Wolffian) ducts:
Between 8 and 12 weeks, the initial secretion of testosterone stimulates mesonephric ducts to transform into a system of organs—the epididymis, vas deferens, and seminal vesicle—that connect the testes with the urethra.*
DHT (dihydrotestosterone) is produced in the Leydig cells by the 5α-Reductase enzyme. It is required for induction of the external male genitalia (urethra, penis, and scrotum) and prostate from the embryonic ureteral groove, and for testicular descent into scrotum.
Regarding option D:
Sertoli cells secrete Anti Müllerian Hormone (AMH), which causes degeneration of the müllerian (a.k.a. paramesonephric) ducts between weeks 8 and 10. It is normal to speak about degeneration of the müllerian ducts as a defining aspect of male embryology, and thus I believe answer D is correct. Your point is taken, however:
Nevertheless, small müllerian duct remnants can be detected in the adult male, including a small cap of tissue associated with the testis, called the appendix testis, and an expansion of the prostatic urethra, called the prostatic utricle.*
The following is multiple choice question (with options) to answer.
the presence of which of these is required for the formation of cavernous chambers? | [
"some carbonated soda",
"some carbon dioxide",
"some carbonic acid",
"carbon monoxide gas"
] | C | a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone |
OpenBookQA | OpenBookQA-2977 | entomology
Title: The death of Earthworm In rainy season when children sprinkle salt on earthworm ,it dies.But salt is not dangerous.We use it daily.Then why earthworm dies? It's because on the earth worm skin's special mucous. Acording to this article: Why do earthworms die when salt is sprinkled on them? the mucous makes moist to the worm's skin, which is vital for their survival. Moreover, the worms don't have a respiratory organs, like lungs, gills, etc. This means that Carbon Dioxide and other characterized as "dump" gases can not be exchanged with the Oxygen. But worms breath through their skin, with the help of these special mucous that are developed on its skin. If their skin dries out the result will be death, because the gas exchange will not last without the mucous help. Similarly, the circulatory system won't function, because its main role is to trade gasses with the cells via red blood cells.
What about salinity?
Salinity is a very important factor for the earthworms health, because high salinity destroy their valunable and sensitive skin and kills the mucous that in fact help the worm to "breathe". Low salt concentrations are very beneficial for the worm, because not only their mortarity level is increaced, there are size changes to the worm's body (noticeable bigger size).
Here are and some photos of a worm that its enviroment has low salinity and high salinity:
High salinity:
Low-to-medium salinity
Source: Why do earthworms die when salt is sprinkled on them?.
The following is multiple choice question (with options) to answer.
Annelida aide the earth by redepositing | [
"trees",
"nutrients",
"air",
"real estate"
] | B | decomposition increases the amount of nutrients in the soil |
OpenBookQA | OpenBookQA-2978 | geophysics, earth-history
Title: Impact Erosion Selectivity In Offloading Radioactive Material ref : https://science.ubc.ca/news/asteroid-impact-erosion-helped-make-earth-habitable
According to the theory of impact erosion, the early crust was presumably much hotter w/ radioactive isotopes (U & K, primarily) and thus less congenial for the later development of life. Asteroid bombardment - I suppose during the late heavy bombardment - then blew off a sufficient chunk of this material to lower net radioactivity in the crust.
Was this simply because beforehand for some reason there was an upward gradient of radioactivity in the primeval crust ? I'm at a loss to conceive a selective mechanism for this phenomenon. Any paleo-geologists in the house ? All the original research paper is saying is that there might be less radioactive elements in the silicate Earth (crust + mantle) than previously thought. And if there had been more of those elements, there would have been more internal heat, thus a different tectonic regime, a different volcanism, a different geodynamo, a different atmosphere... And maybe, maybe, these different conditions would have prevented the emergence of life.
Also, don't forget that even is uranium is dense, it doesn't "sink below the crust". The mantle is solid rock, uranium is trapped in the crystal lattice of minerals, but it is an incompatible element, meaning it will preferentially go into the melt when the mantle partially melt. These melts then rise by buoyancy and actually make the bulk of the continental crust. So it makes perfect sense that the crust is uranium-enriched and the mantle uranium-depleted. Then, if you remove some of this crust after its formation, you will indeed remove some radioactive elements compared to the original composition (I'm not saying it happened, but the model is perfectly logical).
The following is multiple choice question (with options) to answer.
Boulders are most likely to be reduced into fragments due to heat in a | [
"cereal bowl",
"ocean",
"desert",
"tundra"
] | C | being exposed to heat can cause erosion of rocks |
OpenBookQA | OpenBookQA-2979 | species-identification, botany
Weakley (2015) "Flora of the Southern and Mid-Atlantic States"
1 Leaflets 3, toothed, lobed, or entire; shrub or vine.
2 Fruits pubescent or papillose; leaflets entire, coarsely toothed, undulate, or round-lobed; lower surfaces of leaflets either velvety puberulent, sometimes becoming glabrate in age (T. pubescens) or glabrous (glabrescent or rarely pilose beneath) but with prominent tufts of tannish hairs present in the vein axils (T. radicans var. radicans).
3 Leaves sparsely pubescent (rarely pilose beneath), the apex and the lobes (if present) generally acute to acuminate; drupes papillose, scabrous or puberulent; plant a high-climbing vine or stoloniferous shrub; [of mesic, swampy, or dry habitats].......... T. radicans var. radicans
3 Leaves velvety puberulent (sometimes becoming glabrate in age), the apex and the lobes (if present) generally obtuse to broadly acute; drupes pubescent (becoming glabrate); plant a stoloniferous shrub; [of dry habitats, especially sandhills] ............. T. pubescens
2 Fruits glabrous (or very sparsely pubescent); leaflets coarsely toothed or notched (rarely entire); lower surfaces of leaflets glabrous to pubescent, but without tufts of tannish hairs in the vein axils.
The following is multiple choice question (with options) to answer.
Waxy leaves can be considered | [
"love",
"anger",
"happiness",
"clothes"
] | D | waxy leaves are used for storing water by some plants |
OpenBookQA | OpenBookQA-2980 | zoology, ethology
Title: Is there a term for tool use in animals? Is there a technical/scientific term that scientists use to refer to tool making abilities found in certain types of animals?
Reference http://en.wikipedia.org/wiki/Animal_cognition#Tool_and_weapon_use Having read this article on tool use in Chimpanzees in full, I am inclined to say that if such a term existed then either the article itself or the titles of any of the 30 articles referenced would have included it.
Searching a couple of online biological dictionaries and ethology sites hasn't yielded anything either, therefore until someone else points out that I'm missing the obvious I'd say you're free to coin the term yourself!
The following is multiple choice question (with options) to answer.
An example of tool use is | [
"mankind's closes relative using a stick to get ants out of a hole",
"a person throwing a hammer into a pool",
"a bird building a nest",
"someone looking at screwdrivers in a store"
] | A | An example of using tools is a chimpanzee digging for insects with a stick |
OpenBookQA | OpenBookQA-2981 | geophysics, plate-tectonics, earth-history, continent
Title: Why Do Supercontinents Form? It would seem, on the face of it, improbable that the continental land-masses would accumulate into a single composite, yet it has happened numerous times, and is expected to again in the future.
There must likely then be some aspect of plate tectonics which favors these arrangements.
Can anyone provide an explanation?
EDIT: This is not, as I see it, a duplicate of the 'What are the causes of the supercontinent cycle?' question. This question goes to what process drives the formation of any & all supercontinent formations, which I assert should be improbable, made more improbable by their recurrence, not so much the cycle itself. The other question did not address this more fundamental aspect, or in any case receive a pertinent account of its resolution. If anyone wants to engage on this, or doesn't see the distinction, please do so in the comments or a chat. I think the mechanisms that you're looking for are subduction, paired with the "stickiness" of continental crust.
The subduction of oceanic crust under continental crust inevitably creates a net movement of crustal material toward a continental plate. Any oceanic plate that is carrying continental material will therefore always drag that continent toward the continental plate that it is subducting underneath, always resulting in eventual collision.
If an oceanic plate has subduction occurring on both sides, the ocean will inevitably narrow until it closes, thereby causing the continental plates on either side to collide.
In every case, subduction inevitably pulls continents together.
Furthermore, once continental plates collide, they have a tendency to stick together for long periods of time, increasing the likelihood that all continental material will eventually accumulate there.
The following is multiple choice question (with options) to answer.
when the earth's plates grind against each other it can be detected with a | [
"tape measure",
"ruler",
"seismograph",
"geiger counter"
] | C | a seismograph is used for measuring the size of an earthquake |
OpenBookQA | OpenBookQA-2982 | star, universe, density, hypothetical
Title: Is there a star over my head? Say I'm standing up straight, and I draw a straight line from my core through the top of my head (perpendicular to the ground). What is the probability that that line intersects with a star?
EDIT: I'm not trying to exclude any stars. This should include stars which we've observed and stars which we haven't yet observed but can predict due to other things we've determined (like the overall star density of the universe). Also it should include all stars regardless of naked eye magnitude limit. Summary
There's a 1 in 500 billion chance you're standing under a star outside the Milky Way, a 1 in 3.3 billion chance you're standing under a Milky Way star, and a 1 in 184 thousand chance you're standing under the Sun right now.
Big, fat, stinking, Warning! I did my best to keep my math straight, but this is all stuff I just came up with. I make no guarantees it's completely accurate, but the numbers seem to pass the sanity check so I think we're good.
Caveat the First: The numbers for stars other than the Sun are based on data with a great deal of uncertainty, such as the number of stars in the universe and the average size of a star. The numbers above could easily be off by a factor of 10 in either direction, and are merely intended to give a rough idea of how empty space is.
Caveat the Second: The numbers for the Sun and the Milky Way are based on the assumption that you are standing (or floating) at a random point on Earth. Anyone outside the tropics will never have the Sun over their head. People in the northern hemisphere are more likely to have Milky Way stars over their head, with the best odds being people near 36.8° N, because at that latitude straight up passes through the galactic center once a day.26
Note: You can mostly ignore everything in this answer and just look up the solid angle of the Sun to get the same result. All the other stars are really far away and very spread out. The difference in solid angle subtended is five thousandths of a percent more when we add the rest of the universe to the Sun.
Background
Let's try to get a somewhat realistic, hard number. To do that, we'll need some assumptions.
The following is multiple choice question (with options) to answer.
if a spoon was placed outside under our closest star, what could happen to it? | [
"it would shrink smaller",
"it would feel warmer to touch",
"it would freeze over",
"it would become a gas"
] | B | absorbing sunlight causes objects to heat |
OpenBookQA | OpenBookQA-2983 | atmosphere, climate-change, thermodynamics, radiative-transfer
All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.
Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: Dubai construction alters local climate
Additional references
Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution
of global anthropogenic heat flux. Atmos. Oceanic
Sci. Lett., 5, 108–112.
The following is multiple choice question (with options) to answer.
Which event can lead to the human caused change of an environment? | [
"seasonal storms",
"annual flooding",
"natural woodland fires",
"clear cutting"
] | D | if the amount of available food and water decreases in an environment then animals may leave that environment to find food and water |
OpenBookQA | OpenBookQA-2984 | reproduction, evolutionary-game-theory
Title: Why don't all male animals kill a rejecting female? If a male animal is sure that the female animal will not reproduce with it, wouldn't it be mathematically optimal for the male to kill the female? (To ensure that no alleles of the "overreact-to-rejection" gene in other males can make use of the female as a reproductive resource)
I might be missing something very obvious here, but I can't seem to see why a gene for "kill-rejecting-potential-mate" wouldn't spread through the gene-pool. The simple answer is most animals females can fight back. Its similar to the reason male to male fighting often evolves to become more and more ritualized. Fighting is risky, and the closer in size and capabilities the fighters are, the riskier it becomes. Behavior that tends to get you injured for little to no benefit tend not to get passed on. and there is little to no benefit in killing females for a male. Plus a female who is alive can change her mind later, so there is a direct benefit to the male for not harming her.
Now there are animals where a female will be bullied into mating to the point of risking injury or death. Those animals are very rare and have high dimorphism, they have males that are MUCH larger and more dangerous than the females, to the point the female is incapable of being a significant threat to the male. It is most common in animals that express harem polygyny. It also tends to carry the risk of inbreeding.
One horrifying example is hamadryas baboons. Males maintain a harem and threaten any female that even strays too far from the male. They even bite disobedient females.
The following is multiple choice question (with options) to answer.
Animals are unable reproduce if they are dead or cannot find a mate, so it is in their best interest to avoid animals that want to | [
"laugh",
"sing to them",
"murder them",
"kiss them"
] | C | avoiding predators has a positive impact on prey 's ability to reproduce |
OpenBookQA | OpenBookQA-2985 | electromagnetic-radiation, earth, gamma-rays
Title: EM waves with frequency much higher than gamma rays penetrate a planet like Earth? I have just started to study the electromagnetic waves as a personal interest. I wonder if there exist a much higher frequency of electromagnetic wave than Gamma Ray's which can even penetrate Earth. With our current measuring apparatus, is it possible to measure such high frequency waves if they penetrate everything?
Like passing through the earth without any significant energy loss? For an electro-magnetic wave, the ability to penetrate matter goes as $1/{\sqrt{f}}$.
So as you increase the frequency, the penetration gets worse. By the time you get to gamma-rays, the energy is so high that the "rays" (at this point you're better thinking of them as particles - photons) interact with the matter and cause an electromagnetic shower of sub-atomic particles (read up on pair-production and ionisation).
If you want the wave to remain coherent after traversing a large body, you want a very low frequency. Radio waves in the few Hertz range have been used to communicate with submarine deep underwater. The data-rate is very low.
The following is multiple choice question (with options) to answer.
What might have more radiation? | [
"cats",
"grass",
"water",
"cigarettes"
] | D | radiation is when heat is transferred through waves |
OpenBookQA | OpenBookQA-2986 | radiation
You see similar things happening here. The metal rod at the top of the lamp acts as a capacitive ground - given the very high voltage, a tiny charge will flow from the tip of the filament to the rod. There is a small amount of gas in the tube which is ionized and gives rise to the light you see. The electrons eventually bombard the metal "anode" and produce Bremsstrahlung - note that without the metal, you were getting a glow and no reading on the Geiger counter. There is a similar demonstration online which is more convincing in its use of conventional materials, but which otherwise shows many of the same phenomena.
It is almost certainly very inefficient. Most of the energy in an X-ray tube is converted to heat as the electrons burrow too deeply into the tungsten target for their radiation to escape- apart from the fact that only the most violent deceleration produces X-rays with high enough energy to penetrate the bulb and be detected.
I noticed that when the "alpha window" was removed, the reading in your video went up. Since there was also a biscuit tin and glass bulb in the way I suspect there was a lot more low energy radiation generated than was detected. Good stuff for skin cancer.
The experiment as shown should not be repeated. Not only were the HV precautions extremely poor, but so were the radiation safety precautions. Please don't try this at home...
The following is multiple choice question (with options) to answer.
A maglight puts out | [
"a beam",
"fires",
"the sun",
"candles"
] | A | a flashlight emits light |
OpenBookQA | OpenBookQA-2987 | earth, geophysics
Title: What is the most optimal earth's axial tilt in terms of variation of seasons? What is the most optimal earth's axial tilt in terms of variation of seasons?
What would be optimal axial tilt for earth that life would exist and change of seasons would be at minimal level? If Earth had 0 inclination to the ecliptic, then life could still exist and there would be no change in seasons. In fact, at latitudes greater than $-23.5^\circ$ and less than $23.5^\circ$, the seasons are already irregular compared with the rest of the planet; they have two points where the Sun shines directly on top of them, effectively making them have two summers. At the equator, there is practically no/minimal variation in seasons already.
The following is multiple choice question (with options) to answer.
When the Earth is tilted on its axis, as it always is, certain tilts will make it summer one once continent | [
"and birds fly around the moon",
"and beans grow on the other side",
"and another's celebrating Halloween",
"and a desert on another"
] | C | the Earth being tilted on its axis causes ones side of the Earth to receive less energy from the Sun than the other side |
OpenBookQA | OpenBookQA-2988 | # Thread: Most likely of two examples
1. ## Most likely of two examples
Hi My instructor gave us two examples and posed a question:
We have a fair coin which is more likely?
1. We flip the coin 100 times and see exactly 50 heads.
2. We flip the coin 1000 times and see exactly 500 heads.
Someone in the class said immediately that 1 is more likely by a factor of sqrt(10). Why is sqrt(10) the difference? Now explanation was given.
2. ## Re: Most likely of two examples
Hint: Try calculating the actual probability using the PDF (or by using a Normal distribution approximation with continuity correction).
Have you come across using the Normal distribution to approximate a binomial distribution for large values of n?
3. ## Re: Most likely of two examples
The binomial distribution with N= 100, p= 1/2 has mean 50 and standard deviation $\sqrt{(100)(1/2)(1/2)}= \sqrt{25}= 5$. To approximate that with the Normal distribution, use a normal distribution with that mean and standard deviation and find the probability that x is between 50- 1/2= 49.5 and 50+ 1/2= 50.5.
To do the same with N= 1000, p= 1/2, mean is 500 and standard deviation $\sqrt{1000}(1/2)(1/2)}= \sqrt{250}= 5\sqrt{10}$. Find the probability of x between 500- 1/2= 499.5 and 500+ 1/2= 500.5.
The following is multiple choice question (with options) to answer.
Which of the following is most likely to occur? | [
"a felled tree rots",
"a stone pile rots",
"a living tree rots",
"a pile of sand rots"
] | A | dead organisms rot |
OpenBookQA | OpenBookQA-2989 | reproduction, nutrition, ornithology
Title: Do chickens always lay eggs? http://de.wikipedia.org/wiki/Hühnerei says it takes up to 24 h for a chicken to produce an egg.
Is that dependent on the chickens nutrition, i.e., if it does not get enough food or the wrong kind, meaning it can survive on the food but it does not have everything to produce an egg?
Do we have data on this? In short; yes. It depends on the breed (not all lay up to 1 egg/day), the age of the bird and on nutrition. High yielding breeds of chicken are e.g. dependent on supplements of calcium to be able to produce new shells rapidly (e.g. in the form of ground-up shells). Some information on the nutrient requirements of chicken can be found at Feeding the Laying Hen. Egg production will also fluctuate over the year, and will generally decrease e.g. during molting, since energy and nutrients are then diverted to the production of feathers (see info at e.g. The Poultry site).
The following is multiple choice question (with options) to answer.
Which of these lays eggs? | [
"vampire bats",
"flying squirrels",
"lesser whitethroats",
"coyotes"
] | C | birds lay eggs |
OpenBookQA | OpenBookQA-2990 | mechanical-engineering, gears
Hopefully this all makes sense so far.
A lever doesn't actually move strictly up-and-down, though. It rotates about the fulcrum. The actual distance the input traverses is $L_1\theta$, and the output moves $L_2\theta$, where $L_1$ is the length of the lever from the input side to the fulcrum, $L_2$ is the length of the lever from the output side to the fulcrum, and $\theta$ is the angle of how much the lever rotated.
Define the arc length, or distance actually traveled by the input or output end of the lever to be $s$. The input moves:
$$
s_1 = L_1\theta \\
$$
The output moves:
$$
s_2 = L_2\theta \\
$$
If you divide the output by the input, you can see that:
$$
\frac{s_2}{s_1} = \frac{L_2\theta}{L_1\theta} \\
$$
The thetas cancel, and you're left with:
$$
\frac{s_2}{s_1} = \frac{L_2}{L_1} \\
$$
which can be restated as:
$$
\boxed{s_2 = \left(\frac{L_2}{L_1}\right)s_1} \\
$$
The output distance traveled is equal to the input distance times the ratio of lever arm lengths. You can plug this back into the work equation:
$$
F_1 s_1 = F_2 s_2 \\
F_1 s_1 = F_2 \left(\frac{L_2}{L_1}\right)s_1 \\
$$
Cancel the $s_1$:
$$
F_1 = \left(\frac{L_2}{L_1}\right)F_2 \\
\boxed{F_2 = \left(\frac{L_1}{L_2}\right)F_1} \\
$$
The following is multiple choice question (with options) to answer.
You would use a lever to move a | [
"feather",
"grain of sand",
"drop of water",
"safe"
] | D | a lever is used for moving heavy objects |
OpenBookQA | OpenBookQA-2991 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
In America, we know that January is a Winter month. But in other parts of the world, its another season. due to | [
"store",
"coma",
"differing hemisphere",
"different world"
] | C | January is during the winter in the northern hemisphere |
OpenBookQA | OpenBookQA-2992 | thermal-radiation
As my target is always the same with fixed emissivity, there should be no vital need for 2-band measurement.
Are there any issues with this single-band temperature measurement approach? Alternatively, I might add $\mathrm{PbS}$ photoresistor ($2.1\,\mu\text{m}$ maximum), but they are not that precise, quite expensive and scarce. What are your thoughts or suggestions? I am using a CN7600 in my furnace. Omega 76000 This controller is very accurate. As for all them measurements I have made it keeps the oven 750 C. It fluctuates from 750 to 751 which just over 1% if I take 750.5 as my required temperature. Now whit a little improvement in the furnace design I can improve this. The problem is eliminating "Hot pockets" in the furnace by having a very mild air/gas flow around the subject. The prove wires can be in a Pirex tube for temps under 1000 C and the controller can compensate for this.
The following is multiple choice question (with options) to answer.
Thermistors measure | [
"depth",
"heat",
"height",
"pressure"
] | B | a thermometer is used to measure temperature |
OpenBookQA | OpenBookQA-2993 | orbit, gravity, astrophysics
Trying to look at this in another way, consider the angular momentum of the spacecraft. As long as it is only under sun's gravitational influence, its angular momentum cannot change. However, once it's under the influence of another planet, the two angular momenta - one w.r.t. the sun and one w.r.t. the planet (due to their relative motion) - add, and once out of the gravitational influence of the planet, their relative components can be adjusted (based on the angle of approach towards the planet and the angle at which it flies away after the slingshot) in order to increase the angular momentum w.r.t. the sun, which in turn puts it in a larger orbit, allowing it to travel farther away than before.
The following is multiple choice question (with options) to answer.
The way that the planet spins and moves through space can effect how | [
"how the moon phases",
"the plants we are able to eat",
"the stars location appearance in relation to earth",
"the heat of the sun"
] | C | stars appear to move relative to the horizon during the night |
OpenBookQA | OpenBookQA-2994 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
On continents nearer the north pole than the south, winter months such as November see | [
"the most daylight",
"the longest daylight",
"growing daylight hours",
"short daylight"
] | D | the amount of daylight is least in the winter |
OpenBookQA | OpenBookQA-2995 | waves, atmospheric-science, turbulence
The clouds form if the rising air reaches the lifted condensation level before the updrafts are stopped by an inversion or stable layer. The air is (relatively) clear above the downdrafts. If the convection rolls were perfectly circular, the cloud row spacing would be twice the height of the inversion/stable layer.
Mathematically, there are many wavelength solutions to convection, but the wavelength that dominates is the fastest growing one. In the Boussinesq approximation, which is reasonably valid here, this turns out to have a wavelength of $2\sqrt{2}\sim 3$ times the height of the convecting layer, i.e. slightly flattened. (See, for example, Eq. 21 of Kuettner (1971) "Cloud bands in the earth's atmosphere: Observations and Theory".)
For typical cumulus cloud heights of $\sim 2$ km, we expect typical spacings of about $6$ km.
Wave, lee, or mountain clouds are lines of clouds downwind of an obstacle (such as a mountain range). The lines are parallel to the wind direction. These are buoyancy waves where wind pushes denser air over an obstacle (e.g. a mountain range) and it ends up above less dense air on the other side. This dense air starts to fall but it overshoots into even higher density air at lower altitude, which forces it back up, and the air ends up bouncing up and down until the oscillations die out. If the vertical temperature profile of the air then is known, it is possible to estimate the vertical buoyancy angular frequency
$$N=\sqrt{\frac{g}{\theta}\frac{d\theta}{dz}}$$
The following is multiple choice question (with options) to answer.
How can H2O on the ground eventually rise into the sky? | [
"freezing",
"raining",
"snowing",
"evaporation"
] | D | evaporation is when water is drawn back up into the air in the water cycle |
OpenBookQA | OpenBookQA-2996 | newtonian-mechanics, energy, everyday-life, biophysics
Running involves more and varied movements, it's a very different gait. It is definitely not just the same movement as walking but faster. Some of those movements are vertical, or relate to jumping, some have shock absorption components and relate to landing. Much of that extra energy is dissipated both ways - we use energy both to jump and to cushion and come to a halt on landing. We also accelerate our feet to match our ground speed and must slow them to zero each stride, then speed and lift the other way as well, not just rely on gravity and pendulum activity. The fact this is at extension and not at ground impact doesn't change anything. Again, energy is lost both ways. I'm also going to guess that it's harder to be efficient across a wider compared to narrower range of motions, therefore the wider range of movements and systems used in running means it's much more likely that efficiency varies considerably, according to biological subsystem or type of movement.
Human gross muscle motion energy handling/metabolism is not efficient and doesn't behave like an ideal object. We have multiple energy pathways, and switch between them according to need. This happens less with walking, more with vigorous exercise like running. The "emergency" or "sustained activity" energy cycle our bodies switch to, when running, is less efficient - if it was more efficient it would probably have evolved as our primary not our fallback. And of course many biochemical reactions and body responses just aren't linear; they also may have min/max rates or durations.
The following is multiple choice question (with options) to answer.
Webbed feet are used to move faster through what? | [
"rain",
"winds",
"clouds",
"swamps"
] | D | webbed feet are used for moving faster through water by aquatic animals |
OpenBookQA | OpenBookQA-2997 | paleontology, fossils, desert
Title: Why are many fossils found in deserts? Why are deserts famous for fossils? Is it a coincidence? Some examples:
Giant Catfish Fossil Found in Egyptian Desert
Chile's stunning fossil whale graveyard explained
Giant Dinosaur Fossil Found in Sahara Desert I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.
Do not forget about plate tectonics and climate change. One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location. Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils. At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.
Later, that plate move and ended up inland, in what is not North America. Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters. Desert regions tend to be subjected to this type of erosion and exposure making such finds easier. If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.
The following is multiple choice question (with options) to answer.
A camel can survive in the desert because of | [
"horses",
"hoarded energy",
"sandy nostrils",
"star gates"
] | B | An example of an adaptation is camel humps |
OpenBookQA | OpenBookQA-2998 | general-biology, habitat
Title: How does life change when you dig deeper? I've just realized that I have no idea what life / biotopes / soil looks like when you dig deeper than a few meters.
I know that in the first meter of soil you can find all sorts of live animals (like moles and rabbits), insects (like ants, but many more), plants, and single-celled organisms, of course.
But how does that change when you get to the depth of a metro station (below 30m)? When you plan to build a metro, do you have to consider that you might destroy a biotope?
I guess there is a point from which you will quite certainly not find animal/plant life in the soil anymore. This will, of course, depend on where exactly you are. But can you give a rough estimate of how deep we're talking? 50m? 100m? 1km? Extremophile bacteria and archea are living very deep beyond our imaginations. This is what you need for general composition at different depths. And this and this is for the deepest living organism known ! Following is image from (Manson et al 2010) which shows at what depth you will get bacteria
Even more deeper, Wold's single species ecosystem, Desulforudis audaxviator which can be found 3 km below sea level.
The following is multiple choice question (with options) to answer.
Which would likely render a habitat dead? | [
"planting new trees",
"a light drizzle",
"a human camping",
"an apartment complex"
] | D | if a habitat is destroyed then that habitat can not support animals |
OpenBookQA | OpenBookQA-2999 | earth-history, mass-extinction, geobiology, evolution, ecology
Title: Why haven't weeds overtaken the entire planet? Given how rapidly weed plants spread and grow, choking out all other plant life, how come after millions of years we haven't ended with forests full of thistle or pokeweed, as opposed to pines or oak trees? A weed is just a plant where you do not want it. Totally a matter of context. Tumbleweeds are non-native, introduced centuries ago. I assume you mean the invasive species of plants that have been spread by humans and are disrupting ecologies throughout most of the world
Until recently, these plants we consider weeds were limited in their range to home environments simply by geographic barriers and surrounding unfriendly environments. And the natural consumers, parasites and competitors in the home environments had adjusted to these plants and kept them in check.
When non-native plants are introduced into a new environment by humans, most of them do not thrive, but occasionally a plant is wildly successful. Eventually the potential consumers, parasites and competitors in that new environment will adjust through evolution. But the tragedy is that many or most of the original species will be destroyed before that balance is restored in a new, way more simplified form. The landscape itself may be totally changed. Removal of a key original species can cause great change too: How Wolves Change Rivers.
Not only will many ecologies be reduced to much simpler versions, even if they eventually conquer the invasive plant, those simplified ecologies will closely resemble each other, if their geography is similar, even if on the other side of the world. If humans were to totally stop transplanting invasive species (collapse of civilization?), diversity would return after millions of years. We know this from Extinction Events.
So to answer you question, weeds before human intervention generally did not take over in their home environments because the potential weeds and their natural consumers, parasites and competitors all evolved together in a quasi-equilibrium. Now, however, most ecologies throughout the world are out of equilibrium because of environmental change and/or invasive species. This will inevitably lead to simplified, usually less robust, weedy ecologies throughout the world. That reduction in diversity might as well be considered a permanent situation compared to the timescale of civilization.
The following is multiple choice question (with options) to answer.
Seeds from a prickle bush can be moved across a continent if | [
"foxes nap",
"sharks swim",
"birds die",
"gulls help"
] | D | birds are a vehicle for spreading the seeds of a plant |
OpenBookQA | OpenBookQA-3000 | Note:
Depending on where, and how frequently, you round during this function, your answers may be off a few cents in either direction. Try rounding as few times as possible in order to increase the accuracy of your result.
The following is multiple choice question (with options) to answer.
Which of the following is more accurate? | [
"ice has greater mass when carved",
"ice has greater mass when crushed",
"ice disappears instantly when carved",
"ice has approximately equivalent mass when carved"
] | D | as state of matter changes , mass will not change |
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