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What is the principle of the IMViC test?

The indole test is performed on a SIM medium or in tryptophan broth and a positive or negative result is obtained after adding Kovac's reagent. Methyl red and Voges-Proskauer tests are both done in a MR-VP broth. A positive or negative result is obtained after adding a methyl red reagent for the methyl red test, or after adding Barritt's A and Barritt's B reagents for the Voges-Proskauer test. Citrate utilization is performed on Simmon's citrate agar and tests positive or negative by bacterial growth and color.\nThe enterobacteria can be identified by the combination of pos..

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What is an example of a eukaryotic organism?

Plants, fungi and animals are all examples of eukaryotic organisms, whereas bacteria and viruses are considered prokaryotes. The eukaryote cell is in excess of 1,000 times the mass of a prokaryote. Furthermore, they are capable of many more metabolic processes due to them having specialized structures called organelles. The main difference is the presence of the nucleus, and it is this feature that eukaryotes derive their name from, as the word means "true nucleus."

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How do you test a structure for Von Mises stress?

Determine the yield strengthFind the yield strength of the structure's material by locating the point on a stress-strain diagram where plastic deformation begins. The value of the yield strength for many materials is available online.Find the principal stressesFind the normal stresses acting on the structure along the x, y and z-axes, and use these values to determine the principal stresses. These principal stresses are labelled sigma-1, sigma-2 and sigma-3.Calculate the Von Mises stressUse the values of the principal stresses to find the Von Mises stress. The expression for this is:\nsig..

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How loud is 75 decibels?

A decibel is a unit of sound level measurement. Decibels are measured on a logarithmic scale of loudness because human ears detect changes in volume in a non-linear fashion. A difference of 1 decibel is the minimum change in volume. Three decibels difference is a moderate change in volume. A change of 10 decibels is perceived by the listener to be a doubling of volume. Decibels are abbreviated as dB.\nThe threshold of hearing is zero decibels. A whisper is about 15 to 25 decibels. Background noise is generally about 35 decibels. The level at which sustained exposure might result in hearing los..

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What is the lacZ gene?

LacZ is a part of the gene family called the lac operon. The lac operon is a system of three genes along with a promoter, terminator, operator and regulator. The three genes present in the lac operon are lacZ, lacY and lacA. The other two genes in the lac operon, lacY and lacA, are also used in the breakdown of lactose but do not have the same function as lacZ. Only the lacZ product, beta-galactosidase, can break the bond between galactose and glucose in lactose molecules.\nLacZ is an important gene in the study of E.coli because it is used as a reporter gene in bacteria that do not normally e..

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What is the theme of Philip Larkin's poem "Toads"?

During his lifetime, Larkin published just five small volumes of poetry. In spite of this, he was considered one of the greatest poets in postwar Britain, and was offered the position of Poet Laureate in 1984, which he promptly declined. He preferred a more private and humble life.\n\n"Toads" describes two toads, one representing a life visible to the external world, meeting the needs of those around it. This is a representation of people who must work for wages to earn a living, whether or not they enjoy what they are doing. The second toad is a form of the first, seen only by viewing work as..

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What year did we land on the moon?

Armstrong was accompanied by fellow Americans Buzz Aldrin and Michael Collins. The mission to land on the moon was code named Apollo 11. A Saturn V rocket powered the voyage and took off from the Kennedy Space Center in Florida. The lunar landing module, named Eagle, touched down on the moon, in the Sea of Tranquility. Over half a billion people around the world watched these first steps on their televisions.

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What are a few gold mines in the United States?

Gold was originally discovered in North America in 1782 in Virginia, but it was not until 1799 when it was first mined. The first gold mining operation was established on Reed Farm in North Carolina. Most people, however, commonly associate the discovery of gold in the United States with the California Gold Rush, which began in the late 1840s.\nSince that time, gold production has occurred primarily in the mountainous regions of the west. Once gold-rich states such as North Carolina and Georgia have almost entirely depleted their gold reserves, and they do not even appear on the U.S. Geologica..

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Which animals eat caterpillars?

In the food chain, caterpillars are mostly herbivores and are known to eat many different types of plant leaves. However, there are some carnivorous species that eat or prey upon other insects. Similarly, some caterpillars are considered a threat to agricultural crops. There are approximately 20,000 species of caterpillars that are found all over the world.Caterpillars are in this larval stage for about 3 weeks. Caterpillars come in various colors like orange, brown and red. They can range in size from 30 to 60 millimeters.

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What is the velocity ratio?

Velocity ratio is also defined as the ratio of a distance through which any part of a machine moves, to that which the driving part moves during the same time. An object has a mechanical advantage if it exerts a force higher than the velocity ratio. This happens because the object’s force is enough to trade off the force against it. When driving a car, for example, the force of gravity and friction are against the car’s motion.

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