Specialty Digest

DISCOVER IDEAS THAT SHAPE OUR WORLD

Specialty Knowledge

Science & Mathematics

Physics, chemistry, biology, space and mathematics

Mitochondrial DNA

In simple terms Almost all of a person’s DNA sits in the nucleus of each cell. A small amount sits somewhere else, inside the mitochondria. Mitochondria are the structures that convert energy from food into a form cells can use. They carry a little DNA of their own, called mitochondrial DNA, or mtDNA. How it […]

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Mitochondrial DNA is a small, separate loop of DNA inside a cell's mitochondria, inherited almost entirely from the mother.

Mole (chemistry)

In simple terms A mole is a counting unit for very small things. One mole is a fixed number of particles, the way a dozen is a fixed number of eggs. The number is enormous because atoms are tiny. NIST calls the mole a shorthand way to talk about huge numbers, especially of tiny things.

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A mole is the SI unit of amount of substance: exactly 6.02214076 times 10 to the power 23 entities, such as atoms, molecules or ions.

Moment magnitude scale

In simple terms The moment magnitude scale is the standard way seismologists state how big an earthquake was. It is written Mw, and it has replaced the Richter scale for most serious work. It describes the earthquake at its source. One earthquake has one magnitude, wherever you happened to be standing. How it works The

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The moment magnitude scale, written Mw, states an earthquake's size from the slip, fault area and rock rigidity at its source.

Nonresponse bias

In simple terms Every survey misses people. Nonresponse bias is what happens when the people it misses differ from the people it reaches. If the difference has nothing to do with the question being asked, the estimate can still be sound. If it does, the number is wrong, and a larger sample will not rescue

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Nonresponse bias is the error that appears when the people who answer a survey differ from those who do not in ways that matter.

Orbital eccentricity

In simple terms Orbital eccentricity is a single number that says how far an orbit departs from a perfect circle. It is written as e. A value of 0 is a circle, and the larger the number, the more stretched the path. How it works NASA’s Jet Propulsion Laboratory defines eccentricity as the ratio of

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Orbital eccentricity is a number describing how stretched an orbit is, from 0 for a circle to above 1 for a path that never returns.

Percentage point

In simple terms A percentage point is the unit for the gap between two percentages. You find it by simple subtraction: a rate that moves from 10% to 12% has risen by 2 percentage points. The term exists to prevent a common mix-up. That same move from 10% to 12% is also a 20% increase,

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A percentage point is the simple difference between two percentages: a rate rising from 10% to 12% has risen by 2 percentage points.

pH

In simple terms pH tells you how acidic or basic a water based liquid is. Lemon juice is acidic, a baking soda solution is basic, and pure water sits between them. The scale runs from 0 to 14. Seven is neutral, below 7 is acidic, and above 7 is basic, also called alkaline. How it

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pH measures how acidic or basic a water based solution is, on a scale where 7 is neutral, lower is acidic and higher is basic.

Plate tectonics

In simple terms Plate tectonics is the idea that Earth’s rigid outer shell is broken into large slabs that move slowly over the hotter, softer layer underneath. The US Geological Survey describes a dozen or more large and small solid slabs, called lithospheric or tectonic plates, moving relative to one another on top of a

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Plate tectonics is the theory that Earth's outer shell is broken into slabs that move, building mountains and causing earthquakes at their edges.

Prime number

In simple terms A prime number is a whole number greater than 1 that can be divided evenly only by 1 and by itself. Seven is prime, because no other whole number divides it without a remainder. Six is not, because 6 = 2 × 3. Whole numbers above 1 that are not prime are

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A prime number is a whole number greater than 1 whose only positive divisors are 1 and itself, such as 2, 3, 5 and 7.

Replication crisis

In simple terms A finding replicates when a different team asks the same question, gathers its own data, and reaches a consistent answer. The replication crisis is the concern that this happens less often than scientists assumed. It is an argument about how much confidence a single published result deserves. It is not a claim

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The replication crisis is the finding that many published scientific results do not hold up when other researchers repeat the study with new data.