positive and negative
21Negative campaigning — Part of the Politics series Political campaigning Finance …
22Positive feedback — Alarm or panic can spread by positive feedback among a herd of animals to cause a stampede. Positive feedback is energy taken from the output of a system and reapplied to the input, which is phase congruent with the input signal. A system… …
23Negative liberty — Part of a series on Freedom Concepts …
24Negative and positive atheism — A diagram showing the relationship between the definitions of weak/strong and implicit/explicit atheism. Explicit strong/positive atheists (in purple on the right) assert that at least one deity exists is a false statement. Explicit weak/negative …
25Negative predictive value — In statistics and diagnostic testing, the negative predictive value (NPV) is a summary statistic used to describe the performance of a diagnostic testing procedure. It is defined as the proportion of subjects with a negative test result who are… …
26Negative index metamaterials — A negative index metamaterial causes light to refract, or bend, differently than in more common positive refractive index materials. Negative index metamaterials or negative index materials (NIM) are artificial structures where the refractive… …
27Negative frequency — The concept of negative and positive frequency can be as simple as a wheel rotating one way or the other way.[citation needed] A signed value of frequency indicates both the rate and direction of rotation.[citation needed] The rate is expressed… …
28Negative temperature — In physics, certain systems can achieve negative temperatures; that is, their thermodynamic temperature can be a negative quantity. Negative temperatures can be expressed as negative numbers on the kelvin scale. Temperatures that are expressed as …
29Negative base — Numeral systems by culture Hindu Arabic numerals Western Arabic Eastern Arabic Indian family Tamil Burmese Khmer Lao Mongolian Thai East Asian numerals Chinese Japanese Suzhou Korean Vietnamese …
30Negative feedback — Most endocrine hormones are controlled by a physiologic negative feedback inhibition loop, such as the glucocorticoids secreted by the adrenal cortex. The hypothalamus secretes corticotropin releasing hormone (CRH), which directs the anterior… …
