- rule
- A
*criterion*,*standard*, or*guide*governing a*procedure*, arrangement,*action*, etc. SEE ALSO: law,*principle*,*theorem*. [O. Fr. reule, fr. L. regula, a*guide*,*pattern*]-the tendency of the sum of the*Abegg*r.*maximum**positive*and*maximum**negative**valence*of a particular*element*to equal 8; e.g., C may have a*valence*of +4 and −4, O of +6 and −2. Sometimes loosely stated as all atoms have the same*number*of valences, a consequence of the tendency of*valence**electron*shells to be filled to 8.-**American Law Institute r.**a*test*of criminal responsibility (1962): “a person is not responsible for criminal conduct if at the*time*of such conduct as a result of*mental**disease*or*defect*he or she lacks substantial*capacity*either to appreciate the wrongfulness of the conduct or to conform the conduct to the requirements of law.”-**r. of**r. that a*bigeminy**ventricular**premature**beat*will follow the*beat*terminating a long*cycle*. Sudden prolongation of the*ventricular**cycle*, by changing the refractoriness in the*conduction**system*, causes a*peripheral**region*of bidirectional*block*to become transiently unidirectional and*thus*opens*potential*pathways for*reentry*to occur.-in DNA the*Chargaff*r.*number*of*adenine*units equals the*number*of*thymine*units; likewise, the*number*of*guanine*units equals the*number*of*cytosine*units.-an obsolete r. for an*Clark**weight*r.*approximate*child's*dose*, obtained by dividing the child's*weight*in pounds by 150 and multiplying the result by the*adult**dose*.-**Cowling r.**an obsolete r. for a child's*dose*: that*fraction*of the*adult**dose*obtained by dividing the age of the child at the nearest birthday by 24.-an American*Durham*r.*test*of criminal responsibility (1954) under which an accused person is not held criminally responsible if the unlawful act was the*product*of*mental**disease*or*mental**defect*.-**Goriaew r.**rarely used*term*for a r. of a*blood count*ing*field*by which it is marked off in a*series*of squares, some of which are again subdivided into 16 smaller ones.-**Haase r.**the*length*of the*fetus*in centimeters, divided by 5, is the*duration*of*pregnancy*in months, i.e., the age of the*fetus*.-**Hückel r.**the*number*of depolarized electrons in an*aromatic**ring*is equal to 4n + 2 where*n*is 0 or any*positive*integer; l-tyrosine, l-phenylalanine, l-tryptophan, and l-histidine (when the*imidazole**ring*is deprotonated) obey this r..-a*Ingelfinger*r.*principle*developed by Franz*Ingelfinger*for use in the editorial offices of the New England Journal of Medicine, stating that original articles submitted for publication will be reviewed on the understanding that the same information will not be submitted for publication elsewhere during the*period*of*review*; has been adopted by many other peer-reviewed*medical*journals.-the classical, outmoded statement that naturally occurring terpenes are built up by*isoprene*r.*condensation*of*isoprene*units by either a 1-4*linkage*(“head to tail”) or a 4-4*linkage*(“tail to tail”).-after an*Jackson*r.*epileptic**attack*,*simple*and quasiautomatic functions are less affected and more rapidly recovered than the more*complex*ones.-**Le Bel-**the*van't Hoff*r.*number*of stereoisomers of an*organic**compound*is 2^{n}, where*n*represents the*number*of*asymmetric**carbon*atoms (unless there is an*internal**plane*of symmetry); a corollary of their simultaneously announced conclusions, in 1874, that the most probable*orientation*of the bonds of a*carbon**atom**linked*to four groups or atoms is toward the apexes of a tetrahedron, and that this accounted for all then-known phenomena of*molecular**asymmetry*(which involved a*carbon**atom**bearing*four different atoms or groups). SEE ALSO:*stereoisomerism*.-in*Liebermeister*r.*adult**febrile**tachycardia*, about eight*pulse*beats correspond to an*increase*of 1°C.-**Meyer-**because*Overton*r.*inhalation*agents act via the lipid-rich CNS cells,*anesthetic**potency*increases with*lipid**solubility*.-the classic English*M'Naghten*r.*test*of criminal responsibility (1843): “to establish a*defense*on the ground of*insanity*, it*must*be clearly proved that, at the*time*of committing the act, the party accused was laboring under such a*defect*of reasoning, from*disease*of the*mind*, as not to know the nature and quality of the act he was doing, or if he did know it, that he did not know he was doing what was wrong.”-*Nägele*r.*determination*of the estimated*delivery*date by adding 7 days to the first day of the last*normal**menstrual**period*, counting*back*3 months, and adding 1*year*.-**New Hampshire r.**pioneering American*test*of criminal responsibility (1871): “if the [criminal] act was the offspring of*insanity*, a criminal intent did not produce it.”-**r. of nines***method*used in calculating*body**surface**area*involved in burns whereby values of 9% or 18% of*surface**area*are assigned to*specific*regions as follows:*Head*and*neck*, 9%;*anterior**thorax*, 18%;*posterior**thorax*, 18%; arms, 9% each; legs, 18% each; and*perineum*, 1%.-**Ogino-Knaus r.**the*time*in the*menstrual**period*when*conception*is most likely to occur is at about midway between two*menstrual*periods;*fertilization*of the*ovum*is least likely just before or just after*menstruation*; the*basis*for the*rhythm**method*of*contraception*.-**r. of**an*outlet**obstetric*r. for determining whether the*pelvic**outlet*will permit the*passage*of a*fetus*; the sum of the*posterior**sagittal**diameter*and the*transverse**diameter*of the*outlet**must*equal at least 15 cm if a normal-sized*baby*is to pass.-an*phase*r.*expression*of the relationships existing between systems in*equilibrium*:*P*+*V*= C + 2, where*P*is the*number*of phases,*V*the*variance*or degrees of freedom, and C the*number*of components; it also follows that the*variance*is*V*= C + 2 −*P*. For H_{2}O at its triple*point*,*V*= 1 + 2 − 3 = 0, i.e., both*temperature*and*pressure*are fixed. SYN: Gibb*phase*r..-each*Prentice*r.*centimeter*of*decentration*of a*lens*results in 1*prism**diopter*of*deviation*of*light*for each*diopter*of*lens**power*.-the*Rolleston*r.*ideal**adult**systolic**blood**pressure*is 100 plus half the age, whereas the maximal*physiologic**pressure*is 100 plus the age; of historical interest.-the*Schütz*r.*rate*of an*enzyme**reaction*is proportional to the square*root*of the*enzyme**concentration*; applied specifically to*pepsin*within a limited*range*. SYN:*Schütz*law.-**stopping rules**in randomized controlled trials and other*systematic*experiments on human subjects, rules laid down in*advance*that specify conditions under which the*experiment*will be terminated, e.g., unequivocal demonstration that one*regimen*in a randomized controlled*trial*is clearly*superior*to the other, or that one is clearly harmful.-**Trusler r. for**a*pulmonary**artery**banding**method*that gives*guidance*as to the correct tightness of the*band*; the*degree*of*banding*for a*complex**congenital**cardiac**anomaly*with bidirectional shunting less than that for*simple*ones.-an obsolete r. to determine a child's*Young*r.*dose*: 12 is added to the child's age and the sum is divided by the age; the*adult**dose*divided by the*figure*so obtained gives the proper*dose*.* * *

(rl) [L.*regula*] a statement of conditions commonly observed in a given situation, or a statement of a prescribed course of action to obtain a result. Cf.*law.*

*Medical dictionary.
2011.*