Screening-Off and the Units of Selection

1992 ◽  
Vol 59 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Elliott Sober
Keyword(s):  
Units Of Selection ◽  
Screening Off

Lead Screening Off Radar for Urban Youths

2006 ◽  
Vol 36 (18) ◽  
pp. 59
Author(s):  
ERIK GOLDMAN
Keyword(s):  
Screening Off

O pewnym założeniu twierdzenia Bella

2018 ◽  
Vol 52 (4) ◽  
pp. 39
Author(s):  
Jan Czerniawski
Keyword(s):  
Screening Off ◽  
Parameter Independence

Dowód twierdzenia Bella sprowadza się do wyprowadzenia którejś z nierówności Bella. W ich standardowych wyprowadzeniach jednak kluczową rolę odgrywa warunek faktoryzowalności łącznego prawdopodobieństwa warunkowego, który można uzyskać jako konsekwencję dwóch innych warunków, znanych jako parameter independence i outcome independence. Pierwszy z nich jest dość oczywistym wyrazem warunku lokalności, natomiast drugi budzi wątpliwości. Ponieważ jednak jest on uszczegółowieniem warunku screening off zasady wspólnej przyczyny, jego podważenie wymagałoby zakwestionowania również tego warunku. Gdyby się to powiodło, efektywny dowód twierdzenia Bella wymagałby wyprowadzenia nierówności Bella nie wykorzystującego żadnego uszczegółowienia warunku screening off. Przestawiona zostanie sugestia kierunku, w jakim powinny iść poszukiwania modelu naruszającego ten warunek.

Mother Culture, Meet Mother Nature

2018 ◽  
Author(s):  
Luc Faucher ◽  
Pierre Poirier
Keyword(s):  
Evolutionary Algorithms ◽  
Cultural Change ◽  
Evolutionary Information ◽  
Multiple Forms ◽  
Human Immune System ◽  
Units Of Selection ◽  
Pluralistic Approach ◽  
Human Immune ◽  
Plausible Theory ◽  
Different Time Scales

Research on the adaptive characteristics of the human immune system reveals that evolutionary algorithms are not strictly matters of replication. And research in genomics suggests that there is no a single source of evolutionary information that carries the same content in every environment. A plausible theory of cultural evolution must acknowledge the possibility that multiple selective algorithms are operating at different time-scales, on different units of selection, with different logical structures; but it must explain how different selective processes are interfaced to yield culturally stable phenomena. This paper advances an empirically plausible approach to memetics that recognizes a wider variety of evolutionary algorithms; and it advances a pluralistic approach to cultural change. Finally, it shows that multiple forms of processing, operating at different timescales, on different units of selection, collectively sustain the human capacity to form and use certain types of representations.

A Structural Approach to Defining Units of Selection

1989 ◽  
Vol 56 (3) ◽  
pp. 395-418 ◽  
Author(s):  
Elisabeth A. Lloyd
Keyword(s):  
Structural Approach ◽  
Units Of Selection

scholarly journals A New Condition for Transitivity of Probabilistic Support

Erkenntnis ◽  
2021 ◽  
Author(s):  
David Atkinson ◽  
Jeanne Peijnenburg
Keyword(s):  
Interesting Property ◽  
Sufficient Condition ◽  
Probabilistic Support ◽  
Screening Off

AbstractAs is well known, implication is transitive but probabilistic support is not. Eells and Sober, followed by Shogenji, showed that screening off is a sufficient constraint for the transitivity of probabilistic support. Moreover, this screening off condition can be weakened without sacrificing transitivity, as was demonstrated by Suppes and later by Roche. In this paper we introduce an even weaker sufficient condition for the transitivity of probabilistic support, in fact one that can be made as weak as one wishes. We explain that this condition has an interesting property: it shows that transitivity is retained even though the Simpson paradox reigns. We further show that by adding a certain restriction the condition can be turned into one that is both sufficient and necessary for transitivity.

scholarly journals Screening off generalized: Reichenbach’s legacy

Synthese ◽  
2021 ◽  
Author(s):  
David Atkinson ◽  
Jeanne Peijnenburg
Keyword(s):  
Sufficient Condition ◽  
Probabilistic Causality ◽  
Hans Reichenbach ◽  
Queen Victoria ◽  
Interesting Difference ◽  
Probabilistic Support ◽  
Screening Off

AbstractEells and Sober proved in 1983 that screening off is a sufficient condition for the transitivity of probabilistic causality, and in 2003 Shogenji noted that the same goes for probabilistic support. We start this paper by conjecturing that Hans Reichenbach may have been aware of this fact. Then we consider the work of Suppes and Roche, who demonstrated in 1986 and 2012 respectively that screening off can be generalized, while still being sufficient for transitivity. We point out an interesting difference between Reichenbach’s screening off and the generalized version, which we illustrate with an example about haemophilia among the descendants of Queen Victoria. Finally, we embark on a further generalization: we develop a still weaker condition, one that can be made as weak as one wishes.

Interactions of polynucleotides and their components

1968 ◽  
Vol 23 (1) ◽  
pp. 25-30 ◽  
Author(s):  
J. Clauwaert ◽  
J. Stockx
Keyword(s):  
Ionic Strength ◽  
Inductive Effect ◽  
Large Range ◽  
Electrostatic Attraction ◽  
Screening Off ◽  
Electron Withdrawal ◽  
New Treatment ◽  
Ribose Moiety ◽  
Phosphate Groups ◽  
Electron Attraction

The pK' values of the current bases, nucleosides, nucleotides, nucleotide derivatives and poly U have been determined over a large range of ionic strength. The pK' shifts of the monomers due to variations in ionic strength can be accounted for qualitatively and quantitatively by means of the relationThe collision diameters of uracil, uridine, uridine cyclic -2':3'-phosphate and 3' (2') -uridylic acid were determined. The introduction of phosphate affects the charge, resulting into differences in activity coefficient between nucleotides and their corresponding nucleosides and bases. A substitution of -H by ribose at N(3) of uracil or cytosine or at N(9) of adenine or guanine results into an electron withdrawal from the bases with lowering of the pK' value. 2'-Deoxyribose exhibits a weaker electron attraction. Introducing -CH3 at C(5) of uracil yields electrons to the base and the pK values of various thymine derivatives are about 0.5 pH units higher than those of the corresponding uracil derivatives. A phosphate group on C2 or C3 results in an electrostatic attraction of the dissociable proton, so that the pK' is increased at low ionic strengths; at higher ionic strengths screening off occurs and the pK' values of the nucleotides become almost the same as those of the corresponding nucleosides. The site of substitution on the ribose moiety is important: C2'-O-phosphate seems to exert a stronger electrostatic attraction on - NH3⊕ groups than C3'-O-phosphate, whereas C5'-O-phosphate exerts in addition an inductive effect that is dependent on the presence of - OH on C2. The electrostatic influence of the phosphate groups on the uracil moiety in UpU, UpC and CpUpC runs roughly parallel to that found in cyclic-2':3'-nucleotides. The pK' shifts experienced in poly U are related to the polyelectrolyte character of this polymer. A new treatment for the evaluation of the electrostatic potential of polynucleotides (poly U) is proposed that is based on the usual rodlike (polyelectrolyte) model.

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