Identical Rules Research Articles

Topographical analysis of spatial patterns generated by a cellular automaton model of the proliferation of a cancer cell line in vitro.

A well‐suited model to simulate cellular population dynamics is the two‐dimensional cellular automaton model, which consists of a lattice of sites, the value ai,j of each site being updated in discrete time steps according to an identical deterministic rule depending on a neighbourhood of sites around it. A cellular automaton is described which mimics cell population proliferation by replacing the site values by the age and the cycle phase of cells. The model takes into account the size of the cells. It is used to simulate the proliferation of the human breast cancer cell line MCF‐7 and the results of the simulation are compared with experimental data obtained from a light microscopic image analysis of the proliferation process. The initial configuration of the cellular automaton is obtained from the discretization of the results of the initial stage of the image processing. After each day of proliferation the pattern obtained from the simulation is compared to the experimental result of the corresponding image analysis. The comparison is made from a topographical point of view through the concept of the minimal spanning tree graph. The agreement between experiment and model is a good starting point to complex models such as cell proliferation under growth effectors or drugs.

`Ought' and Extensionality

In deontic logic it is widely assumed that 'ought'-contexts are nonextensional, just as contexts formed by necessity and belief operators are. Yet questions of quantification, referential transparency and opacity, extensionality, etc. are rarely examined closely in deontic logic. Perhaps that is because deontic logicians have concentrated on problems that arise at the level of propositional logic, and because it is easy to assume that the extension of propositional deontic logic to first-order systems will follow the pattern already established in other areas of modal logic. I will argue here, however, that such an extension is not as smooth as one might expect. In particular, I will argue that, contrary to expectation, there is good reason to consider deontic operators, unlike alethic and intentional modalities, to be fully extensional or referentially transparent with respect to singular terms. Yet if the deontic modalities are extensional, there is a serious risk that deontic logic collapses to triviality. To escape this dilemma, I propose a modification of the standard way of interpreting first-order deontic statements whereby 'ought'-statements are fully extensional for all singular terms and classical rules for quantification and identity apply to them without restriction, while the modalities retain their deontic character. The issue of extensionality arises when deontic operators are included in a first-order language including identity and definite descriptions, for which I will use the usual notation. Here it will be sufficient to focus on the single operator 0 which may apply to any sentence of the language. This is the deontic operator expressed in English by 'it ought to be that . . .' or 'it is obligatory that. . . 9. Since all of the cases I will be examining apply this operator to sentences that say a person performs some action or does something, it is appropriate to paraphrase locutions 'it ought to be that s does A' or 'it is obligatory that s A's' by 's ought to do A' or 's is obliged to A'. If one

Entity identification in database integration

The objective of entity identification is to determine the correspondence between objective instances from more than one database. This paper examines the problem at the instance level assuming that schema level heterogeneity has been resolved a priori. Soundness and completeness are defined as the desired properties of any entity-identification technique. To achieve soundness, a set of identity and distinctness rules have to be established for the entities in the integrated world. We then propose the use of extended key, which is the union of keys (and possibly other attributes) from the relations to be matched, and its corresponding identity rule to determine the equivalence between tuples from relations that may not share any common key. Instance level functional dependencies (ILFD), a form of semantic constraint information about the real-world entities, are used to derive the missing extended key attribute values of a tuple. Formal properties of ILFDs are derived. Results from a Prolog-based prototype entity-identification system are presented.

A Representation of SFP

A sequent structure of Gentzen style entailment with identity, weakening, and cut rules is given and shown to be basic to information systems. A category of strongly finite sequent structures is proved to be equivalent to SFP. Constructions such as the Plotkin powerdomain and the function space are provided, as well as a cpo (comple partial order) of such systems to give meanings to recursively defined domains.

Gender differences in reasoning ability measured by letter series items

Letter series and number series tests, consisting of items based on identical rules, were administered in a counterbalanced design to 320 (160 female and 160 male) undergraduates in order to investigate the gender differences in inductive reasoning ability measured by letter and number series tests. Results indicated that female college students obtained significantly higher (p<.05) means on letter series tests, but showed no such superiority on number series.

Identical rules do not make letter and number series equivalent

Letter series and number series tests, consisting of items based on identical rules, were administered in a counterbalanced design to 320 undergraduates in order to determine their comparability by testing the equality of (a) means, (b) variances, and (c) validity coefficients. Results indicated that the letter and number series tests, in which each item in one had a same-rule counterpart in the other, were not equivalent because they did not satisfy one or more of the criteria. Number series tests have higher means ( p < .001) and lower variances and covariances ( p < .01) than the corresponding letter series forms.

Influence of CpG Methylation and Target Spacing on V(D)J Recombination in a Transgenic Substrate

We have previously described a line of transgenic mice with multiple head-to-tail copies of an artificial V-J recombination substrate and have shown that the methylation of this transgene is under the control of a dominant strain-specific modifier gene, Ssm-1. When the transgene array is highly methylated, no recombination is detectable, but when it is unmethylated, V-J joining is seen in the spleen, bone marrow, lymph nodes, and Peyer's patches but not in the thymus or nonlymphoid tissues, including brain tissue. Strikingly, in mice with partially methylated transgene arrays, rearrangement preferentially occurs in hypomethylated copies. Therefore, V-J recombination is negatively correlated with methylated DNA sequences. In addition, it appears that recombination occurs randomly between any two recombination signal sequences within the transgene array. This lack of target preference in an unselectable array of identical targets rules out simple mechanisms of one-dimensional tracking of a V(D)J recombinase complex.

Influence of CpG methylation and target spacing on V(D)J recombination in a transgenic substrate.

We have previously described a line of transgenic mice with multiple head-to-tail copies of an artificial V-J recombination substrate and have shown that the methylation of this transgene is under the control of a dominant strain-specific modifier gene, Ssm-1. When the transgene array is highly methylated, no recombination is detectable, but when it is unmethylated, V-J joining is seen in the spleen, bone marrow, lymph nodes, and Peyer's patches but not in the thymus or nonlymphoid tissues, including brain tissue. Strikingly, in mice with partially methylated transgene arrays, rearrangement preferentially occurs in hypomethylated copies. Therefore, V-J recombination is negatively correlated with methylated DNA sequences. In addition, it appears that recombination occurs randomly between any two recombination signal sequences within the transgene array. This lack of target preference in an unselectable array of identical targets rules out simple mechanisms of one-dimensional tracking of a V(D)J recombinase complex.

Translational regulation of the Escherichia coli threonyl-tRNA synthetase gene: Structural and functional importance of the thrS operator domains

Previous work showed that E coli threonyl-tRNA synthetase (ThrRS) binds to the leader region of its own mRNA and represses its translation by blocking ribosome binding. The operator consists of four distinct domains, one of them (domain 2) sharing structural analogies with the anticodon arm of the E coli tRNA Thr. The regulation specificity can be switched by using tRNA identity rules, suggesting that the operator could be recognized by ThrRS as a tRNA-like structure. In the present paper, we investigated the relative contribution of the four domains to the regulation process by using deletions and point mutations. This was achieved by testing the effects of the mutations on RNA conformation (by probing experiments), on ThrRS recognition (by footprinting experiments and measure of the competition with tRNA Thr for aminoacylation), on ribosome binding and ribosome/ThrRS competition (by toeprinting experiments). It turns out that: i) the four domains are structurally and functionally independent; ii) domain 2 is essential for regulation and contains the major structural determinants for ThrRS binding; iii) domain 4 is involved in control and ThrRS recognition, but to a lesser degree than domain 2. However, the previously described analogies with the acceptor-like stem are not functionally significant. How it is recognized by ThrRS reamins to be resolved; iv) domain 1, which contains the ribosome loading site, is not involved in ThrRS recognition. The binding of ThrRS probably masks the ribosome binding site by steric hindrance and not by direct contacts. This is only achieved when ThrRS interacts with both domains 2 and 4; and v) the unpaired domain 3, which connects domains 2 and 4, is not directly involved in ThrRS recognition. It should serve as an articulation to provide an appropriate spacing between domains 2 and 4. Furthermore, it is possibly involved in ribosome binding.

Does spatial scaling imply temporal scaling in sandpile type cellular automata?

We study the relationship between the spatial and temporal scaling in sandpile type cellular automata and show that in the thermodynamic limit, for a regular lattice with identical toppling rules except possibly at the system boundary together with a uniform but random probability distribution of particle addition, scaling in the size of the avalanche is a natural consequence. However, we find that this sort of temporal scaling behavior is in general very sensitive to the underlying probability distribution of the particle addition into the system. Hence the underlying probability distribution of particle addition can act as an external fine tuning parameter for the system to have scaling behavior.

The specificity of translational control switched with transfer RNA identity rules.

The interaction of Escherichia coli threonyl-transfer RNA (tRNA) synthetase with the leader sequence of its own messenger RNA inhibits ribosome binding, resulting in negative translational feedback regulation. The leader sequence resembles the substrate (tRNA(Thr)) of the enzyme, and the nucleotides that mediate the correct recognition of the leader and the tRNA may be the same. A mutation suggested by tRNA identity rules that switches the resemblance of the leader sequence from tRNA(Thr) to tRNA(Met) causes the translation of the threonyl-tRNA synthetase messenger RNA to become regulated by methionyl-tRNA synthetase. This identity swap in the leader messenger RNA indicates that tRNA identity rules may be extended to interactions of synthetases with other RNAs.

Molecular mimicry in translational control of E. coli threonyl-tRNA synthetase gene. Competitive inhibition in tRNA aminoacylation and operator-repressor recognition switch using tRNA identity rules.

We previously showed that: (i) E.coli threonyl-tRNA synthetase (ThrRS) binds to the leader of its mRNA and represses translation by preventing ribosome binding to its loading site; (ii) the translational operator shares sequence and structure similarities with tRNA(Thr); (iii) it is possible to switch the specificity of the translational control from ThrRS to methionyl-tRNA synthetase (MetRS) by changing the CGU anticodon-like sequence to CAU, the tRNA(Met) anticodon. Here, we show that the wild type (CGU) and the mutated (CAU) operators act as competitive inhibitors of tRNA(Thr) and tRNA(fMet) for aminoacylation catalyzed by E.coli ThrRS and MetRS, respectively. The apparent Kd of the MetRS/CAU operator complex is one order magnitude higher than that of the ThrRS/CGU operator complex. Although ThrRS and MetRS shield the anticodon- and acceptor-like domains of their respective operators, the relative contribution of these two domains differs significantly. As in the threonine system, the interaction of MetRS with the CAU operator occludes ribosome binding to its loading site. The present data demonstrate that the anticodon-like sequence is one major determinant for the identity of the operator and the regulation specificity. It further shows that the tRNA-like operator obeys to tRNA identity rules.

The Substantial Identity Rule under the Japanese Novelty Standard

The Substantial Identity Rule under the Japanese Novelty Standard

Implementation benefits of C++ language mechanisms

C + + was designed by Bjarne Stroustrup at AT&amp;T Bell Laboratories in the early 1980s as an extension to the C language, providing data abstraction and object-oriented programming facilities. C + + provides a natural syntactic extension to C, incorporating the class construct from Simula. A design principle was to remain compatible and comparable with C in terms of syntax, performance and portability Another goal was to define an object-oriented language that significantly increased the amount of static type checking provided, with user-defined types (classes) and built-in types being part of a single unified type system obeying identical scope, allocation and naming rules. These aims have been achieved, providing some underlying reasons why C + + has become so prevalent in the industry. The approach has allowed a straightforward evolution from existing C-based applications to the new facilities offered by C + + , providing an easy transition for both software systems and programmers. The facilities described are based on Release 2.0 of the language, the version on which the ANSI and IS0 standardization of C + + is being based.

Symbolically Automated Direct Kinematic Equations Solver for Robotic Manipulators

SUMMARYSolving the direct kinematic problem in a symbolic form requires a laborious process of successive multiplications of the link homogeneous transformation matrices and involves a series of algebraic and trigonometric simplifications. The manual production of such solutions is tedious and error-prone. Due to the efficiency of theProloglanguage in symbolic processing, a rule–basedPrologprogram is developed to automate the creation of the following processes: Link transformation matrices; forward kinematic solutions; and the Jacobian matrix. This paper presents the backward recursive formulation techniques, the trigonometric identity rules, and some heuristic rules for implementing the System. A verification of the System has been demonstrated in case of several industrial robots.

Systems of correlations in rule and category learning: Use of structured input in learning syntactic categories

Abstract Three studies with artificial grammars investigated one property of natural language and one learning procedure which capitalises on this property to aid learning. Learning syntax is difficult because the rules and categories of syntax form a mutually defining system. Structural analogies to other systems (e.g. semantics, interaction) are limited and unreliable. On the other hand, treating syntax as a formal system and applying distributional analysis poses an extremely difficult learning problem. The property investigated is systematicity, coherence among multiple interpredictive features marking syntactic categories. The learning procedure is a method for directing attention to predictive features. This procedure predicts that an individual correlational rule or pattern will be learned more easily when it is part of a system of rules among intercorrelated features than when the identical rule occurs in isolation—complexity facilitates learning. The artificial grammar experiments varied the stru...

Strict cyclicity and elsewhere

This paper seeks to re-open the discussion of the status of the Strict Cycle Condition in Lexical Phonology by arguing that this constraint on cyclic rules is derivative from the Elsewhere Condition. A previous proposal to this effect (Kiparsky (1982)) had relied on poorly motivated identity rules; here, the blocking of cyclic rules in underived environments is achieved by a root → word rule instead. This rule, it is argued, is independently required for the transition from the root-based morphology of the cyclic stratum to the word-based morphology of the postcyclic stratum.

ON THE DERIVATION OF FLOW RULES FOR GRANULAR MATERIALS BASED ON DISSIPATION FUNCTIONS

Motivated by Ziegler's extremum principle, the author proposed a new hypothesis which leads to flow rules for granular materials as well as stress-dilatancy relationships. In this theory, the dissipation function has some specific characters so that the dissipation mechanism of friction can be taken into account. The simplest form of the function is obtained by generalizing Roscoe's dissipation energy and it gives the identical flow rule with Levy-Mises relation for the metal plasticity. Another type of dissipation function is introduced through the microscopical consideration of frictional energy in granular assemblies. The corresponding flow rule seems agreeable with the plastic behaviors of granular materials observed through experiments in the past.

Pattern Recognition Invariance in Pigeons (&lt;em&gt;Columbia Livia&lt;/em&gt;): Outline, Color and Contrast

Pigeons that had extensive training with an oddity-frona-sample discrimination procedure using visual patterns, and that could transfer their performance to novel patterns, were tested for three kinds of pattern recognition invariance. In one invariance experiment the sample stimuli were silhouette shapes and the comparison stimuli were outline figures. In another experiment the samples were white shapes on a dark background whereas the comparisons were black shapes on a bright background. In a third experiment the sample and comparison shapes were of different color. All the shapes used for invariance testing were novel to the pigeons. Performance during the tests was above 90% correct except in the case of the reversed contrast experiment, where it reached only 77/6; dazzling and/or attention problems may have been a disturbing factor. Even in this condition, however, significant transfer was obtained. Generally the pigeons showed that they are capable of invariant shape recognition under all three conditions. Since all critical tests involved shapes that were novel to the subjects the results also confirmed that pigeons can conceptualize a relational oddity/ identity rule.

Dynamical competition between reactive and reactive detachment channels in X − + H 2 colliding systems (X = Cl, Br, I)

Two reactive processes are observed: X − + H 2 → XH + H − (R) and X − + H 2 → XH + H + e − (RD). The angular and energy distributions of the molecular XH products are measured at collision energies varying from 5 to 10 eV center of mass. These distributions obey identical rules in the three systems: (a) XH molecules formed by both R and RD processes are scattered at the same c.m. angle, respectively 55° ±10 for ClH, 80° ±20 for BrH and 90° ±20 for IH. (b) The rovibrational energy of the XH molecules, when formed by R processes, is limited to a small amount: ⩽ 2 eV for ClH, ⩽ 1.5 eV for BrH, ⩽ 1 eV for IH, whereas when formed by RD it extends to the highest amount available from the collision energy, up to the dissociation limit. The RD process is not observed experimentally in the I −/H 2 system. This dynamical behaviour is fully understood in terms of non-adiabatic interaction between the two lowest [XH 2] − ionic surfaces, but the reason of the angular anisotropy is still not well understood.