The Two Phases of the Simplex Method: Theoretical Results Proved by Application of the Simplex Method

Author(s):  
Michel Sakarovitch
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takahiro Sakamoto ◽  
Hideki Innan

Abstract The turnover of sex-determining loci has repeatedly occurred in a number of species, rather than having a diverged pair of sex chromosomes. We model the turnover process by considering a linked locus under sexually antagonistic selection. The entire process of a turnover may be divided into two phases, which are referred to as the stochastic and deterministic phases. The stochastic phase is when a new sex-determining allele just arises and is still rare and random genetic drift plays an important role. In the deterministic phase, the new allele further increases in frequency by positive selection. The theoretical results currently available are for the deterministic phase, which demonstrated that a turnover of a newly arisen sex-determining locus could benefit from selection at a linked locus under sexually antagonistic selection, by assuming that sexually antagonistic selection works in a form of balancing selection. In this work, we provide a comprehensive theoretical description of the entire process from the stochastic phase to the deterministic phase. In addition to balancing selection, we explore several other modes of selection on the linked locus. Our theory allows us make a quantitative argument on the rate of turnover and the effect of the mode of selection at the linked locus. We also performed simulations to explore the pattern of polymorphism around the new sex-determining locus. We find that the pattern of polymorphism is informative to infer how selection worked through the turnover process.


Author(s):  
SIMONA BERTOLINI ◽  

Interest in the ontological constitution of living beings (with particular reference to the human being) characterizes the whole development of Hedwig Conrad-Martius’ philosophy. Several works written by the philosopher over the years deal with both the phenomenological description and the ontological foundation of the difference between plants, animals, and humans. Specifically, the ontological structure of the human being is investigated as a layered structure which presupposes those of plants and animals while overcoming them in a more complex and spiritual unity, on which human freedom and human knowledge depend. Although this topic maintains a crucial role in Conrad-Martius’ thought, the way the philosopher addresses it and the theoretical results of her phenomenological-ontological inquiry about it do not remain unchanged. Indeed, the ontological structure at the basis of phenomenal differences as well as the metaphysical foundations of this structure change over the decades. This paper aims at distinguishing between two phases, characterized by different ontological categories, through which Conrad-Martius’ anthropology and biological ontology develop. In the first phase, at the beginning of the twenties (precisely in her work Metaphysical Dialogues), the essential differences between plants, animals, and humans are explained with reference to a vital origin preceding the constitution of reality; to describe it Conrad-Martius employs terms such as “abyss” and “under-earthly realm.” In the second phase, exemplified by some writings published in the forties and the fifties, the reference to such a dimension disappears and the eidetic variety within the living world, including human specificity, is exclusively traced back to the finalistic substantiation of essences in the natural beings.


2011 ◽  
Vol 383-390 ◽  
pp. 2287-2292
Author(s):  
Yong Yuan Wang ◽  
Sheng Hui Liu ◽  
Wen Ze Liu ◽  
Ke Ying Wang

The shunt power capacitors are used as a reactive compensator while vacuum circuit breakers are used to switch shunt capacitors in power grid. To research the high over-voltage during switching off the shunt capacitors and a vacuum circuit beaker restriked, the restriking model is built with three-phase vacuum circuit breakers, considering the capacitors’ energy storage characteristic and asynchronous operating. The over-voltage is harmful to the insulation and life-circle of the equipments and even threatens power system safe and stabile operation. The variation trends of both recovery voltage between the contacts and the capacitors voltage are theoretically deduced. The model based on a 220kV substation of Guangdong grid was built and the most serious case that breakers are restriked in two phases are numbered with EMTP. Compared with theoretical results, simulation results are valid and practical.


2002 ◽  
Vol 16 (25) ◽  
pp. 3855-3863 ◽  
Author(s):  
QINGZHONG XUE

Considering the interface effect between two phases in composite, we present a novel model of dielectric constant of two-phase composites with interfacial shells. Starting from Maxwell theory and average polarization theory, the formula of calculating the effective dielectric constant of two-phase random composites with interfacial shells is presented. The theoretical results on effective dielectric constant of alkyd resin paint/Barium titanate random composites with interfacial shells are in good agreement with the experimental data.


2020 ◽  
Vol 45 (1/2) ◽  
pp. 103-120 ◽  
Author(s):  
Milad Ghelichkhani

Purpose This paper aims to trace the tectonic effects of openings as Heideggerian “built-things”. Design/methodology/approach This study has been organized in two phases. The first phase attempts to set up the theoretical framework through exploring the links between Heidegger’s notion of “built-thing” and contemporary tectonic discourses on dialectics between the values of matheme (construction, technology) and poetics (representation, meaning) to identify the key indicators in tectonic effects of openings. Accordingly, as the term “tectonic effects” is concerned with feelings and emotions that tectonics may evoke in people, the author searches for the indicators based on the poetic aspects of tectonic values and applies them within the phenomenological method implemented in the second phase of the research to explore the indicators in the designated case of the “Çavuşoğlu house”. Findings The results of this study indicate the significance of ontological nexus between tectonics as “poetic revealing” and the ability of the “built-thing” to generate tectonic effects within the embodied experience of dwellers. In fact, an opening can generate ontological tectonic effects in space only if it is brought about through a truthful build-dwell process which responds in a poetic way to the daily-life needs of the dwellers. The tangible examples of this fact are evident in the openings of the Çavuşoğlu house. Originality/value The theory of tectonics of openings as a separate “built-thing”, which is put forward in the present study, is a subject that has not been sufficiently studied so far and has the potential to be developed through further research. In light of this, the theoretical results of this study can contribute to tectonic thinking during the design process.


Filomat ◽  
2003 ◽  
pp. 169-176
Author(s):  
Nebojsa Stojkovic ◽  
Predrag Stanimirovic ◽  
Marko Petkovic

We analyze the problem of finding the first basic solution in the two phases simplex algorithm. Also, a modification and several improvements of the simplex method are introduced. We report computational results on numerical examples from Netlib test set.


1982 ◽  
pp. 62-75
Author(s):  
L. S. Srinath
Keyword(s):  

Author(s):  
Dongming Gan ◽  
Jorge Dias ◽  
Lakmal D. Seneviratne

This paper presents the topology variation of a 3(rT)PS metamorphic parallel mechanism which can change its mobility from 3 to 6. The reconfiguration stems from a reconfigurable (rT)PS limb of which the two phases can be unified by taking one as a special case of the other. Based on this, unified inverse kinematics is solved and a unified dynamics modeling is built using screw theory which naturally represents the geometric constraint and actuation forces in the same manner. The obtained modeling covers all the topologies of the parallel mechanism. A numerical example demonstrates the theoretical results which provide basis for this metamorphic parallel robot with applications in reconfiguration-required environment.


2020 ◽  
Author(s):  
T. Sakamoto ◽  
H. Innan

ABSTRACTSome species undergo frequent turnovers of sex-determining locus, rather than having stable diverged sex chromosomes. In such species, how often turnover occurs is a fundamental evolutionary question. We model the process with considering a linked locus under sexually antagonistic selection. The entire process of a turnover may be divided into two phases, which are referred to as the stochastic and deterministic phases. The stochastic phase is when a new sex-determining allele just arises and is still rare and random genetic drift plays an important role. In the deterministic phase, the new allele further increases in frequency by positive selection. The theoretical results currently available are for the deterministic phase, which demonstrated that a turnover of a newly arisen sex determining locus could benefit from selection at a linked locus under sexually antagonistic selection, by assuming that sexually antagonistic selection works in a form of balancing selection. In this work, we provide a comprehensive theoretical description of the entire process from the stochastic phase to the deterministic phase. In addition to balancing selection, we explore several other modes of selection on the linked locus. Our theory allows us make a quantitative argument on the rate of turnover and the effect of the mode of selection at the linked locus. We also performed simulations to explore the pattern of polymorphism around the new sex determining locus. We find that the pattern of polymorphism is informative to infer how selection worked through the turnover process.


Author(s):  
A. Garg ◽  
R. D. Noebe ◽  
R. Darolia

Small additions of Hf to NiAl produce a significant increase in the high-temperature strength of single crystals. Hf has a very limited solubility in NiAl and in the presence of Si, results in a high density of G-phase (Ni16Hf6Si7) cuboidal precipitates and some G-platelets in a NiAl matrix. These precipitates have a F.C.C structure and nucleate on {100}NiAl planes with almost perfect coherency and a cube-on-cube orientation-relationship (O.R.). However, G-phase is metastable and after prolonged aging at high temperature dissolves at the expense of a more stable Heusler (β'-Ni2AlHf) phase. In addition to these two phases, a third phase was shown to be present in a NiAl-0.3at. % Hf alloy, but was not previously identified (Fig. 4 of ref. 2 ). In this work, we report the morphology, crystal-structure, O.R., and stability of this unknown phase, which were determined using conventional and analytical transmission electron microscopy (TEM).Single crystals of NiAl containing 0.5at. % Hf were grown by a Bridgman technique. Chemical analysis indicated that these crystals also contained Si, which was not an intentional alloying addition but was picked up from the shell mold during directional solidification.


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