GEOMETRY OF VIBRATIONAL STABILIZATION AND SOME APPLICATIONS

2005 ◽  
Vol 15 (09) ◽  
pp. 2747-2756 ◽  
Author(s):  
MARK LEVI
Keyword(s):  
Acoustic Waves ◽  
Nonholonomic System ◽  
Nonholonomic Constraint ◽  
Constraint Forces ◽  
Suspension Point ◽  
Higher Dimensional ◽  
Vibrational Stabilization ◽  
Close Relationship ◽  
The One ◽  
Pursuit Curve

This paper gives a short overview of various applications of stabilization by vibration, along with the exposition of the geometrical mechanism of this phenomenon. More specifically, the following observation is described: a rapidly vibrated holonomic system can be approximated by a certain associated nonholonomic system. It turns out that effective forces in some rapidly vibrated (holonomic) systems are the constraint forces of an associated auxiliary nonholonomic constraint. In particular, we review a simple but remarkable connection between the curvature of the pursuit curve (the tractrix) on the one hand and the effective force on the pendulum with vibrating support. The latter observation is a part of a recently discovered close relationship between two standard classical problems in mechanics: (1) the pendulum whose suspension point executes fast periodic motion along a given curve, and (2) the Chaplygin skate (known also as the Prytz planimeter, or the "bicycle"). The former is holonomic, the latter is nonholonomic. The holonomy of the skate shows up in the effective motion of the pendulum. This relationship between the pendulum with a twirled pivot and the Chaplygin skate has somewhat unexpected physical manifestations, such as the drift of suspended particles in acoustic waves. Finally, a higher-dimensional example of "geodesic motion" on a vibrating surface is described.

scholarly journals An Argument Against Augmenting the Lagrangean for Nonholonomic Systems

2009 ◽  
Vol 76 (3) ◽  
Author(s):  
Carlos M. Roithmayr ◽  
Dewey H. Hodges
Keyword(s):  
Nonholonomic System ◽  
Nonholonomic Constraint ◽  
Equations Of Motion ◽  
Nonholonomic Systems ◽  
Euler Method ◽  
Constraint Forces ◽  
Dynamical Equations ◽  
New Approach ◽  
Constraint Equations ◽  
Kane's Method

Although it is known that correct dynamical equations of motion for a nonholonomic system cannot be obtained from a Lagrangean that has been augmented with a sum of the nonholonomic constraint equations weighted with multipliers, previous publications suggest otherwise. One published example that was proposed in support of augmentation purportedly demonstrates that an accepted method fails to produce correct equations of motion whereas augmentation leads to correct equations. This present paper shows that, in fact, the opposite is true. The correct equations, previously discounted on the basis of a flawed application of the Newton–Euler method, are verified by using Kane’s method together with a new approach for determining the directions of constraint forces.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

Albrecht Durer and the 16TH Century Melancholy

2020 ◽  
Vol 2 ◽  
pp. 37-49
Author(s):  
Marcel Henrique Rodrigues
Keyword(s):  
Religious Culture ◽  
The Other ◽  
16Th Century ◽  
Other Hand ◽  
Close Relationship ◽  
The One ◽  
Deep Sense

Little has been discussed in academia about the close relationship between the Renaissance of the 16th century and melancholy humor, and esoteric elements arising mainly from Florentine Neoplatonism. The link between melancholy and esotericism becomes very clear when we analyze the gravure “Melencolia I” by Albrecht Dürer (1471-1528), composed of a significant number of symbols that refer to an esoteric religious culture that then emerged. Renaissance melancholy gained several nuances. On the one hand, it was considered a sin, a despicable mood characteristic of witches; on the other hand, a deep sense of inspiration typical of men of “genius”. This ambivalence also occurred in the firmament, as the melancholic people were guided by the dark planet Saturn, according to astrological belief. We also have the cultural scenario of the 16th century, especially in Dürer's Germany, which contributed to strengthening the melancholy issues.

scholarly journals Higher Dimensional Holonomy Map for Rules Submanifolds in Graded Manifolds

2020 ◽  
Vol 8 (1) ◽  
pp. 68-91
Author(s):  
Gianmarco Giovannardi
Keyword(s):  
Characteristic Direction ◽  
Fixed Degree ◽  
One Dimensional ◽  
First Order ◽  
Natural Choice ◽  
Higher Dimensional ◽  
Graded Manifold ◽  
The One ◽  
Graded Manifolds ◽  
Holonomy Map

AbstractThe deformability condition for submanifolds of fixed degree immersed in a graded manifold can be expressed as a system of first order PDEs. In the particular but important case of ruled submanifolds, we introduce a natural choice of coordinates, which allows to deeply simplify the formal expression of the system, and to reduce it to a system of ODEs along a characteristic direction. We introduce a notion of higher dimensional holonomy map in analogy with the one-dimensional case [29], and we provide a characterization for singularities as well as a deformability criterion.

scholarly journals LIGHT COMPOSITE HIGGS: LCH @ LHC

2005 ◽  
Vol 20 (27) ◽  
pp. 6133-6148 ◽  
Author(s):  
FRANCESCO SANNINO
Keyword(s):  
Gauge Group ◽  
Higgs Mass ◽  
Cold Dark Matter ◽  
Precision Measurements ◽  
Chiral Phase ◽  
Symmetric Representation ◽  
Composite Higgs ◽  
Higher Dimensional ◽  
The One ◽  
Intrinsic Scale

Here I summarize some of the salient features of technicolor theories with technifermions in higher dimensional representations of the technicolor gauge group. The expected phase diagram as function of number of flavors and colors for the two index (anti)symmetric representation of the gauge group is reviewed. After having constructed the simplest walking technicolor theory one can show that it is not at odds with the precision measurements. The simplest theory also requires, for consistency, a fourth family of heavy leptons. The latter may result in an interesting signature at LHC. In the case of a fourth family of leptons with ordinary lepton hypercharge the new heavy neutrino can be a natural candidate of cold dark matter. New theories will also be proposed in which the critical number of flavors needed to enter the conformal window is higher than in the one with fermions in the two-index symmetric representation, but lower than in the walking technicolor theories with fermions only in the fundamental representation of the gauge group. Due to the near conformal/chiral phase transition the composite Higgs is very light compared to the intrinsic scale of the technicolor theory. For the two technicolor theory the composite Higgs mass is predicted not to exceed 150 GeV.

Dreams of Truck Drivers: A Test of the Continuity Hypothesis of Dreaming

2005 ◽  
Vol 25 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Michael Schredl ◽  
Arthur Funkhouser ◽  
Nicole Arn
Keyword(s):  
Empirical Studies ◽  
Truck Drivers ◽  
The Other ◽  
Continuity Hypothesis ◽  
Future Studies ◽  
Daytime Activity ◽  
Close Relationship ◽  
The One ◽  
Dream Emotions ◽  
The Relationship

Empirical studies largely support the continuity hypothesis of dreaming. The present study investigated the frequency and emotional tone of dreams of truck drivers. On the one hand, the findings of the present study partly support the continuity regarding the time spent with driving/being in the truck and driving dreams and, on the other hand, a close relationship was found between daytime mood (feelings of stress, job satisfaction) and dream emotions, i.e., different dream characteristics were affected by different aspects of daytime activity. The results, thus, indicate that it is necessary to define very clearly how this continuity is to be conceptualized. The approach of formulating a mathematical model (cf. [1]) should be adopted in future studies in order to specify the factors and their magnitude in the relationship between waking and dreaming.

scholarly journals STUDIES ON THE ETIOLOGY OF RABBIT POX

1936 ◽  
Vol 63 (3) ◽  
pp. 353-378 ◽  
Author(s):  
Ch'uan-K'uei Hu ◽  
Paul D. Rosahn ◽  
Louise Pearce
Keyword(s):  
New York ◽  
Clinical Manifestations ◽  
Vaccine Virus ◽  
Intradermal Injection ◽  
Skin Area ◽  
Cutaneous Lesions ◽  
Active Growth ◽  
Specific Relationship ◽  
Close Relationship ◽  
The One

Experiments are reported in which it was shown that rabbits which had recovered from experimental or spontaneous rabbit pox were refractory to inoculation of pox virus injected by various routes, and in addition did not develop clinical manifestations of the disease under conditions of exposure to florid cases of pox. It was found that pox recovered rabbits were susceptible to inoculation with the virus of virus III disease of rabbits and that virus III recovered rabbits could be successfully inoculated with pox virus. Furthermore, virus III recovered rabbits developed pox when subjected to room exposure in the same manner as did normal rabbits. It thus appears that there is no specific relationship between the two viruses. Rabbits which had recovered from experimental or spontaneous pox were found to be just as susceptible to inoculation with the virus of infectious myxoma of rabbits as were normal rabbits, a result which demonstrates that there is no specific relationship between these viruses. Rabbits which had recovered from experimental or spontaneous pox were refractory to inoculation with culture dermovaccine virus, but vaccine recovered rabbits were not completely refractory to inoculation with pox virus. Under conditions of exposure to clinical cases of pox, adult vaccine immune rabbits did not develop clinical manifestations of pox, but young, recently weaned vaccinated rabbits did contract mild but definite clinical pox. Experimental pox recovered rabbits were partially refractory to inoculation with neurovaccine virus and neurovaccine recovered rabbits were partially refractory to inoculation with pox virus. The refractory condition of the pox immune rabbits appeared to be more pronounced than that of the neurovaccine immunes. The cutaneous lesions which developed from the intradermal injection of pox, neurovaccine, and culture vaccine viruses showed definite differences with respect to the rate and persistence of active growth, amount of edema, hemorrhage, and necrosis, and the degree of tissue destructiveness. These features were most pronounced in the lesions of pox virus and were least marked in the lesions of culture vaccine virus. The differences were particularly apparent in normal rabbits, but they were also present in the lesions which developed in immune animals. It was found that the calf was susceptible to inoculation with pox virus applied to a scarified skin area. There were many similarities in the appearance and course of the pox lesions to those resulting from culture vaccine virus, the New York Board of Health vaccine, and neurovaccine virus similarly inoculated. But the pox lesions were most numerous, much the largest and most destructive, and by far the most persistent while next in order were those of the Board of Health dermovaccine. The results of these various experiments showed that a close relationship obtains between pox virus, on the one hand, and vaccine virus and neurovaccine virus, on the other, but it cannot be said that pox virus is identical in all respects with either one of these viruses. The findings indicated that the relationship between pox and neurovaccine viruses is closer than that between pox and culture vaccine viruses. Upon the basis of the results observed in culture (dermo) vaccine immune rabbits inoculated with or exposed to pox, it appeared that vaccination with vaccine virus offered a method of protection against rabbit pox.

A Graphical Exposition of the Ising Problem

1971 ◽  
Vol 12 (3) ◽  
pp. 365-377 ◽  
Author(s):  
Frank Harary
Keyword(s):  
Dimensional Case ◽  
Two Dimensional ◽  
One Dimensional ◽  
Higher Dimensional ◽  
The One

Ising [1] proposed the problem which now bears his name and solved it for the one-dimensional case only, leaving the higher dimensional cases as unsolved problems. The first solution to the two dimensional Ising problem was obtained by Onsager [6]. Onsager's method was subsequently explained more clearly by Kaufman [3]. More recently, Kac and Ward [2] discovered a simpler procedure involving determinants which is not logically complete.

scholarly journals Defeasibility, Law, and Argumentation: A Critical View from an Interpretative Standpoint

Argumentation ◽  
2020 ◽  
Author(s):  
Francesca Poggi
Keyword(s):  
Explanatory Power ◽  
The Other ◽  
Legal Argumentation ◽  
Legal Interpretation ◽  
Central Theme ◽  
Critical View ◽  
Legal Literature ◽  
Close Relationship ◽  
The One ◽  
Definition Of

AbstractThe phenomenon of defeasibility has long been a central theme in legal literature. This essay aims to shed new light on that phenomenon by clarifying some fundamental conceptual issues. First, the most widespread definition of legal defeasibility is examined and criticized. The essay shows that such a definition is poorly constructed, inaccurate and generates many problems. Indeed, the definition hides the close relationship between legal defeasibility and legal interpretation. Second, this essay argues that no new definition is needed. I will show that from an interpretative standpoint, there is nothing special about legal defeasibility. Contrary to what some authors maintain, no unique or privileged source of legal defeasibility exists, nor are there privileged arguments to justify it. Specifically, legal defeasibility refers to interpretative outcomes deriving from interpretative arguments that, on the one hand, are very different from one another, and, on the other, are often employed to justify different interpretative outcomes. In the legal field, the problems related to defeasibility have little in common with the problems that this label covers in other areas—such as logic or epistemology—and they are nothing but the well-known problems related to legal interpretation. In conclusion, this paper argues that as far as legal argumentation is concerned, the notion of legal defeasibility lacks explanatory power, and it should be abandoned.

scholarly journals Simple framework for constructing functional spiking recurrent neural networks

2019 ◽  
Vol 116 (45) ◽  
pp. 22811-22820 ◽  
Author(s):  
Robert Kim ◽  
Yinghao Li ◽  
Terrence J. Sejnowski
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Continuous Variable ◽  
Model Parameters ◽  
Additional Parameter ◽  
Wide Range ◽  
Close Relationship ◽  
Rate Coding ◽  
One To One ◽  
The One

Cortical microcircuits exhibit complex recurrent architectures that possess dynamically rich properties. The neurons that make up these microcircuits communicate mainly via discrete spikes, and it is not clear how spikes give rise to dynamics that can be used to perform computationally challenging tasks. In contrast, continuous models of rate-coding neurons can be trained to perform complex tasks. Here, we present a simple framework to construct biologically realistic spiking recurrent neural networks (RNNs) capable of learning a wide range of tasks. Our framework involves training a continuous-variable rate RNN with important biophysical constraints and transferring the learned dynamics and constraints to a spiking RNN in a one-to-one manner. The proposed framework introduces only 1 additional parameter to establish the equivalence between rate and spiking RNN models. We also study other model parameters related to the rate and spiking networks to optimize the one-to-one mapping. By establishing a close relationship between rate and spiking models, we demonstrate that spiking RNNs could be constructed to achieve similar performance as their counterpart continuous rate networks.

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