Uncontrolled control variables: The extent that a researcher’s degrees of freedom with control variables increases various types of statistical errors.

AbstractA hypothesis about sensorimotor integration (the λ model) is described and applied to movement control and kinesthesia. The central idea is that the nervous system organizes positional frames of reference for the sensorimotor apparatus and produces active movements by shifting the frames in terms of spatial coordinates. Kinematic and electromyographic patterns are not programmed, but emerge from the dynamic interaction among the system s components, including external forces within the designated frame of reference. Motoneuronal threshold properties and proprioceptive inputs to motoneurons may be cardinal components of the physiological mechanism that produces positional frames of reference. The hypothesis that intentional movements are produced by shifting the frame of reference is extended to multi-muscle and multi-degrees-of-freedom systems with a solution of the redundancy problem that allows the control of a joint alone or in combination with other joints to produce any desired limb configuration and movement trajectory. The model also implies that for each motor behavior, the nervous system uses a strategy that minimizes the number of changeable control variables and keeps the parameters of these changes invariant. Examples are provided of simulated kinematic and electromyographic signals from single- and multi-joint arm movements produced by suggested patterns of control variables. Empirical support is provided and additional tests of the model are suggested. The model is contrasted with others based on the ideas of programming of motoneuronal activity, muscle forces, stiffness, or movement kinematics.

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Control Variables in Leadership Research: A Qualitative and Quantitative Review

Journal of Management ◽

10.1177/0149206317690586 ◽

2017 ◽

Vol 44 (1) ◽

pp. 131-160 ◽

Cited By ~ 27

Author(s):

Jeremy B. Bernerth ◽

Michael S. Cole ◽

Erik C. Taylor ◽

H. Jack Walker

Keyword(s):

Degrees Of Freedom ◽

Meta Analysis ◽

Control Variable ◽

Parameter Estimates ◽

Statistical Control ◽

Leadership Studies ◽

Control Variables ◽

Quantitative Review ◽

Current State ◽

Leadership Research

Statistical control of extraneous (i.e., third) variables is a common analytic tool among leadership researchers. While such a strategy is typically assumed to prove beneficial, it can actually introduce various complications that are underestimated or even ignored. This study investigates and summarizes the current state of control variable usage in leadership research by qualitatively and quantitatively examining the use of statistical control variables in 10 highly regarded management and applied psychology journals. Despite available “best practices,” our results indicate that control variable usage in existing leadership studies is rarely grounded in theory but instead frequently relies on outdated misconceptions. Moreover, a meta-analysis of the relationships between popular control variables and leadership constructs finds nearly universal weak effect sizes, suggesting that many studies may not only be losing valuable degrees of freedom but also making inferences based on biased parameter estimates. To address these issues, we put forth a number of recommendations to assist leadership scholars with determining whether potential third variables should be controlled for in their leadership research.

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Dynamic multi-patch isogeometric analysis of planar Euler-Bernoulli beams

10.31219/osf.io/t8urg ◽

2021 ◽

Author(s):

Duy Vo ◽

Aleksandar Borković ◽

Pruettha Nanakorna ◽

Tinh Quoc Bui

Keyword(s):

Dynamic Analysis ◽

Degrees Of Freedom ◽

Simple Relation ◽

Bernoulli Beam ◽

Control Variables ◽

Cross Sectional ◽

Beam Structures ◽

And Performance ◽

And Control ◽

Euler Bernoulli Beam

This study presents a novel isogeometric Euler-Bernoulli beam formulation for in-plane dynamic analysis of multi-patch beam structures. The kinematic descriptions involve only displacements of the beam axis, which are approximated by non-uniform rational B-spline (NURBS) curves. Translational displacements of the control points are here considered as control variables. The motivation of this work is to propose a penalty-free method to handle in-plane dynamic analysis of multi-patch beam structures. A simple relation between cross-sectional rotations at the ends of the beams and control variables is derived, allowing the incorporation of the end rotations as degrees of freedom. This improved setting can straightforwardly tackle beam structures with many rigid multi-patch connections, a major challenging issue when using existing isogeometric Euler-Bernoulli beam formulations. Additionally, rotational boundary conditions are conveniently prescribed. Numerical examples with complicated beam structures such as circular arches and frames with kinks are considered to show the accuracy and performance of the developed formulation. The computed results are verified with those derived from the conventional finite element method, and the superior convergence properties of the proposed formulation are illustrated. We additionally discuss about the possible extension of the present approach to spatial beam structures.

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The motion of a lunar orbiter

Symposium - International Astronomical Union ◽

10.1017/s0074180900105686 ◽

1966 ◽

Vol 25 ◽

pp. 373

Author(s):

Y. Kozai

Keyword(s):

Degrees Of Freedom ◽

Dimensional Space ◽

Artificial Satellite ◽

Equations Of Motion ◽

Triaxial Ellipsoid ◽

The Moon ◽

Secular Motion ◽

The Earth ◽

Close Satellite ◽

The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

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Representing utility and deploying the body

Behavioral and Brain Sciences ◽

10.1017/s0140525x19001602 ◽

2020 ◽

Vol 43 ◽

Author(s):

David Spurrett

Keyword(s):

Functional Activity ◽

Degrees Of Freedom ◽

The Body ◽

Target Article ◽

Processing Demands ◽

The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

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Das Experten-Novizen-Paradigma und die Vertrauenskrise in der Psychologie

Zeitschrift für Sportpsychologie ◽

10.1026/1612-5010/a000174 ◽

2016 ◽

Vol 23 (4) ◽

pp. 131-140 ◽

Cited By ~ 3

Author(s):

Philip Furley ◽

Karsten Schul ◽

Daniel Memmert

Keyword(s):

Degrees Of Freedom

Zusammenfassung. Das Ziel des vorliegenden Beitrages ist es anhand eines vielverwendeten Paradigmas in der Sportwissenschaft – dem Experten-Novizen-Vergleich – zu prüfen, ob die momentane Vertrauenskrise in der Psychologie ebenfalls die Sportpsychologie betreffen könnte. Anhand einer exemplarischen Studie zeigen wir, dass es innerhalb dieses Paradigmas zu kontroversen Befunden kommt, welche durch die vermuteten Ursachen der Vertrauenskrise (Researcher Degrees of Freedom, kleine Stichprobengrößen) erklärt sein könnten. Zusätzlich argumentieren wir, dass weitere Faktoren (Konfundierung, Stichprobengrößen, Rosenthal Effekt, Expertise-Definition) innerhalb dieses Paradigmas die Reproduzierbarkeit von Erkenntnissen in Frage stellen. Wir diskutieren mögliche Maßnahmen, wie die dargestellten Probleme des Experten-Novizen-Paradigmas in zukünftigen Forschungsarbeiten gelöst werden können.

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