An experimental study of strongly nonlinear waves in a rotating system

1987 ◽  
Vol 177 ◽  
pp. 381-394 ◽  
Author(s):  
Dominique P. Renouard ◽  
Gabriel Chabert D'Hières ◽  
Xuizhang Zhang
Keyword(s):  
Equilibrium Shape ◽  
Scaling Law ◽  
Maximum Amplitude ◽  
Rotating Platform ◽  
Coriolis Parameter ◽  
Rotating System ◽  
Height Variation ◽  
Experimental Conditions ◽  
Strongly Nonlinear ◽  
The Right

The influence of rotation upon internal solitary waves is studied in a (10 m × 2 m × 0.6 m) channel located on the large rotating platform at Grenoble University. We observe an intumescence which moves along the right-hand side of the channel with respect to its direction of propagation. Along the side, once the intumescence reaches its equilibrium shape, the height variation of the interface with time is correctly described by the sech2 function, and the characteristic KdV scaling law linking the maximum amplitude and the wavelength along the side is fulfilled. The intumescence is a stable phenomenon which moves as a whole without deformation apart from the viscous damping. For identical experimental conditions, the amplitude of the intumescence along the side increases with increasing Coriolis parameter, and at a given period of rotation of the platform, the celerity along the side increases with increasing amplitude. But for identical conditions, we found that the celerity along the side is equal to the celerity that the wave would have for such conditions without rotation. The amplitude of the intumescence in a plane perpendicular to the wall decreases exponentially with increasing distance from the side, but the crest of the wave is curved backward.

Dual Intentional Agency

2018 ◽  
Author(s):  
Elizabeth Schechter
Keyword(s):  
Left Hemisphere ◽  
Practical Reasoning ◽  
Right Hemisphere ◽  
Brain Surgery ◽  
Experimental Conditions ◽  
Split Brain ◽  
Intentional Agency ◽  
Intentional Agents ◽  
Experimental Findings ◽  
The Right

This chapter defends the 2-agents claim, according to which the two hemispheres of a split-brain subject are associated with distinct intentional agents. The empirical basis of this claim is that, while both hemispheres are the source or site of intentions, the capacity to integrate them in practical reasoning no longer operates interhemispherically after split-brain surgery. As a result, the right hemisphere-associated agent, R, and the left hemisphere-associated agent, L, enjoy intentional autonomy from each other. Although the positive case for the 2-agents claim is grounded mainly in experimental findings, the claim is not contradicted by what we know of split-brain subjects’ ordinary behavior, that is, the way they act outside of experimental conditions.

scholarly journals Behavioral Triggers of Skin Conductance Responses and Their Neural Correlates in the Primate Amygdala

2009 ◽  
Vol 101 (4) ◽  
pp. 1749-1754 ◽  
Author(s):  
Christopher M. Laine ◽  
Kevin M. Spitler ◽  
Clayton P. Mosher ◽  
Katalin M. Gothard
Keyword(s):  
Skin Conductance ◽  
Single Unit ◽  
Population Level ◽  
Emotional Reaction ◽  
Neural Population ◽  
Experimental Conditions ◽  
Indirect Measure ◽  
Skin Conductance Responses ◽  
The Right ◽  
Sympathetic Arousal

The amygdala plays a crucial role in evaluating the emotional significance of stimuli and in transforming the results of this evaluation into appropriate autonomic responses. Lesion and stimulation studies suggest involvement of the amygdala in the generation of the skin conductance response (SCR), which is an indirect measure of autonomic activity that has been associated with both emotion and attention. It is unclear if this involvement marks an emotional reaction to an external stimulus or sympathetic arousal regardless of its origin. We recorded skin conductance in parallel with single-unit activity from the right amygdala of two rhesus monkeys during a rewarded image viewing task and while the monkeys sat alone in a dimly lit room, drifting in and out of sleep. In both experimental conditions, we found similar SCR-related modulation of activity at the single-unit and neural population level. This suggests that the amygdala contributes to the production or modulation of SCRs regardless of the source of sympathetic arousal.

Broadband Combustion Noise Prediction With the Fast Random Particle Method

2014 ◽  
Author(s):  
Felix Grimm ◽  
Roland Ewert ◽  
Jürgen Dierke ◽  
Berthold Noll ◽  
Manfred Aigner
Keyword(s):  
Scaling Law ◽  
Particle Method ◽  
Reconstruction Algorithm ◽  
Combustion Noise ◽  
Frequency Noise ◽  
Noise Prediction ◽  
Data Set ◽  
Jet Flame ◽  
The Right ◽  
Random Particle

A new highly efficient, hybrid CFD/CAA approach for broadband combustion noise modeling is introduced. The inherent sound source generation mechanism is based on turbulent flow field statistics, which are determined from reacting RANS calculations. The generated sources form the right-hand side of the linearized Euler equations for the calculation of sound fields. The stochastic time-domain source reconstruction algorithm is briefly described with emphasis on two different ways of spatial discretization, RPM (Random Particle Method) and the newly developed FRPM (Fast RPM). The application of mainly the latter technique to combustion noise (CN) prediction and several methodical progressions are presented in the paper. (F)RPM-CN is verified in terms of its ability to accurately reproduce prescribed turbulence-induced one- and two-point statistics for a generic test and the DLR-A jet flame validation case. Former works on RPM-CN have been revised and as a consequence methodical improvements are introduced along with the progression to FRPM-CN: A canonical CAA setup for the applications DLR-A, -B and H3 flame is used. Furthermore, a second order Langevin decorrelation model is introduced for FRPM-CN, to avoid spurious high frequency noise. A new calibration parameter set for reacting jet noise prediction with (F)RPM-CN is proposed. The analysis shows the universality of the data set for 2D jet flame applications and furthermore the method’s accountance for Reynolds scalability. In this context, a Mach number scaling law is used to conserve Strouhal similarity of the jet flame spectra. Finally, the numerical results are compared to suitable similarity spectra.

Specificity of afferent and efferent regeneration in the cockroach: establishment of a reflex pathway between contralaterally homologous target cells

1978 ◽  
Vol 41 (4) ◽  
pp. 885-895 ◽  
Author(s):  
C. R. Fourtner ◽  
C. D. Drewes ◽  
T. W. Holzmann
Keyword(s):  
Motor Neuron ◽  
Temporal Analysis ◽  
Normal Activity ◽  
Monosynaptic Reflex ◽  
Target Cells ◽  
Experimental Conditions ◽  
Stimulus Interval ◽  
Experimental Procedure ◽  
Metathoracic Ganglion ◽  
The Right

1. In 132 cockroaches the main leg nerve on one side (right), of the metathoracic segment was crossed to the opposite (left) side and allowed to regenerate. In 3-8 wk, 59% of the animals displayed reflex activity in the left leg (behaviorally demonstrated by leg withdrawal following tarsal stimulation). 2. EMGs from the femoral extensor revealed potentials characteristic of normal activity in the extensor, which is innervated by an identified motor neuron, Ds. 3. Intracellular recordings from processes within the right hemiganglion of the metathoracic ganglion (CNS) demonstrated 1:1 activity between a unit in the CNS recording and the EMG of the left extensor. Subsequent intracellular staining revealed that the unit was on the right side of the CNS and was identified as motor neuron Ds by the location of its soma and dendrites. This finding indicated that specific, contralateral, efferent reinnervation occurs in the cockroach. 4. In normal cockroaches a monosynaptic reflex exists between hair plate afferents and Ds. A temporal analysis (stimulus-interval histogram) indicated that the reflex is also established in the crossed-regenerated animals. These data suggested that specific contralateral afferent reinnervation also occurs in the cockroach and that the monosynaptic nature of the normal reflex was reestablished. 5. Therefore, cell-to-cell specificity in neuron-to-neuron or neuron-to-muscle interactions not only occurs in normally developing or regenerating animals but also occurs between contralaterally homologous target cells, given the proper experimental conditions. It is also suggested that this experimental procedure of redesigning pathways may be a useful tool for further studies of behavior.

scholarly journals Gender Differences and Unfairness Processing during Economic and Moral Decision-Making: A fNIRS Study

2020 ◽  
Vol 10 (9) ◽  
pp. 647
Author(s):  
Maria Elide Vanutelli ◽  
Francesca Meroni ◽  
Giulia Fronda ◽  
Michela Balconi ◽  
Claudio Lucchiari
Keyword(s):  
Decision Making ◽  
Cortical Activation ◽  
Moral Decision Making ◽  
Experimental Conditions ◽  
Fairness Perception ◽  
Social And Emotional ◽  
Economic Decisions ◽  
Moral Choices ◽  
The Right ◽  
Social Decision Making

Decisional conflicts have been investigated with social decision-making tasks, which represent good models to elicit social and emotional dynamics, including fairness perception. To explore these issues, we created two modified versions of the UG framed within an economic vs. a moral context that included two kinds of unfair offers: advantageous (upside, U) or disadvantageous (downside, D) from the responder’s perspective, and vice-versa for the proponent. The hemodynamic activity of 36 participants, 20 females and 16 males, was continuously recorded with fNIRS to investigate the presence of general or specific circuits between the different experimental conditions. Results showed that disadvantageous offers (D) are associated with an increased widespread cortical activation. Furthermore, we found that advantageous moral choices at the expense of others (U) were related to the activation of the right prefrontal cortex. Finally, we found gender-related differences in brain activations in the different frameworks. In particular, the DLPFC was recruited by females during the economic task, and by males during the moral frame. In conclusion, the present study confirmed and expanded previous data about the role of the prefrontal cortices in decision-making, suggesting the need for further studies to understand better the different prefrontal networks serving moral and economic decisions also considering gender-related differences.

Contralateral renal function after unilateral renal vein ligation

1959 ◽  
Vol 197 (5) ◽  
pp. 1093-1096
Author(s):  
Joseph H. Perlmutt
Keyword(s):  
Renal Function ◽  
Renal Vein ◽  
Left Renal Vein ◽  
Free Water ◽  
Urine Osmolality ◽  
Tubular Reabsorption ◽  
Experimental Conditions ◽  
Free Water Clearance ◽  
Excretion Rates ◽  
The Right

The effect of increased pressure in one kidney, produced by ligation of its vein, on contralateral renal function was investigated in eight anesthetized dogs. Kidney function was determined under the same experimental conditions in five dogs, but without renal vein ligation. For the latter group, renal function, on the average, remained reasonably stable. After left renal vein ligation, findings for the right kidney were as follows: a) decreased urine flow, amounting maximally to 9.5–41.4% of control flows; b) slight increase of questionable significance in creatinine clearance; c) inconstant changes in PAH clearance; d) increase in urine osmolality to hypertonic values; e) decrease in solute-free water clearance; f) slight rise of questionable significance in total solute clearance; and g) either no change or inconstant changes in excretion rates Na+ and K+. The data indicate that the oliguria resulted solely from increased renal tubular reabsorption of water, suggesting liberation of antidiuretic hormone as the possible mechanism. Direct nervous influences on tubular reabsorption of water cannot, however, be presently ruled out.

The Momentum Imbalance Paradox Revisited

2005 ◽  
Vol 35 (10) ◽  
pp. 1928-1939 ◽  
Author(s):  
Doron Nof
Keyword(s):  
Momentum Flux ◽  
Classical Problem ◽  
Relative Vorticity ◽  
Rossby Number ◽  
Loop Current ◽  
Coriolis Parameter ◽  
Southern Boundary ◽  
Steady Current ◽  
The One ◽  
The Right

Abstract The classical problem of a point source situated along a southern boundary emptying buoyant water into a (β plane) ocean is revisited. Pichevin and Nof (PN) have shown that, in contrast to the view prevailing at the time, such an inviscid outflow does not simply turn to the right. Rather, it bifurcates into two branches: a steady branch that does turn to the right (eastward) and an unsteady branch that periodically sheds eddies to the left (westward). This partition is because a simple turn to the right of the entire outflow leaves the outflow’s long-shore momentum flux unbalanced, creating a paradox. In contrast, the branching allows the westward-drifting eddies (westward branch) to balance the momentum flux of the steady current (eastward branch). Although the analytical PN solution is useful and informative, it is cumbersome and difficult to apply to actual outflows. Here, a considerably simpler nonlinear analytical solution is presented. Using the idea that the eddies grow slowly relative to their rotation rate, it is shown that an intense (i.e., large Rossby number) and large relative vorticity outflow dumps most of its mass flux (Q) into the eddies (66%). (The remaining 33% goes into the eastward long-shore current.) By contrast, a weak outflow (i.e., an outflow with weak anticyclonic vorticity −αf, where α is analogous to the Rossby number and is much smaller than unity and f is the Coriolis parameter) dumps most of its water into the downstream current [(1–2α)Q]. Unexpectedly, this partition of mass turns out to be the same as the one taking place on an f plane. (Note that this is not at all the case for southward outflow nor is it the case for either eastward or westward outflow, where β alters the balance drastically.) Although the above partition of mass is independent of β, the size of the eddies generated by the above process is a function of β. It is given by [768g′Q/βπf 2α(2 − α)(1 + 2α)]1/5, where g′ is the reduced gravity. This gives a reasonable estimate for the Loop Current eddies’ size and generation frequency. Numerical simulations are in agreement with the above nonlinear solution, though the agreement is not necessarily any better than that of PN.

Effect of forward acceleration and negative pressure breathing on pulmonary diffusion

1962 ◽  
Vol 17 (6) ◽  
pp. 909-912
Author(s):  
Fred Zechman ◽  
Gustave Mueller
Keyword(s):  
Negative Pressure ◽  
Technical Assistance ◽  
Human Subjects ◽  
Pulmonary Ventilation ◽  
Pressure Curve ◽  
Experimental Conditions ◽  
Lung Volumes ◽  
Control Value ◽  
Negative Pressure Breathing ◽  
The Right

Forward acceleration decreases lung volumes, resembling negative pressure breathing (NPB). At 4 g the relaxation pressure curve is shifted downward and to the right 15 mm Hg. Pulmonary gas exchange and diffusion capacity were measured in nine human subjects during NPB (-15 mm Hg) and forward acceleration (4 g). Pulmonary ventilation increased approximately 40% in each condition. The O2 uptake increased with NPB (from 261 to 293 ml/min) and was slightly decreased or unchanged at 4 g. Carbon dioxide elimination increased in both experimental conditions. The apparent steady-state Dco was unchanged by NPB but decreased from an average control value of 21 to 12 ml/min mm Hg at 4 g. Since lung volumes are decreased by comparable amounts in both conditions, it is believed that the deleterious effects observed with forward acceleration are associated with the increased hydrostatic gradient from chest to back. Note: (With the Technical Assistance of Justin Taylor) Submitted on June 4, 1962

The Effects of Left Hand Fatigue on Right Hand Performance

1980 ◽  
Vol 24 (1) ◽  
pp. 643-646
Author(s):  
Marian E. Benton ◽  
Robert P. Bateman
Keyword(s):  
Bicycle Ergometer ◽  
Tracking Performance ◽  
Experimental Conditions ◽  
Left Hand ◽  
Tracking Tasks ◽  
Significant Decrement ◽  
Crossover Fatigue ◽  
Before And After ◽  
Hand Performance ◽  
The Right

Twenty-five subjects performed tracking tasks with the right arm before and after cranking a bicycle ergometer with the left arm. Three experimental conditions consisted of cranking the ergo-meter for 60, 90, and 120 seconds. The results indicate there was a significant decrement in tracking performance the first ten seconds after each of the cranking periods. By thirty seconds after cranking, tracking performance returned to pre-cranking level for each of the conditions. The decrement was not attributable to heart rate or breathing rate increases which remained for periods of up to five minutes. The crossover fatigue effect warrants further study.

scholarly journals Wind Modifications to Density-Driven Flows in Semienclosed, Rotating Basins

2010 ◽  
Vol 40 (7) ◽  
pp. 1473-1487 ◽  
Author(s):  
Cristóbal Reyes-Hernández ◽  
Arnoldo Valle-Levinson
Keyword(s):  
Pressure Gradient ◽  
Wind Stress ◽  
Flow Structures ◽  
Pressure Gradients ◽  
Coriolis Parameter ◽  
Maximum Water ◽  
The Right ◽  
Stress Variations ◽  
Wedderburn Number ◽  
Lateral Structure

Abstract An analytical two-dimensional model is used to describe wind-induced modifications to density-driven flows in a semienclosed rotating basin. Wind stress variations produce enhancement, inversion, or damping of density-driven flows by altering the barotropic and baroclinic pressure gradients and by momentum transfer from wind drag. The vertical structure of wind-induced flows depends on αH, the nondimensional surface trapping layer, where α is the inverse of the Ekman layer depth d and H is the maximum water depth. For αH > 5 wind-driven flow structures are similar to the Ekman spiral; for αH < 2 wind-driven flows are unidirectional with depth. The relative importance of density to wind forcing is evaluated with the Wedderburn number W = τ−1ρH2D, which depends on water density ρ, mean depth H, a proxy of the baroclinic pressure gradient D, and wind stress τ. Because D depends on α and therefore on the eddy viscosity of water Az, wind speed and Az both modify W. Moreover, wind direction alters W by modifying the pressure gradient through the sea surface slope. The effect of Az is also evaluated with the Ekman number E = Az/fH2, where f is the Coriolis parameter. The alterations of the density-driven flow by the wind-driven flow are explored in the E and W parameter space through examination of the lateral structure of the resulting exchange flows. Seaward winds and positive transverse winds (to the right facing up basin in the Northern Hemisphere) result in vertically sheared flow structures for most of the E versus W space. In contrast, landward winds and negative transverse winds (to the left facing up basin) result in unidirectional landward flows for most of the E versus W space. When compared to observed and numerically simulated flow structures, the results from the analytical model compare favorably in regard to the main features.

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