scholarly journals The emergence of a collective sensory response threshold in ant colonies

2021 ◽  
Author(s):  
Asaf Gal ◽  
Daniel Kronauer
Keyword(s):  
Social Dynamics ◽  
Internal State ◽  
Response Threshold ◽  
Sensory Response ◽  
Social Feedback ◽  
Ant Colonies ◽  
Biophysical Property ◽  
Size Dependent ◽  
Binary Network ◽  
Inhibitory Interactions

The sensory response threshold is a fundamental biophysical property of biological systems that underlies many physiological and computational functions, and its systematic study has played a pivotal role in uncovering the principles of neural computation. Here, we show that ant colonies, which perform computational tasks at the group level, have emergent collective sensory response thresholds. Colonies respond collectively to step changes in temperature and evacuate the nest during severe perturbations. This response is characterized by a group-size dependent threshold, and the underlying dynamics are dominated by social feedback between the ants. Using a binary network model, we demonstrate that a balance between short-range excitatory and long-range inhibitory interactions can explain the emergence of the collective response threshold and its size dependency. Our findings illustrate how simple social dynamics allow insect colonies to integrate information about the external environment and their internal state to produce adaptive collective responses.

scholarly journals Analysis of Bifurcation and Chaos of the Size-dependent Micro–plate Considering Damage

2019 ◽  
Vol 8 (1) ◽  
pp. 461-469 ◽  
Author(s):  
Xiumei Wang ◽  
Jihai Yuan ◽  
Haorui Zhai
Keyword(s):  
Internal State ◽  
Couple Stress Theory ◽  
Damage Model ◽  
Modified Couple Stress Theory ◽  
Damage Effect ◽  
Bifurcation And Chaos ◽  
Stress Theory ◽  
Size Dependent ◽  
Material Length Scale ◽  
Plate System

Abstract In this research, nonlinear dynamics and characteristics of a micro–plate system under electrostatic forces on both sides are studied. A novel model, which takes micro-scale effect and damage effect into account, is established on the basis of the Talreja’s tensor valued internal state damage model and modified couple stress theory. According to Hamilton principle, the dynamic governing equations of the size-dependent micro–plate are derived by variational method and solved via Galerkin method and the fourth order Runge-Kutta method. The effects of damage variable and material length scale parameter on bifurcation and chaos of the micro–plate system are presented with numerical simulations using the bifurcation diagram, Poincare map. Results provide a theoretical basis for the design of dynamic stability of electrically actuated micro- structures.

Dynamic analysis of sensory-inhibitory interactions in crayfish stretch receptor neurons

1990 ◽  
Vol 63 (6) ◽  
pp. 1508-1519 ◽  
Author(s):  
L. C. Barrio ◽  
W. Buno
Keyword(s):  
Sensory Response ◽  
Complex Dynamic ◽  
Fixed Integer ◽  
Periodically Driven ◽  
Sustained Oscillations ◽  
Paradoxical Effects ◽  
Crayfish Stretch Receptor ◽  
Receptor Neurons ◽  
Inhibitory Interactions ◽  
Simple Summation

1. The effects of regular and random inhibition at moderate rates on the sensory response evoked by sinusoidal stretches were investigated in slowly and rapidly adapting stretch receptors of crayfish (RM1 and RM2, respectively). 2. Although the RM1 has pacemaker properties and the RM2 is spontaneously silent, inhibitory postsynaptic potential (IPSP) effects were similar in both mechanosensory neurons. The most common consequence was the expected reduction of the sensory response and the increase of the elongation needed to reach firing threshold. With regular IPSPs there were regions where pre- and postsynaptic spikes alternated at fixed integer ratios, usually 1:1, more rarely 1:2 and 1:3. Increases or decreases of the sensory excitation caused sudden postsynaptic accelerations or decelerations when specific length bounds were crossed and where pre- and postsynaptic alternations changed to lower (e.g., from 1:1 to 1:2) or higher ratios (e.g., from 1:2 to 1:1), respectively. 3. Paradoxical effects were also observed because increasing or decreasing the inhibitory rate for a given alternation ratio (e.g., 1:1) accelerated or decelerated the output rate, respectively. Alternations and paradoxical behaviors disappeared with IPSP pattern irregularization. Random IPSPs strongly irregularized the receptor's output. Inhibition, especially if the pattern was irregular, could excite under special conditions. 4. With regular IPSPs, mechanical sensitivity became zero at the lengths at which receptors were silenced, low during alternations, and maximum at transitions between successive alternation ratios. Irregular IPSPs did not have this delinearizing consequence. 5. In conclusion, inhibition introduced important complex modifications in the coding of mechanosensory information. Effects were similar in both receptor types, indicating that self-sustained oscillations are not fundamental. The observed changes were critically dependent on pre- and postsynaptic rate and pattern. They cannot be explained by simple summation of converging sensory and inhibitory inputs and represent another observation of the complex dynamic behavior of periodically driven nonlinear systems.

Doctors and Patients: The Practice(s) of Nymphomania

1999 ◽  
Author(s):  
Ann Goldberg
Keyword(s):  
Strategic Behavior ◽  
Social Dynamics ◽  
Internal State ◽  
Social Contexts ◽  
Power Dynamics ◽  
Self Presentation ◽  
The Social ◽  
Poor Peasant ◽  
And Gender ◽  
The One

The peasant Margaretha D., noted the asylum log, “often suffers from hysterical attacks, with which she wants to be treated like a distinguished lady . . . She raises herself above her social position and demands great attention and care.” This patient, in other words, though considered mad by the Eberbach asylum, was not a true hysteric: she rather “played” the hysterical lady. Two important issues suggest themselves from this description of feigned illness. The first has to do with the connection between class, gender, and the representation of illness. Madness, it seems, had its class and gender codes. Certain symptoms of hysteria—which in the eighteenth century had become a fashionable illness of privileged women, signifying the pathologies accompanying luxury, leisure, and “civilization”—appeared suspicious in a poor, peasant woman. Secondly, the “playing” of illness suggests (inadvertently) a subtext, normally buried and only implicit in the asylum notes: of illness as strategic behavior on the part of the patient within the social dynamics of the asylum. Margaretha’s symptoms were at least in part the result of a self-presentation to her keepers, a communicative act, with its own aims—attention, better care, and so forth. Both of these issues—the link between class, gender, and illness, on the one hand, and the strategic nature of symptoms, on the other—are at the core of the following analysis of nymphomania. Nineteenth-century physicians interpreted the behavior of nymphomaniacal women as a function of an internal state of being—as pathologically excited genitals—and in this way, they contributed to the construction of a modern conception of sexuality as an innate essence of personality. While no longer a clinical entity in post-Freudian psychiatry, the image of the out-of-control, sex-obsessed nymphomaniac remains very much alive in popular culture and continues to be grounded in a conception of sexuality as inner essence and “drive.” This analysis, by contrast, looks at nymphomania as acts and attitudes, which took place within very specific social contexts: the power dynamics of the asylum and the doctor-patient relationship.

scholarly journals The Dynamics of Coalition Formation on Complex Networks

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
S. Auer ◽  
J. Heitzig ◽  
U. Kornek ◽  
E. Schöll ◽  
J. Kurths
Keyword(s):  
Decision Making ◽  
Phase Transitions ◽  
Complex Networks ◽  
Social Relations ◽  
Social Dynamics ◽  
Finite Size ◽  
Empirical Support ◽  
Coalition Structure ◽  
Economic Systems ◽  
Social Feedback

Abstract Complex networks describe the structure of many socio-economic systems. However, in studies of decision-making processes the evolution of the underlying social relations are disregarded. In this report, we aim to understand the formation of self-organizing domains of cooperation (“coalitions”) on an acquaintance network. We include both the network’s influence on the formation of coalitions and vice versa how the network adapts to the current coalition structure, thus forming a social feedback loop. We increase complexity from simple opinion adaptation processes studied in earlier research to more complex decision-making determined by costs and benefits and from bilateral to multilateral cooperation. We show how phase transitions emerge from such coevolutionary dynamics, which can be interpreted as processes of great transformations. If the network adaptation rate is high, the social dynamics prevent the formation of a grand coalition and therefore full cooperation. We find some empirical support for our main results: Our model develops a bimodal coalition size distribution over time similar to those found in social structures. Our detection and distinguishing of phase transitions may be exemplary for other models of socio-economic systems with low agent numbers and therefore strong finite-size effects.

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Transfer Technique for Electron Microscopy of Membrance Filter Samples

1974 ◽  
Vol 32 ◽  
pp. 554-555
Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Pore Size ◽  
Membrane Filters ◽  
Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

I Like Myself, I Really Do (at Least Right Now)

2020 ◽  
Vol 36 (1) ◽  
pp. 196-206 ◽  
Author(s):  
Almut Rudolph ◽  
Michela Schröder-Abé ◽  
Astrid Schütz
Keyword(s):  
Construct Validity ◽  
Performance Feedback ◽  
Repeated Measures ◽  
Temporal Stability ◽  
Social Feedback ◽  
Student Sample ◽  
Empirically Supported ◽  
Good Internal Consistency ◽  
And Performance ◽  
Induced Changes

Abstract. In five studies, we evaluated the psychometric properties of a revised German version of the State Self-Esteem Scale (SSES; Heatherton & Polivy, 1991 ). In Study 1, the results of a confirmatory factor analysis on the original scale revealed poor model fit and poor construct validity in a student sample that resembled those in the literature; thus, a revised 15-item version was developed (i.e., the SSES-R) and thoroughly validated. Study 2 showed a valid three-factor structure (Performance, Social, and Appearance) and good internal consistency of the SSES-R. Correlations between subscales of trait and state SE empirically supported the scale’s construct validity. Temporal stability and intrapersonal sensitivity of the scale to naturally occurring events were investigated in Study 3. Intrapersonal sensitivity of the scale to experimentally induced changes in state SE was uncovered in Study 4 via social feedback (acceptance vs. rejection) and performance feedback (positive vs. negative). In Study 5, the scale’s interpersonal sensitivity was confirmed by comparing depressed and healthy individuals. Finally, the usefulness of the SSES-R was demonstrated by assessing SE instability as calculated from repeated measures of state SE.

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