scholarly journals The effect of changing topography on the coordinated marching of locust nymphs

2016 ◽  
Author(s):  
Guy Amichay ◽  
Gil Ariel ◽  
Amir Ayali
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
System Level ◽  
Desert Locust ◽  
Limited Extent ◽  
Major Barrier ◽  
Marching Bands ◽  
The Impact ◽  
Theoretical Results

Collective motion has traditionally been studied in the lab in homogeneous, obstacle-free environments, with little work having been conducted with changing landscapes or topography. Here, the impact of spatial heterogeneity on the collective motion exhibited by marching desert locust nymphs was studied under controlled lab conditions. Our experimental circular arenas, incorporating a funnel-like narrowing followed by re-widening, did not constitute a major barrier to the locusts; but, rather, mimicked a changing topography in the natural environment. We examined its effects on macroscopic features of the locust collective behavior, as well as the any changes in their marching kinematics. A major finding was that of the limited extent to which the changing topography affected system-level features of the marching locust group, such as the order parameter and the fraction of walking individuals, despite increased crowding at the funnel. Overall, marching kinematics was also very little affected, suggesting that locust marching bands adjust to the environment, with little effect on the overall dynamics of the group. These findings are in contrast to recent theoretical results predicting that environmental heterogeneities qualitatively alter the dynamics of collectively moving particles; and highlight the crucial role of rapid individual plasticity and adaptability in the dynamics of flocks and swarms. Our study has revealed other important features of the marching behavior of the desert locust in addition to its robustness: the locusts demonstrated both, clear thigmotaxis and a tendency to spread-out and fill the available space.

scholarly journals The effect of changing topography on the coordinated marching of locust nymphs

2016 ◽  
Author(s):  
Guy Amichay ◽  
Gil Ariel ◽  
Amir Ayali
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
System Level ◽  
Desert Locust ◽  
Limited Extent ◽  
Major Barrier ◽  
Marching Bands ◽  
The Impact ◽  
Theoretical Results

Collective motion has traditionally been studied in the lab in homogeneous, obstacle-free environments, with little work having been conducted with changing landscapes or topography. Here, the impact of spatial heterogeneity on the collective motion exhibited by marching desert locust nymphs was studied under controlled lab conditions. Our experimental circular arenas, incorporating a funnel-like narrowing followed by re-widening, did not constitute a major barrier to the locusts; but, rather, mimicked a changing topography in the natural environment. We examined its effects on macroscopic features of the locust collective behavior, as well as the any changes in their marching kinematics. A major finding was that of the limited extent to which the changing topography affected system-level features of the marching locust group, such as the order parameter and the fraction of walking individuals, despite increased crowding at the funnel. Overall, marching kinematics was also very little affected, suggesting that locust marching bands adjust to the environment, with little effect on the overall dynamics of the group. These findings are in contrast to recent theoretical results predicting that environmental heterogeneities qualitatively alter the dynamics of collectively moving particles; and highlight the crucial role of rapid individual plasticity and adaptability in the dynamics of flocks and swarms. Our study has revealed other important features of the marching behavior of the desert locust in addition to its robustness: the locusts demonstrated both, clear thigmotaxis and a tendency to spread-out and fill the available space.

scholarly journals The effect of changing topography on the coordinated marching of locust nymphs

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2742 ◽  
Author(s):  
Guy Amichay ◽  
Gil Ariel ◽  
Amir Ayali
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
System Level ◽  
Desert Locust ◽  
Limited Extent ◽  
Major Barrier ◽  
Marching Bands ◽  
The Impact ◽  
Theoretical Results

Collective motion has traditionally been studied in the lab in homogeneous, obstacle-free environments, with little work having been conducted with changing landscapes or topography. Here, the impact of spatial heterogeneity on the collective motion exhibited by marching desert locust nymphs was studied under controlled lab conditions. Our experimental circular arenas, incorporating a funnel-like narrowing followed by re-widening, did not constitute a major barrier to the locusts; but, rather, mimicked a changing topography in the natural environment. We examined its effects on macroscopic features of the locust collective behavior, as well as the any changes in their marching kinematics. A major finding was that of the limited extent to which the changing topography affected system-level features of the marching locust group, such as the order parameter and the fraction of walking individuals, despite increased crowding at the funnel. Overall, marching kinematics was also very little affected, suggesting that locust marching bands adjust to the environment, with little effect on the overall dynamics of the group. These findings are in contrast to recent theoretical results predicting that environmental heterogeneities qualitatively alter the dynamics of collectively moving particles; and highlight the crucial role of rapid individual plasticity and adaptability in the dynamics of flocks and swarms. Our study has revealed other important features of the marching behavior of the desert locust in addition to its robustness: the locusts demonstrated both, clear thigmotaxis and a tendency to spread-out and fill the available space.

scholarly journals BOUNDARIES OF TRUST AND TRANSGRESSION: STUDYING THE CIRCULATION OF OBSCENE CONTENTS WITHIN ITALIAN PRIVATE GROUP CHATS

2019 ◽  
Vol 2019 ◽  
Author(s):  
Giovanni Boccia Artieri ◽  
Elisabetta Zurovac ◽  
Stefano Brilli
Keyword(s):  
Meaning Making ◽  
Instant Messaging ◽  
Participant Observation ◽  
System Level ◽  
Dark Side ◽  
Media System ◽  
Boundary Maintenance ◽  
Online Spaces ◽  
The Impact

Within the contemporary social media sphere we witnessed an exploitation of visible and permanent contents shared by users for platforms’ marketing purposes (i.e. selling data to advertisers) and to enable platforms to provide tailored experiences. This, along with data breaches scandals, triggered concerns about privacy and the dangers of mass surveillance, and lead developers to provide Instant Messaging applications with greater security. However, the existence of this kind of ‘safe spaces’ in which users privacy is not menaced, has also raised the attention on the sharing of transgressive, obscene or offensive contents that eludes public scrutiny. While the mainstreaming of such contents in non-public digital spaces is often cited as one of the hallmarks of the “dark side of the web”, the research on this topic is still lacking as this phenomenon is observable mostly at an interactional level, and not at the mass media system level. Our study provides an analysis of users’ meaning-making and boundary maintenance activities regarding violent/pornographic contents in group chats (WhatsApp and Telegram), that combines participant observation and in-depth interviews with active participants of such groups. We expect that the results of this research will improve the understanding of 1) the role of messaging apps affordances in shaping the circulation of extreme contents, 2) group trust dynamics, 3) the impact of a common semantics of the obscene on the cultivated semantics of public sphere, 4) methodological difficulties in researching online spaces unreachable by web scraping approaches.

scholarly journals Active phase field crystal systems with inertial delay and underdamped dynamics

2020 ◽  
Vol 43 (7) ◽  
Author(s):  
Dominic Arold ◽  
Michael Schmiedeberg
Keyword(s):  
Phase Field ◽  
Collective Behavior ◽  
Collective Motion ◽  
Active Phase ◽  
Inertial Motion ◽  
Density Peaks ◽  
Motion State ◽  
Crystal Model ◽  
Phase Field Crystal

Abstract. Active matter systems often are well approximated as overdamped, meaning that any inertial momentum is immediately dissipated by the environment. On the other hand, especially for macroscopic systems but also for many mesoscopic ones particle mass can become relevant for the dynamics. For such systems we recently proposed an underdamped continuum model which captures translationally inertial dynamics via two contributions. First, convection and second a damping time scale of inertial motion. In this paper, we ask how both of these features influence the collective behavior compared to overdamped dynamics by studying the example of the active phase field crystal model. We first focus on the case of suppressed convection to study the role of the damping time. We quantify that the relaxation process to the steady collective motion state is considerably prolonged with damping time due to the increasing occurrence of transient groups of circularly moving density peaks. Finally, we illustrate the fully underdamped case with convection. Instead of collective motion of density peaks we then find a coexistence of constant high and low density phases reminiscent of motility-induced phase separation. Graphical abstract

scholarly journals Obstacle avoidance in social groups: new insights from asynchronous models

2015 ◽  
Vol 12 (106) ◽  
pp. 20150178 ◽  
Author(s):  
Simon Croft ◽  
Richard Budgey ◽  
Jonathan W. Pitchford ◽  
A. Jamie Wood
Keyword(s):  
Obstacle Avoidance ◽  
Information Transfer ◽  
Social Preferences ◽  
Collective Motion ◽  
Social Structures ◽  
Collision Risk ◽  
Group Navigation ◽  
The Impact ◽  
The Relationship

For moving animals, the successful avoidance of hazardous obstacles is an important capability. Despite this, few models of collective motion have addressed the relationship between behavioural and social features and obstacle avoidance. We develop an asynchronous individual-based model for social movement which allows social structure within groups to be included. We assess the dynamics of group navigation and resulting collision risk in the context of information transfer through the system. In agreement with previous work, we find that group size has a nonlinear effect on collision risk. We implement examples of possible network structures to explore the impact social preferences have on collision risk. We show that any social heterogeneity induces greater obstacle avoidance with further improvements corresponding to groups containing fewer influential individuals. The model provides a platform for both further theoretical investigation and practical application. In particular, we argue that the role of social structures within bird flocks may have an important role to play in assessing the risk of collisions with wind turbines, but that new methods of data analysis are needed to identify these social structures.

scholarly journals Self-organization of collective escape in pigeon flocks

2021 ◽  
Author(s):  
Marina Papadopoulou ◽  
Hanno Hildenbrandt ◽  
Daniel W.E. Sankey ◽  
Steven J. Portugal ◽  
Charlotte K. Hemelrijk
Keyword(s):  
Collective Behavior ◽  
Computational Models ◽  
Collective Motion ◽  
Specific Model ◽  
Self Organization ◽  
Predator Prey ◽  
Behavioral Rules ◽  
Bearing Angle ◽  
Species Specific

Bird flocks under predation demonstrate complex patterns of collective escape. These patterns may emerge by self-organization from simple interactions among group-members. Computational models have been shown to be valuable for identifying the behavioral rules that may govern these interactions among individuals during collective motion. However, our knowledge of such rules for collective escape is limited by the lack of quantitative data on bird flocks under predation in the field. In the present study, we analyze the first dataset of GPS trajectories of pigeons in airborne flocks attacked by a robotic falcon in order to build a species-specific model of collective escape. We use our model to examine a recently identified distance-dependent pattern of collective behavior that shows an increase in the escape frequency of pigeons when the predator is closer. We first extract from the empirical data the characteristics of pigeon flocks regarding their shape and internal structure (bearing angle and distance to nearest neighbours). Combining these with information on their coordination from the literature, we build an agent-based model tuned to pigeons' collective escape. We show that the pattern of increased escape frequency closer to the predator arises without flock-members prioritizing escape when the predator is near. Instead, it emerges through self-organization from an individual rule of predator-avoidance that is independent of predator-prey distance. During this self-organization process, we uncover a role of hysteresis and show that flock members increase their consensus over the escape direction and turn collectively as the predator gets closer. Our results suggest that coordination among flock-members, combined with simple escape rules, reduces the cognitive costs of tracking the predator. Such rules that are independent of predator-prey distance can now be examined in other species. Finally, we emphasize on the important role of computational models in the interpretation of empirical findings of collective behavior.

scholarly journals Aberrant Patterns of Sensory-Evoked Activity in the Olfactory Bulb of LRRK2 Knockout Mice

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3212
Author(s):  
Andrea Maset ◽  
Marco Albanesi ◽  
Antonio di Soccio ◽  
Martina Canova ◽  
Marco dal Maschio ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Intracellular Signaling ◽  
System Level ◽  
Strong Impact ◽  
Lrrk2 Gene ◽  
Evoked Activity ◽  
Sensory Evoked ◽  
The Impact

The LRRK2 gene is the major genetic determinant of familiar Parkinson’s disease (PD). Leucine-rich repeat kinase 2 (LRRK2) is a multidomain protein involved in several intracellular signaling pathways. A wealth of evidence indicates that LRRK2 is enriched at the presynaptic compartment where it regulates vesicle trafficking and neurotransmitter release. However, whether the role of LRRK2 affects neuronal networks dynamic at systems level remains unknown. Addressing this question is critical to unravel the impact of LRRK2 on brain function. Here, combining behavioral tests, electrophysiological recordings, and functional imaging, we investigated neuronal network dynamics, in vivo, in the olfactory bulb of mice carrying a null mutation in LRRK2 gene (LRRK2 knockout, LRRK2 KO, mice). We found that LRRK2 KO mice exhibit olfactory behavioral deficits. At the circuit level, the lack of LRRK2 expression results in altered gamma rhythms and odorant-evoked activity with significant impairments, while the spontaneous activity exhibited limited alterations. Overall, our data in the olfactory bulb suggest that the multifaced role of LRRK2 has a strong impact at system level when the network is engaged in active sensory processing.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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