scholarly journals Phase Transitions and Macroscopic Limits in a BGK Model of Body-Attitude Coordination

2020 ◽  
Vol 30 (6) ◽  
pp. 2671-2736
Author(s):  
P. Degond ◽  
A. Diez ◽  
A. Frouvelle ◽  
S. Merino-Aceituno

Abstract In this article we investigate the phase transition phenomena that occur in a model of self-organisation through body-attitude coordination. Here, the body attitude of an agent is modelled by a rotation matrix in $${\mathbb {R}}^3$$ R 3 as in Degond et al. (Math Models Methods Appl Sci 27(6):1005–1049, 2017). The starting point of this study is a BGK equation modelling the evolution of the distribution function of the system at a kinetic level. The main novelty of this work is to show that in the spatially homogeneous case, self-organisation may appear or not depending on the local density of agents involved. We first exhibit a connection between body-orientation models and models of nematic alignment of polymers in higher-dimensional space from which we deduce the complete description of the possible equilibria. Then, thanks to a gradient-flow structure specific to this BGK model, we are able to prove the stability and the convergence towards the equilibria in the different regimes. We then derive the macroscopic models associated with the stable equilibria in the spirit of Degond et al. (Arch Ration Mech Anal 216(1):63–115, 2015, Math Models Methods Appl Sci 27(6):1005–1049, 2017).

2020 ◽  
Vol 25 (1) ◽  
pp. 46-71
Author(s):  
Marin Terpstra

Abstract In this article, using Spinoza’s treatment of the image of the political body, I aim to show what happens to the concept of a healthy commonwealth linked to a monarchist model of political order when transformed into a new context: the emergence of a democratic political order. The traditional representation of the body politic becomes problematic when people, understood as individual natural bodies, are taken as the starting point in political theory. Spinoza’s understanding of the composite body, and the assumption that each body is composed, raises the question of the stability or instability of this composition. This has implications for the way one looks at the political order’s conditions of possibility, I argue, and at the same time reveals the imaginary nature of the political body.


2011 ◽  
Vol 201-203 ◽  
pp. 2709-2716 ◽  
Author(s):  
Wei Wei ◽  
Xin Hui Liu ◽  
Yan Li Chen

In many fields’ rough-terrain vehicles, e.g., mineral exploration vehicles, military applications vehicles, vehicles that can move on rough terrains are desired. The ability of obstacle-climbing was affected by stability of vehicle. The stability of vehicle is closely related to the body attitude, which composes with a number of bodies. For this reason, in this paper, a wheeled mobile vehicle with 2 DOF articulated frame (2DWAV), for example, the new concept of correlative stability is presented. The stability of 2DWAV was analyzed based on static and dynamic in this paper, when it was driving on rough terrain. Finally, the simulation and experiment on rough terrain are carried out.


2019 ◽  
Vol 37 (2) ◽  
pp. 206-219
Author(s):  
Meindert E. Peters

Friedrich Nietzsche's influence on Isadora Duncan's work, in particular his idea of the Dionysian, has been widely discussed, especially in regard to her later work. What has been left underdeveloped in critical examinations of her work, however, is his influence on her earlier choreographic work, which she defended in a famous speech held in 1903 called The Dance of the Future. While commentators often describe this speech as ‘Nietzschean’, Duncan's autobiography suggests that she only studied Nietzsche's work after this speech. I take this incongruity as a starting point to explore the connections between her speech and Nietzsche's work, in particular his Thus Spoke Zarathustra. I argue that in subject and language Duncan's speech resembles Nietzsche's in important ways. This article will draw attention to the ways in which Duncan takes her cues from Nietzsche in bringing together seemingly conflicting ideas of religion and an overturning of morality; Nietzsche's notion of eternal recurrence and the teleology present in his idea of the Übermensch; and a renegotiation of the body's relation to the mind. In doing so, this article contributes not only to scholarship on Duncan's early work but also to discussions of Nietzsche's reception in the early twentieth century. Moreover, the importance Duncan ascribes to the body in dance and expression also asks for a new understanding of Nietzsche's own way of expressing his philosophy.


Author(s):  
Natalia Prodiana Setiawati ◽  
Joko Santoso ◽  
Sri Purwaningsih

The utilization of local food commodities such as corn and cassava with seaweed addition as a dietary fiber source for producing artificial rice through extrusion technology is an  alternative for food diversification. The research was carried out to find out the best composition (rice, corn, cassava, and seaweed) and temperature of extrusion process on making artificial rice and the influence of dietary fibre on sensory properties and physicochemical. The composition of rice, corn, and cassava in proportion  of 1:3:1 with 20% seaweed, Eucheuma cottonii, addition and temperature extruder of 90 °C were selected as the best product for artificial rice. The  sensory evaluation was 8.02±0.21 (people’s preference). In physicochemical properties, dietary fiber significantly affected on low bulk density and starch digestibility. This condition is very good for health especially in maintaining the stability of blood glucose in the body. Keywords: artificial rice, composition, extrusion, seaweed, dietary fibre, temperature


Author(s):  
Fesenko, H.

Purpose. Increasing the uniformity of distribution of mineral fertilizers and other bulk materials due to the stability of their feed from the body to the spreading working bodies using the top feeder. Methods. The following methods are used to achieve this aim: the method of comparing the differences between individual groups of fertilizers, the method of analyzing the properties of a new technical system, the method of functional inventiveness, and the methods of theoretical and analytical mechanics. Results. The traction body of the conveyor of the upper feed of the body fat body machine for mineral fertilizers and other bulk materials was substantiated and the relationship between the height of its scrapers and the distance between them was established, as well as the nature of the mineral fertilizer pressure on the curvilinear wall of the body. In addition, the design of the advanced body fertilizer spreader is justified, which ensures a stable flow of fertilizers from the body due to the improvement of the top feeder. Conclusions. Because of the conducted researches, the advantages of machines equipped with top feeder are found. They create the conditions for the forced feeding mineral fertilizers and other loose materials from the container to the distribution bodies, which is a prerequisite for their evenness on the surface. With this, the imperfection of known machines with the top feeder constrains their introduction into agricultural production. On this account, a more thoroughly constructed solution of the body feeder of the top feed is substantiated, in which the conveyor provides a stable supply of fertilizers from the body with reduced energy consumption during operation. Keywords: analysis, feed, upper device, conveyor, stability, fertilizers, flow ability, body.


2020 ◽  
Vol 14 (2) ◽  
pp. 108-125
Author(s):  
Apoorva Singh ◽  
Nimisha

: Skin cancer, among the various kinds of cancers, is a type that emerges from skin due to the growth of abnormal cells. These cells are capable of spreading and invading the other parts of the body. The occurrence of non-melanoma and melanoma, which are the major types of skin cancers, has increased over the past decades. Exposure to ultraviolet radiations (UV) is the main associative cause of skin cancer. UV exposure can inactivate tumor suppressor genes while activating various oncogenes. The conventional techniques like surgical removal, chemotherapy and radiation therapy lack the potential for targeting cancer cells and harm the normal cells. However, the novel therapeutics show promising improvements in the effectiveness of treatment, survival rates and better quality of life for patients. Different methodologies are involved in the skin cancer therapeutics for delivering the active ingredients to the target sites. Nano carriers are very efficient as they have the ability to improve the stability of drugs and further enhance their penetration into the tumor cells. The recent developments and research in nanotechnology have entitled several targeting and therapeutic agents to be incorporated into nanoparticles for an enhancive treatment of skin cancer. To protect the research works in the field of nanolipoidal systems various patents have been introduced. Some of the patents acknowledge responsive liposomes for specific targeting, nanocarriers for the delivery or co-delivery of chemotherapeutics, nucleic acids as well as photosensitizers. Further recent patents on the novel delivery systems have also been included here.


2021 ◽  
Vol 2 (1) ◽  
pp. 63-81
Author(s):  
Sajana Manandhar ◽  
Erica Sjöholm ◽  
Johan Bobacka ◽  
Jessica M. Rosenholm ◽  
Kuldeep K. Bansal

Since the last decade, the polymer-drug conjugate (PDC) approach has emerged as one of the most promising drug-delivery technologies owing to several benefits like circumventing premature drug release, offering controlled and targeted drug delivery, improving the stability, safety, and kinetics of conjugated drugs, and so forth. In recent years, PDC technology has advanced with the objective to further enhance the treatment outcomes by integrating nanotechnology and multifunctional characteristics into these systems. One such development is the ability of PDCs to act as theranostic agents, permitting simultaneous diagnosis and treatment options. Theranostic nanocarriers offer the opportunity to track the distribution of PDCs within the body and help to localize the diseased site. This characteristic is of particular interest, especially among those therapeutic approaches where external stimuli are supposed to be applied for abrupt drug release at the target site for localized delivery to avoid systemic side effects (e.g., Visudyne®). Thus, with the help of this review article, we are presenting the most recent updates in the domain of PDCs as nanotheranostic agents. Different methodologies utilized to design PDCs along with imaging characteristics and their applicability in a wide range of diseases, have been summarized in this article.


2006 ◽  
Vol 14 (2) ◽  
pp. 313-332 ◽  
Author(s):  
Daniel L. Schwartz ◽  
Taylor Martin

If distributed cognition is to become a general analytic frame, it needs to handle more aspects of cognition than just highly efficient problem solving. It should also handle learning. We identify four classes of distributed learning: induction, repurposing, symbiotic tuning, and mutual adaptation. The four classes of distributed learning fit into a two-dimensional space defined by the stability and adaptability of individuals and their environments. In all four classes of learning, people and their environments are highly interdependent during initial learning. At the same time, we present evidence indicating that certain types of interdependence in early learning, most notably mutual adaptation, can help prepare people to be less dependent on their immediate environment and more adaptive when they confront new environments. We also describe and test examples of learning technologies that implement mutual adaptation.


1995 ◽  
Vol 3 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Michel Probst ◽  
Walter Vandereycken ◽  
Herman Van Coppenolle ◽  
Johan Vanderlinden

2008 ◽  
Vol 17 (08) ◽  
pp. 1179-1196 ◽  
Author(s):  
MARTÍN G. RICHARTE ◽  
CLAUDIO SIMEONE

We study spherically symmetric thin shell wormholes in a string cloud background in (3 + 1)-dimensional space–time. The amount of exotic matter required for the construction, the traversability and the stability of such wormholes under radial perturbations are analyzed as functions of the parameters of the model. In addition, in the appendices a nonperturbative approach to the dynamics and a possible extension of the analysis to a related model are briefly discussed.


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